Background of the Invention Regulating and shut-off valves make up a considerable part of the equipment in modern industries, power plants, mineral extraction etc. Improvements in production processes and rising capacities of power plants have brought about increases in the parameters of working media, in particular flow rates, pressures and pressure differentials at which the valves operate. Since valve design has not substantially changed in recent decades, the aforementioned improvements result in considerably larger dimensions and weights of the valves, in larger power consumption, at the same time reducing their service life. Developments have been confined to improvements in the design of certain elements, in particular those that make the valves more leak-proof when shut, easier to manufacture, etc. But the properties that determine the power consumption needed for optimal control have remained unchanged. In the case of pipelines with large diameters and large pressure drops the equipment has become too bulky and too power consuming. As a result, such valves are very inertial and are characterized by long operating times. It should also be noted that the design of these valves does not provide for the required level of flow stability.

The problem of developing small-size equipment requiring a low-power drive intended for operation under hard conditions of large pressure drops is vital for heat and atomic power plants, space and aviation engines, chemical industries etc. One of the most urgent problems is to provide for normal operation of such valves in emergency conditions (for instance, when a complete loss of voltage at a heat power station makes an immediate cut-off of the fuel supply to the boiler burners imperative). Another important task consists in widening the functional capacities of valves, in particular, supplementing their regulating functions with shutting-off duties.

Analysis of the existing problems in hydraulic control equipment for high pressure and flow rate pipelines shows that development of a new valve capable to provide high hydraulic resistance (about 30-40 MPa and even more, if necessary) has currently become a crucial task. The market for such valves seems to be almost unlimited and includes the power industry, chemical technology, rocket and aviation engineering, gas and oil transportation, shipbuilding, etc.

Hydraulic control equipment working under high pressures are characterized by vibrations, flow rate pulsation, erosion of the operating unit, and noise, reducing the service life of the valve and raising the power consumption of its drive. To overcome these drawbacks a two-seat valve was designed (US patent 005244011A).

Unfortunately, the solution provided by such a valve is complex both in design and in manufacturing technology. Besides, the former valve is not effective enough in ensuring a uniform distribution of hydraulic resistance between the stages, which prevents the valve from functioning as a shut-off element.

Valves acting under large pressure differentials are known (US patent 4617963) in which the stream is divided into a number of small streamlets throttled by a single control element--the so-called cassette valve. But such a design does not ensure pipeline tightness when the valve is shut. Besides, with the use of such a design it is not easy to ensure the required level of the flow stability relating to the movement or turn angle of the control element.

In order to improve the cavitational characteristics a vortex chamber is built downstream from the outflow. The vortex chamber provides for effective transformation of bubble cavitation into developed cavitation, which precludes direct contact of pulsating and collapsing bubbles with the operating surfaces of the valve.

As a consequence, cavitation-induced erosion of the operating unit is also precluded, which prolongs the service life of the device and essentially reduces flow instability.

The use of vortex valves as a flow controller is known, when a common pressure source is used as the control signal and the pressure supply has been severely limited.

Vortex valves normally have at least one radial supply inlet and one or more tangential control inlets (US patent 4819431). If a single power source is available, an orifice retractor must be used in series with the supply flow to provide the working differential between supply and control pressures. The pressure differential across an orifice is at a maximum at the highest flow condition and at a minimum at the lowest supply flow level. Efficient operation of the valve as a flow controller requires the opposite: no control at maximum total flow, and therefore no pressure differential is required. At minimum total flow, maximum control flow and the largest pressure differential are desired. This undesired flow-pressure relationship severely limits the maximum flow turndown of the conventional vortex valve operating with a common pressure source.

The shortcomings-of this design of vortex valves are eliminated in the design of a valve with a vortex chamber equipped with two tangential ducts injecting the flows into the chamber in opposite directions (US patent 3674044, prototype). Such a valve functions without a controlling pressure, whose value, as shown above, must exceed the pressure of the main flow (the feeding flow) the rate of which is to be regulated.

