CN107304845B - A bypass leak-free self-control return valve - Google Patents

Abstract

The invention belongs to a kind of automatic control return valves for bypassing No leakage, and in particular to a kind of bypass for being suitable for liquid medium can be carried out the automatic control return valve of sealing.Purpose is to solve the problems, such as to bypass to have the gap always in automatic control return valve application process to flow leakage, and valve body is the T-shaped structure of integral type threeway, is equipped with two main road, bypass valve chambers；Valve body upper end is equipped with support plate, and main road check-valves is equipped between valve body and support plate；Main road check-valves is positioned by guide rod swivel nut；Valve body is provided with pilot sleeve, and bypass valve seat is fixed on pilot sleeve, and valve head is connected with valve rod, and valve rod upper end is equipped with valve rod and adjusts head, adjusts the adjusting that head realizes bypass maximum stream flow by valve rod.The minimum discharge that the present invention is suitable for industrial centrifugal pump protects occasion; main, bypass changeover can be carried out automatically according to technique flow demand; and bypass maximum stream flow can carry out on-line control with the variation of technological parameter, the waste to avoid unnecessary recirculating mass to pump power.

Description

A bypass leak-free self-control return valve

technical field

The invention belongs to the technical field of self-control return valves, and in particular relates to a self-control return valve suitable for sealing a bypass of a liquid medium.

Background technique

A protection valve is installed at the pump outlet. When the pump is running in a large flow state, the main circuit check spool of the protection valve is opened, the bypass is closed, and the flow is all discharged from the main circuit outlet; when the pump is running in a small flow state, the main circuit check The valve core is closed, the bypass is opened, and all the flow is discharged from the bypass outlet. The main circuit and bypass can be switched with the change of process flow.

The existing pump protection valve is a three-way valve with a T-shaped structure. The lower part of the casing is provided with two valve cavities of the main circuit and the bypass, and is equipped with a bypass sleeve. A main circuit check valve core is installed between the guide rod screw sleeve and the bypass sleeve. There is a main circuit spring between the half shell and the main circuit check valve core. The lower part of the main circuit check valve core is a sleeve with a small hole. The movement of the main circuit check valve core drives the opening sleeve to move. So as to realize the main bypass switching. This type of pump protection valve has the following defects:

1) The cooperation between the main circuit check valve core sleeve and the bypass sleeve is a clearance fit, the main circuit fluid can enter the bypass through the gap, and there is always a gap flow problem in the bypass during use.

2) After the sleeve is drilled according to the given parameters, the bypass flow cannot be adjusted online according to the changes of pump parameters and process parameters.

3) The shell is divided into upper and lower parts, which needs to be sealed at the middle flange and compressed with fasteners. For severe working conditions such as high temperature, high pressure and low temperature, there is a risk of leakage of the middle flange, and maintenance of large-diameter valves is difficult.

4) The throttling surface of the main check valve core is on the valve body, resulting in uneven wall thickness of the valve body and greater difficulty in processing, thus prolonging the manufacturing cycle of the entire valve.

In view of the above problems existing in the technical solutions of the self-control return valve in the prior art, it is urgent to develop an automatic control return valve suitable for the bypass of liquid medium to be able to seal, so as to solve the above problems.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a self-controlled return valve suitable for the bypass of liquid medium to be sealed.

In order to realize this purpose, the technical scheme that the present invention takes is as follows:

