CN204267742U - Control valve for small flows - Google Patents

Abstract

The utility model relates to a small flow control valve. The guide sleeve is installed in the valve cavity and placed on the spacer, the bush seat is installed in the inner hole of the guide sleeve and placed on the valve seat and pressed by the guide sleeve; the sealing soft bush is placed in the inner cavity of the bush seat, The center of the bushing seat and the sealing soft bushing is provided with a central through hole of the bushing assembly axially connected; Inside, the outer peripheral wall of the upper part of the spool is in sealing and sliding fit with the inner hole wall of the guide sleeve, and the outer wall of the lower part of the spool is in a sealing and sliding fit with the inner wall of the central through hole of the bushing assembly and the central hole of the valve seat; the outer wall of the lower part of the spool is provided with The V-shaped beveled groove runs along the length direction of the valve core, the V-shaped beveled groove has an oblique angle α in the length direction, and the V-shaped beveled groove has an included angle β in the cross-sectional direction. The utility model satisfies the requirements of on-site use well, solves the micro-flow adjustment, reduces the manufacturing cost, and improves the control precision.

Description

small flow control valve

technical field

The utility model relates to a small flow control valve, which belongs to the technical field of valve processing and manufacturing.

Background technique

For the small flow control valves used in the field of micro flow control valves, many domestic manufacturers mostly adopt the structure of the needle-shaped spool. The shape of the needle-shaped spool is corrected to meet the requirements of flow characteristics. The size of the spool is very small, only 1~2mm. Although the small flow valve structure of the needle spool can meet the requirements of the small flow valve, there will be some inherent disadvantages in the actual use process: the needle spool Easy to break, because the size is small, so it is easy to break in actual use, easy to wash, because the size is small, the flow rate of the fluid here is faster, it is easy to cause destructive washing to the needle valve core, and damage the needle Shaped spool, the adjustment accuracy is poor, because the curve of the needle spool is ground through the flow test data and the workers manually grind it out, resulting in differences every time, poor production stability, and unstable adjustment, poor precision, manufacturing The cost is high, because the correction of the small flow spool is done manually. Once the error is manually corrected, the spool will be remade, and in the process of correction, it will consume a lot of manpower and material resources, and it is difficult to meet the purpose of efficient production. .

In order to improve the domestic technical level of valves in this situation, and at the same time for our company to quickly enter this high-end field, our company has developed a small flow control valve through creative design, which completely eliminates the original problems and satisfies both The above working condition requirements prolong the service life of the valve.

Contents of the invention

The purpose of the utility model is to overcome the deficiencies in the prior art and provide a small flow control valve, which can well meet the requirements of on-site use through a novel structural design, fundamentally solve the small flow adjustment, and reduce the manufacturing cost. Cost, improve the control accuracy, not only meet the above use requirements, but also prolong the service life of the valve, save costs for domestic production enterprises and provide the necessary guarantee for continuous production.

According to the technical solution provided by the utility model: the small flow control valve includes a valve body, a valve cover, a valve core, a valve stem, a valve seat and a spacer, the valve body is provided with a valve cavity, and the valve seat is installed in the valve cavity. The valve seat is supported by steps in the valve cavity of the valve body, and the contact part between the valve seat and the valve body is in a sealed connection. The valve seat is provided with a center hole of the valve seat. In the valve cavity and placed on the valve seat, the bottom of the spacer is offset against the top of the valve seat, and several through holes are evenly arranged on the peripheral wall of the spacer; the valve stem passes through the valve cover, and the valve stem and the valve cover are sealed by sealing The structure is sealed, the lower end of the valve stem is connected to the valve core; the valve body is provided with a medium inlet and a medium outlet, the medium inlet is connected to the lower end of the valve seat installation hole, and the medium outlet is connected to the outer space of the valve seat and the spacer; it is characterized in that: The small flow control valve also includes a guide sleeve, a bush seat and a soft sealing bush, the guide sleeve is placed in the valve cavity and placed on the spacer, the bottom of the guide sleeve is against the top of the spacer; the bush seat is installed In the inner hole of the guide sleeve and placed on the valve seat, the edge of the bush seat is pressed by the lower end of the guide sleeve; the soft sealing bush is set in the inner cavity of the bush seat, and the center of the bush seat and the soft seal bush There is a central through hole of the bushing assembly connected axially; the valve core is movably assembled in the inner hole of the guide sleeve, the inner hole of the spacer, the central through hole of the bushing assembly and the central hole of the valve seat, and the outer peripheral wall of the upper part of the valve core The outer wall of the lower part of the valve core is sealed and slidingly matched with the inner wall of the central through hole of the bushing assembly and the inner wall of the center hole of the valve seat; the outer wall of the lower part of the valve core is provided with a The V-shaped beveled groove has a bevel angle α in the length direction, that is, the depth of the V-shaped beveled groove gradually increases from the upper end of the valve core to the lower end of the valve core, and the bottom line of the V-shaped beveled groove There is an included angle α with the central axis of the valve core; the V-shaped beveled groove has an included angle β in the cross-sectional direction, that is, there is an included angle β between the two inner sidewalls of the V-shaped beveled groove.

