Centrifugal pump shutdown sealing device based on axial thrust

Abstract

A centrifugal pump shutdown sealing device based on axial thrust comprises a pump cover (1) and an annular plate (11), an inner cylinder (3) and an outer cylinder (5) are connected between the pump cover and the annular plate in a sealed mode, an inner corrugated pipe (4) and an outer corrugated pipe (8) are welded between the sections of the inner cylinder and between the sections of the outer cylinder respectively, a water injection port (6) is formed in the outer cylinder, and a guide rod (7) penetrates through the annular plate and is fixedly connected to the pump cover. The right end of the guide rod is sleeved with a spring (10) and screwed with an adjusting nut (11), the left side of the annular plate is connected with a rubber annular plate (13), a shaft sleeve (14) is fixed to the pump shaft, and the rubber annular plate can be attached to the right end face of the shaft sleeve. The sealing device has the advantages that all the components are installed on the pump cover, the load of the pump shaft is reduced, unbalanced force cannot be generated on the pump shaft, the sealing device is not prone to being damaged when the machine stops, and no adverse effect is generated on the pump shaft. When the centrifugal pump works, the rubber ring plate on the ring plate is separated from the shaft sleeve, and when the centrifugal pump stops, the rubber ring plate is tightly attached to the shaft sleeve.

Description

Technical Field

[0001] The utility model relates to a shutdown sealing device for a centrifugal pump. Background Art

[0002] Centrifugal pumps with dynamic seals must be equipped with shutdown sealing devices to prevent the fluid in the pump body from leaking along the pump shaft when shut down.

[0003] The structure of the existing shutdown sealing device includes a static ring and a dynamic ring. The static ring is connected to the outside of the pump cover, and the dynamic ring is sealingly sleeved on the pump shaft. The dynamic ring can move away from the static ring or move towards the static ring. The movement of the dynamic ring away from the static ring is driven by the flyweight, which is movably connected to the pump shaft. When the pump shaft rotates, the flyweight generates centrifugal force; the movement of the dynamic ring towards the static ring is driven by a spring, which is sleeved on the pump shaft. When the pump shaft stops, the centrifugal force of the flyweight disappears, and the spring pushes the ring to fit tightly against the static ring to achieve shutdown sealing.

[0004] The above-mentioned moving ring, fly iron and other components are all installed on the pump shaft and rotate with the pump shaft, which increases the load on the pump shaft. Among them, the fly iron is movably installed on the pump shaft. When the pump shaft rotates, unbalanced force will be generated, the moving parts will vibrate, and the parts are prone to fatigue; at the same time, the unbalanced force will also damage the pump shaft. Utility Model Content

[0005] In response to the above problem, the utility model proposes a centrifugal pump shutdown sealing device based on axial thrust. The shutdown sealing device has no components similar to flying irons, no unbalanced force is generated, the shutdown sealing device is not easily damaged, and has no adverse effect on the pump shaft; when the centrifugal pump is shut down, the seal between the pump shaft and the pump cover can be reliably achieved; when the centrifugal pump is working, the sealing component is not worn.

[0006] The technical solution of the present utility model is a centrifugal pump shutdown sealing device based on axial thrust, which includes a pump cover 1, a pump shaft 2 passing through the pump cover and entering the pump body, and is characterized in that an inner cylinder 3 and an outer cylinder 5 are sealed and connected on the right end surface of the pump cover, an annular cover plate 9 is sealed and welded between the right ends of the inner cylinder 3 and the outer cylinder 5, the inner cylinder 3 is disconnected, and an inner bellows 4 is sealed and welded between its sections, the outer cylinder 5 is disconnected, and an outer bellows 8 is sealed and welded between its sections, a water injection port 6 is provided on the outer cylinder, the water injection port is communicated with the water outlet of the centrifugal pump through a water pipe, the right end surface of the cover plate is connected to the ring plate 12, a plurality of guide rods 7 pass through the ring plate, the guide rods are symmetrically fixedly connected to the pump cover, an adjusting nut 11 is screwed on the right end of the guide rod, a spring 10 is sleeved on the guide rod, and the spring is located between the adjusting nut and the ring plate; a rubber ring plate 13 is connected to the left side of the ring plate, a shaft sleeve 14 is sealed and fixed on the pump shaft, and the rubber ring plate can be attached to the right end surface of the shaft sleeve.