A bypass leak-free self-control return valve, the valve body is a three-way T-shaped structure, the valve body is provided with a main circuit valve cavity connecting the main circuit inlet and the main circuit outlet, and a bypass connecting the main circuit inlet and the bypass outlet. Valve cavity; the upper end of the valve body is provided with a support plate, which is a clearance fit between the support plate and the valve body. The support plate is fixed to the main outlet of the valve body by a hexagon socket head screw and sealed with a gasket; the guide rod screw sleeve is installed through a clearance fit On the support plate, and fixed by one of the following methods: flange riveting, welding; the valve body is provided with a main circuit valve seat, and a main circuit check valve core is installed between the valve body and the support plate; the main circuit check valve The valve core is guided and hung on the main circuit valve seat by the clearance fit with the guide rod screw sleeve; the main circuit spring is installed in the upper cavity of the guide rod screw sleeve and the main circuit check valve core; the valve body is equipped with a guide sleeve to guide The sleeve and the valve body are in clearance fit, and are fixed in the bypass valve cavity of the valve body by the set screw, and the bypass valve seat is fixed on the guide sleeve; the bypass valve seat and the guide sleeve are in an interference fit, and the assembly is When the bypass valve seat is cold assembled into the guide sleeve, the matching gap is sealed by the sealing ring 1; after the valve stem and the bypass valve head are connected, they pass through the guide sleeve, and the upper end of the valve stem is connected with the valve stem adjustment head; The outer diameter of the valve stem adjustment head is larger than the inner diameter of the guide sleeve head, and the valve stem is suspended on the guide sleeve through the valve stem adjustment head; the length of the valve stem is adjusted through the valve stem adjustment head, so that the bypass is fully open. The throttling area of the valve seat changes, and the maximum bypass flow is adjusted within the range set by the system according to the changes of pump parameters and process parameters. The maximum flow of the bypass can be adjusted online with changes in process parameters.

Further, a bypass leak-free self-control return valve as described above, wherein: a multi-stage decompression orifice plate is installed between the valve body and the bypass valve body, and the bypass can withstand relatively high pressure through the multi-stage orifice plate decompression form. High bypass differential pressure, suitable for minimum flow protection occasions of higher lift pumps.

Further, a bypass leak-free self-control return valve as described above, wherein: the gap between the main road check valve core and the guide sleeve is sealed by the second sealing ring, and the second sealing ring is fixed by the retaining ring and the baffle. ; Realize the complete isolation of the main circuit valve cavity and the bypass valve cavity, and there is no gap leakage problem.

Further, the above-mentioned automatic control return valve with no leakage of bypass, wherein: the connection mode between the upper end of the valve stem and the valve stem adjustment head is one of the following modes: internal thread connection, external thread connection, Pin connection.

Further, a bypass leak-free self-control return valve as described above, wherein: the connection mode between the valve head and the valve stem of the bypass valve is one of the following modes: riveting, welding, pin connection; the above connection When the method is one of riveting and pin connection, the fitting gap between the valve head and the valve stem of the bypass valve is sealed with a sealing ring 1.

Further, a bypass leak-free self-control return valve as described above, wherein: the valve stem and the valve head of the bypass valve are not driven by mechanical coupling, and are driven entirely by the medium hydraulic power in the self-control return valve, and the liquid The power direction is always the opening direction of the main circuit, and the valve stem always has an unbalanced force in the opening direction of the main circuit during the valve operation.

Further, in the above-mentioned bypass leakage-free self-control return valve, wherein: the first and second regulating surfaces are arranged on the main circuit check valve, which reduces the processing difficulty of the regulating surfaces.

Further, a bypass leak-free self-control return valve as described above, wherein: the valve stem adjustment head and the main circuit check valve core are separated after the bypass is completely closed, and the bypass closure does not affect the main circuit stop. The further opening of the return valve core makes the pressure loss of the main circuit of the self-controlled return valve controlled within the allowable range of the process.

The beneficial effects of the present invention relative to the prior art are:

1. The present invention solves the problem that the original pump protection valve is difficult to achieve sealing by using clearance fit by adopting a new structure of the valve head and valve stem of the bypass valve driven by hydraulic power, and realizes that the bypass valve does not leak during the working process of the valve.

In addition, because the leakage problem of the bypass is solved, the main valve cavity and the bypass valve cavity inside the pump protection valve are completely separated to ensure the reliable operation of the valve stem.

