WO2024197819A1

WO2024197819A1 - Pressure relief valve for cryogenic fuel tanks

Info

Publication number: WO2024197819A1
Application number: PCT/CN2023/085492
Authority: WO
Inventors: Guangbin Cao; Mark Kendrick HAMM
Original assignee: Engineered Controls International LLC
Current assignee: Engineered Controls International LLC
Priority date: 2023-03-31
Filing date: 2023-03-31
Publication date: 2024-10-03
Anticipated expiration: 2025-09-30

Abstract

A pressure relief valve (100) for a cryogenic fuel tank, the pressure relief valve includes a valve body (200) that includes a valve seat (240), defines an inlet (210) and an outlet (220), and at least partially defines a chamber (230). The pressure relief valve includes a poppet (800) that is at least partially housed in the chamber and is configured to slide between a closed position and an open position. The poppet includes a poppet body (820) and a seat disc (870) coupled to the poppet body. The poppet body defines a bleed hole (860) that fluidly connects the chamber to the outlet such that a chamber pressure in the chamber is to equalize with an outlet-side pressure over time when the poppet is in the closed position or the open position. The pressure relief valve includes a spring (700) at least partially housed in the chamber and configured to bias the poppet toward the closed position.

Description

PRESSURE RELIEF VALVE FOR CRYOGENIC FUEL TANKS

TECHNICAL FIELD

This disclosure generally relates to pressure relief valves and, more particularly, to pressure relief valves for cryogenic fuel tanks.

BACKGROUND

Cryogenic fluids are fluids that are stored at cryogenic temperatures. For instance, liquid hydrogen is stored at temperatures of about -253 degrees Celsius (-423 degrees Fahrenheit) . Recently, cryogenic liquids, such as liquid hydrogen (LH2) , have been used as a fuel source. Such cryogenic liquids are typically stored in storage tanks and are dispensed from the storage tanks, for example, via a nozzle and a receptacle. For instance, cryogenic liquid may be dispensed from the storage tank and into a vehicle tank via a nozzle and a receptacle. The vehicle tank may be hard piped to an engine or fuel cell for use of the cryogenic liquid as fuel.

Over time, cryogenic liquid stored in a tank (e.g., a vehicle tank) may warm up (e.g., due to ambient temperatures) . In turn, some of the cryogenic liquid may boil into gaseous form, which causes the pressure within the tank to increase. Any increase of pressure within the tank may make it difficult to dispense the cryogenic fluid from the tank in a controlled manner. Thus, there is a need for an appropriate level of pressure to be maintained in the tank to enable the subsequent supply of cryogenic fluid in a controlled manner.

SUMMARY

An example pressure relief valve for a cryogenic fuel tank is disclosed herein. The pressure relief valve includes a valve body that includes a valve seat, defines an inlet and an outlet, and at least partially defines a chamber. The pressure relief valve includes a poppet at least partially housed in the chamber and configured to slide between a closed position and an open position. The poppet includes a poppet body and a seat disc coupled to the poppet body. The seat disc is configured to engage the valve seat in the closed position to fluidly disconnect the outlet from the inlet. The seat disc is configured to be disengaged from the valve seat in the open position to fluidly connect the outlet to the inlet. The poppet body defines a bleed hole that fluidly connects the chamber to the outlet in both the closed position and the open position such that a chamber pressure of cryogenic fluid in the chamber is to equalize with an outlet-side pressure of the cryogenic fluid over time when the poppet is in the closed position or the open position. The pressure relief valve includes a spring at least partially housed in the chamber and configured to bias the poppet toward the closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example pressure relief valve in accordance with the teachings herein.

FIG. 2 is an exploded view of the pressure relief valve of FIG. 1.

FIG. 3 is a cross-sectional view of the pressure relief valve of FIG. 1 in a closed position.

FIG. 4 is a cross-sectional view depicting forces acting on a poppet of the pressure relief valve of FIG. 1 to position the pressure relief valve in the closed position of FIG. 3.

FIG. 5 is a cross-sectional view of the pressure relief valve of FIG. 1 in a partially-open position.

FIG. 6 is a cross-sectional view depicting forces acting on the poppet of FIG. 4 to position the pressure relief valve of FIG. 1 in the partially-open position of FIG. 5.

FIG. 7 is a cross-sectional view of the pressure relief valve of FIG. 1 in a fully-open position.

