In recent years, with the development of production technology in China, the application of vacuum pump in production is more and more extensive. It is widely used in metallurgy, chemical industry, food, electronic coating and other industries. Vacuum pump includes water ring vacuum pump, dry vacuum pump, slide valve pump, rotary vane vacuum pump, roots vacuum pump and diffusion pump. Because of its increasingly prominent role in production, how to test the performance of water ring vacuum pump when purchasing a vacuum pump has become a major concern for many users. Today, we will take the water ring vacuum pump as an example to share several methods about the performance test of the water ring vacuum pump.
The water ring vacuum pump is eccentric installed in the pump shell with a multi blade rotor. When it rotates, the liquid is thrown to the pump shell to form a liquid ring concentric with the pump shell, and the liquid ring and the rotor blade form a rotary variable volume vacuum pump with periodic volume change. When the working liquid is water, it is called water ring vacuum pump.
The structure of the water ring vacuum pump is characterized by the installation of a star impeller on the pump shaft which is eccentric to the cylindrical pump shell. Before starting, water of a specified height is injected into the pump. When the impeller rotates, water is thrown to the four walls of the pump body due to the centrifugal force, forming a water ring concentric with the rotating shaft. The inner surface of the upper part of the water ring is tangent to the wheel shell, and the inner surface of the lower part of the water ring forms an air chamber with the wheel shell. The volume of the air chamber increases in the right half. In the first half of the ring, the vacuum is formed with the increase of the volume between the wheel shell and the water ring, so the air is open The crescent shaped air inlet on the end cover of the over pumping pipe and the vacuum pump shell is sucked into the vacuum pump; in the second half circle, the air is compressed with the reduction of the volume between the wheel shell and the water ring, and is discharged through another crescent shaped air outlet on the end cover of the pump shell. The impeller rotates continuously, and the water ring vacuum pump can pump out the air.
water ring vacuum pump operation test:
The water ring vacuum pump shall be operated and tested within the normal working range of the vacuum pump at the specified speed. The duration of the test shall not be less than 30min. During the operation test, the temperature of the bearing and the bearing of the vacuum pump, the tightness, noise and vibration of the shaft seal and the connecting part shall be checked. The internal friction of vacuum pump can be disassembled and inspected after vacuum pump test.
water ring vacuum pump performance test:
1. The performance test of water ring vacuum pump is to determine the air volume, speed, input power, efficiency and limit pressure (limit vacuum degree) of vacuum pump at a given speed and different suction pressure (vacuum degree). When measuring the performance of water ring vacuum pump, the gas temperature, atmospheric pressure and relative humidity at that time, as well as the temperature, pressure and water supply (flow) of working liquid (water) shall also be measured.
2. The number of measurement points for performance test shall not be less than 12, which must include: standard atmospheric pressure or close to standard atmospheric pressure point, specified (working) vacuum point and limit vacuum degree (air volume equal to zero or close to zero). In the area where the air volume curve of vacuum pump changes significantly, the density of measuring points can be selected appropriately.
3. When the water ring vacuum pump equipped with air ejector is tested, its measuring points shall be increased appropriately. In addition to measuring the performance data when the water ring vacuum pump is working alone, the vacuum degree, gas volume and ultimate vacuum degree when the water ring vacuum pump is working with the ejector shall also be measured.