CN107366750B

CN107366750B - Stop valve for refrigerating system

Info

Publication number: CN107366750B
Application number: CN201610312342.6A
Authority: CN
Inventors: 不公告发明人
Original assignee: Zhejiang Sanhua Intelligent Controls Co Ltd
Current assignee: Zhejiang Sanhua Intelligent Controls Co Ltd
Priority date: 2016-05-11
Filing date: 2016-05-11
Publication date: 2020-05-01
Anticipated expiration: 2036-05-11
Also published as: CN107366750A

Abstract

The invention provides a stop valve for a refrigerating system, which can realize reliable positioning of a valve rod through matching of the valve rod and a valve body without auxiliary parts such as a check ring and the like, thereby avoiding potential safety hazards caused by installation of the auxiliary parts and improving the use safety. The stop valve provided by the invention comprises a valve body with a valve port and a valve rod for opening and closing the valve port, wherein the valve body is provided with a first positioning part, and the valve rod is provided with a second positioning part; when the valve port is fully opened, the first positioning part is matched with the second positioning part to position the valve rod. According to the stop valve, the valve body and the valve rod are provided with the mutually matched positioning parts, so that the valve rod can be positioned by means of the valve body after the valve rod is installed, auxiliary parts such as check rings are not needed, the valve rod cannot be positioned reliably due to the fact that the auxiliary parts are not installed in place or are installed wrongly, safety accidents such as flying-out of the valve rod are avoided, and the use safety and reliability of the stop valve are improved.

Description

Stop valve for refrigerating system

Technical Field

The invention relates to the technical field of refrigeration systems, in particular to a stop valve for a refrigeration system.

Background

Various valves are commonly used in refrigeration systems to control the refrigerant, for example, a shut-off valve is used in an air conditioning system to communicate an outdoor unit with an indoor unit. The shutoff valve is an operable manual opening and closing valve that shuts off a fluid passage such as a refrigerant before the air conditioner is installed and communicates the refrigerant passage when the air conditioner is installed.

Referring to fig. 1, fig. 1 is a cross-sectional view of a typical shut-off valve of the prior art.

As shown in fig. 1, in the prior art, a stop valve generally comprises a valve body 1 ', a valve rod 2 ', a valve cap 3 ', an O-ring 4 ', a retainer ring 5 ', a connecting pipe nut 6 ', a seal cap 7 ', a valve core 8 ', a filling valve cap 9 ', and the like; the valve core 8 'is used for evacuation or refrigerant filling, and when the refrigerant is filled into the air conditioner, the valve core 8' can be filled. Wherein, the valve body 1' is provided with a first channel and a second channel, and a valve seat is arranged between the first channel and the second channel; a valve rod 2 'is arranged in the valve body 1', and the valve rod 2 'is provided with a valve head in a cone frustum shape and a thread part in threaded fit with the inner wall of the valve body 1'; by rotating the valve rod 2 ', the valve rod 2' moves up and down along the axial direction, the valve head is contacted with or separated from the valve seat, and the first channel is communicated with or disconnected from the second channel. In addition, the O-shaped ring is arranged between the valve body 1 'and the valve rod 2' and is used for preventing the refrigerant between the valve body 1 'and the valve rod 2' from leaking; the valve body 1 ' is also provided with a third channel communicated with the refrigerant, and a valve core 8 ' is arranged at the communication part of the third channel and the interior of the valve body 1 ' and is used as a filling end for filling the refrigerant; the valve cap 3 ' and the filling valve cap 9 ' are used for secondary sealing, and the connecting pipe nut 6 ' is used for connecting with an indoor unit.

Before the air conditioner is installed, the valve rod 2' is in contact seal with the valve seat through the valve head in the shape of a truncated cone, so that the communication between the second channel on the outdoor system side and the first channel on the indoor side is cut off and closed; after the air conditioner is installed, the valve rod 2 ' is moved up to the position of the retainer ring 5 ' (as shown in fig. 1) by rotating the valve rod 2 ' to communicate the first passage with the second passage.