FIG. 8 is a cross-sectional view depicting forces acting on the poppet of FIG. 4 to position the pressure relief valve of FIG. 1 in the fully-open position of FIG. 7.

DETAILED DESCRIPTION OF THE DRAWINGS

The description that follows describes, illustrates and exemplifies one or more embodiments of the present invention in accordance with its principles. This description is not provided to limit the invention to the embodiments described herein, but rather to explain and teach the principles of the invention in order to enable one of ordinary skill in the art to understand these principles and, with that understanding, be able to apply them to practice not only the embodiments described herein, but also other embodiments that may come to mind in accordance with these principles. The present specification is intended to be taken as a whole and interpreted in accordance with the principles of the present invention as taught herein and understood by one of ordinary skill in the art.

The scope of the present invention is intended to cover all such embodiments that may fall within the scope of the appended claims, either literally or under the doctrine of equivalents. The specification describes exemplary embodiments which are not intended to limit the claims or the claimed inventions. Features described in the specification, but not recited in the claims, are not intended to limit the claims.

It should be noted that in the description and drawings, like or substantially similar elements may be labeled with the same reference numerals. However, sometimes these elements may be labeled with differing numbers, such as, for example, in cases where such labeling facilitates a more clear description. Additionally, the drawings set forth herein are not necessarily drawn to scale, and in some instances proportions may have been exaggerated to more clearly depict certain features. Such labeling and drawing practices do not necessarily implicate an underlying substantive purpose.

Some features may be described using relative terms such as top, bottom, vertical, rightward, leftward, etc. It should be appreciated that such relative terms are only for reference with respect to the appended drawings. These relative terms are not meant to limit the disclosed embodiments.

An example pressure relief valve disclosed herein is configured to relieve backpressure created during operation of a cryogenic tank. The pressure relief valve (also referred to as “boil-off valve” ) is fluidly connected to and positioned between a mixing device and the gaseous portion of the cryogenic fluid, such as liquid hydrogen, stored within the tank. The pressure relief valve includes an inlet that is fluidly connected to the tank and an outlet that is fluidly connected to the mixing device, such that the pressure relief valve is downstream of the tank and upstream of mixing device. The pressure relief valve includes a poppet that is configured to open the pressure relief valve at a predefined pressure to fill pipe and/or tubing extending between its outlet and the mixing device. The mixing device includes a small orifice that feeds the excess gas of the liquid hydrogen received from the pressure relief valve. The excess gas mixes with oxygen and/or another catalyst to make water as a discharged product.

Backpressure may be created when the pressure relief valve is open and the pipe and/or tubing is filled with the excess gas. With other pressure relief valves, such backpressure may prevent the poppet from reclosing and/or result in chattering, for instance, by maintaining opening forces on the poppet. The poppet of the example pressure relief valve disclosed herein defines a bleed hole that fluidly connects a chamber of the pressure relief valve to the outlet of the pressure relief valve in both the closed position and the open position. In turn, a pressure of the cryogenic fluid in the pressure chamber is to equalize with an outlet-side pressure over time when the poppet is in the closed position or the open position. The pressure equalization between the pressure chamber and the outlet enables the poppet to close (e.g., slowly and/or in a delayed manner) in instances when backpressure may prevent other poppets from closing.

Turning to the figures, FIGS. 1-2 illustrate an example of pressure relief valve 100 in accordance with the teachings herein. As most clearly shown in FIG. 2, pressure relief valve 100 includes valve body 200, spring 700, and poppet 800. Pressure relief valve 100 of illustrated example also includes guide 300; one or more seals 400, 450; cap 500; and insert 600.

FIGS. 3-8 are a cross-sectional views of pressure relief valve 100 and poppet 800 of pressure relief valve 100. In particular, FIG. 3 depicts pressure relief valve 100 when poppet 800 is in a closed position, and FIG. 4 depicts forces acting on poppet 800 in the closed position. FIG. 5 depicts pressure relief valve 100 when poppet 800 is in a partially-open position, and FIG. 6 depicts forces acting on poppet 800 in the partially-open position. FIG. 7 depicts pressure relief valve 100 when poppet 800 is in an open position, and FIG. 8 depicts forces acting on poppet 800 in the open position.

