CN114484067A

CN114484067A - Sampling valve

Info

Publication number: CN114484067A
Application number: CN202210068688.1A
Authority: CN
Inventors: 曲德湖; 王聪聪; 章星; 黄涨泽; 周悠翔
Original assignee: Lianggong Valve Group Co ltd
Current assignee: Lianggong Valve Group Co ltd
Priority date: 2022-01-20
Filing date: 2022-01-20
Publication date: 2022-05-13

Abstract

The utility model relates to a sampling valve relates to the technical field of sampling valve, and it includes valve body, sampling tube, valve rod and valve block, the vertical slip of valve rod is worn to locate on the valve body, be provided with the support frame on the valve body, the thread bush is equipped with the support cap on the support frame, just the support cap can vertical motion, the upper end of valve rod with the support cap rotates to be connected. Through setting up and the vertical sliding connection's of valve body valve rod, when the rotating supported the cap, supported the cap and can drive the vertical motion of valve rod to reduce valve rod and sealing filler and appear relative pivoted risk, and then weaken the shearing force of valve rod to sealing filler, reduce the risk that wearing and tearing appear in sealing filler, and then improve the sealing stability of sample valve.

Description

Sampling valve

Technical Field

The application relates to the field of sampling valves, in particular to a sampling valve.

Background

The sampling valve is also one of valves, is mainly used for obtaining medium samples in pipelines or equipment, and is widely applied to occasions where chemical analysis is often performed on the medium samples.

The sampling valve in the related art generally includes a valve body, a valve rod screwed to the valve body, and a valve block fixed to the bottom of the valve rod, wherein a sealing filler is filled between the valve rod and the valve body in order to improve the sealing property between the valve rod and the valve body. When the user rotates the valve rod, the valve rod drives the valve block to move upwards, so that the sampling tube at the bottom of the valve body is opened.

In view of the above-mentioned related art, since the valve rod is in threaded connection with the valve body, when the valve rod is rotated and the valve rod drives the valve block to move upward, the valve rod and the sealing packing rotate and slide relatively. However, when the valve rod and the sealing filler rotate relatively, the valve rod generates a strong tangential force, and the risk of abrasion of the sealing filler exists easily in the past, so that the sealing effect of the sampling valve is influenced and needs to be improved.

Disclosure of Invention

In order to reduce the risk of abrasion of the sealing filler, the application provides a sampling valve.

The application provides a sampling valve adopts following technical scheme:

the utility model provides a sampling valve, includes valve body, sampling tube, valve rod and valve block, the vertical slip of valve rod is worn to locate on the valve body, be provided with the support frame on the valve body, the threaded sleeve is equipped with the support cap on the support frame, just the support cap can vertical motion, the upper end of valve rod with the support cap rotates to be connected.

Through adopting above-mentioned technical scheme, when the rotating supported the cap, supported the cap and can drive valve rod vertical motion to realize the control that the sampling tube opened and close. Because the support cap can drive the valve rod vertical motion to reduce the risk that relative rotation appears in valve rod and sealing filler, and then weaken the shearing force of valve rod to sealing filler. The design can effectively reduce the risk of abrasion of the sealing filler, thereby improving the sealing stability of the sampling valve.

Optionally, the support cap include the control cap and the activity set up in the inboard control block of control cap, the groove of stepping down has been seted up to the lower tip of control block, the upper end of valve rod is inserted and is located the inslot of stepping down, the inner wall in groove of stepping down rolls and inlays and be equipped with a plurality of balls, the lateral wall of valve rod is seted up with a plurality of the annular guide way of ball matched with, the control cap with the control block passes through the locking piece and forms detachable connection.

Through adopting above-mentioned technical scheme, through the cooperation of ball and guide way, reduce the frictional force between control block and the valve rod, can improve the rotation smoothness of control block and control cap, can reduce the valve rod again and appear pivoted risk to improve sample valve's stability in use. Simultaneously, utilize the locking piece to fix control cap and control block for the control cap can be dismantled, thereby makes the control cap change alone, improves the maintenance convenience.

Optionally, the locking piece includes that the screw thread wears to locate screw on the control cap and set up in locking groove on the control block, locking groove confession the screw carries out screw-thread fit, the constant head tank has been seted up to the lateral wall of control block, the support groove has been seted up to the inner wall of control cap, the constant head tank with support the relative and formation circular shape spacing hole in groove, spacing downthehole interpolation is equipped with the spacer pin.