As a further improvement of the utility model, the soft sealing bush is made of polytetrafluoroethylene (PTFE).

As a further improvement of the utility model, the bottom surface of the valve seat is provided with a valve seat sealing ring groove, and a valve seat gasket is arranged in the valve seat sealing ring groove; the bottom surface of the valve cover is provided with a valve cover sealing ring groove. A valve cover gasket is arranged in the valve cover sealing ring groove.

As a further improvement of the utility model, both the valve seat gasket and the valve cover gasket are wound gaskets.

As a further improvement of the utility model, the sealing structure includes a packing gasket, a packing, a packing spacer, a packing gland and a packing gland; There is a packing spacer in the middle of the packing, and a packing gland above the packing. The packing gland is pressed by the packing gland arranged above it, and the packing gland and the valve cover are connected by a second fastening joint. Fixed connection.

As a further improvement of the utility model, the second fastening connector includes a second double-ended stud and a second hex nut, the lower end of the second double-ended stud is connected to the gland, and the second double-ended stud After the upper end of the column passes through the packing gland, the second hex nut is screwed.

As a further improvement of the utility model, an inner sealing ring groove is provided on the inner wall of the packing gland, and a first O-shaped sealing ring is installed in the inner sealing ring groove; an outer sealing ring groove is arranged on the outer wall of the packing gland, and the outer sealing ring groove A second O-ring seal is housed in the seal ring groove.

Compared with the prior art, the utility model has the following advantages: the utility model can well meet the requirements of on-site use through the novel structural design, fundamentally solve the micro-flow adjustment, reduce the manufacturing cost, and improve the control precision. It not only meets the above use requirements, but also prolongs the service life of the valve, saves costs for domestic production enterprises and provides a necessary guarantee for continuous production.

Description of drawings

Fig. 1 is the overall structure diagram of the small flow control valve of the embodiment of the utility model.

Fig. 2 is a schematic structural view of the valve core in Fig. 1 .

Fig. 3 is a view taken along direction B of Fig. 2 .

FIG. 4 is a schematic diagram of the enlarged structure of part A in FIG. 1 .

Description of reference signs: 1-valve body, 1a-medium inlet, 1b-medium outlet, 2-bonnet, 3-spool, 3a-V-shaped beveled groove, 4-valve stem, 5-valve seat, 6- Spacer, 7-guide sleeve, 8-first stud, 9-first hex nut, 10-packing spacer, 11-packing gasket, 12-packing, 13-packing gland, 14-packing Gland, 15-second stud, 16-seat gasket, 17-second hex nut, 18-first O-ring, 19-second O-ring, 20-bonnet gasket, 21-bush seat, 22-seal soft bushing.

Detailed ways

Below in conjunction with specific accompanying drawing and embodiment the utility model is further described.

As shown in the figure: the small flow control valve in the embodiment is mainly composed of a valve body 1, a valve cover 2, a valve core 3, a valve stem 4, a valve seat 5, a spacer 6, a guide sleeve 7, and a first stud 8 , the first hex nut 9, the packing spacer 10, the packing liner 11, the packing 12, the packing gland 13, the packing gland 14, the second stud 15, the valve seat washer 16, the second hex nut 17 , The first O-ring 18, the second O-ring 19, the valve cover gasket 20, the bush seat 21 and the soft sealing bush 22 and so on.

