Solenoid pilot valve for cryogenic fluids

Abstract

An electromagnetic pilot valve for cryogenic fluids is disclosed. An exemplary valve includes a body defining an inlet and an outlet. The valve includes a coil assembly coupled to the body. The valve includes a poppet configured to move parallel between a closed position and an open position. The poppet defines a pilot hole configured to fluidly connect the chamber to the outlet. The valve includes a plunger assembly disposed within the chamber. The plunger assembly includes a first plunger, disposed such that the coil assembly moves parallel to the first plunger. The plunger assembly includes a second plunger slidably coupled to the first plunger. The second plunger is configured to close the pilot hole in a second extended position and to open the pilot hole in a partially retracted position and a second retracted position.

Description

Technical Field

[0001] The present disclosure generally relates to solenoid valves, and more specifically to electromagnetic pilot valves for use with cryogenic fluids.

Background Art

[0002] Cryogenic control systems are configured to regulate the fluid within cryogenic cylinders or tanks. Generally, cryogenic cylinders contain a combination of liquid and gas at cryogenic temperatures (e.g., temperatures below minus 150 degrees Celsius (minus 238 degrees Fahrenheit)). For example, cryogenic tanks can contain a liquid (e.g., liquefied natural gas, liquid hydrogen) and a gas (e.g., natural gas, hydrogen) within a headspace above the liquid.

[0003] Often, valves are used to regulate the flow of fluid from cryogenic tanks. In some cases, cryogenic valves are solenoid valves. A solenoid valve can include an electromagnetic coil attached to a valve body. Some solenoid valves are normally open valves, which close when power is applied to the electromagnetic coil and open when power is removed. Other solenoid valves are normally closed valves, which open when power is applied to the electromagnetic coil and close when power is removed. Some normally closed valves for cryogenic fluids have difficulty forming a tightly sealed connection in the closed position, thereby allowing unintended outflow of cryogenic fluid from the cryogenic tank in the closed position.

Summary of the Invention

Means for Solving the Problems

[0004] An exemplary solenoid pilot valve for cryogenic fluids disclosed herein includes a valve body. The valve body includes a first seat and defines a conduit having an inlet and an outlet. The solenoid pilot valve includes a coil assembly coupled to the valve body. The solenoid pilot valve includes a poppet, which is configured to move parallel between a closed position (where the poppet is sealedly engaged with the first seat to fluidly separate the inlet and outlet) and an open position (where the poppet is disengaged from the first seat to fluidly connect the inlet and outlet). In the closed position, the poppet is sealedly engaged with the first seat to fluidly separate the inlet and outlet; in the open position, the poppet is disengaged from the first seat to fluidly connect the inlet and outlet. The poppet, valve body, and coil assembly define at least partially a chamber. The poppet defines a pilot hole configured to fluidly connect the chamber to the outlet. The poppet includes a second seat adjacent to the pilot hole. The solenoid pilot valve includes a plunger assembly located within a chamber. The plunger assembly includes a first plunger, configured to cause a coil assembly to move between a first extended position and a first retracted position relative to the first plunger. The plunger assembly includes a second plunger slidably coupled to the first plunger and extending toward the poppet. The second plunger is configured to move in parallel between a second extended position, a partially retracted position, and a second retracted position. The second plunger is configured to engage tightly with a second seat in the second extended position to close the pilot hole, and to disengage from the second seat in the partially retracted position and the second retracted position to open the pilot hole. [Brief explanation of the drawing]

[0005] [Figure 1] This is a cross-sectional view of an exemplary solenoid pilot valve for cryogenic fluids according to the teachings of this specification. [Figure 2] Figure 1 is a detailed cross-sectional view of the plunger assembly and poppet of the solenoid pilot valve in the closed state. [Figure 3] Figure 2 is a detailed cross-sectional view of the poppet. [Figure 4] Figure 2 shows the keyed surface of the poppet, and Figure 1 shows the keyed gasket of the solenoid pilot valve. [Figure 5] Figure 2 shows a detailed cross-sectional view of the upper plunger of the plunger assembly. [Figure 6] Detailed cross-sectional view of the lower plunger of the plunger assembly shown in Figure 2. [Figure 7] Figure 2 is a perspective view of the plunger assembly, with the body of the lower plunger in Figure 6 shown as transparent. [Figure 8] Figure 2 is a detailed cross-sectional view of the plunger assembly when the electromagnetic poppet valve in Figure 1 is in the closed or intermediate state. [Figure 9] Figure 2 is a detailed cross-sectional view of the plunger assembly when the electromagnetic poppet valve in Figure 1 is in the open position. [Figure 10] Figure 1 is a cross-sectional view of the electromagnetic poppet valve in the closed state. [Figure 11] Figure 1 is a cross-sectional view of the electromagnetic poppet valve in an intermediate state. [Figure 12] Figure 1 is a cross-sectional view of the electromagnetic poppet valve in the open state. [Figure 13] This is a cross-sectional view of another exemplary solenoid pilot valve for cryogenic fluids as taught herein. [Figure 14] Figure 13 is a cross-sectional view of the plunger assembly and poppet of the solenoid pilot valve in the closed state. [Modes for carrying out the invention]

[0006] The following description illustrates, illustrates, and illustrates one or more embodiments of the principles of the present invention. This description is not intended to limit the present invention to the embodiments described herein, but rather to explain and teach the principles of the present invention so that those skilled in the art can understand these principles and, based on that understanding, apply them not only to the embodiments described herein but also to other embodiments that can be conceived in accordance with these principles. This specification is intended to be taken as a whole and interpreted in accordance with the principles of the present invention taught herein and understood by those skilled in the art.

[0007] The scope of the present invention is intended to encompass all embodiments that may be included literally or under the doctrine of equivalents in the appended claims. While this specification describes exemplary embodiments, they are not intended to limit the claims or the invention described herein. Features described in the specification but not in the claims are not intended to limit the claims.

[0008] In the specification and drawings, identical or substantially similar elements are referred to by the same reference number. However, in some cases, these elements may be referred to by different numbers to facilitate clearer explanation. In addition, the drawings in this specification are not necessarily drawn to scale, and proportions may be exaggerated to more clearly illustrate certain components. Such notation and drawing methods are not necessarily intended to serve an essential purpose.

[0009] Some features may be described using relative terms such as top, bottom, vertical, right, and left. It should be understood that such relative terms are for reference only to the accompanying drawings. These relative terms are not intended to limit the embodiments disclosed.

[0010] Embodiments of solenoid pilot valves disclosed herein include a valve body, a coil assembly coupled to the valve body, a poppet, and a plunger assembly having a pilot hole. The coil assembly is configured to be energized and / or de-energized to cause movement of the plunger assembly, which in turn causes movement of the poppet. The poppet is configured to move in parallel between a closed position that prevents the flow of cryogenic fluid and an open position that allows the flow of cryogenic fluid. The solenoid pilot valve also includes one or more springs for biasing the poppet to the closed position.