Turning to FIG. 3, valve body 200 defines inlet 210 (also referred to as “inlet port” ) and outlet 220 (also referred to as “outlet port” ) . In the illustrated example, valve body 200 also defines inlet chamber 215 adjacent inlet 210 and outlet chamber 225 adjacent outlet 220. Flow path 205 of pressure relief valve 100 is defined by valve body 200 and extends between inlet 210 and outlet 220. When poppet 800 is in the closed position to fluidly disconnect outlet 220 from inlet 210, as depicted in FIG. 3, cryogenic fluid is prevented from flowing through flow path 205. Poppet 800 is configured to slide between the closed position and the open position. When poppet 800 is in the open position (FIG. 7) or a partially-open position (FIG. 5) , outlet 220 is fluidly connected to inlet 210 such that the cryogenic fluid is permitted to flow through flow path 205 from inlet 210 to outlet 220.

Valve body 200 at least partially forms a chamber 230 (also referred to as a “poppet chamber” or a “main chamber” ) . In the illustrated example, valve body 200 and cap 500 combine to define chamber 230. In other examples, valve body 200 may form chamber 230 without cap 500. Returning to the illustrated example, chamber 230 includes an enclosed end and an open end through which poppet 800 slidably extends. Cap 500 is configured to couple to valve body 200 to define chamber 230 with valve body 200. In the illustrated example, cap 500 is securely and sealingly coupled to valve body 200, at an end of valve body 200 opposite inlet 210, to define the enclosed end of chamber 230. Cap 500 includes threads 510 that threadably couple to inner surface 235 of valve body 200 to form the sealed connection.

Spring 700 is at least partially housed in chamber 230 with poppet 800 and is configured to bias poppet 800 toward the closed position. In the illustrated example, a first end of spring 700 engages poppet 800 to bias poppet 800 toward the closed position. For example, the first end of spring 700 engages spring seat 836 of poppet 800. Additionally, an opposing second end of spring 700 engages a spring seat 610 of insert 600. Insert 600 is securely positioned within chamber 230 to enable spring 700 to bias poppet 800 toward the closed position. In the illustrated example, insert 600 is coupled to inner surface 235 of valve body 200 via threads 620 to enable insert 600 to be adjustably positioned within chamber 230 A biasing force of spring 700 is adjustable by adjust the position of insert 600. That is, spring 700 is configured to extend between and engage insert 600 and poppet 800 such that adjustment of the position of insert 600 adjusts the biasing force of spring 700. Insert 630 also includes opening to enable fluid to flow through insert 630 and to the enclosed end of chamber 230.

Poppet 800 slidably extends through chamber 230 and part of flow path 205 of valve body 200. In the illustrated example, poppet 800, which includes poppet body 820 and seat disc 870, is configured to slide along a longitudinal axis that extends through a center point of inlet 210 and along a center axis of chamber 230. Guide 300 is configured to guide poppet 800 in axial movement between the closed position and the opening position. Guide 300 is positioned radially between valve body 200 and poppet 800 in chamber 230 toward the open end of chamber 230. Guide 300 is secured in place against inner surface 235 of valve body 200, for example, via press fit.

Pressure relief valve 100 also includes one or more seals 400, 450 that are configured to prevent fluid from around an exterior surface of poppet 800 into and out of chamber 230. For example, seals 400, 450 are positioned toward the open end of chamber 230 to slidably and sealingly engage an outer surface of poppet 800 to prevent fluid from flowing around poppet 800. Seal 400 is configured to engage and form a sealed connection between valve body 200 and poppet 800. In the illustrated example, seal 400 is a spring-loaded that is positioned radially between and sealingly engages inner surface 235 of valve body 200 and the outer surface of poppet 800. Seal 400 is axially positioned between an end of guide 300 and ledge 250 of valve body 200 that is adjacent the open end of chamber 230. Seal 450 is configured to engage and form a sealed connection between guide 300 and poppet 800. Seal 450 (e.g., an O-ring) is positioned farther into chamber 230 and is configured to further seal the exterior of poppet 800. In the illustrated example, the seal 450 is positioned within groove 310 of guide 300 and is configured to extend radially between and sealingly engage guide 300 and the outer surface of poppet 800.

Turning to FIGS. 4, poppet 800 includes opposing inner end 810 and outer end 815. Inner end 810 is to remain in chamber 230 during operation of pressure relief valve 100, and outer end 815 is to extend out of chamber 230 during operation. Poppet body 820 of poppet 800 extends from inner end 810 toward outer end 815, and seat disc 870 of poppet 800 is coupled to poppet body 820 at outer end 815. Poppet body 820 includes first segment 830, second segment 840, and intermediate segment 850. First segment 830 is adjacent inner end 810, second segment 840 is adjacent outer end 815, and intermediate segment is between first segment 830 and second segment 840.