As shown in Figures 1 to 4, the valve body 1 is provided with a valve cavity, the valve seat 5 is installed in the valve cavity, the valve seat 5 is supported by steps in the valve cavity of the valve body 1, and the valve seat 5 and the valve body 1 The contact parts are sealed and connected, the valve seat 5 is provided with a center hole of the valve seat 5, and the valve cover 2 is fixed and sealed on the top of the valve body 1; the spacer 6 is installed in the valve cavity and placed on the valve seat 5 , the bottom of the spacer 6 is offset against the top of the valve seat 5, and several through holes are uniformly arranged on the wall of the spacer 6; the valve stem 4 passes through the valve cover 2, and the valve stem 4 and the valve cover 2 are sealed by a sealing structure, The lower end of the valve stem 4 is connected to the valve core 3; the valve body 1 is provided with a medium inlet 1a and a medium outlet 1b, the medium inlet 1a is connected to the lower end of the valve seat 5 installation hole, and the medium inlet 1a is connected to the valve seat 5 and the outside of the spacer 6 The space is connected; the guide sleeve 7 is installed in the valve cavity and placed on the spacer 6, and the bottom of the guide sleeve 7 is against the top of the spacer 6; the bush seat 21 is installed in the inner hole of the guide sleeve 7 and placed on the On the valve seat 5, the edge of the bush seat 21 is pressed by the lower end of the guide sleeve 7; Axially through the central through hole of the bushing assembly; the valve core 3 is movably assembled in the inner hole of the guide sleeve 7, the inner hole of the spacer 6, the central through hole of the bushing assembly and the central hole of the valve seat 5, the upper part of the valve core 3 The outer peripheral wall of the guide sleeve 7 is in sealing and sliding fit with the inner hole wall of the guide sleeve 7, and the outer wall of the spool 3 bottom is in a sealing and sliding fit with the central through hole of the bushing assembly and the inner wall of the center hole of the valve seat 5; There is a V-shaped beveled groove 3a running along the length direction of the valve core 3, and the V-shaped beveled groove 3a has an oblique angle α in the length direction, that is, the depth of the V-shaped beveled groove 3a is from the upper end of the valve core 3 to the valve core 3 The lower end gradually becomes larger, and the groove bottom line of the V-shaped beveled groove 3a has an included angle α with the central axis of the valve core 3; the V-shaped beveled groove 3a has an included angle β in the cross-sectional direction, that is, the V-shaped beveled groove 3a There is an included angle β between the two inner side walls.

The previous technical point of view believed that, for small flow control valves, in order to avoid some disadvantages caused by the needle spool 3, it was considered necessary to increase the size of the spool 3, but increasing the size of the spool 3 would inevitably lead to It is difficult to meet the problem of small flow regulation. The utility model adopts a novel structural design, that is, by processing the V-shaped beveled groove 3a on the surface of the valve core 3, the bevel angle α in the length direction of the V-shaped beveled groove 3a and the included angle β in the cross-sectional direction are used to determine the Control minimum flow. That is, the size of the included angle between the length direction of the V-shaped beveled groove 3a and the cross-sectional direction should be designed according to the flow coefficient [Cv value] of the minimum flow rate of the valve core 3.

As can be seen from Fig. 2 and Fig. 3, the kerf area of the V-shaped beveled groove 3a on the spool 3 is determined by the length L of the V-shaped beveled groove 3a, the diameter D of the spool 3 bottom, the V-shaped beveled groove The bevel angle α in the length direction of 3a and the included angle β in the cross-sectional direction of the V-shaped beveled groove 3a are determined by four parameters. Through these four parameters, different Cv values can be designed, and the size of the diameter D can also be increased, so that It can effectively avoid the situation that the needle valve core 3 is easy to break in China. The above four parameters only need to guarantee the processing accuracy, and the ordinary processing technology can meet the requirements, which greatly saves the production cost. All the valve cores 3 only need this If the four parameters are consistent, it can be interchangeable, can realize rapid replacement, is easy to maintain and has a long service life, and greatly reduces manpower, material resources, and financial resources.

Since the V-shaped beveled groove 3a is designed on the spool 3, the sealing problem between the spool 3 and the valve seat 5 is caused. The utility model designs a soft sealing bush 22 to realize the sealing of this part. It can be seen from Fig. 3 that the soft sealing bush 22 is tightly fitted in the bush seat 21, and the bush seat 21 is tightly pressed on the valve seat 5 by the spacer 6, and the outer periphery of the valve core 3 is sealed by the soft bush. 22 hugs, controls the diameter and the length of soft sealing bush 22, and spool 3 will be hugged tightly by soft sealing bush 22. The more the soft sealing bush 22 is compressed, the tighter the valve core 3 will be hugged, but the compression of the soft sealing bush 22 must be well controlled, otherwise there will be a locking situation, which will bring great inconvenience to subsequent debugging , or fail to debug at all. When the sealing soft bushing 22 holds the valve core 3 tightly, the medium can only flow out through the V-shaped beveled groove 3a of the valve core 3, which effectively prevents the medium from flowing out from the gap between the valve core 3 and the valve seat 5, thereby realizing small purpose of flow regulation. And because the sealing surface of the spool 3 is a metal seal, the erosion resistance of the medium is greatly improved. In the present utility model, the soft sealing bush 22 is preferably made of polytetrafluoroethylene [PTFE].

