LNG (Liquefied Natural Gas) drainage one-way valve

Abstract

The utility model relates to an LNG (Liquefied Natural Gas) drainage one-way valve, which solves the technical problems that the existing drainage one-way valve for a vehicle-mounted LNG pump is complicated in product structure, large in occupied space, poorer in shock resistance and inconvenient to overhaul and replace parts. The one-way valve comprises a one-way valve shell. A shell through hole is formed in the one-way valve shell and comprises a first through hole section, a second through hole section and a third through hole section, and the inner diameters of the first through hole section, the second through hole section and the third through hole section are sequentially increased. A valve element is installed on the second through hole section and comprises a valve element spherical section, a valve element limiting section and a valve element guiding section. The third through hole section is provided with a spring pressing cylinder; the spring pressing cylinder comprises a pressing cylinder guide section, a pressing cylinder thread section and a pressing cylinder pin hole section; the periphery of the valve element guide section is sleeved with a spring. A pin is arranged in the pin hole section of the pressing cylinder; the pressure cylinder guide section is sleeved on the valve core guide section; an inner conical surface is arranged on the inner wall of the pressing cylinder pin hole section, and an engagement structure is arranged on the periphery of the pressing cylinder pin hole section and used for achieving fastening of the pressing cylinder pin hole section and the third through hole section in a matched mode.

Description

Technical Field

[0001] This utility model relates to a vehicle-mounted LNG check valve, specifically an LNG discharge check valve. Background Technology

[0002] In recent years, the natural gas vehicle industry has developed rapidly, leading to a continuous increase in demand for on-board LNG pump valve components. Among them, the drain check valve, as a key component of the LNG cryogenic high-pressure pump, directly affects the working efficiency of the LNG cryogenic high-pressure pump.

[0003] Drainage check valves typically need to meet requirements such as low flow resistance, low leakage, small size, good shock resistance, and rapid opening and closing. Existing LNG high-pressure cryogenic drainage check valves have complex structures, are inconvenient for maintenance and parts replacement, have insufficient shock resistance, short lifespan, and are not suitable for long-term vehicle use. Utility Model Content

[0004] The purpose of this utility model is to solve the technical problems of existing LNG pump drain check valves, such as complex product structure, large space occupation, poor impact resistance, and inconvenience in maintenance and parts replacement, and to provide an LNG drain check valve.

[0005] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0006] An LNG discharge check valve for use in LNG cryogenic high-pressure pumps for discharge;

[0007] Its special feature is:

[0008] Including the one-way valve housing;

[0009] The one-way valve housing is a cylindrical housing, and its inner hole includes a first through hole section, a second through hole section and a third through hole section arranged coaxially from bottom to top. The inner diameters D11, D12 and D13 of the first through hole section increase sequentially. The first through hole section is used to connect to the input end of the LNG cryogenic high-pressure pump.

[0010] A valve core is installed inside the one-way valve housing. The valve core includes a valve core spherical section, a valve core limiting section, and a valve core guide section connected sequentially from bottom to top. The valve core guide section has a valve core inner hole with one end communicating with the inner hole of the one-way valve housing. The valve core limiting section has at least one valve core through hole communicating with its outer surface and the other end of the valve core inner hole.

[0011] The maximum outer diameter D21 of the spherical section of the valve core, the maximum outer diameter D22 of the limiting section of the valve core, and the outer diameter D23 of the guiding section of the valve core satisfy the relationship: D12 ≥ D22 > D21 > D11, and D12 ≥ D22 > D23 > D11, such that an upward first step surface is formed between the first through - hole section and the second through - hole section, and an upward second step surface for limiting is formed between the outer surfaces of the limiting section and the guiding section of the valve core;

[0012] A spring cylinder is installed in the third through - hole section. The inner hole of the spring cylinder includes a cylinder guiding section, a cylinder threaded section, and a cylinder pin - hole section that are connected in sequence from bottom to top; the inner diameter D41 of the cylinder guiding section, the inner diameter D42 of the cylinder threaded section, and the minimum inner diameter D43 of the cylinder pin - hole section satisfy the conditions: D42 < D41 and D42 < D43; the cylinder guiding section is sleeved on the guiding section of the valve core;

[0013] A spring is sleeved on the outer circumference of the guiding section of the valve core. The upper end of the spring abuts against the lower end surface of the cylinder guiding section, and the lower end of the spring abuts against the second step surface;

