Gas shut-off valve

Abstract

The present invention provides a gas shut-off valve, comprising a valve seat, a valve body assembly, a coil assembly and a locking nut. The lower end of the valve body assembly is inserted into the valve seat from the sealing port and can move up and down to control the on-off of the gas path. The outer side of the upper end of the valve body assembly is sleeved with a coil assembly and fixed by a locking nut. The valve body assembly comprises a valve body, a valve core assembly and a pilot seat. The valve core assembly comprises a valve core, a ejector pin, a reset spring and a sealing seat. The valve core is arranged inside the valve body, and the lower end extends downward, and the end is connected to the pilot seat. The reset spring is arranged in the center hole of the valve core, the upper end is connected to the ejector pin, and the lower end is connected to the sealing seat. The upper end of the ejector pin abuts against the top of the valve body, and the sealing seat is blocked at the lower end of the center hole. The present invention improves the opening ability of the shut-off valve by improving the structure of the valve body, thereby improving the stability of the on-off of the shut-off valve.

Description

Technical Field

[0001] The invention relates to a gas cut-off valve which is applied to an air intake system of a gas engine and is used to control the on-off of a gas circuit. Background Art

[0002] The gas engine intake system uses valves to control the on and off of the gas circuit. Currently, such valves on the market mainly include PARKER shut-off valves, Metatron shut-off valves, etc. Their structures mainly include pilot seats, return springs, electromagnetic suction components, etc. The pilot seat keeps the shut-off valve in a normally closed state under the elastic force of the return spring, and the shut-off valve is opened by overcoming the elastic force of the return spring through the electromagnetic suction component.

[0003] The cut-off valve structure in the prior art has the following problems: First, in the current cut-off valve structure, there is a certain pressure difference between the inside and outside of its gas path when it is in the cut-off state, and a large electromagnetic force is required to open it directly. Secondly, the reset spring inside the cut-off valve is generally made of a spring of ordinary material and process, and its stiffness characteristics remain constant at different working temperatures. During normal operation, the electromagnetic force overcomes the reset spring force and the deadweight of the valve core to open it. However, when working in winter (temperature below -5°C), the pilot seat and the valve seat are adhered due to ice, which produces additional opening resistance, making it difficult to open the cut-off valve, so that the engine cannot start. Thirdly, in the prior art, a sealing ring is used between the pilot seat and the valve seat for sealing isolation, and the pilot seat is "sucked" by the pressure difference between the upstream and downstream of the pilot seat, thereby opening the cut-off valve; when the sealing ring fails, it is impossible to generate a pressure difference between the upstream and downstream of the pilot seat, resulting in the cut-off valve being unable to open or difficult to open. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in order to overcome the deficiencies in the prior art, the present invention provides a gas shut-off valve.

[0005] The technical solution to be adopted by the present invention to solve its technical problem is: a gas shut-off valve, comprising a valve seat, a valve body assembly, a coil assembly and a locking nut, wherein the valve seat is provided with an air inlet, an air outlet and a sealing port, the valve seat is provided with an air path connecting the air inlet and the air outlet, the lower end of the valve body assembly is inserted into the valve seat from the sealing port, and can move up and down to control the on and off of the air path, the outer side of the upper end of the valve body assembly is sleeved with the coil assembly, and the coil assembly is fixed to the valve body assembly through the locking nut at the top of the valve body assembly;

[0006] The valve body assembly includes a valve body, a valve core assembly and a pilot seat, wherein the valve core assembly includes a valve core, a ejector pin, a return spring and a sealing seat, the valve core is arranged inside the valve body, and the lower end extends downward, and the end is connected to the pilot seat; a center hole is provided inside the valve core, the return spring is arranged in the center hole, the upper end of the return spring is connected to the ejector pin, the ejector pin can slide in the center hole, and extend upward to abut against the top of the inner side of the valve body, the lower end of the return spring is connected to the sealing seat, and the sealing seat is arranged at the lower end of the center hole; an air guide hole is provided in the pilot seat, and the sealing seat can close the upper end of the air guide hole, and the lower end of the air guide hole is connected to the air outlet of the valve seat.