First segment 830 of poppet body 820 is a wall that defines cavity 832 and an opening to cavity 832 at inner end 810. Poppet body 820 defines spring seat 836 that spring 700 engages to bias poppet 800 toward the closed position. For example, spring 700 is configured to extend through the opening at inner end 810, into cavity 832, and engage spring seat 836. Poppet body 820 also defines bleed hole 860 that fluidly connects chamber 230 to outlet chamber 225 when poppet 800 is in the closed position. As disclosed below in greater detail, bleed hole 860 is configured such that chamber 230 remains fluidly connected to outlet 220 when poppet 800 is in the closed position, the open position, and the partially open positions therebetween. In turn, a chamber pressure of cryogenic fluid in chamber 230 equalizes with an outlet-side pressure of the cryogenic fluid over time during operation of pressure relief valve 100 (e.g., when poppet 800 is in the closed position or the open position) . That is, bleed hole 860 is configured to enable the chamber pressure in chamber 230 to increase after the outlet-side pressure has increased slowly and decrease after the outlet-side pressure has decreased.

In the illustrated example, intermediate segment 850 of poppet body 820 defines bleed hole 860. In other examples, another portion of poppet body 820, such as first segment 830 or second segment 840, may define bleed hole 860. Additionally, second segment 840 defines recess 845 at outer end 815 that is configured to securely receive seat disc 870. As disclosed below in greater detail, first segment 830 defines outer diameter 834 of poppet body 820. First segment 830 has an outer diameter that is greater than that of second segment 840, and intermediate segment 850 has a truncated conical outer surface with an outer diameter that transitions between that of first segment 830 and that of second segment 840.

In the illustrated example, seat disc 870 is securely coupled to poppet body 820 at outer end 815. For example, seat disc 870 is securely received by recess 845 at outer end 815 of poppet 800. In other examples, seat disc 870 is integrally formed with poppet body 820. Seat disc 870 is configured to sealingly engage valve seat 240 in the closed position (FIG. 3) to fluidly disconnect inlet 210 and outlet 220, and seat disc 870 is configured to be disengaged from valve seat 240 in the partially open (FIG. 5) and open (FIG. 7) positions to fluidly connect outlet 220 to inlet 210. Seat disc 870 also includes contact surface 875 that is configured to contact valve seat 240 in the closed position. As disclosed below in greater detail, contact surface 875 of seat disc 870 has outer diameter 880. Outer diameter 880 (also referred to as “first outer diameter” ) of contact surface 875 of seat disc 870 is less than outer diameter 834 (also referred to as “second outer diameter” ) of poppet body 820.

As illustrated in FIGS. 4, 6, and 8, the positioning and movement of poppet 800 is controlled based a plurality of forces that act on poppet 800. That is, poppet 800 is configured to be positioned between the open position and the closed position based on a difference between an opening force and a closing force acting on poppet 800.

The opening force, F_O, corresponds with an inlet-side pressure of cryogenic fluid. More specifically, the opening force, F_O, equals the inlet-side pressure of the cryogenic fluid multiplied by the area of poppet 800 upon which the inlet-side pressure applies a force. As disclosed below in greater detail, that area is defined by outer diameter 880 of contact surface 875 of seat disc 870 in the closed position (FIG. 3) and is defined by outer diameter 834 of poppet body 820 in the partially-open position (FIG. 5) and the open position (FIG. 7) . That is, the opening force, F_O, equals the inlet-side pressure of the cryogenic fluid located at inlet 210 multiplied by the area defined by outer diameter 880 (e.g., in the closed position) or outer diameter 834 (e.g., in the partially-open and open positions) .

The closing force equals the sum of a biasing force, F_SP, of spring 700 and a chamber-pressure force, F_CP, that corresponds with a chamber pressure of the cryogenic fluid in chamber 230. The chamber-pressure force, F_CP, equals the chamber pressure of the cryogenic fluid located in chamber 230 multiplied by the area defined by outer diameter 834 of poppet body 820. That is, the chamber-pressure force, F_CP, is based on the chamber pressure and outer diameter 834 of poppet body 820. The biasing force, F_SP, of spring 700 may change as spring 700 expands and retracts as poppet 800 transitions between the open position and the closed position, for example, in accordance with to Hooke’s law.