The maximal flow rate of the fluid is realized when the flow rates through the tangential ducts become equal. Throttling one of the tangential ducts causes the moments of the flows entering the vortex chamber to be unbalanced, thereby inducing the swirling of the flow. While the presence of a tangential component in the flow velocity helps to improve the cavitational characteristics of the valve as well as the stability of the fluid parameters, there is an increase in resistance to the outflow through the outlet nozzle of the vortex chamber and a decrease in the total flow rate through the valve,. The minimal value of the flow rate through the valve is achieved when one of the tangential ducts is completely shut. The advantages of this regulating valve are: (a) the capability of functioning without a controlling flow with higher pressure than that of the main flow; (b) a smaller pressure differential on the controlling element, the value of the flow rate through which does not exceed 0. 5 of the total flow rate through the valve. Note the lower value of minimal hydraulic losses on the valve, because there is no need to throttle the entire flow in order to create a controlling flow with a larger pressure value. At the same time this valve has considerable drawbacks that restrict the field of its application.

The main disadvantage is primarily related to the value of the flow rate regulation range. Even with one of the tangential ducts completely shut the range of flow rate regulation does not exceed 3 to 3.5, whereas the solution of most tasks requiring the installation of regulating valves demands a regulation range of at least 20 to 50.

Besides, the considered valve does not provide for functioning as a shut-off valve with a high level of leak-tightness. As the controlling element is installed upstream to one of the tangential ducts, the latter receives the pressure differential between the inlet chamber of the valve and the side surface of the vortex chamber. The force resulting from the action of this pressure differential is conveyed to the pneumatic or electric drive that controls the position of the controlling element, and in view of the high values of this force the required power of the drive is also considerable.

The primary object of the present invention is to provide a vortex valve configuration which is capable of controlling the discharge flow rate with great flexibility while acting under large pressure differentials.

It is another object of the present invention to design a vortex valve with a shut-off capability.

It is another object of the present invention to design a vortex valve requiring low power consumption.

It is a further object to provide a vortex valve having a long service life. t Summary of the Invention In accordance with a preferred embodiment, the inventive vortex valve comprises: a) a valve body ; b) an inlet chamber; c) a fluid distribution chamber ; d) a vortex chamber ; e) two tangential ducts through which two opposing flows are injected from said fluid distribution chamber into said vortex chamber ; f) a displaceable control element installed at the inlet side of said tangential ducts comprising two throttling elements, each throttling element being actuable to reduce the flow rate through a different tangential duct ; and g) a means for imparting axial displacement to said control element differentially to actuate said throttling elements whereby to control the flow rate through said tangential ducts.

One of the tangential ducts of the vortex chamber is coaxial with the valve body, and the other duct is inclined at an angle to its axis. Both ducts serve to feed the fluid to the vortex chamber. The control element is disposed in the fluid distribution chamber and contains two integrally built throttling elements: a cylindrical bushing and needle-shaped valve head. The needle-shaped valve head is actuable to throttle the flow into the coaxial tangential duct. For controlling the flow rate entering the inclined tangential duct, a sleeve is utilized having ports that connect the fluid distribution chamber with the inclined tangential duct. The cylindrical bushing is disposed within said sleeve and is axially displaceable therein to effect throttling of the inclined tangential duct by incrementally covering said ports. The preset flow rate characteristics of the valve are achieved by the appropriate throttling of the ports in the sleeve and of the coaxial tangential duct. Throughout the description to follow the term valve body refers to the housing encompassing the inlet chamber, fluid distribution chamber and vortex chamber.

In one embodiment, the vortex valve, in order to function as a shut-off and to provide for a high level of leak-tightness when shut, is equipped with a gate produced with an integral driving rod being controlled by a pneumatic or electric drive. In another embodiment, the required force for the drive that controls the position of the control element is reduced by eliminating the need of a gate.

In order to further reduce the hydrodynamic forces acting on the control element and the required power of its drive, a preferred embodiment is disclosed in which the gate is made separate from the controlling rod and is equipped with a spring-loaded differential piston. A duct having a variable cross-section as the controlling rod is displaced therein connects a pressure reducing chamber that is also connected with the inlet chamber of the vortex valve.

During those operating conditions in which a constant high-pressure head at a maximal flow rate is applied to the vortex valve, another valve embodiment may be utilized comprising: a) a valve body; b) an inlet chamber; c) a vortex chamber; d) one tangential duct through which fluid flows from said inlet chamber into said vortex chamber; e) a displaceable control element installed at the inlet side of said tangential duct comprising a throttling element, said throttling element being actuable to reduce the flow rate through said tangential duct; and f) a means for imparting axial displacement differentially to actuate said throttling element whereby to control the flow rate through said tangential duct.

