CN219472870U - Direct-acting electromagnetic valve for ultralow-temperature medium - Google Patents

Abstract

The utility model provides a direct-acting electromagnetic valve for ultralow-temperature medium, which comprises a valve body, an extension connecting pipe and a valve rod assembly, wherein a valve cavity, a medium inlet and a medium outlet which are communicated with the valve cavity are arranged on the valve body; the lower end of the lengthened connecting pipe is in threaded connection with the valve cavity, the upper end of the lengthened connecting pipe is in threaded connection with the magnetic isolation pipe assembly, and a medium runner communicated with the valve cavity is arranged in the lengthened connecting pipe; the valve rod assembly comprises a movable iron core, a valve port sealing assembly and a connecting rod, wherein the movable iron core is slidably arranged in the magnetism isolating pipe assembly, the valve port sealing assembly is arranged in the valve cavity and used for opening and closing the valve port, the connecting rod is arranged in the medium flow passage in a penetrating mode, the upper end of the connecting rod is movably connected with the movable iron core, and the lower end of the connecting rod is connected with the valve port sealing assembly; the utility model provides a direct-acting electromagnetic valve for ultralow-temperature medium, which overcomes the defect that the existing electromagnetic valve is not applicable to ultralow-temperature medium.

Description

Direct-acting electromagnetic valve for ultralow-temperature medium

Technical Field

The utility model relates to the field of electromagnetic valves, in particular to a direct-acting electromagnetic valve for ultralow-temperature medium.

Background

Electromagnetic valves are the most widely used and important actuators and control elements in pipeline fluid delivery systems, and are indispensable equipment in the control system. The control mode of the electromagnetic valve control part can be divided into a direct-acting type and a pilot type according to the control mode of the electromagnetic valve control part on the main valve, and the reversing mode of the main valve core is directly pushed or dragged by the electromagnet movable iron core and is called as a direct-acting type; the direct-acting electromagnetic valve is directly controlled by utilizing electromagnetic effect, so that the direct-acting electromagnetic valve has the advantages of high response speed, simple structure, no minimum starting pressure limit, strong pollution resistance and interference resistance of the valve port, good repeatability, stable and reliable action, small volume and light weight.

In pipeline fluid delivery systems, it is often desirable to deliver ultra-low temperature media such as liquid nitrogen, liquid ammonia, liquid oxygen, and the like; when the ultralow-temperature medium flows into the electromagnetic valve cavity from the medium inlet, the ultralow-temperature medium can quickly influence the actuating mechanism to reduce the current of the actuating mechanism, and the electromagnetic force is weakened, so that the electromagnetic valve is easy to fail; the ultra-low temperature medium also provides higher requirements on the instantaneous opening speed and sealing performance of the electromagnetic valve, the existing electromagnetic valve is compact in structure, the valve core is short in stroke, the instantaneous opening speed is low, the valve is unreliable, a high-power coil is needed, and extra cost is increased; moreover, the sealing surface of the valve core cannot be automatically adjusted for sealing, so that the sealing performance of the valve core and the valve guide port is poor, and leakage is easy to cause; in addition, the existing solenoid valve coil assembly lacks a sealing structure, and condensed water generated outside can possibly enter the coil when ultra-low temperature media are conveyed, so that the solenoid valve is damaged, and the service life is influenced.

Disclosure of Invention

First, the technical problem to be solved

The utility model aims to solve the problem of providing a direct-acting electromagnetic valve for ultralow-temperature medium, so as to overcome the defect that the conventional electromagnetic valve is not suitable for transportation of the ultralow-temperature medium.

(II) technical scheme

In order to solve the technical problem, the utility model provides a direct-acting electromagnetic valve for ultralow-temperature medium, comprising:

the valve body is provided with a valve cavity, a medium inlet and a medium outlet which are communicated with the valve cavity, and the bottom of the valve cavity is provided with a pilot valve opening which is used for communicating with the medium outlet;

the lower end of the lengthened connecting pipe is in threaded connection with the valve cavity, the upper end of the lengthened connecting pipe is in threaded connection with the magnetic isolation pipe assembly, and a medium flow passage communicated with the valve cavity is arranged in the lengthened connecting pipe;

the valve rod assembly comprises a movable iron core, a valve port sealing assembly and a connecting rod, wherein the movable iron core is slidably arranged in the magnetic isolation pipe assembly, the valve port sealing assembly is arranged in the valve cavity and used for opening and closing the valve port, the connecting rod is arranged in the medium flow passage in a penetrating mode, the upper end of the connecting rod is movably connected with the movable iron core, and the lower end of the connecting rod is connected with the valve port sealing assembly.