2. The present invention adjusts the length of the valve stem through the valve stem adjustment head, and can adjust the throttling area of the bypass valve seat, so that the maximum flow rate of the bypass can be adjusted online within a certain range after the processing is completed. After the valve bypass is processed, the bypass maximum flow cannot be adjusted.

3. In the present invention, the throttling surface is placed on the check valve core of the main road, which reduces the difficulty of machining the shape.

4. The valve body of the present invention is one-piece, eliminating the need for middle flange seals and fasteners, reducing the risk of leakage of the middle flange, and the valve can be easily disassembled by loosening the screws of the support plate, which is convenient for maintenance.

5. The axial movement of the valve stem of the present invention is completely dependent on the hydraulic force provided by the medium, and the direction of the hydraulic force is always in the opening direction of the main circuit, so that the valve stem can move closely with the opening and closing of the main circuit check valve core, thereby ensuring accurate switching of the main bypass.

6. In the present invention, after the valve head of the bypass valve and the bypass valve seat are in contact, the hydraulic force is used as the sealing force, so that the bypass seal is reliable.

7. After the bypass is completely closed in the present invention, because the valve head of the bypass valve is hindered by the valve seat, the valve stem cannot rise with the continuous opening of the main circuit check valve core, and the valve stem adjustment head is separated from the main circuit check valve core. , the closing of the bypass will not affect the further opening of the main circuit check valve core, so that the main circuit pressure loss of the automatic control return valve can be controlled within the allowable range of the process when the normal process flow is running.

8. The connection form of the bypass outlet of the automatic control return valve in the present invention is flexible, and there are wire-planting, flange connection, and the bypass diameter can be designed according to the user's requirements. The bypass non-leakage automatic control return valve with flange in the bypass structure.

9. The bypass in the present invention can withstand a higher bypass pressure difference by applying a multi-stage orifice plate decompression form, so that it is also suitable for the minimum flow protection occasion of a higher head pump.

10. In the present invention, the shell of the automatic control return valve can be made into two forms of castings and forgings according to user requirements, so as to show great technical advantages in the case of non-standard design and tight construction period. The forging form shell is preferred to adopt one-piece structure. If the user has special requirements or the diameter is small, and the one-piece valve body is difficult to process, it can also be made into two-piece type, and the structure is flexible and changeable.

11. The connection forms of the valve stem and the valve head of the bypass valve in the present invention include welding, riveting, threaded connection and other forms, which can be selected according to the requirements of the working conditions.

12. In the present invention, the maximum flow rate of the bypass can be adjusted by changing the length of the valve stem through the valve stem adjustment head. As the length of the valve stem changes, the throttling area of the valve seat (section A-A in Figure 5) changes, so that the maximum flow rate of the bypass can be adjusted. change accordingly. The valve stem adjustment head has the form of thread (built-in or external) and the slotted pin connection with adjustable gear position. The larger the area, the larger the maximum bypass flow, and vice versa.

13. In the present invention, the bypass check valve can be built in and is not limited by the bypass structure.

Description of drawings

Fig. 1 Schematic diagram of the structure of the non-leakage self-control return valve of the bypass type in the form of planting;

Figure 2 is a schematic diagram of the bypass leak-free self-control return valve in the fully open state of the bypass;

Figure 3 is a schematic diagram of the bypass leak-free self-control return valve when switching states;

Figure 4 is a schematic diagram of the bypass leak-free self-control return valve in the fully open state of the main circuit;

Figure 5 is a schematic diagram of the maximum flow adjustment of the bypass;

Figure 6 is a schematic structural diagram of the bypass leakage-free self-control return valve of the bypass flange connection structure;

Figure 7 is a schematic diagram of the structure of the bypass non-leakage self-control return valve with the flange in the bypass;

Figure 8 is a schematic diagram of the structure of a bypass leak-free self-control return valve with a multi-stage decompression structure;

Figure 9 is a schematic structural diagram of the bypass leakage-free self-control return valve of the one-piece forging shell;

