A mechanical damping device for butterfly valve to resist water flow vibration

Abstract

The present invention relates to a mechanical damping device for a butterfly valve to resist water flow vibration, which is installed at the lower end surface of the butterfly valve body. The device comprises a base box with an opening downward, a cover plate fixed at the opening of the base box by bolts, a cam rotatable with the valve disc shaft and installed in a circular hole of the base box, a push rod which rotates with the cam to produce lateral movement, and a disc spring which is compressed and produces a reaction force in cooperation with the lateral movement of the push rod. Compared with the prior art, the present invention has the advantages of eliminating all swing vibrations caused by transmission matching clearances, good sealing, greatly prolonged service life, simple construction and easy manufacturing.

Description

Technical Field

[0001] The invention relates to the field of valve structures, in particular to a mechanical damping device for butterfly valves to resist water flow vibration. Background Art

[0002] Butterfly valves are one of the most widely used valves, especially in the waterway field. There are industry and international regulations on the water flow velocity resistance of butterfly valves, which generally shall not exceed 3-5m / s (this value is far from being achieved when installed at the water pump outlet). If this flow velocity is exceeded, the swing of the butterfly valve disc caused by the turbulent flow of the medium will be further aggravated, causing fatigue deformation of the pins and keys, loosening or even breaking of the brackets and bolts, and increasing the gap between the worm gears, ultimately greatly reducing the expected life of the butterfly valve.

[0003] In order to reduce the slight swing of the butterfly valve disc under water flow disturbance, valve manufacturers now have many design improvement plans. Some of them increase the friction between the shaft and the shaft seal, which can reduce the valve disc swing to a certain extent, but it brings undesirable phenomena such as shaft seal wear and increases the butterfly valve opening and closing torque to a certain extent. There are also methods such as reducing the mechanical matching clearance and setting the electric torque trip in the fully open state to eliminate the worm gear clearance to overcome the valve disc swing. These methods will not only make the valve manufacturing more difficult, but also fail to eliminate the clearance of the pin in the valve, and greatly reduce the life of the electric device. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a mechanical damping device for butterfly valves to resist water flow vibration.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A mechanical damping device for a butterfly valve to resist water flow vibration is installed at the lower end surface of the butterfly valve body. The device includes a base box with a downward opening, a cover plate fixed at the opening of the base box by bolts, a cam rotatable with the valve disc shaft and installed in a circular hole of the base box, a push rod that rotates with the cam to produce lateral movement, and a disc spring that is compressed to produce a reaction force in cooperation with the lateral movement of the push rod.

[0007] The cam is cylindrical, the top surface of the first cylinder with a larger radius contacts the bottom surface of the valve disc shaft and rotates with the valve disc shaft, and two protrusions are arranged at intervals of 180 degrees on the outer surface of the second cylinder with a smaller radius.

[0008] A second O-type sealing ring is arranged between the outer edge of the first-stage cylinder and the inner wall of the circular hole of the base box to prevent the leakage caused by the leakage of the lower shaft from penetrating into the base box.

[0009] The push rod has a square cross-section and can be installed in a straight groove of the base box in a linearly slidable manner. A clamping portion that cooperates with the protrusion is provided in the middle recessed portion of the push rod, and one end of the disc spring is in pressure contact with the inner end surface of the straight groove, and the other end is in contact with the inner end surface of the push rod. When the cam rotates, the protrusion contacts the clamping portion and drives the push rod to move inward laterally to compress the disc spring and generate a reaction force.

[0010] The device also includes a disc spring adjusting rod, the inner end of which contacts the outer end surface of the push rod, and the outer end extends out of the side of the base box to adjust the compression amount of the disc spring through a nut.

[0011] The number of the straight grooves and push rods is the same as the number of the protrusions, both of which are two. The number of disc springs corresponding to each push rod is set to one or more according to the actual requirements of the compression amount and the damping torque.

[0012] The device also includes a valve shaft adjusting rod, the head of which passes through the center holes of the cover plate and the cam in sequence and contacts the bottom surface of the valve disc shaft, and the tail is provided with an adjusting nut for adjusting the axial concentricity of the valve disc.

[0013] A third O-type sealing ring is arranged between the valve shaft adjusting rod and the central hole of the cam to prevent water from seeping out of the valve shaft.

[0014] The top surface of the base box is rigidly connected to the lower end surface of the butterfly valve body through a plurality of bolts, and a first O-type sealing ring is arranged on the contact surface to prevent axial leakage.

