CN115899290A

CN115899290A - Ultra-low temperature direct-acting electromagnetic valve

Info

Publication number: CN115899290A
Application number: CN202310218705.XA
Authority: CN
Inventors: 毛杉海; 顾国云; 郑年泽
Original assignee: Yuyao Sanlixin Solenoid Valve Co ltd
Current assignee: Yuyao Sanlixin Solenoid Valve Co ltd
Priority date: 2023-03-09
Filing date: 2023-03-09
Publication date: 2023-04-04
Anticipated expiration: 2043-03-09
Also published as: CN115899290B

Abstract

The invention provides an ultralow-temperature direct-acting electromagnetic valve which comprises a valve body, a lengthened connecting pipe and a valve rod assembly, wherein 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 port which is communicated 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 magnetism isolating pipe assembly, and a medium flow passage communicated with the valve cavity is arranged in the lengthened connecting pipe; the valve rod component comprises a movable iron core which is slidably arranged in the magnetism isolating pipe component, a valve port sealing component which is arranged in the valve cavity and used for opening and closing the valve port, and a connecting rod which is arranged in the medium flow channel in a penetrating way, 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 component; the ultralow temperature direct-acting electromagnetic valve provided by the invention overcomes the defect that the existing electromagnetic valve is not suitable for ultralow temperature media.

Description

Ultra-low temperature direct-acting electromagnetic valve

Technical Field

The invention relates to the field of electromagnetic valves, in particular to an ultralow-temperature direct-acting electromagnetic valve.

Background

The solenoid valve is the most widely used and important actuator and control element in pipeline fluid conveying system, and is an indispensable device in the control system. The control mode of the electromagnetic valve control part to the main valve can be divided into a direct-acting type and a pilot-operated type, and the control mode that the reversing of the valve core of the main valve is directly pushed or dragged by the movable iron core of the electromagnet is called as the direct-acting type; the direct-acting electromagnetic valve is directly controlled by using the electromagnetic effect, so that the response speed is high, the structure is simple, the minimum starting pressure limit is avoided, the pollution resistance and the anti-interference capability of a valve port are high, the repeatability is good, the action is stable and reliable, the size is small, and the weight is light.

In a pipeline fluid conveying system, ultralow temperature media such as liquid nitrogen, liquid ammonia, liquid oxygen and the like are often required to be conveyed; in the existing electromagnetic valve, after the ultralow-temperature medium flows into the electromagnetic valve cavity from the medium inlet, the ultralow-temperature medium can quickly influence an actuating mechanism, so that the current of the actuating mechanism is reduced, and the electromagnetic force is weakened, so that the electromagnetic valve is easy to lose efficacy; the existing electromagnetic valve has a compact structure, a valve core has short stroke, the instantaneous opening speed is slow, the opening is unreliable, a high-power coil is needed, and the additional cost is increased; the sealing surface of the valve core can not automatically adjust and seal, so that the valve core and the valve guide port have poor sealing performance and are easy to leak; in addition, the coil assembly of the existing electromagnetic valve lacks a sealing structure, and when ultralow-temperature media are conveyed, condensed water generated outside can enter the coil to damage the electromagnetic valve, so that the service life is influenced.

Disclosure of Invention

The technical problem to be solved.

The invention aims to solve the problem of providing an ultralow temperature direct-acting electromagnetic valve so as to overcome the defect that the existing electromagnetic valve is not suitable for ultralow temperature medium transportation.

The second technical proposal.

In order to solve the technical problem, the invention provides an ultralow temperature direct-acting electromagnetic valve which comprises a valve body.

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 port which is communicated 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 magnetism isolating pipe assembly, and a medium flow passage communicated with the valve cavity is formed in the lengthened connecting pipe.

The valve rod component comprises a movable iron core which is slidably arranged in the magnetism isolating pipe component, a valve port sealing component which is arranged in the valve cavity and used for opening and closing the valve port, and a connecting rod which is arranged in the medium flow channel 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 component.