Figure 10 is a schematic diagram of the structure of the bypass leak-free self-control return valve of the two-piece forging shell;

Figure 11 Schematic diagram of the structure of the valve head of the valve stem bypass valve in the form of riveting;

Figure 12 Schematic diagram of the structure of the valve head of the valve stem bypass valve in welded form;

Figure 13 Schematic diagram of the structure of the valve head of the valve stem bypass valve in the form of pin connection;

Figure 14 Schematic diagram of the form of the inner thread valve stem adjustment head;

Figure 15 Schematic diagram of the form of the adjustment head of the external thread valve stem;

Figure 16 Schematic diagram of the form of the groove pin valve stem adjusting head;

Figure 17 Schematic diagram of the built-in bypass check structure of the non-leakage self-control return valve with bypass flange;

Fig. 18 Schematic diagram of the built-in bypass check structure of the leakage-free self-control return valve of the bypass flange connection structure.

In the figure: 1 valve body, 2 main circuit check valve core, 3 guide rod screw sleeve, 4 support plate, 5 main circuit spring, 6 guide sleeve, 7 bypass valve seat, 8 bypass valve head, 9 valve Rod, 10 sealing ring one, 11 set screw, 12 socket head cap screw, 13 sealing gasket, 14 sealing ring two, 15 baffle plate, 16 valve stem adjustment head, 17 retaining ring, 18 flange valve body with bypass outlet, 19 sealing ring three, 20 bypass valve body, 21 nut, 22 stud, 23 pressure relief orifice, 24 one-piece forged valve body, 25 control sleeve, 26 upper valve body, 27 lower valve body, 28 built-in control sleeve Pipe, 29 bypass check valve seat, 30 orifice plate, 31 bypass spring, 32 bypass bushing, 33 regulating surface one, 34 regulating surface two.

Detailed ways

Below in conjunction with accompanying drawing, a kind of bypass leak-free self-control return valve proposed by the present invention is further introduced:

As shown in Figure 1, an automatic control return valve with no bypass leakage. The valve body 1 is a three-way T-type structure. Bypass valve cavity with bypass outlet. The support plate 4 and the valve body 1 are in clearance fit, and are fixed at the main outlet of the valve body 1 with hexagon socket head screws 12 and sealed with a gasket 13 . The guide rod screw sleeve 3 is installed on the support plate 4 through clearance fit, and is fixed by flanging riveting or welding. The valve body 1 is provided with a main circuit valve seat, and the main circuit check valve core 2 is guided and suspended on the main circuit valve seat through the clearance fit with the guide rod screw sleeve 3 . A main circuit spring 5 is installed in the upper cavity of the guide rod screw sleeve 3 and the main circuit check valve core 2 . The guide sleeve 6 and the valve body 1 are in clearance fit, and are fixed in the bypass valve cavity of the valve body 1 by the set screw 11 . The gap between the lower cavity of the main road check valve core 2 and the guide sleeve 6 is sealed by the second sealing ring 14 (see Figures 11-13 ), and the second sealing ring 14 is fixed by the retaining ring 17 and the baffle 15 . The bypass valve seat 7 and the guide sleeve 6 are in an interference fit. During assembly, the bypass valve seat 7 is cold assembled into the guide sleeve 6 , and the matching gap is sealed by a sealing ring 10 . After the valve stem 9 and the valve head 8 of the bypass valve are connected, they pass through the guide sleeve 6, and the valve stem adjustment head 16 is connected with the inner thread (Fig. 11), the outer thread (Fig. 12) or the pin (Fig. 13). The outer diameter of the rod adjustment head 16 is larger than the inner diameter of the head of the guide sleeve 6 , so the valve rod can be suspended on the guide sleeve 6 through the valve rod adjustment head 16 . The valve head 8 and the valve stem 9 of the bypass valve can be connected by riveting (Fig. 14), welding (Fig. 15) and pinning (Fig. 16), etc. For riveting and pinning, the bypass valve head 8 The matching gap with the valve stem 9 needs to be sealed with a sealing ring 10.

