METHOD AND ARRANGEMENTS FOR THE DAMPING OF OSCILLATIONS

The invention refers to a method for the damping of the oscillations of an object and proposes a number of innovative arrangements through which the aforementioned method is embodied. More specifically, the present invention proposes a principle of operation for hydraulic dampers (and, preferably, for dampers which are utilized in vehicle suspensions) and said principle is totally different from the principle which is currently adopted by the present technical level.

According to the known technical level, the damping of the energy of the oscillation -via the conventional hydraulic dampers- leads to the increase of the temperature of the working fluid. On the contrary, in the hydraulic dampers which are proposed by the present invention, the damped energy of the oscillation does not lead to the increase of the temperature of the working medium (the damping fluid) but, instead, it promotes the change of its state, from liquid to gaseous, with a decrease (under certain circumstances) of its temperature. In figure 1 is shown a body (1) of definite mass which body is suspended elastically and is able to move vertically, varying its distance from a point (4) of a reference level. This elastic connection, of the present example, is performed via a spring (2), the oscillation of which is dampened via a damper (3) and said damper consists of a moving member (3A) -which is connected to the oscillating body (I)- and from a stationary member (3B) which is connected to the point (4) of the reference level.

The relevant technical level of the known dampers (figure 2) which utilize a fluid working medium (named, also, as telescopic hydraulic dampers) proposes the existence of at least one -controllably sealed- chamber of variable volume. Said chamber is called, hereinafter, as sealed working chamber (100) -and, briefly, as "working chamber" - and is formed between the moving piston (12) and the body (1010) of the damper where, said body (1010) consists of the cylinder (10) -inside which the piston is moving- and from two suitable caps which are located at each end of the cylinder, via which caps the inner of the cylinder is sealed against the outside environment.

Between the moving member (piston) and the stationary member (body) of the damper - of which the working chamber (100) consists- there is a quantity of damping fluid (mineral oil, usually) of suitable viscosity. During a certain (relative to each other) movement of the aforementioned two members of the damper, there is a reduction of the volume of the sealed working chamber. As it can be seen, the chamber is formed between the piston and the extreme wall (11) -which is called, also, as "wall"- and said wall belongs to the cap of the damper body. The gradual reduction of the volume of the sealed chamber, between the aforementioned two solid objects, leads to the enforced displacement of the oil (named, also, hereinafter, as "hydraulic medium" or "damping fluid") and, consecutively, leads to its enforced passing through passages (5) -restrictive to the flow- which are formed in the piston (12). The force, which originates from the

resistance of the passages against the flow of the oil, has the opposite direction to that of the variable (in magnitude and direction) force of the oscillation. And the end result of this procedure is the damping of the oscillation via the transformation of the kinetic energy of the oscillating body to a corresponding amount of thermal energy which is developed inside the mass of the hydraulic medium.

It is usual, in the everyday practice, to co-exist, inside the same hydraulic damper, two sealed chambers, where each chamber is located at each side of the moving piston. Th figure 2, the broken line indicates, the existence of a second cap and, consequently, the existence of a second, immobilized, extreme wall (11 ). Between this second extreme wall (11 ') and the piston (12) exists a second sealed chamber which, in the same depiction, is symbolized as "100"'. During the reverse movement of the piston, the oil of this second chamber (100') is displaced towards the first chamber (100), via the aforementioned passages — and is flowing, of course, always to an opposite direction, relatively to this of the piston.

Hereinafter, in the case where the motion of the moving member of the damper is executed to a direction which leads to the reduction of the total length of the telescopic damper (like this which is indicated by the arrow on the piston of figure 2) then, this certain action of the damper will be called as "compression of the damper". And more specifically, the motion of the piston, under said circumstances, will be called, hereinafter, as "compressive motion" or "compressive movement". On the other hand, the situation where the movement of the moving member is executed to the opposite -to the aforementioned- direction, it will be called as "rebound of the damper". And the motion of the piston -under those circumstances, where the damper is "rebounding"- will be called, hereinafter, as "rebound motion" or "rebound movement" of the piston.

The elementary operation principle of the conventional hydraulic dampers is the opposite to the operation principle of the hydraulic dampers which are proposed by the present invention. More specifically, the operation principle of the conventional dampers proposes that the pressure which exists inside the sealed chamber will remain, always, higher than the ambient pressure. (It is worth mentioning that, due to the high velocity of the oil flow, through the restrictive passages of the damper, it is possible to be developed, locally, an oil pressure which is lower than the ambient pressure - a fact which, generally speaking, is undesirable for the operation of the conventional dampers).

The enforced oil flow through the passages of a conventional damper has two main characteristics: the first is the increased velocity (and, hence, the pressure drop, inside the passage) and the second is the increase of the oil temperature. These two factors contribute to the developing of an undesirable phenomenon which is called, in the technical level, as cavitation. The result of the cavitation is the forming of bubbles inside the oil mass and, if the conditions are adverse, occurs the "foaming" of the oil which degrades the operation of the damper. To avoid the presence of the cavitation, the majority of the contemporary hydraulic dampers are "pressurized" — which means that the inside of the damper is kept constantly, in a pressure significantly higher than the ambient, via sealed "high pressure gas chambers", which are incorporated in the damper.

(To avoid any misunderstanding, it must be defined that the term "sealed working chamber" refers to a chamber which communicates with certain passages for the controlled inflow and outflow of a fluid and said chamber remains sealed against any other fluid flow except that which is performed via the aforementioned selected passages).

In many applications of the technical level (i.e. the suspensions for off-road motorcycles) there has been a technical choice according to which there is not an identical flow resistance during the compression and the rebound of the damper. On the contrary, it is decided that the behavior of the vehicle (and, also, the compliance, affecting the user) is enhanced whenever the resistance of the damper, during its compression, is almost nil and, on the other hand, the resistance during the rebound is augmented in order to perform a "critical" or, even "supercritical" damping of the oscillation.

OPERATING PRINCIPLE OF THE INVENTION

The object of the present invention is the developing of a totally different (to that of the technical level) operating principle for a new type of hydraulic dampers, either they are the sole oscillation absorbing elements of a suspension or they are auxiliary elements which are connected (in series or in parallel, according to the application) to conventional hydraulic dampers in order to provide an assistance to their operation and take over a part of their mechanical and thermal loads.

The proposed operating principle of the present invention is absolutely opposite to that of the conventional hydraulic dampers. More specifically, the piston of the present invention (called also, hereinafter, as the "main piston") does not apply pressure to the hydraulic medium, in order to enforce it to pass through the aforementioned "flow restrictive passages". On the contrary, the piston creates, inside the working chamber, a partial vacuum which is applied, temporarily, on the whole mass of damping fluid which exists inside the working chamber. And said vacuum enforces the damping fluid to change "matter state" and, doing so, a part of the damping fluid is transformed in the gaseous state while the rest residuals in its previous, liquid state. And, additionally, this liquid state is characterized by a comparatively lower temperature.

In figure 3 a is shown an indicative application of the suggested method according to the spirit of the present invention. The lower edge point (8K) of the damper (3) is connected to an external support and the inside of the damper contains a suitable liquid, which is called, hereinafter, as liquid damping medium (7) (or, briefly, as "hydraulic medium"). The aforementioned hydraulic medium occupies the space between the stationary (relatively to the body of the damper) wall (11) and the moving -relatively to the body (1010) of the damper- frontal wall (1000) of piston (12). In this case, the gradual increase of the distance between the piston (12) and the stationary extreme wall (11) of the cylinder (10) leads to the corresponding increase of

the (controllable sealed) volume of the space between the "moving wall" -namely, the frontal wall of the piston (1000)- and the stationary extreme wall (11). Consequently, there is a gradually increasing vacuum, inside the working chamber (100), which provokes (under certain circumstances) the change of the state of matter (vaporization) for a part of the hydraulic medium (7), accompanied by a corresponding absorption of energy.

The frontal wall of the piston (1000), in this case, is the main factor of the changes of the magnitude of the volume . Hence, generally, the "moving wall" of the working chamber of this invention will be called, also, as "variable volume wall" (1000).

The operating principle is based upon the existence of a valve (preferably, of the "oneway" type, which, in Ae technical level terminology, is also known and as "check- valve"). This valve is called, henceforth, as bleeding valve (17) and, in this indicative embodiment of figure 3 a, it is located onto the piston (12). Assuming that this certain damper is at a vertical position, then, the bleeding valve (17) is located on the highest point of the inner space of the working chamber (100).

The presence of the bleeding valve (17) at the highest point of the working chamber (100) ensures that, before the beginning of the next stroke of the operation of the damper, the produced vapours from the hydraulic medium will be removed away from the working chamber, via the bleeding duct (170). A bleeding valve (17) can be located at anyone of the two ends of the corresponding bleeding duct (170) and, preferably, to its end, in the working chamber.

The positive displacement of said vapors, away from the working chamber (100), can be accomplished either via the reversal of the motion of the piston — which piston, after the completion of its initial movement has, now, a new direction of motion, towards the stationary wall (11) or, alternatively, in a more compound embodiment of the invention, the enforced exit of the vapours can be accomplished via the enforced inflow of damping fluid, as it will be explained afterwards. Obviously, the desired result can be accomplished via a combination of the two aforementioned actions.