Through adopting above-mentioned technical scheme, when needs assemble the control cap, insert the spacing limit in the constant head tank, then overlap the control cap on the control block, at this moment, constant head tank and support groove form spacing hole to the spacer pin is inserted and is located spacing downthehole. Subsequently, the screw is screwed into the locking groove, and the control cap can be assembled. Simultaneously, the screw is unscrewed from the locking groove, and then the control cap can be disassembled. Through the locking piece that sets up simple structure, simple operation, convenient unblock and locking, realize the quick unblock and the locking of control cap to work efficiency when carrying out the dismouting to the control cap is improved. Simultaneously, through the cooperation of spacer pin and spacing hole for the drive control block that the control cap can be stable rotates, reduces the relative pivoted risk of appearing in control block and control cap, thereby makes the control block can drive the stable vertical motion of valve rod, and then improves the stability in use of sample valve. Meanwhile, the design can facilitate assembly of the sampling valve by production personnel, and further improve the production efficiency.

Optionally, the support frame includes set up in the piece of accepting on the valve body and set up in the cover of accepting on the piece of accepting, accept the hole has been seted up on the piece of accepting, the vertical slip of valve rod is worn to locate in the accept hole, control cap thread bush is located accept and is sheathe in.

Through adopting above-mentioned technical scheme, when needs assemble the support frame, will hold the piece fixed with the valve body, then will hold the adapter sleeve and accept the piece and be connected, can realize the assembly to the support frame to make things convenient for the assembly of producers to the sample valve, further improve production efficiency.

Optionally, the receiving sleeve is sleeved on the receiving block in a threaded manner, and the receiving block and the receiving sleeve form a detachable connection through a fastener.

Through adopting above-mentioned technical scheme, through setting up the cover of accepting that can dismantle, accomplish when the control cap and dismantle the back, the user can take off the cover of accepting to make the user can change alone and maintain accepting the cover, and then improve the maintenance convenience.

Optionally, the fastener includes the mounting groove, accepts the groove and the fastening pin, the mounting groove set up in the inner wall of accepting the cover, accept the groove set up in the lateral wall of accepting the piece, the mounting groove with accept the groove relative and form annular fastening hole, the fastening pin is inserted and is located in the fastening hole, accept and sheathe in and seted up the pilot hole, the mounting groove with the pilot hole intercommunication.

By adopting the technical scheme, when the bearing sleeve needs to be fixed, the bearing sleeve is sleeved on the bearing block in a threaded manner, so that the mounting groove and the bearing groove are aligned to form the fastening hole. And then, the fastening pin penetrates through the assembly hole, then the fastening pin is inserted into the fastening hole, and then the fastening pin, the receiving block and the receiving sleeve are welded and fixed, so that the receiving block and the receiving sleeve can be fixed. Through setting up simple structure, simple operation's fastener, realize the quick fixation of accepting the piece and accepting the cover to realize the rapid Assembly who accepts the cover, and then improve production efficiency.

Optionally, the fixed cover of lower extreme of valve rod is equipped with the holding ring, the holding ring can butt the lower surface of bearing piece, works as the valve piece seals when the sampling tube, the holding ring with the distance between the bearing piece does the stroke of opening of valve rod.

Through adopting above-mentioned technical scheme, through setting up the holding ring, realize the vertical ascending maximum distance of sliding of valve rod and injectd, reduce the risk that the valve rod deviates from the valve body, and then improve the stability in use of sample valve.

Optionally, the length of the engagement section of the control cap and the receiving sleeve is an engagement stroke, the distance of downward movement of the receiving sleeve relative to the receiving block is a compensation stroke, the opening stroke is smaller than the engagement stroke, and the sum of the compensation stroke and the opening stroke is larger than the engagement stroke.

Through adopting above-mentioned technical scheme, when needs are dismantled advancing the sampling valve line, the control cap of rotating earlier drives parts such as valve rod and moves to make the holding ring and accept the piece butt. Subsequently, the fastening pin is broken with the receiving block and the welding point of the receiving sleeve, and the fastening pin is pulled out of the fastening hole. Then, the control cap is held, the bearing sleeve is rotated to move downwards, when the bearing sleeve is separated from the control cap, the control cap can be detached, and then the bearing sleeve is rotated reversely, so that the bearing sleeve can be detached. The design enables the disassembly of the control cap, the receiving sleeve and other components to be unlocked only by forming a specific mode and a specific sequence, and only when the unlocking is completely met, the control cap and the receiving sleeve can be disassembled and are not easy to be perceived, so that the anti-theft effect of the sampling valve is improved. Meanwhile, other locking mechanisms are not needed in the design, and the automatic anti-theft capacity of the sampling valve can be realized only by utilizing the position relation and the ingenious matching among all the parts, so that the linkage among all the parts can be improved, the reasonable utilization of resources can be improved, and the practicability is improved.