Further, the valve port sealing assembly comprises a sealing seat fixedly connected with the lower end of the connecting rod, a valve port sealing piece is arranged at the lower end of the sealing seat, and a conical sealing part which is matched and sealed with the valve guide port is arranged at the lower end of the valve port sealing piece; when the valve is closed, the sealing seat can swing under the drive of the connecting rod, so that the conical sealing part and the pilot valve opening can be automatically adjusted to reach the optimal sealing position.

Further, the outside of the sealing seat is slidably sleeved with a compression spring seat, and the inner wall of the lengthened connecting pipe is provided with a limiting boss for limiting the compression spring seat; the lower extreme of seal holder is provided with the pressure spring flange, the pressure spring seat with support between the pressure spring flange has put the pressure spring, the pressure spring makes all the time the valve port sealing member has the trend towards the pilot valve mouth motion. The pressure spring seat is provided with a diversion hole, and the medium runner is communicated with the valve cavity through the diversion hole; in a closed state, the pressure of the medium flow passage is larger than the pressure of the valve cavity, so that the valve port sealing piece tightly closes the pilot valve port.

Further, a movable cavity is arranged at the lower end of the movable iron core, a limit sleeve is fixed at the upper end of the connecting rod, and the limit sleeve is loosely arranged in the movable cavity so that the connecting rod can swing and slide up and down; a positioning sleeve is sleeved on the connecting rod, and the positioning sleeve is fixed with the movable iron core to prevent the limiting sleeve from falling out of the movable cavity; in a closed state, the movable iron core is abutted against the limiting sleeve, and the limiting sleeve and the positioning sleeve are arranged at intervals; when the valve is opened, the movable iron core moves upwards, and after the positioning sleeve abuts against the limiting sleeve, the positioning sleeve instantly drives the connecting rod to move upwards, so that the valve port sealing assembly opens the pilot valve port.

Further, the sealing surface angle of the conical sealing part is 60 degrees, the valve guide port is conical, and the sealing surface angle of the valve guide port is 90 degrees.

Further, a valve port insert is fixedly arranged at the bottom of the valve cavity in an interference fit mode, and the pilot valve port is arranged on the valve port insert.

Further, a first sealing ring is arranged between the upper end of the lengthened connecting pipe and the magnetic isolation pipe assembly, and a second sealing ring is arranged between the lower end of the lengthened connecting pipe and the valve body.

Further, an electromagnetic coil assembly is arranged on the outer side of the magnetic isolation tube assembly, and the electromagnetic coil assembly is fixed with the magnetic isolation tube assembly through a flat gasket and a fixing nut; the electromagnetic coil assembly is characterized in that a lower sealing gasket is arranged between the magnetic isolation tube assembly and the electromagnetic coil assembly, an upper sealing gasket is arranged between the flat gasket and the magnetic isolation tube assembly, and an O-shaped ring is arranged between the fixing nut and the flat gasket.

Further, an upper mounting groove is formed in the upper end of the sealing seat, and the end part of the connecting rod is arranged in the upper mounting groove and is fixed through a first fixing pin; the lower end of the sealing seat is provided with a lower mounting groove, and the end part of the valve port sealing piece is arranged in the lower mounting groove and is fixed through a second fixing pin.

(III) beneficial effects

Compared with the prior art, the electromagnetic valve for the ultralow-temperature medium has the following advantages:

1) The lengthened connecting pipe is additionally arranged at the middle section of the electromagnetic valve, so that the surface area of the ultralow-temperature medium in contact with metal is increased under the action of the medium flow channel and the outer wall of the medium flow channel, the medium gasification speed is increased, the influence on the coil is greatly reduced, and the coil can be kept to operate efficiently; secondly, only a connecting rod is arranged in the lengthened connecting pipe, the current situation that the more compact and better the structure of the conventional electromagnetic valve is broken, the space in the inner cavity of the lengthened connecting pipe is remained larger, the convection of ultralow-temperature medium and air is facilitated, the temperature of the medium is increased, and the influence of the medium on a coil is weakened; in addition, the lengthened connecting pipe structure is convenient for the installation and the use of the electromagnetic valve in the low-temperature medium switch control pipeline and the connection of a coil power line;

