CN2823744Y

CN2823744Y - Valve rod sealer and stop valve, gate valve and ball valve using same

Info

Publication number: CN2823744Y
Application number: CN 200520143150
Authority: CN
Inventors: 翁四川
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-07-15
Filing date: 2005-11-14
Publication date: 2006-10-04
Anticipated expiration: 2015-11-14

Abstract

The utility model provides a sealing device of a valve rod, and a stop valve, a gate valve and a ball valve, which use the sealing device. A valve rod of the sealing device is provided with a cross-shaped step shaft, and the upper part of the valve rod penetrates through a circular hole in a valve cap to extend outside the valve cap. The valve rod is in a clearance fit with the circular hole in the valve cap, the big end of the valve rod is positioned in the valve cap and a sealing ring is arranged between the valve cap and the big end of the valve rod. The upper end of the valve rod is fixed with a spacing block, a spring penetrating through the valve rod is arranged between the spacing block and the valve cap and the spring is in a compression state. The valve rod seal is end surface seal. Under the action of the spring force and the medium pressure, the valve rod is always towed by upward force, thereby, the contact surface of the sealing ring is always tightly contacted with the valve cap and the end surface of the valve rod. The sealing purpose is achieved. The reliable seal for the valve rod can be realized before the sealing ring is completely worn. The whole sealing device has the advantages of simple structure and high sealing reliability. The service lives of valves, such as a stop valve, a gate valve, a ball valve, etc., are extended.

Description

Stop valve, gate valve, the ball valve of valve rod sealing device and employing sealing device

Technical field

The present invention relates to a kind of valve rod sealing device of valve, and the gate valve, stop valve, the ball valve that adopt this seal arrangement.

Background technique

Axial seal is adopted in the sealing of valve rods such as existing gate valve, stop valve, ball valve mostly, promptly sealing surface valve rod axially on, come sealed valve stem by filling out with stuffing box packing in the packing groove between valve gap and valve rod.Chinese patent CN2648219Y discloses a kind of spring valve rod leak-proof structure, this structure comprises valve body, valve rod, valve gap, spring, sealing material, sealing material is a filler, valve body and valve rod axially between a packing groove is arranged, filler is arranged in the packing groove, valve rod and valve body are fixed with valve gap, be provided with spring in the packing groove, the end face of spring is connected with gland or filler, and the elastic reaction by spring makes filler be in compressive state, filler is expanded to both sides, to reach the purpose of sealing.

Adopt above-mentioned sealing configuration at valve opening or close and still can occur when reaching certain number of times leaking, this is because the valve stem seal section is the cylindrical body sealing surface, only depend between cylindrical body sealing surface and filler radial pressure to contact and realize sealing, in fact this radial pressure that produces by spring, in axial distribution is uneven, and it also is uneven that hoop distributes, because producing, filler leans on spring force effect extruding when wearing and tearing again, wearing and tearing with automatic compensation filler, but increase along with the filler wear extent, and the inertia of filler existence itself, therefore, even the radial pressure that has spring to provide, time has been grown and can not make filler and cylindrical body sealing surface keep closely contacting, thereby can not seal reliably, produce leakage, shorten the life-span of valve.

The model utility content

The utility model aims to provide a kind of seal arrangement reliable, that life of valve is long that seals.

Another purpose of the present utility model provides a kind of stop valve, gate valve, ball valve that adopts this seal arrangement.

The technological scheme that the utility model adopted is: a kind of valve rod sealing device, comprise valve rod, valve gap, spring, seal ring, one circular hole is arranged in the middle of the valve gap, the circular hole that valve rod top is passed in the valve gap stretches out outside the valve gap, circular hole in valve rod and the valve gap is a Spielpassung, it is characterized in that: described valve rod is the cross multidiameter shaft, its big end is positioned at valve gap, between valve gap and the big end of valve rod upper-end surface, be provided with seal ring, the valve rod upper end is fixed with limiting stopper, have spring to be located on the valve rod between limiting stopper and valve gap, spring is in compressive state.

Be provided with bearing between described spring lower end surface and the valve gap, bearing is located on the valve rod.

Described limiting stopper can be nut or snap ring.

Described valve gap circular hole is up-small and down-big shoulder hole, and macropore matches with the big end of valve rod, and aperture matches with the small end of valve rod.

