Instant-on vented tank valve with manual override and method of operation thereof

Abstract: The invention relates to an "instant-on" valve assembly incorporating a manual override, designed to be connected to a tank containing high pressure gaseous fuel, for example for use in a gas powered vehicle. The valve assembly and manual override allows the tank to be alternately closed off, vented, or allows the gas in the tank to bypass the instant-on valve. The instant-on valve assembly can be repaired or replaced without venting the tank. The instant-on valve assembly (8) has a main valve (16, 18) and a bleed valve. The main valve has a primary plunger (16), and a secondary piston (18) that opens and closes a main orifice (40). The bleed valve has a bleed valve stem (52) that opens and closes a bleed orifice (50) and is connected to the primary plunger (16). The main valve (16, 18) is slidably mounted within a housing (20, 32) and has a chamber (38) at one end and a zone (76) at another end. Both the zone (76) and the chamber (38) have access to high pressure gaseous fuel within the tank when the main and bleed valves are closed. High pressure gaseous fluid within the zone (76) can be drained when the bleed valve is fully open. Activation of a solenoid (24) displaces the primary plunger (16) which in turn displaces the bleed valve stem (52) to open the bleed valve. When the pressure within the zone (76) is sufficiently reduced, the pressure within the chamber (38) will cause the main valve to open by sliding into the zone. A spring (66) moves the main valve towards a closed position when the solenoid (24) is deactivated. Since the volume of the zone (76) is relatively small, the main valve opens within one second after the solenoid is activated.

Description: This invention relates to gas valves for use in vehicles powered by natural gas or other gaseous fuels and to a method of operation thereof. Such valves are connected to high pressure tanks that are utilized to open and close a passageway along which high pressure gaseous fuel flows from the tank to an engine of the vehicle in which the system is installed. It is known to have gas valves installed on high pressure tanks in motor vehicles. Some previous valves are described in U.S. Patent Nos. 5,193,580; 5,197,710; and 5,341,844 issued to Wass, et al. Since the solenoid on previous valves must overcome the high tank pressure, previous designs utilize a two-stage process in which a small "bleed" orifice is opened initially, the "bleed". orifice being connected to the downstream gas outlet passageway. With time, the pressure in the outlet passageway gradually builds up so that the pressure differential between the tank and the outlet passageway is greatly reduced. Ultimately, the pressure differential is small enough that the solenoid is able to unseat the main valve, thus allowing the high pressure gas from the tank to have full access to the outlet gas passageway. Tank pressures are typically in the range of 24.8 x 10 6 Pa (3600 psi) and can rise to much higher values under adverse conditions and a typical diameter for inlet and outlet passageways is around 0.85 cm (one-third of an inch) or larger. It is not unusual therefore to require a force of 136 to 181 kg (300 to 400 pounds) to be exerted in order to unseat the valve and allow gas from the tank full access to the outlet passageway. Some previous valves are mounted internally and, when the valve malfunctions, it is extremely difficult to make repairs, to vent the tank or to remove the gas pressure from the valve by shutting off the flow of gas from the tank to the valve. Further, if the valve fails, with some previous designs, the motor vehicle cannot be operated. Still further, with previous valves, there is a relatively large time lapse from the turning of the key until the starting of the engine as it can take the valve eighteen seconds or longer to fully open. The herebefore cited US-A-5 341 844 discloses a tank valve assembly with manual override for connection to a tank containing high pressure gaseous fuel. EP-A-753 695 (published 15-1-97) discloses an instant-on tank valve assembly with the features of claim 1 except the manual override. It is an object of the present invention to provide an "instant-on" solenoid operated valve assembly with a manual override where an instant-on valve can move from the fully closed position to the fully open position in a fraction of a second, said valve can be easily repaired without having to remove said valve from the tank if it fails, the pressure can be easily relieved in a controlled manner from said valve if said valve fails, and the tank can be easily vented if said valve fails or the instant-on valve can be bypassed to operate the engine. It is a further object of the present invention to provide an instant-on tank valve assembly with manual override wherein the main