2) The connecting rod adopts a pendulum clock type design and a conical sealing part, when the movable iron core moves up and down, under the condition that the absolute center movement cannot be ensured, the pendulum clock type design can enable the valve port sealing element to automatically swing and adjust to an optimal sealing position after entering the valve guide port, so that the sealing reliability of the electromagnetic valve is ensured, and leakage is avoided;

3) The design of the small drift diameter and the ultra-large stroke enables the electromagnetic valve to be opened by the acceleration of the movable iron core; when the valve is opened, the movable iron core moves upwards to obtain a certain speed, and then the valve port sealing element is instantaneously driven to separate from the valve guide port, so that the instantaneous speed of opening is increased, the reaction is quicker, and the opening is more reliable; the electromagnetic force required by the operation and suction of the movable iron core and the fixed iron core is greatly reduced, the power of a coil required by the operation of the electromagnetic valve is reduced, the power of the coil is reduced, and the cost of the coil can be reduced;

4) The coil adopts three waterproof seals, adds the lower sealing member in coil module bottom, adds the upper sealing member above, and fixation nut department adds O type circle, makes the comdenstion water unable entering coil inside, guarantees that the coil can effectual long-time operation.

Drawings

FIG. 1 is a schematic diagram of a direct-acting solenoid valve for ultra-low temperature media according to the present utility model;

FIG. 2 is a schematic view of a direct-acting solenoid valve body for ultra-low temperature media according to the present utility model;

FIG. 3 is a schematic view of a structure of a solenoid valve extension connection pipe for ultra-low temperature medium according to the present utility model;

FIG. 4 is a schematic view of a direct-acting solenoid valve stem assembly for ultra-low temperature media according to the present utility model;

FIG. 5 is a schematic diagram of a structure of a movable iron core and a connecting rod of a direct-acting electromagnetic valve for ultra-low temperature medium in the utility model;

FIG. 6 is a schematic view of a direct acting solenoid valve port seal assembly for ultra low temperature media according to the present utility model;

FIG. 7 is a schematic view of the structure of the electromagnetic valve cone-shaped sealing part for ultra-low temperature medium during processing according to the present utility model;

FIG. 8 is a schematic view of a direct acting solenoid valve port seal for ultra low temperature media in sealing engagement with a pilot valve port in accordance with the present utility model;

FIG. 9 is a schematic diagram of a direct-acting solenoid valve magnetic isolation tube assembly for ultra-low temperature media and solenoid assembly connection according to the present utility model;

FIG. 10 is a schematic diagram of the opening stroke of the movable iron core of the electromagnetic valve for ultra-low temperature medium in direct-acting mode;

FIG. 11 is a schematic diagram of a direct-acting solenoid valve for ultra-low temperature medium according to the present utility model after opening;

the corresponding component names for each reference number in the figures are: 1. a valve body; 101. a valve cavity; 102. a medium inlet; 103. a medium outlet; 104. a valve guide port; 105. a valve port insert; 2. lengthening the connecting pipe; 201. a media flow path; 202. a limit boss; 3. a magnetic isolation tube assembly; 4. a valve stem assembly; 41. a movable iron core; 42. a valve port seal assembly; 43. a connecting rod; 411. a movable cavity; 412. a limit sleeve; 413. a positioning sleeve; 421. a sealing seat; 422. a valve port seal; 423. a pressure spring seat; 424. a pressure spring; 425. a first fixing pin; 426. a second fixing pin; 4211. a compression spring flange; 4221. a tapered seal portion; 4231. a deflector aperture; 501. a first seal ring; 502. a second seal ring; 6. an electromagnetic coil assembly; 601. a flat gasket; 602. a fixing nut; 603. a lower gasket; 604. an upper gasket; 605. an O-ring; y, machining equipment clamps;

l1, total stroke of the movable iron core; l2, initial travel of the movable iron core; l, the actual opening of the electromagnetic valve.

Detailed Description

The following describes in further detail the embodiments of the present utility model with reference to the drawings and examples. The following examples are illustrative of the utility model and are not intended to limit the scope of the utility model.

