The present invention relates to a dual-function valve for supplying a container holding powder or fluid with a gaseous propellant and for discharging the contents of the container by means of a gaseous propellant without the contents of the container having to remain under pressure while stored.

Powders and fluids stored in containers may be forced out of the containers when there is higher pressure in the container than in the surroundings so that the contents are forced out of a riser having its aperture near the bottom of the container. Many fluids have a vapor pressure at ambient temperature which is sufficient to expel the fluid from the container .

For fluids having a low vapor pressure and for powders a gaseous propellant must be used, for example nitrogen, C0 ₂ , compressed air, pyrotechnical byproducts (squib charges) or mixtures of various gases. For many uses it may be un- desirable that a gaseous propellant under pressure is in direct contact with the contents of the container while stored. The gaseous propellant may be soluble in the contents of the container and give the contents undesirable characteristics. A gaseous propellant that iε dissolved in a fluid may lead to the formation of a two-phase flow, viz. , a gas phase and a liquid phase, in the tube network for discharging the contents of the container. This may lead to great problems in connection with the discharge.

This is particularly relevant in connection with fire extinguishing media which replace halon of various kinds. Halon installations are widely used, but are being phased out because of their detrimental effect on the environment. Halon belongs to the chemical group of halogenated hydrocar- bonε which are known to have certain environmentally undesirable aspects. Halogenated hydrocarbons generally have a very strong greenhouse effect, and it breaks down the ozone

layer which protects against ultraviolet radiation. As a result of this a resolution was adopted in the Montreal protocol demanding a general ban on the installation of new halon systems simultaneously with a phasing out of existing halon systems.

Halon is used as a fire extinguishing medium in installations for manual and/or automatic release. Halon in liquid form is stored in tanks of various sizes. At the release of the fire extinguishing equipment halon is conveyed through a tube system to nozzles and sprayed out in areas where fire is to be extinguished or prevented. Halon 1301, which is a widely used halon, has a vapor pressure at normal ambient tempera¬ ture of about 15 bar. It therefore turns into gas form immediately after leaving the nozzles, but may be kept chiefly in a liquid phase within the tube system.

Halon will partly be in gas form above the liquid surface in the storage tank. However, the pressure this generates is not always adequate to expel halon through the tube system sufficiently fast and completely. The storage tank is therefore normally pressurized by a gaseous propellant to a pressure that is higher than the vapor pressure of the halon, apart from the fact that large halon systems may have external injection of gaseous propellant during discharge.

After the adoption of the Montreal protocol , great efforts have been made to find substances capable of replacing halon in such fire extinguishing installations. However, one has not succeeded in developing substances which have the same physical properties as halon in said fire extinguishing installations, and which at the same time are exempt from other undesirable effects. Accordingly, the replacement substances have different physical properties.

One of the halon substitutes of greatest current interest is FM 200 from Great Lakes Chemicals. However, FM 200 has a

vapor pressure at ambient temperature which is even lower than halon 1301, viz. about 5 ar. This entails that the dependence on tanks pressurized with gaseous propellant such as nitrogen is even greater for such fire extinguishing media as FM 200 than for halon.

One of the greatest problems arising from replacing halon with FM 200 and similar substances is that nitrogen or other gaseous propellants dissolve in the fire extinguishing medium 0 when subject to high pressure. At the release of the equipment the extinguishing medium flows out through the tube system wherein the pressure is lower than in the tank, resulting in the dissolved nitrogen or other gaseous propellant leaving the solution. Gas pockets will then be 5 formed in the tube system, leading to complex two-phase currents in the tube network. The result thereof is that the extinguishing medium is prevented from flowing freely in the tubes and that less of the fire extinguishing medium is thus expelled per time unit. This problem is much less pronounced 0 with regard to halons since they do not require such large amounts of gaseous propellant in order to provide the desired operating pressure.

A number of producers have tried to solve this problem by ' increasing the size of the distribution tube network, adding special solutions for capturing the gas in the distribution network, etc. These are solutions which are feasible in new systems, at a certain additional cost, but which lead to almost prohibitive costs when halon is exchanged for ° replacement substances in existing systems.