valve opens within one second after a solenoid is activated to open a bleed valve. According to one aspect of the present invention, there is provided an instant-on ventilated tank valve assembly with manual override for connection to a tank containing high pressure gaseous fuel, said valve assembly and manual override comprising in combination: (a) a main valve, said main valve having a secondary piston slidably mounted within a housing to open and close a main orifice. The piston has a zone located at one end thereof and a chamber located at another end thereof. The secondary piston slides into said zone to open said main orifice. Said zone has an interruptable access to high pressure gaseous fuel, said chamber being accessible to high pressure gaseous fuel. There are means to interrupt said access to said gaseous fuel and means to drain gaseous fuel from said zone when said bleed valve is sufficiently open. The main valve opens when a pressure within said chamber sufficiently exceeds a pressure within said zone by said secondary piston sliding into said zone; (b) said manual override in the passageway for connection to said tank being connected to alternately close off said tank or vent said tank if said instant-on valve assembly is not operating properly. According to another aspect of the invention, there is provided a method of operating said instant-on valve assembly with manual override connected to a tank containing high pressure gaseous fuel, said method comprising setting the manual override in a neutral position and operating said instant-on valve assembly, when said instant-on valve assembly fails, moving the manual valve from said neutral position to one of a closed position or a venting position, thereby closing off a supply of fuel from said tank or venting said fuel from said tank respectively. In the accompanying drawings: Figure 1 is a partial sectional side view of the valve and override embodying the present invention; Figure 2 is an enlarged sectional side view of the instant-on valve of Figure 1; Figure 3 is a partial sectional view of the valve of Figure 1 mounted on a tank; Figure 4 is a partial, perspective, exploded view of a tank, a valve body and various hose and pressure line connections constituting the main components of a fuel supply system including the valve embodying the present invention; Figure 5 is a partial, perspective, exploded view showing one mode of connection between the tank and the valve body; Figure 6 is a partial, perspective, exploded view showing another mode of connection (as shown in Figure 3) between the tank and the valve body; Figure 7 is a partial sectional view of the valve connected into vent galleries (typical in both modes of connection); and Figure 8 is a partial sectional view of the valve body connected to the tank in accordance with Figure 5. In Figures 1, 2 and 3 there is shown a main valve body 6 in section having an instant-on valve 8 and a manual override 10. Drilled into the main body 6 are an inlet passageway 12 and an outlet passageway 14. The drawing illustrates a primary plunger 16 and a secondary piston 18 which are slidably connected to one another in a manner to be described below and which are slidable within a sleeve 20 secured to a stop block 22, with a solenoid coil 24 of conventional construction being mounted about the combination of the sleeve 20 and the stop block 22. The solenoid coil 24 is located within a cover 25. Immediately below the solenoid coil 24 and firmly supporting the same, is a collar 26 having an internal thread which engages a suitable external thread on the main body 6 and which has an integral flange 30 extending inwardly to a location adjacent the sleeve 20. A nut 31 holds the cover 25 in the position shown in the drawing. The material of the collar 26 is ferro-magnetic, with the result that the flux lines of the magnetic field created by the solenoid coil 24 pass only through bodies having a portion lying to the solenoid coil side of the flange 30. In the condition shown in Figure 1, the magnetic flux lines engage only the primary plunger 16 because the secondary piston lies entirely beyond the plane of the flange 30 on a side opposite to the solenoid coil. The sleeve 20 has a base 32 located in a machined out recess of the main body 6. The base has external threads (not shown) that mesh with internal threads (not shown) of the main valve body 6. Also machined into the main body 6 is a further cylindrical recess 38 which is coaxial with the outlet passageway 14 and defines a frusto-conical valve seat 40, also coaxial with the outlet passageway 14. The secondary piston 18 has a closure portion 42 which closes the outlet passageway 14 when the secondary piston 18 is in its lowermost position. The closure portion 42 of the secondary piston also can support a ring seal (not shown) which would form an effective seal