An adjustable limit butterfly valve with minimum flow capacity

Abstract

The adjustable limit butterfly valve with minimum flow capacity belongs to the technical field of valves, and aims to solve the problem of violent vibration of the butterfly plate when the butterfly valve is in a small flow opening state. The butterfly valve comprises two flow adjusting devices, the flow adjusting device comprises a speed reducer, a limiting rod and an adjusting cam, the limiting rod is arranged in the same direction with the valve rod, the limiting rod is in rotating sealing fit with the valve body, the speed reducer is fixed on the valve body, one end of the limiting rod is connected with the output end of the speed reducer, and the adjusting cam is sleeved on the limiting rod; the two limiting rods are respectively arranged in the two minimum valve closing adjusting areas, when the minimum flow capacity of the butterfly valve is adjusted, the actuator drives the butterfly plate to rotate to the valve closing position, and the outer periphery of the two adjusting cams respectively abuts against the butterfly plate. The two flow adjusting devices apply torque opposite to the valve closing force of the actuator to the butterfly plate, so that the butterfly plate is stable in force, and vibration of the butterfly plate can be avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of valves, and particularly relates to an adjustable limit butterfly valve with minimum flow capacity. BACKGROUND

[0002] The butterfly valve is a key product matched with the nuclear power conventional island and the steam turbine system of the thermal power. The butterfly valve is connected with the DCS control system, and can realize remote control of the computer program. When the steam turbine supplies heat or steam, the butterfly valve is in a small flow opening state, and when the unit normally generates power, the valve is quickly opened, so as to realize switching between the unit steam supply and the normal power generation condition.

[0003] When the unit supplies heat or steam, the butterfly valve is in a flow state under a small flow opening, at this time, the pressure difference before and after the valve is large, the valve opening is small, and vortex and turbulent flow are generated after the steam passes through the butterfly plate, which can cause severe vibration of the butterfly plate. When the valve is fully opened, the steam flow is large, and the vibration of the butterfly plate is also easy to occur. The existing butterfly valve usually adopts an actuator to limit the small opening. Since the butterfly plate is far away from the actuator, the vibration problem caused by the torsion and bending of the valve rod still exists. When the valve diameter is large and in a small flow opening state, the valve vibration problem is more obvious, and the valve vibration problem cannot be solved. The severe vibration of the valve can cause the vibration of the pipeline, which seriously threatens the normal operation of the unit. SUMMARY

[0004] The purpose of the present application is to provide an adjustable limit butterfly valve with minimum flow capacity, so as to solve the problem of severe vibration of the butterfly plate when the butterfly valve is in a small flow opening state. The technical scheme adopted by the present application is as follows:

[0005] An adjustable limit butterfly valve with minimum flow capacity, comprising a valve body and a butterfly plate, the butterfly plate being hinged on a medium passage of the valve body, one end of a valve rod being connected with an output end of an actuator, the other end of the valve rod penetrating downward through the valve body and being connected with the butterfly plate, the valve rod being in rotational sealing cooperation with the valve body, further comprising two flow adjusting devices, the flow adjusting device comprising a speed reducer, a limiting rod and an adjusting cam, the limiting rod being arranged in the same direction as the valve rod, the limiting rod being in rotational sealing cooperation with the valve body, the speed reducer being fixed on the valve body, one end of the limiting rod being connected with an output end of the speed reducer, and the adjusting cam being sleeved on the limiting rod.

[0006] The fan-shaped area in which the butterfly plate rotates left and right when the valve is opened is defined as a stroke range, the other side of the butterfly plate at the valve closing position opposite to the two stroke ranges is a minimum valve closing adjusting area, the two limiting rods are respectively arranged in the two minimum valve closing adjusting areas, when the minimum flow capacity of the butterfly valve is adjusted, the actuator drives the butterfly plate to rotate to the valve closing position, and the outer periphery of the two adjusting cams respectively abuts against the butterfly plate.

[0007] Further, a convex ring structure is arranged in the middle of the inner wall of the medium passage of the valve body, the inner diameter of the convex ring structure is larger than the outer diameter of the butterfly plate, when the valve is completely closed, the butterfly plate is sleeved with the convex ring structure, and a gap is formed between the convex ring structure and the butterfly plate.