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

Furthermore, a compression spring seat is slidably sleeved on the outer side of the sealing seat, and a limiting boss for limiting the compression spring seat is arranged on the inner wall of the lengthened connecting pipe; the lower end of the sealing seat is provided with a pressure spring flange, a pressure spring is abutted between the pressure spring seat and the pressure spring flange, and the pressure spring always enables the valve port sealing element to have a tendency of moving towards the valve guide port. The pressure spring seat is provided with a flow guide hole, and the medium flow passage is communicated with the valve cavity through the flow guide hole; in the closed state, the pressure intensity of the medium flow passage is higher than the pressure intensity of the valve cavity, so that the valve port sealing element tightly closes the valve port.

Furthermore, a movable cavity is arranged at the lower end of the movable iron core, a limiting sleeve is fixed at the upper end of the connecting rod, and the limiting sleeve is loosely arranged in the movable cavity to enable the connecting rod to swing and slide up and down; a positioning sleeve is sleeved outside the connecting rod and fixed with the movable iron core to prevent the limiting sleeve from being separated from 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 is abutted against the limiting sleeve, the positioning sleeve instantaneously drives the connecting rod to move upwards, so that the valve port sealing assembly opens the valve guide port.

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

Furthermore, a valve port insert is fixedly mounted at the bottom of the valve cavity in an interference fit manner, and the valve guide port is arranged on the valve port insert.

Furthermore, a first sealing ring is installed between the upper end of the lengthened connecting pipe and the magnetism isolating pipe assembly, and a second sealing ring is installed between the lower end of the lengthened connecting pipe and the valve body.

Furthermore, an electromagnetic coil assembly is installed on the outer side of the magnetism isolating pipe assembly and is fixed with the magnetism isolating pipe assembly through a flat gasket and a fixing nut; the magnetic isolation pipe assembly and a lower sealing gasket are installed between the magnetic isolation pipe assemblies, an upper sealing gasket is installed between the flat gaskets and the magnetic isolation pipe assemblies, and O-shaped rings are installed between the fixing nuts and the flat gaskets.

Furthermore, an upper mounting groove is formed in the upper end of the sealing seat, and the end of the connecting rod is arranged in the upper mounting groove and 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 element is arranged in the lower mounting groove and fixed through a second fixing pin.

(III) the beneficial effects.

Compared with the prior art, the ultralow-temperature direct-acting electromagnetic valve provided by the invention has the following advantages.

1) The middle section of the electromagnetic valve is additionally provided with the lengthened connecting pipe, so that the contact surface area of the ultralow-temperature medium and 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 accelerated, the influence on the coil is greatly weakened, and the coil keeps efficient operation; secondly, only the connecting rod is arranged in the lengthened connecting pipe, the situation that the conventional electromagnetic valve is more compact and better in structure is broken through, the space reserved in the inner cavity of the lengthened connecting pipe is larger, the convection between an ultralow-temperature medium and air is facilitated, the temperature of the ultralow-temperature medium is increased, and the influence of the ultralow-temperature medium on the coil is weakened; and the lengthened connecting pipe structure also facilitates the installation and the use of the electromagnetic valve in the low-temperature medium switch control pipeline and facilitates 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 absolute central movement cannot be guaranteed, the pendulum clock type design can enable the valve port sealing element to automatically swing and adjust to the optimal sealing position after entering the valve port, so that the sealing reliability of the electromagnetic valve is guaranteed, and leakage is avoided.

3) The design of small drift diameter and super large stroke enables the electromagnetic valve to be opened by means of the acceleration of the movable iron core; when the valve is opened, the movable iron core firstly moves upwards to obtain a certain speed, and then the valve port sealing element is instantaneously driven to be separated 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 work attraction of the movable iron core and the fixed iron core is greatly reduced, the power of the coil required by the work of the electromagnetic valve is reduced, and the cost of the coil can be reduced due to the reduction of the power of the coil.