In the existing stop valve, when the valve rod 2 'moves upwards to communicate the first channel and the second channel, the retainer ring 5' presses the valve rod 2 'downwards to position the valve rod 2' when the valve port is fully opened. That is to say, when the valve port is fully opened, the positioning of the valve rod 2 'is realized by the check ring 5', if the check ring 5 'is neglected to be installed or is not installed in place, the risk of flying out of the valve rod 2' exists, and safety accidents are easily caused.

Therefore, how to design a stop valve for a refrigeration system to improve the positioning reliability of a valve rod and further improve the safety of the stop valve becomes a technical problem that needs to be solved by those skilled in the art.

Disclosure of Invention

The invention aims to provide a stop valve for a refrigerating system, which can realize reliable positioning of a valve rod through matching of the valve rod and a valve body without auxiliary parts such as a check ring and the like, thereby avoiding potential safety hazards caused by installation of the auxiliary parts and improving the use safety.

In order to solve the technical problem, the invention provides a stop valve for a refrigerating system, which comprises a valve body with a valve port and a valve rod for opening and closing the valve port, wherein the valve body is provided with a first positioning part, and the valve rod is provided with a second positioning part; when the valve port is fully opened, the first positioning part is matched with the second positioning part to position the valve rod.

According to the stop valve, the valve body and the valve rod are provided with the mutually matched positioning parts, so that the valve rod can be positioned by means of the valve body after the valve rod is installed, auxiliary parts such as check rings are not needed, the valve rod cannot be positioned reliably due to the fact that the auxiliary parts are not installed in place or are installed wrongly, safety accidents such as flying-out of the valve rod are avoided, and the use safety and reliability of the stop valve are improved.

Optionally, the first positioning portion presses against the second positioning portion toward a valve closing direction to position the valve rod.

Optionally, an inner wall of the valve body has an annular step facing the valve port to form the first detent; the valve rod is provided with an annular convex part which is far away from the valve port so as to form the second positioning part.

Optionally, the outer diameter of the second positioning portion decreases in a direction away from the valve port to form a cone which abuts against and is sealed with the edge of the first positioning portion.

Optionally, the valve rod has a first sealing portion, and a first sealing groove for filling a sealing element is formed between the second positioning portion and the first sealing portion, so that the valve rod is sealed with the valve body when the valve port is fully opened.

Optionally, the valve rod further has a second sealing part for sealing the valve port, and the outer diameter of the second sealing part is smaller than or equal to that of the first sealing part.

Optionally, the first sealing portion and the second sealing portion are connected by a connecting portion, the connecting portion has a recess portion with a radial dimension smaller than that of the second sealing portion, and when the valve port is fully opened, the recess portion forms a flow passage for refrigerant.

Optionally, the second sealing portion has a tapered surface that seals with the valve port line.

Optionally, the second sealing portion includes a first sealing head and a second sealing head that are sequentially connected in an axial direction, the first sealing head is matched with the valve port, and a second sealing groove for filling a sealing member is formed between the first sealing head and the second sealing head, so that the valve port is sealed with the valve body when fully closed.

Optionally, the valve body comprises a first cavity, a second cavity, a third cavity, a fourth cavity and a fifth cavity which are sequentially communicated in the axial direction and sequentially increased in inner diameter; the first cavity is in threaded fit with the valve rod, and the inner walls of the second cavity and the third cavity are connected to form an annular step as the first positioning part; the third cavity is used for accommodating the second positioning part to the first sealing part; the fourth cavity and the fifth cavity are both communicated with an external connecting pipe and are communicated through the valve port; the valve rod is installed in the valve body from the fifth cavity to the first cavity.

Drawings

FIG. 1 is a cross-sectional view of a typical shut-off valve of the prior art;

FIG. 2 is a cross-sectional view of a shut-off valve provided by the present invention in one embodiment with the valve port fully open;

FIG. 3 is a cross-sectional view of the shut-off valve of FIG. 2 shown fully closed;

FIG. 4 is a cross-sectional view of a valve body of a stop valve provided by the present invention in one arrangement;

FIG. 5 is a cross-sectional view of a valve stem of a stop valve provided by the present invention in one arrangement;

FIG. 6 is a cross-sectional view of a valve stem of a stop valve provided by the present invention in another arrangement.