When the opening force is greater than the closing force, poppet 800 is configured to move toward or remain positioned in the open position. That is, poppet 800 is configured to move toward or remain positioned in the open position when F_O > F_SP + F_CP. In other words, poppet 800 moves toward or remains in the open position when F_O -F_CP > F_SP. In contrast, when the closing force is greater than the opening force, poppet 800 is configured to move toward or remain positioned in the closed position. That is, poppet 800 is configured to move toward or remain positioned in the open position when F_O < F_SP + F_CP. In other words, poppet 800 moves toward or remains in the closed position when F_O -F_CP < F_SP.

Turning to FIG. 3, poppet 800 is in the closed position. In the illustrated example, the combination of the chamber-pressure force, F_CP, and the biasing force, F_SP, is greater than the opening force, F_O. In the closed position, the opening force, F_O, equals the inlet-side pressure at inlet 210 multiplied by the area defined by outer diameter 880 of contact surface 875 (FIG. 4) of seat disc 870 that is sealingly engaged with valve seat 240. That is, in the closed position, the opening force, F_O, is based on the inlet-side pressure and outer diameter 880. Outlet-side pressure at outlet 220 is null when poppet 800 is closed. By being fluidly connected to outlet 220 via bleed hole 860 of poppet 800, the chamber pressure of chamber 230 decreases over time to equalize with the outlet-side pressure as poppet 800 remains closed. For example, the chamber pressure of chamber 230 may approach equaling null when poppet 800 remains closed for an extended period of time. Poppet 800 is to open when the difference between the opening force, F_O, and the chamber-pressure force, F_CP, exceeds the biasing force, F_SP. For example, the threshold pressure difference (e.g., 200 psi) is reached when the inlet-side pressure at inlet 210 is at least at a predetermined threshold pressure (e.g., 200 psi) and the chamber pressure in chamber 230 is null (e.g., 0 psi) . That is, when poppet 800 is in the closed position, poppet 800 is configured to transition toward the open position when the chamber-pressure force, F_CP, is null and the opening force, F_O, is greater than the biasing force, F_SP, of spring 700.

FIG. 5 depicts poppet 800 in the partially-open position after poppet 800 has opened from the closed position. Once seat disc 870 of poppet 800 has disengaged from valve seat 240, outlet 220 becomes fluidly connected with inlet 210 such that the outlet-side pressure equals the inlet-side pressure (e.g., about 200 psi) . That is, the outlet-side pressure equals the inlet-side pressure when poppet 800 is in the partially-open position or the open position. Bleed hole 860 of poppet 800 also causes the chamber pressure of chamber 230 to increase slowly over time toward the new increased outlet-side pressure at outlet 220. Bleed hole 860 has a relatively small size (e.g., a diameter of about 0.028 inches) to cause the pressure chamber in chamber 230 to slowly equalize with the outlet-side pressure of the cryogenic fluid at outlet 220.

Additionally, poppet 800 is shaped such that the opening force, F_O, increases when poppet 800 opens. For example, in the closed position, the opening force, F_O, equals the inlet-side pressure at inlet 210 multiplied by the area defined by outer diameter 880 of contact surface 875 of seat disc 870. When poppet 800 opens, the inlet-side pressure is applied to a greater area of poppet 800. In particular, the area is initially defined by outer diameter 880 when poppet 800 is closed and is then defined by outer diameter 834 of poppet body 830 when poppet 800 opens. That is, in the open position, the opening force, F_O, is based on the inlet-side pressure and outer diameter 834. The opening force, F_O, increases since outer diameter 880 is greater than outer diameter 834 and the inlet-side pressure remains unchanged when poppet 800 opens.

As a result, poppet 800 is configured to have a hysteresis thresholding function to prevent poppet 800 from chattering between the open and closed positions when a constant inlet-side pressure is present. Poppet 800 is configured to open when the opening force exceeds a lower threshold force (also referred to as a “lower hysteresis force” ) , and poppet 800 is configured to close only when the closing force exceeds an upper threshold force (also referred to as an “upper hysteresis force” ) . The lower hysteresis force corresponds the area defined by outer diameter 880 of contact surface 875 of seat disc 870, and the upper hysteresis force corresponds with the area defined by outer diameter 834 of poppet body 830. That is, outer diameter 880 of contact surface 875 of seat disc 870 defines a lower hysteresis threshold for opening poppet 880, and outer diameter 834 of poppet body 830 defines an upper hysteresis threshold for closing poppet 800. In turn, poppet 800 remains open for a period of time while the chamber-pressure force, F_CP, increases to overcome the upper hysteresis force, instead of immediately closing once the chamber-pressure force, F_CP, increases by a marginal amount that would otherwise quickly overcome the lower hysteresis force.

