WO2007056865A1

WO2007056865A1 - Valve assembly

Info

Publication number: WO2007056865A1
Application number: PCT/CA2006/001893
Authority: WO
Inventors: Mark Bishoff; Guy Bishoff
Original assignee: Mark Bishoff; Guy Bishoff
Priority date: 2005-11-18
Filing date: 2006-11-20
Publication date: 2007-05-24

Abstract

A valve assembly comprises a body and a passageway defined through the body. The passageway has a first end and a second end. A valve arrangement is positioned between the first end and the second end. The valve arrangement is movable between an open position in which the passageway is open and a closed position in which the passageway is closed. The valve arrangement is adapted to close the passageway in response to at lease two modes of failure.

Description

VALVE ASSEMBLY

Field of the Invention

The invention relates to a valve assembly for use in a connection between a source of fluid and a fluid recipient device .

Background of the Invention

Pipes, hoses and other flow lines can be used to connecc a source of fluid, for example an oil tank, to a fluid recipient device, for example a furnace. The connection generally includes adapters that connect fittings on a flow line to those on the oil tank and the furnace. When the connection is made between the oil tank and the furnace, the fluid, oil in this example, flows freely through the flow line from the oil tank to the furnace. There are circumstances in which the flow of oil may need to be interrupted. For example, the adapters may be sheared apart if hit, causing a leak. The flow line may rupture from the corrosive effect of the oil, or be otherwise break. It may be necessary to turn off the flow for maintenance in the absence of any failure of the connection.

Various shut-off valves are known m the art for closing a flow path. See for example U.S. Patent No. 4,449,545 to Vernor et al . which discloses a breakaway safety valve. The valve is adapted to break when the valve is subjected to a shearing force of predetermined magnitude. At the time of breakage, a valve member m the flow passage of the valve automatically closes to cut off fluid through the passage.

U.S. Patent No. 5,758,682 to Cain discloses a safety shuc off valve which has a circumferential area of weakness therearound so that if the body is severed along the area of weakness, a stop member is removed and a poppet is allowed to close to prevent fluid flow through the body.

U.S. Patent No. 3,575,195 to Alfien discloses a valve device comprising a piston controlled shutoff valve. The piston is spring biased to a valve-closed position and is moved against the spring bias to a valve-open position by normal operating pressure. A drop from normal operating pressure causes the piston to close the valve thereby isolating the faulty circuit.

U.S. Patent No. 2,608,205 to Proctor discloses an automatic safety valve closure system which includes a delivery pipe surrounded by a second pipe. The volume between the pipes is filled with an inert fluid for example water. If the delivery pipe is broken or springs a leak, the change in water pressure will cause the valve to close.

These and other known valves are configured to close in response to one mode of failure of the system they occupy.

Summary of the Invention

According to one aspect of the invention, there is provided a valve assembly comprising: a body,- a passageway defined through the body, the passageway having a first end and a second end,- a valve arrangement between the first end and the second end, the valve arrangement being movable between an open position in which the passageway is open and a closed position in which the passageway is closed; wherein the valve arrangement is adapted to close the passageway in response to at least two modes of failure.

According to another aspect of the invention, there is provided a valve assembly comprising: a body; a passageway defined through the body, the passageway having a first end and a second end; a valve member between the first end and the second end, the valve member being movable between an open position in which the passageway is open and a closed position in which the passageway is closed; a biasing means for biasing the valve member towards a closed position; a stop means for holding the valve member in an open position against the biasing means; and a sealable chamber maintainable at a fluid pressure without continuous external actuation; wherein, the valve member is adapted to close the passageway in response to a change in the fluid pressure.

According to still another aspect of the invention, there is provided a valve assembly comprising: a body comprising a breakaway valve and a shut-off valve; a passageway defined through the body, wherein the passageway has a first end and a second end; the breakaway valve connected between the first end and the second end wherein the breakaway valve as adapted to close the passageway when broken; and the shut-off valve being connected between the first end and the second end wherein the shut off-valve is adapted to activate in response to a change in fluid pressure.

According to a further aspect of the invention, there is provided a valve assembly comprising at least two valves connected in series by a conduit portion wherein the valves are adapted to activate in response to a change in fluid pressure in the conduit portion.

Brief Description of the Drawings

Preferred embodiments of the invention will now be described with reference to the attached drawings in which: Figure 1 shows a cross sectional view of a valve assembly according to an embodiment of the invention in a closed position;

Figure 2 shows a cross sectional view of the valve assembly of Figure I in an open position,-

Figure 3 shows an exploded view of the valve assembly of Figure 1 with the valve body shown in cross section,-

Figure 4 shows a perspective view of the valve assembly of Figure 1 with the valve body, an outer adapter and an inner adapter shown in cross section;

Figure 5 shows a cross sectional view of a valve assembly of Figure 1 in a closed position taken alone a vertical plane at right angles to the cross sectional view of Figure 1 ; Figure 6 shows a cross sectional view of a valve assembly according to another embodiment of the invention,-

Figure 7 shows a cross sectional view of a valve assembly according to a further embodiment of the invention;

Figure 8 shows a cross sectional view of a valve assembly according to a still further embodiment of the invention;

Figure 9 shows a cross sectional view of a valve assembly according to still another embodiment of the invention; and

Figure 10 shows a cross sectional view of a valve assembly according to yet another embodiment of the invention.