[0011] Solenoid pilot valves are configured to form a tight, sealed connection in the closed state, preventing unintended leakage of cryogenic fluid through the valve. For example, one spring in a solenoid pilot valve has a relatively large closing force and is positioned to ensure that the plunger assembly and poppet form a sealed connection when the solenoid pilot valve transitions from the open to the closed state. To transition to the open state, the solenoid pilot valve must overcome the closing force of its spring.

[0012] To help the solenoid pilot valve overcome the closing force of the spring, the plunger assembly is a multi-plunger assembly that includes an upper plunger partially nested within a lower plunger. For example, when energized, the coil assembly pulls the upper and lower plungers together upward. When the lower plunger is pulled upward, it disengages from the poppet seat of the poppet, fluidly connecting the outlet side of the valve body to the pressure chamber in which the plunger assembly is located. As a result, the pressure in the pressure chamber becomes equal to the outlet pressure, which allows the lower plunger to slide upward relative to the upper plunger, the poppet to slide upward and disengage from the valve seat, and the solenoid pilot valve to open. In addition, to further help the solenoid pilot valve overcome the closing force of the spring, the stroke length of the upper plunger in the plunger assembly is relatively short. For example, the stroke length of a solenoid pilot valve for liquefied natural gas (LNG) is approximately 0.80 millimeters (0.031 inches), and the stroke length of a solenoid pilot valve for liquid hydrogen (LH2) is approximately 0.88 millimeters (0.035 inches).

[0013] In other words, embodiments of solenoid pilot valves disclosed herein include a spring with a relatively large closing force to ensure that the plunger forms a firm, sealed connection with the valve seat in the closed position. Since the solenoid pilot valve includes a multi-plunger assembly and incorporates an upper plunger with a relatively short stroke length, the solenoid pilot valve can overcome the closing force of the spring and, as a result, transition to the open position.

[0014] In addition, when the coil assembly is de-energized, the spring pushes the upper and lower plungers of the poppet and langer assembly downward with a relatively large closing force, ensuring that (1) the poppet forms a sealing seal with the valve seat, and (2) in the closed state, the lower plunger forms a sealing seal with the poppet seat. In embodiments disclosed herein, the poppet may also include a relatively small O-ring that can form a sealing seal with the valve seat without deformation even at cryogenic temperatures. Additionally or alternatively, the poppet seat can be formed of plastic, at least partially, to ensure a sealing seal between the lower plunger and the poppet seat in the closed state. Furthermore, in some such embodiments, the poppet seat is an insert that can be removed and replaced after prolonged use.

[0015] Referring to the drawings, Figure 1 shows an exemplary embodiment of a solenoid pilot valve 100 (hereinafter also referred to as the "valve" and the "pilot valve"). The valve 100 is configured to control the flow of a cryogenic fluid such as liquefied natural gas (LNG). The valve 100 in the illustrated embodiment includes a body 200 (also referred to as the "valve body"), a coil assembly 300, a poppet 400, and a plunger assembly 500.

[0016] The body 200 of the valve 100 includes a main body 210 that defines a conduit 215, an inlet port 220, and an outlet port 225. The conduit 215 extends between the inlet port 220 and the outlet port 225, and the outlet port 225 is in fluid communication with the inlet port 220 such that cryogenic fluid such as LNG can flow from the inlet port 220 to the outlet port 225. In some embodiments, the inlet port 220 and the outlet port 225 are threaded standard-sized fluid ports configured to receive fluid fittings. The conduit 215 includes an inlet side 230 adjacent to the inlet port 220 and an outlet side 235 adjacent to the outlet port 225. The inlet side 230 and the outlet side 235 are separated by a valve seat 240. The main body 210 includes a valve seat 240 (also referred to as the "first seat" or "first valve seat") disposed along the conduit 215 between the inlet port 220 and the outlet port 225. In the illustrated embodiment, the valve seat 240 is inclined. As will be described in detail below, the valve seat 240 is configured to sealingly engage with and disengage from the poppet 400. When the valve seat 240 sealingly receives the poppet 400, the outlet port 225 is fluidly isolated from the inlet port 220 and is configured to prevent cryogenic fluid from flowing through the conduit 215. When the poppet 400 disengages from the valve seat 240, the outlet port 225 is fluidly connected to the inlet port 220 and is configured to allow cryogenic fluid to flow through the conduit 215.

[0017] The main body 200 also includes a cartridge 250, which is coupled between the main body 210 and the coil assembly 300 and extends between them. For example, the cartridge 250 is screw-coupled to the main body 210 by threads. The cartridge 250 includes an integrally formed lower cartridge body 255 and an upper cartridge body 260. The lower cartridge body 255 is coupled to the main body 210 (e.g., screw-fit, press-fit). For example, a portion of the lower cartridge body 255 extends into and is housed within the main body 210 and coupled to the main body 210. The upper cartridge body 260 is coupled to the coil assembly 300 (e.g., screw-fit, press-fit). For example, a portion of the upper cartridge body 260 extends into and is housed within the housing 305 of the coil assembly 300 and coupled to the coil assembly 300.

[0018] In other words, the coil assembly 300 is coupled to the cartridge 250 of the main body 200. In the illustrated embodiment, the coil assembly 300 includes a housing 305, which includes a coil housing 310 and a wiring housing 315. The coil assembly 300 also includes a coil 320, which is housed in the coil housing 310 and configured to operate as an electromagnet. The wiring housing 315 houses wiring that is operationally connected to the coil 320. For example, control wiring transmits control signals for energizing or de-energizing the coil 320.

[0019] The coil housing 310 is a hollow cylinder and defines a hole 340 that extends along its longitudinal axis. The coil assembly 300 includes a plug 325 that is at least partially and firmly positioned inside it towards the upper end of the hole 340. The plug 325 is formed of a magnetic material. Further, since the plug 325 is disposed in the hole 340 of the coil housing 310 and is formed of a magnetic material, when the coil 320 is energized, the plug 325 generates a magnetic force that pulls the plunger 600 upward. The coil assembly 300 further includes a cap 330 and a seal 335. The cap 330 covers and seals the upper opening of the hole 340 of the coil housing 310. In the illustrated embodiment, the cap 330 is screwed and coupled to the plug 325 and sealingly engages with the housing 305 of the coil assembly 300. The seal 335 is configured to engage between the cap 330 and the housing 305 to form a sealed connection.