4) The coil adopts three waterproof sealing, adds lower sealing member in coil assembly bottom, and the sealing member is added to the higher authority, and O type circle is added to fixation nut department, makes the comdenstion water unable get into the coil inside, guarantees that the coil can effectual long-time operation.

Drawings

Fig. 1 is a schematic structural diagram of an ultra-low temperature direct-acting solenoid valve according to the present invention.

Fig. 2 is a schematic structural diagram of an ultra-low temperature direct-acting electromagnetic valve body according to the present invention.

Fig. 3 is a schematic structural view of an ultra-low temperature direct-acting type solenoid valve lengthening connection pipe according to the present invention.

Fig. 4 is a schematic structural diagram of a valve stem assembly of an ultra-low temperature direct-acting solenoid valve according to the present invention.

FIG. 5 is a schematic structural diagram of the movable iron core and the connecting rod of the ultra-low temperature direct-acting electromagnetic valve of the present invention.

FIG. 6 is a schematic structural view of a valve port sealing assembly of an ultra-low temperature direct-acting solenoid valve according to the present invention.

FIG. 7 is a schematic structural diagram of the ultra-low temperature direct-acting solenoid valve during the machining of the conical sealing portion.

FIG. 8 is a schematic structural view of the valve port sealing member and the pilot valve port sealing connection of the ultralow temperature direct-acting solenoid valve of the present invention.

FIG. 9 is a schematic diagram of the connection structure of the insulating tube assembly and the electromagnetic coil assembly of the ultra-low temperature direct-acting solenoid valve of the present invention.

Fig. 10 is a schematic structural diagram of the opening stroke of the movable iron core of the ultra-low temperature direct-acting electromagnetic valve of the present invention.

Fig. 11 is a schematic structural view of an ultra-low temperature direct-acting solenoid valve according to the present invention after being opened.

The corresponding part names for the various reference numbers in the figures are: 1. a valve body; 101. a valve cavity; 102. a media inlet; 103. a media outlet; 104. a valve guide port; 105. a valve port insert; 2. lengthening the connecting pipe; 201. a medium flow passage; 202. a limiting boss; 3. a magnetism isolating pipe assembly; 4. a valve stem assembly; 41. a movable iron core; 42. a valve port sealing assembly; 43. a connecting rod; 411. a movable cavity; 412. a limiting 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 pressure spring flange; 4221. a tapered seal portion; 4231. a flow guide hole; 501. a first seal ring; 502. a second seal ring; 6. an electromagnetic coil assembly; 601. a flat gasket; 602. fixing a nut; 603. a lower seal; 604. an upper seal gasket; 605. an O-shaped ring; y, machining equipment clamp; l1, total stroke of the movable iron core; l2, the initial stroke of the movable iron core; l, actual opening degree of the electromagnetic valve.

Detailed description of the preferred embodiments

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Referring to fig. 1 to 11, the present invention provides an ultra-low temperature direct-acting solenoid valve, which comprises a valve body 1, an elongated connecting pipe 2, a magnetic isolation pipe assembly 3 and a valve rod assembly 4.

Referring to fig. 1 and 2, a valve cavity 101, a medium inlet 102 and a medium outlet 103 are disposed in the middle of the upper end of the valve body 1 and are respectively communicated with the valve cavity 101 at two sides, a pilot valve port 104 for communicating with the medium outlet 103 is disposed at the bottom of the valve cavity 101, and the opening and closing of the solenoid valve is realized by opening and closing 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 the pilot valve 104 is arranged on the valve port insert 105. This structure adopts interference fit's processing mode, guarantees that valve port mold insert and valve body are sealed firmly and reach zero leakage. When the valve port insert 105 is assembled, because absolute concentricity is difficult to realize due to interference fit, 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 a plastic head is used for extruding the valve port insert into a central cavity of a valve body.

