Abstract:
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. The valve assembly can include an explosive actuation mechanism for rapid actuation of the piston from the first position to the second position.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to an explosively actuated, pressurized fluid isolation valve utilizing a gravity biased piston to pierce and clear a flow interruption diaphragm. 
         [0002]    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. 
         [0003]    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. 
         [0004]    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. 
         [0005]    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. 
       SUMMARY OF THE INVENTION 
       [0006]    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. 
         [0007]    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. 
         [0008]    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. 
         [0009]    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. 
         [0010]    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. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a cross-sectional view of a valve assembly in accordance with an embodiment of the present invention. 
           [0012]      FIG. 2  is a cross-sectional view of the valve assembly of  FIG. 1  in an actuated position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    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. 
         [0014]    With reference to the drawings,  FIG. 1  shows a cross-sectional view of a closed valve assembly in accordance with the present invention. The valve  100  is a squib actuated fluid isolation valve, herein referred to as a squib valve. The squib valve  100 , preferably includes a straight through fluid flow passage  110  that in the closed position is interrupted by a diaphragm  140 . The diaphragm  140  is designed to remain intact and prevent the possibility of flow through the squib valve  10  until the internal piston  130  is actuated. The piston  130 , once actuated by the explosive squib  160 , is designed to rupture the diaphragm  140 , thereby opening the valve  100 . A squib  160  is a pyrotechnic actuator, used to quickly move or propel piston  130 . To open the valve  100 , a signal is sent to the squib actuation system, thereby firing the squib  160  and driving the piston  130  to pierce and shear the diaphragm  140 , thereby allowing fluid communication between the valve inlet  112  and outlet  118 .  FIG. 2  shows the squib valve  100  in the open position. 
         [0015]      FIGS. 1 and 2  also show that the squib valve  100  includes an upper housing  102 , a lower housing  108  and a squib housing  150 . Preferably, the upper and lower housings  102 ,  108  are securely coupled and properly aligned to form two intersecting internal passages, namely the fluid passage  110  and the piston passage  120 . The upper and lower housings  102 ,  108  can be made from carbon steel or other durable materials suitable to the application. Similarly, oxidation and corrosion resistant materials, such as stainless steel or inconel can be used. The upper and lower housings  102 ,  108  are each provided with a coupling flange  102   a ,  108   a , for joining the two housings with the diaphragm  140  there between. As shown, the coupling flanges  102   a ,  108   a  are secured with fasteners  105 , preferably in the form of a bolt or screw. Alternatively, the outer elements can be joined through mating threads. However, a threaded mating configuration between the upper and lower housings  102 ,  108  preferably includes added features to ensure proper alignment of the two respective segments of the fluid and piston passages  110 ,  120 . For example markings on the outer housings can serve as alignment features. Also, the apertures for fasteners  105  can be asymmetrically configured to only align when the two housings are properly oriented. 
         [0016]    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 . 
         [0017]    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. 
         [0018]    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 . 
         [0019]    The piston  130  is designed to move from the position shown in  FIG. 1 , to the position shown in  FIG. 2 . The piston  130  preferably includes a piston shoe  132 , a piston shaft  135  and a piston head  136 . The piston shaft  135  passes through a piston stop  125  protruding from the inner walls of the piston passage  120 . Preferably, the piston stop  125  is integrally formed with the upper housing  102  and takes the form of a perforated disk that interrupts piston passage  120 . Particularly, the piston stop  125  includes a central aperture  126  which serves to guide the piston shaft  135  that passes there through. Both the central aperture  126  and the piston shoe  132  guide the piston  130  along a central longitudinal axis of the piston passage  120 . Once the squib is activated and the piston shoe  132  moves from position A toward position B, it is the piston stop  125  that limits further axial movement of the piston shoe  132 , and thereby the piston  130  itself. Additionally, the piston stop  125  is preferably provided with additional apertures  127  to avoid trapping air within the piston passage  120  on the squib-side of the piston stop  125 , which might otherwise inhibit movement of the piston  130  toward the a fully open position. Similarly, the piston shoe  132  is preferably provided with such apertures (not shown) to avoid the resistance that might otherwise be created as the piston shoe  132  moves away from the squib housing  150 . During actuation, as the piston shoe  132  moves, the volume  122   a  above the piston shoe  132  expands to a larger volume  122   b . It should be understood that the size and/or number of piston stop apertures  125  or piston shoe apertures can be altered or adjusted accordingly to suit the desired valve action. 
         [0020]    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. 
         [0021]    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 .  FIGS. 1 and 2  show a concave conical design for the lead/bottom face of the piston head  136 , however the concave depression can be formed as a cup or more non-symmetrical shape. 
         [0022]    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 . 
         [0023]    The upper and lower housings  102 ,  108  are each provided with flanges  102   a ,  108   a  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  102   a ,  108   a  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. 
         [0024]    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  102   b  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. 
         [0025]    Also, secured to the squib housing  150  is a frangible link  165  that holds the piston  130  in the position shown in  FIG. 1 . The frangible link  165  can be in the form of a frangible threaded bolt that passes through an aperture in the squib housing  150  and is threadedly secured to the top end of the piston shaft  135 . When commanded by a user or programmable interface, the squib actuation system sends a signal to fire to the squibs  160 . Thereafter, firing the squib  160  thus pressurizing volume  122   a  that causes a differential pressure across the piston shoe  132  and develops force sufficient to propel the piston  130  and brake the frangible link  165  holding the piston  130  in place. Also, the force drives the piston head  136  to rupture and shear the diaphragm central portion  145 , and deposit the sheared portion(s) in retention area  128 . Once the diaphragm  140  is breached, the fluid flow path  115  is opened allowing fluid to flow through the squib valve. Once the frangible link  165  is broken, the weight of the piston  130  will help maintain the piston head  136  in the retention area  128 . 
         [0026]    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. 
         [0027]    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. 
         [0028]    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.