Detailed Description of the Preferred Embodiments Referring to Figures 1 and 2, a valve assembly 10 comprises a body 12 having a passageway defined therethrough between a first end or inlet 64 to a second end or outlet 66. Within the body 12 there is ball 46 which functions as a valve member movable between an open position (Figure 2) and a closed position (Figure 1) . The valve assembly 10 also includes a biasing means, for example a spring 48, which biases the ball 46 towards the closed position. A stop means, including upper and lower pistons 20 and 24, a piston rod 44 and a lower chamber 98, which is adapted to hold the valve member in an open position against the biasing means.

The valve assembly 10 is adapted to connect to a. fluid source at the inlet 64 through a neck 91. Similarly, the valve assembly 10 is adapted to connect to a fluid recipient device through an outer adapter 14 and an inner adapter 16 at the outlet 66.

In operation, the valve assembly 10 is connected between a source of fluid at the inlet 64 and a fluid recipient device at the outlet 66 while in the closed position depicted in Figure 1. The chamber is sealed by connection, for example, to a line which is adjacent to the flow line from the valve assembly to the fluid recipient device. The chamber, including the lower chamber 98 is then pressurised, for example with a gas, which pushes the stop means upward to the position shown in Figure 2, moving the valve member to the open position to allow fluid to flow through the passageway. The valve assembly may be pressurised in any number of ways, for example, through a snifter valve which allows pressurised gas to be injected into the chamber. The assembly does not need to be subject to continuous external actuation once charged.

If the valve assembly 10 is broken at the neck 91, the chamber will be depreεsurised, and the biasing spring will close the ball valve, thereby closing the passageway. Similarly, if a line connected to the outer adapter 14 or a flow line connected to the inner adapter 16 is ruptured and the flow line is at a lower pressure than the chamber, fluid pressure will be lost in the lower chamber 98 causing the valve member to close the passageway.

The body 12, the inner adapter 16 and the outer adapter 14 of the valve assembly 10 are described in more detail below. In this embodiment, the inner adapter 16 is a straight hollow tube. The outside of the inner adapter 16 is generally cylindrical but may include wrench flats 97 (see Figure 3) which allow the inner adapter 16 to be held by a wrench and screwed into the body 12. The outlet 66 of the inner adapter 16 has internal threads 99 which allow the inner adapter 16 to be screwed to a flow line. The opposite end of the inner adapter IS haa external threads 83 which allow the inner adapter 16 to be screwed to the body 12. The interior of the inner adapter 16 defines an interior passageway 81.

The outer adapter 14 is also generally tubular with a hollow cylindrical interior. The outer adapter 14 has two sets of external threads 72 and 74. The external threads 74 are for screwing the outer adapter 14 into the body 12. The external threads 72 are for screwing the outer adapter 14 to an outer line surrounding the flow line. Wrench receptacle 70 is aligned with and spaced inwards from the external threads 72. The wrench receptacle 70 allows the outer adapter 14 to be gripped by a wrench for screwing the outer adapter into the body 12 (see Figure 4) . Two o-rmg seals 18 encircle the outer adapter 14 adjacent and outer end 79. The o-rin g seals 18 are inaet in recesses around the circumference of the exterior of the outer adapter 14 and facilitate a fluid tight seal between the outer adapter 14 and the outer line.

The inner adapter 16 and the outer adapter 14 are each depicted as a separate component from the body 12 to facilitate manufacturability and assembly. The inner adapter IS and the outer adapter 14 may alternatively be machined from or cast with the body 12. The connections can be other than threaded, for example the flow line and/or the outer line may be clamped directly to the body 12. The adapters may be made of metal, for example copper, or a composite substance and may be flexible. The inner adapter 16 and the outer adapter 14 are not limited to the tubular shapes depicted in Figures 1 to 5 ,

The valve assembly includes a chamber and a passageway internal to the body 12. The passageway allows fluid to flow from the inlet 64 to the outlet 66.

Progressing from the inlet 64, the passageway includes an upper passageway 82. In the embodiment of Figures 1 to 5 the upper passageway is depicted as having a cylindrical shape but may have other shapes . The diameter of the upper passageway 82 is greater than the diameter of the ball 46 so that fluid may flow through the upper passageway 82 around the ball 46.

The bottom of the upper passageway 82 connects to an angled passageway 84. The angled passageway 84 is cone shaped to provide a valve seat. The diameter of the bottom of the angled passageway 84 is smaller than the diameter of the ball 45. When the ball 46 is seated in the angled passageway 84, as in Figure 1, no fluid can flow past the ball 46. The shape of the valve member or ball 46 and the angled passageway 84 need not be of circular cross section and may be varied as long as the valve member is movable to close the passageway. A narrowed passageway 86 extends downward from the bottom of the angled passageway 84. The narrowed passageway 86 is cylindrical with a diameter equal to that of the outlet of the angled passageway 84. Again, this particular shape of the narrow passageway is not essential. The narrowed paaaageway 86 joins the piston cylinder 88. The piston cylinder 88 is circular in cross section and shaped to fit the upper piston 20 as will be described in greater detail below. The interior passageway 81 of the inner adapter IS is connected to the piston cylinder 88 through a short horizontal passageway 77 which extends from the side of the piston cylinder 88. Thus a passageway comprised of the upper passageway 82, the angled passageway 84, the narrowed passageway 86, the piston cylinder 88 , the horizontal passageway 77 and the interior passageway 81 extends from the inlet 64 to the outlet 66.