A kind of stop valve, mainly comprise valve rod, valve gap, spool, valve body, handwheel, the circular hole that valve rod top is passed in the valve gap stretches out outside the valve gap, the top is fixedly connected with handwheel by nut, circular hole in valve rod and the valve gap is a Spielpassung, the lower end of valve rod is connected by pin with spool, valve gap is fixedlyed connected with valve body, it is characterized in that: the valve gap circular hole is up-small and down-big shoulder hole, valve rod is a segmented, upper valve rod is the cross multidiameter shaft, and its underpart is provided with a blind hole, and the hole inside fire attack has screw thread, the big end of upper valve rod is positioned at valve gap ladder macropore, be provided with seal ring between its big end upper-end surface and the valve gap, outside thread has been attacked on the top of lower valve rod, on, lower valve rod flexibly connects by screw thread; Respectively there is a guiding groove both sides at body cavity, respectively are fixedly connected with guide plate in the both sides of spool, and an end end of guide plate stretches out outside the spool, and can slide up and down along guiding groove; Have spring, bearing to be located on the upper valve rod between handwheel and valve gap successively, spring is in compressive state.

Described valve gap is a two-part, and the circular hole of upper and lower valve gap is up-small and down-big shoulder hole, and the diameter of the aperture of bottom flange is bigger than the diameter of bonnet macropore, and upper and lower valve gap is fixedly connected; Upper valve rod is a segmented, and the epimere of upper valve rod is the inverted T-shape axle, and its big end is positioned at bonnet ladder macropore, is provided with seal ring between the upper-end surface of big end and the valve gap, and big bottom portion is provided with blind hole; The hypomere of upper valve rod is the cross multidiameter shaft, its top is stretched in the blind hole of upper valve rod epimere, be connected with the upper valve rod epimere by pin, the big end of its multidiameter shaft is positioned at bottom flange ladder macropore, be provided with seal ring between big end upper-end surface and the bottom flange, the top of cross multidiameter shaft is fixed with limited ring, has spring, bearing to be located on the multidiameter shaft between limited ring and bottom flange successively, and spring is in compressive state.

Internal thread has been attacked in described stop valve bonnet bottom, and bottom flange is inverted T-shape, and outside thread has been attacked on its top, and upper and lower valve gap is fixedly connected by screw thread.

A kind of gate valve, mainly comprise valve rod, valve gap, flashboard, valve body, handwheel, one circular hole is arranged in the middle of the valve gap, the circular hole that valve rod top is passed in the valve gap stretches out outside the valve gap, the top is fixedly connected with handwheel by nut, circular hole in valve rod and the valve gap is a Spielpassung, the lower end and the flashboard of valve rod flexibly connect by screw thread, valve gap is fixedlyed connected with valve body by bolt, it is characterized in that: the valve gap circular hole is up-small and down-big shoulder hole, and valve rod is the cross multidiameter shaft, its big end is positioned at valve gap ladder macropore, be provided with seal ring between big end upper-end surface and the valve gap, spring is arranged between handwheel and the valve gap successively, bearing is located on the valve rod, and spring is in compressive state.

Described gate valve rod is a two-part, upper valve rod is the inverted T-shape axle, its underpart is provided with blind hole, the side is provided with manhole, its big end is positioned at bonnet ladder macropore, holds greatly between upper-end surface and the valve gap and is provided with seal ring, and the upper end of lower valve rod is stretched in the blind hole of upper valve rod, match with the shape of upper valve rod blind hole, be connected with upper valve rod by pin.

A kind of ball valve, mainly comprise valve gap, valve rod, valve body, spool, handle, valve gap and valve body are an integral body, one circular hole is arranged in the middle of the valve gap, valve rod is the cross multidiameter shaft, the circular hole that valve rod top is passed in the valve gap stretches out outside the valve gap, its top is fixedly connected with handwheel, and the circular hole in valve rod and the valve gap is a Spielpassung, and spool is positioned at valve body, the lower end of valve rod and spool flexibly connect, it is characterized in that: the circular hole of valve gap is up-small and down-big shoulder hole, and the big end of valve rod is positioned at valve gap, is provided with seal ring between its big end upper-end surface and the valve gap, spring is arranged between handwheel and the valve gap successively, bearing is located on the valve rod, and spring is in compressive state.