Optionally, a packing groove is formed in the inner wall of the bearing block, a gland is sleeved on the valve rod in a vertical sliding mode, the gland is detachably connected with the bearing block, and the gland can be inserted into the packing groove.

Through adopting above-mentioned technical scheme, through setting up the detachable gland, in case when wearing and tearing appear in the sealed packing of packing groove, the user can change sealed packing to guarantee the life and the stability in use of sample valve. Meanwhile, the sealing filler can be replaced in time, and the risk of liquid or gas leakage is reduced, so that the risk of liquid or gas polluting the environment is reduced, and the environment-friendly effect is improved.

Optionally, a screw rod is vertically fixed on the bearing block, a nut is sleeved on the screw rod in a threaded manner, a mounting hole for the screw rod to pass through is formed in the pressing cover, and the nut is used for pressing the pressing cover onto the upper surface of the bearing block.

Through adopting above-mentioned technical scheme, with the nut from the screw rod spiral shell, then can stimulate gland upward movement to make the gland take out from the packing groove, then can dismantle the sealing packing. In a similar way, the nut and the screw rod are in threaded fit, and when the nut compresses the gland onto the bearing block, the gland can be fixed. Through setting up the convenient gland of dismantling, realize the quick replacement of sealing filler, and then improve work efficiency.

In summary, the present application includes at least one of the following beneficial technical effects:

by arranging the valve rod vertically and slidably connected with the valve body, when the supporting cap is rotated, the supporting cap can drive the valve rod to vertically move, so that the risk of relative rotation between the valve rod and the sealing filler is reduced, the shearing force of the valve rod on the sealing filler is weakened, the risk of abrasion of the sealing filler is reduced, and the sealing stability of the sampling valve is improved;

the positioning ring is arranged, so that the maximum vertical upward sliding distance of the valve rod is limited, the risk that the valve rod is separated from the valve body is reduced, and the use stability of the sampling valve is improved;

through the cooperation of parts such as control cap, socket for the dismantlement of parts such as control cap and socket needs specific mode and specific order to form just can the unblock, only satisfies completely, just can dismantle control cap and socket, and difficult quilt is perceived, thereby improves the theftproof effect of sample valve.

Drawings

Fig. 1 is a schematic overall structure diagram of an embodiment of the present application.

Fig. 2 is a partial cross-sectional view of an embodiment of the present application.

Fig. 3 is a schematic view of the internal structure of the valve body in the embodiment of the present application.

Fig. 4 is an enlarged schematic view of the region a in fig. 3.

Fig. 5 is an enlarged schematic view of the region B in fig. 3.

Fig. 6 is an enlarged schematic view of region C in fig. 2.

Description of reference numerals: 1. a valve body; 2. a sampling tube; 3. a valve stem; 4. a valve block; 5. a support frame; 51. a bearing block; 52. a bearing sleeve; 6. a support cap; 61. a control cap; 62. a control block; 7. a yielding groove; 8. a ball bearing; 9. a guide groove; 10. a locking member; 101. a screw; 102. a locking groove; 11. positioning a groove; 12. a support groove; 13. a limiting hole; 14. a spacing pin; 15. a bearing hole; 16. a fastener; 161. mounting grooves; 162. a receiving groove; 163. a fastening hole; 164. a fastening pin; 17. an assembly hole; 18. a positioning ring; 19. starting a stroke; 20. an engagement stroke; 21. compensating the stroke; 22. a packing groove; 23. a gland; 24. a screw; 25. mounting holes; 26. and a nut.

Detailed Description

The present application is described in further detail below with reference to figures 1-6.

The embodiment of the application discloses a sampling valve. Referring to fig. 1 and 2, the sampling valve includes valve body 1 and fig. 2, and the bottom integrated into one piece intercommunication of valve body 1 has sampling tube 2 to make things convenient for the user to get the quick access of sample. Valve rod 3 is worn to be equipped with on the vertical slip of valve body 1, and the lower tip integrated into one piece of valve rod 3 has the valve block 4 that can seal the port on sampling tube 2 to realize the control that sampling tube 2 opened and close.