[0007] In the cut-off state, the coil assembly is not energized, and the elastic force generated by the reset spring blocks the pilot seat on the air path, thereby disconnecting the cut-off valve. When it needs to be opened, the coil assembly is energized, and the internal valve core assembly is lifted by electromagnetic force, thereby opening the valve. When opening, the cut-off valve is not directly opened completely, but the bottom of the sealing seat is first separated from the pilot seat, so that the air guide hole is connected to the outside to achieve air pressure pre-balance, and then the pilot seat is opened again to achieve full opening of the cut-off valve. The electromagnetic force during opening is reduced through two processes.

[0008] Furthermore, the return spring is made of a memory alloy. When the temperature drops to a certain temperature range, for example, when the temperature drops to a range of -5°C to 5°C, the stiffness of the return spring changes suddenly, and the stiffness of the return spring decreases. By improving the stiffness of the return spring to reduce resistance, the shut-off valve can be opened smoothly.

[0009] Furthermore, a first sealing surface is provided at the upper end of the sealing port, a second sealing surface is provided at the lower end, a buffer cavity is provided between the first sealing surface and the second sealing surface, and the lower end of the pilot seat is located in the buffer cavity and can move up and down in the buffer cavity.

[0010] Furthermore, the valve body includes a plunger, an isolating sleeve and a connecting seat which are sequentially connected from top to bottom, wherein the plunger and the connecting seat are magnetic conductors, and the isolating sleeve is a non-magnetic conductor. By adding the magnetic conductor, the opening capacity is increased.

[0011] Furthermore, a first external threaded portion connected to a locking nut is provided on the top of the plunger; an annular boss is provided on the middle portion of the outer side of the connecting seat, and the outer shape of the annular boss is a regular hexagonal structure, the upper end surface of the annular boss is used to support the coil assembly, and the lower end surface is used to support the valve seat to seal the sealing port; the regular hexagon is convenient for clamping the locking tool during threaded connection, and a first sealing ring groove is provided on the connecting seat below the annular boss, and a first sealing ring is provided in the first sealing ring groove, and the first sealing ring realizes the sealing of the first sealing surface; a second external threaded portion is provided on the connecting seat below the first sealing ring groove, and a threaded connection is realized with the valve seat through the second external threaded portion, thereby being fixed on the valve seat.

[0012] Furthermore, a through hole is provided inside the connecting seat, and the through hole includes a first guide portion and a second guide portion, wherein the first guide portion is used for guiding the valve core, and the second guide portion is used for guiding the pilot seat, and the inner diameter of the first guide portion is smaller than the inner diameter of the second guide portion, and a conical surface transition is adopted between the first guide portion and the second guide portion. The conical surface can realize the transition between different apertures on the one hand, and can limit the stroke of the pilot seat on the other hand. A conical third sealing surface is provided at the lower end of the second guide portion, and a fourth sealing surface matching the third sealing surface is provided on the pilot seat. When the cut-off valve is opened, the valve core assembly drives the pilot seat to move upward, so that the fourth sealing surface fits and seals with the third sealing surface.

[0013] Furthermore, the center hole of the valve core includes a pin mounting portion, a spring mounting portion and a sealing seat mounting groove which are sequentially connected from top to bottom, and the inner diameter of the pin mounting portion is smaller than the inner diameter of the spring mounting portion, so as to prevent the return spring from directly entering the pin mounting portion, thereby ensuring that the return spring is always in a compressed state, generating an upward elastic force, so that the pin always remains in contact with the plunger; a conical surface transition is adopted at the connection, and the inner diameter of the sealing seat mounting groove is larger than the inner diameter of the spring mounting portion, so that the sealing seat is confined in the sealing seat mounting groove and cannot move over a large range along the axis.