[0008] Further, the butterfly plate is sleeved on the valve rod, and the butterfly plate and the valve rod are fixed by a plurality of pin shafts.

[0009] Further, the pin shaft is a conical pin, the small-diameter end of the pin shaft is threadedly connected with the pre-tightening nut, and the pin shaft and the pre-tightening nut are fixed by the cylindrical pin.

[0010] Further, the actuator is connected with the valve body through the support, the limiting inner sleeve and the limiting outer sleeve are sequentially sleeved on the valve rod from inside to outside, the limiting outer sleeve is connected with the support, the limiting inner sleeve is matched with the valve rod through the long key, the outer circumferential surface of the limiting inner sleeve is provided with a circular arc groove, the inner circumferential surface of the limiting outer sleeve is provided with an arc-shaped protrusion, the radius of the arc-shaped protrusion is matched with the radius of the circular arc groove, the arc degree of the circular arc groove is larger than the arc degree of the arc-shaped protrusion, when the circumferential one end of the arc-shaped protrusion is abutted with the circumferential one end of the circular arc groove, the butterfly valve is completely opened, and when the circumferential other end of the arc-shaped protrusion is abutted with the circumferential other end of the circular arc groove, the butterfly valve is in the closed position.

[0011] Further, the butterfly plate comprises a middle main body part and an edge ring part arranged inside and outside, the surfaces of the two ends of the middle main body part are convex spherical surfaces, and the surface of the edge ring part of the butterfly plate is subjected to hardening treatment.

[0012] Further, the upper side of the valve body is provided with a first stepped hole, the valve rod passes through the first stepped hole, the bottom of the first stepped hole is embedded with a first sliding bearing, the valve rod is rotationally matched with the first sliding bearing, the valve cover presses the packing on the upper end surface of the first sliding bearing, and the valve rod is rotationally and sealingly matched with the valve body through the packing.

[0013] Further, the lower side of the valve body is provided with a second stepped hole, the end cover seals the lower end of the second stepped hole, the second sliding bearing is embedded in the second stepped hole, and the valve rod is rotationally matched with the second sliding bearing.

[0014] Further, the inner hole and the end surface of the first sliding bearing are provided with a first wear-resistant layer, the inner hole and the end surface of the second sliding bearing are provided with a second wear-resistant layer, the surface of the valve rod is provided with a third wear-resistant layer and a fourth wear-resistant layer from top to bottom, the valve rod is rotationally matched with the first wear-resistant layer through the third wear-resistant layer, and the valve rod is rotationally matched with the second wear-resistant layer through the fourth wear-resistant layer.

[0015] Further, the bottom of the valve body is provided with a drain hole.

[0016] Compared with the prior art, the beneficial effects of the present application are that:

[0017] The present application drives the butterfly plate to rotate through the actuator, when the butterfly valve is at small flow opening, two flow adjusting devices exert torque on the butterfly plate opposite to the valve closing force of the actuator, so that the butterfly plate is stable, and the vibration of the butterfly plate can be avoided, since the outer periphery of the adjusting cam is an unequal radius curved surface, the minimum opening of the butterfly plate can be adjusted by rotating the limiting rod, and the acting point of the adjusting cam on the butterfly plate is located at both ends of the horizontal radial direction of the butterfly plate, so that the force arm of the force is large, and the torque adjustment is more beneficial. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of the present application;

[0019] Figure 2 is an A-A sectional view of Figure 1 ;

[0020] Figure 3 is a B-B sectional view of Figure 1 ;

[0021] Figure 4 is a C-C sectional view of Figure 1 when the minimum opening of the butterfly plate is adjusted;

[0022] Figure 5 is a C-C sectional view of Figure 1 when the valve is fully opened;

[0023] Figure 6 is an enlarged view of D of Figure 1 ;

[0024] Figure 7 is an enlarged view of E of Figure 1 .