The body 12 also incorporates a series of interconnected channels or chamber sections which are normally isolated from the passageway. An upper chamber section 80 extends parallel to the narrowed passageway 86. The upper chamber section 80 extends past the neck 91 of the body 12. As can be seen in Figures 1 to 5, the body 12 is narrowest at the neck 91 and the material thickness of the body 12 is thinnest between the outside surface of the neck 91 and the upper chamber section 80 to create a preferred fracture zone. The upper chamber 80 is sealed from the piston cylinder 88 by a plug 62. The plug 62 is press fit into the end of the upper chamber 80 after the upper chamber 80 is machined into the body 12. Rather than a single cylindrical channel, the upper chamber 80 may comprise multiple chambers positioned around the narrowed passage 86, may be one continuous chamber encircling the narrowed passage 86 or may be omitted.

A horizontal chamber extends outward from the bottom of the upper chamber 80. The horizontal chamber comprises a channel 109 interior to the body 12, a horizontal chamber section 107 defined between the body 12 and the inner adapter 16 and an adapter chamber 76 defined between the inner adapter 16 and the outer adapter 14- As best seen in Figure 4 the horizontal chamber is cylindrical and spaces the inner adapter 16 from the outer adapter 14 so that there is no direct contact between the two adapters. This is not essential. "The chamber, for example may be limited to a narrow channel, for example channel 109, adjacent to the inner adapter 16 along its whole length.

An advantage of at least a section of the horizontal channel completely encircling the inner adapter 16 is that when this configuration extends to the flow line and the outer line, any break in either may close the valve. The closure will occur as long as the fluid pressure internal to the outer line is higher than the fluid pressure external to the outer line. For example, when the valve assembly is operated in an atmospheric environment, the fluid pressure in the outer line is charged to a pressure higher than atmospheric pressure so that any break m the exterior of outer line will cause fluid to leak from the chamber the pressure to drop in the chamber. Similarly, the fluid pressure in the outer line is charged to a pressure higher than operating pressure in the flow line so that any break between the flow line and the outer line will cause fluid to leak from the chamber and the pressure to drop in the chamber.

In this embodiment, an angled channel section 108 extends downwardly at an angle from the horizontal chamber section 107. The angled channel section 108 connects to an angled recess 106. The angled recess is part of the piston assembly The piston assembly includes from the piston rod 44 downwards, the upper piston 20, a diaphragm 22, a diaphragm washer 34, the lower piston 24, a packing spacer 36, a belleville washer 40 and a base retaining ring 42.

The top surface of the upper piston has a hole 101 into which the piston rod 44 is press fit. The top surface of the upper piston also has a channel 104 for receiving an override rod 93. The outer circumference of the upper piston 20 has a protrusion 105 which has a diarreter sized to match tne diameter of the piston cylinder 88. There is a hole in the bottom of the upper piston 20 for receiving a shaft of a screw 32

The diaphragm 22 ia circular, flexible and has a hole in the middle to receive the screw 32. The diaphragm 22 also has a thick rim 102 around its circumference. The diaphragm waaher 34 is flat and ring shaped and sized to fit into a cylindrical hole below and of greater diarreter than the piston cylinder 88.

The lower piston 24 has an inverted cup shape with an outwardly extending shoulder 94. The outer diameter of the shoulder 94 is larger than the inner diameter of the diaphragm washer 34. The lower piston 24 has a hole through the middle to receive the shaft of the screw 32

The packing spacer 36 is cup shaped. Four recesses extend around the circumference of the packing apacer 36 for receiving o-ring seals 38. Two channels 96 are formed horizontally through the packing spacer 36 from the exterior to the interior. Two of the o-rmg seals 38 are above the channels 96 and two of the o-rmg seals 38 are below the channelB 96. The inner cup shape of the packing spacer 36 defines a closed bottom chamber 98. The chamber 98 is cylindrical and has an internal diameter equal to the external diameter of the lower piston 24.

Below the packing spacer 36 are the belleville washer 40 and the base retaining ring 42. As can be seen in Figure 3, the base retaining ring 42 is not a complete ring. There is a break in the ring 42 which allows the ring 42 to be flexed inward then expand back to its normal diameter to fit into a recess cut into the body 12- The ring 42 thus positioned will hold the piston assembly in the body 12. The belleville washer 40 is ring shaped with an upward angle. The belleville washer 40 has a spring action which presses up on the packing spacer 36.

The piston assembly fits together as follows. The piston rod 44 is press fit into the hole 101 in the upper piston 20. The upper piston 20 is inserted into the piston cylinder 88. A barbed insert 26 is inserted into the hole 101 in the bottom of the upper piston 20. The diaphragm 22 is inserted below the upper piston 20, The rim 102 of the diaphragm 22 is inserted into a recess 92 which extends around the top surface of the cylindrical hole in tne body 12. The diaphragm washer 34 is inserted below the rim 102 of the diaphragm 22. The lower piston 24 is inserted below the diaphragm washer 34 and the holes of the upper piston 20, the diaphragm 22 and the lower piston 24 are aligned. A flat washer 28 and a lock washer 30 are placed over the shaft of the screw 32 and the screw 32 is screwed into the barbed insert 26 to hold the piatons 20 and 24 and diaphragm 22 together. The connection is fluid tight so that no fluid can move through the centre hole in the diaphragm 22.