In figure 3b is shown a "reversed" version (of the arrangement which is shown in figure 3a) according to which the stationary extreme wall (11) is located on top of the cylinder and is equipped with at least one bleeding valve (17). Via this way, the outflow of the gaseous state of the damping medium (7) -from the working chamber (100)- follows a path outside the damper (3), until it arrives to a certain location where it undergoes a condensation processing in order to be re-introduced (under its liquid state) inside the damper, during a following operation cycle.

FIELDS OF USEFUL UTILISATION OF THE PRESENT INVENTION The liquid damping medium can consist of any suitable solution -eg water solution, organic solution, emulsion- or, even, it can consist of pure water. It is feasible, also, the

combustion fuel of the vehicle to be utilized as a liquid damping medium, provided that there are volatile constituents in its composition. It is worth to be mentioned that one of the feasible uses of the present invention is the separation, via the utilization of the proposed dampers, of the liquid state from the gaseous state of the fuel without the need to add heat. Obviously, in this certain case, there are more than one alternative embodiment versions (according to two diametrically different, feasible strategies) for the handling of the (combustible) damping medium, after its exit from the damper. The first of these strategies proposes the re-dissolving of the separated gaseous state inside the liquid state. The second strategy, proposes the utilization of the gaseous state separately from the liquid. In this case (and under certain operational conditions) it is advisable that the consumption -by the engine- of the gaseous state of the fuel must be performed via a different pathway, compared to that of the liquid state. This certain utilization possibility enables -under certain circumstances- the engine to consume the gaseous state while it is pre-mixed, homogenously, with the intake air of the engine. In this case, the mixing can be performed, indicatively, just before the introduction of this mixture inside the combustion chamber. Immediately afterwards, the addition -to the air/fuel mixture- of the liquid state of the fuel, via injection, is performed via a suitable injector. And preferably, the aforementioned injector is located inside a combustion chamber (in a "direct injection" configuration) of the engine.

In any case, and independently of the selected strategy (consumption, by the engine, of the gaseous state of the fuel via a separate way from that of the liquid state or consumption of the gaseous state after its re-dilution in the liquid state) it is profound that, via the proposed method by the present invention, there is a feasibility of utilization of the "spent" energy -which is produced from the wheel suspensions of a moving vehicle- in order to reduce the temperature of the fuel, before its introduction inside the engine. This possibility is mostly usable from the engines of off-road vehicles which are operating in very hot climates. It is also feasible to utilize the present invention as an assisting element of the air- conditioning system of the vehicle. This can be performed via the circulation of one of the two fuel states (gaseous or liquid - after its exit from the damper), via a heat exchanger, prior its introduction to the engine. The vehicles which are operating in hot environment can benefit from the present invention in the case, where, the hydraulic medium of the proposed damper consists of a water solution of a volatile substance - ammonia, par example. Obviously, this situation can be very supporting for the air conditioning system of the vehicle in case where the damping medium of the vehicle is circulated through any appropriate device -heat exchanger, par example- of the known technical level (the description of which is beyond the scope of the present invention).

In most cases it is understandable that the cooling abilities of an ordinary fluid -which is vaporized inside a "state change" damper of this invention-, are not sufficient for the air conditioning needs of the passenger compartment of a vehicle. This happens due to the fact that the flow of the -subject to vaporization- is very low, whenever the suspension

travel is below a level. On Hie other hand, this cooling capacity can be adequate for the cooling of the body of a rider on an "off-road" motorcycle due to the large travel of the wheel suspensions of such a kind of vehicle (and the fact that these suspensions present a great degree of mobility whenever the use of the certain vehicle takes place over a rough surface). In this case, it is suggested, by the present invention, that the cool hydraulic fluid (after its partial vaporization) is circulated inside a "crash protective" preferably) article of clothing of the rider where said article of clothing incorporates the appropriate passages for the circulation of said cooling fluid. Most preferably, it is suggested that the cool fluid which is coming from the "state change damper" is not transferred directly to the rider's article of clothing but, instead, it is transferred into a heat exchanger wherein it cools another (neutral) fluid which, finally, circulates inside the said cooling article of clothing. IQ this case, any accidental leakage of the fluid which circulates inside said article of clothing will not have any undesired effect on the rider or the environment - especially in the case where the liquid, which circulates inside the damper, is flammable or corrosive.

SPECIFIC EMBODIMENTS OF THE INVENTION The magnitude of the resistance which is applied on the moving part of the damper, during the enforced enlargement of the volume of the working chamber, depends on the kind of the hydraulic medium, its temperature and, also, the magnitude of the developed vacuum, inside the working chamber. The magnitude of the vacuum depends on the existing concentration of vapours -inside the working chamber- where said vapours are "non-swept" residuals from the previous operating cycle -or, even, a sequence of cycles.

In order to perform -during the rebound motion of the piston- an approximate control of the magnitude of the vacuum which is created inside the working chamber, it is advisable to exist at least one device -called, henceforth, as "feeding passage"- through which it is performed a controlled inflow of hydraulic medium into the working chamber. Said feeding passages are attached, according to each certain case, at an appropriate location on a moving or stationary wall of the working chamber (100).

In figures 4a and 4b are shown the aforementioned feeding passages (169), the flow of which is controlled by corresponding (and adjustable, preferably) control valves (9) which are located on a reeding duct (909). The term "valve", in this case, incorporates any suitable arrangement through which is performed a controlled resistance to the flow of a fluid which moves to a desired direction. The advisable existence of "one-way" outflow valves (16) enables the possibility to avoid the inflow of the gaseous state of the damping fluid inside the feeding duct (909), during the compression of the damper.

The operation of the control valves (9) can be performed, accordingly, via any suitable proposition which originates from the technical level. This operation can be, par example, "intermitted" (of the "on-off ' type) or can be continuous, providing a constant or variable

chocking of the flow. The activation arrangement of these valves can follow any other appropriate method which is provided by the technical level. Par example, these valves can be controlled by pre-loaded springs via which the valves permit the opening (or control the magnitude of the opening) from the moment at which, inside the working chamber, the magnitude of the vacuum ( from which the related damping force which is produced), exceeds a predefined value. Obviously, it is more advisable (although more complicated) the control of the valves to be performed in real time, via a suitable electronic arrangement and in accordance either to the signal of a pressure sensor which is located inside the working chamber or the signal of a force sensor which is located between the damper and the oscillating body (which is elastically suspended) or, finally, located between the oscillating body and its reference base. Via this way, it is feasible to achieve a satisfactory harmonization of the momentary damping resistance with the various damping needs, during the operation of the device. The fluid hydraulic medium which flows through the aforementioned control valves (and said medium is being sucked by the arising vacuum, inside the working chamber, during the rebound of the damper) is possible to enter, inside the working chamber, under the "shape" of an extremely thin fluid flow (or a flow of very thin droplets) which flow passes through the existing gaseous state of the damping fluid. In this case, the "overexposed" surface of the flowing -in such a way- liquid will provoke its quicker vaporization, in comparison to the vaporization of the exposed surface of the liquid damping fluid which already exists, in a practically still condition, inside the working chamber. Via this way, the desired action will be performed more intensively (according to the kind of the damping fluid, the said "desired action" either is the vaporization of the damping fluid, itself, or the vaporization of a volatile constituent which is diluted inside the damping liquid).

The arrangement shown in figure 4a is constituted by the minimum number of parts which are necessary for the operation of the present invention, in a first, elementary embodiment. The piston (12) is equipped with at least one "one-way" bleeding valve (17) through which the damping fluid can pass through (in gaseous or liquid state or, even, as a mixture of gaseous and liquid states). This -passing through- damping fluid, is originated from the working chamber (100) whenever the piston moves towards the extreme wall (11). In this certain case, is shown (indicatively) the accumulation of a quantity of hydraulic medium, in liquid state, inside the closed space which is behind the piston - and this space is called, hereinafter, as auxiliary working chamber or, briefly, as auxiliary chamber (100A). According to the spirit of the present invention, whenever the piston of the damper executes a "compressive" movement, the gaseous state of the hydraulic medium flows through the piston and crosses -as array of bubbles- the aforementioned accumulation of liquid state which is "sitting" on top of the piston. (It is defined that, as "compressive" -opposite to the aforementioned "rebound"- is called this certain motion of the piston during which the volume of the working chamber is being reduced). The "one-way" inflow valve (16) permits, during the rebound motion of the piston, the inflow of a new quantity of liquid damping medium, into the working chamber (100) -

and this inflow is accomplished, via small quantities which are controlled by the control valve (9). The incoming fluid is provided, in this case, by an external storage tank (90).

In figure 4b is shown an alternative variant of the previous arrangement whereas the control valves (9) and the bleeding valve (17) are located onto the piston. In this certain case, the controlled inflow -inside the working chamber (100)- of the fluid, comes from the auxiliary chamber (100A). Additionally, the outflow of the gaseous state from the sealed working chamber is performed through the rod (13) of the piston (12) - and said rod (13) is hollow and operates, also, as a bleeding duct (170). The gaseous state of the hydraulic medium outflows from the rod (13) via outflow holes (14). Said holes can be located either inside the auxiliary chamber (100A) or, even, outside the damper. In this case, the fluid -which outflows from the working chamber- can be transferred to a suitable device wherein it undergoes a certain process (par example: dilution of the gaseous state to the liquid state) prior its reintroduction inside the damper.