[0020] In addition, the cartridge 250 of the main body 200 is coupled to the housing 305 of the coil assembly 300. In the illustrated embodiment, the valve 100 includes a washer 910 disposed between the cartridge 250 and the housing 305 of the coil assembly 300. In the illustrated embodiment, the upper cartridge body 260 of the cartridge 250 extends at least into the hole 340 through the lower opening of the hole 340 of the coil housing 310. The upper cartridge body 260 can be firmly positioned relative to the coil assembly 300 by being press-fitted into the hole 340 of the coil housing 310. Further, the upper end of the upper cartridge body 260 engages with the lower end of the plug 325 within the hole 340 of the coil housing 310. In some embodiments, the upper cartridge body 260 of the cartridge 250 is fixedly coupled to the lower end of the plug 325 (e.g., by welding).

[0021] The poppet 400 of valve 100 is partially housed within the lower cartridge body 255 and extends downward beyond the cartridge 250. For example, the poppet 400 extends downward through the central opening of the lower cartridge body 255 of the cartridge 250. The upper part of the poppet 400 is housed within the lower cartridge body 255, and the lower part of the poppet 400 extends from the cartridge 250. As detailed below, the poppet 400 is configured to move in parallel between a closed position (see Figures 1 and 10-11) and an open position (see Figure 12). In the closed position, the poppet 400 engages tightly with the valve seat 240, fluidly separating the inlet side 230 and the outlet side 235, thereby blocking the flow of cryogenic fluid through the conduit 215 of valve 100. In the open position, the poppet 400 separates from the valve seat 240, fluidly connecting the inlet side 230 and outlet side 235 of the main body 200, allowing cryogenic fluid to flow through the conduit 215 of the valve 100.

[0022] In addition, the poppet 400, the body 200, and / or the coil assembly 300 define the chamber 265 (also called the “pressure chamber”). For example, the chamber 265 is defined at least partially by the cartridge 250 of the poppet 400 and the body 200. Furthermore, the chamber 265 is also defined by the plug 325 of the coil assembly 300. In other embodiments, the cartridge 250 can be shaped and positioned relative to the coil assembly 300, and the cartridge 250 and the poppet 400 are configured to combine to form the chamber 265. Furthermore, the gap formed between the poppet 400 and the plunger 700 allows various parts of the chamber 265 to be fluidly connected to one another. For example, a gap (e.g., a radial gap) formed between the poppet 400 and the plunger 700 fluidly connects the upper 266 and the middle 267 of the chamber 265, and another gap (e.g., a radial gap) formed between the poppet 400 and the plunger 700 fluidly connects the middle 267 and the lower 268 of the chamber 265. Furthermore, the poppet 400 is configured to be coaxially positioned with the plungers 600, 700 and the coil 320, and to move in parallel with them. Figure 2 further illustrates the arrangement of the poppet 400 relative to the plungers 600 and 700 in the plunger assembly 500.

[0023] Figure 3 further illustrates the poppet 400. In the illustrated embodiment, the poppet 400 includes a integrally formed upper body 410, a lower body 420, and a head 430. The upper body 410 (also called the “upper poppet body”) is located at the upper end of the poppet 400, and the head 430 (also called the “poppet head”) is located at the opposite lower end. The lower body 420 extends between the upper body 410 and the head 430 and is coupled to them. Referring to Figure 4, the lower body 420 has an outer flat or concave surface 465 which is configured to slidably engage with the inner flat or concave surface 935 of the gasket 930. The gasket 930 is firmly positioned within the body 200 of the valve 100 and is configured to slidably receive the poppet 400 in a keyed manner, preventing the poppet 400 from rotating around the longitudinal axis of the poppet 400 and / or the plunger assembly 500. For example, as shown in Figure 1, the gasket 930 is firmly positioned on the shelf portion 245 defined by one end of the lower cartridge body 255 and the main body 210.

[0024] Returning to Figure 3, the head 430 includes a seal 435 (e.g., an O-ring seal) configured to engage airtight with the valve seat 240 when the poppet 400 is in the closed position. As shown in Figure 1, when the coil 320 is de-energized, the poppet 400 is configured to remain in the closed position, in which case the seal 435 engages airtight with the valve seat 240, preventing the flow of cryogenic fluid through the conduit 215. The seal 435 is sized and shaped to prevent deformation at cryogenic temperatures, which could lead to a non-sealed state with the valve seat 240 in the closed position over time.

[0025] The upper body 410 is hollow and defines a cavity 415 configured to slidably receive the lower part of the plunger 700. The poppet 400 also includes a cap 440 coupled to the upper end of the upper body 410. The cap 440 is positioned to prevent the plunger 700 from tilting away from the longitudinal axis of the poppet 400 and / or the plunger assembly 500 as the plunger 700 slides within the cavity 415. In the illustrated embodiment, the cap 440 includes an annular groove configured to receive the upper end of the spring 820.

[0026] Furthermore, the upper body 410 and / or lower body 420 of the poppet 400 define a bore 425 extending from the lower end of the cavity 415. The bore 425 is configured to firmly receive the seat 450 of the poppet 400 (e.g., by press-fit). In the illustrated embodiment, the seat 450 (also called the “poppet seat,” “second seat,” or “second valve seat”) is an insert and includes a seal 455 and a retainer 460. That is, the seat 450 is an insert and can be removed from the bore 425 for maintenance and / or replacement. The seal 455 has an inverted T-shaped cross-section and is configured to engage with the plunger 700 (e.g., the ball 750 of the plunger 700) when the plunger 700 is in the extended position. The retainer 460 is circumferentially positioned around the seal 455 and engages with the seal 455. Furthermore, the retainer 460 is configured to engage with the upper body 410 and / or lower body 420 of the poppet 400 when the seat portion 450 is press-fitted into the bore 425. The seal 455 and retainer 460 are arranged such that the seat portion 450 has one or more sealing surfaces. For example, the seat portion 450 has a circumferential sealing surface, an upward-facing nose, and / or a lower sealing surface.

[0027] As shown in Figure 3, the poppet 400 defines a pilot hole 470. The pilot hole 470 extends from the head 430, through the lower body 420, to a cavity 415 defined by the upper body 410. The poppet 400 is positioned such that the upper end of the pilot hole 470 is fluidly connected to the chamber 265 via the cavity 415, and the lower end of the pilot hole 470 is fluidly connected to the outlet side 235 of the body 200 via the conduit 215. In addition, a seat 450 is positioned at the upper end of the pilot hole 470, and the seat 450 is adjacent to the pilot hole 470.

[0028] As detailed below, the pilot hole 470 allows the outlet side 235 of the body 200 to be fluidly connected to the chamber 265 when the plunger 700 disengages from the seat 450. In contrast, when the plunger 700 is sealedly engaged with the seat 450, the pilot hole 470 is closed, and the outlet side 235 and the chamber 265 are fluidly separated. The plunger 700 closes or opens the pilot hole 470 by engaging with or disengaging from the seat, respectively. As a result, the fluid pressure in the chamber 265 is controlled in such a way that the poppet 400 (1) transitions between a closed position and an open position and (2) forms a sealed seal with the valve seat 240 in the closed position.

