Patent Application
20090314355
The invention relates to an explosively actuated, pressurized fluid isolation valve utilizing a gravity biased piston to pierce and clear a flow interruption diaphragm.
A squib valve as described herein refers to a fluid isolation valve that uses a small explosive device to actuate an internal piston that opens the valve. Conventional explosively actuated valves employ an in-line piston to pierce a flow interruption diaphragm. In order to rupture the diaphragm and allow fluid flow through the valve, such an in-line piston is designed to move axially within a portion of the fluid flow path. However, a problem with such a piston configuration is that it must be disposed within a portion of the fluid flow passage. After the piston has served its purpose of rupturing the diaphragm, the entire piston remains within the fluid passage. Accordingly, the piston remains as a significant obstruction to the fluid flow through the valve.
Additionally, in order to accommodate an in-line piston and explosive actuation elements, contemporary valves include a bend in the fluid flow path. In this way, the inlet and outlet ports of the valve are not connected by a straight fluid flow path. The fluid passage bend or elbow provides an access point for installing and servicing the piston and other elements. Unfortunately, such a bend can undesirably restrict or impede fluid flow.
Further, once the diaphragm is ruptured, it remains within the fluid flow path. As such, loose fragments of the ruptured diaphragm can potentially further obstruct or even once again completely block fluid flow through the valve. Consequently, loose fragments of the ruptured diaphragm remaining within the fluid flow passage can lead to an undesirable and potentially dangerous circumstance, making such valves unreliable.
Thus, it is desirable to provide an explosively actuated valve assembly which overcomes the shortcomings found in the art of valves as set forth above while also providing a relatively simple, low-cost design that is reliable and adaptable to suit many environments and applications.
The present invention includes a valve assembly having a fluid flow passage, a piston passage, a closure element and a moveable piston. The fluid flow passage extends from an inlet port to an outlet port. The piston passage transects and is oriented non-parallel to the fluid flow passage. The closure element interrupts fluid communication between the inlet and outlet ports. The piston being moveable within the piston passage between a first and second position, the piston including a head for opening the closure element wherein movement of the piston between the first and second positions enables fluid communication between the inlet and outlet ports.
Additionally, the piston movement can remove at least a portion of the closure element from the fluid flow passage. Also, the valve assembly can further include an explosive actuation mechanism for rapid actuation of the piston from the first position to the second position. The explosive actuation mechanism can be a squib. Also, the closure element can be a frangible diaphragm. Further, the piston passage can extend away from two opposed sides of the fluid flow passage. The head can include a retaining element for holding the removed portion of the closure element. The retaining element can include a spike for penetrating the closure element. Also, the head can include a shearing element for separating the portion of the closure element for removal.
Another aspect of the present invention involves a valve assembly including a fluid flow passage, a closure element and a moveable piston. The fluid flow passage extends from an inlet port to an outlet port. The closure element interrupts fluid communication between the inlet and outlet ports. Also; the piston moves between a first and second position. The piston includes a head for opening the closure element, wherein movement of the piston between the first and second positions enables fluid communication between the inlet and outlet ports. Further, the piston movement removes at least a portion of the closure element from the fluid flow passage.
Additionally, the valve assembly can further include a retention chamber for containing at least a portion of the head while in the second position. The retention chamber substantially disposed outside the fluid flow passage. Also, the portion of the closure element can be removed to the retention chamber. Further, the valve assembly can include a piston passage transecting the fluid flow passage, wherein the retention chamber is disposed at one end of the piston passage. The closure element can be a frangible diaphragm. The head can include a retaining element for holding the removed portion of the closure element. The retaining element can include a spike for penetrating the closure element. Also, the head can include a shearing element for separating the portion of the closure element for removal.
These and other embodiments, features, and advantages of this invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.
This invention pertains to an explosively actuated valve assembly that provides a piston assembly that does not significantly obstruct fluid flow through the valve once opened. Also, the valve assembly according to the present invention provides a straight fluid flow passage from the inlet to the outlet port. Further, the valve assembly is designed to remove all loose fragments of the ruptured diaphragm from the fluid flow passage.
With reference to the drawings,
The fluid passage 110 is designed to convey fluid in a straight through flow path 115 from an inlet port 112 to an outlet port 118. Preferably, the inlet port 112 is integrally formed in the upper housing 102 and the outlet port 118 is integrally formed in the lower housing 108. However, alternatively the upper and lower housings 102, 108 can be constructed from multiple housing segments that are secured to form elements similar to those shown. The straight through flow path 115 provides less resistance to flow through the valve 100.
The piston passage 120 intersects and is oriented non-parallel to the fluid passage 110. A piston 130 is moveably disposed along the central longitudinal axis of the piston passage 120. Preferably, the piston passage 120 extends away from the squib housing 150 substantially in a downward direction (toward the ground) upon installation. In this way, gravity will induce the piston 130 to remain in the open position, once the squib 160 is activated. The longitudinal extent of the piston passage 130 need not be perpendicular to the ground. As shown, the piston passage 120 preferably intersects the fluid passage 110 at an acute angle. This configuration provides a means of easily installing a diaphragm 140 within the intersection of both passages 110, 120. It should be understood that the design of the valve 100, particularly the orientation of the passages 110, 120, can be formed differently to suit a particular environment. Accordingly, the valve 100 can be formed so that the angle of intersection between the fluid passage 110 and the piston passage 120 is either smaller or larger than that shown.