[0014] A hollow pin is arranged in the cylinder pin - hole section. The outer circumferential surface of the pin is an outer conical table surface with the small end downward; the inner circumferential surface of the cylinder pin - hole section is an inner conical table surface with the small end downward; the inner conical table surface of the cylinder pin - hole section is in interference fit with the outer conical table surface of the pin, and a biting structure is provided on the outer circumferential surface of the cylinder pin - hole section for realizing the fastening of the cylinder pin - hole section and the third through - hole section;

[0015] Furthermore, the limiting section of the valve core includes a frustum section with the small end downward and connected to the spherical section of the valve core, and a cylindrical section coaxially connected to the large end of the frustum section and the lower end of the guiding section of the valve core respectively;

[0016] The outer circumferential surface of the frustum section is an arc concave surface;

[0017] The valve - core through - hole is arranged on the frustum section;

[0018] The maximum outer diameter D22 of the limiting section of the valve core is the outer diameter of the cylindrical section.

[0019] Furthermore, the first step surface is a conical table surface with the small end downward.

[0020] Furthermore, the outer diameters of the cylinder guiding section, the cylinder threaded section, and the cylinder pin - hole section are adapted to the inner diameter D13 of the third through - hole section;

[0021] A cylinder boss extending downward into the second through - hole section is provided below the cylinder guiding section. The cylinder boss is sleeved on the upper end of the guiding section of the valve core, and the outer diameter of the cylinder boss is adapted to the inner diameter D12 of the second through - hole section;

[0022] The upper end of the spring abuts against the lower end surface of the cylinder guiding section through the cylinder boss.

[0023] Furthermore, the outer diameter D22 of the cylindrical section of the valve core limiting section is adapted to the inner diameter D12 of the second through hole section, which is used to combine with the pressure cylinder boss to achieve a seal on the spring.

[0024] Furthermore, the engagement structure of the pressure cylinder pin hole section consists of at least three annular grooves on its outer surface; the at least three annular grooves are evenly distributed side by side along its axial direction.

[0025] Furthermore, the inner wall of the threaded section of the pressure cylinder is provided with an internal thread for mating with external mounting fixtures;

[0026] The inner wall of the pin has internal threads for mating with external mounting fixtures.

[0027] Furthermore, the inner diameter D24 of the valve core inner hole, the inner diameter D42 of the pressure cylinder thread section, and the inner diameter D51 of the pin inner hole are all equal to the inner diameter D11 of the first through hole section.

[0028] Furthermore, the lower outer periphery of the one-way valve housing is provided with an inlet connection thread for connecting to external equipment, and the upper outer periphery is provided with an outlet connection thread for connecting to external equipment.

[0029] Furthermore, the one-way valve housing, valve core, spring cylinder, spring, and pin are all made of metal materials.

[0030] The advantages of this utility model compared to the prior art are:

[0031] 1. This utility model provides an LNG discharge check valve, designed based on the requirements of LNG pump discharge check valves for vehicles. It employs a combination of valve core, spring cylinder, pin, and spring, simplifying the check valve structure and reducing its space occupation while achieving LNG pump discharge for vehicles. The valve is also compact and allows for rapid opening and closing. Furthermore, it reduces the difficulty of maintenance and parts replacement.

[0032] 2. The LNG discharge check valve provided by this utility model has a tensioned sealing structure between the spring cylinder and the check valve housing. The outer wall surface of the upper end of the spring cylinder is provided with an annular groove. The installation is completed by squeezing and deforming the outer wall groove of the spring cylinder and the housing with a pin. It has a large sealing force, reliable and stable installation under high pressure, and good impact resistance. In addition, the number of grooves can be adjusted according to the medium pressure to adapt to different discharge pressures.

[0033] 3. This utility model provides an LNG discharge check valve in which the spring and the discharged medium are separated by a spring cylinder, avoiding the impact of discharge impact on the spring, increasing the service life of the check valve, and reducing the risk of check valve failure due to impurities clogging the spring. All components are made of metal materials, have good low-temperature resistance, and good compatibility with the medium.

[0034] 4. The LNG discharge check valve provided by this utility model is designed with inlet connection thread, outlet connection thread and two internal threads. The installation and disassembly are convenient, the risk of leakage is small, and the thread connection form can be changed according to the specific application, making it more applicable. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of an embodiment of an LNG discharge check valve according to this utility model;

[0036] Figure 2 This is a schematic diagram of the annular groove in an embodiment of this utility model;

[0037] Figure 3 This is a schematic diagram of the valve core structure in an embodiment of this utility model;

[0038] Figure 4 This is a schematic diagram of the structure of the spring cylinder in an embodiment of this utility model;

[0039] Figure 5 This is a schematic diagram of the pin structure in an embodiment of this utility model.