Brief Description of the Drawings The present invention will be more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: Fig. 1 shows a longitudinal sectional view of the vortex valve in an open position ; Fig. 2 shows a longitudinal sectional view of the vortex valve in an intermediate throttling position; Fig. 3 shows a radial sectional view of the control element cut about plane A-A of Fig. 1 ; Fig. 4 shows a sectional view of the vortex chamber cut about plane B-B of Fig. 2 and the way in which the outlet nozzle is installed therein with a flange for connection with the discharge pipeline; Fig. 5 shows a longitudinal sectional view of the vortex valve in a closed position ; Fig. 6 shows a longitudinal sectional view of another embodiment of the vortex valve in which the required force of an external drive is reduced; Fig. 7 shows an enlarged longitudinal sectional view of the needle-shaped valve head used in the embodiment of Fig. 6; Fig. 8 shows a longitudinal sectional view of an additional embodiment of the vortex valve further reducing the required force of an external drive employing a differential piston and a pressure reducing chamber in dual communication with the inlet chamber and the fluid distribution chamber. The elements are shown in an open position of the valve ; Fig. 9 illustrates a sectional view of the ribs connecting the piston housing with the valve body cut along plane C-C of Fig. 8 in one of which a tapered needle in inserted to create the throttling cross-section; Fig. 10 is a schematic diagram of the inventive system by which fluid pressure is lowered in the pressure reducing chamber ; Fig. 11 illustrates a sectional view of the piston housing construction in greater detail ; Fig. 12 illustrates the design of the outlet nozzle of the vortex chamber; and Fig. 13 shows a longitudinal sectional view of another embodiment of the vortex valve in which one tangential duct is utilized.

Detailed Description of Preferred Embodiments We refer now in detail to the drawings for the purpose of illustrating preferred embodiments of the present invention.

Fig. l illustrates a configuration of the vortex valve in which no swirling flow is existent. Vortex valve 1 comprises valve body 11 and vortex chamber 2 having two tangential ducts 3 and 4 that produce opposing flows in the chamber. Tangential duct 3 is coaxial with valve body 11 of the valve, and tangential duct 4 is positioned at an angle to the axis of valve body 11. The fluid enters fluid intake 16, flows through inlet chamber 20 and passes through fluid distribution chamber 31. A portion of the flow enters ports 13 and flows through inclined tangential duct 4 via collector 14 before entering vortex chamber 2. The remaining portion of the flow passes through tangential duct 3 before entering the vortex chamber. In this configuration the flow rates through tangential ducts 3 are 4 are equal, and therefore no swirling action is produced.

Figure 2 illustrates the vortex valve in an intermediate throttling position. Cylindrical control element 5 is located in fluid distribution chamber 31 and has two throttling elements that are actuable to reduce the flow rate. One of the throttling elements is needle-shaped valve head 6 located at the end of linkage 7 connecting control element 5 with gate 17. Valve head 6 is horizontally disposed and is actuable to reduce the flow rate through tangential duct 3. The other throttling element is bushing 8 connected with linkage 7 by ribs 9. Bushing 8 is actuable to reduce the flow rate through tangential duct 4 and is concentric with valve body 11. As shown in Figure 3, the fluid flows through annular clearance 27 formed between linkage 7 and the inside surface of bushing 8 to the tangential ducts of the vortex chamber.

Sleeve 10 is mounted within valve body 11, and bushing 8 advances along the inner surface of sleeve 10. Nut 12 prevents movement of sleeve 10 relative to valve body 11. Fluid penetration through the clearance between sleeve 10 and valve body 11 is prevented by gasket ring 28. An array of peripheral passage ports 13 through which the flow passes into collector 14 is formed on the cylindrical surface of the sleeve.

The fluid flows from collector 14 to inclined tangential duct 4 of the vortex chamber.

Seat 15 is provided on the inlet end of the sleeve.

Fluid intake 16 is connected to the inlet pipeline (not shown) by means of flange 22.