An upper portion of the piston passage 120 is formed by the upper housing 102 and contains substantially the entire the piston 130 therein when the valve 100 is closed. A lower portion of the piston passage 120 is formed by the lower housing 108. The lowest portion of the piston passage is referred to as the piston head retention area 128. After the valve 100 is opened by firing the squib 160, at least the piston head 136 is preferably contained within retention area 128, thereby keeping the head 136 out of the fluid passage 110. Also, any sheared central diaphragm 145 material will also be removed from the fluid passage 110 and deposited in the retention area 128.
The piston 130 is designed to move from the position shown in
For ease of assembly, the piston shoe 132 is removeably secured to the piston shaft 135 by piston nut 134. Thus, during assembly the piston shaft 135 can be inserted through the piston stop central aperture 126 and the piston shoe 132 then added. As shown, the piston shoe 132 is seated on an upper portion of the piston shaft and secured thereto by a piston nut 134 which is threaded onto the upper end 133, thereby securing the shoe 132 to the shaft 135. Alternatively, the piston shoe 132 and piston shaft 135 can be integrally formed. However, for assembly purposed, the piston head 136 would then need to be removable from the shaft 135, such as through a threaded coupling.
The piston head 136 includes a spike 138 and shearing blades 137. The spike 138 is designed to pierce the diaphragm central portion 145, and the shearing blades 137 are designed to shear away a substantial amount of the central portion 145. Preferably, the shearing blades 137 are the sharpened leading edges of the outer perimeter of the cylindrical piston head 136. The spike 138 axially protrudes beyond the shearing blades 137, such that as the piston head 136 moves toward the diaphragm 140, the spike 138 preferably engages and penetrates the center of diaphragm 140 before the shearing blades 137 engages the outer edges of the central portion 145. In this way, after the spike 138 pierces the diaphragm, the shearing blades 137 tear through the outer edges of the central portion 145. Thus, substantially all material forming the central portion 145 is held on the spike 138, as it is removed from the passages 110, 120 and conveyed to retention area 128. Preferably, the leading face of the piston head 136 has a concave design for collecting and conveying any separated pieces of central portion 145 after they are sheared from the diaphragm. Thus, the piston head 136 maintains any separated pieces of central portion 145 from obstructing fluid flow through the fluid passage 110.
Preferably, the piston head 136 is made of a durable materials, such as those described above for the housings 102, 108. However, the design is not limited to any specific materials, but rather certain materials properties are preferred based on application parameters, such as the material composition of the diaphragm 140, what types of fluids, and the pressures and temperatures involved. Also, alternatively the piston passage 120 can be formed with a continuous or parabolic curvature. The piston 130 and particularly the piston stem 135 could be similarly curved to conform to such a curved piston passage 120.
The upper and lower housings 102, 108 are each provided with flanges 102a, 108a for securely coupling the two housings with the diaphragm 140 between. The two housings 102, 108 are preferably aligned to form straight and continuous inner passages 110, 120 that are both interrupted by the diaphragm 140. The diaphragm 140 is formed as a disc and is secured between the upper and lower housings 102, 108. The outer portions of the diaphragm 140 acts as a sealing ring and includes apertures for receiving retainers 105. Also, additional sealing or bonding agents or materials can be provided between flanges 102a, 108a for ensuring a proper seal between the two housing members 102, 108. Additionally, a frangible diaphragm central portion 145 is provided. The central portion 145 can be integrally formed with the outer portions of the diaphragm 140 or formed from separate pieces. The central portion 145 should be strong enough to remain intact before actuation of the piston, thus preventing fluid flow through the valve 100. Also, the central portion 145 is designed to rupture and shear away once acted upon by the piston head 136. The diaphragm is preferably formed from inorganic metallic elements, such as stainless steel or a stainless superalloy.
The squib housing 150 is secured to an upper end of the upper housing 102. Preferably, the upper housing 102 is provided with another coupling flange 102b upon which the squib housing 150 is secured with a fastener 155. The union of these two housings 102, 150 should maintain a good seal before, during and after the squib is activated. The squib housing 150 holds one or more squibs 160, which is coupled to a squib activation system (not shown). The squib burn rate, pressure and volume can be selected and/or adjusted to provide the required valve action.
Also, secured to the squib housing 150 is a frangible link 165 that holds the piston 130 in the position shown in
Generally, the squibs 160 are an explosive actuation mechanism that quickly releases a pressure wave. The squibs 160 can by any suitable electrically operable pressure source. Preferably, a squib 160 is a pyrotechnic device that may be mounted in the housing 150, and which, when activated, provides a pressure wave that forces piston 130 rapidly towards retention area 128 of lower housing 108. Alternatively, the squibs 160 could be a non-pyrotechnic device capable of quickly releasing sufficient pressure to properly actuate the piston 130. The pressure wave provided by the one or more squibs 160 may be of any predetermined magnitude according to the requirements of a specific device and the application thereof. An example of an electrically operable pressure source is described in U.S. Pat. No. 5,443,088 to Hoch et al. and incorporated herein by reference.
It should be understood that some or all of the outer housings 102, 108, 150 can be formed by more parts than that shown. Also, additional or redundant sealing elements can be employed, such as metal or rubber o-rings, spring wound rings, v-rings, welding or other known sealing elements and/or techniques.
While various embodiments of the present invention are specifically illustrated and/or described herein, it is to be understood that the invention is not limited to those precise embodiments and that various other changes and modifications may be affected herein by one skilled in the art without departing from the scope or spirit of the invention, and that it is intended to claim all such changes and modifications that fall within the scope of the invention.