In figure 5 a is shown a piston (12) which is equipped with a control valve (9) of a special type which enables a kind of "regulation" of the flow. More specifically, a part (at least) of the piston is of a "spongy" or porous material which consists of a plurality of minute passages (121) through which flows tile hydraulic fluid which comes from the auxiliary chamber (100 A). Said fluid is sucked from the working chamber (100) due to the pressure difference which arises during the rebound motion of the piston. According to the spirit of the present invention, the damping fluid must undergo a cavitation, inside its mass, during its outflow inside the working chamber (100), in order to achieve a -more or less, violent- separation of its gaseous state from the liquid state. In figure 5b is shown a control valve (9), of a special shape, which consists of a movable, spongy or porous, outflow device (122). The magnitude of the exposed (inside the working chamber) surface of said movable device is defined by the momentary "intensiveness" of the vacuum (which is developed inside the working chamber) in relation to the resistance which applies to this outflow device a spring (125) with which it is connected. In figure 5c is shown an arrangement which have a similar principle of operation with that of figure 5b. In this case, the control of the flow of the hydraulic medium is performed via an injector (123) of a special shape and function. Said injector consists of multiple outflow holes (124) which are uncovered sequentially and the number of the uncovered holes, at any moment, depends on the pressure difference between the auxiliary chamber (100 A) and the working chamber (100) and, additionally, the resistance from the compressive spring (126). In the three cases, which are shown in figure 5, the different locations of the bleeding valve (17) are just indicative and not binding.

In figures 6a and 6b is shown, indicatively, the operation principle of a rather complex variation of the present invention. This arrangement consists of a closed cylinder (10) inside which a piston (12) is moving and said piston (12) functions as a common wall for a working chamber (100) and an auxiliary chamber (100A). These two chambers communicate via at least one bleeding valve (17) which, in this certain depiction, is located onto the piston (12) and, also, said bleeding valve permits the flow of hydraulic medium (being in liquid and gaseous state) from the working chamber (100) to the auxiliary chamber (100A) but not vice-vers&The working chamber (100) is supplied with

hydraulic medium (7) which is coming from a storage tank (90) -via a flow pump (99)- and the flow of the hydraulic medium, towards the working chamber (100), is controlled via an adjusting control valve (9). In this example, the control valve is of the "on-off ' type but this is not binding for the certain application. Accordingly, the auxiliary chamber (100 A) is connected to the storage tank (90) via an overflow duct (901).

In figure 6a is shown a proposed embodiment of damper, during the rebound motion of the piston (12). Ih this case, during the period where the control valve (9) is closed, the continuous increase of the volume of the working chamber (100) leads to the reduction of the pressure (P2) in its inside. The result of this action is the partial vaporization of the hydraulic medium and the development of a resistance force - and, generally speaking, the absorption of energy. Meanwhile, the upward (according to the depiction) motion of the piston (12) leads to the displacement of a corresponding volume of the hydraulic medium, from the auxiliary chamber (100A) to the storage tank (90). During the upward motion of the piston, it is possible to be controlled (if it is desired) the maximum value of the applied, on the piston, resisting force - which resisting force is related to the vacuum which is being developed inside the working chamber (100). This kind of control can be achieved via a controlled leakage of hydraulic medium towards the working chamber (100); for example, this can be achieved after one or more instantaneous "opening- closing" of the adjusting control valve (9). The system via which the control valve (9) is activated (according to the instant pressure which exists inside the working chamber) can be of any suitable type which is provided by the known technical level for similar appliances (for example, it can be a mechanical or hydraulic system, which is activated by the pressure inside the working chamber or, in case of a more precise control, the system can be of the electric or electronic type, consisting of pressure sensors and control unit etc.). For simplicity reasons, the depiction of any other alternative embodiment of said system (and which executes the activation of the control valve) is omitted, due to the fact that all the alternative embodiments arise with an obvious way from the known technical level. Profoundly, is not excluded the possibility of the utilization of any one of the solutions which were presented in figure 5 — in this case, the control valve (9) remains constantly shut, during the upward motion of the piston and, consecutively, via this way, is succeeded a significant simplification of the whole arrangement.

In figure 6b is shown the operation of the arrangement, which is already shown in figure 6a, after the completion of the upward motion of the piston (12) and the beginning of its downward motion. In this case, the control valve (9) opens and the hydraulic medium (in liquid state) -displaced by the flow pump (99)- inflows inside the working chamber (100). Due to the fact that, inside the working chamber (100), the pressure (P2) is higher than the pressure (Pl) which exists inside the auxiliary chamber (100A), this pressure difference promotes the flow of hydraulic medium from the working chamber to the auxiliary chamber, via the bleeding valves (17). At its starring moment, the flow of the hydraulic medium begins from its gaseous state which is accumulated (due to its "buoyancy") at the highest points of the working chamber. Profoundly, the highest points of the working chamber are the underside of the piston (12), provided that the damper is in the vertical position. Under these circumstances, the gaseous state is enforced to be displaced and, via the bleeding valves (17), it passes into the auxiliary chamber (100 A).

Via this way, is ensured the elimination of the gaseous state inside the working chamber - and, consecutively, its absence at the start of the next upward movement of the piston. The absolute elimination of the gaseous state, during the upward movement of the piston, is of significant importance due to the fact that, via this way, it is ensured that the desirable beginning of the "creation of vacuum" coincides with the very first moment of the downward movement of the piston. The existence of at least one (of the "one -way" type, preferably) overflow valve (216), between the auxiliary chamber (100A) and the storage tank (90), is definitely desirable due to the fact that, when it shuts -during the downward movement of the piston- then, a sufficient vacuum is beginning to develop, inside the auxiliary chamber (100 A). And said vacuum, inside the auxiliary chamber, enables a more efficient flow of hydraulic medium from the storage tank (90) to the working chamber (100). It is obvious, also, that in cases where the piston (12) covers a long distance, during its movement, it is possible, for the proposed damper, to have a satisfactory operation without the existence of any flow pump (99).

In figure 7a is shown an operational detail which is fundamental for an alternative embodiment of the present invention. It is called, hereinafter, as "bound valve" (15), which is connected to the (so called, hereinafter) lower edge point (8K) of the damper. The bound valve (15) opens (permitting the flow of hydraulic medium to the working chamber) only when the damper is in compression, with the piston moving towards the extreme wall (11). In this specific figure is shown, as bound valve (15), a valve of the "seating type" (or "poppet valve") in order to simplify the explanation of its operating principle. Obviously, any other suitable type of valve can be utilized (i. e. rotating valve) provided that it is connected to the damper via a similar way like the one of figure 7a and, of course, it follows the operating principle which will be presented immediately.

The opening of the bound valve (15) permits the inflow of damping liquid (7) from the storage tank (90) and, subsequently, enables the displacement (of the incoming liquid) of the gaseous state from the working chamber (100) via at least one bleeding valve (17), which is located onto the piston (12). The existence of a (relatively soft) bound valve spring (30) -which is located between the lower edge point (8K) and the "body" (1010) of the damper- is suggested, in order that the bound valve (15) will remain closed whenever the damper is, temporarily, not in action. As it can be understood, from the depiction, during the compressive (downward) motion of the piston, the whole body (1010) -hence, also the cylinder (10)- of the damper moves towards the lower edge point (which is considered, here, as a stationary point of reference), compressing the spring (30) of the bound valve (15). The result of this movement (towards the lower edge point) of the cylinder (10) is, profoundly, an equal movement of the extreme wall (11) towards the same direction. Under these circumstances, the seat of the bound valve (15) moves downwards -against the spring (30) which is being compressed- while the bound valve (15) remains still, due to its rigid connection with the still lower edge point (8). The end result is the uncovering of the passage, which is controlled by the bound valve (15), permitting, so, the inflow of (liquid) damping fluid.

At the beginning of the upward motion of the piston, the whole body (1010) of the damper -including the cylinder (10), profoundly- moves upwards, relatively to the lower edge point which is considered, always, as point of reference. The result is the equal movement, to the same direction, of the extreme wall (11) up to the point where the seat of the bound valve comes in contact with the bound valve (15) itself. The result of this contact is the sealing of the aperture of the passage which is controlled by the bound valve (15). At this point, it is worth noting that the damping force, which is "produced" during the upward motion of the piston (12), is transferred to the rod of the bound valve (15) via the contact between the bound valve (15) and the extreme wall (11) - and, also, the damping force is applied, via the bound valve (15), to the lower edge point (8K) of the damper. Considering that, during the operation of the bound valve, there is a lateral movement of the whole body of the damper, it is not desirable, in some cases, to have a movement of the storage tank (90) of the hydraulic medium. Ih the case where the storage tank (90) is immobilized at a still point, its connection with the damper can be performed via a flexible element (401) — like, par example, this which is shown as a part of the feeding duct (909)- or via a sliding connection (402) which is not preferable due to sealing problems which arise, sometimes, at this type of connection.