against the frusto-conical valve seat 40. The secondary piston is slidably mounted within a housing and moves outward to open and inward to close. Along a central longitudinal axis of the closure portion 42 is a cylindrical coaxial passageway 48, which necks down at an inner end thereof to form a "bleed" orifice. The "bleed" orifice communicates with a frusto-conical valve seat 50, which may be closed or opened by a conical free end 51 of a valve stem 52. The free end 51 is connected to an elongated cylindrical member 54 having a centrally located enlarged collar 56 thereon. An end 58 (opposite to the free end 51) is preferably threaded coaxially into a suitable opening in the primary plunger 16. The valve stem 52 is received by a cylindrical portion 62 of the primary plunger 16. The bleed valve moves outward relative to said secondary piston to open and inward relative to said secondary piston to close. A conical frustum 64 of the primary plunger 16 is located on the outer end of the cylindrical portion 62 and has a cylindrical gallery 65 at its peak, adapted to receive one end of a compression coil spring 66. The spring 66 provides the force external to the secondary piston. Returning now to the secondary piston 18, it can be seen to have an outwardly projecting flange 68, which has a loose tolerance within the cylindrical recess 38 and a generally cylindrical portion 70 in the vicinity of the valve stem 52. The cylindrical portion 70 has firstly a two-stage internal concentric bore 72, including two sections which have respective diameters slightly greater than respective outside diameters of the cylindrical portion 54 and the collar 56 of the valve stem 52. When the valve stem 52 is in a closed position against the seat 51, the collar 56 is spaced away from a reduced section 73 of the bore 72. Due to the deliberate provision of the loose tolerance between the cylindrical portion 70 and the base 32 of the sleeve 20, high pressure gaseous fuel can find its way into a space 76 between the primary plunger 16 and the stop block 22. This takes place as follows: Firstly, the high pressure gas entering along the inlet passage 12 has direct access to the cylindrical recess 38. Due to the loose tolerance between the cylindrical portion 70 and the base 32 of the sleeve 20, the high pressure gas enters this annular space but cannot proceed past O-ring 80. The gas passes from the annular space just described to the bore 72 through passageway 82 and along the outer edges of the valve stem 52 through the bore 72 to annular chamber 84 located between the primary plunger 16 and the second piston 18. (The passageway 82 is represented by a broken-line circle in Figs. 1 and 2 since it extends at right angles to the plane of the Figures and is hidden behind the valve stem 52). The high pressure gas can travel through the bore 72 to the annular chamber 84 as the collar 56 is spaced apart from the reduced section 73. Once the gas reaches the annular chamber 84, it passes along the outside surface of the cylindrical portion 62 of the primary plunger 16 (which also has a loose tolerance with respect to the sleeve 20) and fills the space 76 up to a pressure substantially equal to the tank pressure. Gas from the annular chamber 84 also passes through eccentric but axially aligned bores 86 to reach a central cylindrical chamber 88 surrounding a free end 51 of the valve stem 52. What has been described thus far is an instant-on valve embodying the invention in the "static" or closed position when the solenoid coil 24 is not energized and the vehicle (not shown) is at rest with the key (not shown) in the "off" position. When the solenoid coil 24 is energized (preferably, by turning the key [not shown] to the "on" position), the primary plunger 16 will be pulled toward the stop block 22 against the force of the coil spring 66. Since the gas pressure surrounding the primary plunger 16 at the moment that the solenoid coil 24 is energized is equal around the primary plunger, there will be little resistance to the movement of the plunger (except for the pressure exerted by the spring 66). As soon as the primary plunger 16 starts to move toward the stop block 22, the valve stem 52 will move along with the primary plunger to open the small "bleed" orifice in the passageway 48 of the secondary piston 18. High pressure gas immediately passes through the "bleed" orifice through the passageway 48 and into the outlet passageway 14. The entry of gas into the passageway 14 plays no part in the control of the instant-on valve 8. The primary plunger continues to move toward the stop block 22 until the collar 56 is seated against (not shown) the reduced section 73 of the bore 72 to close the bore 72 to the passage of gas, thereby preventing high pressure gas from continuing to enter the annular chamber 84. As a result, the high pressure gas in the space 76 and all