In fig. 1:

the valve comprises a valve body 1 ', a valve rod 2 ', a valve cap 3 ', an O-shaped ring 4 ', a retainer ring 5 ', a connecting pipe nut 6 ', a sealing cap 7 ', a valve core 8 ' and a filling valve cap 9 ';

FIGS. 2 to 6:

the valve comprises a valve body 1, a valve port 11, a first positioning part 12, a first cavity 13, a second cavity 14, a third cavity 15, a fourth cavity 16, a fifth cavity 17 and a sleeve 18;

the valve rod 2, the second positioning portion 21, the first sealing portion 22, the first sealing groove 23, the second sealing portion 24, the tapered surface 241, the first sealing head 242, the second sealing head 243, the second sealing groove 244, the connecting portion 25, the concave portion 26, and the threaded portion 27.

Detailed Description

The core of the invention is to provide a stop valve for a refrigerating system, which can realize the reliable positioning of a valve rod 2 through the matching of the valve rod 2 and a valve body 1 without auxiliary parts such as a check ring and the like, thereby avoiding the potential safety hazard caused by the installation of the auxiliary parts and improving the use safety.

The shutoff valve for a refrigeration system provided by the invention is specifically described below with reference to the accompanying drawings, so that a person skilled in the art can accurately understand the technical scheme of the invention.

The axial direction described herein, i.e. the direction of extension of the valve stem 2, is referred to the valve stem 2; the circumferential direction is the circumferential direction, and the direction in which the diameter of the valve rod 2 is located is the radial direction.

For convenience of description, the axial direction may also be defined as an up-down direction, the moving direction when the valve rod 2 closes the valve port 11 is a down direction, and the moving direction when the valve rod 2 opens the valve port 11 is an up direction. However, it should be understood that the upper and lower portions are merely for convenience of description, and do not represent any limitation on the direction in which the shutoff valve is provided; the up-down directions described herein may be described with reference to the orientations in fig. 2-6.

The terms first, second, etc. described herein are used only for distinguishing between different elements having the same or similar structure or different structures and do not denote any particular order or importance.

As shown in fig. 2 and 3, the invention provides a stop valve for a refrigeration system, comprising a valve rod 2 and a valve body 1, wherein the valve body 1 is provided with a valve port 11, and the valve rod 2 is installed in the valve body 1 and is used for opening and closing the valve port 11; the valve body 1 is provided with a first positioning part 12, and the valve rod 2 is provided with a second positioning part 21 which can be matched with the first positioning part 12; when the valve port 11 is fully opened, the first positioning portion 12 cooperates with the second positioning portion 21, and the valve rod 2 is positioned by the valve body 1.

It can be seen that, according to the present invention, through the arrangement of the first positioning portion 12 and the second positioning portion 21, the valve body 1 realizes positioning of the valve rod 2, so that the valve rod 2 is kept at the position where the valve port 11 is fully opened, without using auxiliary components such as a check ring. On one hand, the auxiliary part is not needed, so that the influence on the positioning of the valve rod 2 caused by the installation of the auxiliary part, such as the risk of flying out of the valve rod 2 caused by the neglected installation, the improper installation or the wrong installation of the auxiliary part, is avoided; on the other hand, compare with the auxiliary member location such as adoption retaining ring among the prior art, utilize the structure cooperation of valve body 1 and valve rod 2 to realize that valve rod 2 fixes a position and can effectively improve the positioning reliability, and then improve the safety in utilization of valve rod 2.

Specifically, the first positioning portion 12 and the second positioning portion 21 have various structural forms as long as they can be engaged with each other to position the valve stem 2 in the fully opened state of the valve port 11. For example, the first positioning portion 12 and the second positioning portion 21 may be detachably connected in a snap-fit manner, an insertion manner, an abutting manner, or the like, so as to achieve the fitting and positioning when the valve port 11 is fully opened, and to release the valve rod 2 by releasing the fitting and positioning when the valve port 11 is fully closed or other working positions. In other words, the person skilled in the art can appropriately set the matching structure of the first positioning portion 12 and the second positioning portion 21 as required to realize the positioning and releasing of the valve rod 2.