In figure 7b is shown, indicatively, an arrangement of four bleeding valves ( 17), located on the face of a piston (12) which is similar to that of figure7a

The transfer of hydraulic medium to the bound valve can be performed via the gravity or, preferably, via an enforced circulation which can be aided by the pressure differences which exist between the storage tank, the working chamber and the auxiliary chamber, during the upward motion of the piston. In this case it is suggested to incorporate a pressure chamber to the feeding (with hydraulic medium) circuit of the damper. Said pressure chamber must be kept at an internal pressure (Po) which is higher than the ambient. In figure 7a is shown, indicatively, a pressure chamber (9091) which is incorporated into the storage tank (90). This specific chamber consists of a separating membrane (9093) and its pressure is adjusted via a pressure valve (9092). It is obvious that the existence of a pressure chamber in the storage tank (90) is not binding. On the contrary, it can be located at any other external point of the hydraulic circuit and, preferably, it can be a branch of the feeding duct (909) as it is indicated by the dotted line. It is possible, also, to avoid the existence of a separate pressure chamber (9091) and to substitute this certain function via the accumulation of the gaseous state of the hydraulic medium inside the sealed storage tank, exploiting the inflow of the gaseous state - which inflow originates from the damper, during the rebound motion of the piston. In this case -and assuming that the storage tank (90) has an adequate capacity for the liquid state of the hydraulic medium- it is possible to achieve an approximate control of the momentary pressures, during the operation of the damper, via the continuous re- dilution of the gaseous state (or part of it) into the liquid state. This strategy is aided by the increased pressure which exists inside the storage tank. This procedure can be enhanced, also, by a provision according which the inflow of the gaseous state into the storage tank -after its exit from the damper- is not performed over the surface of the liquid state. On the contrary, it is suggested that this inflow is performed under the surface wherein said gaseous state is moving as a flow of bubbles. Obviously, the desired

reliability of the system can be achieved when the enforced circulation of the hydraulic medium is assisted by a flow pump which (preferably and not binding) coexists with a pressure chamber. In figure 8a is shown, indicatively, an embodiment of the present invention according which the inflow of the hydraulic medium inside the working chamber -during the compressive movement of the piston- is performed via enforced circulation. And, more specifically, it is performed via a reciprocating pump consisting from a piston which is coaxially connected to the piston (12) of the damper. According to the arrangement which is shown in the figure, at the end of the cylinder which surrounds the working chamber (100) there is another cylinder which is called, hereinafter, as reciprocating flow pump (19). Inside said flow pump is reciprocating a flow pump piston (21) the diameter of which is (preferably and not binding) greater that that of the piston (12) of the working chamber. The aforementioned flow pump piston (21) divides the inner volume of the flow pump in a flow pump primary chamber (22) and a secondary flow pump chamber (23). The piston (12) of the damper and the piston (21) of the fiowpump are connected via a connecting rod (20) which, in this example, is a part of the axial extension of the rod (13) of the piston (12). Profoundly, in this specific -and just indicative- application, the two pistons (of the damper and of the flow pump) are moving simultaneously.

During every rebound movement of the piston (12) of the damper, the piston of the flow pump (21) is pulled to the same direction and is being fed, via the flow pump primary chamber (22), with hydraulic medium which comes from the storage tank (90). Meanwhile, due to the fact mat at the edge points (8A, 8K) of the damper are applied pulling forces, the bound valve (15) remains closed, according to those which have been said at the description of figure7a.

Alternatively, during the compressive motion of the piston (12), the compressive forces, which are applied to the ends of the damper, enforce the body (1010) of the damper to move towards the stationary lower edge point (8K) of the damper - and the result is the opening of the bound valve (15). At the same time, the flowpump piston (21) moves downwards and "sweeps" the fluid to the outside of the primary flow pump chamber (22). This fluid is transferred, via the open bound valve (15), to the flowpump outflow duct (25). From there, via the "one-way" inflow valve (16), the hydraulic medium arrives inside the working chamber (100). The "one-way" flow pump valve (116) -which controls the flow, from the storage tank (90) to the flow pump (19)-, does not permit to the fluid of the flow pump primary chamber (22) to return into the storage tank (90).

In figure 7b is shown an alternative -but not most preferable- location for the "one-way" inflow valve (16).

If there is an adequate amount of liquid hydraulic medium which is displaced by the flow pump piston (21) of figure 7a, then it is ensured that, whenever this quantity is introduced into the working chamber (100), its amount is sufficient to perform a full displacement of the remaining gaseous state. The gaseous state is enforced to pass through the bleeding valves (17) -which, in this depiction, are located onto the piston (12)- and is transferred

(with apart of the incoming liquid state) inside the auxiliary chamber (100A). Then, via the overflow valve (216), the displaced fluids arrive either directly into the storage tank (90) or, just before that, they are passing through a condensation unit (27) wherein it is performed the partial or total dilution of the gaseous state into the liquid. The conditions under which the said dilution will be performed are defined according to the quantity of the gaseous state which is desired to be diluted into the liquid. These conditions are the temperature of the gaseous state (which can be higher or lower than that of the hydraulic medium) and the temperature of the cooling liquid which is circulated inside the heat exchanger (270) of the condenser. As it will be explained later, it is preferable, sometimes, to utilize the exiting (from the damper) liquid as cooling medium for the cooling of a device (of the vehicle) or a compartment, etc. This can be performed either by the direct utilization of the hydraulic medium which exits from the damper or via the utilization of an intermediate fluid - like this, par example, which is circulating inside the heat exchanger (270).

In figure 9a is shown an alternative arrangement, similar (in operation) to that of figure 8a. The difference, here, is that the bound valve is replaced by an adjustable "one-way" valve (31), the operation of which is defined by the static pre-loading of its spring. This kind of (adjustable) "one-way" valve (31) does not permit the flow except in the case where the pressure difference, at its ends, is greater than a specified value. Via this way, it is ensured that the valve will remain closed whenever there is a vacuum, inside the working chamber (100), during the rebound motion of the piston (12). On the opposite, during the compressive motion of the two pistons -the one which belongs to the working chamber and the other which belongs to the flow pump (12 and 21, respectively)-, the overpressure which arises inside the flow pump primary chamber (22) will enforce the adjustable "one-way" valve (31) to permit the flow from the flow pump primary chamber (22) to the working chamber (100), via the flow pump outflow duct (25)

In figure 9b is shown, indicatively, a kind of condensation unit (27) which performs the same operation (condensation of the gaseous state into the liquid state) with the device which is shown in figure 8a. The difference between the two is that the condensation is performed via the consumption of mechanical work which is derived from the motion of the vehicle suspensions. The condensation unit of this kind operates according known elements of the technical level and consists of a reciprocating piston -called, hereinafter, as condenser piston (28)- which piston, in this specific depiction (which is indicative, but not binding), is coaxial with the piston (12) of the working chamber and, additionally, is attached onto the same rod (13). The condensation unit (27) is fed, by the auxiliary chamber (100A), via (at least) one "one-way" overflow valve (216). In this simplified embodiment, the exit of the compressed mixture (consisting from gaseous and liquid state) from the condensation unit (27) is performed via (at least) one "one-way" valve which, henceforth, is called as "condenser outflow valve" (131). The condenser outflow valve (131) opens to only one direction of the flow and only whenever the pressure inside the condenser surpasses a certain value (which value is defined via the preloading of the spring of the valve). Profoundly, any one skilled in the art is able to apply, at this specific case, any suitable arrangement, with similar operating characteristics, following the spirit of the present invention.

In figure 9c is shown, indicatively, another embodiment of the present invention, according to which the working chamber (100) is located to the opposite side of the piston (compared to that which is already described in figure 8 a). Correspondingly, the flow pump primary chamber (22) is located to the opposite side of the flow pump piston (21). In this specific case, the communication between the flow pump primary chamber (22) and the working chamber (100) is performed via a hollow connecting rod (20) and an adjusting "one-way" valve (31) which operates in a similar way to the one which is presented in figure 9a. This simplified arrangement does not have an auxiliary chamber - like the (100A), in figure 8 a- and, consequently, the exit of the "one-way" bleeding valve (17) can be utilized, simultaneously, as direct exit to the storage tank (is not shown).

Finally, in figure 9d, is shown an arrangement -which is similar to that of figures 8 and 9 (a to c)- ₃ according to which the connection between the piston (12) of the working chamber (100) and the piston of the flow pump (21) is indirect, via a primary

(compressive) spring (32) which lies between the connecting rod (20) and the piston (21) of the flow pump (32). Additionally, a secondary (compressive) spring (33) lies between the piston (21) of the flow pump and the extreme wall (34) of the flow pump (32) and is "commissioned" to apply a "return" force to the flow pump piston (21) whenever it completes its downwards motion which executes when being pushed by the connecting rod (20). Via this way, the piston of the flow pump continues to execute simultaneous movements with the piston of the working chamber and always towards the same direction with it. The difference -which arises from the presence of the springs- is that the distances which are covered by the piston (21) of the flow pump are not, now, equal to the distances which are covered by the piston (12) of the working chamber. In fact, they are smaller (depending on the resistance of the springs) resulting in the reduction of the total length of the damper.