The packing spacer 36 is inserted and held in place by the belleville washer 40 and the snap ring 42. The lower piston 24 slides within the lower chamber 98. The diaphragm washer 34 holds the rim 102 of the diaphragm 22 in the recess 92 in a fluid tight manner.

There is a piston cavity 100 defined around the pistons 22 and 24. The piston cavity 100 is sealed from the piston cylinder 88 but may be in fluid communication with the lower chamber 98. Similarly a lower cylinder 103, below the protrusion 105 of the upper piston 20 is sealed from the lower chamber 98 but may be in fluid communication with the upper cylinder 88.

The lower chamber 98 is in fluid communication with the other chambers in the body through the angled recess 106, the two channels 96 and the angled chamber section 108. As can be best seen in Figures 3 and 4, the angled recess 106 forms a channel around the outside of the packing spacer 36 that allows the lower chamber 98 to be in fluid communication with the angled chamber section 108 through the two channels 96 even if the two channels 96 are not aligned with the angled chamber section 108 when assembled. The pairs of o-ring seals 38 seal the chambers from the exterior of the body 12 and from the passageway.

A closure and breakoff assembly is located at the top of the body 12. Above the ball 46 is a spring 48. Above the spring 48 is a spring washer 50 and a spring retaining ring 52. The spring retaining ring 52 snaps into a recessed ring in the body 12 as does the base retaining ring 42. The spring is compressed between the spring washer 50 and the ball 46. Fluid can flow through the spring 48, the spring retaining ring 52 and the spring washer 50.

Although a particular piston and spring assembly have been described, it will be understood that other piston and spring assemblies and other shapes of components may be provided, within the scope of the invention. Por example, the shape of the diaphragm washer 34 may be machined from the packing spacer itself or may be totally eliminated with an increase in diameter of the packing spacer 36 and the location of the recess 92 and the rim 102. The lower piston 24 may be flattened. The shape of the upper piston 20 may be altered. A single piston rather than two pistons 20 and 24 may be used. The diaphragm 22 may be eliminated and the piston sealed to the cylinder in a fluid tight manner.

To the right in Figures 1 to 4 is a manual override. The manual override includes a crank barrel 56 and a pin 54 extending horizontally over the upper piston 20. The pin 54 is offset from the horizontal axis of the crank barrel 56 as best seen in Figure 4. There is a slot 90 in the outer surface of the crank barrel 56 sized to fit a screwdriver or other tool to turn the crank barrel 56. The crank barrel 56 has o-rings 5B extending in recesses in the circumference of the crank barrel 56 to provide a fluid tight connection to the body 12. The crank barrel 56 is held in position in the body 12 by a crank retaining ring 60 (See Figure 4) . In operation, the valve assembly i0 is first in the closed position shown in Figure 1 with the ball 46 seated in the angled passageway 84 by the expansion force of the compressed spring 48 to prevent fluid flow through the passageway. The top of the piston rod 44 may be spaced downward from the ball 46 by a gap 87. The valve assembly 10 is connected to a source of fluid for example an oil tank at the inlet 64. The connection may be made with threads 78 or other means for example clamping. The body 12 has wrench flats 95 to facilitate the screw connection.

The inner adapter 16 is connected to a flow line by threads 99 and the outer connector is connected to an outer line by threads 72. When these connections are made, the passageway is fluid tight from the fluid supply to the fluid recipient device through the flow line. The chambers and the space between the outer line and the flow line also form a fluid tight chamber. The chambers 76, 107, 109, 80, 108, 96, 106 and 98 are pressurised with a gas. An example of how the chambers may be pressurised is described below with reference to Figures 6 to 10. The increase in pressure in the lower chamber 98 pushes the pistons 24 and 22 upward which in turn move the piston rod 44 upward. The piston rod 44 pushes the ball 46 upward, compressing the spring 43 and lifting the ball 4 S out of contact with the angled passageway 84 to open the passageway. The pistons 24 and 22 move upward with increased pressure until the shoulders 94 of the lower piston 24 contact the lower surface of the diaphragm washer 34 as shown in Figure 2. Figure 2 depicts the normal operation of the valve assembly 10 with the chamber charged with a surveillance fluid at a pressure and a fluid flowing through the passageway from the inlet 64 to the outlet 66.