[0029] The poppet 400 in the illustrated embodiment includes a circumferential groove 405 configured to receive a bleed seal 920. Returning to Figure 1, the bleed seal 920 separates the inlet side 230 of the conduit 215 from the chamber 265. That is, the bleed seal 920 defines the lower end of the chamber 265. The bleed seal 920 is configured to engage with the poppet 400 and the body 200. More specifically, the bleed seal 920 is configured to engage with the cartridge 250 of the poppet 400 and the body 200. The bleed seal 920 is positioned between the inlet side 230 of the conduit 215 and the chamber 265, forming an orifice that allows fluid to flow between the inlet side 230 and the chamber 265 at a relatively slow rate (e.g., bleed). For example, the bleed seal 920 can be dimensioned and positioned so that fluid can flow between the inlet side 230 and the chamber 265 at a controlled, predetermined rate. As a result, as detailed below, the bleed seal 920 is configured to allow the fluid pressure between the inlet side 230 and the chamber 265 to slowly equalize over time. For example, the bleed seal 920 is positioned between the poppet 400 and the body 200, and when the poppet 400 is in the closed position, it allows the pressure in the chamber 265 to slowly equalize over time with the pressure at the inlet side 230.

[0030] As shown in Figure 1, the solenoid 150 of the valve 100 is formed by a coil assembly 300 and a plunger assembly 500. The plunger assembly 500 is located within the chamber 265 and includes a plunger 600 (also called the "upper plunger" or "first plunger") and a plunger 700 (also called the "lower plunger" or "second plunger"). The plunger assembly 500 also includes a pin 800 configured to slidably connect the plunger 700 to the plunger 600.

[0031] The plunger 600 extends at least partially into the hole 340 through the lower opening of the hole 340 in the coil housing 310. In the illustrated embodiment, the plunger 600 is also at least partially housed within the upper cartridge body 260 of the cartridge 250. The plunger 600 is coaxially aligned with the coil 320 of the coil assembly 300. The plunger 600 is configured to move in parallel between an extended position (also called the “first extended position”) and a retracted position (also called the “first retracted position”). As will be detailed below, the coil 320 is configured to control the position of the plunger 600. More specifically, the plunger 600 is positioned relative to the coil assembly 300, and the coil 320 is configured to cause the plunger 600 to move in parallel between the extended position and the retracted position.

[0032] Referring to Figure 5, the plunger 600 in the illustrated embodiment includes an upper end 610 and a lower end 615 on the opposite side. The plunger 600 includes an upper body 620 adjacent to the upper end 610 and a lower body 625 adjacent to the lower end 615. The upper body 620 and the lower body 625 are integrally formed. The outer diameter of the upper body 620 is larger than the outer diameter of the lower body 625. The upper body 620 is sized to be securely and slidably received in the upper cartridge body 260 and / or coil housing 310. The lower body 625 is sized to be securely and slidably received in the plunger 700 (e.g., the cavity 705 of the plunger 700 in Figure 6). The plunger 600 defines a through hole 630 that extends along its entire length between the upper end 610 and the lower end 615. Furthermore, the through-hole 630 extends along the longitudinal axis of the plunger 600. As shown in Figure 1-2, the spring 810 of the valve 100 is configured to extend through the through-hole 630.

[0033] Returning to Figure 5, the plunger 600 defines opposing slots 640 (also called “vertical slots”) that extend laterally (e.g., vertically) to the through-hole 630. Each slot 640 extends vertically along the lower body 625 of the plunger 600. For example, each slot 640 includes a lower end 645 and an upper end 650 on the opposite side. As detailed below, the pin 800 extends through the slot 640 and is configured to connect the plunger 600 and the plunger 700. The slot is shaped to allow the plunger 700 to slide relative to the plunger 600 while maintaining the connected state. For example, the pin 800 is configured to slide from the lower end 645 to the upper end 650 of the slot 640, allowing the plunger 700 to move the plunger 600 in a parallel position to its retracted position. Conversely, the pin 800 is configured to slide from the upper end 650 to the lower end 645 of the slot 640 as the plunger 700 moves downward, allowing the plunger 700 to move the plunger 600 in parallel to the extended position.

[0034] Returning to Figure 1-2, plunger 600 is partially nested within plunger 700, which extends toward poppet 400. Plunger 700 extends at least partially into hole 340 through the lower opening of hole 340 in coil housing 310. Plunger 700 is also housed within cartridge 250. Plunger 700 is coaxially aligned with plunger 600 and coil 320. Plunger 700 is configured to translate between an extended position (also called the "second extended position"), a partially retracted position, and a fully retracted position (also called the "second retracted position").

[0035] Referring to Figure 6, the plunger 700 includes an upper body 710 adjacent to the upper end and a lower body 720 adjacent to the lower end. The upper body 710 and the lower body 720 are integrally formed. The outer diameter of the upper body 710 is larger than the outer diameter of the lower body 720. The upper body 710 is sized to fit securely and slidably into the upper cartridge body 260 and / or coil housing 310. The lower body 720 is sized to fit securely and slidably into the cavity 415 and / or cap 440 of the poppet 400.

[0036] The plunger 700 includes a ball 750 at its lower end. In the illustrated embodiment, the ball 750 is securely housed (e.g., by press-fit) in a cavity 730 positioned along the lower end of the plunger 700. The ball 750 is configured to engage tightly with the seat 450 when the plunger 700 is extended, and to disengage from the seat 450 when the plunger 700 is partially retracted and fully retracted. In some embodiments, the ball 750 is formed of a metallic material, and the seal 455 of the seat 450 is formed of a plastic material to help the plunger 700 form a consistent sealed connection with the seat 450. In addition, when the ball 750 engages with the seat 450, it tightly closes the pilot hole 470, fluidly separating the chamber 265 from the outlet side 235 of the valve 100. When the ball 750 detaches from the seat 450, it opens the pilot hole 470 and fluidly connects the chamber 265 to the outlet side 235 of the valve 100.

[0037] Furthermore, the plunger 700 defines a cavity 705 (also called the “first plunger cavity”) that extends from its upper end to its lower end. For example, the cavity 705 extends vertically along the length of the upper body 710 and also extends to part of the length of the lower body 720. The cavity 705 is configured to slidably receive the lower body 625 of the plunger 600, allowing the plungers 600 and 700 to be slidably coupled to each other. In addition, as is most clearly shown in Figures 2 and 8-9, the cavity 705 is configured to house the spring support 770 of the plunger 700. The spring support 770 includes a leg 775 at the lower end and a seat 780 at the opposite upper end. The leg 775 is configured to engage with and support the end of the spring 830, and the seat 780 is configured to engage with and support the end of the spring 810. In addition, the spring support 770 defines a through hole 785 through which the pin 800 extends.