around the outside of the primary plunger 16 passes downwardly through the bores 86, through the "bleed" orifice and ultimately through the passageway 48 to the outlet passageway 14. The O-ring 80 is mounted in an annular gallery 90 in the cylindrical portion 70 of the secondary plunger 18. As stated previously, the O-ring 80 prevents high pressure gas from passing along the outside of the cylindrical portion 70 past the O-ring 80. The sealing effect of the O-ring 80 defines a differential pressure plane. As the high pressure gas from the area of the primary plunger 16 drains through the bores 86, the downward pressure on the secondary piston 18 quickly drops and a point is reached where the force lifting upwardly on the O-ring 80 (from the high pressure gas located in the annular space between the cylindrical portion 70 and the base 32) and the secondary piston 18 will exceed the downward force on the secondary piston 18 defined by the area of a circle having the diameter of the ring seal multiplied by the (quickly decreasing) pressure in the annular chamber 84. The space 76, chamber 84, annular space along an outer surface of the primary plunger 16 and outside part of the valve stem 52 to the collar 56 comprise a zone that is cut-off from-gas in the tank when the collar 56 seats against the reduced section 73. Since the zone has a tiny volume, pressure within the zone can be reduced quickly. Preferably, the main valve opens in less than a second after the solenoid is activated. When this state is reached, the secondary piston 18 will separate from the valve seat 40, thereby permitting the flow of high pressure gas directly from the inlet passageway 12 to the outlet passageway 14. When the secondary piston 18 has moved toward the primary plunger 16 so that part of the cylindrical portion 70 extends beyond the flange 30, the cylindrical portion 70 will be partially within the magnetic flux path created by the solenoid coil 24 causing a further attraction between the primary plunger 16 and the secondary piston 18. This attraction tends to further lift the secondary piston 18 away from the valve seat 40. As long as the engine (not shown) of the motor vehicle (not shown) is running, the secondary piston 18 will remain fully open. When the secondary piston 18 is moved toward the primary plunger 16 a sufficient distance, the free end 51 of the valve stem 52 will come into contact with the valve seat 50 at the "bleed" orifice, thereby preventing further movement of the secondary piston 18 toward the primary plunger 16. This will again open the annular passageway between the collar 56 and the reduced section 73 of the bore 72. The pressure differential across the O-ring 80 will therefore be reduced and will gradually progress toward equilibrium as more gas from the tank passes through the passage 82 and ultimately into the annular chamber 84 and the space 76. When the free end 51 of the valve stem 52 contacts the "bleed" orifice, the passageway 48 will be closed. At this stage, the primary plunger 16 will be in contact with the stop block 22 and the secondary piston 18 will be magnetically coupled to the primary plunger 16 and will remain in that position as long as the solenoid remains energized. The magnetic force is sufficient to resist the downward drag arising from the dynamic passage of the gaseous fuel between the passageways 12 and 14 and the force exerted by the spring 66. When the solenoid is turned off (i.e. the key) (not shown) or engine (not shown) is turned off, the force in the spring 66 is sufficient to move the primary plunger 16 away from the stop block 22, thereby initiating movement of the secondary piston 18 toward the closed position shown in Figure 1. It will be seen that the opening of the main access to the outlet passageway 14 is in no sense dependent upon the pressure in the passageway 14 as described in previously known valves. The outlet passageway 14 can be vented to the atmosphere through vent 93 without adversely affecting the operation of the instant-on valve assembly. The base 32 of the sleeve 20 has a screw thread on its outer surface (not shown) for receiving an annular body 94, which has a screw thread on its inner surface (not shown). Preferably, the sleeve 20 and base 32 are made from stainless steel and the annular body 94 is made from brass. Vents 96 located between the annular body 94 and the base 32 provide means to vent leaks to the atmosphere through passageways 98, 100, 102 in the event that any gas leaks past the O-ring 104. O-ring 106 is a static seal between the threaded union of the secondary piston 18. The O-ring 106 prevents high pressure gas from bypassing the intended path through passageway 82 that accesses space 84 via annular clearance of the secondary piston 18. O-ring 108 is a dynamic seal that prevents high pressure gas from flowing from the passageway 82 along the valve