[0014] Furthermore, a valve core head is provided at the lower end of the valve core, and an annular clamping groove is provided on the outer side of the valve core head. The clamping groove matches the C-shaped clamping platform of the pilot seat, and during assembly, the C-shaped clamping platform is embedded in the clamping groove, thereby limiting the axial movement between the pilot seat and the valve core.

[0015] Furthermore, the pilot seat is a stepped structure with a small outer diameter at the top and a large outer diameter at the bottom, and a C-shaped clamping platform with a lateral opening is provided on the top of the pilot seat, and the C-shaped clamping platform is clamped with the clamping groove on the valve core head. When connected, the C-shaped clamping platform of the pilot seat is radially clamped into the clamping groove on the valve core head; and the C-shaped clamping platform can move up and down in the clamping groove, and the width of the clamping groove is greater than the thickness of the C-shaped clamping platform, so as to realize up and down movement, open the air inlet on the side, and allow external air flow to enter the valve to balance the air pressure; a connecting cavity is provided in the pilot seat below the C-shaped clamping platform, and an air inlet is provided on the side wall of the connecting cavity, and an air guide hole is axially provided inside the pilot seat, the upper end of the air guide hole is connected with the connecting cavity, and the lower end of the air guide hole is connected with the air inlet of the valve seat, and a second sealing ring groove is provided on the outer side of the lower end of the pilot seat, and a second sealing ring is provided in the second sealing ring groove, and the second sealing ring is used to seal the second sealing surface, and a fourth sealing surface matching the third sealing surface is provided on the pilot seat above the second sealing ring.

[0016] Furthermore, the coil assembly includes a shell, a frame and a coil. A through hole is provided in the middle of the frame for connecting to the valve seat. The coil is wound on the frame and sealed on the outside by the shell. The shell is provided with a wiring port for electrically connecting to the coil.

[0017] The gas shut-off valve of the present invention is in a closed state under the action of the reset spring force when no electricity is supplied, and is a normally closed shut-off valve. When the coil is energized, the valve core assembly overcomes the reset spring and moves upward under the action of the electromagnetic force, and at the same time, the valve core assembly and the pilot seat are separated, and the upstream gas reaches the downstream through the hole in the middle of the pilot seat, so that the pressure difference between the upstream and downstream of the pilot seat is reduced, and the valve core assembly drives the pilot seat to move upward through the mechanical mechanism between them until it is fully opened.

[0018] The beneficial effect of the present invention is that the gas shut-off valve provided by the present invention improves the structure of the valve body to improve the opening ability of the shut-off valve, thereby improving the on-off stability of the shut-off valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] Figure 1 It is a schematic diagram of the explosion structure of the gas shut-off valve of the present invention.

[0021] Figure 2 It is a schematic diagram of the assembly structure of the gas shut-off valve of the present invention.

[0022] Figure 3 It is a three-dimensional structural diagram of the valve seat.

[0023] Figure 4 It is a three-dimensional structural diagram of the valve seat.

[0024] Figure 5 It is a schematic diagram of the cross-sectional structure of the valve seat.

[0025] Figure 6 It is a schematic diagram of the exploded structure of the valve body assembly.

[0026] Figure 7 It is a schematic diagram of the cross-sectional structure of the valve body.

[0027] Figure 8 It is a schematic diagram of the exploded structure of the valve core assembly.

[0028] Fig. 9 It is a schematic diagram of the cross-sectional structure of the valve core.

[0029] Fig.10 It is a three-dimensional structural diagram of the pilot seat.

[0030] Fig.11 It is a schematic diagram of the cross-sectional structure of the valve body assembly from the cut-off state to the open state.

[0031] Fig.12 It is a schematic diagram of the cross-sectional structure of the gas shut-off valve of the present invention (in the shut-off state).