Gate 17 and controlling rod 18 are machined as an integral item. Controlling rod 18 is axially driven by a drive means (not shown). The surface through which controlling rod 18 penetrates valve body 11 is hermetically sealed by packing 19. Control element 5 is connected with gatel7 by head 21 of linkage 7 inserted within a recess made in gate 17. Outlet nozzle 29 of the vortex chamber (Fig. 4) is located in outlet pipe 30 equipped with flange 34 for connection with the discharge pipeline.

The valve functions in the following way: As controlling rod 18 is moved by the drive, control element 5 is axially displaced relative to the tangential ducts of the vortex chamber. For operating conditions at which the hydraulic resistance of the valve is minimal and the fluid flow rate is maximal for a given pressure drop, controlling rod 18 positions control element 5 so that the passageways of the fluid to the tangential ducts of the vortex chamber are completely open. In other words, the ports of sleeve 10 are uncovered and valve head 6 is retracted from the entrance to coaxial tangential duct 3 far enough to preclude the throttling of flow (Fig. l). This provides for equal flow rates through both tangential ducts and for the absence of flow swirling in the vortex chamber, thereby minimizing the hydraulic resistance of the valve.

When controlling rod 18 axially advances control element 5 and thereby throttles the flow through the valve, bushing 8 of the control element starts closing passage ports 13 in sleeve 10, while valve head 6 has not yet throttled the flow through coaxial tangential duct 3 (Fig. 2). This results in a reduction of the flow rate through inclined duct 4, while the flow rate through axial duct 3 remains unchanged. The amount of flow reduction through tangential duct 4 is a function of the configuration of ports 13 as well as the port surface area being covered. Deviation from flow rate equality between the two ducts introduces a tangential component into the flow velocity inside the vortex chamber and raises the hydraulic resistance to the outflow, leading to a reduction of the fluid flow rate through the valve. Further movement of the control element and decreasing areas of the passage ports in the sleeve raise the intensity of the flow swirl in the vortex chamber and its resistance to the outflow. When the outflow through nozzle 29 of the vortex chamber has a tangential component, the cavitational characteristics of the valve improve, vibration, noise and fluctuation in the fluid are minimized, stable flow rate characteristics are achieved, and the reliability and service life of the valve are increased.

After the passage ports of sleeve 10 are completely closed as shown in Figure 2, valve head 6 of the control element is located at the entrance to the axial tangential duct 3.

At this position of bushing 8, the flow rate through tangential duct 3 is maximal whereas there is no flow through tangential duct 4. As controlling rod 18 is further displaced in order to increase the flow rate regulation range, valve head 6 begins to constrict the flow through the axial duct. The fluid velocity at the vortex chamber is increased, thereby producing a higher hydraulic valve resistance and a lower flow rate. This pattern of throttling provides for any flow rate regulation range and precludes the development of cavitation in the axial duct due to the action of the hydraulic backwater created by centrifugal forces which result from intense flow swirl in the vortex chamber.

As the valve head throttles the flow through the axial duct, gate 17 settles on seat 15 of sleeve 10 (Fig, 5), hermetically separating fluid distribution chamber 31 from inlet chamber 20. Gate 17 and controlling rod 18 constitute the shut-off means for the vortex valve.

The required force for displacing controlling rod 18 and control element 5 may be reduced by eliminating the need for a gate. To compensate for the lack of a gate, gasket rings 25 and 26 are installed on bushing 8 as a sealing means. Gasket ring 25 is mounted on a peripheral groove machined on the inlet side of bushing 8 whereas gasket ring 26 is located downstream from throttling ports 13. Gasket ring 25 prevents the flow of the fluid to vortex chamber 2 through the clearance between bushing 8 and sleeve 10. Gasket ring 26 prevents any leakage from the inlet chamber into the vortex chamber through the clearance between the bushing and the sleeve after ports 13 are covered. Needle-shaped valve head 33 is provided with raised facing 23, as seen in greater detail in Figure 7, consisting of a narrow ring formed on the inlet side of valve head 33. Raised facing 23 is provided with an annular groove, and resilient seal 35 is mounted therein. When raised facing 23 rests on seat 24 on the inlet side of the axial tangential duct, complete sealing of fluid distribution chamber 31 from vortex chamber 2 is achieved. It should be noted that this design solution enables the force necessary for controlling the valve to be reduced by 5-6 times.