What was described, according to figure 7, was a "simple action" damper with a closed hydraulic circuit, with an inflow of hydraulic medium which is controlled via a bound valve, with a provision for the gaseous state to pass through the piston and, finally, with a provision for the exit (from the damper) of the gaseous state via valves of the "one-way" type. As it was mentioned before, the damping force is "produced' only during the rebound motion of the piston - hence, the characterization of this damper as "simple action". As it will be explained, the choice of a "simple action" damper is not binding for the embodiments of the present invention.

In figure 10 is shown, indicatively, a "double action" damper with a closed hydraulic circuit. This damper is equipped with two working chambers (100) -each one located at a corresponding side of the piston (12)- and provides damping force at both directions of the piston movement. From these two working chambers, the one which is under the piston (provided that the damper is positioned vertically) is called, hereinafter, as "lower working chamber" (100KA) and the other as "upper working chamber" (100 AN). The exit of the gaseous state from these two chambers is performed via "one-way" bleeding valves (17). The bleeding valve (17), via which the gaseous state escapes from the lower working chamber (100KA) is located at the end of the hollow rod (13) of the piston (12)

and the gaseous state is transferred outside the damper, via a transfer duct (1301) which is formed inside the hollow rod (13). The final exit of the gaseous state from the lower working chamber (100K) is performed via a moving exit hole (1302) and said hole is located on the rod (13) and is surrounded by a collector (1303). The gaseous state passes, via the exit hole, to the collector - and from the collector, via a connecting duct (1304), it is transferred to the storage tank (90). In the present embodiment, the collector (1303) is considered as stationary and the rod (13) is considered as sliding inside the immobilized collector (1303). This is a practical proposition provided that there is an adequate provision to avoid any leakages of hydraulic medium between collector (1303) and rod (13). In figure 10a, the piston (12) is shown at three different locations (during the operation of the damper) and, also, are shown the three corresponding locations of the exit hole (1302) while the rod (13) is sliding inside the collector (1303). Profoundly, a sufficient avoidance of leakage can be performed by a (not shown) arrangement whereas the collector (1303) is fixed onto the rod (13) and its connection with the storage tank (90) is performed via a duct which is constructed from a flexible material. The inflow of the hydraulic medium, inside the two working chambers, is performed via corresponding (and of the "adjusting" type, preferably) control valves (9) for which valves there is provision (mechanical or electromagnetic) to remain closed for the time period during which there is a vacuum inside the corresponding working chamber.

In picture 10b is shown, indicatively, the flow of hydraulic medium, inside the damper (3) whenever the motion of the piston is compressive. In this case -and according to the elements which were described before- the control valve (is not shown) of the upper working chamber (100AN) is closed. Consequently, the motion of the piston provokes a vaporization (of the hydraulic medium) inside this sealed chamber and, hence, the development of a resisting force against this motion. Simultaneously, the control valve (not shown) of the lower working chamber (100KA) is open, permitting so the inflow of liquid hydraulic medium and the displacement, via the hollow rod, of the gaseous state towards the collector (1303) -and, from there, to the storage tank (90). As it was mentioned before, the inflow of liquid hydraulic medium, into the lower working chamber (100KA), can be performed either temporarily -due to the pressure difference between the lower working chamber (100KA) and the storage tank (90), at the opening moment of the control valve - or permanently (which is the most preferable), via the enforced circulation of hydraulic medium, via a (not shown) flow pump of any suitable type (even one which is located remotely and powered independently).

In figure 10c is shown, indicatively, the flow of the hydraulic medium, into the damper (3), whenever the piston (12) executes a rebound motion. In this case, according to the aforementioned operational details, the control valve (not shown) of the lower working chamber (lOOKA) is closed. Consequently, the motion of the piston (12) provokes the beginning of a vaporization inside this sealed chamber and the development of a resisting force against this motion. At the same time, the open control valve (not shown) of the upper working chamber (100 AN) permits the inflow of liquid hydraulic medium and the displacement, via the corresponding bleeding valve (17), of the gaseous state towards the storage tank (90). As it was mentioned before, the inflow of liquid hydraulic medium, inside the lower working chamber, can be performed either temporarily -due to the

momentary pressure difference between the lower working chamber (100KA) and the storage tank (90), at the opening moment of the control valve- or (and preferably) via the enforced circulation of liquid hydraulic medium which is provided by a (not shown) flow pump of any suitable type.

At this point it is clarified that in the cases where there is not provision for a flow pump, the initial inflow of hydraulic medium, inside a working chamber, is provided by the pressure difference between the working chamber and the storage tank, at the end of the piston stroke. This situation leads to a temporary flow of liquid hydraulic medium which flow continues up to a certain moment where the aforementioned pressures are equalized. After this, the "sweeping" of the gaseous state from the working chamber, is performed via the movement of the piston towards the extreme wall of the chamber - in this case, the efficient "sweeping" of the gaseous state from the working chamber depends on the distance (preferably, as long as possible) which will be covered by the piston before the reversing of its movement.

In arrangements like that of figure 10, it is advisable that the activation of the adjustable control valves is being performed via electric or electronic control, according to the signal of a position sensor which monitors the motion of the piston. On the other hand, under these circumstances, it is feasible, also, the utilization of two (mechanically activated) bound valves like those which were, previously, described. In this case, each one of the two working chambers must have its own bound valve and, from these two valves, the first will open whenever the damper is subject to pulling forces and the other valve will open whenever the damper is subject to compressing forces.

Corresponding arrangements to the previous paragraph are shown, indicatively, in figures 11a and 1 Ib where it is depicted an alternative embodiment to that of figure 10. The valve, in this case, is called henceforth as "triodic bound valve" (115) and, for reasons of simplicity, is of the reciprocating type (notbindingly, of course) and is shown, indicatively, attached to the bottom of the lower working chamber (100KA). Profoundly, via a suitable connecting mechanism, any other similar type of valve (and, preferably, a rotating "triodic" bound valve) which is suitable for the specific application can be utilized. It is notified, also, that the presence of a flow pump (for the enforced circulation of fluid hydraulic medium) is strongly recommended, although it is omitted (for simplicity reasons) from the certain depiction.

The operating principle of this suggested arrangement is simple, due to the fact that it is similar to that which was already described concerning the arrangement of figure 10. More specifically, whenever the damper is in a "rebound" state, the triodic bound valve (115) moves backwards -relatively to the piston (figure 1 Ia)- and arrives at a suitable position in order to permit (via its internal structure) the flow of hydraulic medium, from the feeding duct (909) into the upper working chamber (100 AN). The liquid which inflows inside the upper working chamber (100 AN) displaces the remaining gaseous state from the previous operating cycle and enforces it to escape from the working chamber (via a bleeding valve (17) which is located onto the extreme wall. After this "sweeping", the gaseous state moves towards the storage tank. (Or the condensing unit, if exists).

Meanwhile, the lower working chamber (100KA) remains sealed and the motion of the piston (12) creates a drop of pressure, inside it Accordingly, the aforementioned pressure drop provokes the partial vaporization of the hydraulic medium and the development of a resisting force against the motion of the piston. On the contrary, whenever the damper is under compression (i.e. : downwards motion of the piston 12) the triodic bound valve (115) is moved towards the inside of the lower working chamber (lOOKA) (figure 1 Ib) and comes in a position where its internal structure permits the flow of hydraulic medium -from the feeding duct (909)- into, exclusively, the lower working chamber (100AN). The liquid which inflows inside the lower working chamber displaces τηv gaseous state of the previous cycle and said gaseous state escapes from the chamber via the bleeding valve (17) which is located at the end of the rod (13), in exactly the same manner as that in the case of figure 10. Meanwhile, due to the fact mat the upper working chamber (100KA) remains sealed, the motion of the piston creates, inside the upper working chamber, a pressure drop. Said pressure drop causes the appearance of a resisting force, which is applied between the ends of the damper, while the hydraulic medium undergoes a partial vaporization.

Until now, the terms "upper edge point" and "lower edge point" of a damper were used to describe a damper where the upper edge point is movable and connected to the piston of the working chamber and the lower edge point is considered as stationary and is connected either to the body of the damper or to a bound valve. At this point it is worth noting mat this viewing is "conventional" in order to simplify the description of the spirit of this invention and not binding for its embodiments. It is obvious, also, that the suitable modifications of the alternative structures which are already presented, provide the possibility to operate the present damper in a positioning which is the reversal of the considered, up to now, as "upright" . More specifically, it is feasible to operate a damper, according to the principle of the present invention, whereas the body of the damper is at the "upside" position and the rod of the piston in the "downside". Also, it is possible, according to the spirit of the present invention, to create a damper (of the "simple action" type, par example) which executes the enforced vaporization procedure during the compression of the damper instead of its rebound. The description of all these alternative cases is omitted due to the fact that they are profoundly understandable from any person skilled in the art. Until now, also, the piston was considered as rigidly connected to its rod. It is obvious that this acknowledgement is not binding for the operation of the present invention — on the contrary, the existence of a piston which has one degree of freedom relatively to its rod (axial movement) permits the successful embodiment of arrangements which are characterized by some operational advantages, in comparison to the arrangements which are described up to this point.