[0032] Fig.13 It is a schematic diagram of the cross-sectional structure of the gas shut-off valve of the present invention (open state).

[0033] In the figure: 1. valve seat, 1.1. air inlet, 1.2. sealing port, 1.3. air outlet, 1.4. buffer chamber, 1.5. first sealing surface, 1.6. second sealing surface, 2. valve body assembly, 2.1. valve body, 2.11. plunger, 2.12. isolation sleeve, 2.13. connecting seat, 2.14. first external threaded portion, 2.15. annular boss, 2.16. first sealing ring groove, 2.17. second external threaded portion, 2.18. third sealing surface, 2.19. first guide portion, 2.20. second guide portion, 2.2. valve core assembly, 2.21 , valve core, 2.211, ejector pin mounting portion, 2.212, spring mounting portion, 2.213, sealing seat mounting groove, 2.214, valve core head, 2.215, slot, 2.22, ejector pin, 2.23, return spring, 2.24, sealing seat, 2.3, pilot seat, 2.31, air inlet, 2.32, air guide hole, 2.33, fourth sealing surface, 2.34, second sealing ring groove, 2.35, C-shaped fixture, 2.36, connecting cavity, 3, coil assembly, 3.1, wiring port, 4, locking nut, 5, first sealing ring, 6, second sealing ring. DETAILED DESCRIPTION

[0034] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner only, and therefore only show the components related to the present invention, and directions and references (e.g., up, down, left, right, etc.) may only be used to help describe the features in the drawings. Therefore, the following specific embodiments are not to be taken in a limiting sense, and the scope of the subject matter claimed is limited only by the attached claims and their equivalents.

[0035] like Figure 1 and Figure 2 As shown, a gas shut-off valve of the present invention comprises a valve seat 1, a valve body assembly 2, a coil assembly 3 and a locking nut 4. The lower end of the valve body assembly 2 is inserted into the valve seat 1 from the sealing port 1.2, and can move up and down to control the on-off of the gas path. The outer side of the upper end of the valve body assembly 2 is sleeved with the coil assembly 3, and the coil assembly 3 is fixed to the valve body assembly 2 through the locking nut 4 at the top of the valve body assembly 2. The coil assembly 3 comprises a shell, a skeleton and a coil. A through hole is provided in the middle of the skeleton for connecting with the valve seat 1. The coil is wound on the skeleton and sealed on the outside by the shell. The shell is provided with a wiring port 3.1 for electrically connecting with the coil.

[0036] like Figure 3-Figure 5 As shown, the valve seat 1 is provided with an air inlet 1.1, an air outlet 1.3 and a sealing port 1.2, and an air path connecting the air inlet 1.1 and the air outlet 1.3 is provided inside the valve seat 1. The sealing port 1.2 is provided with a first sealing surface 1.5 at the upper end and a second sealing surface 1.6 at the lower end, and a buffer cavity 1.4 is provided between the first sealing surface 1.5 and the second sealing surface 1.6.

[0037] like Figure 6 As shown, the valve body assembly 2 includes a valve body 2.1, a valve core assembly 2.2 and a pilot seat 2.3. The valve core assembly 2.2 is arranged inside the valve body 2.1, and the lower end is connected to the pilot seat 2.3. The lower end of the pilot seat 2.3 is located in the buffer cavity 1.4 and can move up and down in the buffer cavity 1.4 to open and close the pressure pre-balance.