A preferred embodiment for force reduction is illustrated in Figure 8 in which the force required by the drive may be reduced tens of times. The driving force is maximal when gate 40 rests on seat 39 and receives the full inlet pressure. Gate 40, connected with control element 46 by linkage 49, is equipped with a spring-loaded differential piston 37. The differential piston is disposed within piston housing 38, the latter being connected by ribs 41 (Fig. 9) with valve body 42. Pressure reducing chamber 44, concentric to piston periphery 36, is connected with inlet chamber 45 of the valve through calibrated orifice 47 (Fig. 8). Preset throttling cross-section 52 (Fig.

9), alterable as controlling rod 43 advances, passes through one of ribs 41 and connects pressure reducing chamber 44 with the periphery of the vortex chamber 2.

In this embodiment controlling rod 43 is configured independently of control element 46. The extremity of controlling rod 43 is machined to form tapered needle 53 which, as the controlling rod advances, creates a regulated throttle cross-section with duct 52 (Figs. 8,9). At the given inlet pressure the pressure value in pressure reducing chamber 44 is determined by the relation between the areas of calibrated orifice 47 and of the regulated throttle cross-section 52, which will be explained below.

A schematic diagram of the hydraulic booster as implemented by spring-loaded differential piston 37 is presented in Fig. 10. The booster consists of orifices 47 and 52. Orifice 47 admits fluid at a high pressure from inlet chamber 45. Orifice 52 has a variable cross-section that is regulated by the movement of tapered needle 53. In pressure reducing chamber 44, which communicates with orifices 47 and 52, a pressure is produced whose magnitude for a given value of inlet pressure is determined by the relationship between the areas of the orifices and the magnitude of the outlet pressure. The magnitude of pressure in pressure reducing chamber 44 affects differential piston 37 in such a way that it axially displaces control element 46.

The force requirement of the externally disposed drive (not shown), whose function is to displace tapered needle 53 within duct 52, is significantly reduced since the latter has a diameter-of only 4-6 mm. Although a high inlet pressure is applied to orifice 47, the force required to control the position of needle 53, due to its small cross-sectional area, does not exceed 100-150 kg even at pressure levels within inlet chamber 45 in the order of tens of MPa. This force takes into account the frictional forces acting between controlling rod 43 and packing 57 (Fig. 9). The value of the pressure in pressure reducing chamber 44 is determined by the equation where P is the pressure in pressure reducing chamber 44, P ; n and Pex are the pressures at inlet chamber 45 and at the periphery of the vortex chamber respectively, and Fi and F2 are the areas of the orifices 47 and 52 respectively.

Differential piston 37 is loaded by spring 61 (Fig. 11). To prevent lateral forces from acting on the piston, spring plate 62 has a spherical support surface. Gasket rings 63 and 64 are mounted on the smaller and larger diameters of piston periphery 67, respectively. It should be noted that gasket 64 does not have to meet high retention requirements and is installed only for the stability of the hydraulic characteristics of pressure reducing chamber 44. Gate 40 is machined with curvature 66, which together with seat 39 formed on valve body 42 (Fig. 8) provides a shut-off capability for the valve. Openings 50 in gate 40 connect fluid distribution chamber 55 with spring chamber 54 of the differential piston. Piston housing 68 is constructed to be contiguous with piston periphery 67 on the upstream side, whereas cavity 56 is configured between piston housing 68 and piston periphery 67 on the downstream side to allow for the entry of the fluid.

After passing throttling cross-section 52 created by the retraction of needle 53 (Figs.

8,11), a portion of the flow goes through by-pass pipe 51 to the axial tangential duct.

This by-pass flow is subjected to the low pressure existent at fluid distribution chamber 55, i. e. at the periphery of the vortex chamber, when gate 40 is closed on seat 39. The low pressure is applied to pressure reducing chamber 44, and the pressure within the pressure reducing chamber is therefore dependent on the high pressure at inlet chamber 45 passing through orifice 47 and the low pressure at the periphery of the vortex chamber.