A premature release of such a container, i.e., before the desired pressure has been reached, may have adverse effects.

5 if a fluid, such as a fire extinguishing medium having a vapor pressure above atmospheric pressure is having a disproportionately low operating pressure, this may cause the

formation of two-phase currents and thereby gas pockets and disturbances in the flow situation.

In order to prevent the gaseous propellant from being dissolved in the fire extinguishing medium, and the vapor pressure from sinking below a critical level during the discharge of the container, extra gaseous propellant is added in certain systems, including halon systems, subsequent to the release of the equipment. These present solutions are

10 large-scale, costly and complicated.

The same problem, i.e., how to prevent a gaseous propellant from being dissolved in a fluid while stored in order to avoid difficulties when discharging the fluid, is relevant ■ to other fluids as well.

It is thus a primary object of the present invention to solve in a simple and economically feasible manner said problems connected with a gaseous propellant operated

2° discharge of containers holding fluids and particularly replacement media for halon. A further object is to provide solutions which make possible the replacement of halon by alternative fire extinguishing media without requiring large, costly and time-consuming replacements of the whole fire 5 extinguishing system.

According to the present invention, these objects are accomplished by means of a valve for a container for powder or fluid, where the valve comprises a valve housing having an

'° inlet for the powder or fluid, preferably connected to a discharge tube, and an outlet for the powder or fluid, where a piston is mounted in an interior cavity of the valve housing so as to be displaceable in the longitudinal direction of the valve between two end positions, and where

5 the piston in one end position blocks the flow of powder or fluid between inlet and outlet whereas the piston in its other end position unblocks the flow, said valve being

characterized in that the valve further comprises an inlet for supplying a gaseous propellant to the container and that the piston is displaced from the position in which it blocks the flow to an open position in response to the pressure of the gaseous propellant at the inlet for the gaseous pro¬ pellant.

The invention will now be explained by reference to the enclosed drawings wherein

10

Figure 1 is a longitudinal section of an embodiment of the valve according to the invention, in a closed position.

Figure 2 is a longitudinal section of the same embodiment as '5 shown in Figure 1, in an intermediate position.

Figure 3 is a longitudinal section of the same embodiment as shown in Figure 1, in an open position.

o Figure 4 is an exploded longitudinal section of the em¬ bodiment shown in Figures 1, 2 and 3.

Figure 5 is a diagram of a typical fire extinguishing system including a valve according to the present invention. 5

Figure 6 is a longitudinal section of another embodiment of the valve according to the invention, in an intermediate position.

o Figure 7 is a longitudinal section of a variant of the embodiment shown in Figure 6 but having a resilient member, in a closed position.

Figure 8 is a longitudinal section of a variant of the 5 embodiment shown in Figure 1 but having a resilient member, in a closed position.

Figure 9 is a variant of the embodiment shown in Figure 1 , having a fluidization channel for powder use.

Figure 10 is still another embodiment of the present valve, in an intermediate position.

Figure 11 is a variant of the embodiment shown in Figure 10, having fluidization channel for powder use.

ιo Figure 12 is a perspective view of a partly cut-through model of the embodiment shown in Figure 10.

The valve according to the invention is shown in various embodiments which have a somewhat different design based on '5 the same technical idea.

All valves are constructed with an external housing 11 having an interior, preferably rotation-symmetrical cavity 24, an inlet 10 for gaseous propellant, an outlet 20, mean;- for 0 connection to the container 1, and preferably a bottom piece 16.

The housing 11, the center portion 14 with; a cir.tral tutx 1 r and optionally the bottom portion Hi art f ^' lxt t. ly et ι r< c . <■ 5 each other so that they constitutt ar. <>ρt ra: i\ι ur.lt. Η.t central tube 15 and the center port n r. 14 an preft ra l _. v produced in one piece, but may also bι produced ir: two parts which, for example, may be screwed together. The central tube 15 is preferably cylindrical having a diameter which is less than that of the cavity 24, the central tube 15 and the cavity 24 having coinciding axes. The center portion 14 may be screwed firmly into the housing 11 and the bottom portion 16 by bolts 18, as shown in Figure 1, tightly fitted together and locked with a locking ring 26, as shown in Figure 6, or 5 screwed together as shown in Figure 10.