Referring to fig. 1 to 11, the present utility model provides a direct acting solenoid valve for ultra-low temperature medium, comprising a valve body 1, an elongated connecting pipe 2, a solenoid valve assembly 3 and a valve stem assembly 4.

Referring to fig. 1 and 2, a valve cavity 101, a medium inlet 102 and a medium outlet 103 which are respectively communicated with the valve cavity 101 are arranged in the middle of the upper end of the valve body 1, a pilot valve port 104 for communicating the medium outlet 103 is arranged at the bottom of the valve cavity 101, and the electromagnetic valve is opened and closed by switching the pilot valve port 104. The bottom of the valve cavity 101 is fixedly provided with a valve port insert 105 in an interference fit mode, and a pilot valve port 104 is arranged on the valve port insert 105. The structure adopts an interference fit processing mode, ensures that the valve port insert and the valve body are sealed firmly and achieve zero leakage. When the valve port insert 105 is assembled, because the interference fit is difficult to realize absolute concentricity, the valve port insert can be placed in a liquid nitrogen (-209.86 ℃) container for a period of time, the valve port insert is taken out after the volume of the valve port insert is slightly changed, and the valve port insert is extruded by a plastic head to enter a central cavity of a valve body.

Referring to fig. 1 and 3, the lower end of the extension connecting pipe 2 is in threaded connection in the valve cavity 101, and the upper end of the extension connecting pipe 2 is in threaded connection with the magnetic isolation pipe assembly 3, so that the installation is convenient; a medium flow passage 201 communicating with the valve chamber 101 is provided in the extension joint pipe 2. According to the structure, newton's law of cooling is adopted, after a lengthened connecting pipe is additionally arranged at the middle section of the electromagnetic valve, a medium enters the electromagnetic valve cavity, under the action of the medium flow channel 201 and the outer wall of the electromagnetic valve cavity, the surface area of the ultralow temperature, which is in contact with metal, is increased, the gasification speed of the medium is increased, the influence on the coil is greatly reduced, and the coil is kept to operate efficiently. In addition, the lengthened connecting pipe structure is convenient for the installation and the use of the electromagnetic valve in the low-temperature medium switch control pipeline; because in the pipeline that ultralow temperature medium flows, for medium heat preservation, be equipped with the heat preservation outside the pipeline, when the solenoid valve was installed at ultralow temperature pipeline, extension connecting pipe highly was higher than the heat preservation, and after the installation was accomplished, solenoid valve coil assembly was located outside the heat preservation, made things convenient for coil power cord's connection.

Referring to fig. 1 and 4, the valve rod assembly 4 includes a movable iron core 41 slidably mounted in the magnetic isolation tube assembly 3, a valve port sealing assembly 42 disposed in the valve cavity 101 for opening and closing the valve guide port 104, and a connecting rod 43 penetrating through the medium flow passage 201, wherein the upper end of the connecting rod 43 is movably connected with the movable iron core 41, and the lower end of the connecting rod 43 is connected with the valve port sealing assembly 42. According to the structure, only the connecting rod is arranged in the lengthening connecting pipe, the current situation that the more compact and better the structure of the conventional electromagnetic valve is broken, the space in the inner cavity of the lengthening connecting pipe is remained relatively large, the convection of ultralow-temperature medium and air is facilitated, the temperature of the lengthening connecting pipe is increased, and the influence of the lengthening connecting pipe on a coil is weakened.

Referring to fig. 4 and 6, the valve port sealing assembly 42 includes a sealing seat 421 fixedly connected to the lower end of the connecting rod 43, a valve port sealing member 422 is disposed at the lower end of the sealing seat 421, and a tapered sealing portion 4221 adapted to seal with the pilot valve port 104 is disposed at the lower end of the valve port sealing member 422; when the electromagnetic valve is closed, the sealing seat 421 can swing under the driving of the connecting rod 43, so that the conical sealing portion 4221 and the valve guide port 104 can be automatically adjusted to reach the optimal sealing position. The connecting rod adopts a pendulum clock type design and a conical sealing part, when the movable iron core moves up and down, due to the existence of machining errors, when the absolute center movement cannot be ensured, the valve port sealing piece can automatically swing and adjust to an optimal sealing point after entering the valve port by the pendulum clock type design, so that the sealing reliability of the electromagnetic valve is ensured.