stem 52 after the enlarged collar 56 and reduced section 73 are in closed contact with one another. O-rings 110, 112 are secondary seals that prevent any leakage to an interior of the vehicle compartment should the high pressure O-ring 104 leak. An instant-on valve assembly constructed in accordance with the structure described above was able to move from the fully closed position to the fully opened position within an interval of 58 milliseconds. In addition to the instant-on valve 8, the valve of the present invention has the manual override 10 which can be utilized in place of the instant-on valve 8 to vent the tank or to bypass the instant-on valve to run the engine (not shown) and operate the vehicle (not shown) or, further, to shut-off the gas supply completely to the instant-on valve and the engine. As shown in Figure 1, the manual override 10 has an end cap 202 which is sealed by an O-ring 204 to prevent or at least reduce leakage in the event that the manual override 10 leaks. To operate the manual override, the end cap 202 must be removed to expose a head 206. The head 206 is connected to an elongated valve spindle 208. The valve spindle has two annular projections 210 thereon. The annular projections fit within a corresponding screw thread so that the spindle 208 will move inward when turned clockwise (when viewed from the head 206) and will move outward when turned to counterclockwise. In Figure 1, the manual override 10 is shown in the fully open position. In the fully open position, an enlarged inner end 212 is almost completely removed from the inlet passage 12 from the tank (not shown in Figure 1), thereby allowing gas from the tank to flow to the instant-on valve 8. In the fully open position, the enlarged end 212 rests against an O-ring 214 so that pressurized gas will not leak into an interior of the manual override 10. When the manual override 10 is turned clockwise so that it is partially closed (i.e. with a line 216 near the head 206 aligned with an outer surface 217 of the housing 218), the manual override 10 is in a bypass position. In the bypass position, when the instant-on tank valve is not functioning and is in a closed position, high pressure gas can flow from the tank (not shown in Figure 1) along the passageway 12 around the enlarged end 212 and into an interior 220 of the manual override 10. From the interior 220, the high pressure gas flows along a bypass passageway 222 into the inlet passageway 14 to the engine (not shown). In this manner, the engine can be operated even though the instant-on tank valve is inoperable. It should be noted that the size of the bypass passageway 222 is much smaller than the passageway 12 and the outlet passageway 14 so that a reduced amount of gas will flow through the passageway 222 in the bypass mode. When the head 206 is turned clockwise still further, the enlarged end 212 will seat against seat 224 of the inlet passageway 12 to completely shut-off the flow of high pressure gas from the tank (not shown) through the inlet passageway 12. In the bypass position, the manual override can be used to vent the tank instead of running the engine (not shown) of the motor vehicle (not shown). In the fully open position shown in Figure 1, the manual override 10 can be used to vent the tank through a pressure relief valve (not shown) in recess 250 which is connected to inlet passageway 12 through passageway 252. O-ring 254 prevents leakage through the interior 220 of the housing 218. Similarly, O-ring 256 located between washers 258 prevents leakage from the interior 220 to the head 206. If the O-ring 256 does leak, then O-ring 204 prevents leakage through the end cap 202. As shown in Figure 3, when high pressure gas from the tank 270 leaks along the outside of the valve body 6 through passageways 272, past O-ring 274, the gas is prevented from leaking out of the connection between the valve body 6 and the tank 270 by secondary seal 276. The gas leaks through passageway 278 to passageway 102 which vents to the atmosphere. Similarly, when gas leaks into an interior of the end cap 202, it is vented through vents 282, 284 and 286 to the vent passageway 102 and to the atmosphere. In Figures 3, 4, 5 and 6, there is shown the tank 270 having an integral neck 290, which has internal threads 292. From Figures 5 and 6, it can be seen that the internal threads 292 are adapted to receive a threaded boss 304 extending integrally from the valve body 6. In Figure 5, the threaded boss 304 preferably has a tapered thread (sometimes called a "pipe thread"), and the internal threads 292 of the neck 290 are correspondingly tapered. It is known that a tapered thread connection becomes more and more impervious to leakage the more it is tightened, particularly when using sealing tape or the like. However, there always remains the risk of a thread abnormality or a crack in one of the two