In the above-mentioned automatic control return valve, wherein: the casing can be made into the form of castings and forgings according to user requirements. The forging form shell is preferably made of one-piece structure. If the user has special needs, it can also be made into two-piece structure, and its structure is flexible and changeable.

As shown in FIG. 14 , the gap between the main road check valve core 2 and the guide sleeve 6 is sealed by the second sealing ring 14 , and the second sealing ring 14 is fixed by the baffle 15 and the retaining ring 17 .

The valve stem 9 and the valve head 8 of the bypass valve are not driven by mechanical connection, and are completely driven by the hydraulic power of the medium in the automatic control return valve. Unbalanced force with main open direction. Before the pump is started, the hydraulic force acting on the valve stem 9 of the bypass valve head 8 is zero, the valve stem adjustment head 16 is separated from the main circuit check valve core 2, and the valve stem adjustment head 16 is separated from the main circuit check valve core 2 After the bypass is completely closed, it is separated and falls on the guide sleeve 6. It can be seen that the valve stem adjustment head 16 not only plays the role of adjusting the maximum flow of the bypass, but also prevents the valve stem 9 from falling out of the valve cavity when the pump is stopped. , the bypass closure does not affect the further opening of the main circuit check valve core 2, so that the pressure loss of the main circuit of the self-controlled return valve is controlled within the allowable range of the process.

As shown in Figure 2, after the pump is started, when the regulating valve downstream of the main outlet of the self-control return valve is closed, the flow through the regulating surface 1 33 and regulating surface 2 34 of the check valve core 2 of the main circuit is zero, acting on the main circuit. The hydraulic power on the check spool 2 is also zero, and the check spool 2 of the main circuit is pressed against the main circuit valve by the spring force of the main circuit (when the valve is installed vertically, there is also the effect of the gravity of the check spool 2 of the main circuit). On the seat, the opening of the check valve core of the main circuit (H in Figure 3 and Figure 4) is zero, the main channel of the valve is closed to ensure the sealing of the main circuit of the valve, and the valve head 8 of the bypass valve moves downward under the action of unbalanced force. Move in the bypass closing direction until the upper end of the valve stem adjustment head 16 bears against the lower cavity of the main circuit check valve core 2, at this time the bypass valve head 8 no longer moves in the bypass closing direction, the bypass flow reaches the maximum, and the valve state Fully open the main circuit for the bypass and close it completely. At this time, the main flow of the valve, that is, the flow required by the process, is zero, and the pump flow all flows back through the bypass valve seat through the bypass valve cavity, which corresponds to the recirculation condition of the pump.

When the on-site pump parameters and process parameters are changed, the maximum bypass flow can be adjusted by the valve stem adjustment head 16 within a certain range to adjust the length of the valve stem 9 to realize the throttling area of the bypass valve seat 7 (that is, the area of the section A-A in FIG. 5 ). ) adjustment, the maximum bypass flow adjustment principle for the internal and external thread adjusting head form is: by rotating the valve stem adjusting head 16 outwards, the length of the valve stem 9 is lengthened, so as to make the bypass valve seat 7 throttle area (ie. The area of section A-A in Figure 5) becomes larger, so that the maximum flow rate of the bypass becomes larger, and vice versa; for the groove pin adjustment head, the maximum flow adjustment principle of the bypass is as follows: the upper end of the valve stem 9 is opened with multi-stage grooves, and there are many There is an axial connection channel between the stage grooves, and the valve stem adjustment head 16 has a raised pin. When the valve stem adjustment head 16 moves to the outer stage groove and reaches the appropriate stage groove, it rotates along the radial direction of the valve stem. Lock, the length of the valve stem 9 becomes longer, and like the threaded valve stem adjustment head 16, the throttle area of the bypass valve seat 7 (that is, the area of the section A-A in Figure 5) becomes larger, so that the maximum bypass flow rate becomes larger, and vice versa become smaller, and realize on-line adjustment within a certain range of the maximum flow of the bypass of the self-controlled return valve.