Referring to fig. 4 and 6, the outer side of the sealing seat 421 is sleeved with a compression spring seat 423, and a limiting boss 202 for limiting the compression spring seat 423 is arranged on the inner wall of the lengthened connecting pipe 2; the lower extreme of sealing seat 421 is provided with pressure spring flange 4211, and pressure spring 424 has been supported between pressure spring seat 423 and the pressure spring flange 4211, and pressure spring 424 makes valve port sealing member 422 have the trend of moving towards pilot valve port 104 all the time. According to the structure, under the action of the pressure spring and the pressure spring seat, the valve port sealing assembly 42 and the pilot valve port are kept at the same center, the force value of the spring force can be adjusted timely, meanwhile, the design that the spring is closest to the sealing position is adopted, so that the spring force exerts the optimal force value, and the automatic adjustment of the sealing position is facilitated.

Referring to fig. 8, the sealing surface angle of the tapered sealing portion 4221 is 60 degrees, and the valve guide port 104 is tapered and the sealing surface angle thereof is 90 degrees. Because of the characteristic of hard sealing, the electromagnetic valve adopts linear sealing modes with different angles, the sealing surface of the pilot valve port adopts an angle of 90 degrees, and the valve port sealing piece is designed into an angle of 60 degrees, when the valve port sealing pieces are matched in pairs, an included angle is generated, and the included angle is a final intersection point, namely the optimal sealing position.

Referring to fig. 4 and 6, the pressure spring seat 423 is provided with a diversion hole 4231, and the medium runner 201 is communicated with the valve cavity 101 through the diversion hole 4231; in the closed state of the electromagnetic valve, the pressure of the medium flow passage 201 is larger than the pressure of the valve cavity 101 due to the area ratio difference, so that the valve port sealing piece 422 tightly closes the valve guide port 104, and the valve closing is more reliable, thereby preventing leakage.

Referring to fig. 6, the upper end of the sealing seat 421 is provided with an upper mounting groove in which the end of the connecting rod 43 is seated and fixed by a first fixing pin 425; the lower end of the sealing seat 421 is provided with a lower mounting groove, and the end of the valve port sealing member 422 is disposed in the lower mounting groove and fixed by the second fixing pin 426, so that the connection is stable and the installation is convenient.

Referring to fig. 7, the solenoid valve adopts engineering plastics to carry out hard sealing (the valve port sealing piece 422 is made of engineering plastics), and has extremely high concentricity requirement on the up-and-down movement of the valve port sealing component; the combined valve port sealing assembly is concentrically machined, namely, a connecting rod at one end of the valve port sealing assembly 42 is clamped in a clamp Y of machining equipment, when the valve port sealing assembly rotates at a high speed, the valve port sealing member 422 is subjected to secondary machining by a cutter, and the machining of the conical sealing portion 4221 is finished by turning and grinding, so that the valve port sealing member and the connecting rod are always kept at the same central position.

Referring to fig. 4 and 5, a movable cavity 411 is provided at the lower end of the movable core 41, a limit sleeve 412 is fixed at the upper end of the connecting rod 43, and the limit sleeve 412 is loosely arranged in the movable cavity 411 to enable the connecting rod 43 to swing and slide up and down, i.e. a gap is provided between the limit sleeve 412 and the inner wall of the movable cavity 411 to ensure that the connecting rod 43 can rotate, swing and slide up and down; the connecting rod 43 is sleeved with a positioning sleeve 413, a gap is reserved between the positioning sleeve 413 and the connecting rod 43, and the positioning sleeve 413 is fixed with the movable iron core 41 to prevent the limiting sleeve 412 from falling out of the movable cavity 411.