The present invention creatively changes valve rod sealing device into end face seal by axial seal, because the effect of spring force and pressure medium, make the surface of contact of seal ring remain tight the contact with valve gap, valve rod end face, reach the purpose of sealing, still can be before seal ring has worn and torn fully to the valve rod reliable sealing, whole sealing device is simple in structure, sealing reliability height, the working life of having improved valve greatly; Between spring and valve gap, be provided with bearing, when operating valve lever, make its operational torque littler, more laborsaving; The circular hole of valve gap is a shoulder hole, macropore matches with the big end of valve rod, and aperture matches with the valve rod small end, because the macropore in valve rod and the valve gap is a matching relationship, therefore the extended guiding length of valve rod can guarantee reliably more that valve rod can not produce swing or crooked phenomenon when operation.

Description of drawings

Fig. 1 is the structural representation of valve rod sealing device.

Fig. 2 is the structural representation of stop valve.

Fig. 3 is the structural representation of the another kind of structure of stop valve.

Fig. 4 is the structural representation of gate valve.

Fig. 5 is the structural representation of ball valve.

Fig. 6 is the axial partial sectional view of Fig. 2 and Fig. 3.

Embodiment

Embodiment 1, as shown in Figure 1, valve rod sealing device, mainly comprise: spring 4, valve rod 3, valve gap 7, seal ring 8, one circular hole is arranged in the middle of the valve gap 7, valve rod 3 is the cross multidiameter shaft, and valve rod 3 passes the circular hole in the valve gap 7, and stretches out outside the valve gap 7, circular hole in valve rod 3 and the valve gap 7 is a Spielpassung, its big end is positioned at valve gap 7, is equipped with two seal rings 8 between the upper-end surface of valve gap 7 and valve rod 3 big ends, and the external diameter of the external diameter of seal ring 8 and valve rod 3 big ends is suitable, be fixed with limited ring 1 in valve rod 3 upper ends, spring 4 is located on the valve rod 4, between limited ring 1 and valve gap 7, and makes spring 4 be in compressive state, because spring 4 is in compressive state, the power that valve rod 3 is made progress is mentioned, thereby makes two seal rings 8 and valve gap 7, valve rod 3 big end end faces closely contact, and reach the purpose of sealing.

Between spring 4 and valve gap 7, can also be equipped with bearing 5 on the valve rod 3; because the effect of bearing 5; eliminated the direct friction between spring 4 and the valve gap 7; guaranteed when operating valve lever, to have little operational torque; also spring 4 and valve gap 7 are played a protective role, be unlikely because friction causes destroying.

Limited ring 1 can be nut or snap ring, if when being nut, should correspondingly be provided with screw thread on valve rod 3, if when being snap ring, should correspondingly be provided with annular groove on valve rod 3.

The circular hole of valve gap 7 can be a shoulder hole, macropore matches with valve rod 3 big ends, aperture matches with valve rod 3 small ends, because the macropore in valve rod 3 and the valve gap 7 is a matching relationship, valve rod 3 guiding length have extended, therefore, can guarantee reliably that more valve rod 3 can not produce swing or crooked phenomenon when operation.

During work, medium flows to valve gap 7 under pressure, since the effect of seal ring 8 stoped medium from valve gap 7 circular hole and the gap between the upper valve rod 3 in leak, when valve opening or when closing, seal ring 8 can be because the rotation of valve rod 3, with the end face of valve rod 3 or and valve gap 7 or two seal rings 8 between friction mutually, along with valve opening or close the increase of number of times, cause seal ring 8 thickness wearing and tearing attenuate, but under the effect of spring 4 elastic force, the power that valve rod 3 is made progress is mentioned, the pressure of adding flowing medium acts on the end face of valve rod 3, make seal ring and valve gap, the valve rod end face remains tight contact, thereby has reached the purpose of sealing, has prevented the leakage of medium.