As shown in Figure 3, the check valve core 2 of the main circuit of the automatic control return valve is balanced by the action of hydraulic force and spring force, and the hydraulic force is proportional to the flow rate and inversely proportional to the throttling area. The throttling surface is divided into upper and lower sections with different throttling areas, the upper section has a smaller throttling area, and the lower section has a larger throttling area. At the beginning of the opening of the downstream regulating valve of the main road outlet, with the sudden increase of the main road flow, because the throttling area of the main road check spool 2 is very small at this time, the hydraulic force is very large, and the main road check spool 2 is subjected to the spring When the force remains unchanged, the main circuit check valve core 2 is difficult to maintain balance, so it can only move in the direction of the hydrodynamic force, that is, the medium flow direction. The throttling area is small to ensure that the main circuit check spool 2 can be opened smoothly under the condition that the main circuit flow rate is small. The main circuit check valve core 2 corresponds to the opening degree H as shown in Figure 3. The head 8 and the valve stem 9 move to the bypass closing direction with the opening of the main circuit check spool 2 under the action of the unbalanced force. During this process, the valve stem adjusting head 16 and the main circuit check spool 2 are always kept in close contact with each other. . The flow rate of the main circuit is further increased, the main circuit check valve core 2 continues to open, and when the upper edge of the bypass valve head 8 is in contact with the conical surface of the bypass valve seat 7 (Fig. 4), the bypass opening is zero, and the bypass valve The valve head 8 and the valve stem 9 of the through valve no longer move, and the unbalanced force acting on the valve head 8 of the bypass valve acts as a hydraulic force to ensure the sealing of the bypass valve seat 7 . The adjusting head 16 is about to separate from the main circuit check valve core 2 . At this time, the process flow is greater than or equal to the minimum demand flow of the pump, the pump flow is all supplied to the process pipeline through the main circuit of the automatic control return valve, and the bypass return flow is zero, which corresponds to the critical operating condition of the main bypass switching of the automatic return valve.

As shown in Figure 4, the flow required by the process is further increased, and the opening of the downstream regulating valve at the main road outlet continues to increase. As in the situation described in Figure 3, when the throttle area of the main road check valve core 2 remains unchanged When the hydraulic power increases, the spring force on the check valve remains unchanged, and it is difficult for the main circuit check valve core 2 to maintain its balance, so it can only continue to move in the direction of the hydraulic power, that is, the medium flow direction, and the main circuit check valve core 2 continues to move. Up, the throttling section A-A is transferred to the regulating surface 2 34, and the throttling area is large, so that the main circuit spring can be compressed without compressing to generate enough spring force to balance the hydraulic power of the main circuit. When the check valve core is fully opened, the flow resistance of the main circuit is small, so that the pressure loss of the main circuit of the self-controlled return valve can be controlled within the allowable range of the process. However, the valve head 8 and the valve stem 9 of the bypass valve cannot rise together with the main circuit check valve core 2 due to the obstruction of the bypass valve seat 7, the bypass opening degree is still zero, and the main circuit check valve core 2 and the valve stem are adjusted The head 16 is separated, and as the flow of the process line reaches the set point (generally located near the rated flow point of the pump), the opening degree H of the main circuit check valve core also reaches the maximum. At this time, it corresponds to the fully open working condition of the main circuit of the automatic control return valve.

As shown in Figure 6, in the bypass flange connection structure of the bypass leakage-free automatic control return valve structure, the automatic control return valve shell, that is, the flange valve body 18 with the bypass outlet, is in the form of flange connection and is integrally cast. , in order to meet the connection requirements with the bypass pipeline.

As shown in Figure 7, in the structure of the bypass non-leakage self-control return valve with the bypass mid-flange, the valve body 1 is connected to the bypass valve body 20 through the nut 21 and the stud 22, and the end face is sealed with the sealing ring 3 19 to prevent Adapt to the diverse connection requirements of bypass pipe diameters.