[0015] The working principle of the device is as follows:

[0016] When the butterfly valve opens to a set angle, the cam rotates to a set angle along with the valve disc shaft. At this time, the protrusion on the cam contacts the matching clamping part on the push rod and generates a lateral thrust. The push rod compresses the disc spring under the thrust generated by the continued rotation of the cam. The disc spring generates a reaction force after being compressed. When the butterfly valve is fully opened, the reaction force of the disc spring reaches its maximum. The damping torque generated by the reaction force eliminates all mechanical matching clearances from the driver power source to the lower part of the valve shaft, thereby eliminating tiny swings in the bud.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] During the opening process of the device, the cam rotates to drive the projection and the push rod to compress the disc spring to generate a reaction force, thereby generating a reverse torque on the lower shaft. The reverse torque is transmitted to the power source of the drive device through a series of mechanical connection structures (valve shaft, pin, key, worm gear, worm, etc.), thereby eliminating the swing of all transmission parts caused by the gap, effectively reducing the impact vibration of the water flow on the butterfly valve disc, and greatly improving the service life of the butterfly valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a front cross-sectional view of the present invention.

[0020] Figure 2 This is a diagram showing the position relationship between the cam, push rod and disc spring when the butterfly valve is in the fully open state.

[0021] Figure 3 This is a bottom view of the butterfly valve in the fully closed state.

[0022] Description of the markings in the figure:

[0023] 1. Base box, 2. Cam, 3. Push rod, 4. Disc spring, 5. Disc spring adjustment rod, 6. Valve shaft adjustment rod, 7. Cover plate, 8. First O-ring, 9. Second O-ring, 10. Third O-ring. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example

[0026] like Figure 1-3 As shown, the present invention provides a butterfly valve anti-water vibration mechanical damping device, which is installed at the bottom of the butterfly valve body and is transmission-connected to the lower end of the valve shaft. It consists of a base box 1, a cam 2, a push rod 3, a disc spring 4, a disc spring adjustment rod 5, a valve shaft adjustment rod 6 and a cover plate 7.

[0027] The base box 1 is installed at the bottom end of the valve body and is a hollow symmetrical structure. Its top surface is rigidly connected to the bottom surface of the butterfly valve body through multiple bolts, and a first O-ring 8 is provided at the contact surface to further reduce the risk of axial leakage.

[0028] The cam 2 is installed in the base box, and its shoulder end face is rigidly connected to the lower shaft end face of the butterfly valve by several bolts. A second O-ring 9 is arranged between the outer edge of the shoulder and the inner hole of the base box 1 to prevent leakage caused by water leakage of the lower shaft from penetrating into the base box 1.

[0029] The push rods 3 are square in shape, and two are provided in the base box 1, respectively mounted on the upper and lower sides of the cam 2. One end of each push rod 3 is pressed and contacted with a disc spring 4 to generate damping, and the other end is in contact with a disc spring adjustment rod 5.

[0030] According to the requirements of compression amount and damping torque, multiple disc springs 4 can be provided and divided into two groups, which are respectively located at the ends of the two push rods 3.

[0031] The disc spring adjustment rod 5 is located at the left and right ends of the base box, and is used to adjust the initial compression amount of the disc spring 4 and the synchronization of the compression of the two groups of disc springs.

[0032] The flange end of the valve shaft adjusting rod 6 is pressed by the cam 2 on the lower end surface of the valve shaft, but can rotate relatively. The middle part of the valve shaft adjusting rod 6 matches with the inner hole of the cam, and a third O-ring 10 is provided to prevent the possibility of water seepage and leakage of the valve shaft. The end thread matches with the center screw hole of the cover plate. The function of the adjusting rod is to adjust the axial concentricity of the valve disc.

[0033] The cover plate 7 is installed at the mouth end of the base box 1 and is rigidly connected by a plurality of bolts to fix the valve shaft adjustment rod 6 and prevent the push rod 3 from sliding out and preventing dust.

[0034] The operating principle of the device is as follows:

[0035] During the opening process of the butterfly valve, as the opening increases, the flow velocity continues to increase, and the turbulent disturbance also continues to increase. Generally, when it is opened to about 75°, the impact force of water on the left and right sides of the valve disc becomes closer and closer, which causes the frequency of the valve disc's slight axial rotation (caused by mechanical fit clearance) to increase. The frequency reaches the maximum when it is opened to 90° (fully open). At the same time, as the use time increases, due to fatigue deformation of the metal material, the slight vibration becomes a larger vibration, which eventually leads to the failure of the butterfly valve.