Embodiment 2, and as Fig. 2, shown in Figure 6, a kind of stop valve mainly comprises: valve rod 3, valve gap 7, spool 11, valve body 12, seal ring 8, handwheel 2.In the middle of the valve gap 7 circular hole, circular hole being arranged is up-small and down-big shoulder hole, and valve rod 3 is a two-part, i.e. upper valve rod 3A, lower valve rod 3B; Upper valve rod 3A is the cross multidiameter shaft, the circular hole in the valve gap 7 is passed on top, and stretch out outside the valve gap 7, its big end is positioned at valve gap 7 ladder macropores, with circular hole in the valve gap 7 be Spielpassung, attacked screw thread in upper end, limited ring 1 is a nut, by nut handwheel 2 is fixedly connected on the top of upper valve rod 3A, and the bottom of upper valve rod 3A is provided with a blind hole, the hole inside fire attack has screw thread, is provided with two seal rings 8 between its big end upper-end surface and valve gap 7; Lower valve rod 3B is cylindrical, outside thread has been attacked on top, the lower end is provided with annular groove, spool 11 is inverted T-shape, top is provided with blind hole, and its side is provided with a manhole, matches with spool 11 blind holes in lower valve rod 3B lower end, lower valve rod 3B is connected by driving pin 10 with spool 11, and the internal thread that screws into upper valve rod 3A of lower valve rod 3B is realized flexibly connecting; Valve gap 7 is fixedlyed connected with valve body 12 by bolt 6; Respectively be provided with a guiding groove 15 in the both sides of valve body 12 inner chambers, on spool 11 large end face both sides, respectively be fixedly connected with guide plate 9, guide plate 9 can be to be the font of falling Y, also can be that two big ends of Y word fuse, small end outwards is ring, guide plate 9 small ends stretch out outside the spool 11, and can slide up and down along guiding groove 15; Have spring 4, bearing 5 to be located on the upper valve rod 3A between handwheel 2 and valve gap 7 successively, spring 4 is in compressive state.

As shown in Figure 3, described stop valve, its valve gap 7 can be a two section type, be bonnet 7A, bottom flange 7B, bonnet 7A is cylindrical, the circular hole of upper and lower valve gap is up-small and down-big shoulder hole, and the diameter of the aperture of bottom flange is bigger than the diameter of bonnet macropore, and is fixedly connected between bonnet 7A, the bottom flange 7B; Spring 4 is provided with two, i.e. spring 4A, spring 4B, and seal ring 8 is provided with two covers, i.e. seal ring 8A, seal ring 8B, limited ring 1 is provided with two, and promptly limited ring 1A, limited ring 1B are nut; Valve rod 3 is a 3 stops, i.e. upper valve rod 3A, lower valve rod 3B, middle valve rod 3C; Upper valve rod 3A is the inverted T-shape axle, and the bottom is provided with tapered blind hole, and the side is provided with manhole, and its big end is positioned at bonnet 7A ladder macropore, holds greatly between upper-end surface and the bonnet 7A and is provided with seal ring 8A; Middle valve rod 3C is the cross multidiameter shaft, outside thread has been attacked on top, is fixed with limited ring 1 on the outside thread, and its top is taper, match with upper valve rod 3A tapered blind hole, the side is provided with the long-round-shape through hole, and its underpart is provided with blind hole, and the hole inside fire attack has screw thread, its big end is positioned at bottom flange 7B ladder macropore, be provided with two seal ring 8B between its big end upper-end surface and the bottom flange 7B, upper valve rod 3A is connected by pin 13 with middle valve rod 3C, and middle valve rod 3C, lower valve rod 3B flexibly connect by screw thread; Between limited ring 1B and bottom flange 7B, have successively spring 4B, bearing 5B be located on the valve rod 3C, spring is in compressive state; Limited ring 1A, upper valve rod 3A, spring 4A, bonnet 7A, seal ring 8A form a valve rod sealing device, limited ring 1B, middle valve rod 3C, spring 4B, bottom flange 7B, seal ring 8B form another valve rod sealing device, and promptly this stop valve has the effect of double seal.

During work, because the dual fail-safe effect of two

seals circle

8A, 8B is arranged, prevented the leakage of medium reliably, therefore, the stop valve of this structure is particularly suitable for being used on the pipeline of carrying inflammable, explosion hazard gases.

Fixedly connected between bonnet 7A, the bottom flange 7B, can be to adopt flange to connect, it is fixedly connected also can to adopt screw method to carry out, when adopting the latter, its fixed connection method is: attacked screw thread in bonnet 7A macropore bottom, bottom flange 7B is inverted T-shape, and the centre is big up and down, middle little shoulder hole, attacked outside thread on top, the internal thread by bonnet 7A screws in the outside thread of bottom flange 7B and realizes that the two is fixedly connected.