In figure 12, is shown a piston (12) which is not rigidly connected onto its rod (13) but, on the contrary, it is able to slip axially, between two limit points (132A and 132B) and its momentary location, across the rod, is controlled by a corresponding spring which is located in each side. Via this connection, the operation of the system takes place under an amount of hysteresis, whenever it is desirable. In practice, the benefit of this arrangement

is that it provides a momentum to the piston which continues its motion, for a while, after the momentary stopping of the rod (13), at each end of its travel. Additionally, in the case where there is a leakage (of hydraulic medium) between the rod and the piston (figure 12b), this leakage stops when the piston (12) is coming in contact with that limit point (132B) of which the location and the shape are provided suitably for the operational needs of a certain application. In figure 13b is shown a variation of this in figure 12 with the difference that during the axial movement of the piston on its rod, a passage is uncovered. According to any certain application, the aforementioned passage can be utilized as a passage for the inflow of liquid state or as a passage for the outflow of a gaseous state (and, additionally, this passage can, also, be utilized as a "one-way" valve).

In figure 13b, par example, is shown an application, according to which, during the downwards motion of the piston, it moves backwards (relatively to its rod) in order to uncover a bleeding duct (170) which connects the working chamber (100) with the auxiliary chamber (100 A). Generally speaking, it is possible, via this arrangement, to control the covering and uncovering of an extended passage (or two, successive) via which the liquid inflows into the working chamber or the auxiliary chamber. (The inflow into each one of the two chambers is defined by the motion —in compression or rebound- of the piston). In this case, the movement of the piston on its rod cancels the communication of the passage with the chamber inside which there is a temporary vacuum. This certain application, combined with a provision for the existence of suitable passages for the outflow of the gaseous state, can be utilized even in applications where the damper is of the "double action" type and consists of two working chambers, formed on each side of the piston. In figure 13 c, par example, the moving -backwards- of the piston (12), on its rod (13), uncovers a communication passage between the working chamber and a flow pump primary chamber (22).

In figure 14 is shown a simplified arrangement via which the fluid flow, through the piston (12), is permitted whenever it is moving to one direction but not to the other. It consists of two (ring shaped in the indicative -but not binding- example) control surfaces (12E, 12Z, respectively) from which at least one is movable and the other can be immobilized (or not) onto its seat and said control surfaces are equipped with passages (12D). These aforementioned passages do not coincide (figure 14b) whenever they are in contact, during the motion of the piston (12) - and, profoundly, they do not permit the fluid flow through mem. On the contrary, when the piston moves to the opposite direction, the resistance of the control surfaces to Ihe fluid flow enforces the movable control surface (12E) to move axially - relatively to the piston (12) - up to a distance from the other control surface (12Z). From the moment when the aforementioned control surfaces have a distance between them (figure 14a) the fluid (liquid or gaseous) is able to pass (sequentially) through their passage (12D) — provided that, in the meantime, the fluid has moved between these two control surfaces a (12E, 12Z).

In figure 15 is shown the shape of a piston (12) which is suitably shaped in order to enforce the flow, from the control valve (9), to run through the gaseous state of the hydraulic medium.

In figure 16 is shown a piston (12) inside of which, between the working chamber (100) and the auxiliary chamber (100 A), is formed a lubrication chamber (12X) inside of which there is a lubricating fluid which is different from the hydraulic medium of the damper. In figure 17 is shown a damper of which the piston (12) is not moving axially (like those already presented) but, on the contrary, it moves in an angular means, around an axis of rotation. This kind of structural arrangement is known from the technical level but, up to this point, it refers exclusively to conventionally operating dampers (operating via the enforced flow of compressed oil through restricting passages) — these dampers are called as "rotary dampers" or "angular displacement dampers". Profoundly, this kind of damper can be utilized as an alternative embodiment of the present invention, provided that it will be accordingly transformed under the spirit of the present invention. In figure 17a, par example, is shown an arrangement -relative to that of figure 10- via which a "double action" damper is embodied. In this case it is suggested, preferably, the choice of electrically activated control valves (9). In figure 17b is shown, indicatively, a composition of two angular displacement units from which the first is utilized as a damper (3) and the other is utilized as the flow pump (99) of the damper (3). For simplicity reasons, the fluid ducts which connect the two aforementioned units, are omitted. Finally, in figure 17c, is shown an arrangement whereas an angularly moving piston (12) -of at least one working chamber- and apiston of a flowpump (21) coexist inside the same body (1010) of a rotary damper (3) wherein both of the aforementioned pistons execute equal angular movements.

To ensure that the operation of anyone of the suggested (linear or rotary) dampers conforms with the prescribed efficiency provisions, it is necessary to perform a control of the quantity of vapours or gases which remain inside the working chamber whenever the piston begins a movement towards a direction according to which the volume of the working chamber increases. As it is already mentioned, the volume -at this certain moment- of vapors or gases must be, preferably, zeroed.

As it already mentioned, a suggested method to ensure the elimination of the "remaining" gases and vapors, at the beginning of the movement of the piston is via the continuous replenishment of the liquid state of the hydraulic medium -which action takes place inside the working chamber, whenever the piston is moving towards the stationary wall of the cylinder- and, consequently, performing the enforced (by the inflowing liquid) displacement of the gaseous state towards the outside of the working chamber.

In figures 18 and 19 is shown a suggested arrangement via which it is ensured a satisfactory "sweep" of the remaining gases or vapors, from the inside of the working chamber, at the beginning of the movement of the piston. It consists of an auxiliary piston (112) which is attached either onto the (main) piston (12) -as it is shown on the indicative embodiment of figure 18- or, alternatively, it is attached onto the still wall, as it is shown in the indicative arrangement of figure 19. In any case, the auxiliary piston is pushed, by an auxiliary piston spring (35), towards the inner space of the working chamber whenever an anchoring mechanism (36) is released.

The operation of the auxiliary piston can be summarized, in brief, according to the embodiment shown in figure 18.

Whenever the piston (12) of the working chamber is moving towards the -so called- "top dead point" of its travel, the auxiliary piston (112) is released from its anchoring (36) and moves -being pushed by its spring (35)- towards the inside of the working chamber (100). During this movement, the piston (12) displaces the gaseous state outside the chamber (fig. 18-IV). Also, during this action, the piston (12) continues its movement towards the stationary wall (11) (fig. 18- I), up to the moment where it reverses its movement, from downwards to upwards. At this certain moment (fig. 18- II), the anchoring mechanism (36) is activated and connects, securely, the auxiliary piston (112) to the (main) piston (12) — obviously, after this connection, the two pistons move together, as a unity, during the rebound movement of the (main) piston (12). At the moment of the reversal of the motion of the piston (12) -which coincides with the beginning of a new compression movement- the auxiliary piston is released from the anchoring mechanism and the described procedure is repeated for another operating cycle.

Under a similar concept, as that which is already described, the mechanism of the auxiliary piston operates in the alternative case where the auxiliary piston is anchored, temporary, on the stationary wall of the damper, as it is shown in the figure series 19. More specifically, starting from fig. 19- 1, the piston (12) executes a rebound motion while the auxiliary piston (112) remains immobilized via the anchoring mechanism (36). Profoundly, the temporary volume of the working chamber is, actually, the space between these aforementioned pistons. In the next operating stroke of the piston (fig. 19- IT) and, approximately, at the moment where the piston (12) begins its movement downwards, the auxiliary piston (112) is released from the anchoring mechanism. Accordingly, it is pushed by the spring (35) and is enforced to "run" through the working chamber, "sweeping" the gaseous state, up to the point where it meets the (moving downwards) piston (12). The gaseous state outflows form inside the working chamber via at least one bleeding valve (17) which, in this certain figure, is attached onto the piston (12). After this collision of the two pistons (figure 19-IH), the continuation of the downwards movement of the piston (12) enforces the auxiliary piston to move backwards up to the moment when the piston (12) reverses its motion in order to perform a new movement to the "upwards" direction. At this certain moment (fig. 19-IV), the anchoring mechanism is activated and immobilizes the auxiliary piston (112) up to the moment of the completion of the rebound cycle, accompanied by the vaporization of the hydraulic medium.

In the images shown in figures 18 and 19, the location and the operation of inflow and outflow valves, for the hydraulic medium, are omitted for reasons of simplicity. The accompanying description was limited up to the point of uncovering the operation principle of these certain embodiments. Following, there will be presented some indicative arrangements, according to this operating principle. In the images shown in figure 20, there is the presentation of two indicative embodiments of the suggested anchoring mechanism (36) and the method of releasing the auxiliary

piston (112) according to the motion and the momentary location of the piston (12) inside the working chamber (100). It is obvious that the arrangements of this kind present an unlimited variety which can be multiplied via the synthesis of mechanisms which are known from the technical level. And all the mechanisms, which are presented into this description (either they are simple mechanical arrangements or compound electromechanical devices) are proposed, exclusively, for exemplary reasons.

According to known operational elements originating from the technical level (and after an appropriate modification which enables their utilization in this certain application) it is feasible to use an unlimited variety of the known, available solutions which provide a restriction to the movement of the auxiliary piston (relatively to the motion of the main piston) via a dynamic utilization of fluids — i.e. a passage providing sufficient resistance to the flow of a fluid. In figure 20a is shown an arrangement for the control of the position of an auxiliary piston via an electromagnetic anchoring mechanism (36) which executes the commands of a digital controlling unit (42), according to the signal of a position sensor (41) which monitors the movements of the piston (12). The immobilizing and the releasing of the auxiliary piston (112), is performed via the entrance and exit of a locking catch (44) into a groove (43) which is formed onto the auxiliary piston.