Referring to fig. 10 and 11, in the closed state of the solenoid valve, the movable iron core 41 abuts against the stop collar 412 under the action of gravity, and the stop collar 412 and the positioning collar 413 are disposed at intervals. When the electromagnetic valve is opened, the electromagnetic coil generates electromagnetic force, the movable iron core 41 moves upwards under the action of the electromagnetic force to acquire a certain speed, and the initial movement stroke is L2; after the movable iron core 41 moves to the position sleeve 413 abutting against the limit sleeve 412, the movable iron core 41 instantly drives the connecting rod 43 to overcome the elastic force of the pressure spring to move upwards, so that the valve port sealing assembly 42 opens the pilot valve port 104; during the opening process, the total stroke of the movable iron core 41 is L1, and the actual opening degree of the solenoid valve is L, i.e., l1—l2=l. The structure adopts the design of small drift diameter and ultra-large stroke, increases the instant speed of opening, and has quicker response and more reliable opening; the electromagnetic force required by the operation and attraction of the movable iron core and the fixed iron core is greatly reduced, the power of a coil required by the operation of the electromagnetic valve is reduced, the power of the coil is reduced, and the cost of the coil can be reduced.

Referring to fig. 1, a first sealing ring 501 is installed between the upper end of the extension connection pipe 2 and the magnetic isolation pipe assembly 3, and a second sealing ring 502 is installed between the lower end of the extension connection pipe 2 and the valve body 1, which is beneficial to improving sealing performance. Referring to fig. 1 and 9, the electromagnetic coil assembly 6 is installed on the outer side of the magnetic isolation tube assembly 3, and the magnetic isolation tube assembly 3 and the electromagnetic coil assembly 6 are both in the prior art, and specific structures are not described again. The electromagnetic coil assembly 6 is fixed with the magnetic isolation tube assembly 3 through a flat gasket 601 and a fixing nut 602, a lower sealing gasket 603 is arranged between the magnetic isolation tube assembly 3 and the electromagnetic coil assembly 6, an upper sealing gasket 604 is arranged between the flat gasket 601 and the magnetic isolation tube assembly 3, and an O-shaped ring 605 is arranged between the fixing nut 602 and the flat gasket 601. When the electromagnetic valve is filled with ultralow-temperature medium such as liquid nitrogen, the whole electromagnetic valve is gasified and frosted instantly, and when the electromagnetic valve works for a long time, the coil melts into condensed water after generating temperature; the electromagnetic valve adopts three waterproof seals of the coil, so that condensed water cannot enter the coil, and the coil can be ensured to operate effectively for a long time.

The electromagnetic valve for the ultralow temperature medium is simple in structure, rapid to assemble and convenient to maintain, and can be widely applied to pipeline devices in petrochemical industry, heating ventilation and air conditioning, fire protection, ship reworking, environmental protection and other industries by additionally arranging the lengthened connecting pipe, changing the valve rod opening mode and improving the sealing performance of the valve port sealing piece and the electromagnetic coil.

The foregoing is merely a preferred embodiment of the present utility model, and it should be noted that it will be apparent to those skilled in the art that several modifications and variations can be made without departing from the technical principle of the present utility model, and these modifications and variations should also be regarded as the scope of the utility model.

Claims (10)

1. A direct acting solenoid valve for ultra-low temperature media comprising:

the valve comprises a valve body (1), wherein a valve cavity (101), a medium inlet (102) and a medium outlet (103) which are communicated with the valve cavity (101) are arranged on the valve body, and a pilot valve opening (104) which is used for communicating with the medium outlet (103) is arranged at the bottom of the valve cavity (101);

the lower end of the lengthened connecting pipe (2) is in threaded connection with the valve cavity (101), the upper end of the lengthened connecting pipe is in threaded connection with the magnetic isolation pipe assembly (3), and a medium flow passage (201) communicated with the valve cavity (101) is arranged in the lengthened connecting pipe;

the valve rod assembly (4) comprises a movable iron core (41) which is slidably arranged in the magnetism isolating pipe assembly (3), a valve port sealing assembly (42) which is arranged in the valve cavity (101) and used for opening and closing the pilot valve port (104) and a connecting rod (43) which is arranged in the medium flow passage (201) in a penetrating way; the upper end of the connecting rod (43) is movably connected with the movable iron core (41), and the lower end of the connecting rod is connected with the valve port sealing assembly (42); the valve port sealing assembly (42) comprises a sealing seat (421) fixedly connected with the lower end of the connecting rod (43), a valve port sealing element (422) is arranged at the lower end of the sealing seat (421), a pressure spring (424) is sleeved on the outer side of the sealing seat (421), and the pressure spring (424) always enables the valve port sealing element (422) to have a trend of moving towards the pilot valve port (104).