Embodiment 3, and as shown in Figure 4, a kind of gate valve mainly comprises: valve rod 3, valve gap 7, flashboard 14, valve body 12, handwheel 2.One up-small and down-big ladder circular hole is arranged in the middle of the valve gap 7, valve rod 3 is the cross multidiameter shaft, attacked outside thread on the top, outside thread has also been attacked in the lower end, the circular hole in the valve gap 7 is passed on top, and stretches out outside the valve gap 7, and its big end is positioned at macropore, with the circular hole in the valve gap 7 be Spielpassung, be provided with two seal rings 8 between valve rod 3 big end upper-end surfaces and the valve gap 7; Limited ring 1 is a nut, by nut handwheel 1 is fixedly connected on valve rod 3 afterbodys, is through hole in the middle of the flashboard 14, and the hole inside fire attack has screw thread, and valve rod 3 is realized flexibly connecting by screw thread with flashboard 14, and valve gap 7 achieves a fixed connection by bolt and valve body 12; Having spring 4, bearing 5 to be located on the valve rod 3 between handwheel 2 and the valve gap successively, spring 4 is in compressive state.

Valve gap 7 can be two section type, i.e. bonnet 7A, bottom flange 7B, and bonnet 7A is convex shape, the edge is provided with through hole, and bottom flange 7B is I-shaped, and interior is big up and down, middle little shoulder hole, top edge is provided with tapped hole, and bonnet 7A and bottom flange 7B achieve a fixed connection by bolt.

Valve rod 3 also can be two section type, be upper valve rod 3A, lower valve rod 3B, upper valve rod 3A is the inverted T-shape axle, be provided with conical blind hole in the bottom, the side is provided with manhole, its big end is positioned at valve gap 7 ladder macropores, be provided with two seal rings 8 between its big end upper-end surface and the valve gap, lower valve rod 3B is a T font axle, the upper end is conical matches with the conical blind hole of upper valve rod 3A, and the side is provided with the long-round-shape through hole, and upper valve rod 3A is connected by pin 13 with lower valve rod 3B, pin 13 is a transition fit with upper valve rod 3A manhole, and logical with lower valve rod 3B long-round-shape also is Spielpassung.

Embodiment 4, and as shown in Figure 5, a kind of ball valve mainly comprises: valve gap 7, valve rod 3, valve body 12, spool 11, handle 2.Valve gap 7 is an integral body with valve body 12, one manhole is arranged in the middle of the valve gap 7, valve rod 3 is the cross multidiameter shaft, pass the circular hole in the valve gap 7, and stretch out outside the valve gap 7, big end is positioned at valve gap 7, be provided with two seal rings 8 between its big end upper-end surface and the valve gap 7, attacked outside thread on the top, the lower end is long-round-shape, and limited ring 1 is a nut, handle 2 is fixedly connected on the valve rod 3 by this nut, circular hole in valve rod 3 and the valve gap 7 is a Spielpassung, and spool 11 is in the valve body 12, is provided with seal ring 14 between spool 11 and valve body 12, spool 11 tops are provided with groove, groove in the lower end of valve rod 3 and the spool 11 flexibly connects, and between handwheel 2 and valve gap 7 spring 4 is arranged successively, bearing 5 is located on the valve rod 3, and spring is in compressive state.

Claims

1, a kind of valve rod sealing device, comprise valve rod, valve gap, spring, seal ring, the circular hole that has a circular hole, valve rod top to pass in the valve gap in the middle of the valve gap stretches out outside the valve gap, and the circular hole in valve rod and the valve gap is a Spielpassung, it is characterized in that: described valve rod is the cross multidiameter shaft, its big end is positioned at valve gap, is provided with seal ring between valve gap and the big end of valve rod upper-end surface, and the valve rod upper end is fixed with limiting stopper, have spring to be located on the valve rod between limiting stopper and valve gap, spring is in compressive state.

2, valve rod sealing device according to claim 1 is characterized in that: be provided with bearing between described spring lower end surface and the valve gap, bearing is located on the valve rod.

3, valve rod sealing device according to claim 1 and 2 is characterized in that: described limiting stopper can be nut or snap ring.

4, valve rod sealing device according to claim 1 and 2 is characterized in that: described valve gap circular hole is up-small and down-big shoulder hole, and macropore matches with the big end of valve rod, and aperture matches with the small end of valve rod.