Referring to fig. 2 and 3, the upper end of the valve body 1 is provided with a support frame 5, the valve rod 3 is located inside the support frame 5, a support cap 6 is threaded on the support frame 5, and the support cap 6 can vertically move. Meanwhile, the upper end of the valve stem 3 is rotatably connected to the support cap 6, and the valve stem 3 and the support cap 6 are coaxial. When the support cap 6 is rotated, the support cap 6 drives the valve rod 3 and the valve block 4 to move vertically, so that the opening and closing of the sampling tube 2 are controlled.

Referring to fig. 3 and 4, the support cap 6 includes a control cap 61 disposed above the valve body 1, a control block 62 is disposed inside the control cap 61, a relief groove 7 is opened at a lower end of the control block 62, and an upper end of the valve rod 3 is inserted into the relief groove 7.

Referring to fig. 3 and 4, a plurality of balls 8 are embedded in the inner wall of the abdicating groove 7 in a rolling manner, and the balls 8 are uniformly distributed along the circumferential direction of the abdicating groove 7. Meanwhile, the side wall of the valve rod 3 is provided with an annular guide groove 9 along the circumferential direction thereof, and the plurality of balls 8 are respectively matched with the guide groove 9, so that the control cap 61 can rotate rapidly and stably.

Referring to fig. 3 and 4, a locking member 10 is provided between the control cap 61 and the control block 62, and the locking member 10 is used to fix the control block 62 and the control cap 61. At the same time, locking member 10 can restrict control block 62 from rotating relative to control cap 61, so that control block 62 can bring valve rod 3 into stable vertical movement.

Referring to fig. 3 and 4, the locking member 10 includes a screw 101 threaded through the cap 61, and a locking groove 102 for the screw 101 to be screwed is formed on an upper end surface of the control block 62. When the screw 101 is screwed into the locking groove 102, the control block 62 is connected to the control cap 61.

Referring to fig. 3 and 4, a pair of semicircular positioning grooves 11 is formed in the side wall of the control block 62, the pair of positioning grooves 11 are symmetrically distributed on two sides of the control block 62, and a pair of semicircular supporting grooves 12 is formed in the inner wall of the control cap 61. When the two positioning slots 11 are aligned with the corresponding support slots 12, the two positioning slots 11 and the two support slots 12 form two circular limiting holes 13, and limiting pins 14 are inserted into the two limiting holes 13, so as to reduce the risk of relative rotation between the control cap 61 and the control block 62.

When the control cap 61 needs to be installed, the two limit pins 14 are respectively inserted into the corresponding positioning grooves 11, then the control cap 61 is sleeved on the control block 62, the two positioning grooves 11 are respectively aligned with the corresponding support grooves 12 to form the limit holes 13, and meanwhile, the two limit pins 14 are respectively inserted into the corresponding limit holes 13. Subsequently, the screw 101 is screwed into the locking groove 102, and the top wall of the control cap 61 is brought into abutment with the two stopper pins 14, whereby the control cap 61 is assembled.

Referring to fig. 3 and 5, the supporting frame 5 includes a receiving block 51 fixedly connected to the upper end of the valve body 1, a receiving hole 15 is opened on the receiving block 51, and the valve rod 3 vertically slides and penetrates through the receiving hole 15. Meanwhile, the bearing block 51 is threaded with the bearing sleeve 52, the control cap 61 is threaded on the bearing sleeve 52, and the control block 62 is located inside the bearing sleeve 52. At the same time, the socket block 51 and the socket 52 are detachably connected by the fastener 16, so that the socket 52 can be detached.

Referring to fig. 3 and 5, the fastening member 16 includes two semicircular installation grooves 161 opened on the inner wall of the socket 52, and the two installation grooves 161 are symmetrically distributed on both sides of the socket 52. Two semicircular assembling holes 17 are formed in the side wall of the receiving sleeve 52, and the two mounting grooves 161 are respectively communicated with the corresponding assembling holes 17. The side wall of the receiving block 51 is provided with two semicircular receiving grooves 162, and the two receiving grooves 162 and the two mounting grooves 161 are aligned to form two circular fastening holes 163. Meanwhile, a fastening pin 164 is inserted into each fastening hole 163 to reduce the risk of relative rotation between the receiving block 51 and the receiving sleeve 52.