In figures 20b and 20c the grooves (43) are formed onto the internal side of the auxiliary piston (112) and the locking catches (44) perform an angular motion around their fulcrum (45), according to the direction of the force which is applied to the outer extreme (8) of the damper. Whenever there is a pulling force, the locking catches open (broken line), enter inside the grooves (43) of the auxiliary piston and immobilize it. When the pulling force is ceased, the spring (30) pushes the edge point towards the inside of the damper, the locking catches move to the position which is indicated by the continuous line and the auxiliary piston is released - and, accordingly, it moves, pushed by the spring (35) up to the point where it meets the main piston. In the case where the two pistons have flat

"facial" surfaces, it is suggested that they must have spacing protrusions (46) in order to avoid coming in absolute contact of their "faces". Obviously, the aim is to leave a restricted volume, between the two said faces, wherein mere is a quantity of the hydraulic medium in a liquid state which will be vaporized when the two pistons are taken apart.

It is obvious that, after suitable modifications, the described inventive elements -referring to the concept of an auxiliary piston- can be applied, also, in embodiment cases where the auxiliary piston (112) is seated onto or into the main piston (12). In figure 21 is shown an arrangement according to which the auxiliary piston (112) is utilized as flow pump in order to pump a fluid which comes from the storage tank (90). Said fluid will be transferred inside the space between the main piston (12) and the auxiliary piston (112) and it will "sweep" the gaseous state, displacing it outside the working chamber, via bleeding valves (17). During the simultaneous -in the downwards direction (according to the specific figure)- movement of the two pistons (12,112) the fluid which is to the underside of the auxiliary piston is enforced to pass through the

auxiliary piston and to be transferred, to the outside, via an exit valve which is called, henceforth, as "controlled overflow valve" (47). The operation of said overflow valve (47) depends on an "activation protrusion" (48) which is located onto the main piston (12). Similarly to the previous example, at the moment when the piston (12) will start its upward motion, the anchoring mechanism (36) will immobilize the auxiliary piston (112) up to a next moment when the motion of the main piston (12) will be reversed. At this moment, the anchoring mechanism will release the auxiliary piston (112) which, being pushed by the spring (35), will move upwards. During this movement, the auxiliary piston will suck hydraulic medium (in liquid state) from the storage tank (90).

The practical application of all those described elements of the present invention is not restricted, exclusively, to dampers with main pistons which are moving axially. On the contrary, it is obviously feasible to apply also and in arrangements embodying "angular" or "rotary" dampers like those which were shown in figure 17. In this case, however, a suitable modification (concerning, par example, the shape of the working elements of the present invention) is necessary, in order to adapt the operation of the inventive elements in an environment of angular movements, instead of the axial movements which are presented up to this point. Profoundly, any person skilled in the relative art is able to execute the aforementioned suitable adaptation of the working parts of this invention.

In figure 22 is shown -in its "axial" version-, an application for "double action" operation. This arrangement is based upon all prescribed inventive elements and, profoundly, it could be applied -after suitable adaptation- in dampers of angular operation. These rotary dampers are characterized in that a great number of points of the surface of the piston (near the axis of rotation) are executing movements of a very limited magnitude. Ih said figure is shown a main piston (12) among two auxiliary pistons (112A, 112B) which operate in a similar manner to that which is already explained, according the figures 18 and 19. The primary characteristic of this configuration is that one of the two aforementioned auxiliary pistons is released by an anchoring mechanism and begins to move towards the surface of the main piston (12) at exactly the moment when the other surface of the main piston terminates its contact with the other auxiliary piston. (Which auxiliary piston, up to that moment, was moving backwards, compressing its spring, during its enforced displacement by the main piston). The procedure of this selective releasing of each one of the two auxiliary pistons can be materialized with a great variety of alternative electromechanical (or, even, simply mechanical) arrangements. In this specific application, is proposed a procedure according to which the releasing (via its anchoring mechanism) of a first auxiliary piston (i. e. the indicated as 112A) happens whenever the main piston (12) ceases the pressure which applies onto a trigger (113B) which is located on the second auxiliary piston (112B). A similar application (and equally effective) can be provided in the case where the trigger (113B) is located on the corresponding side of the main piston (12) and is compressed by the corresponding auxiliary piston (112B). In this figure is not shown -for reasons concerning the simplification of the description- any electric/electronic unit via which the operation of the present arrangement is controlled. More specifically, this hypothetical controlling unit (of any type, originating from the known technical level and suitably adapted to the present application) is responsible for the activation of the anchoring devices. Also, for

simplicity reasons, the relative locations through which the hydraulic medium enters and exits from the device, are omitted. (These details can be materialized -according to the already presented spirit of the invention- by any person skilled in the art, in an almost unlimited plurality of alternative embodiments).

In figure 23 is shown the main piston (12) of a "double action" damper. This piston is carrying two auxiliary pistons (one at each side of its) which are elastically connected, via springs, with said main piston (12). This certain arrangement can be utilized from all the -already described- applications of the present invention.

In the case where the arrangement of figure 23 is applied (after suitable modifications) to a "rotary damper", the auxiliary pistons are connected to the main piston and either they follow an angular motion or they move in the space, remaining parallel to a reference plane which belongs to the main piston. Also, this certain arrangement offers, to a relatively skilled in the art person, plenty of profoundly arising alternative solutions, according to the spirit of the present invention.

In figure 24 is shown, indicatively, a rotating bound valve (15R) which permits the flow of hydraulic medium whenever the damper is in compression (figure 24a) and restricts the flow whenever the damper is in a rebound motion (figure 24b). This action is performed via the connective arrangement between the valve and a reference point. In the figure is depicted (just indicatively) an example of connection -or activation procedure- of the bound valve. (The fact is that this connection can be performed via many alternative ways). In the specific example, the operation of the specific arrangement is performed via the connection of the rotating bound valve (15R) with an arm (2000) which rotates around a reference point or axis (2001) and said reference point, in the specific example, is the point via which the damper (3) is connected to the reference point. The permissible movement -relatively to said reference point- of the damper, during its compression, is restricted, in this indicative example, by a "stopper" (2002), which does not permits any more movement of the damper towards the reference point.

In figure 25 is shown an arrangement which operates correspondingly with that of the figure 24a. In this specific example, there is a "triodic" rotating bound valve (15R) which permits the flow of hydraulic medium, towards a first direction, whenever the damper is under compression and towards a second direction, whenever the damper is executing a rebound movement.

In figure 26 is shown an arrangement which utilizes the oscillations of a mass for the transformation of a part of a liquid, in gas. The certain arrangement is able to operate either as an autonomous device or as an auxiliary device of a conventional damping system with which the said arrangement is connected either in series or in parallel. In this last case, it is preferable that the "change state" operation of the certain damper is providing an assisting force to the conventional damping system with which, par example, the suspension of a vehicle is equipped. In some of these applications it is preferable to avoid the direct connection between the piston (12) and the oscillating mass. On the contrary, this connection -between the damper and the mass- can be performed via

the auxiliary rod (1220). The piston (12) is of a suitable shape, in order to be equipped (preferably, via the centre of its face) with a passage which is controlled by a control valve (9). This control valve (9) is able to adjust the flow and, preferably, it can be of the "one-way" type in order to permit the flow whenever the pressure difference between its ends exceeds a predefined (constant or variable) value. In this case, the valve opens and permits the fluid flow from the auxiliary chamber (100A) to the working chamber (100) which is formed between the piston (12) and the extreme wall (11) of the device.

The surface of the top of the piston (12) is shaped suitably in order to form -on its side which is not exposed inside the working chamber (100)-, a collecting bowl for the hydraulic medium (7) and the bottom of said bowl ends at the control valve (9). The "roof of the (exposed inside the working chamber) surface of the piston, is suitably shaped - like a dome or cone, par example. At the highest point of said "roof, a control valve (9) is attached, in order to provide a direct communication between the control valve (9) and the region where the gaseous state is concentrating, inside the working chamber (100). The (so called, henceforth) control spring (930) of the control valve (9) ends against the extreme wall (11) of the body (1010) or, more conveniently, it ends on a stable extension of wall (11), according to the desired length of said spring and, also, the desired variation of the resisting force of the spring, during its compression. In this specific figure, is shown an innovative version according to which the control spring (930) is the exclusive resisting element during the "backwards" movement of the piston (12). (This choice is not binding for the certain embodiment since it is feasible to exist, also, a separate -additional- spring which lies between the piston and the stationary extreme wall. Via this additional spring, is produced a force which pushes the piston upwards and said force is added to the force which is already exerted to the piston via the spring of the control valve). Summarizing, it is understood that, under the spirit of the present invention, it is not necessary to exist, inside the working chamber, only the control spring (930) of the control valve (9). On the contrary, the piston (12) can be pushed upwards via any other -supplementary- spring or any corresponding, suitable arrangement (of the technical level) the description of which is omitted due to their profound operation in this certain appliance.