In an embodiment, the first positioning portion 12 and the second positioning portion 21 may be in abutting engagement, so that the first positioning portion 12 presses against the second positioning portion 21 toward the valve closing direction to limit the valve rod 2 to continue moving toward the valve opening direction, and further limit the valve rod 2 at a position corresponding to the full opening of the valve port 11, thereby positioning the valve rod 2 when the valve port 11 is fully opened.

In detail, the inner wall of the valve body 1 may be provided with an annular step facing the valve port 11 as the first positioning portion 12; the valve stem 2 may be provided with an annular projection facing away from the valve port 11 as the second detent 21. When the valve rod 2 moves towards the valve opening direction, the annular convex part moves close to the annular step, when the valve rod 2 moves to the full opening of the valve port 11, the annular convex part is abutted to the annular step, and the annular step is abutted to the annular convex part towards the valve closing direction, so that the valve rod 2 is positioned.

The annular step and the annular convex part can be matched structures, namely the annular convex part can be arranged to be a step structure away from the valve port 11 so as to be matched with the annular step serving as the first positioning part 12; alternatively, the structure of the annular protrusion may be other structural forms as long as the annular protrusion can abut against the annular step to position the valve rod 2, such as a bump structure.

In one embodiment, the second detent 21 may be provided as a cone having an outer diameter that decreases in a direction away from the valve port 11, thereby abutting against an edge of the first detent 12 and forming a line-sealing engagement. The annular step can be a two-stage step, wherein the edge of one stage of step is bent along the axial direction and connected with the other stage of step, and the edge is formed at the edge.

The annular step forms a step surface on the inner wall of the valve body 1, the second positioning part 21 of the valve rod 2 is a cone of which the outer diameter is gradually reduced in the direction departing from the valve port 11, and the outer diameter of the cone cannot be completely matched with the step surface, so that the cone is in linear contact with the edge of the step surface; on one hand, the linear contact enables the cone and the edge of the annular step to be in linear compression fit so as to realize the positioning of the valve rod 2; on the other hand, the hard seal of valve rod 2 and valve body 1 has been realized to linear contact, has formed twice between valve rod 2 and the valve body 1 sealed from this, and one is O type circle soft seal, and the other one is the hard seal that forms between valve rod 2 and the valve body 1 to avoid refrigerant inflow valve body 1 to be used for holding the cavity of valve rod 2, improved sealing reliability.

In addition, in the stop valve of the present invention, the valve stem 2 may further include a first sealing portion 22, a first sealing groove 23 for filling a sealing member may be provided between the second positioning portion 21 and the first sealing portion 22, and the second positioning portion 21 may be located in a direction in which the first sealing portion 22 is away from the valve port 11, that is, above the first sealing portion 22 in fig. 2 and 3. When the valve port 11 is fully opened, the second positioning part 21 is matched with the first positioning part 12 of the valve body 1, and a linear hard seal is formed, so that primary sealing of the valve body 1 and the valve rod 2 is realized; the first seal portion 22 seals an upper chamber of the valve body 1, and seals the inner wall of the valve body 1, that is, secondary sealing between the valve body 1 and the valve stem 2, by a seal member filled in the first seal groove 23. As shown in fig. 2, by the above-mentioned secondary sealing, it can be effectively prevented that the refrigerant in the middle cavity of the valve body 1 permeates into the upper cavity of the valve body 1 when the valve port 11 is fully opened, thereby preventing the refrigerant from damaging the driving part of the valve rod 2 in the upper cavity, and ensuring the normal operation of the valve rod 2.