When the support frame 5 needs to be assembled, the receiving block 51 is fixedly connected with the valve body 1, and then the receiving sleeve 52 is screwed on the receiving block 51, at this time, the two receiving grooves 162 and the two mounting grooves 161 are aligned and form two fastening holes 163. Subsequently, the two fastening pins 164 are respectively inserted through the corresponding assembly holes 17, the two fastening pins 164 are respectively inserted into the corresponding fastening holes 163, and then the upper ends of the fastening pins 164 are welded and fixed to the receiving block 51 and the receiving sleeve 52, so that the assembly of the support frame 5 can be realized.

Referring to fig. 2 and 3, the lower end of the valve stem 3 is fixedly sleeved with a positioning ring 18, the positioning ring 18 is located below the bearing block 51, and the positioning ring 18 can abut against the lower surface of the bearing block 51 to realize the limitation of the maximum sliding tool of the valve stem 3 vertically upwards so as to reduce the risk of the valve stem 3 falling out of the valve body 1.

Referring to fig. 2 and 3, when valve block 4 closes off sampling tube 2, the distance between positioning ring 18 and receiving block 51 is the opening stroke 19 of valve stem 3, the length of the engagement segment of control cap 61 and receiving sleeve 52 is engagement stroke 20, and the distance that receiving sleeve 52 can move downward compared to receiving block 51 is compensation stroke 21. At the same time, the opening stroke 19 is smaller than the engagement stroke 20, and the sum of the compensation stroke 21 and the opening stroke 19 is greater than the engagement stroke 20.

When the control cap 61 and other parts need to be detached, the control cap 61 is rotated to drive the valve rod 3 and other parts to move upwards, and the positioning ring 18 is abutted to the bearing block 51. Subsequently, the welding points between the fastening pin 164 and the receiving block 51 and the receiving sleeve 52 are broken, and the fastening pin 164 is pulled out of the fastening hole 163.

Then, the control cap 61 is held, the receiving sleeve 52 is rotated to move downwards, and after the receiving sleeve 52 is separated from the control cap 61, the control cap 61 and the receiving sleeve 52 can be unlocked. At this time, the screw 101 is unscrewed from the locking groove 102, and the control cap 61 is pulled to move upward, and the control cap 61 is separated from the receiving sleeve 52.

Subsequently, the rotation socket 52 moves, and the socket 52 is moved upward. When the receiving sleeve 52 is separated from the receiving block 51, the receiving sleeve 52 can be detached. Since the control cap 61, the receiving sleeve 52 and other parts need to be disassembled in a specific mode and in a specific sequence to be unlocked, the disassembly is not easy to be noticed, and the anti-theft effect of the sampling valve is improved.

Referring to fig. 3 and 6, the packing groove 22 is opened on the inner wall of the receiving block 51, and the packing groove 22 extends to the upper surface of the receiving block 51 and communicates with the outside. The vertical sliding sleeve on the valve rod 3 is provided with a gland 23, the lower end part of the gland 23 can be inserted into the packing groove 22, and after the packing groove 22 is filled with the sealing packing, the gland 23 can compress the sealing packing in the packing groove 22.

Referring to fig. 3 and 6, a plurality of screws 24 are vertically and fixedly connected to the receiving block 51, a plurality of mounting holes 25 are formed in the pressing cover 23, and the screws 24 are respectively inserted into the corresponding mounting holes 25. Meanwhile, each screw 24 is threaded with a nut 26, and the two nuts 26 are used for pressing the gland 23 on the upper surface of the bearing block 51 together, so that the gland 23 and the bearing block 51 are fixed.

When the packing is to be replaced, the nut 26 is unscrewed and the nut 26 is separated from the screw 24, and then the gland 23 is pulled to move upward and the lower end portion of the gland 23 is removed from the packing groove 22. Then, the sealing filler is placed in the filler groove 22, and the gland 23 is pressed on the bearing block 51 by the nut 26, so that the sealing filler can be replaced.