[0038] like Figure 7As shown, the valve body 2.1 includes a plunger 2.11, a spacer sleeve 2.12 and a connection seat 2.13 connected in sequence from top to bottom, wherein the plunger 2.11 and the connection seat 2.13 are magnetic conductors, and the spacer sleeve 2.12 is a non-magnetic conductor. By adding the magnetic conductor, the opening capacity is increased. The top of the plunger 2.11 is provided with a first external threaded portion 2.14 connected to the locking nut 4, the upper end of the plunger 2.11 passes through the through hole of the coil assembly 3 skeleton, and the first external threaded portion 2.14 at the end is threadedly connected to the locking nut 4 to lock the coil assembly 3 on the valve seat 1. An annular boss 2.15 is provided in the middle part of the outer side of the connecting seat 2.13, and the shape of the annular boss 2.15 is a regular hexagonal structure. The upper end face of the annular boss 2.15 is used to support the coil assembly 3, and the lower end face is used to support on the valve seat 1 to seal the sealing port 1.2; the regular hexagon is convenient for clamping the locking tool during threaded connection; a first sealing ring groove 2.16 is provided on the connecting seat 2.13 below the annular boss 2.15, and a first sealing ring 5 is provided in the first sealing ring groove 2.16. The first sealing ring 5 realizes the sealing of the first sealing surface 1.5, that is, realizes the sealing between the valve seat 1 and the valve body 2.1; a second external threaded portion 2.17 is provided on the connecting seat 2.13 below the first sealing ring groove 2.16, and a threaded connection is realized with the valve seat 1 through the second external threaded portion 2.17, so that the valve body 2.1 is fixed on the valve seat 1. A through hole is provided inside the connecting seat 2.13, and the through hole includes a first guide portion 2.19 and a second guide portion 2.20. The first guide portion 2.19 is used for guiding the valve core, and the second guide portion 2.20 is used for guiding the pilot seat 2.3. The inner diameter of the first guide portion 2.19 is smaller than the inner diameter of the second guide portion 2.20, and a conical surface transition is adopted between the first guide portion 2.19 and the second guide portion 2.20. The conical surface can realize the transition between different apertures on the one hand, and can limit the stroke of the pilot seat 2.3 on the other hand. A conical third sealing surface 2.18 is provided at the lower end of the second guide portion 2.20, and a fourth sealing surface 2.33 cooperating with the third sealing surface 2.18 is provided on the pilot seat 2.3. When the cut-off valve is opened, the valve core assembly 2.2 drives the pilot seat 2.3 to move upward, so that the fourth sealing surface 2.33 fits and seals with the third sealing surface 2.18.

[0039] like Figure 8As shown, the valve core assembly 2.2 includes a valve core 2.21, a pin 2.22, a return spring 2.23 and a sealing seat 2.24. The valve core 2.21 is arranged inside the valve body 2.1, and the lower end extends downward, and the end is connected to the pilot seat 2.3; the valve core 2.21 is provided with a center hole inside, and the return spring 2.23 is arranged in the center hole. The upper end of the return spring 2.23 is connected to the pin 2.22, and the pin 2.22 can slide in the center hole and extend upward to abut against the top of the inner side of the valve body 2.1. The lower end of the return spring 2.23 is connected to the sealing seat 2.24, and the sealing seat 2.24 is blocked at the lower end of the center hole. The return spring 2.23 is made of memory alloy, and the relationship between the stiffness of the return spring 2.23 and the temperature is: the stiffness of the spring becomes lower (the length becomes shorter) at low temperature, and the stiffness of the spring becomes higher (the length becomes longer) at high temperature. By improving the spring to reduce resistance, the valve can be opened smoothly. The temperature mutation range of the spring can be designed according to the requirements. In this embodiment, when the temperature drops to the range of -5℃~5℃, the stiffness of the reset spring 2.23 suddenly decreases. By adopting this design, in winter (below -5℃), when the cut-off valve is closed at the normal operating temperature, if it is not started for a long time, when it is started next time, the stiffness of the reset spring 2.23 becomes smaller because the ambient temperature is lower than the phase change temperature of the reset spring 2.23, and the spring force overcome by the solenoid valve when it is started is also reduced, thereby improving the opening ability of the cut-off valve.