The discharge tube 3 is secured to the center piece 14 by pressure, screws, etc. so that the bore 27 becomes a natural extension of the cavity of the discharge tube 3. The central tube 15 is closed at the top, but one or more center outlet(s) 23 are formed through the tube wall in approxima¬ tely the same height as the outlet 20 of the housing 11.

The piston 12 is the only movable part of the valve and moves in the longitudinal direction of the valve in the interior cavity 24 of the housing 11. The piston 12 is preferably cylindrical and has a rotationally symmetrical central chamber 22, the diameter of which is adapted to the central tube 15. The outer diameter of the piston 12 is largely adapted to the inner diameter of the interior cavity 24 so that no gas can pass between the exterior of the piston and the inside wall of the housing when the piston 12 is in its upper position. The gaskets, for example in the form of 0- rings 19, give additional seal against gas leakage. When the piston 12 moves downward to the other end position, parts of the piston 12 enter an area where the inner diameter oT the cavity 24 is greater than the diameter of the piston or where there are hollows 25. Tht out lct(s ' lit* o! tht channel(ε) 13 for gaseous propellant is art pl tt c 11. tht outside wall of the piston 12 ir: thi; area. Th» |':IM C S propellant which enters through lr.lt ! H tar M.< r< by f low through the channel(ε) 13 for gaseous ρroρ< l iar.: , through tht outlet 26, through the space betweer. tht piston \ 2 and housing 11, through the bore 17 and down into the container 1 above its contents 2.

The embodiments of the valve shown in respectively Figure 1, and Figures 6 and 10 show two methods for achieving this. In the embodiment shown in Figure 1 the piston 12 has the same diameter through its whole length so that the space between the piston and housing is obtained by an extension of the diameter of the interior cavity 24. In the embodiment shown in Figures 6 and 10 both the piston 12 and the cavity 24 have

approximately the same diameter through most of their length. However, on top of the valve the cavity 24 and piston 12 have smaller diameters adapted to each other so that a gas flow between the cylinder wall and the wall in the housing is prevented. When the gaseous propellant entering through the inlet 10 moves the piston 12 downward, this part of the piston enters the area of the cavity 24 that has a larger diameter so that the propellant gas can flow as described above. 0

When the contents 2 of the container 1 are a fluid having sufficiently high vapor pressure, this pressure, communicated through bores 17, will press against the bottom surface of the piston 12, moving the piston upward until the piston 5 strikes against the inside surface of the top of the valve housing. If the contents 2 do not have sufficient vapor pressure, for example when the contents of the container 1 is a powder or a fluid having low vapor pressure, the piston is pressed toward its upper, i.e. , closed position, by a 0 resilient member 28, shown in Figures 7 and 11 , for example a spring, such as a coil spring.

At this end position of the movement of tht* piston, tht piston 12 closes the outlet 20 in that the piston wall cuts ' off the connection between the center out It t 2 'Λ and out It t 20. In addition, it also shuts off gas flow through inlet 10 by the fact that one or more outlet(ε) 26 of the gaεeouε propellant channel(s) 13 in the piston (12) bear(ε) against the inside wall of the valve housing 11. In other words, o when the piston is in this position the valve is closed for flow both through inlet 10 and outlet 20.

When the valve 4 is released, the inlet 10 is opened for the gaseous propellant, preferably nitrogen. The pressure of the gaseous propellant against the top of the piston presses the piston down in opposition to the pressure of the contents of the container and/or force of a resilient member 28. The

resilient member 28 may occupy the position shown in Figure 7 or may be located on top of the central tube 14 of the central chamber 22.