[0040] Reference numerals: 1-One-way valve body, 11-First through-hole section, 12-Second through-hole section, 13-Third through-hole section; 2-Valve core, 21-Valve core spherical section, 22-Valve core limiting section, 23-Valve core guide section; 3-Spring; 4-Spring cylinder, 41-Cylinder guide section, 42-Cylinder threaded section, 43-Cylinder pin hole section, 44-Cylinder boss; 5-Pin; 6-Inlet connection thread; 7-Outlet connection thread; 8-Annular groove. Detailed Implementation

[0041] The specific technical solutions in the embodiments of this utility model will be further described below with reference to the accompanying drawings.

[0042] Figure 1 An LNG discharge check valve provided in this embodiment of the present invention is used for reciprocating discharge of LNG cryogenic high-pressure pumps, and includes a check valve housing 1. The discharge direction is upward.

[0043] The one-way valve housing 1 is a cylindrical housing, and its inner bore includes a first through-hole section 11, a second through-hole section 12, and a third through-hole section 13 arranged coaxially from bottom to top, with the inner diameters D11, D12, and D13 of the first through-hole section 11, second through-hole section 12, and third through-hole section 13 increasing sequentially. The lower outer circumference of the one-way valve housing 1 is provided with an inlet connection thread 6, and the upper outer circumference is provided with an outlet connection thread 7, for connecting external equipment. The first through-hole section 11 is used to connect to the input end of the LNG cryogenic high-pressure pump.

[0044] refer to Figure 3, a valve core 2 is installed inside a one-way valve housing 1. The valve core 2 includes a valve core spherical section 21, a valve core limiting section 22, and a valve core guiding section 23 that are connected in sequence from bottom to top. A valve core inner hole with one end communicating with the inner hole of the one-way valve housing 1 is provided inside the valve core guiding section 23. Four valve core through holes that communicate its outer surface and the other end of the valve core inner hole are provided in the valve core limiting section 22. The maximum outer diameter D21 of the valve core spherical section 21, the maximum outer diameter D22 of the valve core limiting section 22, and the outer diameter D23 of the valve core guiding section 23 satisfy the relationship: D12 = D22 > D21 = D23 > D11, such that an upward first step surface is formed between the first through hole section 11 and the second through hole section 12, and an upward and limiting second step surface is formed between the outer surfaces of the valve core limiting section 22 and the valve core guiding section 23; the first step surface is a tapered table surface with the small end downward.

[0045] The valve core limiting section 22 includes a tapered section with the small end downward and connected to the valve core spherical section 21, and a cylindrical section coaxially connected to the large end of the tapered section and the lower end of the valve core guiding section 23 respectively; the outer peripheral surface of the tapered section is an arc concave surface; the valve core through holes are provided on the tapered section; the maximum outer diameter D22 of the valve core limiting section 22 is the outer diameter of the cylindrical section.

[0046] Reference Figure 4 , a spring cylinder 4 is installed inside the third through hole section 13. The spring cylinder 4 is provided with a three-section inner hole, and this inner hole includes a cylinder guiding section 41, a cylinder threaded section 42, and a cylinder pin hole section 43 that are coaxially connected in sequence from bottom to top; the inner diameter D41 of the cylinder guiding section 41, the inner diameter D42 of the cylinder threaded section 42, and the minimum inner diameter D43 of the cylinder pin hole section 43 satisfy the conditions: D42 < D41 and D42 < D43. The cylinder guiding section 41 is sleeved on the valve core guiding section 23, and a cylinder boss 44 extending downward into the second through hole section 12 is provided below the cylinder guiding section 41.

[0047] A spring 3 is sleeved on the outer periphery of the valve core guiding section 23. The upper end of the spring 3 abuts against the lower end surface of the cylinder guiding section 41 through the cylinder boss 44, and the lower end of the spring 3 abuts against the second step surface.