FIG. 7 depicts poppet 800 in the open position (also referred to as the “fully open position” ) after poppet 800 has continued to open from the partially-open position of FIG. 5. Outlet 220 remains fluidly connected with inlet 210 such that the outlet-side pressure remains equal to the inlet-side pressure (e.g., about 200 psi) . The opening force, F_O, remains equal to the inlet-side pressure at inlet 210 multiplied by the area defined by outer diameter 834 of poppet body 830.

Bleed hole 860 of poppet 800 continues to enable the chamber pressure of chamber 230 to increase over time toward the increased outlet-side pressure at outlet 220. Again, bleed hole 860 has a relatively small size (e.g., a diameter of about 0.028 inches) to cause the pressure chamber in chamber 230 to slowly equalize with the outlet-side pressure of the cryogenic fluid at outlet 220. In turn, bleed hole 860 is sized to further prevent chatter of poppet 800 between the open and closed positions.

For example, poppet 800 begins to transition back toward the closed position once the pressure chamber in chamber 230 increases to a pressure that results in the chamber-pressure force, F_CP, overcoming the upper hysteresis force associated with poppet 800. That is, when poppet 800 is in the open position, poppet 800 is configured to transition toward the closed position when the chamber-pressure force, F_CP, reaches the upper hysteresis force threshold that corresponds with the closing force being greater than the opening force. Bleed hole 860 has a relatively small diameter, which causes the pressure chamber in chamber 230 to increase slowly over time. In turn, poppet 800 closes slowly while the pressure chamber in chamber 230 slowly equalizes with the outlet-side pressure of outlet 220.

Once poppet 800 returns to the closed position, the outlet-side pressure at outlet 220 is to decrease back to null. Bleed hole 860 enables the pressure chamber in chamber 230 to slowly decrease over time. Once the pressure chamber in chamber 230 decreases to a pressure (e.g., null) that corresponds with the lower hysteresis threshold, poppet 800 reopens.

An example pressure relief valve for a cryogenic fuel tank includes a valve body that includes a valve seat, defines an inlet and an outlet, and at least partially defines a poppet chamber. The pressure relief valve includes a poppet at least partially housed in the poppet chamber and configured to slide between a closed position and an open position. The poppet includes a poppet body and a seat disc coupled to the poppet body. The seat disc is configured to engage the valve seat in the closed position to fluidly disconnect the outlet from the inlet. The seat disc is configured to be disengaged from the valve seat in the open position to fluidly connect the outlet to the inlet. The poppet body defines a bleed hole that fluidly connects the poppet chamber to the outlet in both the closed position and the open position such that a chamber pressure of cryogenic fluid in the poppet chamber is to equalize with an outlet-side pressure of the cryogenic fluid over time when the poppet is in the closed position or the open position. The pressure relief valve includes a spring at least partially housed in the poppet chamber and configured to bias the poppet toward the closed position.

Some examples further include a cap that is configured to couple to the valve body to define the poppet chamber with the valve body.

Some examples further include an insert that is configured to couple to the valve body and be adjustably positioned within the poppet chamber via threads. The spring is configured to extend between and engage the insert and the poppet such that adjustment of a position of the insert adjusts a biasing force of the spring.

In some examples, the seat disc is securely coupled to the poppet body.

Some examples further include a guide configured to be positioned radially between the valve body and the poppet in the poppet chamber. The guide is configured to guide axial movement of the poppet between the closed position and the open position.

Some examples further include a seal that is configured to engage and form a sealed connection between the valve body and the poppet. Further, in some such examples, the poppet body defines the bleed hole to be located toward the seat disc such that the bleed hole is unable to retract beyond the seal as the poppet transitions to the open position.