The implementation principle of a sampling valve of the embodiment of the application is as follows: when the sampling tube 2 needs to be controlled to be opened and closed, the supporting cap 6 is rotated, and then the supporting cap 6 can drive the valve rod 3 to vertically move, so that the opening and closing of the sampling tube 2 are controlled. Because valve rod 3 only carries out vertical slip to reduce valve rod 3 and the risk that the relative rotation appears in the sealing filler, and then weaken valve rod 3 to the shearing force of sealing filler, reduce the risk that the wearing and tearing appear in the sealing filler, thereby improve the seal stability of sample valve. Simultaneously, each part adopts screw-thread fit's connected mode mostly in this design, reduces the requirement that the producer carries out welding operation to each part, can reduce the risk that the producer inhales the smoke and dust, can reduce the risk of smoke and dust polluted environment again to improve environmental protection effect.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The utility model provides a sampling valve, includes valve body (1), sampling tube (2), valve rod (3) and valve block (4), its characterized in that: valve rod (3) vertical slip is worn to locate on valve body (1), be provided with support frame (5) on valve body (1), threaded sleeve is equipped with support cap (6) on support frame (5), just support cap (6) can vertical motion, the upper end of valve rod (3) with support cap (6) rotate and connect.

2. A sampling valve according to claim 1, wherein: support cap (6) including control cap (61) and activity set up in control cap (61) inboard control block (62), the groove of stepping down (7) has been seted up to the lower tip of control block (62), the upper end of valve rod (3) is inserted and is located in the groove of stepping down (7), the inner wall roll of the groove of stepping down (7) inlays and is equipped with a plurality of ball (8), the lateral wall of valve rod (3) has been seted up with a plurality of ball (8) matched with annular guide way (9), control cap (61) with control block (62) form through locking piece (10) and can dismantle the connection.

3. A sampling valve according to claim 2, wherein: locking piece (10) wear to locate including the screw (101) on control cap (61) and set up in locking groove (102) on control block (62), locking groove (102) supply screw (101) carry out screw-thread fit, constant head tank (11) have been seted up to the lateral wall of control block (62), support groove (12) have been seted up to the inner wall of control cap (61), constant head tank (11) with support groove (12) are relative and form circular shape spacing hole (13), spacing hole (13) interpolation is equipped with spacer pin (14).

4. A sampling valve according to claim 2, wherein: the support frame (5) including set up in the piece (51) that holds on the valve body (1) and set up in hold in the cover (52) on the piece (51) that holds, hold and have seted up on the piece (51) and have accepted hole (15), valve rod (3) vertical slip is worn to locate in accepting hole (15), control cap (61) thread bush is located hold in the cover (52).

5. A sampling valve according to claim 4, wherein: the bearing sleeve (52) is sleeved on the bearing block (51) in a threaded manner, and the bearing block (51) and the bearing sleeve (52) form detachable connection through a fastener (16).

6. A sampling valve according to claim 5, wherein: the fastening piece (16) comprises a mounting groove (161), a bearing groove (162) and a fastening pin (164), the mounting groove (161) is formed in the inner wall of the bearing sleeve (52), the bearing groove (162) is formed in the side wall of the bearing block (51), the mounting groove (161) is opposite to the bearing groove (162) and forms an annular fastening hole (163), the fastening pin (164) is inserted into the fastening hole (163), an assembling hole (17) is formed in the bearing sleeve (52), and the mounting groove (161) is communicated with the assembling hole (17).

7. A sampling valve according to claim 5, wherein: the fixed cover of lower extreme of valve rod (3) is equipped with holding ring (18), holding ring (18) can the butt the lower surface of bearing piece (51), work as valve piece (4) are sealed during sampling tube (2), holding ring (18) with distance between bearing piece (51) does open stroke (19) of valve rod (3).

8. A sampling valve according to claim 7, wherein: the length of the engagement section of the control cap (61) and the receiving sleeve (52) is an engagement stroke (20), the distance of downward movement of the receiving sleeve (52) compared with the receiving block (51) is a compensation stroke (21), the opening stroke (19) is smaller than the engagement stroke (20), and the sum of the compensation stroke (21) and the opening stroke (19) is larger than the engagement stroke (20).

9. A sampling valve according to claim 4, wherein: packing groove (22) have been seted up to the inner wall of bearing piece (51), vertical slip cover is equipped with gland (23) on valve rod (3), gland (23) with bearing piece (51) can be dismantled the connection, just gland (23) can insert in packing groove (22).

10. A sampling valve according to claim 9, wherein: the bearing block (51) is vertically fixed with a screw rod (24), the screw rod (24) is provided with a nut (26) in a threaded sleeve manner, the gland (23) is provided with a mounting hole (25) for the screw rod (24) to pass through, and the nut (26) is used for pressing the gland (23) onto the upper surface of the bearing block (51).