The valve assembly 10 will move from the open position of Figure 2 to the closed position of Figure 1 in response to several modes of failure. The space between the flow line and the outer line provides surveillance of the line quality. The chamber, and by extension the volume between the flow line and the outer line, are pressurised to a higher fluid pressure than the pressure outside the outer line and the pressure within the flow line. If, for example, the outer line is ruptured or if the flow line corrodes, the pressure in the chamber 16 will decrease because fluid from the outer line will leak to the outside or to the flow line since they are at a lower pressure. Through the interconnection of the chambers the pressure in the lower chamber 98 will decrease. The expansion force of the spring 48, will push the ball 45 down againat the reduced pressure to close the valve assembly. Also, the valve assembly 10 operates as a breakaway valve- The neck 91 of the valve body 12 is relatively narrow compared to the rest of the body 12. If the valve assembly 10 is struck with a shearing force, the valve is predisposed to break at the neck 91. If the neck 91 is broken, chamber 80 will also be broken causing a pressure loss in the chamber 80. The interconnection of the chambers means that the pressure will be lost in the lower chamber 98 again closing the valve as described above. Even if the chamber 80 is absent from the body, a complete shearing of the neck 91 will cause the upper portion to separate from the main part of the body 12. This will result in the valve closing as a breakoff valve when contact is lost between the ball 46 and the rod 44, without a loss in fluid pressure in the chamber.

The manual override can be used to close the valve in the absence of failure. The manual override operates by inserting a screw drive in the slot 90 of the crank barrel 56 and turning the screw driver. The pin 54 extends into the piston cylinder 88 through an opening 89. Figure 5 depicts the path 93 of the pin 54. If the pin 54 is at the top of the opening 89, it does not contact the upper piston 20. When the crank barrel 56 is rotated, the pin 54 traces the downward angled path 93 to press the upper piston downward to the closed position shown in Figure 5. The compressible fluid in the chamber, i.e. gas, is compressed. Again a gap ia opened between the piston shaft 44 and the ball 46. The pin 54 sits in the channel 104 in the upper piston 20. Although a particular manual override system is described, other manual overrides with operate to move other components of the asaembly to remove the upward force from the ball 46 or increase the downward force on the ball 46 can we used. The manual override can be removed by reversing the rotation. Figures 6 to 10 depict embodiments of the invention which utilise two or more valves which act as the valve arrangement. In Figure 6 a valve assembly 110 comprises a body 112 having a passageway 114 defined therethrough from a first end or inlet 116 to a second end or outlet 118. Within the body 112 there is a breakaway valve 120 and a shut-off valve 122. The valve assembly 110 may also include a flow line or conduit 130. In operation both valves are in the open position. In Figure 6, the breakaway valve 120 is shown in the open position and the shut-off valve 122 is shown in the closed position. This is the position of the valves before they are installed. The shut -off valve 122 will only move to the open position when pressurised as discussed below.

The valve assembly HO is adapted to connect to a fluid source at the inlet 116 through the breakaway valve 120. Similarly, the valve assembly HO is adapted to connect to a fluid recipient device through the conduit 130 at the outlet iia.

In operation, a fluid flows from the inlet 116 through the passageway 114 and out the outlet 118. If the valve assembly 110 is broken at the breakaway valve 120, the breakaway valve 120 will close. The sealing portion of the breakaway valve 120 is maintained at the fluid source to stop fluid from leaking from the fluid source.

Similarly, if the conduit 130 is damaged, either by rupturing externally or internally, the shut-off valve 122 will close, again, preventing fluid from leaking from the fluid source .

In Figure S, the breakaway valve 120 is oriented in the direction of fluid flow through the passageway 114. The breakaway valve 120 normally has a circular cross section. Screw threads 126 are defined around the outer circumference of the breakaway valve 120 at the inlet end 116 to allow the valve assembly 110 to be screwed to a fluid source. A limiting Bhoulder 142 projects radially outward adjacent the inner end the screw threads 126 to limit the screw travel over the breakaway valve 120.

The breakaway valve 120 also has a machined relief point 203 machined around the entire circumference of the breakaway valve 120. The machined relief point 203 defines a predictable point of weakness such that the breaking of the breakaway valve 120 will be controlled and occur at the machined relief point 203.

A housing 146 of the breakaway valve 120 is inset into a housing 148 of the shut-off valve 122. The housing 146 of the breakaway valve 120 is fixed to the housing 148 of the shut-off valve 122 by screws 144. The passageway 114 is defined through the housing 146. Internal to the passageway 114 within the housing 145, there is, in order from the inlet 116, a retaining plate 150, a spring 204, a disk plate 201, a breakaway valve member 138, a disc plate 202, and a retaining plate 152. The retaining plane 152 and the disc plate 202 are held in the breakaway valve housing 146 by resting within notches cut out of the interior of the housing 146. An end of the breakaway valve member 138 rests against the disc plate 202. The disk plate 202 in turn rests against the opposite end of the breakaway valve member 138. The spring 204 in turn rests against the disk plate 201 and the retaining plate 150 holds the spring 204 in place.

Figure 6 shows rotated views of the disk place 201 and disk plate 202 such that it is clear that fluid flow occurs around these elements. Similarly, fluid also flows through retaining plate 152 and the retaining plate 150. The breakaway valve 120 is shown in Figure 6 in an open position. In a closed position, i.e. when the valve breaka at the relief point 203, the compressive force on the spring 204 exerted by a combination of the plate 152 acting against the disc plate 202, the member 138 and the disk plate 201 will be removed. The spring 204 will then expand pushing the disk plate 201 and the member 138 towards the right as shown in Figure 1. The conical surface of the member 138 will come to rest against the corresponding conical surface 140 of the housing 146 thereby closing off the passageway 114. Fluid flow from the inlet 116 also helps to close the breakaway valve 120.