[0040] like Fig. 9 As shown, the center hole of the valve core 2.21 includes a pin mounting portion 2.211, a spring mounting portion 2.212 and a sealing seat mounting groove 2.213 which are sequentially connected from top to bottom, the pin 2.22 is arranged in the pin mounting portion 2.211, the return spring 2.23 is arranged in the spring mounting portion 2.212, and the sealing seat 2.24 is arranged in the sealing seat mounting groove 2.213; the inner diameter of the pin mounting portion 2.211 is smaller than the inner diameter of the spring mounting portion 2.212, so as to prevent the return spring 2.23 from directly entering the pin mounting portion 2.211, and ensure that the return spring 2.23 is always in a compressed state, generating an upward elastic force, so that the pin 2.22 always keeps abutting against the plunger 2.11; the connection adopts a conical surface transition, and the inner diameter of the sealing seat mounting groove 2.213 is larger than the inner diameter of the spring mounting portion 2.212, so that the sealing seat 2.24 is restricted in the sealing seat mounting groove 2.213 and cannot move along the axis in a large range. The lower end of the valve core 2.21 is provided with a valve core head 2.214, and the outer side of the valve core head 2.214 is provided with an annular clamping groove 2.215. The clamping groove 2.215 matches the C-shaped clamping platform 2.35 of the pilot seat 2.3. During assembly, the C-shaped clamping platform 2.35 is embedded in the clamping groove 2.215, thereby limiting the axial movement between the pilot seat 2.3 and the valve core 2.21.

[0041] like Fig.10As shown, the pilot seat 2.3 is a stepped structure with a small outer diameter at the upper part and a large outer diameter at the lower part. A C-shaped clamping platform 2.35 with a lateral opening is provided on the top of the pilot seat 2.3. The C-shaped clamping platform 2.35 is clamped with the clamping groove 2.215 on the valve core head 2.214. When connected, the C-shaped clamping platform 2.35 of the pilot seat 2.3 is radially clamped into the clamping groove 2.215 on the valve core head 2.214; and the C-shaped clamping platform 2.35 can move up and down in the clamping groove 2.215, and the width of the clamping groove 2.215 is greater than the thickness of the C-shaped clamping platform 2.35, so as to realize the up and down movement, open the side air inlet 2.31, balance the air pressure inside and outside the valve, reduce the resistance to opening, and facilitate the valve core assembly 2.2 to move upward and open; the C A connecting cavity 2.36 is provided in the pilot seat 2.3 below the shaped card table 2.35, and an air inlet 2.31 is provided on the side wall of the connecting cavity 2.36. An air guide hole 2.32 is axially provided inside the pilot seat 2.3, and the upper end of the air guide hole 2.32 is communicated with the connecting cavity 2.36, and the lower end of the air guide hole 2.32 is communicated with the air inlet 1.1 of the valve seat 1. A second sealing ring groove 2.34 is provided on the outer side of the lower end of the pilot seat 2.3, and a second sealing ring 6 is provided in the second sealing ring groove 2.34. The second sealing ring 6 is used to seal the second sealing surface 1.6, and a fourth sealing surface 2.33 matching the third sealing surface 2.18 is provided on the pilot seat 2.3 above the second sealing ring 6.

[0042] Working principle:

[0043] like Fig.11 The left picture and Fig.12 The figure shows a schematic diagram of the cut-off valve in the cut-off state. In the cut-off state, the coil is not energized, the upper end of the ejector pin 2.22 is against the bottom surface of the plunger 2.11, and the return spring 2.23 at the lower end generates a downward elastic force to press the valve core 2.21 downward through the sealing seat 2.24. The valve core 2.21 pushes the pilot seat 2.3 to move from top to bottom in the buffer chamber 1.4. At this time, the third sealing surface 2.18 and the fourth sealing surface 2.33 are separated, and the second sealing ring 6 at the end of the pilot seat 2.3 is pressed tightly against the second sealing surface 1.6 to block the air path, thereby realizing the disconnection of the cut-off valve.