In some examples, the poppet is configured to be positioned between the open position and the closed position based on a difference between an opening force and a closing force acting on the poppet. The opening force corresponds with an inlet-side pressure of the cryogenic fluid. The closing force equals a combination of a biasing force of the spring and a chamber-pressure force that corresponds with a chamber pressure of the cryogenic fluid in the poppet chamber. In some such examples, when the poppet is in the closed position, the poppet is configured to transition toward the open position when the chamber-pressure force is null and the opening force is greater than the biasing force of the spring. In some such examples, when the poppet is in the open position, the poppet is configured to transition toward the closed position when the chamber-pressure force reaches a predetermined force threshold that corresponds with the closing force being greater than the opening force. In some such examples, the chamber- pressure force is based on the chamber pressure of the cryogenic fluid and an outer diameter of the poppet body. In some such examples, the seat disc includes a contact surface that is configured to contact the valve seat in the closed position. The contact surface of the seat disc has a first outer diameter that is less than a second outer diameter of the poppet body. Further, in some such examples, the opening force is based on the inlet-side pressure and the first outer diameter in the closed position. The opening force is based on the inlet-side pressure and the second outer diameter in the open position such that the opening force is to increase as the poppet transitions from the closed position to the open position. Additionally, in some such examples, the first outer diameter of the seat disc defines a lower hysteresis threshold for opening the poppet and the second outer diameter of the poppet body defines an upper hysteresis threshold for closing the poppet.

In some examples, the outlet-side pressure is configured to equal an inlet-side pressure when the poppet is in the open position, the outlet-side pressure is to decrease when the poppet is in the closed position, and the bleed hole is configured to enable the chamber pressure to increase after the outlet-side pressure has increased and decrease after the outlet-side pressure has decreased.

Another examples pressure relief valve for a cryogenic fuel tank includes a valve body that includes a valve seat, defines an inlet and an outlet, and at least partially defines a poppet chamber. The pressure relief valve includes a poppet at least partially housed in the poppet chamber and configured to slide between a closed position and an open position. The poppet includes a seat disc that includes a contact surface having a first outer diameter. The contact surface is configured to engage the valve seat in the closed position to fluidly disconnect the outlet from the inlet and be disengaged from the valve seat in the open position to fluidly connect the outlet to the inlet. The poppet includes a poppet body having a second outer diameter that is greater than the first outer diameter. The poppet body defines a bleed hole that fluidly connects the poppet chamber to the outlet in both the closed position and the open position such that a chamber pressure of cryogenic fluid in the poppet chamber is to equalize with an outlet-side pressure of the cryogenic fluid over time when the poppet is in the closed position or the open position. The pressure relief valve includes a spring at least partially housed in the poppet chamber and configured to bias the poppet toward the closed position. The poppet is configured to be positioned between the open position and the closed position based on a difference between an opening force and a closing force acting on the poppet with the first outer diameter defining a lower hysteresis threshold for opening the poppet and the second outer diameter defining an upper hysteresis threshold for closing the poppet. In the closed position, the opening force is based on an inlet-side pressure and the first outer diameter of the contact surface of the seat disc. In the open position, the opening force is based on the inlet-side pressure and the second outer diameter of the poppet body such that the opening force is to increase as the poppet transitions from the closed position to the open position. The closing force equals a combination of a biasing force of the spring and a chamber-pressure force that corresponds with a chamber pressure of the cryogenic fluid in the poppet chamber and the second outer diameter of the poppet body.

Claims

A pressure relief valve for a cryogenic fuel tank, the pressure relief valve comprising:

a valve body including a valve seat, defining an inlet and an outlet, and at least partially defining a poppet chamber;

a poppet at least partially housed in the poppet chamber and configured to slide between a closed position and an open position, wherein the poppet includes a poppet body and a seat disc coupled to the poppet body, wherein the seat disc is configured to engage the valve seat in the closed position to fluidly disconnect the outlet from the inlet, wherein the seat disc is configured to be disengaged from the valve seat in the open position to fluidly connect the outlet to the inlet, and wherein the poppet body defines a bleed hole that fluidly connects the poppet chamber to the outlet in both the closed position and the open position such that a chamber pressure of cryogenic fluid in the poppet chamber is to equalize with an outlet-side pressure of the cryogenic fluid over time when the poppet is in the closed position or the open position; and