Turning to the shut-off valve 122, the shut-off valve 122 is comprised of a housing 14Θ, an upper housing 146, a lower housing 154 and a right housing 158. These multiple housing components are depicted for manufacturability and are not essential elements in the invention. The various housings are connected by screws 160, 1S2 and 164. Seals 170 are depicted as black rectangles/circles throughout the Figures. These seals are intended to provide fluid tight connections. Other means of providing fluid tight connections may also be used.

As previously noted, the Figures show the shut -off valve 122 in a closed position. In an open position, a chamber 210 is pressurised to move a piston 214 downward against the piston rod 216 which in turn moves downward against the poppet 218. The poppet 218 has a shoulder which compresses the spring 220 and maintains the valve in an open position by opening the passageway 114 at an interface 124 between the housing 148 and the poppet 218- The shut-off valve 122 has a fluid inlet at

212, for example, a snifter valve, secured by screws 166, which allows the chamber 210 to be pressurised. The chamber is sealed. Once the chamber is pressured, it will maintain the gas pressure without the need for external actuation. Thus the system, once charged, requires no external force to remain active The portion of the chamber 210 which surrounds the piBton rod 216 is not pressurised. An outlet 149 is provided to maintain environmental pressure in the non-pressurised portion of chamber 210

It can be seen m Figure 6 that the chamber 210 is connected through a pilot line 222, which is internal to the housings 148 and 158, to a surveillance area 224. The conduit 130 ie comprised of an outer conduit 182 and an inner conduit 184. The surveillance area 224 extends between these conduits.

The outer conduit 182 can be armour coated, for example, with urethane. The conduit 182 may be comprised of malleable copper which can resist some trauma without failure.

At either end of the conduit 130 are flanges 180 and

188. The flange 180 is welded or otherwise sealed to the housing 158 and the outer conduit 182 to provide a fluid tight seal Similarly, the flange 188 is connected to the outer conduit 30 and an outlet connector 226. The outlet connector 226 has defined within it an opened fluid pressurising entrance 190. in use, this entrance would be covered by a pressurisation means comparable to that shown at 212.

In use, the chamber 210, the pilot line 222 and the surveillance area 224 will be pressurised with a fluid either at 212 or through 190. The fluid may be an inert gas for example nitrogen. The pressurisation can be done when the valve assembly 110 is installed. There ia no requirement to retain a gas supply in contact with the valve assembly 110 since the chamber defined by the chamber 210, the pilot line 222 and the surveillance area 224 is a closed system. The outlet connector 226 has external threads and a shoulder for attachment to the recipient device of bhe fluid delivery system.

In operation, the shut-off valve 122, as previously noted, is in an open position. The shut-off valve 122 would normally first be installed m a fluid delivery system and then opened by pressurising the chamber 210. If the conduit 130 is ruptured or otherwise compromised, for example by puncturing externally or by corrosion internally, from the fluid travelling through the inner conduit, fluid pressure in the surveillance area 224, the pilot line 222 and the chamber 210 is lost thereby allowing the spring 220 to expand and move the poppet 218 to close the passageway 114 at the interface 124. This will also happen if the conduit 130 is for some reason detached from the housing 158 since the surveillance process is internal to the system. The internal surveillance system also means that the system can be buried.

Figures 7 to 10 depict other embodiments of the invention- These embodiments are described only m respect of the differences from the embodiment of Figure 6.

The embodiment depicted in Figure 7 has an extra pilot line 222' which connects to a further surveillance area 224' . The pilotline 222' extends through the housing 148 and connects to the surveillance area 224' in the housing 146. The surveillance area 224' extends past the relief point 203. Fluid communication is thus provided between the breakaway valve and the shut-off valve. In operation, this means that the breaking of the breakaway valve 120 at the relief point 203, m addition to causing the breakaway valve to close, as described above, will also cause the shut-off valve 122 to close because of the loss of surveillance fluid pressure in the chamber 210 through the interconnected broken surveillance area 224' . The result is that a break at the relief point 203 causes both the breakaway valve 120 and the shut-off valve 122 to close. The breakaway valve 120 is retained on the inlet side of the break and the shut -off valve 122 is regained on the outlet aide of the break, closing both the inlet and the outlet .

The embodiment shown in Figure 8 is based on the embodiment shown in Figure 7 but has the addition of a second breakaway valve 120' at the outlet 118 of the conduit 130. The second breakaway valve 120' would normally be connected to a fluid recipient device in the same manner thac the breakaway valve 120 is connected to a source of fluid. The second breakaway valve 120' has a machined relief point 203' and the surveillance area 224' extends past the relief point 203'. In operation, the breaking of the breakaway valve 120' at the relief point 203' causes the breakaway valve 120' to close as described above with respect to breakaway valve 120. The shut- off valve 122 will also close because of the loss of surveillance fluid pressure in the chamber 210 through the interconnected broken surveillance area 224. Again, the result is that a break at the relief point 203' causes both the second break away valve 120' and the shut-off valve 122 to close. The breakaway valve 120' is retained on the outlet side of the break and the shut -off valve 122 is retained on the inlet aide of the break, closing both the inlet and the outlet.