When the piston is moved down inside the valve, the outlet(s) 26 is/are also moved down along the inside wall of the valve housing 11. When the piston enters the position where the flow space between the inside wall of the valve housing and the outlet(s) 26 opens up because the diameter of the interior cavity 24 has increased either round the whole periphery or In separate cavities formed by hollows or extensions 25, the gaseous propellant is able to flow down along the piston to the hollow or extension 25, a circumstan¬ ce which opens up for flow of gaseous propellant from inlet 10, through the channel for gaseous propellant 13, into the space between the central tube 15 and the valve housing 11, through the bore 17 and to the interior of the container 1. The gaseous propellant then flows into the container 1 and supplies operating pressure in the container 1. The piston 12 is moved further down by the gaseouε propellant until it strikes the center piece 14. On the way down toward this position, the outlet 20 is opened as the piston outlet 21 gradually opens the connection between the center outlet 23 and outlet 20. When the piston 12 strikes the center piece 14 the piston outlet 21 is aligned with the center outlet 23 and outlet 20. In this position both the inlet aperture 10 and the outlet aperture are open at their maximum for supply of gaseous propellant, respectively, discharge of contents. The valve does not close again until the gaseous propellant is shut off, either because the tank 7 of gaseous propellant is empty or because the release valve 8 is closed.

The hollow or extension 25 may either be hollows adapted to the radial positioning of the outlet(ε) of the gaseous propellant channel(s) 13 or be a more general extension of the diameter of the central chamber 22, shown in the drawings .

By adjusting the interdependent positioning of the outlet(s) of the gaseous propellant channel 13 and the piston outlet 21 and by adjusting the friction between piston 12 and valve housing and central tube 15, it is possible to ensure that sufficient gaseous propellant is passed down into the container before outlet 20 is opened. In this way it is possible to ensure that sufficient operating pressure has accumulated in the container 1 before the outlet 20 is opened, i.e. , a pressure sufficient to force the fire extinguishing medium from the container 1, up through the discharge tube 3 and valve 4, out through outlet 20 and into the distribution network 5 and nozzles.

Figures 2, 6 and 10 show embodiments of the valve in the intermediate position, where the valve is open for gaseous propellant through aperture 10 but where outlet 20 still is closed. The piston does not stop in this position, but the time elapsing from the depicted intermediate position until the outlet 20 is opened is sufficient for the gaseouε propellant to flow from tank 7 of gaseouε propellant and accumulate the necessary pressure above the contents 2 in the container 1.

The shown and preferred embodiments of the valve shown in the drawings have a cylindrical valve housing 11 where alεo the central chamber 22 and the piston 12 is cylindrical. In order to ensure that the valve is not adversely influenced by the fact that the piston rotates in the central chamber 22, it is preferred that the center outlets 23 be connected by means of tracks 29 encircling the exterior of the central tube 15, and that the piston outlets 21 be connected by means of tracks 30 which similarly encircle the piston. Likewise, the outlet 26 of the gaseous propellant channel 13 may be designed as an annular track, and the bores 17 be connected with tracks 33 ensuring that the gas from the gas channel may flow freely to the bores 17.

Obviously, it may also be arranged so that the piston outlet 21 will align with outlet 22 and the center outlet 23, and that the gaseous propellant channel 13 will align with the bore 17 by means of control devices mounted in the longitudi¬ nal direction of the valve on the piston 12 and either the central tube or the inside wall of the valve housing 11.

By an appropriate selection of the flow area for the gaseous propellant, I.e., the gaseous propellant channel 13 and the bores 17, the present valve will also function as a reduction valve and thereby ensure that the operating pressure of the installation will be correct.

Furthermore, the present valve may also be used to modulate the flow from the container by means of the pressure from the gaseouε propellant. By an appropriate selection of flow area dimensions and the resilient member 28 a reduction in the pressure of the gaseous propellant will immediately raise the piston 12 somewhat above its lower position and thereby confine the area of outward flow. By a selection of the interdependent embodimentε of the overlapping outlet apertures 20, 21 and 23, the response of the valve to such a regulation of gaεeouε propellant preεεure might be preεet both for providing a linear and a non-linear reεponεe to the outward flow in relation to regulations of gaseous propellant preεsure.

Powder, such as a fire extinguishing powder, may be difficult to force through a tube, particularly since it will become more compact while stored. It may be desirable or necessary to fluidize or stir up the powder before discharge. This may be carried out through a modification of the present valve, shown in Figures 9 and 11. The fluidization is here achieved in that a part of the gaseous propellant, for a brief period during the downward movement of the piston 12, passes from the gaseous propellant channel 13, through the fluidization

channel 31, into the center outlet 23, down the bore 27, and down through the discharge tube 3. This brief pulse of gaseous propellant ensures that the powder be fluidized so that it can flow out through the discharge tube and valve.