threaded members, which could allow high pressure gaseous fuel to escape. From Figure 3, it can be seen that any such escaping gas would first enter the annular space 20 between the top wall of the neck 290 and the outward step defined by the valve body 6. The annular space just described, in accordance with this invention, is sealed by the provision of a sleeve 306 which is attached by means of adjustable clamps 308. In Figure 6, the attachment of the valve body 6 to the tank 270 is the same as that shown in Figure 5, except that the sleeve 306 and clamp 308 have been omitted. In Figure 5, the tank is steel and in Figure 6, the tank is aluminum. Figures 4, 5 and 6 show the cover 25 having the nut 31 on the valve body 6. A further aspect of the present invention can be seen, especially in Figures 4 and 7, where it is evident that there are provided two venting hoses 310, each having one end 312 secured to the valve body 6 by fitting over a respective boss 314 such that the passageway or gallery aperture 102 and a high pressure opening 318 (to which respective feed line 320 is attached) communicate only with the interior of the respective venting hose 310. As best seen in Figure 7, the other end of each venting hose 310 is open to the atmosphere on the exterior of the vehicle. More particularly, the wall of the vehicle dividing the inside from the outside is shown at the numeral 322 in Figure 7. Secured to the wall 322, and passing through it, are three vent flange adapters 324, of which the outer two are connected respectively with the downstream end of the appropriate venting hose 310. If desired, a circular clamp 326 (see Figure 4) could be used to secure this connection. The function of the middle vent flange adapter 324 will be explained subsequently. It will be noted particularly in Figure 4 that the feed lines 320 remain inside their respective venting hose 310 to the downstream end, where the respective feed line exits. From the exit, the feed lines run to the engine of the vehicle. Thus, the feed lines 320 do not "break through" the wall of the respective venting hose 310, which means that there is no possibility of any leakage of gaseous fuel between the upstream connection of the venting hose to the respective boss 314 and the downstream connection of the venting hose to the flange adapter 324. Each of the vent flange adapters 324 has an integral annular flange 328 and is secured in place by a plurality of threaded fasteners 330 of known kind, which engage the wall 322. As best seen in Figure 7, the bottom end of each vent flange adapter 324 is truncated along an angle of approximately 45°, whereby the angular orientation of the vent flange adapter 324 can be selected so as to maximize the suction on the downstream end of the venting hose 310 when the vehicle is moving. Referring simultaneously to Figures 1, 4 and 7, either of two conventional pressure relief devices 332, 332a is adapted to be mounted in an opening 250 in the valve body 6, the opening 250 having an internal thread which engages an external thread on the pressure relief device 332. The opening 250 communicates along the passageway 252 with the interior of the inlet passageway 12. An O-ring (not shown) is provided for purposes of sealing. As will now be evident from an inspection of Figure 7, the pressure relief device 332, 332a is located within a venting hose 334 which fits over a suitable boss 336 and which has a downstream end secured to the third vent flange adapter 324. It is not the purpose of the venting hose 334 to contain the high pressure gaseous fuel in the event that the pressure relief device 332, 332a is activated. The containment of such released fuel is the task of a high pressure line 338, 338a and the appropriate connecting means. The function of the venting hose 334 is to conduct to the exterior of the vehicle any gaseous fuel that leaks out along the threaded connection between the valve body 6 and the pressure relief device 332, 332a. To provide further insurance against leakage into the interior of the vehicle in the event of a leak around the pressure relief device 332, 332a, there are provided two vent ducts 286 between the face of the boss 336 and the main vent gallery 102. Figure 8 is a partial sectional side view of an instant-on valve with manual override installed in a tank in accordance with Figure 5 with a sleeve 306 and clamps 308 surrounding the connection between the boss 304 and the neck of the tank 290. The same reference numerals have been used in Figure 8 as used in Figures 1 to 7 to describe the same components. While one embodiment of this invention has been illustrated in the accompanying drawings and described hereinabove, it will be evident to those skilled in the art that changes and modifications may be made therein, without departing from the scope of this invention as defined in the appended claims.