Although the Figures have been described as having a particular inlet to outlet orientation, it will be understood that the opposite orientation is also possible. Additionally, multiple valve assemblies can be combined in a valve system. Figure 9 depicts Buch a system with two valve assemblies 110 combined with opposite orientation. Figure 10 depicts a system with three shut-off valves 122 in series, and a breakaway valve 120 at each end. The surveillance area in Figure 10 can be one continuous surveillance area or a number of separate surveillance areas between the valves. For separate surveillance areas, a charging valve would need to be provided for each area . With multiple surveillance areas, if a rupture occurs in a segment of conduit, only the values monitored by the surveillance area which was ruptured would close. With one surveillance area, if a rupture occurs in a segment of conduit, all the valves monitored by the surveillance area would close to prevent any possible back flow from the receiving device. Multiple valve assemblies according to the embodiment depicted in Figures 1 to 5 can be combined as depicted in Figures 9 and 10.

Multiple snifter valves can be provided to allow the surveillance fluid to be introduced to the syBtem at any location along the Bystem. Means other than shifter valves may be used to charge, i.e. introduce the fluid to the system.

The system requires no external elements to maintain the fluid pressure once charged. The system is contained within the valve body and the conduits.

A pressure gauge may be added to the surveillance area 224 to provide a visual cue as to the integrity of the surveillance fluid.

The size of the system can be scaled up or down with respect to the size of the conduit or piping.

Although a specific examples of valves are shown in the drawings, it would be appreciated by those skilled in the art that other forms of valves, including other closure mechanisms and breakaway mechanisms, can be used without deviating from the scope of the invention. The valves may be pneumatic. For example, the spring may be eliminated and the pressure of the fluid flowing in the passageway alone may be used to close the valve.

In the Figures, the orientation and relative positions of the breakaway member of the breakaway valve is perpendicular to the closure mechanism for the shut -off valve. Other orientations of the closure mechanisms are contemplated by the invention. The configuration shown in the Figures has the advantage of retaining a substantially horizontal fluid flow passage 114.

Although a breakaway mechanism and fluid surveillance system is shown in the Figures, it would be appreciated that other types of shut-off valves are contemplated within the scope of the invention.

Although the conduit ie shown in the drawings as having two concentric conduits with a space therebetween, it will be appreciated that the surveillance area 224 need not extend through the entire conduits. If other forms of safety valves are utilised it may be that no surveillance area 224 is provided.

The present invention may be used in various fluid delivery systems, for example, to connect an oil tank to a furnace or a gas tank to a motor. The single valve assembly and single conduit configuration of Figures 1 to B may be useful, for example in protecting the flow of fluid from a tank to a furnace. The dual valve syatem of Figure 7 is configured to allow flow to be terminated in both directions by the opposite orientation of the individual valve assemblies. Any back flow with any amount of head pressure acts on the shut-off valve at that end to help close the shut-off valve. The multiple valve and multiple conduit system of Figure 9 adds, beyond the system of Figure 1, the ability to shut off one or all valves should a failure occur anywhere along a flow line.

The size of the system can be scaled up or down with respect to the piEe of the conduit or piping.

The invention discloses a valve assembly adapted to protect against multiple modes of failure.

The embodiments described recited valve assemblies that closes as result of a decrease in fluid pressure. It will however be understood that the invention contemplates other valve assemblies which may be activated in other ways, for example by an increase in fluid pressure to open or close the valve .

Although a particular orientation of up/down and left/right are used to facilitate the description, it will be understood that this orientation is not required in operation.

The invention is intended to encompass all features disclosed herein as well as all combinations thereof.

It is to be understood that within the scope of the appended claims, the invention may be practised otherwise than as specifically described herein.

Claims

We claim:

1. A valve assembly comprising:

a body, a passageway defined through the body, the passageway having a first end and a second end;

a valve arrangement between the first end and the second end, the valve arrangement being movable between an open position in which the passageway is open and a closed position in which the passageway is closed;

wherein the valve arrangement is adapted to close the passageway in response to at least two modes of failure.

2. The valve assembly according to claim 1 wherein the valve arrangement comprises a single valve member.

3. The valve assembly according to claim 2 further comprising a stop means for holding the valve member in an open position.

4. The valve assembly according to claim 3 further comprising a biasing means biasing the valve member towards a closed position wherein the stop means is for holding the valve member in the open position against the biasing means.

5. The valve assembly according to any one of claims 1 to 4 wherein one of the at least two modes of failure is a change in fluid pressure.

6. The valve assembly according to any one of claims 1 to 5 wherein the valve further comprises a chamber adapted to contain a fluid at a fluid pressure and the valve member is adapted to close the passageway when the fluid pressure changes by at least a predetermined amount .

7. The valve assembly according to claim 6 wherein the chamber is connectable to a first conduit and the passageway is connectable to a second conduit adjacent the first conduit and the valve member is adapted to close the passageway when the first conduit is broken.

8. The valve assembly according tc claim 7 wherein a portion of the chamber encircles a portion of the passageway.

9. The valve assembly according to any one of claims 1 to 5 wherein the body further comprises a breakaway means and one of the at least two modes of failure comprises a fracture of the body at the breakaway means .

10. The valve assembly according to any one of claims 6 to 8 wherein the body further comprises a breakaway means and one of the at least two modes of failure comprises a fracture of the body at the breakaway means.