Referring to fig. 1 and 3, the lower end of the lengthened connecting pipe 2 is connected in the valve cavity 101 through threads, and the upper end of the lengthened connecting pipe 2 is connected with the magnetism isolating pipe assembly 3 through threads, so that the installation is convenient; a medium flow passage 201 communicated with the valve cavity 101 is arranged in the lengthened connecting pipe 2. This structure adopts Newton's cooling law, adds the extension connecting pipe in the solenoid valve middle section, makes the medium get into the solenoid valve cavity after, under the effect of medium runner 201 and its outer wall, makes the superficial area increase of ultra-low temperature and metal contact, makes medium gasification speed accelerate, weakens greatly the influence that causes the coil, makes the coil keep the efficient function. 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 of in the pipeline that the ultra-low temperature medium flows, for the medium keeps warm, the pipeline is equipped with the heat preservation outward, and when the solenoid valve was installed at the ultra-low temperature pipeline, the extension connecting pipe highly was higher than the heat preservation, and after the installation was accomplished, solenoid valve coil pack was located outside the heat preservation, made things convenient for the connection of coil power cord.

Referring to fig. 1 and 4, the valve rod assembly 4 includes a movable iron core 41 slidably mounted in the magnetism isolating pipe assembly 3, a valve port sealing assembly 42 disposed in the valve chamber 101 for opening and closing the valve port 104, and a connecting rod 43 disposed in the medium flow passage 201 in a penetrating manner, wherein an upper end of the connecting rod 43 is movably connected to the movable iron core 41, and a lower end of the connecting rod 43 is connected to the valve port sealing assembly 42. According to the structure, only the connecting rod is arranged in the lengthened connecting pipe, the situation that the more compact the structure of a conventional electromagnetic valve is better is broken, the space reserved in the inner cavity of the lengthened connecting pipe is larger, the convection between an ultralow-temperature medium and air is facilitated, the temperature of the ultralow-temperature medium is increased, and the influence of the ultralow-temperature medium on the 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 conical sealing portion 4221 adapted to seal the pilot valve port 104 is disposed at the lower end of the valve port sealing member 422; when the solenoid valve is closed, the sealing seat 421 can be driven by the connecting rod 43 to swing, so that the conical sealing portion 4221 and the pilot valve port 104 automatically adjust to an optimal sealing position. According to the structure, 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 processing errors, when absolute center movement cannot be guaranteed, the pendulum clock type design can enable the valve port sealing element to automatically swing and adjust to an optimal sealing point after entering the valve port, so that the sealing reliability of the electromagnetic valve is guaranteed.

Referring to fig. 4 and 6, a pressure spring seat 423 is slidably sleeved outside the sealing seat 421, 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 end of the sealing seat 421 is provided with a pressure spring flange 4211, a pressure spring 424 is abutted between the pressure spring seat 423 and the pressure spring flange 4211, and the pressure spring 424 always makes the valve port sealing element 422 have a tendency to move towards the pilot valve port 104. The structure makes the valve port sealing component 42 and the pilot valve port keep the same center under the action of the pressure spring and the pressure spring seat, the force value can be adjusted timely by the spring force, and meanwhile, the design that the spring is closest to the sealing position is adopted, so that the spring force can exert the optimal force value, and the automatic adjustment of the sealing position is facilitated.

Referring to fig. 8, the conical sealing portion 4221 has a sealing surface angle of 60 degrees, the pilot valve port 104 is conical, and the sealing surface angle is 90 degrees. Due to 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, the valve port sealing element is designed into an angle of 60 degrees, and an included angle is generated after two valves are matched with each other and is a final intersection point, namely an optimal sealing position.