Claims: An instant-on vented tank valve assembly (8) with manual override (10) for connection to a tank (270) containing high pressure gaseous fuel, said valve assembly and manual override comprising in combination: (a) a main valve, said main valve having a primary plunger (16) slidably connected to a secondary piston (18), said secondary piston (18) being slidably mounted within a housing to open and close a main orifice (14), said secondary piston having a zone (84) at one end and a chamber (38) at another end, said secondary piston (18) sliding into said zone (84) to open said main orifice (14), said zone (84) having an interruptable access to high pressure gaseous fluid, said chamber (38) being accessible to high pressure gaseous fuel, with means (56, 73) to interrupt said access between said zone (84) and said gaseous fuel, means (48, 51) to drain gaseous fuel from said zone (84) to reduce pressure within said zone (84), said main valve opening when pressure within said chamber (84) sufficiently exceeds pressure within said zone (84) and said secondary piston slides into said zone (84); (b) said manual override (10) being connected in the passageway (12) for connection of said valve assembly to said tank (270) to alternately close off said tank or vent said tank if said instant-on valve assembly is not operating properly. A valve assembly with manual override as claimed in claim 1, wherein said means to drain gaseous fuel from said zone is a bleed valve located within said secondary piston, said bleed valve having a bleed valve stem (52) that is slidable within said secondary piston (18) to open and close a bleed orifice, access between said zone and said high pressure gaseous fuel being open when said valve stem is closed or partially open, said access being closed when said valve stem is fully open, said means to drain gaseous fuel from said zone being at least one outlet between said zone and said bleed orifice, gaseous fuel draining from said zone through said bleed orifice when said valve stem is fully open, said valve stem closing said bleed orifice when said main valve opens. A valve assembly with manual override as claimed in claim 2, wherein said bleed valve stem (52) is connected to a solenoid (24) moving said valve stem to open said bleed orifice when said solenoid is activated. A valve assembly with manual override as claimed in claim 3, wherein said solenoid (24), when activated, moves said main valve to a fully open position and holds said main valve in said fully open position after said main valve has been opened by a pressure differential between said chamber and said zone. A valve assembly with manual override as claimed in claim 4, wherein said main valve has a spring (66) biased to move said main valve towards a closed position when said solenoid is deactivated. A valve assembly with manual override as claimed in claim 5, wherein said manual override (10) is connected to include alternately a bypass of said valve assembly. A valve assembly with manual override as claimed in claim 1, wherein said valve assembly has (a) an inlet passageway (12) and an outlet passageway (14); (b) said means to drain gaseous fuel from said zone being a bleed valve, said bleed valve having a bleed valve stem (52) mounted to move relative to said secondary piston (18) to open and close a bleed orifice, said main orifice and said bleed orifice providing access to said outlet passageway, said zone having open access to said tank (270) through said inlet passageway when both of said valves are closed so that said zone has a pressure substantially equal to a pressure of said high pressure gaseous fluid within said tank, said zone being isolated from said access to said tank when said bleed valve opens by a sufficient amount, said zone having a drain to drain pressure from said zone when said zone is isolated from said access, said main valve opening when said pressure on said inner portion from said chamber is sufficiently greater than a pressure on said outer portion from said zone, said bleed valve providing means to interrupt said access between said zone and said gaseous fluid, said bleed valve being connected to open when a solenoid (24) is activated, said main valve closing when said solenoid is deactivated, said secondary piston being biased towards a closed position by a force external to said secondary piston, said zone having said open access to said gaseous fuel within said tank when said bleed valve is closed. A valve assembly with manual override as claimed in claim 7, wherein said secondary piston (18) moves outward to open and inward to close and said bleed valve moves outward relative to said secondary piston to open and inward relative to said secondary piston to close, said secondary piston being slidably mounted within a housing. A valve assembly with manual override as claimed in claim 8, wherein said bleed valve is located within said secondary piston and said bleed valve is closed when said main valve is fully open. A valve assembly with manual override as claimed in claim 9, wherein said solenoid (24) is connected to move said secondary piston outward when said main valve is in an open position until said bleed valve is in a closed position and to assist in holding said secondary piston in an open position until said solenoid is deactivated. A valve assembly with manual override as claimed in claim 10, wherein said force external to said secondary piston is a spring (66). A