For the utility model, the calculation of the flow coefficient [Cv value] of the valve core 3 is also very important. The utility model estimates a flow coefficient first, then designs the V-shaped beveled groove 3a according to the flow coefficient, and finally passes the flow rate The results obtained from the test are used to calculate the actual flow coefficient, and according to the new flow coefficient, the V-shaped oblique groove 3a that meets the requirements can be designed on the new spool 3 . By analogy, other small-flow spools 3 with different Cv values can also be designed, and there is no problem even if the flow test is no longer performed. In this way, the rules can be found out through experiments, and a complete set of Cv value calculation procedures can be obtained. Different Cv values can be designed according to actual working conditions to meet the requirements of field use.

As shown in Figure 1, the bonnet 2 and the valve body 1 are fixedly connected by a fastening connection between the first stud 8 and the first hex nut 9, and the lower end of the first stud 8 is threaded. Connected to the valve body 1, the upper end of the first double-ended stud 8 passes through the valve cover 2 and then the first hex nut 9 is screwed.

As shown in Figures 1 and 3, the bottom surface of the valve seat 5 is provided with a valve seat 5 sealing ring groove, and a valve seat gasket 16 is arranged in the valve seat 5 sealing ring groove; the bottom surface of the valve cover 2 is provided with a valve cover 2 a sealing ring groove, a valve cover gasket 20 is arranged in the sealing ring groove of the valve cover 2; this can ensure better sealing performance between the valve seat 5, the valve cover 2 and the valve body 1. The valve seat gasket 16 and the valve cover gasket 20 are preferably wound gaskets.

As shown in Figures 1 and 3, in the present utility model, the sealing structure is mainly composed of packing liner 11, packing 12, packing spacer 106, packing gland 13 and packing gland 14. The outer circumference of the valve stem 4 is provided with a packing 12, a packing gasket 11 is provided below the packing 12, a packing spacer 106 is provided in the middle of the packing 12, and a packing gland 13 is provided above the packing 12, and the packing gland 13 passes through the The packing gland 14 is pressed, and the packing gland 14 is fixedly connected to the valve cover 2 through a second fastening member. The second fastening connector is mainly composed of a second double-ended stud 15 and a second hex nut 17, the lower end of the second double-ended stud 15 is connected to the gland, and the upper end of the second double-ended stud 15 After passing through the packing gland 14, the second hex nut 17 is screwed.

As shown in Figure 1, in the utility model, an inner sealing ring groove is provided on the inner wall of the packing gland 13, and a first O-shaped sealing ring 18 is housed in the inner sealing ring groove; The outer sealing ring groove, the second O-ring 19 is housed in the outer sealing ring groove. The first O-ring 18 is used to improve the sealing between the packing gland 13 and the valve stem 4, and the second O-ring 19 is used to improve the sealing between the packing gland 13 and the valve cover 2 sex.

Working principle and working process of the present utility model are as follows:

In specific applications, the medium flows in from the medium inlet 1a and directly enters under the valve seat 5. If the valve core 3 is in the open position, the upper end of the V-shaped beveled groove 3a on the valve core 3 is higher than the upper end of the central through hole of the bushing assembly. The medium will flow into the spacer 6 through the V-shaped beveled groove 3a on the valve core 3, and then flow through the through hole on the spacer 6 to the medium outlet 1b and out. If the valve core 3 is in the closed position, the upper end of the V-shaped chamfered groove 3a on the valve core 3 is lower than the upper end of the central through hole of the bush assembly, and the medium will exert pressure on the soft sealing bush 22 when it flows into the V-shaped chamfered groove 3a , so that the soft sealing bush 22 is compressed, and the soft sealing bush 22 will hold the spool 3 tightly when the soft sealing bush 22 is compressed, thus ensuring the tightness.