Referring to fig. 4 and 6, the pressure spring seat 423 is provided with a flow guide hole 4231, and the medium flow passage 201 is communicated with the valve cavity 101 through the flow guide hole 4231; in the closed state of the solenoid valve, due to the area ratio difference, the pressure of the medium flow channel 201 is greater than that of the valve cavity 101, so that the valve port sealing element 422 tightly closes the valve guide port 104, the valve is more reliably closed, and leakage is prevented.

Referring to fig. 6, the upper end of the sealing seat 421 is provided with an upper mounting groove, and the end of the connecting rod 43 is disposed in the upper mounting groove and fixed by a first fixing pin 425; the lower extreme of seal receptacle 421 is provided with down the mounting groove, and the tip of valve port sealing member 422 is arranged in down the mounting groove and is fixed through second fixed pin 426, connects firmly, and it is convenient to install.

Referring to fig. 7, the solenoid valve is hard sealed by engineering plastics (the valve port sealing element 422 is made of engineering plastics), and has extremely high requirement on the concentricity of the up-and-down movement of the valve port sealing assembly; the combined valve port sealing assembly is concentrically processed, namely, a connecting rod at one end of the valve port sealing assembly 42 is clamped in a machining equipment clamp Y, and when the valve port sealing assembly rotates at a high speed, the valve port sealing member 422 is secondarily processed by a cutter, and the conical sealing part 4221 is processed in a cutting and grinding mode, 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, 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 fixed with a limiting sleeve 412, and the limiting 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 formed between the limiting 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 link rod 43 is externally sleeved with a positioning sleeve 413, a gap is also formed between the positioning sleeve 413 and the link rod 43, and the positioning sleeve 413 is fixed with the movable iron core 41 to prevent the limiting sleeve 412 from being separated from the movable cavity 411.

Referring to fig. 10 and 11, in the closed state of the electromagnetic valve, the movable iron core 41 abuts against the position-limiting sleeve 412 under the action of gravity, and at this time, the position-limiting sleeve 412 and the positioning sleeve 413 are arranged at an interval. 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 obtain a certain speed, and the initial movement stroke is L2; after the movable iron core 41 moves until the positioning sleeve 413 abuts against the limiting sleeve 412, the movable iron core 41 instantly drives the connecting rod 43 to overcome the elasticity of the pressure spring to move upwards, so that the valve port sealing component 42 opens the pilot valve port 104; in the opening process, the total stroke of the movable iron core 41 is L1, and the actual opening degree of the electromagnetic valve is L, that is, L1-L2= L. The structure adopts the design of small drift diameter and super large stroke, increases the instantaneous speed of opening, and has quicker response and more reliable opening; the electromagnetic force required by the work attraction of the movable iron core and the fixed iron core is greatly reduced, the power of the coil required by the work of the electromagnetic valve is reduced, and the cost of the coil can be reduced due to the reduction of the power of the coil.

Referring to fig. 1, a first sealing ring 501 is installed between the upper end of the lengthened connecting pipe 2 and the magnetism isolating pipe assembly 3, and a second sealing ring 502 is installed between the lower end of the lengthened connecting pipe 2 and the valve body 1, which is beneficial to improving the sealing performance. Referring to fig. 1 and 9, an electromagnetic coil assembly 6 is installed outside the magnetism isolating pipe assembly 3, and both the magnetism isolating pipe assembly 3 and the electromagnetic coil assembly 6 are in the prior art, and detailed structures are not described again. The electromagnetic coil assembly 6 is fixed with the magnetism isolating pipe assembly 3 through a flat gasket 601 and a fixing nut 602, a lower sealing gasket 603 is installed between the magnetism isolating pipe assembly 3 and the electromagnetic coil assembly 6, an upper sealing gasket 604 is installed between the flat gasket 601 and the magnetism isolating pipe assembly 3, and an O-shaped ring 605 is installed between the fixing nut 602 and the flat gasket 601. When the electromagnetic valve is electrified with ultralow temperature media such as liquid nitrogen, the external part of the whole electromagnetic valve is gasified and then frosted instantly, and when the electromagnetic valve works for a long time, the coil is melted into condensed water after generating temperature; this solenoid valve adopts coil three waterproof sealing, makes inside the comdenstion water can't get into the coil, guarantees that the coil can effectual long-time operation.