a spring at least partially housed in the poppet chamber and configured to bias the poppet toward the closed position.
The pressure relief valve of claim 1, further comprising a cap that is configured to couple to the valve body to define the poppet chamber with the valve body.
The pressure relief valve of claim 1, further comprising an insert that is configured to couple to the valve body and be adjustably positioned within the poppet chamber via threads, wherein the spring is configured to extend between and engage the insert and the poppet such that adjustment of a position of the insert adjusts a biasing force of the spring.
The pressure relief valve of claim 1, further comprising a guide configured to be positioned radially between the valve body and the poppet in the poppet chamber, wherein the guide is configured to guide axial movement of the poppet between the closed position and the open position.
The pressure relief valve of claim 1, further comprising a seal that is configured to engage and form a sealed connection between the valve body and the poppet.
The pressure relief valve of claim 5, wherein the poppet body defines the bleed hole to be located toward the seat disc such that the bleed hole is unable to retract beyond the seal as the poppet transitions to the open position.
The pressure relief valve of claim 1, wherein the poppet is configured to be positioned between the open position and the closed position based on a difference between an opening force and a closing force acting on the poppet, wherein the opening force corresponds with an inlet-side pressure of the cryogenic fluid, wherein the closing force equals a combination of a biasing force of the spring and a chamber-pressure force that corresponds with a chamber pressure of the cryogenic fluid in the poppet chamber.
The pressure relief valve of claim 7, wherein, when the poppet is in the closed position, the poppet is configured to transition toward the open position when the chamber-pressure force is null and the opening force is greater than the biasing force of the spring.
The pressure relief valve of claim 7, wherein, when the poppet is in the open position, the poppet is configured to transition toward the closed position when the chamber-pressure force reaches a predetermined force threshold that corresponds with the closing force being greater than the opening force.
The pressure relief valve of claim 7, wherein the chamber-pressure force is based on the chamber pressure of the cryogenic fluid and an outer diameter of the poppet body.
The pressure relief valve of claim 7, wherein the seat disc includes a contact surface that is configured to contact the valve seat in the closed position, wherein the contact surface of the seat disc has a first outer diameter that is less than a second outer diameter of the poppet body.
The pressure relief valve of claim 11, wherein the opening force is based on the inlet-side pressure and the first outer diameter in the closed position, and wherein the opening force is based on the inlet-side pressure and the second outer diameter in the open position such that the opening force is to increase as the poppet transitions from the closed position to the open position.
The pressure relief valve of claim 12, wherein the first outer diameter of the seat disc defines a lower hysteresis threshold for opening the poppet and the second outer diameter of the poppet body defines an upper hysteresis threshold for closing the poppet.
The pressure relief valve of claim 1, wherein the outlet-side pressure is configured to equal an inlet-side pressure when the poppet is in the open position, wherein the outlet-side pressure is to decrease when the poppet is in the closed position, and wherein the bleed hole is configured to enable the chamber pressure to increase after the outlet-side pressure has increased and decrease after the outlet-side pressure has decreased.
A pressure relief valve for a cryogenic fuel tank, the pressure relief valve comprising:

a valve body including a valve seat, defining an inlet and an outlet, and at least partially defining a poppet chamber;

a poppet at least partially housed in the poppet chamber and configured to slide between a closed position and an open position, wherein the poppet includes:

a seat disc that includes a contact surface having a first outer diameter, wherein the contact surface is configured to engage the valve seat in the closed position to fluidly disconnect the outlet from the inlet and be disengaged from the valve seat in the open position to fluidly connect the outlet to the inlet; and

a poppet body having a second outer diameter that is greater than the first outer diameter, wherein the poppet body defines a bleed hole that fluidly connects the poppet chamber to the outlet in both the closed position and the open position such that a chamber pressure of cryogenic fluid in the poppet chamber is to equalize with an outlet-side pressure of the cryogenic fluid over time when the poppet is in the closed position or the open position; and

a spring at least partially housed in the poppet chamber and configured to bias the poppet toward the closed position,

wherein the poppet is configured to be positioned between the open position and the closed position based on a difference between an opening force and a closing force acting on the poppet with the first outer diameter defining a lower hysteresis threshold for opening the poppet and the second outer diameter defining an upper hysteresis threshold for closing the poppet,

wherein, in the closed position, the opening force is based on an inlet-side pressure and the first outer diameter of the contact surface of the seat disc,

wherein, in the open position, the opening force is based on the inlet-side pressure and the second outer diameter of the poppet body such that the opening force is to increase as the poppet transitions from the closed position to the open position, and

wherein the closing force equals a combination of a biasing force of the spring and a chamber-pressure force that corresponds with a chamber pressure of the cryogenic fluid in the poppet chamber and the second outer diameter of the poppet body.