The bypass can withstand a higher bypass pressure through the multi-stage orifice plate decompression form, making it also suitable for the minimum flow protection occasions of higher head pumps. As shown in Figure 8, a multi-stage decompression orifice 23 is installed between the valve body 1 and the bypass valve body 20 to reduce the pump outlet pressure to the back pressure, ensure the safety of pipeline equipment, and adapt to the minimum flow protection of the higher head pump .

The present invention is an automatic control return valve with no bypass leakage, and its casing can be made into castings and forgings according to user requirements, thereby showing great technical advantages under the condition of non-standard design and tight construction period. The forging form shell is preferably made of one-piece structure. If there are special requirements, it can also be made into two-piece type, and its structure is flexible and changeable.

As shown in Fig. 9, a bypass hole is opened on the one-piece forged valve body 24, and the bypass hole penetrates into the control sleeve 25. The control sleeve 25 and the one-piece forged valve body 24 are welded and fixed, and the guide sleeve must be ensured when fixing. After the cylinder 6 is installed, the coaxiality of the control sleeve 25 is provided with a bypass valve cavity, which ensures that the bypass of the self-controlled return valve has a return function. The advantage of this self-control return valve structure is that the shell is entirely forged or ready-made bar material is used, the production cycle is short, and the cost is low, especially when the construction period is tight and the non-standard design shows strong technical advantages.

As shown in Figure 10, in the bypass leak-free self-control return valve of the two-piece forging shell, the self-control return valve housing is composed of three parts: an upper valve body 26, a lower valve body 27, and a bypass valve body 20. The upper valve body 26 It is connected with the lower valve body 27 through the flange and fasteners in the main circuit, and is sealed by the sealing ring 319. The built-in control sleeve 28 is fixed on the lower valve body 27 by the bypass valve body 20, and is sealed by the Ring three 19 seals. It is especially suitable for small-diameter forging shells or occasions where the user requires a split forging shell.

The bypass main circuit check valve can be built in, and corresponding to different bypass structures, the bypass spring 21 can be limited in different ways. The connection form of the bypass outlet is flexible, there are wire-planting, flange connection, and the bypass diameter can be changed according to the user's requirements.

As shown in Figure 17, for the bypass non-leakage self-control return valve with the flange structure in the bypass, the built-in bypass check valve consists of the bypass check valve seat 29, the throttle orifice 30, and the bypass spring 31. It consists of three parts. When installing, it is necessary to install the bypass check parts first, then assemble the bypass valve body 20 and fasten the flange fasteners in the bypass. The right end of the bypass spring 31 is limited by the bypass valve body, which acts as a The non-return effect of preventing the medium from flowing back into the pump from the bypass pipeline.

As shown in Figure 18, for the bypass non-leakage self-control return valve without the bypass middle flange, the built-in bypass check valve parts are all loaded from the bypass outlet, and the valve body is provided with radial and axial grooves Slot, its built-in bypass check valve is composed of bypass check valve seat 29, orifice plate 30, bypass spring 31 and bypass bushing 32. The right end of bypass spring 31 is close to the bypass bushing. 32 is limited, the bypass bushing 32 is installed through the axial groove on the valve body and rotates and self-locks in the radial groove to prevent the bypass check valve from falling while playing the role of bypass check.

The invention is suitable for the minimum flow protection occasions of industrial centrifugal pumps, and can automatically switch between the main and bypass according to the process flow requirements of the main circuit, and completely close the bypass when the process flow exceeds the minimum demand flow of the pump, so as to avoid unnecessary reflows. The waste of the power of the circulating flow pump solves the problem that the existing self-controlled return valve cannot perform bypass sealing.