At any time moment, during the movement of the piston (12), it is understood that the distance of the piston (12) from the extreme wall (11) -and, consequently, the momentary length of the control spring (930)- is the factor which defines the pressure with which the control valve (9) seals its passage. Any increase of said distance means a corresponding decrease of the pressure with which the control valve is pressed against its seat.

The operating principle of the arrangement which is shown in figure 26a is as follows. In a first time period, the auxiliary rod (1220), which is (preferably) under ambient pressure, pushes the piston (12) downwards and, during a second time period, it returns to its initial position. During this return movement, it is followed by the main piston (12) which is moving upwards, with a slower velocity, being pushed by a return spring. In this indicative arrangement, the spring which pushes the main piston is the control spring (930). The momentary pressure, which the "one-way" control valve (9) applies against its seat, is in direct relationship to the momentary length of said control spring (930). During

the upward movement of the main piston, a vacuum is created inside the working chamber (100) and, as already said, the vaporization of the contained liquid state occurs. Meanwhile, the main piston (12) continues its movement, upwards, and the gaseous state which is produced leads to a gradual drop of the magnitude of the vacuum which is exerted inside the working chamber (100). Additionally, the increasing distance of the main piston from the extreme wall (11), leads to the elongation (and the corresponding "unloading") of the control spring (930). From the moment when the force which the spring applies to the control valve (9) is sufficiently low, the pressure difference between the two faces of the control valve (9) overcomes the resistance of the spring and the valve opens, permitting the entrance (inside the working chamber) of the liquid which is accumulated over the control valve (9). In this case (and according to the situation) it is possible, after the opening of the control valve, to begin an upward flow of gaseous state, towards the auxiliary chamber (100A) — from where the gaseous state will be transferred to the outside. The "one-way" exit valve (191) is there to protect the device of flooding, whenever the accumulation of the liquid state exceeds a limit.

There is, also, an alternative case where the stationary end of the control spring is not in contact with the extreme wall -on the contrary, it is in contact with the piston itself. In this case, the resistance of the valve (against the action of opening it) would be constant, independently of the momentary distance between the piston and the edge wall. This is a feasible but not preferable -in certain cases- embodiment of this specific application.

In practice, is more desirable a configuration where the contact between the auxiliary rod (1220) and the piston (12) is not direct, in order to avoid the crashing between them at the point where they meet each other. Preferably, this contact is performed via an intermediate resilient element. In figure 26b, par example, the connection is performed via a connective spring (1222). At the other end of the rod (1220) is shown, indicatively, an oscillating mass (M), with which the rod is directly connected. Profoundly (and according to the specific demands of any different application) it is feasible to avoid the direct connection between the mass (M) and the rod (1220). Instead, this connection is performed, preferably, via an intermediate element of elastic or visco-elastic material.

In figure 26c is shown an arrangement via which it is performed a better adjustability for the opening "timing" of the control valve (9). More specifically, the auxiliary rod is equipped with an "activating" protrusion (1223) which is suitably arranged in order that, whenever this protrusion comes in contact with the control valve (9), the valve is enforced to open. The beginning of the opening of the control valve (9) occurs when the distance between the auxiliary rod (1220) and the main piston (12) is less than a prescribed limit which depends on the length of the activating protrusion (1223).

Ih figure 26d is shown an arrangement which offers an enhanced timing adjustability. In this case, the activating protrusion (1223) is seated on a protrusion spring (1224) which said spring lies between the protrusion (1223) and the auxiliary rod (1220). In this case, whenever the distance between the auxiliary rod (1220) and the piston (12) is less than a limit and, additionally, the moving protrusion (1223) comes in contact with the control valve (9), the control valve (9) will remain closed although the auxiliary rod (1220)

continues to move against the valve. When the force -which the protrusion (1223) applies to the valve- overcomes a certain limit, the valve will begin its opening. The aforementioned "limit" depends on the pressure difference between the working chamber (100) and the auxiliary chamber (100A) and (profoundly) is related, at any moment, to the amount of the momentary compression of the control spring (930). In the arrangement of the specific depiction, the amount of the momentary compression of the protrusion spring (1224) depends on the momentary distance of the main piston (12) from the extreme wall (11). At any other case, the contact of the protrusion (1223) with the valve (9) is not sufficient for the opening of the valve — except, of course, at the case where the compression of the protrusion springs (1224) is of a great magnitude.

It is understood that there are plenty of alternative arrangements (arising, profoundly, from elementary arrangements which are already presented) via which can be performed a satisfactory control for the time moment at which the control valve (9) begins to open.

All kind of the "state change" dampers which are proposed by the present invention can be utilized in arrangements of the technical level which are destined for the dynamic control of a vehicle body. Usually, these "smoothing' arrangements utilize freely suspended masses the motion of which is controlled by a combination of springs and energy absorption elements which provide subcritical damping. In figure 27a is shown, indicatively, a configuration where a mass (M) is oscillating at the end of a pivoting beam which is suspended by a spring (S) which is controlled by a damper (C). Said damper provides subcritical damping (i.e. for "smoothing" the vertical reactions of a vehicle which moves, with considerable velocity, over rough surfaces). In this case, it is suggested, according to the spirit of the present invention, that this configuration must be equipped, additionally, with an elastic, restrictive element (TR) which applies, around an equilibrium point, a temporary deceleration to the mass (M), followed by a temporary acceleration. This kind of restricting arrangement enables the piston, inside the damper, to achieve (temporarily) higher values of maximum velocity - and, profoundly, to perform a more intense cavitation of the damping fluid. The recovered energy from this arrangement (which is cooling energy, preferably) can be utilized to serve certain needs of the vehicle on which it is attached. In figure 27b is shown an arrangement which is relative to that of figure 27a with the difference that, in this specific application, the damper is of the "rotary type" resembling that of figure 17.

In figure 28 a is shown an arrangement which is dedicated to the separation of the gaseous from the liquid state of a fluid. This separation is performed, indicatively, via the oscillation of a mass (M) which is suspended from the top of a resilient pylon (776) which pylon undergoes an un-damped oscillation. More specifically, the device consists of a rotary damper of the "state change" type (similar to that of figure 17), which is fed with hydraulic medium via an inlet (EIS) and, also, said damper outflows gaseous state, separated from the liquid state, via an outlet (EX). In figure 28b is shown a combination of a rotary damper (3) and a pendulum having a certain mass (M) which are suspended from the top of an - attached on a buoy (777) - pylon (776). Via the certain arrangement, the production of desalinated water is feasible. In figure 28c is shown an arrangement

corresponding to that of figure28b, which is suspended on a pylon (776) of a floating carrier (777). Li this case, case, the pylon (776) is the mast of a floating vessel.

The technical level provides a variety of auxiliary damping arrangements -like that of figure 29- which are based upon the concept of "vertically oscillating free masses". The already known, from the technical level, arrangement of figure 29, produces an undamped frequency which is added (with the opposite sign) to an existing oscillation for which it is desirable to be damped. Profoundly, the arrangements of this type can be utilised more usefully in the case where they are combined with a "soft" damping which is provided from the devices which are proposed by the present invention.

In figure 30 is shown one such application of the operating principle of the present invention in a unit which possesses a vertically oscillating mass, between two springs. In this case the oscillating mass is the piston (12) of the damper, according to the present invention. This arrangement is feasible, par example, to be suspended from an oscillating body and, utilizing the oscillation, it can produce a gaseous state which is separated from the liquid - or, even to be used as a cooling device.

It is understood that, via a profound way, it is possible to create an unlimited variety of devices which, according to the present invention, can be transformed to an operational unit which separates the gaseous state from the liquid state of a substance. In figure 31, par example, is shown an arrangement where the piston of the damper (12) remains immobilized, according to a reference level, and the oscillating masses are the body (1010) of the damper and a second mass which operates (according to the hydraulic circuit which accompanies the certain embodiment) either as auxiliary piston or (as in the specific depiction), as the piston of a flow pump which feeds, the working chamber (100) with a liquid. In the same depiction, for simplicity reasons, the reference to all the peripheral substructure of valving, ducting, etc is omitted. As it can be seen in this exemplary depiction, it is feasible to supply the working chamber (100) with hydraulic medium whenever the momentary distance between the piston (12) and the flow pump piston (21) surpasses a predefined value. This can be performed via the collaboration between the outflow protrusion (2004) and a corresponding intrusion (2002).

In figure 32a is shown, indicatively (and as an example of the variety of different combinations which arises from the described elements of the present invention) an arrangement consisting of three oscillating (in collaboration) masses (Ml, M2, M3 - of which the Ml is the body (1010) of the damper) and which masses are connected to corresponding springs (Sl, S2, S3) of which the Sl is, preferably, un-damped. Between them, the masses form a series of chambers (A, B, C) which, according to the application, can be utilized as working chambers (as it is indicated according the chamber A, in figure 32b) or as flow pump chambers (as it is indicated for the chamber C, in figure 32b, in combination with a pressure chamber-9091). In compound cases like this, the optimum operation of a damper, of the "state change" type, is performed via the selection of the suitable elasticity coefficients for the springs Sl and S2 and the masses Ml, M2 and M3, for every type of liquid damping fluid which is utilized in the certain application.