[0025] In the figure, 1. valve body, 2. butterfly plate, 3. pin shaft, 4. pre-tightening nut, 5. cylindrical pin, 6. valve rod, 7. first sliding bearing, 8. support, 9. limiting outer sleeve, 10. limiting inner sleeve, 11. long key, 12. speed reducer motor, 13. limiting rod, 14. actuator, 15. adjusting cam, 16. convex ring structure, 17. end cover, 18. circular arc groove, 19. arc-shaped protrusion, 20. valve cover, 21. packing, 22. drain hole. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present application more clear and obvious, the present application is described below through specific embodiments shown in the drawings. However, it should be understood that these descriptions are only exemplary, and are not intended to limit the scope of the present application. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0027] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as bolted connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can be found to achieve this function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a bolted connection can be chosen for detachable connections.

[0028] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0029] Example: Figures 1-7 As shown, an adjustable limit butterfly valve with minimum flow capacity includes a valve body 1 and a butterfly plate 2. The butterfly plate 2 is hinged to the medium passage of the valve body 1. One end of the valve stem 6 is connected to the output end of the actuator 14, and the other end of the valve stem 6 passes downward through the valve body 1 and is connected to the butterfly plate 2. The valve stem 6 and the valve body 1 are rotatably sealed together. The valve body 1 also includes two flow regulating devices. The flow regulating devices include a reduction motor 12, a limit rod 13 and an adjusting cam 15. The limit rod 13 is arranged in the same direction as the valve stem 6 and is rotatably sealed together with the valve body 1. The reduction motor 12 is fixed on the valve body 1. One end of the limit rod 13 is connected to the output end of the reduction motor 12. The adjusting cam 15 is sleeved on the limit rod 13.

[0030] The fan-shaped area where the butterfly plate 2 rotates at both ends when the valve is opened is defined as the stroke range. The position where the butterfly plate 2 is transverse to the medium passage is the valve closing position. The other side of the valve closing position of the butterfly plate 2 opposite to the two stroke ranges is the minimum valve closing adjustment area. The two limit rods 13 are respectively set in the two minimum valve closing adjustment areas. When adjusting the minimum flow capacity of the butterfly valve, the actuator 14 drives the butterfly plate 2 to rotate towards the valve closing position, and the outer periphery of the two adjusting cams 15 abuts against the butterfly plate 2 respectively.

[0031] The present invention drives the butterfly plate 2 to rotate through the actuator 14. When the butterfly valve is at a small flow opening, the two flow regulating devices apply a torque to the butterfly plate 2 that is opposite to the valve closing force of the actuator 14, so that the butterfly plate 2 is stable and vibration of the butterfly plate 2 can be avoided. Since the outer periphery of the adjusting cam 15 is a curved surface with unequal radii, the minimum opening of the butterfly plate 2 can be adjusted by rotating the limit rod 13. The point of action of the adjusting cam 15 on the butterfly plate 2 is located at both ends of the horizontal radial direction of the butterfly plate 2. The lever arm of the force is large at this point, which is more conducive to torque adjustment.

[0032] The inner wall of the medium passage of the valve body 1 is provided with a convex ring structure 16, the inner diameter of the convex ring structure 16 is greater than the outer diameter of the butterfly plate 2, when the valve is completely closed, the butterfly plate 2 is sleeved with the convex ring structure 16, and a gap is formed between the convex ring structure 16 and the butterfly plate 2, so that the minimum steam flow requirement of the unit operation can still be met when the butterfly valve is completely closed.

[0033] The butterfly plate 2 is sleeved on the valve rod 6, and the butterfly plate 2 and the valve rod 6 are fixed by a plurality of pin shafts 3.

[0034] The pin shaft 3 is a conical pin, the small-diameter end of the pin shaft 3 is threadedly connected with the pre-tightening nut 4, and the pin shaft 3 and the pre-tightening nut 4 are fixed against retreat by the cylindrical pin 5, so that the pre-tightening nut 4 can be effectively prevented from loosening, and the stability and reliability of the whole connection are ensured.

