RU2432499C1 - Pressurised low-noise pump - Google Patents

Abstract

FIELD: engines and pumps. ^ SUBSTANCE: pump consists of rotor, at console of which there attached is an impeller 10, screw 8, pump diffuser 11, casing 1 with integrated electric engine stator 2. Rotary part 5 of electric engine is attached at the shaft 3 between plain bearings 4. Input and output ducts 6, 14 are located along pump axis. Pump shaft 3 is hollow and acts as supply duct to impeller 10. Impeller 10 has a collar 15 that creates throttling gap 16 of hydraulic balancing device together with pump diffuser 11. Bearing plates 17, 18 are arranged at both sides of impeller 10. Rotor side play considerably exceed working gap 16 in bearing plate. ^ EFFECT: reduction of noise and vibration level, improvement of pump navigation characteristics. ^ 2 cl, 2 dwg

Description

The invention relates to the field of pump engineering and can be used for pumping various liquids, for example, in heating systems for cars, ships, and other closed systems, when high anti-cavitation qualities, tightness, and minimal noise and vibration levels are required.

A pump is known according to the author's certificate of the USSR No. 523195, IPC F04D 7/04, 07/30/1976, in which, to improve the cavitation characteristics of the pumps, an axial wheel - auger is installed in front of the working centrifugal wheel.

Closest to the invention is a sealed low-noise pump, consisting of a rotor, on the console of which an impeller is fixed, a screw, a guide apparatus, a pump housing with an integrated motor stator, the rotor part of which is fixed to the shaft between the plain bearings, and also with nozzles located along the pump axis suction and discharge (see US patent No. 4065232, CL 417/368, 12/27/1977. The pump has a built-in sealed electric motor and technological channels in the shaft, through which the fluid flows to the control to The drawbacks of this technical solution are the complexity of the design and the need to cool the motor with an external fan.

This technical solution, which is the closest to the proposed invention in terms of the task and technical result, has several disadvantages: the complexity of the design of the persistent heels, axial inlet and radial bend, which does not provide flow symmetry and is an additional source of unsteady forces and, therefore, vibration.

The objective of the present invention is to reduce noise and vibration, improving the cavitation qualities of the pump.

The problem is solved in that in a sealed low-noise pump, consisting of a rotor, on the console of which the impeller is fixed, a screw, a guide apparatus, a pump housing with an integrated motor stator, the rotor part of which is fixed to the shaft between the sliding bearings, as well as those located along the axis pump suction and discharge nozzles, according to the invention, the pump shaft is hollow and is a supply pipe to the impeller, the impeller has a collar that forms with the guide apparatus m throttle gap hydraulic balancing device, and on both sides of the impeller located heel, wherein the rotor axis run substantially exceeds the working air gap in the hydraulic balancing device.

The screw may be located inside the hollow shaft at the inlet.

This design provides complete axisymmetric flows and eliminates the appearance of unsteady forces that cause vibration of the pump.

The invention is illustrated by drawings, where:

figure 1 shows a longitudinal section of a pump;

figure 2 - node a in figure 1, showing the working gap in the hydrodynamic heel.

The pump consists of a housing 1, in which the stator 2 of the electric motor, the hollow shaft 3, rotating in the bearings 4 are placed. Between the bearings 4 on the shaft 3 is fixed the rotor part 5 of the electric motor. Bearings 4 are placed: lower - in the lower cover, which consists of two parts and in which the inlet pipe 6 is located; top - in the pump housing 1. In the upper cover 7, a discharge pipe 14 is made. In the lower part of the shaft 3, a screw 8 with a sleeve 9 is fixed inside. In the upper part of the shaft 3, the impeller 10 is attached. The fluid from the impeller 10 enters the guide apparatus 11 and enters the discharge pipe 14 through the annular outlet 12 with straightening vanes 13.

A shoulder 15 is made on the impeller 10, which forms a throttling gap 16 in the hydrosail with the guide apparatus 11 (figure 2). The impeller 10 rests before starting on the starting heel 17. The axial run of the rotor between the heels 17 and 18 are the gaps 20 and 19, and it significantly exceeds the working gap 16 in the hydrograph. The heel 18 protects against touching the impeller 10 and the guiding apparatus 11 in a hydrograph.

The pump operates as follows. The fluid from the suction pipe 6 enters the auger 8 and then into the impeller 10. When starting, the pump rotor rotates at the starting heel 17, the gap 16 is maximum and is approximately 0.95% of the axial run of the rotor. Due to the difference in the area of the seal on the front and rear wheels of the wheel 10, where the bearing 4 acts as a seal, an axial force arises upward. The pump rotor begins to move upward, while the gap 16 is set so large that the rotor is in equilibrium. The size of the working gap 16 in the hydrosail is 0.05-0.1 mm. If the force is not enough to lift the rotor, the resulting hydrostatic force reduces the specific pressure on the starting heel 17 and thereby reduces its wear during operation of the pump. The pressure of the screw 8 is calculated in such a way that it is sufficient to ensure cavitation-free operation of the impeller 10 in all feeding modes. The number of blades due to the increase in the input diameter in the impeller 10 is performed with a significantly larger number than the existing centrifugal wheels, which leads to an increase in the blade frequency f _l = z _l n / 60, where z _l is the number of blades of the wheel, n is the number of revolutions in minute of the pump rotor, shifting it to the high frequency range (f> 1000 Hz) and reducing the level of disturbances. The liquid from the heel plate enters the lubrication of the upper bearing 4, passes in the gap between the stator 2 and the rotor part 5 of the electric motor, cools them and enters the lower bearing 4, after which it is mixed with the liquid entering the suction.

The technical result of the invention consists in ensuring axisymmetric flows in the pump, reducing disturbances at the blade frequency, simplifying the hydraulic path and combining it with the cooling path of the electric motor and lubricating the bearings with the pumped liquid, which reduces vibration levels. Installing the auger at a distance from the impeller allows you to align the flow rates at the entrance to the impeller, which also helps to eliminate disturbances and reduce vibration levels. The vibration is also reduced by placing the screw in the sleeve (inside the shaft) without a gap.

An additional advantage of the proposed design is ease of assembly of the pump, maintainability.

The pump can also be used and built into pipelines without supporting the foundation, which can also ultimately lead to a reduction in the vibrations emitted by the pump.

Claims (2)

1. A sealed low-noise pump, consisting of a rotor, on the console of which the impeller is fixed, a screw, a guide apparatus, a pump housing with an integrated motor stator, the rotor part of which is fixed to the shaft between the plain bearings, and also with suction and discharge nozzles located along the axis of the pump , characterized in that the pump shaft is made hollow and is a supply pipe to the impeller, the impeller has a shoulder, which forms a throttle clearance of the hydraulic foot with a guide apparatus, and heels are located on both sides of the impeller, while the axial take-off of the rotor significantly exceeds the working clearance in the heel. 2. The sealed low noise pump according to claim 1, characterized in that the screw is located inside the hollow shaft at the inlet.

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