[0044] When the shut-off valve needs to be opened, Fig.11 The right picture and Fig.13 The diagram shows the shut-off valve in the open state. Fig.11 The dotted arrow in the right figure shows the direction of airflow when the pressure is balanced. Fig.13 The solid arrow in the middle shows the direction of air flow when the shut-off valve is fully opened.

[0045] First, the coil is energized to generate a magnetic field, and the valve body 2.1 generates an upward suction force on the valve core 2.21. At the beginning, due to the large pressure difference between the inside and outside of the cut-off valve, a relatively large force needs to be overcome to lift the pilot seat 2.3. Therefore, if Fig.11 As shown in the right figure, under the action of magnetic force, only the valve core 2.21 moves upward, while the pilot seat 2.3 does not move temporarily. When the valve core 2.21 drives the sealing seat 2.24 to move upward for a distance, the external airflow can enter the connecting cavity 2.36 from the air inlet 2.31 on the side of the pilot seat 2.3, thereby introducing the airflow into the air outlet 1.3 of the valve seat 1 through the air guide hole 2.32 in the middle of the pilot seat 2.3, thereby reducing the air pressure difference on both sides of the pilot seat 2.3, balancing the pressure inside and outside the cut-off valve, reducing the internal and external pressure difference, and performing air pressure pre-balancing. During air pressure pre-balancing, since the area of ​​the air guide hole 2.32 is relatively small, the pressure generated on the sealing seat 2.24 is relatively small, and the force to lift the sealing seat 2.24 is relatively small, so it is relatively easy to achieve. At this time, the valve core 2.21 continues to move upward. Since there is no pressure difference or the pressure difference is small on both sides of the pilot seat 2.3, the pilot seat 2.3 can be driven to move upward synchronously, so that the air inlet 1.1 of the valve seat 1 is directly connected with the air outlet 1.3, so that the cut-off valve is in a fully open state. Fig.13 As shown, at this time, the third sealing surface 2.18 and the fourth sealing surface 2.33 are tightly fitted, and the second sealing ring 6 is lifted upward along with the pilot seat 2.3 and separated from the second sealing surface 1.6.

[0046] In winter, when the temperature is relatively low and the ice weather is Fig.12 In the cut-off state shown, the elongation of the reset spring 2.23 is relatively large. If ice forms when opening, in addition to overcoming the elastic force of the reset spring 2.23, it is also necessary to overcome the bonding force caused by ice, thereby affecting the opening of the cut-off valve. In this embodiment, the reset spring 2.23 is made of memory alloy, and its stiffness will decrease when the temperature decreases, that is, the elongation will decrease, so that the elastic force of the reset spring 2.23 will also be relatively reduced, so that the elastic force on the reset spring 2.23 is reduced to compensate for the additional resistance caused by ice, thereby improving the winter opening ability of the cut-off valve.

[0047] In addition, in this embodiment, the structure of the valve body 2.1 is improved by adding a magnetic conductive material portion of the valve body 2.1, reducing the air gap of the magnetic circuit and increasing the electromagnetic force. Under the same voltage, the magnetic force is stronger, which further ensures the ability of the shut-off valve to open in winter.