The fact that the present valve only has one movable part, the piston 12, reduces the possibility of malfunction and makes It simple and robust. The bottom part 16 of the valve may be omitted since the valve housing 11 may be secured directly to the container 1. However, the depicted em¬ bodiments are preferred for technical reasons related to production and use.

The connection between the outlet 20 and the external tube network may be effected by a direct coupling to the outlet or a rapid coupling as shown by coupling ring 32 and locking ring 34, shown in Figures 10 and 11.

Example - A fire extinguishing system utilizing halon sub- stitutes

Figure 5 showε εche atically the partε of a fire extin¬ guishing εyεtem where the valve according to the invention is used. The εystem correεpondε in its main features to a traditional halon εystem in which a gaseouε propellant, for example nitrogen, iε supplied, quite apart from the fact that such a traditional system iε continuously under preεεure from the container 7 of gaseous propellant. The tank 1 and the tube network 5 are the same as in a traditional halon system. The changed physical properties of the replacement medium, the alternative fire extinguishing medium, in relation to halon, will in general necessitate a replacement of nozzles 6, which is a simple and relatively inexpensive process and independent of the present invention.

The fire extinguishing medium 2 is poured into the container wherein it primarily exists in a liquid phase. The discharge

13 tube 3 extends from the valve 5 on the top of the container down to the fire extinguishing medium 2 and has its aperture near the bottom of tank 1. Under normal, non-activated, conditions the pressure in the container 1 is merely the pressure produced by the vapor pressure of the fire ex¬ tinguishing medium 2. This may vary depending upon the different media and the temperature. The vapor pressure of the fire extinguishing medium FM 200 is, for example, about 5 bar at 20°C. The pressure in the tank 1 is thus considerably lower than in a traditional halon installation, and reduces the possibility of losing fire extinguishing medium through leakage. However, this pressure is too low to ensure that the fire extinguishing medium iε expelled at εufficient velocity when the system is released, a circumstance which necessitates a supply of gaseous propellant.

A tank 7 of gaseouε propellant, preferably containing nitrogen, is under high pressure. The supply of gaseouε propellant from the tank 7 of gaseous propellant is regulated by the release valve 8, which can be released either manually or by remote control. At the release of the release valve 8 the gaseous propellant flows from the gaseouε propellant container 7 through the gaseous propellant line 9 through an opening in a valve 4, which iε a valve according to the invention. The gaεeouε propellant, which enters the inlet 10, preεεeε againεt the top of the piεton 12 and forces this down againεt the opposing vapor pressure of the contents of the container 1 and, optionally, a reεilient member 28. The valve 4 opens, aε described above, first for the gaεeouε propellant by the movement of the piεton down the valve 4. Thereafter the valve also opens for outlet 20 so that the fire-extinguishing medium is forced up through the discharge tube 3 and bore 27, out through outlet 20, into the dis¬ tribution tube network 5, and out through the nozzles 6.

By an appropriate selection of operating pressure for the gaseous propellant and by using nozzles 6 selected to suit

the fire extinguishing medium and the dimensions of the installation, it will be ensured that the fire extinguishing medium flows in a liquid state through the distribution network 5 to the nozzles 6 during most of the discharge period. Thereby a two-phase flow of gas and liquid through the distribution net 5 is avoided, as well as the above mentioned problems.

The fact that this fire extinguishing installation, except for valve 5 and nozzles 6, is like a traditional halon installation, also in its dimensions, means that the present valve advantageously may be used upon replacement of the fire extinguishing medium in an existing installation, and, similarly, that a new installation may be built without necessitating an increase in dimensions in relation to a traditional halon installation.

For other uses than that of a fire extinguishing installa¬ tion, the system will in its main featureε be set up aε εhown in Figure 5, but the distribution network and the nozzles will be replaced by a tube network that is adapted to the particular use.

A person skilled in the art will easily sec- that the present valve exists in more embodiments than those shown above. The design of channelε may vary from one area of application to another. In addition, the resilient member 28 may have a plurality of alternative positions.