5, a kind of stop valve, mainly comprise valve rod, valve gap, spool, valve body, handwheel, the circular hole that valve rod top is passed in the valve gap stretches out outside the valve gap, the top is fixedly connected with handwheel by nut, circular hole in valve rod and the valve gap is a Spielpassung, the lower end of valve rod is connected by pin with spool, valve gap is fixedlyed connected with valve body, it is characterized in that: the valve gap circular hole is up-small and down-big shoulder hole, valve rod is a segmented, upper valve rod is the cross multidiameter shaft, and its underpart is provided with a blind hole, and the hole inside fire attack has screw thread, the big end of upper valve rod is positioned at valve gap ladder macropore, be provided with seal ring between its big end upper-end surface and the valve gap, outside thread has been attacked on the top of lower valve rod, on, lower valve rod flexibly connects by screw thread; Respectively there is a guiding groove both sides at body cavity, respectively are fixedly connected with guide plate in the both sides of spool, and an end end of guide plate stretches out outside the spool, and can slide up and down along guiding groove; Have spring, bearing to be located on the upper valve rod between handwheel and valve gap successively, spring is in compressive state.

6, stop valve according to claim 5 is characterized in that: described valve gap is a two-part, and the circular hole of upper and lower valve gap is up-small and down-big shoulder hole, and the diameter of the aperture of bottom flange is bigger than the diameter of bonnet macropore, and upper and lower valve gap is fixedly connected; Upper valve rod is a segmented, and the epimere of upper valve rod is the inverted T-shape axle, and its big end is positioned at bonnet ladder macropore, is provided with seal ring between the upper-end surface of big end and the valve gap, and big bottom portion is provided with blind hole; The hypomere of upper valve rod is the cross multidiameter shaft, its top is stretched in the blind hole of upper valve rod epimere, be connected with the upper valve rod epimere by pin, the big end of its multidiameter shaft is positioned at bottom flange ladder macropore, be provided with seal ring between big end upper-end surface and the bottom flange, the top of cross multidiameter shaft is fixed with limited ring, has spring, bearing to be located on the multidiameter shaft between limited ring and bottom flange successively, and spring is in compressive state.

7, stop valve according to claim 6 is characterized in that: internal thread has been attacked in described bonnet bottom, and bottom flange is inverted T-shape, and outside thread has been attacked on its top, and last bottom flange is fixedly connected by screw thread.

8, a kind of gate valve, mainly comprise valve rod, valve gap, flashboard, valve body, handwheel, one circular hole is arranged in the middle of the valve gap, the circular hole that valve rod top is passed in the valve gap stretches out outside the valve gap, the top is fixedly connected with handwheel by nut, circular hole in valve rod and the valve gap is a Spielpassung, the lower end and the flashboard of valve rod flexibly connect by screw thread, valve gap is fixedlyed connected with valve body by bolt, it is characterized in that: the valve gap circular hole is up-small and down-big shoulder hole, and valve rod is the cross multidiameter shaft, its big end is positioned at valve gap ladder macropore, be provided with seal ring between big end upper-end surface and the valve gap, spring is arranged between handwheel and the valve gap successively, bearing is located on the valve rod, and spring is in compressive state.

9, gate valve according to claim 8, it is characterized in that: described valve rod is a two-part, upper valve rod is the inverted T-shape axle, its underpart is provided with blind hole, and the side is provided with manhole, and its big end is positioned at bonnet ladder macropore, be provided with seal ring between big end upper-end surface and the valve gap, the upper end of lower valve rod is stretched in the blind hole of upper valve rod, matches with the shape of upper valve rod blind hole, is connected with upper valve rod by pin.

10, a kind of ball valve, mainly comprise valve gap, valve rod, valve body, spool, handle, valve gap and valve body are an integral body, one circular hole is arranged in the middle of the valve gap, valve rod is the cross multidiameter shaft, the circular hole that valve rod top is passed in the valve gap stretches out outside the valve gap, its top is fixedly connected with handwheel, and the circular hole in valve rod and the valve gap is a Spielpassung, and spool is positioned at valve body, the lower end of valve rod and spool flexibly connect, it is characterized in that: the circular hole of valve gap is up-small and down-big shoulder hole, and the big end of valve rod is positioned at valve gap, is provided with seal ring between its big end upper-end surface and the valve gap, spring is arranged between handwheel and the valve gap successively, bearing is located on the valve rod, and spring is in compressive state.