The ultra-low temperature direct-acting type electromagnetic valve provided by the embodiment has the advantages that the ultra-low temperature direct-acting type electromagnetic valve is enabled to be suitable for conveying of ultra-low temperature media by additionally arranging the lengthened connecting pipe, changing the opening mode of the valve rod and improving the sealing performance of the valve port sealing element and the electromagnetic coil, is simple in structure, rapid to assemble and convenient to maintain, and can be widely applied to pipeline devices of petrochemical industry, heating and ventilation air conditioners, fire fighting, ship heavy industry, environmental protection and other industries.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. An ultra-low temperature direct-acting solenoid valve, 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 (1), and a pilot valve port (104) which is used for communicating 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 magnetism isolating 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 installed in the magnetism isolating pipe assembly (3) in a sliding mode, a valve port sealing assembly (42) which is arranged in the valve cavity (101) and used for opening and closing the valve guide port (104), and a connecting rod (43) which penetrates through the medium flow channel (201); 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 component (42).

2. The ultra-low temperature direct-acting solenoid valve as claimed in claim 1, wherein: 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), and a conical sealing part (4221) matched with the valve guide port (104) in a sealing mode is arranged at the lower end of the valve port sealing element (422); when the valve is closed, the sealing seat (421) can swing under the driving of the connecting rod (43), so that the conical sealing part (4221) and the valve guide port (104) are automatically adjusted to reach the optimal sealing position.

3. The ultra-low temperature direct-acting solenoid valve as claimed in claim 2, wherein: a pressure spring seat (423) is slidably sleeved on the outer side of the sealing seat (421), and a limiting boss (202) for limiting the pressure spring seat (423) is arranged on the inner wall of the lengthened connecting pipe (2); a pressure spring flange (4211) is arranged at the lower end of the sealing seat (421), a pressure spring (424) is abutted between the pressure spring seat (423) and the pressure spring flange (4211), and the pressure spring (424) always enables the valve port sealing member (422) to have a tendency of moving towards the guide valve port (104).

4. The ultra-low temperature direct-acting solenoid valve as claimed in claim 3, wherein: a flow guide hole (4231) is formed in the pressure spring seat (423), and the medium flow channel (201) is communicated with the valve cavity (101) through the flow guide hole (4231); in the closed state, the pressure of the medium flow passage (201) is higher than that of the valve cavity (101), so that the valve port sealing element (422) tightly closes the valve guide port (104).

5. The ultra-low temperature direct-acting solenoid valve 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 fixed with a limiting sleeve (412), and the limiting sleeve (412) is loosely arranged in the movable cavity (411) to enable the connecting rod (43) to 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 being separated from the movable cavity (411);

in a closed state, the movable iron core (41) abuts 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 instantaneously drives the connecting rod (43) to move upwards, so that the valve port sealing assembly (42) opens the valve guide port (104).

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

7. The ultra-low temperature direct-acting solenoid valve 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 (104) is arranged on the valve port insert (105).

8. The ultra-low temperature direct-acting solenoid valve as claimed in claim 1, wherein: the upper end of the lengthened connecting pipe (2) and the magnetism isolating pipe assembly (3) are provided with a first sealing ring (501), and the lower end of the lengthened connecting pipe (2) and the valve body (1) are provided with a second sealing ring (502).

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

10. The ultra-low temperature direct-acting solenoid valve as claimed in claim 2, wherein: an upper mounting groove is formed in the upper end of the sealing seat (421), and the end of the connecting rod (43) is arranged in the upper mounting groove and 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 of the valve port sealing element (422) is arranged in the lower mounting groove and fixed through a second fixing pin (426).