[0035] The actuator 14 is connected with the valve body 1 through the support 8, the limiting inner sleeve 10 and the limiting outer sleeve 9 are sleeved on the valve rod 6 from inside to outside, the limiting outer sleeve 9 is connected with the support 8, the limiting inner sleeve 10 is matched with the valve rod 6 through the long key 11, the outer circumferential surface of the limiting inner sleeve 10 is provided with a circular arc groove 18, the inner circumferential surface of the limiting outer sleeve 9 is provided with an arc-shaped protrusion 19, the radius of the arc-shaped protrusion 19 is matched with the radius of the circular arc groove 18, the arc degree of the circular arc groove 18 is greater than the arc degree of the arc-shaped protrusion 19, when the circumferential one end of the arc-shaped protrusion 19 is abutted with the circumferential one end of the circular arc groove 18, the butterfly valve is completely opened, when the circumferential other end of the arc-shaped protrusion 19 is abutted with the circumferential other end of the circular arc groove 18, the butterfly valve is in the closed position, and in this way, the limiting in the fully open state of the valve can be realized, and it is ensured that the valve is not over opened.

[0036] The butterfly plate 2 comprises a middle main body part and an edge ring part arranged inside and outside, the surfaces of the two ends of the middle main body part are convex spherical surfaces, the butterfly plate 2 is designed as a double-convex spherical surface structure, the generation of vortexes behind the valve can be reduced, and the surface of the edge ring part of the butterfly plate 2 is subjected to hardening treatment to resist steam erosion.

[0037] The upper side of the valve body 1 is provided with a first stepped hole, the valve rod 6 passes through the first stepped hole, the bottom of the first stepped hole is embedded with a first sliding bearing 7, the valve rod 6 is rotationally matched with the first sliding bearing 7, the valve cover presses the packing 21 on the upper end surface of the first sliding bearing 7, and the valve rod 6 is rotationally and sealingly matched with the valve body 1 through the packing 21.

[0038] The lower side of the valve body 1 is provided with a second stepped hole, the lower end of the second stepped hole is sealed by an end cover, a second sliding bearing is embedded in the second stepped hole, and the valve rod 6 is rotationally matched with the second sliding bearing.

[0039] The inner hole and end face of the first sliding bearing 7 are provided with a first wear-resistant layer, the inner hole and end face of the second sliding bearing are provided with a second wear-resistant layer, the first wear-resistant layer and the second wear-resistant layer are formed by hardfacing hard alloy, the surface of the valve rod 6 is provided with a third wear-resistant layer and a fourth wear-resistant layer from top to bottom, the third wear-resistant layer and the fourth wear-resistant layer are formed by hardfacing hard alloy or by surface hardening treatment, the valve rod 6 is rotatably connected with the first wear-resistant layer through the third wear-resistant layer, and the valve rod 6 is rotatably connected with the second wear-resistant layer through the fourth wear-resistant layer, so as to improve wear resistance and prolong the overall service life of the butterfly valve.

[0040] The bottom of the valve body 1 is provided with a drain hole 22, and the drain hole 22 is connected with a drain pipe, so that when water is generated due to condensation of steam medium, the water can be discharged in time through the drain hole 22, and smooth operation of the valve is ensured.

[0041] The above examples are only illustrative of the present application and do not limit the protection scope thereof, and a person skilled in the art can also make changes to part of them, as long as the changes do not exceed the spirit and essence of the present application, and the changes are within the protection scope of the present application.

Claims

1. An adjustable limit butterfly valve with minimum flow capacity, comprising a valve body (1) and a butterfly plate (2), the butterfly plate (2) being hinged to the medium passage of the valve body (1), one end of a valve stem (6) being connected to the output end of an actuator (14), the other end of the valve stem (6) passing downward through the valve body (1) and connected to the butterfly plate (2), the valve stem (6) and the valve body (1) being in a rotational sealing fit, characterized in that: It also includes two flow regulating devices, each of which includes a speed reduction motor (12), a limit rod (13), and an adjusting cam (15). The limit rod (13) is set in the same direction as the valve stem (6), and the limit rod (13) is rotatably sealed to the valve body (1). The speed reduction motor (12) is fixed on the valve body (1), and one end of the limit rod (13) is connected to the output end of the speed reduction motor (12). The adjusting cam (15) is sleeved on the limit rod (13). The fan-shaped area on the left and right sides of the butterfly plate (2) when the valve is opened is defined as the stroke range. The other side of the butterfly plate (2) at the valve closing position opposite to the two stroke ranges is the minimum valve closing adjustment area. The two limit rods (13) are respectively set in the two minimum valve closing adjustment areas. When adjusting the minimum flow capacity of the butterfly valve, the actuator (14) drives the butterfly plate (2) to rotate towards the valve closing position, and the outer periphery of the two adjusting cams (15) abuts against the butterfly plate (2).