[0048] The outer diameters of the cylinder guiding section 41, the cylinder threaded section 42, and the cylinder pin hole section 43 are adapted to the inner diameter of the third through hole section 13; the cylinder boss 44 is sleeved on the upper end of the valve core guiding section 23, and the outer diameter of the cylinder boss 44 is adapted to the inner diameter of the second through hole section 12. The outer diameter D22 of the cylindrical section of the valve core limiting section 22 is adapted to the inner diameter D12 of the second through hole section 12, which is used to cooperate with the cylinder boss 44 to seal the spring 3, avoiding the direct contact between the spring 3 and the fluid medium, avoiding the influence of liquid impact, and at the same time reducing the risk of the one-way valve failure caused by the impurities in the liquid blocking the spring 3, increasing the life of the one-way valve.

[0049] Reference Figure 5A hollow pin 5 is provided inside the pin hole section 43 of the spring cylinder, and the outer circumferential surface of the pin 5 is an outer cone-shaped surface with the small end facing downwards. The inner wall of the threaded section 42 of the spring cylinder 4 is provided with internal threads; the inner wall of the pin 5 is provided with internal threads to facilitate connection to external mounting fixtures.

[0050] refer to Figure 2 The inner circumferential surface of the pressure cylinder pin hole section 43 is an inner frustoconical surface with the smaller end facing downwards. The inner frustoconical surface of the pressure cylinder pin hole section 43 is press-fitted with the outer frustoconical surface of the pin 5. The outer circumferential surface of the pressure cylinder pin hole section 43 is provided with an interlocking structure to achieve the fastening of the pressure cylinder pin hole section 43 and the third through hole section 13. The interlocking structure consists of multiple annular grooves 8 evenly distributed in parallel along its axial direction on the outer surface of the pressure cylinder pin hole section 43, the number of which is adjusted according to the medium pressure. After the inner conical surface of the pressure cylinder pin hole section 43 is pressed against the pin 5, the annular grooves 8 are squeezed and deformed, thereby achieving the installation and fit. This method is convenient for disassembly, has a low risk of leakage, can reduce the overall size, and allows the drain check valve to open and close quickly.

[0051] In this invention, the inner diameter D24 of the valve core inner hole, the inner diameter D42 of the spring cylinder thread section 42, and the inner diameter D51 of the pin 5 inner hole are all equal to the inner diameter D11 of the first through hole section 11. The one-way valve body 1, valve core 2, spring cylinder 4, spring 3, and pin 5 are all made of metal materials with good compatibility with the medium.

[0052] The installation method of this utility model is as follows:

[0053] During installation, the pin 5 is pressed tightly into the spring cylinder 4. The annular groove 8 of the spring cylinder 4 is deformed by the one-way valve body 1 due to the interference fit of the conical surface, thus completing the installation. The inner hole of the pin 5 is provided with internal threads, and the spring cylinder 4 is also provided with internal threads, which can be screwed into the screw or other tooling to assist in installation or disassembly.

[0054] When the piston pump discharges liquid, the liquid flows from bottom to top, pushing the spherical surface of the valve core 2, valve core spherical section 21, compressing the spring 3, and the one-way valve opens automatically; when the fluid flows back, it flows from top to bottom, the spherical surface of the valve core 2, valve core spherical section 21, and the valve seat (the upper conical surface of the first through hole section 11) are pressed together to seal, and the one-way valve closes.

[0055] The above description is merely an embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any equivalent structural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are included within the patent protection scope of this utility model. For those skilled in the art, it will be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this utility model. The scope of this utility model is defined by the appended claims and their equivalents.