[0048] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the scope of the present invention through the above description. The technical scope of this invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A gas shut-off valve, characterized in that: It includes a valve seat, a valve body assembly, a coil assembly and a locking nut, wherein the valve seat is provided with an air inlet, an air outlet and a sealing port, the valve seat is provided with an air path connecting the air inlet and the air outlet, the lower end of the valve body assembly is inserted into the valve seat from the sealing port, and can move up and down to control the on and off of the air path, the outer side of the upper end of the valve body assembly is sleeved with the coil assembly, and the coil assembly is fixed to the valve body assembly through the locking nut at the top of the valve body assembly; The valve body assembly comprises a valve body, a valve core assembly and a pilot seat, wherein the valve core assembly comprises a valve core, an ejector pin, a return spring and a sealing seat, the valve core is arranged inside the valve body, and the lower end extends downward, and the end is connected to the pilot seat; a center hole is arranged inside the valve core, the return spring is arranged in the center hole, the upper end of the return spring is connected to the ejector pin, the ejector pin can slide in the center hole, and extends upward to abut against the top of the inner side of the valve body, the lower end of the return spring is connected to the sealing seat, and the sealing seat is arranged at the lower end of the center hole; an air guide hole is arranged in the pilot seat, and the sealing seat can close the upper end of the air guide hole, and the lower end of the air guide hole is communicated with the air outlet of the valve seat; The return spring is made of memory alloy, and when the temperature drops to a range of -5°C to 5°C, the stiffness of the return spring decreases; The sealing port is provided with a first sealing surface at the upper end and a second sealing surface at the lower end, a buffer cavity is provided between the first sealing surface and the second sealing surface, and the lower end of the pilot seat is located in the buffer cavity and can move up and down in the buffer cavity; A C-shaped clamping platform with a side opening is provided on the top of the pilot seat, and the C-shaped clamping platform is clamped with the clamping groove on the valve core head, and the C-shaped clamping platform can move up and down in the clamping groove; a connecting cavity is provided in the pilot seat below the C-shaped clamping platform, and an air inlet is provided on the side wall of the connecting cavity, and an air guide hole is axially provided inside the pilot seat, the upper end of the air guide hole is connected with the connecting cavity, and the lower end of the air guide hole is connected with the air inlet of the valve seat, a second sealing ring groove is provided on the outer side of the lower end of the pilot seat, a second sealing ring is provided in the second sealing ring groove, and the second sealing ring is used to seal the second sealing surface, and a fourth sealing surface matching the third sealing surface is provided on the pilot seat above the second sealing ring.

2. The gas shut-off valve according to claim 1, characterized in that: The valve body comprises a plunger, an isolating sleeve and a connecting seat which are sequentially connected from top to bottom, wherein the plunger and the connecting seat are magnetic conductors, and the isolating sleeve is a non-magnetic conductor.

3. The gas shut-off valve according to claim 2, characterized in that: A first external threaded portion connected to a locking nut is provided on the top of the plunger; an annular boss is provided in the middle portion of the outer side of the connecting seat, and the shape of the annular boss is a regular hexagonal structure; a first sealing ring groove is provided on the connecting seat below the annular boss, a first sealing ring is provided in the first sealing ring groove, and a second external threaded portion is provided on the connecting seat below the first sealing ring groove, and a threaded connection is achieved with the valve seat through the second external threaded portion.

4. The gas shut-off valve according to claim 2, characterized in that: A through hole is provided inside the connecting seat, and the through hole includes a first guide portion and a second guide portion. The inner diameter of the first guide portion is smaller than the inner diameter of the second guide portion, and a conical surface transition is adopted between the first guide portion and the second guide portion; a conical third sealing surface is provided at the lower end of the second guide portion, and a fourth sealing surface matching the third sealing surface is provided on the pilot seat.

5. The gas shut-off valve according to claim 1, characterized in that: The central hole of the valve core includes a pin mounting portion, a spring mounting portion and a sealing seat mounting groove which are sequentially connected from top to bottom. The inner diameter of the pin mounting portion is smaller than the inner diameter of the spring mounting portion. A conical surface transition is adopted at the connection. The inner diameter of the sealing seat mounting groove is larger than the inner diameter of the spring mounting portion.

6. The gas shut-off valve according to claim 1, characterized in that: A valve core head is arranged at the lower end of the valve core, and an annular clamping groove is arranged on the outer side of the valve core head.

7. The gas shut-off valve according to claim 1, characterized in that: The coil assembly includes a shell, a frame and a coil. A through hole is provided in the middle of the frame for connecting with the valve seat. The coil is wound on the frame and sealed on the outside by the shell. The shell is provided with a wiring port for electrically connecting with the coil.

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