[0007] The beneficial effects of the present invention are as follows: when the centrifugal pump is working, the high-pressure water of the centrifugal pump enters between the outer cylinder and the inner cylinder through the water injection port, generates an axial thrust on the cover plate, causes the ring plate to move to the right, and the rubber ring plate on the ring plate is out of contact with the shaft sleeve. When the centrifugal pump is working, the rubber ring plate is not worn; when the centrifugal pump is shut down, the pressure in the centrifugal pump drops greatly, and the axial thrust drops accordingly. The elastic force of the spring causes the ring plate to move to the left, and the rubber ring plate is tightly attached to the shaft sleeve to achieve shutdown sealing; the components of the shutdown sealing device are all installed on the pump cover, which reduces the load on the pump shaft. There are no movable parts similar to fly iron on the pump shaft, and no unbalanced force will be generated on the pump shaft. The shutdown sealing device is not easy to be damaged and has no adverse effect on the pump shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a structural diagram of the present utility model.

[0009] Figure symbols: 1-pump cover, 2-pump shaft, 3-inner seat, 4-inner bellows, 5-outer cylinder, 6-water inlet, 7-guide rod, 8-outer bellows, 9-cover plate, 10-spring, 11-adjusting nut, 12-ring plate, 13-rubber ring plate, 14-sleeve, 15-sealing ring, 16-pressure ring plate, 17-flushing outlet, 18-blocking. DETAILED DESCRIPTION

[0010] A centrifugal pump shutdown sealing device based on axial thrust, which includes a pump cover 1, a pump shaft 2 passing through the pump cover and entering the pump body (the left side of the pump cover is the pump body, and the pump body is not drawn in the accompanying drawings), which is characterized in that an inner cylinder 3 and an outer cylinder 5 are sealed and connected on the right end face of the pump cover, an annular cover plate 9 is seal-welded between the right ends of the inner cylinder 3 and the outer cylinder 5, the inner cylinder 3 is a disconnected structure, and an inner bellows 4 is seal-welded between its sections, the outer cylinder 5 is a disconnected structure, and an outer bellows 8 is seal-welded between its sections, and a water inlet 6 is provided on the outer cylinder, which is connected to the outlet of the centrifugal pump through a water pipe. The water inlet is connected, and the right end face of the cover plate 9 is connected to the ring plate 12 through a stud. Multiple guide rods 7 pass through the ring plate. The guide rods are symmetrically fixed to the pump cover. An adjusting nut 11 is screwed on the right end of the guide rod. A spring 10 is sleeved on the guide rod, and the spring is located between the adjusting nut and the ring plate; a rubber ring plate 13 is provided on the left side of the ring plate. The inner circle of the rubber ring plate is slightly larger than the pump shaft. The rubber ring plate is fixed to the ring plate by a clamping ring plate 16 and bolts. A shaft sleeve 14 is sealed and fixed on the pump shaft. A sealing ring 15 is provided between the shaft sleeve and the pump shaft. The rubber ring plate can be in contact with the right end face of the shaft sleeve.

[0011] The principle is that the outer cylinder and the inner cylinder form a closed cavity. When the centrifugal pump is working, the high-pressure water of the centrifugal pump passes through the water inlet and enters between the outer cylinder and the inner cylinder, generating axial thrust on the cover plate. The bellows is elastic, the ring plate can move to the right, and the rubber ring plate on the ring plate is out of contact with the shaft sleeve. When the centrifugal pump is working, the rubber ring plate is not worn; when the centrifugal pump is shut down, the pressure in the centrifugal pump drops greatly, and the axial thrust drops accordingly. The elastic force of the spring causes the ring plate to move to the left, and the rubber ring plate is tightly attached to the shaft sleeve to achieve shutdown sealing.