Claims

1. An LNG drainage check valve is used for draining liquid of an LNG cryogenic high-pressure pump; It is characterized in that: It includes a check valve housing (1); The check valve housing (1) is a cylindrical housing, and its inner hole includes a first through-hole section (11), a second through-hole section (12) and a third through-hole section (13) which are coaxially arranged from bottom to top in sequence. The inner diameter D11 of the first through-hole section (11), the inner diameter D12 of the second through-hole section (12) and the inner diameter D13 of the third through-hole section (13) increase in sequence; the first through-hole section (11) is used for connecting with the input end of the LNG cryogenic high-pressure pump; A valve core (2) is installed in the check valve housing (1). The valve core (2) includes a valve core spherical section (21), a valve core limiting section (22) and a valve core guiding section (23) which are connected in sequence from bottom to top; a valve core inner hole with one end communicating with the inner hole of the check valve housing (1) is arranged in the valve core guiding section (23), and at least one valve core through-hole communicating its outer surface and the other end of the valve core inner hole is arranged in the valve core limiting section (22); The maximum outer diameter D21 of the valve core spherical section (21), the maximum outer diameter D22 of the valve core limiting section (22) and the outer diameter D23 of the valve core guiding section (23) satisfy the relationship: D12≥D22>D21>D11, and D12≥D22>D23>D11, so that an upward first step surface is formed between the first through-hole section (11) and the second through-hole section (12), and an upward and limiting second step surface is formed between the outer surfaces of the valve core limiting section (22) and the valve core guiding section (23); A spring cylinder (4) is installed in the third through-hole section (13). The inner hole of the spring cylinder (4) includes a cylinder guiding section (41), a cylinder thread section (42) and a cylinder pin hole section (43) which are connected in sequence from bottom to top; the inner diameter D41 of the cylinder guiding section (41), the inner diameter D42 of the cylinder thread section (42) and the minimum inner diameter D43 of the cylinder pin hole section (43) satisfy the condition: D42<D41 and D42<D43; the cylinder guiding section (41) is sleeved on the valve core guiding section (23); A spring (3) is sleeved on the outer periphery of the valve core guiding section (23). The upper end of the spring (3) abuts against the lower end surface of the cylinder guiding section (41), and the lower end of the spring (3) abuts against the second step surface; A hollow pin (5) is arranged in the cylinder pin hole section (43). The outer circumferential surface of the pin (5) is an outer conical table surface with the small end downward; the inner circumferential surface of the cylinder pin hole section (43) is an inner conical table surface with the small end downward; the inner conical table surface of the cylinder pin hole section (43) is in interference fit with the outer conical table surface of the pin (5), and a biting structure is arranged on the outer circumferential surface of the cylinder pin hole section (43) for realizing the fastening of the cylinder pin hole section (43) and the third through-hole section (13) in cooperation.

2. The LNG drainage check valve according to claim 1, characterized in that: The valve core limiting section (22) includes a frustum section with the small end downward and connected with the valve core spherical section (21), and a cylindrical section respectively coaxially connected with the large end of the frustum section and the lower end of the valve core guiding section (23); The outer circumferential surface of the frustum section is an arc concave surface; The valve core through-hole is located on the frustum section; The maximum outer diameter D22 of the valve core limiting section (22) is the outer diameter of the cylindrical section.

3. The LNG discharge check valve according to claim 2, characterized in that: The first step surface is a frustum-shaped surface with the smaller end facing downwards.

4. An LNG discharge check valve according to claim 3, characterized in that: The outer diameters of the pressure cylinder guide section (41), the pressure cylinder threaded section (42), and the pressure cylinder pin hole section (43) are adapted to the inner diameter D13 of the third through hole section (13); The pressure cylinder guide section (41) is provided with a pressure cylinder boss (44) extending downward into the second through hole section (12) below it. The pressure cylinder boss (44) is sleeved on the upper end of the valve core guide section (23). The outer diameter of the pressure cylinder boss (44) is adapted to the inner diameter D12 of the second through hole section (12). The upper end of the spring (3) abuts against the lower end face of the pressure cylinder guide section (41) through the pressure cylinder boss (44).

5. An LNG discharge check valve according to claim 4, characterized in that: The outer diameter D22 of the cylindrical section of the valve core limiting section (22) is adapted to the inner diameter D12 of the second through hole section (12) to achieve sealing of the spring (3) by combining with the pressure cylinder boss (44).

6. An LNG discharge check valve according to claim 5, characterized in that: The engagement structure of the pressure cylinder pin hole section (43) is at least three annular grooves (8) provided on its outer surface; the at least three annular grooves (8) are evenly distributed side by side along its axial direction.

7. An LNG discharge check valve according to claim 6, characterized in that: The inner wall of the threaded section (42) of the pressure cylinder is provided with an internal thread for cooperating with external installation fixtures; The inner wall of the pin (5) is provided with an internal thread for mating with external mounting fixtures.

8. An LNG discharge check valve according to claim 7, characterized in that: The inner diameter D24 of the valve core inner hole, the inner diameter D42 of the pressure cylinder thread section (42) and the inner diameter D51 of the pin (5) inner hole are all equal to the inner diameter D11 of the first through hole section (11).

9. An LNG discharge check valve according to claim 1, characterized in that: The lower outer periphery of the one-way valve housing (1) is provided with an inlet connection thread (6) for connecting with external equipment, and the upper outer periphery is provided with an outlet connection thread (7) for connecting with external equipment.

10. An LNG discharge check valve according to claim 1, characterized in that: The one-way valve housing (1), valve core (2), spring cylinder (4), spring (3), and pin (5) are all made of metal materials.

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