2. The adjustable limit butterfly valve with minimum flow capacity according to claim 1, characterized in that: A convex ring structure (16) is provided in the middle of the medium passage of the valve body (1). The inner diameter of the convex ring structure (16) is larger than the outer diameter of the butterfly plate (2). When the valve is fully closed, the butterfly plate (2) is sleeved with the convex ring structure (16), and a gap is formed between the convex ring structure (16) and the butterfly plate (2).

3. The adjustable limit butterfly valve with minimum flow capacity according to claim 1, characterized in that: The butterfly plate (2) is sleeved on the valve stem (6), and the butterfly plate (2) and the valve stem (6) are fixed by a number of pins (3).

4. The adjustable limit butterfly valve with minimum flow capacity according to claim 3, characterized in that: The pin (3) is a tapered pin. The small diameter end of the pin (3) is threaded to the preload nut (4). The pin (3) and the preload nut (4) are connected by a cylindrical pin (5) to prevent backlash.

5. An adjustable limit butterfly valve with minimum flow capacity according to claim 1, characterized in that: The actuator (14) is connected to the valve body (1) via the bracket (8). The inner limiting sleeve (10) and the outer limiting sleeve (9) are sequentially fitted onto the valve stem (6) from the inside to the outside. The outer limiting sleeve (9) is connected to the bracket (8). The inner limiting sleeve (10) and the valve stem (6) are engaged by a long key (11). The outer circumferential surface of the inner limiting sleeve (10) is provided with an arc groove (18), and the inner circumferential surface of the outer limiting sleeve (9) is provided with an arc protrusion. (19) The radius of the arc-shaped protrusion (19) is matched with the radius of the arc groove (18). The arc of the arc groove (18) is greater than the arc of the arc-shaped protrusion (19). When one circumferential end of the arc-shaped protrusion (19) abuts against one circumferential end of the arc groove (18), the butterfly valve is fully open. When the other circumferential end of the arc-shaped protrusion (19) abuts against the other circumferential end of the arc groove (18), the butterfly valve is in the closed position.

6. The adjustable limit butterfly valve with minimum flow capacity according to claim 1, characterized in that: The butterfly plate (2) includes a central main body and an edge ring, which are arranged inside and outside. Both ends of the central main body are convex spherical surfaces, and the surface of the edge ring of the butterfly plate (2) is hardened.

7. The adjustable limit butterfly valve with minimum flow capacity according to claim 1, characterized in that: The valve body (1) has a first stepped hole on its upper side. The valve stem (6) passes through the first stepped hole. A first sliding bearing (7) is embedded at the bottom of the first stepped hole. The valve stem (6) and the first sliding bearing (7) are rotatably engaged. The valve cover presses the packing (21) onto the upper end face of the first sliding bearing (7). The valve stem (6) is rotatably and sealed with the valve body (1) through the packing (21).

8. An adjustable limit butterfly valve with minimum flow capacity according to claim 7, characterized in that: The valve body (1) has a second stepped hole on its lower side. The end cap seals the lower end of the second stepped hole. A second sliding bearing is embedded in the second stepped hole. The valve stem (6) rotates with the second sliding bearing.

9. An adjustable limit butterfly valve with minimum flow capacity according to claim 8, characterized in that: The inner hole and end face of the first sliding bearing (7) are provided with a first wear-resistant layer, the inner hole and end face of the second sliding bearing are provided with a second wear-resistant layer, and the surface of the valve stem (6) is provided with a third wear-resistant layer and a fourth wear-resistant layer. The valve stem (6) is rotatably engaged with the first wear-resistant layer through the third wear-resistant layer, and the valve stem (6) is rotatably engaged with the second wear-resistant layer through the fourth wear-resistant layer.

10. An adjustable limit butterfly valve with minimum flow capacity according to any one of claims 1-9, characterized in that: A drainage hole (22) is provided at the bottom of the valve body (1).

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