valve assembly with manual override as claimed in claim 11, wherein said manual override is connected to include alternately a bypass of said valve assembly. A valve assembly with manual override as claimed in claim 12, wherein said bleed valve is centrally mounted within said secondary piston (18). A valve assembly with manual override as claimed in claim 13, wherein said bleed valve stem (52) is loosely mounted within said secondary piston so that gaseous fluid can flow around said secondary piston to said zone when said bleed valve is not fully open relative to said secondary piston. A valve assembly with manual override as claimed in claim 14, wherein said bleed valve stem (52) has a shoulder (56) thereon that abuts a corresponding abutment (73) on said main valve when said bleed valve is fully open to isolate said zone from said gaseous fuel within said tank to prevent gaseous fuel from continuing to flow into said zone. A valve assembly with manual override as claimed in claim 15, wherein said drain is at least one outlet from said zone to said bleed orifice. A valve assembly with manual override as claimed in claim 16, wherein said outlet is connected to drain said gaseous fuel from said zone through said bleed orifice to said outlet passageway beyond said main orifice. A valve assembly with manual override as claimed in any one of claims 7, 9 or 16, wherein said zone has a very small volume, said zone becoming sufficiently depressurized so that said main valve opens in less than a second after said solenoid (24) is activated. A valve assembly with manual override as claimed in claim 17, wherein said bleed valve stem is mounted within a frustrum (64) that moves outward when said solenoid (24) is activated to contact a stop block (22) within said solenoid, said spring (66) being mounted between said stop block and said frustrum. A valve assembly with manual override as claimed in claim 19, wherein said frustrum (64) has a conical shape at an end adjacent to said stop block (22), said stop block having a corresponding interior conical shape to receive said frustrum, said spring (16) being mounted at an outer end of said frustrum. A valve assembly with manual override as claimed in any one of claims 7, 8 or 9, wherein said manual override (10) has an end cap (202) sealed by an O-ring (204) to at least reduce leakage of gaseous fuel into the atmosphere in the event that said manual override leaks. A valve assembly with manual override as claimed in any one of claims 7, 8 or 9, wherein the manual override (10) has an elongated valve spindle (208) with a head at an outer end thereof, said valve spindle having two annular projections (210) thereon, said annular projections being sized to fit within a corresponding screw thread in a housing surrounding said spindle so that said spindle will move inward when turned in one direction and outward when turned in an opposite direction, said manual override having a fully open position when said spindle is turned outward to allow gaseous fuel to flow to said valve assembly, said manual override having a fully closed position when said spindle is turned fully into an inlet passageway to said valve assembly to close said passageway, said manual override having a bypass position intermediate said fully open and said fully closed positions to permit gaseous fuel to flow from said tank directly into said outlet passageway, thereby bypassing said instant-on valve assembly. A valve assembly with manual override as claimed in claim 8, wherein there is a seal (80) between said secondary piston (18) and said housing, said seal preventing gaseous fuel from passing between said piston and said housing past said seal. A method of operating an instant-on valve assembly with a manual override (10) according to any one of the preceding claims, said valve assembly with manual override being connected to a tank (270) containing high pressure gaseous fuel, said method comprising setting the manual override in a neutral position and operating said instant-on valve assembly, when said instant-on valve assembly fails, moving the manual valve from said neutral position to one of a closed position or a venting position, thereby closing off a supply of fuel from said tank or venting said fuel from said tank respectively. A method as claimed in claim 24, which includes, when said instant-on valve assembly fails, moving said manual valve to an intermediate position whereby said manual valve is moved to an intermediate position, thereby permitting gaseous fuel to flow directly from said tank to an outlet passageway of said valve assembly, thereby bypassing said valve assembly. A method as claimed in claim 24, including the step of conducting repairs to said instant-on valve assembly when said manual valve is in the closed position. A method as claimed in claim 25, wherein said instant-on valve assembly has a bleed valve located within a secondary piston (18) of said main valve, said bleed valve having a bleed valve stem (52) to open and close a bleed orifice, said bleed valve stem being connected to open said bleed orifice upon activation of a solenoid, said method comprising activating said solenoid and opening said main valve within one second after activating said solenoid.

Inventors: KHADIM NEIL M, KHADIM, NEIL M.
Applicants: GFI CONTROL SYSTEMS INC, GFI CONTROL SYSTEMS, INC.
Application year: 1997
Main classification: F16K39
IPC codes: F02M21, F16K31, B60K15, F17C13, F16K1, F16K39