The valve stem 2 may also have a second sealing portion 24 for sealing the valve port 11. Wherein, the outer diameter of the second sealing portion 24 may be smaller than or equal to the outer diameter of the first sealing portion 22. When the valve port 11 is fully opened, the second sealing portion 24 occupies the refrigerant flow channel, and when the outer diameter of the second sealing portion 24 is smaller than or equal to the outer diameter of the first sealing portion 22, the volume of the second sealing portion 24 can be effectively reduced, so that the volume of the refrigerant flow channel occupied by the second sealing portion 24 is reduced, and the refrigerant flow rate in unit time is increased. Moreover, the valve rod 2 can be installed into the valve body 1 in an inverted manner, that is, the valve rod 2 is installed into the valve body 1 from bottom to top, and since the second sealing portion 24 is located below the first sealing portion 22, when the outer diameter of the second sealing portion 24 is smaller than or equal to the outer diameter of the first sealing portion 22, the installation of the valve rod 2 can be facilitated, which is described in detail below with respect to the installation of the valve rod 2.

The first sealing portion 22 and the second sealing portion 24 may be connected by a connecting portion 25, and the second positioning portion 21, the first sealing portion 22, the connecting portion 25, and the second sealing portion 24 may be connected in order in the axial direction. When the valve port 11 is fully opened, the first sealing portion 22 is sealed with the valve body 1, and at this time, the connecting portion 25 and the second sealing portion 24 are both disposed in the refrigerant flowing space, thereby reducing the flow rate of the refrigerant. In view of the above technical problem, the connecting portion 25 of the present application may be provided with a recess 26 having a radial dimension smaller than that of the first sealing portion 22 and the second sealing portion 24, so as to reduce a space occupied by the connecting portion 25, so that the recess 26 forms a flow passage for the refrigerant, and the influence of the arrangement of the connecting portion 25 on the refrigerant flow when the valve port 11 is fully opened is reduced.

In order to shorten the opening and closing stroke of the valve rod 2, a person skilled in the art can increase the axial size of the connecting part 25, and further reduce the axial displacement of the valve rod 2 during opening and closing the valve; however, when the axial dimension of the connecting portion 25 increases, it occupies a flow passage of the refrigerant, and the flow rate decreases. Therefore, the connecting portion 25 of the present invention is provided with the concave portion 26 to reduce the volume of the connecting portion 25, and the concave portion 26 serves as a flow passage for the refrigerant to increase the flow rate.

Referring to fig. 4, in the stop valve of the present invention, the valve body 1 may include a first cavity 13, a second cavity 14, a third cavity 15, a fourth cavity 16, and a fifth cavity 17 which are sequentially communicated along the axial direction and have sequentially increased inner diameters, and the first cavity 13 may be sequentially communicated from top to bottom, wherein the first cavity 13 is used for being in threaded fit with the valve rod 2 to drive the valve rod 2 to move up and down along the axial direction of the valve body 1, so as to open and close the valve port 11; the first chamber 13 to the third chamber 15 are used for accommodating the part of the valve rod 2 above the second sealing part 24, a second positioning part 21 can be arranged below the threaded part 27 of the valve rod 2, the upper part of the second positioning part 21 is placed in the second chamber 14, and the lower part of the second positioning part is arranged at the upper part of the third chamber 15; the inner walls of the second chamber 14 and the third chamber 15 are connected to form the above-described annular step as the first positioning portion 12; the lower portion of the second positioning portion 21 to the first sealing portion 22 are in the third chamber 15; the fourth chamber 16 and the fifth chamber 17 are both communicated with external connecting pipes, one of the external connecting pipes is communicated with the indoor side, the other external connecting pipe is communicated with the outdoor side, and the fourth chamber 16 is communicated with the fifth chamber 17 through a valve port 11.

When the valve body 1 adopts the structure, the valve rod 2 can be installed in the valve body 1 from the fifth cavity 17 to the first cavity 13, namely, the valve rod is installed in the valve body 1 from the bottom to the top in the directions of fig. 2-3 and fig. 5; at the position corresponding to the full opening of the valve port 11, the second positioning portion 21 of the valve rod 2 is matched with the first positioning portion 12 of the valve body 1, so that the installation and the positioning of the valve rod 2 are realized. Because first location portion 12 can support and press second location portion 21 towards the valve closing direction, during the valve rod 2 flip-chip, if the installation targets in place, first location portion 12 just can apply the effort towards the valve closing direction to valve rod 2, avoids valve rod 2 departure, has improved the security of valve rod 2 installation.