2. A direct-acting solenoid valve for ultra-low temperature media as claimed in claim 1 wherein: the lower end of the valve port sealing piece (422) is provided with a conical sealing part (4221) which is matched and sealed with the pilot valve port (104); when the valve is closed, the sealing seat (421) can swing under the drive of the connecting rod (43), so that the conical sealing part (4221) and the pilot valve (104) can be automatically adjusted to reach the optimal sealing position.

3. A direct-acting solenoid valve for ultra-low temperature media as claimed in claim 1 wherein: the outside of the sealing seat (421) is sleeved with a pressure spring seat (423), and a limiting boss (202) for limiting the pressure spring seat (423) is arranged on the inner wall of the lengthened connecting pipe (2); the lower extreme of seal seat (421) is provided with pressure spring flange (4211), pressure spring (424) have been supported between pressure spring seat (423) and pressure spring flange (4211).

4. A direct-acting solenoid valve for ultra-low temperature media as claimed in claim 3 wherein: the pressure spring seat (423) is provided with a diversion hole (4231), and the medium runner (201) is communicated with the valve cavity (101) through the diversion hole (4231); in a closed state, the pressure of the medium flow passage (201) is larger than the pressure of the valve cavity (101), so that the valve port sealing piece (422) tightly closes the pilot valve port (104).

5. A direct-acting solenoid valve for ultra-low temperature media as claimed in claim 1 wherein: the lower end of the movable iron core (41) is provided with a movable cavity (411), the upper end of the connecting rod (43) is fixedly provided with a limiting sleeve (412), and the limiting sleeve (412) is loosely arranged in the movable cavity (411) so that the connecting rod (43) can swing and slide up and down; a positioning sleeve (413) is sleeved outside the connecting rod (43), and the positioning sleeve (413) is fixed with the movable iron core (41) to prevent the limiting sleeve (412) from falling out of the movable cavity (411);

in a closed state, the movable iron core (41) is abutted against the limiting sleeve (412), and the limiting sleeve (412) and the positioning sleeve (413) are arranged at intervals; when the valve is opened, the movable iron core (41) moves upwards, and after the positioning sleeve (413) abuts against the limiting sleeve (412), the positioning sleeve instantly drives the connecting rod (43) to move upwards, so that the valve port sealing assembly (42) opens the pilot valve port (104).

6. A direct-acting solenoid valve for ultra-low temperature media as claimed in claim 2 wherein: the sealing surface angle of the conical sealing part (4221) is 60 degrees, and the pilot valve opening (104) is conical and the sealing surface angle of the pilot valve opening is 90 degrees.

7. A direct-acting solenoid valve for ultra-low temperature media as claimed in claim 1 wherein: the bottom of the valve cavity (101) is fixedly provided with a valve port insert (105) in an interference fit mode, and the valve port insert (105) is provided with a valve port opening (104).

8. A direct-acting solenoid valve for ultra-low temperature media as claimed in claim 1 wherein: a first sealing ring (501) is arranged between the upper end of the lengthened connecting pipe (2) and the magnetic isolation pipe assembly (3), and a second sealing ring (502) is arranged between the lower end of the lengthened connecting pipe (2) and the valve body (1).

9. A direct-acting solenoid valve for ultra-low temperature media as claimed in claim 1 wherein: an electromagnetic coil assembly (6) is arranged on the outer side of the magnetic isolation tube assembly (3), and the electromagnetic coil assembly (6) is fixed with the magnetic isolation tube assembly (3) through a flat gasket (601) and a fixing nut (602); a lower sealing gasket (603) is arranged between the magnetic isolation tube assembly (3) and the electromagnetic coil assembly (6), an upper sealing gasket (604) is arranged between the flat gasket (601) and the magnetic isolation tube assembly (3), and an O-shaped ring (605) is arranged between the fixing nut (602) and the flat gasket (601).

10. A direct-acting solenoid valve for ultra-low temperature media as claimed in claim 2 wherein: an upper mounting groove is formed in the upper end of the sealing seat (421), and the end part of the connecting rod (43) is arranged in the upper mounting groove and is fixed through a first fixing pin (425); the lower end of the sealing seat (421) is provided with a lower mounting groove, and the end part of the valve port sealing piece (422) is arranged in the lower mounting groove and is fixed through a second fixing pin (426).