11. The valve assembly according to claim 10 wherein a portion of the chamber is positioned in the region of the breakaway means .

12. The valve assembly according to claim 3 or 4 further comprising a mechanical override for deactivating the stop means absent failure.

13. The valve assembly according to claim 12 wherein the mechanical override comprises a depression member moveable between an activated position and a deactivated position wherein, in the activated position, the depression member exerts a force on the scop member to remove a closing force from the valve member .

14. The valve assembly according to claim 13 wherein the stop means comprises a piston exerting a opening force on che valve member and the override comprises a depression member which moves the piston to a position where the opening force is removed, from the valve member.

15. The valve assembly according χ.o claim 14 wherein the depression member is moveable between the activated position and the deactivated position by rotation of a body of the mechanical override.

16. The valve assembly according to claim 14 or 15 wherein the piston and body define cooperating shoulders and protrusions which limit the travel of the piston in an opening direction.

17. A valve assembly comprising.-

a body;

a passageway defined through the body, the passageway having a firat end and a second end;

a valve member between the first end and the second end, the valve member being movable between an open position in which the passageway is open and a closed poeition in which the passageway ia closed;

a biasing means for biasing the valve member towards a closed position,

a stop means for holding the valve member in an open position against the biasing means; and

a sealable chamber maintainable at a fluid pressure without continuous external actuation;

wherein the valve member is adapted to close the passageway in response to a change in the fluid pressure.

18. The valve assembly according to claim 17 wherein the fluid is a gas .

19. The valve assembly according to claim 17 or 18 wherein the chamber consists of a body portion internal to the body and a conduit portion associated with a flow line connected to the passageway.

20. The valve assembly according to any one of claims 17 to 19 further comprising a mechanical override adapted to deactivate the stop means without the change in fluid pressure.

21. The valve assembly according to any one of claims 17 to 20 wherein the mechanical override comprises a depression member moveable between an activated position and a deactivated position wherein, in the activated position, the depression member exerts a force on the stop member to remove an opening force from the valve member.

22. The valve assembly according to claim 21 wherein the depression member is moveable between the activated position and the deactivated position by rotation of the mechanical override .

23. The valve assembly according to claim 19 wherein the valve member is adapted to close the passageway when the flow line is broken.

24. The valve assembly according to claim 23 wherein the conduit portion encircles the flow line.

25. A valve assembly comprising:

a body comprising a breakaway valve and a ahut-off valve;

a passageway defined through the body, wherein the passageway has a. first end and a second end; the breakaway valve connected between the first end and the second end wherein the breakaway valve as adapted to close the passageway when broken,- and

the shut-off valve being connected between the first end and the second end wherein the shut off-valve is adapted to activate in response to a change in fluid pressure.

26. The valve assembly according to claim 25 wherein the shut-off valve is adapted to activate when the breakaway valve is broken.

27. The valve assembly according to claim 26 wherein the breakaway valve is in fluid communication with the shut-off valve.

28. The valve assembly according to claim 27 wherein the breakaway valve reduces the fluid pressure when broken.

29, The valve assembly according to any one of claims 25 to 28 wherein the breakaway valve is located between the first end and the shut-off valve.

30. The valve assembly according to any one of claims 25 to 29 further comprising a conduit portion connected to the passageway and the shut-off valve is adapted to activate when the fluid pressure decreases in the conduit portion.

31. The valve assembly according to claim 30 wherein the conduit portion has an outer conduit and an inner conduit and the shut-off valve is adapted to activate when at least one of the outer conduit and the inner conduit is broken.

32. The valve assembly according to claim 31 wherein a sealed chamber extends between the inner conduit and the outer conduit, the sealed chamber containing a fluid at the fluid pressure, the fluid pressure within the chamber controlling the shut-off valve.

33. The valve assembly according to any one of claims 26 to 28 further comprising a second breakaway valve spaced apart along the conduit wherein the second breakaway valve is adapted to close the conduit when broken.

34. The valve assembly according to claim 33 wherein at lease one of the breakaway valve and the second breakaway valve is adapted to open the sealed chamber when broken.

35. The valve asseπibly according to any one of claims 25 to 34 wherein the shut-off valve is adapted to close the passageway in response to a decrease in fluid pressure.

36. A fluid valve system comprising two valve assemblies according to claim 1 connected in series in fluid communication.

37. A fluid valve system comprising two valve assemblies according to claim 32 connected in series by the conduit.

38. The fluid valve system according to claim 37 further comprising at least one shut-off valve connected in series between the at leaBt two valve assembles.

39. The fluid valve system according to claim 37 wherein a single chamber is defined.

40. The fluid valve system according to claim 37 wherein multiple chambers are defined.

41. A valve assembly comprising at least two valves connected in series by a conduit portion wherein the valves are adapted to activate in response to a change in fluid pressure in the conduit portion.

42. The valve assembly according to claim 41 wherein the conduit portion has an outer conduit and an inner conduit and the shut-off valve is adapted to activate when at least one of the outer conduit and the inner conduit is compromised.

43. The valve assembly according to claim 32 wherein a sealed chamber extends between the inner conduit and the outer conduit, the sealed chamber containing a fluid at the fluid pressure, the fluid pressure wirhin the chamber controlling the shut-off valves.