In order to flip the valve rod 2, the inner diameters of the fourth cavity 16 and the fifth cavity 17 of the valve body 1 are larger than the inner diameter of the second sealing portion 24, and at this time, in order to seal the second sealing portion 24 and the valve port 11, a sleeve 18 may be built in the fifth cavity 17, and the sleeve 18 may be installed after the valve rod 2 is installed, so that the valve port 11 capable of sealing with the second sealing portion 24 is formed at one end of the sleeve 18, as shown in fig. 4.

The valve stem 2 of the present invention will be described in detail below with reference to fig. 5 and 6.

As shown in fig. 5, in an embodiment, the valve stem 2 of the present invention may include a threaded portion 27, a second positioning portion 21, a first sealing portion 22, a connecting portion 25, and a second sealing portion 24, which are connected in sequence from top to bottom; it should be noted that the thread portion 27 is formed at the upper section of the valve rod 2, and the top end of the valve rod 2 is provided with an installation angle hole, which may be a hexagonal hole, and the thread portion 27 of the valve rod 2 is engaged with the internal thread of the valve body 1 by operating the hexagonal hole, so that the valve rod 2 is screwed into the valve body 1, and similarly, when the valve port needs to be opened or closed, the hexagonal hole provided at the top end of the valve rod 2 and the thread engagement relationship between the thread portion 27 and the valve body 1 can be operated.

The second positioning part 21 may be a cone with an outer diameter decreasing from bottom to top, and a conical inclined surface of the cone forms a sealing surface so as to seal with the valve body 1; the first seal groove 23 between the first seal portion 22 and the second positioning portion 21 may be filled with a seal to form a seal with the valve body 1; an end of the second sealing portion 24 facing the valve port 11 may be formed with a tapered surface 241 to form a sealing surface capable of line-sealing with the valve port 11. By adopting the structure, when the valve port 11 is fully opened, the double sealing of the valve body 1 and the valve rod 2 is realized through the second positioning part 21 and the sealing element filled in the first sealing groove 23; when the valve port 11 is fully closed, the valve port 11 is hermetically connected by a second seal. Meanwhile, the second sealing portion 24 abutting against the valve port 11 may also be a soft sealing structure, and it should be noted that the material of the sealing structure is not limited at all here.

Furthermore, the concave portion 26 may be formed by various ways, for example, a notch, a groove, etc. may be formed on the connecting portion 25, and a part of the connecting portion 25 may be recessed to form the concave portion 26. In one specific arrangement, a groove may be formed in the outer wall of the connecting portion 25 to form the recess 26. The outer wall of the connecting portion 25 is with respect to the axial centerline of the valve stem 2, and the direction away from the axial centerline is outward. The shape and the opening position of the groove are not limited as long as the groove is opened in the outer wall of the connecting portion 25 to form a portion having a smaller radial dimension than the first seal portion 22 and the second seal portion 24 as the concave portion 26.

As shown in fig. 6, in another embodiment, the valve stem 2 may include a first sealing head 242 and a second sealing head 243 connected in sequence along the axial direction, the first sealing head 242 is engaged with the valve port 11, and a second sealing groove 244 for filling a sealing member is formed between the first sealing head 242 and the second sealing head 243; when the first sealing head 242 closes the valve port 11 and the valve port 11 is fully closed, the second sealing head 243 is located below the valve port 11, and the sealing element in the second sealing groove 244 seals the valve body 1 and the valve rod 2. As shown in fig. 6, the second sealing head 243 may be located below the first sealing head 242, and when the sleeve 18 is installed in the valve body 1 to form the valve port 11, the second sealing head 243 may be located in the sleeve 18; meanwhile, a first sealing head 242 may be further provided, and an end surface of the first sealing head 242 facing the valve port 11 is provided with a structural form such as a conical surface, so as to realize a sealing connection with the valve port 11.

In this embodiment, the recess 26 can be provided in accordance with the previous embodiment, and will not be described herein. In view of the arrangement of the first and second sealing heads 242 and 243, the size of the connecting portion 25 can be reduced as appropriate, and the size of the recess 26 can be adjusted as needed.