[0038] Returning to Figure 6, the plunger 700 also has opposing holes 725 extending laterally (e.g., perpendicularly) to the cavity 705. As detailed below, each hole 725 is configured to receive the corresponding end of the pin 800, thereby slidably connecting the plungers 600 and 700 to one another. Furthermore, the plunger 700 includes a sleeve 740 configured to securely hold the pin 800 within the holes 725 and the slot 640. In the illustrated embodiment, the sleeve 740 extends circumferentially around the outer surface of the lower body 720 and engages with this outer surface. The sleeve 740 extends vertically from the lower end of the plunger 700 beyond the hole 725, covering the hole 725 in such a manner that it securely holds the pin 800 within the hole 725. The sleeve 740 is also positioned relative to the cap 440 of the poppet 400, forming a gap that fluidly connects the upper 266 and the middle 267 of the chamber 265.

[0039] As shown in Figure 7-9, plunger 700 is positioned relative to plunger 600, and its holes 725 are aligned with slots 640. Pins are inserted into each hole 725 of plunger 700, pass through each slot 640 of plunger 600, and pass through holes 785 of spring support 770 to securely connect plungers 600 and 700. More specifically, plunger 700 is slidably connected to plunger 600 by pins 800. Plunger 700 is configured to move in parallel with plunger 600 when plunger 700 moves from an extended position to a partially retracted position, and to slide relative to plunger 600 when plunger 700 moves from a partially retracted position to a fully retracted position. Figure 7-8 shows the plunger assembly 500 with the plunger 700 in the extended and / or partially retracted position, with the pin 800 engaged with the lower end 645 of the slot 640 of the plunger 600. Figure 9 shows the plunger assembly 500 with the plunger 700 in the retracted position, with the pin 800 engaged with the upper end 650 of the slot 640. The pin 800 is slidable vertically between the lower end 645 and the upper end 650 within the slot 640, allowing the plunger 700 to slide relative to the plunger 600.

[0040] Returning to Figure 1, the valve 100 includes one or more springs configured to bias the poppet 400 and / or plunger 700 in a particular direction. For example, the valve 100 includes spring 810 (also called the “first spring”), spring 820 (also called the “second spring”), and spring 830 (also called the “third spring”).

[0041] The spring 810 extends through the through-hole 630 of the plunger 600. Furthermore, the spring 810 extends between the plug 325 of the coil assembly 300 and the seat 780 of the spring support 770 (Figure 2) of the plunger 700 and engages with them. The spring 810 is positioned to bias the plunger 700 toward its extended position and close the pilot hole 470, and / or bias the poppet 400 toward its closed position and close the conduit 215. For example, as detailed below, the spring 810 is configured to push the plunger 700 from its fully retracted position to its extended position and to engage tightly with the seat 450.

[0042] The spring 820 is located within the cavity 415 of the poppet 400. Furthermore, the spring 820 extends between the cap 440 of the poppet 400 and the leg 745 of the plunger 700 and engages with them. The spring 820 is positioned to (1) bias the plunger 700 downward and hold it in its extended position when the valve 100 is in the closed position, (2) allow the poppet 400 to open when the valve 100 is in the intermediate position, and / or (3) bias the poppet 400 upward when the plunger 700 is in the fully retracted position, thereby holding the poppet 400 in the open position when the valve 100 is in the closed position. Furthermore, the leg 745 is located within the cavity 415 and is positioned relative to the upper body 410 of the poppet 400, forming a gap that fluidly connects the middle section 267 and the lower section 268 of the chamber 265.

[0043] The spring 830 extends between the lower end 615 of the plunger 600 and the leg 775 of the spring support 770 (Figure 2) of the plunger 700 and engages with them. The spring 830 is positioned to bias the plunger 600 upward toward its extended position when the plunger 700 is in its extended position. The spring 830 holds the plunger 600 in its extended position to prevent it from moving downward in parallel when the coil 320 is de-energized.

[0044] Figures 10-12 show the valve 100 in various operating states. Specifically, Figure 10 shows the valve 100 in a closed state, Figure 11 shows the valve 100 in an intermediate state, and Figure 12 shows the valve 100 in an open state. The coil 320 of the coil assembly 300 is configured to transition between energized and de-energized states, causing the valve 100 to transition between a closed state and an open state, respectively. That is, the valve 100 is configured to transition from a closed state to an open state when the coil 320 of the coil assembly 300 transitions to an energized state. Conversely, the valve 100 is configured to transition from an open state to a closed state when the coil 320 of the coil assembly 300 transitions to a de-energized state.

[0045] Referring to Figure 10, valve 100 is in the closed position, and coil 320 of coil assembly 300 is de-energized. When coil 320 is de-energized, it does not generate a magnetic field that has an upward force (e.g., about 15 N) pulling plunger 600 upward. As a result, the biasing force of spring 810 pushes plunger 700 to the extended position, and consequently poppet 400 is held in the closed position. That is, when valve 100 is in the closed position, poppet 400 is in the closed position, sealingly engaging with valve seat 240, fluidly separating the inlet side 230 and outlet side 235, preventing cryogenic fluid from flowing through conduit 215. In addition, plunger 700 is in the extended position, and the ball 750 of plunger 700 seally engages with seat 450 to close the pilot hole, fluidly separating chamber 265 and outlet side 235. Furthermore, when the poppet 400 and plunger 700 are in the closed and extended positions, respectively, the biasing force of the spring 830 causes the plunger 600 to slide upward relative to the plunger 700 until the pin 800 contacts the lower end 645 of the slot 640 (at which point the plunger 600 is in the extended position). When the plunger 600 is in the extended position, a gap 270 is formed between the plunger 600 and the plug 325 of the coil assembly 300. The gap 270 is relatively small, for example, about 0.031 inches. In addition, when the plungers 600 and 700 are in the extended positions, a gap 275 is formed between the upper body 620 of the plunger 600 and the upper body 710 of the plunger 700. The gap 275 is relatively small, for example, about 0.173 inches.

[0046] When valve 100 is in the closed position, the inlet pressure of the cryogenic fluid at the inlet side 230 of conduit 215 is greater than the outlet pressure of the cryogenic fluid at the outlet side 235 of conduit 215. Furthermore, the inlet pressure of the cryogenic fluid at the inlet side 230 is greater than or equal to the chamber pressure of the fluid in chamber 265. For example, immediately after the valve transitions to the closed position, the inlet pressure at the inlet side 230 is higher than the chamber pressure in chamber 265. Over time, as valve 100 remains closed, the bleed seal 920 allows the fluid to slowly seep between the inlet side 230 and chamber 265. As a result, the chamber pressure in chamber 265 gradually rises until it equals the inlet pressure at the inlet side 230, which substantially facilitates the transition of valve 100 from the closed position. As the chamber pressure in chamber 265 rises, the chamber pressure becomes higher than the outlet pressure, and the poppet 400 is held further closed.