Due to the configuration of piston housing 68, high pressure fluid flows through inlet chamber 45, around differential piston 37 and gate 40, through radial spacing 58 and into cavity 56 in labyrinth fashion (Fig. 11). When needle 53 opens throttling cross-section 52, the pressure in pressure reducing chamber 44 and in neighboring chamber 60 is reduced. Radial ring 59, disposed on the downstream support surface of the differential piston between piston periphery 67 and piston housing 68, is coexistent with cavity 59 and with chamber 60, and the force caused by the pressure difference acting on radial ring 59 begins to axially displace differential piston 37 towards inlet chamber 45. Each position of controlling rod 43 corresponds to a definite position of differential piston 37 and of control element 46 connected thereto.

The actual position of control element 46 is determined by the equilibrium of forces acting on the movable elements of the valve.

When needle 53 closes duct 52, the pressure in pressure reducing chamber 44 becomes equal to the inlet pressure. Radial ring 59 is then equilibrated from static pressure forces. Since the surface area of gate 40 is larger than the area of radial ring 59, a hydrodynamic force caused by the flow helps move the differential piston towards seat 39, thereby closing the valve and preventing inflow to the vortex chamber. The piston operates by means of the compressive force imparted by spring 61 and by the hydrodynamic force provided by the influx of fluid into spring chamber 54.

It should be noted that the pressure in spring chamber 54 of the differential piston always corresponds to the pressure in the flow downstream of gate 40. Therefore the upstream cross-sectional area of the piston is always equilibrated from static pressure forces.

In operation, the stream exiting from the vortex chamber has a tangential component in its velocity, which affects the hydraulic resistance of the devices located downstream from the valve. To eliminate that influence ribs 70 are provided in outlet nozzle 71 of the vortex chamber (Fig. 12). Ribs 70 are radially disposed relative to the longitudinal axis of the chamber and divide the flow into several streams. In the absence of turbulent flow the ribs do not considerably affect the hydraulic resistance of the valve; their presence increases the resistance only with the appearance of a tangential component in the velocity, the growth of which raises the resistance further.

This innovation in the design results in higher efficiency of changing the flow rate characteristics of the valve according to the movement of the regulating element.

Thus, the proposed regulated vortex valve provides for any given flow rate regulation range having a drive with lower power requirements than existing valves and improved cavitational characteristics, and functions as a shut-off valve as well.

An additional embodiment of the vortex valve construction having a more cost-effective design with improved cavitational characteristics is illustrated in Figure 13. For functioning under the action of a constant high-pressure head at a maximal flow rate, the vortex valve may be provided with vortex chamber 74 having a single tangential duct 73 to effect a large pressure drop, eg. the discharge pressure of the vortex valve is no greater than half of its inlet pressure. Intense swirling flow is existent in vortex chamber 74 at any flow rate, i. e. as tangential duct 73 ranges from completely open to completely closed, and a control element consisting of needle-shaped valve head 76 is actuable to reduce the flow rate through the tangential duct. The simultaneous occurrence of intense swirling flow and a large pressure drop precludes the development of cavitation.

The fluid enters inlet chamber 77, passes through secondary chamber 78 before flowing into vortex chamber 74 via tangential duct 73. An external drive (not shown) displaces controlling rod 75, which in turn imparts axial movement to the control element. The control element is located in secondary chamber 78 and consists of needle-shaped valve head 76. Alternatively, the valve head may be of a different contoured shape, depending on the required flow characteristics. Linkage 79 connects controlling rod 75 and valve head 76 by linkage connection means 80. As valve head 76 advances, the flow rate through tangential duct 73 is reduced. The flow velocity within vortex chamber 74, having only a tangential component, is consequently increased, thereby raising the intensity of the swirling as well as the hydraulic resistance therein.

Valve head 76 is provided with raised facing 81, consisting of a narrow ring, on the inlet side thereof. Raised facing 81 is provided with an annular groove, and resilient seal 83 is mounted therein. When raised facing 81 contacts seat 82 formed on the inlet periphery of the tangential duct, the fluid is prevented from flowing from secondary chamber 78 into vortex chamber 74. While this valve configuration is presented as a simple and cost effective application for usage with one tangential duct, any of the aforementioned configurations for reducing the required driving force, viz. one with a differential piston or one wherein the controlling rod is provided with a gate for prevention of leakage, may be implemented as well.

While embodiments of the invention have been described by way of illustration, it will be understood that the invention can be carried out by persons skilled in the art with many modifications, variations and adaptations, without departing from its spirit or exceeding the scope of the claims.