It can be understood that the stop valve of the invention does not need to adopt auxiliary parts such as a check ring and the like to realize the positioning of the valve rod, and also does not need to adopt a copper valve cap to be matched and positioned with the check ring and the like, so that the copper valve cap can be eliminated, and the cost is reduced.

The stop valve is used for a refrigeration system, and is particularly suitable for a split air conditioner or other refrigeration circulation systems which take R22, R407C, R410A and the like as refrigerants. In view of the fact that the shutoff valve for the refrigeration system includes many components and the structure of each component is also complex, only the valve rod 2 and related components thereof are described herein, and other parts are not described in detail with reference to the prior art.

The shutoff valve for the refrigeration system provided by the invention is described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the core concepts of the present invention. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. A stop valve for a refrigerating system comprises a valve body (1) with a valve port (11) and a valve rod (2) for opening and closing the valve port (11), and is characterized in that the valve body (1) is provided with a first positioning part (12), and the valve rod (2) is provided with a second positioning part (21); when the valve port (11) is fully opened, the first positioning part (12) is matched with the second positioning part (21) to position the valve rod (2); the valve rod (2) is also provided with a first sealing part (22), a connecting part (25) and a second sealing part (24) which are sequentially connected along the axial direction, the first sealing part (22) is used for realizing the sealing with the valve body (1) when the valve port (11) is fully opened, the second sealing part is used for sealing the valve port (11), the connecting part (25) is provided with a concave part (26) with a radial dimension smaller than that of the first sealing part (22) and the second sealing part (24), and when the valve port (11) is fully opened, the concave part (26) forms a flow channel of refrigerant;

a first sealing groove (23) for filling a sealing element is arranged between the second positioning part (21) and the first sealing part (22) so as to seal the valve port (11) when the valve port is fully opened and the valve body (1).

2. A stop valve according to claim 1, wherein the first positioning portion (12) presses against the second positioning portion (21) in a valve closing direction to position the valve stem (2).

3. A shut-off valve according to claim 2, wherein the inner wall of the valve body (1) has an annular step towards the valve port (11) to form the first detent (12); the valve stem (2) has an annular projection facing away from the valve port (11) to form the second detent (21).

4. A shut-off valve according to claim 3, characterised in that the outer diameter of the second detent (21) decreases in the direction away from the valve port (11) to form a cone which abuts against and seals against the edge of the first detent (12).

5. A stop valve as claimed in any one of claims 1 to 4, wherein an angle-fitting hole is provided at an end of the valve stem (2) facing away from the valve port (11), a threaded portion (27) is provided at a portion thereof located between the angle-fitting hole and the second positioning portion (21), and the valve body (1) is provided with an internal thread which is engaged with the threaded portion (27).

6. A shut-off valve according to claim 5, characterised in that the outer diameter of the second sealing portion (24) is equal to or less than the outer diameter of the first sealing portion (22).

7. A shut-off valve according to claim 6, characterised in that the second sealing portion (24) has a conical surface (241) that seals with the valve port (11).

8. The stop valve of claim 6, characterized in that the second sealing portion (24) comprises a first sealing head (242) and a second sealing head (243) which are axially connected in sequence, the first sealing head (242) is matched with the valve port (11), and a second sealing groove (244) for filling a sealing element is arranged between the first sealing head (242) and the second sealing head (243) so as to be sealed with the valve body (1) when the valve port (11) is fully closed.

9. The shut-off valve according to claim 5, characterized in that the valve body (1) comprises a first chamber (13), a second chamber (14), a third chamber (15), a fourth chamber (16) and a fifth chamber (17) which are axially communicated in sequence and have successively increasing internal diameters; the first cavity (13) is in threaded fit with the valve rod (2), and the inner walls of the second cavity (14) and the third cavity (15) are connected to form an annular step as the first positioning part (12); the third cavity (15) is used for accommodating the second positioning part (21) to the first sealing part (22); the fourth cavity (16) and the fifth cavity (17) are communicated with an external connecting pipe and are communicated through the valve port (11); the valve rod (2) is installed in the valve body (1) from the fifth cavity (17) to the first cavity (13).