Laboratory vacuum pumps include liquid ring pumps, slide valve pumps, rotary vane pumps, Roots pumps, etc. These pumps are currently the main pump types in the vacuum process of various industries in China's national economy. In recent years, with the sustained and rapid development of China's economy, the downstream application industry of laboratory vacuum pumps has maintained a rapid growth momentum. At the same time, with the continuous expansion of vacuum pump application fields and other factors, China's vacuum pump industry has achieved sustained and steady development.
Liquid ring pump
Although the liquid ring pump is a rough vacuum pump, it still has a large market in China's petroleum, chemical, electric power, textile, paper, and pharmaceutical fields. The working principle of the liquid ring pump is abroad. The sales of the liquid ring pump account for 14% of the total vacuum pump market, second only to the dry pump. Since most of the liquid ring pump is a casting, the processing requirements are not high, and it is a labor-intensive product. The domestic liquid ring pump has a competitive advantage in price. The key is to improve the design, reduce the volume, reduce the weight, improve the efficiency, and reduce the energy consumption.
Slide valve pump
Because the spool valve pump is more durable and reliable, all kinds of vacuum furnaces, coating machines, drying and impregnation equipments at home and abroad use the slide valve pump as the foreline pump. The working principle of the slide valve pump is that the sliding valve pump castings are heavy and the processing workload is heavy. Larger, so foreign vacuum plants are looking for partners in China. In order to enable the domestic spool valve to enter the international market, it is necessary to further reduce the vibration and noise of the pump, prevent fuel injection and oil leakage, and improve the reliability of the long-term operation of the spool pump.
Rotary vane pump
With the continuous expansion of vacuum technology in various application fields, the demand for direct-coupled rotary vane pumps is increasing. Due to the large number of such pumps, the processing and assembly work is very large, and the price is very low, so some foreign vacuum manufacturers set up professional factories in China. The domestic small and medium-sized direct-coupled rotary vane pump has been technically passed, and the price is far cheaper than that of foreign pumps. Therefore, domestic pumps still have competitive advantages. The key is to solve the problem of shaft seal oil leakage and performance quality of rotary vane material and vacuum pump oil. To ensure the stability and reliable operation of the direct-coupled pump at high speed and high temperature, and to further improve the ability of the domestic direct-coupled rotary vane pump to remove water vapor.
From the perspective of the production of Roots pumps abroad, several large foreign companies, such as Leybold, Balzers, Alcal, Edwards and ULVAC, their sales of Roots pumps accounted for less than 5% of the global sales of Roots pumps. The total of these 5 are only 20%, the output of Roots pump is not large, but the price of the working principle of the Roots pump Roots pump is much higher than that of the domestic pump. Almost all large and small high-vacuum and medium-vacuum systems at home and abroad are equipped with Roots pumps in order to shorten the pumping time and improve production efficiency. Therefore, the domestic Roots pump must try to enter the international market on the basis of occupying the domestic market. It is necessary to further reduce the vibration and noise of the domestic Roots pump, completely solve the problem of shaft seal oil leakage, improve the appearance quality of the pump, and improve the smoothness and cleanliness of the pump. In addition, it is necessary to consider that the power frequency of some countries and regions is 60Hz, and it is necessary to ensure the reliability of the long-term operation of the Roots pump under the condition of increasing the speed.
The laboratory vacuum pump is characterized by a large pumping speed over a wide range of pressures;
The rotor has good geometric symmetry, so the vibration is small and the operation is stable. There is a gap between the rotor and between the rotor and the casing, no lubrication, and the friction loss is small, which can greatly reduce the driving power, thereby achieving a higher rotational speed;
No oil seal and lubrication are required in the pump chamber to reduce the contamination of the vacuum system by oil vapor;
There is no compression in the pump chamber and there is no exhaust valve. The structure is simple and compact, and is insensitive to dust and water vapor in the pumped gas;
The compression is relatively low, and the effect on hydrogen gas is poor;
The surface of the laboratory vacuum pump rotor is a curved cylinder with a complicated shape, which is difficult to process and inspect.