[0047] Figure 11 shows the valve 100 in an intermediate state. To transition the valve 100 from a closed state (Figure 10) to an intermediate state (Figure 11), the coil 320 of the coil assembly 300 is energized. When the coil 320 is energized, it generates a magnetic field, which pulls the plunger 600 upward to its retracted position. As shown in the illustrated embodiment, the plunger 600 engages with the plug 325 of the coil assembly 300 in the retracted position, and the gap 270 becomes zero. In addition, the magnetic field of the coil 320 initially pulls the plungers 600 and 700 together upward, so the plunger 700 moves to a partially retracted position. That is, the plungers 600, 700 and the pin 800 are arranged such that when the coil 320 is energized, the plunger 700 moves upward in parallel with the plunger 600. For example, the plungers 600 and 700 and the springs 810 and 820 are arranged such that the biasing force of the springs 810 and 820 is canceled out by the force that the coil 320 applies to the plunger 600, and the plunger 700 moves upward together with the plunger 600. As a result, a gap 275 is maintained between the upper body 620 of the plunger 600 and the upper body 710 of the plunger 700.

[0048] Simultaneously, when coil 320 is energized, the poppet 400 is initially positioned to remain in the closed position due to the chamber pressure in chamber 265 being greater than the outlet pressure and / or the biasing force of spring 820 being relatively weak. As a result, the poppet 400 engages tightly with valve seat 240, fluidly separating the outlet side 235 and the inlet side 230, thus still preventing the cryogenic fluid from flowing through conduit 215. When plunger 700 is in a partially retracted position and poppet 400 remains in the closed position, the ball 750 of plunger 700 disengages from seat 450, fluidly connecting chamber 265 and outlet side 235 through the opening of pilot hole 470.

[0049] When the pilot hole 470 is open and the valve 100 is in the intermediate position, the chamber pressure in the chamber 265 decreases to equal the outlet pressure. For example, immediately after the valve moves to the intermediate position, the chamber pressure in the chamber 265 decreases, and the inlet pressure at the inlet side 230 becomes higher than the chamber pressure. Both the inlet pressure at the inlet side 230 and the chamber pressure in the chamber 265 remain higher than the outlet pressure at the outlet side 235. Over time, the chamber pressure in the chamber 265 decreases to a predetermined threshold, at which point the poppet 400 can push the plunger 700 toward the open position.

[0050] Figure 12 shows the valve 100 in the open position, where the plunger 600 remains in the retracted position, the plunger 700 is in the retracted position, and the poppet 400 is in the open position. The ball 750 of the plunger 700 remains detached from the seat 450, maintaining a fluidic connection between the chamber 265 and the outlet side 235 of the conduit 215. In addition, the poppet 400 detaches from the valve seat 240, fluidically connecting the outlet side 235 and the inlet side 230 of the conduit 215. As a result, when the valve 100 is in the open position, the cryogenic fluid can flow through the conduit 215. When the poppet 400 is open and the cryogenic fluid can flow through the conduit 215, the inlet pressure at the inlet side 230 is greater than or equal to the outlet pressure at the outlet side 235.

[0051] To move the valve 100 from an intermediate state (Figure 11) to an open state (Figure 12), the coil 320 of the coil assembly 300 remains energized. As a result, the plunger 700 remains detached from the seat 450, and the chamber 265 remains fluidly connected to the outlet side 235 via the pilot hole 470. Meanwhile, the chamber pressure in the chamber 265 decreases toward the outlet pressure of the outlet side 235. Finally, when the chamber pressure in the chamber 265 decreases to a predetermined pressure threshold, the pressure difference between the inlet pressure of the inlet side 230 and the chamber pressure in the chamber 265 pushes the poppet 400 upward, detaching it from the valve seat 240 and moving it in parallel to its open position. As a result, the poppet 400 pushes the plunger 700 upward to a position where it is fully retracted relative to the plunger 600.

[0052] For example, when coil 320 is initially energized and valve 100 moves to an intermediate state, electromagnetic forces act on both plunger 600 and plunger 700. Because plunger 600 is located higher and adjacent to plug 325, a greater magnetic force is applied to plunger 600 than to plunger 700. As a result, the gap 275 remains unchanged as plunger 600 moves upward toward plug 325 because the electromagnetic force acting on plunger 700 is not strong enough to overcome the biasing force of spring 810 and / or spring 820. When poppet 400 moves upward as valve 100 moves to an open state, poppet 400 pushes plunger 700 upward relative to plunger 600. When poppet 400 is in the open position, plunger 700 is very close to the position of plunger 600. As a result, the magnetic force acting on the plunger 700 increases, causing the plunger 700 to continue moving to its fully retracted position. When the plunger 700 is in its fully retracted position, it is positioned close to the coil 320, and the magnetic force of the coil 320 holds the plunger 700 in its fully retracted position.

[0053] In some embodiments, a predetermined pressure threshold corresponds at least partially to the biasing force(s) of spring 810, spring 820, and / or spring 830. The differential pressure between the outlet pressure and the chamber pressure overcomes the biasing force(s) of one or more of the springs 810, 820, and 830, causing the plunger 700 to slide upward relative to the plunger 600. Furthermore, when the plunger 700 is fully retracted, the gap 275 between the upper body 620 of the plunger 600 and the upper body 710 of the plunger 700 becomes zero. The differential pressure between the inlet pressure and the chamber pressure overcomes the biasing force(s) of one or more of the springs 810, 820, and 830, causing the plunger 700 to slide upward relative to the plunger 600. In this open position, the upper end of the poppet 400 engages with the cartridge 250 of the body 200. For example, the poppet 400 is configured to move a distance of approximately 0.177 inches between the closed and open positions.

[0054] Subsequently, when the coil 320 is de-energized, the biasing force of the spring 810 pushes the poppet 400 from the open position to the closed position with sufficient force, so that a sealed connection is formed between the seal 435 and the valve seat 240. That is, the spring 810 pushes the poppet 400 so that it engages sealily with the valve seat 240 of the body 200. As a result, the poppet 400 fluidly separates the outlet side 235 from the inlet side 230, again preventing the cryogenic fluid from passing through the conduit 215. Furthermore, the biasing force of the spring 810 pushes the plunger 700 from the fully retracted position to the extended position with sufficient force, so that a sealed connection is formed between the ball 750 of the plunger 700 and the seat 450 of the poppet 400. As a result, the plunger assembly 500 fluidly separates the outlet side 235 from the chamber 265 in order to hold the poppet 400 closed until the coil 320 is energized again.

