Water ring vacuum pump is very popular and widely used in various industries. Today, for example, in the production of paper industry, how to choose the appropriate water ring vacuum pump, many customers said that the selection of water ring vacuum pump is very complex, in fact, we only need to adhere to the following principles, we can easily achieve the rational configuration of water ring vacuum pump. Make the correct selection. Let’s have a look at it.
Choose energy saving water ring vacuum pump.
At present, there are several series of water-ring vacuum pumps, such as 2BE, 2BV, VG, which are suitable for papermaking industry in domestic and foreign markets. Through the development of new products of water-ring vacuum pumps for rough and low vacuum industry in recent years, the efficiency of water-ring vacuum pumps has been greatly improved. Water ring vacuum pump, under the condition of the experimental station, the highest efficiency of pumping dry air can reach 67%. It will be more efficient for paper mill to suck wet air.
Choose low speed water ring vacuum pump.
The efficiency of water ring vacuum pump is directly related to the speed. The relationship between the pump gas volume and the speed is one-order, while the relationship between the shaft power and the speed is approximately quadratic when the speed is high. When the rotational speed is increased by 10%, the gas volume is also increased by 10%, while the shaft power is increased by about 20%. Therefore, when choosing the vacuum pump, the water ring vacuum pump with low rotational speed should be selected as far as possible. It is better to choose the corresponding speed at the end of the impeller blade when the linear speed is below 18 m/s. At this time, the efficiency of the pump is usually higher. Of course, relative to the higher speed of the pump will pay more purchase costs, relative to the cumulative energy consumption, in the context of increasing emphasis on energy saving, it is obviously worthwhile to choose low-speed energy-saving vacuum pump.
The combination of vacuum points is reasonable.
Vacuum points with similar vacuum degree and space position should be combined and sucked by a larger vacuum pump. The combination should be considered to be conducive to pipeline layout, and the combination should distinguish the functional areas. The pump with partitions can be used at the same time when the gas volume is similar. For example, between the suction tank of upper and lower wool cloth and between different vacuum suction rollers, the pump with partition can be selected.
The volume of vacuum pump should be converted.
Because the gas is compressible, the volume of the gas will expand when the high pressure gas is reduced to low pressure gas. If it is necessary to combine the high vacuum chamber and the low vacuum chamber of the vacuum roller, the vacuum degree and the gas volume of the high vacuum chamber are – 65 kPa and 80 m3/min respectively, and the vacuum degree and the gas volume of the low vacuum chamber are – 40 kPa and 50 m3/min respectively, then the gas volume of the low vacuum chamber should be first converted to the gas volume at – 65 kPa, and the converted gas volume is 84.4 m3/min ((101.3-40)/(101.3-65) x5. 0 = 84.4), then the air volume of the pump should be 164.4 m3/min, rather than 130 m3/min.
The loss of vacuum pump piping should be considered properly.
The gas pumped from each vacuum element will flow in the pipeline with a certain pipeline loss, which will cause the pressure drop and volume expansion of the gas. In the case of reasonable design of pipeline size, the loss of pipeline can be 2-3 kPa (small value for high vacuum and large value for low vacuum).
Medium temperature correction should be appropriate.
Because the air pumped by vacuum pump on paper machine is wet air with higher temperature, and the working fluid of water-ring vacuum pump has higher water temperature because of various restrictions, which is inconsistent with the working condition calibrated on the performance curve of water-ring vacuum pump, so the temperature and water temperature need to be corrected. When the temperature is relatively high and the water temperature is relatively low, the revised air volume will be relatively small, and the selected pump will be relatively small, otherwise the selected pump will be larger. The specific temperature should be revised according to the parameters of the paper machine and the specific conditions of the paper mill. Usually, it is feasible to take temperature 45 and water temperature 35 for correction. Such correction results are safe and reliable.
These are the six important points for attention in the selection of water ring vacuum pumps in paper industry. Many customers will compare imports with domestic ones. As we said in the second point, the selection of pumps with higher rotational speed will cost more and have higher efficiency. However, both domestic and imported pumps should be used in accordance with the use of vacuum pumps. The right way to run the vacuum pump is to make the pump life longer.