Claims (7)

1. Small flow control valve, including valve body (1), valve cover (2), valve core (3), valve stem (4), valve seat (5) and spacer (6), the valve body (1 ) is provided with a valve cavity, the valve seat (5) is installed in the valve cavity, the valve seat (5) is supported by the steps in the valve cavity of the valve body (1), and the contact part between the valve seat (5) and the valve body (1) Sealed connection, the valve seat (5) is provided with a center hole of the valve seat (5), the valve cover (2) is fixed and sealed on the top of the valve body (1); the spacer (6) is installed in the valve cavity And placed on the valve seat (5), the bottom of the spacer (6) is against the top of the valve seat (5), and several through holes are uniformly arranged on the surrounding wall of the spacer (6); the valve stem (4) passes through the valve The cover (2), the valve stem (4) and the valve cover (2) are sealed by a sealing structure, and the lower end of the valve stem (4) is connected to the valve core (3); the valve body (1) is provided with a medium inlet ( 1a) and the medium outlet (1b), the medium inlet (1a) communicates with the lower end of the installation hole of the valve seat (5), and the medium outlet (1b) communicates with the outer space of the valve seat (5) and the spacer (6); it is characterized in that: The small flow control valve also includes a guide sleeve (7), a bush seat (21) and a soft sealing bush (22), the guide sleeve (7) is installed in the valve cavity and placed on the spacer (6) , the bottom of the guide sleeve (7) is against the top of the spacer sleeve (6); the bush seat (21) is installed in the inner hole of the guide sleeve (7) and placed on the valve seat (5), the bush seat (21 ) edge is pressed by the lower end of the guide sleeve (7); the soft sealing bush (22) is installed in the inner cavity of the bushing seat (21), and the center of the bushing seat (21) and the soft sealing bushing (22) There is a central through hole of the bushing assembly axially connected; the valve core (3) is movably assembled in the inner hole of the guide sleeve (7), the inner hole of the spacer sleeve (6), the central through hole of the bushing assembly and the valve seat ( 5) In the central hole, the outer peripheral wall of the upper part of the valve core (3) is in sealing and sliding fit with the inner hole wall of the guide sleeve (7), and the outer wall of the lower part of the valve core (3) is in contact with the central through hole of the bushing assembly and the valve seat (5) The inner wall of the center hole is sealed and slidingly fitted; the outer wall of the lower part of the valve core (3) is provided with a V-shaped beveled groove (3a) running along the length direction of the valve core (3), and the V-shaped beveled groove (3a) There is a bevel angle α in the length direction, that is, the depth of the V-shaped beveled groove (3a) gradually increases from the upper end of the valve core (3) to the lower end of the valve core (3), and the groove bottom line of the V-shaped beveled groove (3a) is in line with the valve The central axis of the core (3) has an included angle α; the V-shaped beveled groove (3a) has an included angle β in the cross-sectional direction, that is, the two inner sidewalls of the V-shaped beveled groove (3a) have an included angle β . 2. The small flow control valve according to claim 1, characterized in that: the soft sealing bush (22) is made of polytetrafluoroethylene (PTFE). 3. The small flow control valve according to claim 1, characterized in that: the bottom surface of the valve seat (5) is provided with a sealing ring groove of the valve seat (5), and in the sealing ring groove of the valve seat (5) is provided Valve seat gasket (16); the bottom surface of the valve cover (2) is provided with a valve cover (2) sealing ring groove, and a valve cover gasket (20) is arranged in the valve cover (2) sealing ring groove. 4. The small flow control valve according to claim 3, characterized in that: the valve seat gasket (16) and the valve cover gasket (20) are both wound gaskets. 5. The small flow control valve according to claim 1, characterized in that: the sealing structure includes packing liner (11), packing (12), packing spacer (10) (6), packing gland (13 ) and packing gland (14), the valve stem (4) in the bonnet (2) is provided with a packing (12) on the outer periphery, and a packing liner (11) is provided under the packing (12), and the middle of the packing (12) A packing spacer (10) (6), a packing gland (13) is provided above the packing (12), and the packing gland (13) is pressed by the packing gland (14) arranged above it, and the packing The gland (14) is fixedly connected to the valve cover (2) through a second fastening piece. 6. The small flow control valve according to claim 5, characterized in that: the second fastening member comprises a second stud (15) and a second hex nut (17), the second The lower end of the stud (15) is connected to the gland, and the upper end of the second stud (15) passes through the packing gland (14) and then the second hex nut (17) is screwed. 7. The small flow control valve according to claim 5, characterized in that: the inner wall of the packing gland (13) is provided with an inner sealing ring groove, and a first O-ring (18) is installed in the inner sealing ring groove ; The outer wall of the packing gland (13) is provided with an outer seal ring groove, and a second O-ring seal (19) is installed in the outer seal ring groove.