[0012] The left ends of the inner and outer cylinders can be welded to the pump cover. To facilitate production and installation, an annular cover plate is sealed and welded between the left ends of the inner and outer cylinders. An ear plate 19 is welded on the outer circle of the outer cylinder. A threaded seat 20 is provided on the pump cover, and the screws pass through the ear plate and are screwed onto the threaded seat.

[0013] In order to prevent particles in the fluid from accumulating in the cavity of the bellows, a flushing outlet 17 is provided on the outer cylinder to flush the inner cavity of the bellows. The flushing outlet is screwed with a plug 18. When the centrifugal pump is working, the flushing outlet is closed with a plug. When flushing is required, the plug is removed and clean water is connected to the water inlet.

[0014] The corrugated nodes of the inner bellows and the outer bellows can be multiple nodes. Considering that the axial displacement of the ring plate is not large, the corrugated nodes of the inner bellows and the outer bellows are both single nodes. The crest of the inner bellows faces the outer tube, and the crest of the outer bellows faces the inner tube. In this way, there is no dead angle on the inner bellows and the outer bellows, which is convenient for flushing the inner cavity of the bellows.

[0015] In order to reduce the radial distance between the outer tube and the inner tube, the wave crests of the outer bellows and the wave crests of the inner bellows are staggered along the axial direction, and the radial distance is reduced, which is beneficial to reducing the axial thrust on the cover plate and the pressure on the outer bellows.

Claims

1. A centrifugal pump shutdown sealing device based on axial thrust, comprising a pump cover (1), a pump shaft (2) passing through the pump cover and entering the pump body, wherein: An inner cylinder (3) and an outer cylinder (5) are sealed and connected on the right end surface of the pump cover. An annular cover plate (9) is sealed and welded between the right ends of the inner cylinder (3) and the outer cylinder (5). The inner cylinder (3) is disconnected, and an inner bellows (4) is sealed and welded between its sections. The outer cylinder (5) is disconnected, and an outer bellows (8) is sealed and welded between its sections. A water injection port (6) is provided on the outer cylinder, and the water injection port is communicated with the water outlet of the centrifugal pump through a water pipe. The right end surface of the cover plate is connected to the ring plate (12). A plurality of guide rods (7) pass through the ring plate. The guide rods are symmetrically fixed to the pump cover. An adjusting nut (11) is screwed on the right end of the guide rod. A spring (10) is sleeved on the guide rod. The spring is located between the adjusting nut and the ring plate. A rubber ring plate (13) is connected to the left side of the ring plate. A shaft sleeve (14) is sealed and fixed on the pump shaft. The rubber ring plate can be attached to the right end surface of the shaft sleeve.

2. The centrifugal pump shutdown sealing device based on axial thrust according to claim 1 is characterized in that: An annular cover plate is sealed and welded between the left ends of the inner cylinder and the outer cylinder, an ear plate (19) is welded on the outer circle of the outer cylinder, and a threaded seat (20) is provided on the pump cover, and a screw passes through the ear plate and is screwed on the threaded seat.

3. The centrifugal pump shutdown sealing device based on axial thrust according to claim 1, characterized in that: A flushing outlet (17) is provided on the outer cylinder, and a plug (18) is provided on the flushing outlet.

4. The centrifugal pump shutdown sealing device based on axial thrust according to claim 3 is characterized in that: The wave nodes of the inner bellows and the outer bellows are both single nodes, the wave crest of the inner bellows faces the outer tube, and the wave crest of the outer bellows faces the inner tube.

5. The centrifugal pump shutdown sealing device based on axial thrust according to claim 4 is characterized in that: The wave crests of the outer bellows and the wave crests of the inner bellows are staggered along the axial direction.

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