Claims (6)

1. a kind of automatic control return valve for bypassing No leakage, it is characterised in that:

Valve body (1) is three way type T-type structure, and main road valve chamber and connect master that connection main road import and main road export are equipped in valve body The bypass valve chamber of road import and bypass outlet；

The upper end of valve body (1) is equipped with support plate (4), is clearance fit between support plate (4) and valve body (1), and support plate (4) passes through Soket head cap screw (12) is fixed on valve body (1) main road and exports and be sealed with gasket (13)；

Guide rod swivel nut (3) is mounted on support plate (4) by clearance fit, and one of with the following methods fixed: flange riveting It connects, weld；

It is equipped with main road valve seat in valve body (1), main road non-return valve core (2) are installed between valve body (1) and support plate (4)；Main road Non-return valve core (2) with the clearance fit of guide rod swivel nut (3) by being oriented to and being suspended on main road valve seat；

Guide rod swivel nut (3) and the epicoele of main road non-return valve core (2) are provided with main road spring 5；

Valve body (1) is provided with pilot sleeve (6), and pilot sleeve (6) and valve body (1) are clearance fit, and pass through holding screw (11) bypass valve for being fixed on valve body (1) is intracavitary, and bypass valve seat (7) is fixed on pilot sleeve (6)；

Bypassing valve seat (7) and pilot sleeve (6) is interference fit, and bypass valve seat (7) cold charge is fitted on pilot sleeve (6) when assembly In, this fit clearance is sealed by sealing ring one (10)；

Pilot sleeve (6) are passed through after valve rod (9) and by-passing valve valve head (8) connection, the upper end of valve rod (9) and valve rod adjust head (16) it connects；

The outer diameter that valve rod adjusts head (16) is greater than the internal diameter on pilot sleeve (6) head, and valve rod (9) adjusts head (16) by valve rod and hangs It hangs on pilot sleeve (6)；

The length that head (16) regulating valve stem (9) are adjusted by valve rod makes to bypass the orifice size that valve seat (7) are bypassed under full-gear It changes, bypass maximum stream flow is adjusted in the range of default according to the variation of pump parameter and technological parameter；

Multi-step pressure reduction orifice plate (23) are installed between valve body (1) and bypass valve body (20)；

Main road non-return valve core (2) and the gap of pilot sleeve (6) are sealed by sealing ring two (14), and sealing ring two (14) is logical It crosses retaining ring (17) and baffle (15) is fixed；It realizes main road valve chamber and bypasses the completely isolated of valve chamber.

2. a kind of automatic control return valve for bypassing No leakage as described in claim 1, it is characterised in that: the upper end of valve rod (9) and It is one of following manner that valve rod, which adjusts the connection type between head (16): internal screw thread connection, external screw thread connection, pin connect It connects.

3. a kind of automatic control return valve for bypassing No leakage as described in claim 1, it is characterised in that: by-passing valve valve head (8) and Connection type between valve rod (9) is one of following manner: riveting, welding, pin connection；Above-mentioned connection type is riveting Connect, one of pin connection type when, the fit clearance of by-passing valve valve head (8) and valve rod (9) is carried out with sealing ring one (10) Sealing.

4. a kind of automatic control return valve for bypassing No leakage as described in claim 1, it is characterised in that: the valve rod (9), bypass Without mechanical attachment driving between valve valve head (8), the dielectric fluid power drive in automatic control return valve, hydraulic power direction are fully relied on Perseverance is main road opening direction, valve rod (9) permanent out-of-balance force with main road opening direction during valve working.

5. a kind of automatic control return valve for bypassing No leakage as described in claim 1, it is characterised in that: in main road non-return valve core (2) setting adjusts shape face one (33) and adjusts shape face two (34) on.

6. a kind of automatic control return valve for bypassing No leakage as described in claim 1, it is characterised in that: the valve rod adjusts head (16) separated after bypass completely closes with main road non-return valve core (2), bypass close do not influence main road non-return valve core (2) into One step is opened, and makes the control of automatic control return valve main road crushing in the range of technique allows.