[0055] The plunger assembly 500 in the illustrated embodiment is configured to ensure that a sealed connection is formed between the poppet 400 and the valve seat 240 when the valve moves from the open to the closed position. For example, the plunger assembly 500 includes two plungers, 600 and 700, which are slidably coupled to minimize the working distance of plunger 600 (e.g., equal to the length of the gap 270). By reducing the working distance of plunger 600, the magnetic force generated by coil 320 (e.g., about 15 N) overcomes the greater biasing force of spring 810, allowing the valve 100 to move from the closed to the open position. As a result, spring 810 can have a greater biasing force, which, when the valve 100 moves to the closed position, biases the poppet 400 to the closed position, helping the poppet 400 to consistently form a sealed connection with the valve seat 240.

[0056] Figure 13 shows another embodiment of valve 1000 (also called a “solenoid pilot valve”). Valve 1000 is configured to control the flow of a cryogenic fluid such as liquid hydrogen (LH2). Valve 1000 includes the same or substantially similar components as valve 100. For example, valve 1000 includes body 1200, coil assembly 1300, plunger assembly 1500, springs 1810, 1820, 1830, and bleed seal 1920, respectively, which are the same or substantially similar as body 200, coil assembly 300, plunger assembly 500, springs 1810, 1820, 1830, and bleed seal 1920 of valve 100. Furthermore, the plunger assembly 1500 includes plungers 1600, 1700, and 1800, which are identical or substantially similar to the plungers 600, 700, and 800 of the valve 100, respectively. Therefore, some of the features of these components of the valve 1000 will not be described in detail below.

[0057] Figure 14 further shows the poppet 1400 of valve 1000 when assembled with the plunger assembly 1500. The poppet 1400 is configured to operate identically or substantially similarly to the poppet 400 of valve 100. Therefore, some of the features relating to these operations of the poppet 1400 will not be described in detail again below. Furthermore, the poppet 1400 includes identical or substantially similar components to those of the poppet 400. For example, the poppet 1400 includes an upper body 1410, cavity 1415, lower body 1420, bore 1425, head 1430, seal 1435, cap 440, seat 450, and pilot hole 1470, which are identical or substantially similar to the upper body 410, cavity 415, lower body 420, bore 425, head 430, seal 435, cap 440, seat 1450, and pilot hole 1470 of the poppet 400, respectively. Therefore, some of the features of these components of the valve 1000 will not be described in detail again below.

[0058] As shown in Figure 14, the poppet 1400 also includes a winged flange 1480 extending radially outward from the lower body 1420. The winged flange defines one or more circumferential grooves 1405, each receiving a corresponding bleed seal 1920. Furthermore, the poppet 1400 includes an insert 1490 configured to be firmly inserted into the lower end of a pilot hole 1470 adjacent to the head 1430. In the illustrated embodiment, the insert 1490 includes one or more legs 1495 extending downward beyond the head 1430 of the poppet 1400.

[0059] An exemplary solenoid pilot valve for cryogenic fluids includes a valve body. The valve body includes a first seat and defines a conduit having an inlet and an outlet. The solenoid pilot valve includes a coil assembly coupled to the valve body. The solenoid pilot valve includes a poppet, which is configured to move in parallel between a closed position (where the poppet is sealedly engaged with the first seat to fluidly separate the inlet and outlet) and an open position (where the poppet is disengaged from the first seat to fluidly connect the inlet and outlet), in the closed position the poppet is sealedly engaged with the first seat to fluidly separate the inlet and outlet, and in the open position the poppet is disengaged from the first seat to fluidly connect the inlet and outlet. The poppet and valve body define at least partially a chamber. The poppet defines a pilot hole configured to fluidly connect the chamber and the outlet. The poppet includes a second seat adjacent to the pilot hole. The solenoid pilot valve includes a plunger assembly located within a chamber. The plunger assembly includes a first plunger, configured to cause a coil assembly to move between a first extended position and a first retracted position relative to the first plunger. The plunger assembly includes a second plunger slidably coupled to the first plunger and extending toward the poppet. The second plunger is configured to move in parallel between a second extended position, a partially retracted position, and a second retracted position. The second plunger is configured to engage tightly with a second seat in the second extended position to close the pilot hole, and to disengage from the second seat in the partially retracted position and the second retracted position to open the pilot hole.

[0060] In some embodiments, the valve body further includes a main body including a first seat, an inlet side, and an outlet side. The valve body further includes a cartridge extending between the main body and a coil assembly and coupled thereto. The cartridge, at least partially together with the poppet, defines the chamber.

[0061] In some embodiments, the coil assembly includes a coil configured to position a first plunger in a first extended position when de-energized and in a first retracted position when energized.

[0062] In some embodiments, the second plunger includes a ball configured to engage in a sealed manner with the second seat of the poppet when the second plunger is in a second extended position.

[0063] In some embodiments, the plunger assembly further includes a pin configured to slidably connect a second plunger to the first plunger. In some such embodiments, the pin is fixed to the second plunger. The first plunger defines a vertical slot, and the pin extends slidably through the vertical slot, allowing the second plunger to slide relative to the first plunger. The vertical slot includes an upper and a lower end. The pin is configured to slide from the lower end to the upper end as the second plunger moves in parallel to the second retracted position and the poppet moves in parallel to the open position.

[0064] In some embodiments, a bleed seal is further included, which is positioned between the poppet and the valve body, and when the poppet is in the closed position, causes the pressure inside the chamber to gradually equalize with the pressure inside the valve body over time.

[0065] In some embodiments, the system further includes a first spring extending between and engaging with the coil assembly and the second plunger for biasing the second plunger to a second extended position and the poppet to a closed position. In some embodiments, the system further includes a second spring extending between and engaging with the second plunger and the poppet for further biasing the second plunger toward a second extended position. In some embodiments, the system further includes a third spring extending between and engaging with the first plunger and the second plunger for biasing the first plunger toward a first extended position when the second plunger is in a second extended position.

[0066] In some embodiments, when the solenoid pilot valve is closed, the poppet is in the closed position and seally engages with the first seat to fluidly separate the inlet and outlet sides of the valve body; the first plunger is in the first extended position; the second plunger is in the second extended position and seally engages with the second seat to fluidly separate the chamber from the outlet side of the valve body; the inlet pressure is greater than the outlet pressure and also greater than or equal to the chamber pressure of the chamber.

[0067] In some embodiments, when the solenoid pilot valve is in an intermediate state, the poppet is in the closed position, sealedly engaged with the first seat to fluidly separate the inlet and outlet sides of the valve body, the first plunger is in the first retracted position, and the second plunger is in a partially retracted position, disengaged from the second seat to fluidly connect the chamber and the outlet side, allowing the chamber to become uniform with the outlet side, the inlet pressure being greater than the chamber pressure inside the chamber, and furthermore, the chamber pressure being greater than or equal to the outlet pressure on the outlet side.