[0036] Once the butterfly valve opens to the set angle (generally set to 70° according to actual conditions), the cam 2 will also rotate to the set angle with the valve disc shaft. At this time, the protrusion on the cam 2 contacts the matching clamping part on the push rod 3 and generates a lateral thrust. The push rod 3 compresses the disc spring 4 under the thrust generated by the continued rotation of the cam 2. The disc spring 4 generates a reaction force after being compressed. When the butterfly valve opens to 90° (fully open), the reaction force of the disc spring 4 reaches its maximum. The damping torque generated by the reaction force eliminates all mechanical matching clearances from the driver power source to the lower part of the valve shaft (it can also be said that the contact surface is leaning to one side and a certain contact pressure ratio is generated), thereby eliminating tiny swings (rotations) in the bud.

Claims

1. A mechanical damping device for butterfly valve to resist water flow vibration, installed at the lower end surface of the butterfly valve body, characterized in that: The device comprises a base box (1) with an opening facing downward, a cover plate (7) fixed at the opening of the base box (1) by bolts, a cam (2) installed in a circular hole of the base box (1) rotatably along with the valve flap shaft, a push rod (3) that rotates in cooperation with the cam (2) to produce lateral movement, and a disc spring (4) that compresses and produces a reaction force in cooperation with the lateral movement of the push rod (3); The cam (2) is cylindrical, the top surface of the first-stage cylinder with a larger radius contacts the bottom surface of the valve disc shaft and rotates with the valve disc shaft, and two protrusions are provided on the outer surface of the second-stage cylinder with a smaller radius at intervals of 180 degrees; The push rod (3) has a square cross section and can be installed in a straight groove of the base box (1) in a linearly slidable manner. A clamping portion cooperating with the protrusion is provided at the middle concave portion of the push rod (3), and one end of the disc spring (4) is pressed and contacted with the inner end surface of the straight groove, and the other end is in contact with the inner end surface of the push rod (3). When the cam (2) rotates, the protrusion contacts the clamping portion and drives the push rod (3) to move inward laterally to compress the disc spring (4) to generate a reaction force; The number of the straight grooves and push rods (3) and the number of the protrusions are both two, and the number of the disc springs (4) corresponding to each push rod (3) is one or more.

2. A mechanical damping device for butterfly valve against water flow vibration according to claim 1, characterized in that: A second O-type sealing ring (9) is provided between the outer edge of the first-stage cylinder and the inner wall of the circular hole of the base box (1) to prevent leakage caused by water leakage of the lower shaft from penetrating into the base box (1).

3. A mechanical damping device for butterfly valve against water flow vibration according to claim 1, characterized in that: The device also includes a disc spring adjustment rod (5), the inner end of which contacts the outer end surface of the push rod (3), and the outer end extends out of the side of the base box (1) to adjust the compression amount of the disc spring through a nut.

4. A mechanical damping device for butterfly valve against water flow vibration according to claim 1, characterized in that: The device also includes a valve shaft adjusting rod (6), the head of which passes through the center holes of the cover plate (7) and the cam (2) in sequence and then contacts the bottom surface of the valve disc shaft, and the tail is provided with an adjusting nut for adjusting the axial concentricity of the valve disc.

5. A mechanical damping device for butterfly valve against water flow vibration according to claim 4, characterized in that: A third O-type sealing ring (10) is provided between the valve shaft adjusting rod (6) and the central hole of the cam (2) to prevent water from seeping out of the valve shaft.

6. A mechanical damping device for butterfly valve against water flow vibration according to claim 1, characterized in that: The top surface of the base box (1) is rigidly connected to the lower end surface of the butterfly valve body via a plurality of bolts, and a first O-type sealing ring (8) is provided on the contact surface to prevent axial leakage.

7. A mechanical damping device for butterfly valve against water flow vibration according to claim 1, characterized in that: The working principle of the device is as follows: When the butterfly valve is opened to a set angle, the cam (2) rotates to the set angle along with the valve disc shaft. At this time, the protrusion on the cam (2) contacts the matching clamping part on the push rod (3) and generates a lateral thrust. The push rod (3) compresses the disc spring (4) under the thrust generated by the continued rotation of the cam (2). The disc spring (4) generates a reaction force after being compressed. When the butterfly valve is fully opened, the reaction force of the disc spring (4) reaches a maximum. The damping torque generated by the reaction force eliminates all mechanical matching clearances from the driver power source to the lower part of the valve shaft.

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