[0068] In some embodiments, the solenoid pilot valve is configured to transition from a closed state to an intermediate state when the coil assembly transitions to an energized state. The coil assembly transitioning to an energized state is configured to cause the first plunger to move in parallel to a first retracted position and the second plunger to move in parallel to a partially retracted position.

[0069] In some embodiments, when the solenoid pilot valve is open, the poppet is in the open position, disengaged from the first seat and fluidly connecting the inlet and outlet sides of the valve body; the first plunger is in the first retracted position; the second plunger is in the second retracted position, disengaged from the second seat and fluidly connecting the chamber and outlet side; and the inlet pressure is greater than or equal to the outlet pressure.

[0070] In some embodiments, the electromagnetic pilot valve is configured to transition from an intermediate state to an open state when the coil assembly remains energized, the chamber pressure in the chamber drops to a predetermined pressure threshold, and the differential pressure between the chamber pressure and the inlet pressure pushes the poppet upward, causing it to detach from the first seat and move parallel to the open position.

[0071] In some embodiments, the solenoid pilot valve is configured to move from a closed to an open state in response to the coil assembly transitioning to an energized state. Some such embodiments further include a spring configured to push a poppet from an open to a closed position and seally engage with a first seat of the valve body when the coil assembly transitions to an unenergized state.

Claims

1. A valve body having a first seat and defining a conduit having an inlet side and an outlet side, A coil assembly coupled to the valve body, A poppet configured to move in parallel between a closed position and an open position, wherein in the closed position, the poppet engages tightly with a first seat to fluidly separate the inlet side from the outlet side, and in the open position, the poppet disengages from the first seat to fluidly connect the inlet side and the outlet side, the poppet and the valve body define at least partially a chamber, the poppet defines a pilot hole configured to fluidly connect the chamber and the outlet side, and the poppet includes a second seat adjacent to the pilot hole, A plunger assembly disposed within the chamber, An electromagnetic pilot valve for cryogenic fluids, comprising: The plunger assembly is A first plunger, wherein the coil assembly is configured to cause the first plunger to move parallel to the first plunger between a first extended position and a first retracted position, A second plunger is slidably coupled to the first plunger and extends toward the poppet, Equipped with, The second plunger is configured to move in parallel between a second extended position, a partially retracted position, and a second retracted position, wherein the second plunger is configured to engage tightly with the second seat in the second extended position to close the pilot hole, and to disengage from the second seat in the partially retracted position and the second retracted position to open the pilot hole. Solenoid pilot valve.

2. The valve body is The main body includes the first seat portion, the entrance side, and the exit side, A cartridge extending between the main body and the coil assembly and coupled thereto, It further includes, The solenoid pilot valve according to claim 1, wherein the cartridge defines the chamber together with the poppet, at least partially.

3. The electromagnetic pilot valve according to claim 1, wherein the coil assembly includes a coil configured to position the first plunger in a first extended position when de-energized and in a first retracted position when energized.

4. The solenoid pilot valve according to claim 1, wherein the second plunger includes a ball configured to engage in a sealed manner with the second seat of the poppet when the second plunger is in the second extended position.

5. The solenoid pilot valve according to claim 1, wherein the plunger assembly further includes a pin configured to slidably connect the second plunger to the first plunger.

6. The solenoid pilot valve according to claim 5, wherein the pin is fixed to the second plunger, the first plunger defines a vertical slot through which the pin extends slidably, allowing the second plunger to slide relative to the first plunger, the vertical slot having an upper and a lower end, and the pin is configured to slide from the lower end to the upper end when the second plunger moves parallel to the second retracted position and the poppet moves parallel to the open position.

7. The solenoid pilot valve according to claim 1, further comprising a bleed seal disposed between the poppet and the valve body, which, when the poppet is in the closed position, causes the pressure inside the chamber to gradually equal the pressure inside the valve body over time.

8. A first spring extending between the coil assembly and the second plunger and engaging with them, for biasing the second plunger to the second extended position and the poppet to the closed position, A second spring extending between the second plunger and the poppet and engaging with them, for further biasing the second plunger toward the second extended position, A third spring extending between and engaging with the first plunger and the second plunger, for biasing the first plunger toward the first extended position when the second plunger is in the second extended position, The electromagnetic pilot valve according to claim 1, further comprising:

9. When the solenoid pilot valve is in the closed position, The poppet, in the closed position, engages in a sealed manner with the first seat, thereby fluidly separating the inlet side and the outlet side of the valve body. The first plunger is in the first extended position, The second plunger is in the second extended position and engages in a sealed manner with the second seat to fluidly separate the chamber from the outlet side of the valve body. The solenoid pilot valve according to claim 1, wherein the inlet pressure on the inlet side is greater than the outlet pressure on the outlet side, and is also greater than or equal to the chamber pressure of the chamber.

10. When the solenoid pilot valve is in an intermediate state, The poppet, in the closed position, engages in a sealed manner with the first seat, thereby fluidly separating the inlet side and the outlet side of the valve body. The first plunger is in the first retracted position, The second plunger is in the partially retracted position, detached from the second seat, and fluidly connects the chamber and the outlet side, allowing the chamber to become uniform with the outlet side. The solenoid pilot valve according to claim 1, wherein the input pressure on the input side is greater than the chamber pressure in the chamber, and furthermore, the chamber pressure is greater than or equal to the outlet pressure on the outlet side.

11. The solenoid pilot valve according to claim 1, wherein when the coil assembly transitions to an energized state, the solenoid pilot valve is configured to transition from a closed state to an intermediate state, and the coil assembly transitioning to the energized state is configured to move the first plunger to the first retracted position and the second plunger to the partially retracted position as a single unit in parallel.

12. When the solenoid pilot valve is in the open position, The poppet, in the open position, detaches from the first seat and fluidly connects the inlet side and the outlet side of the valve body. The first plunger is in the first retracted position, The second plunger is in the second retracted position, detached from the second seat, and fluidly connects the chamber and the outlet side. The solenoid pilot valve according to claim 1, wherein the inlet pressure on the inlet side is equal to or greater than the outlet pressure on the outlet side.

13. The aforementioned solenoid pilot valve is The coil assembly remains energized, and When the chamber pressure drops to a predetermined pressure threshold, the poppet is pushed upward by the pressure difference between the chamber pressure inside the chamber and the inlet pressure on the inlet side, causing it to detach from the first seat and move parallel to the open position. The electromagnetic pilot valve according to claim 1, configured to transition from an intermediate state to an open state.

14. The solenoid pilot valve according to claim 1, wherein the solenoid pilot valve is configured to transition from a closed state to an open state in response to the coil assembly transitioning to an energized state.

15. The electromagnetic pilot valve according to claim 14, further comprising a spring configured to push the poppet from the open position to the closed position and to engage in a sealed manner with the first seat of the valve body when the coil assembly transitions to a non-energized state.

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