The growing market of dry pumps is mainly driven by the rapid development of semiconductor industry, chemical industry and film industry.
In Japan, dry vacuum pumps have been used instead of oil-sealed mechanical pumps in semiconductor industry. More than 45% of semiconductor industry in Europe and America have replaced oil-sealed mechanical pumps with dry vacuum pumps, which greatly improves the performance and quality of products.
In order to meet the requirements of different application fields and different working conditions, there are multistage Roots vacuum pumps, multistage claw vacuum pumps, screw vacuum pumps, scroll vacuum pumps, reciprocating piston vacuum pumps and turbine oil-free vacuum pumps abroad. The ultimate pressure ranges from 10 Pa to 10^-2 Pa, and the pumping speed ranges from 20 m3/h to 500 m3/h. Edward Dry Pump is the main choice for domestic enterprises, so the vacuum application solutions and Edward Vacuum Pump Maintenance Package service provided by Dongguan Suicheng Vacuum Equipment Co., Ltd., the corresponding Chinese mainland Edward high-quality service provider, for the majority of new and old customers also play a vital role.
Although the liquid ring pump belongs to the crude vacuum pump, it still has a large market in the fields of petroleum, chemical industry, electric power, textile, paper making and medicine in China.
In foreign countries, the sales of liquid-ring pumps account for 14% of the total vacuum pump market, which is second only to dry pumps. Because most of the liquid-ring pumps are castings and the processing requirements are not high, they are labor-intensive products, so the domestic liquid-ring pumps have competitive advantages in price. The key is to improve the design, reduce volume, reduce weight, improve efficiency and reduce energy consumption.
With the continuous expansion of vacuum technology in various application fields, the demand of direct-coupled rotary vane pump is increasing. Because of the large number of such pumps, the heavy workload of processing and assembling, and the low price, some foreign vacuum manufacturers have established specialized factories in China.
Domestic small and medium-sized direct-coupled rotary vane pumps have passed the technical barrier and their prices are much cheaper than those of foreign pumps. Therefore, domestic pumps still have competitive advantages. The key is to solve the problems of oil leakage from shaft seals, the performance and quality of rotary vane materials and vacuum pumps, to ensure the stable performance and reliable operation of direct-coupled rotary vane pumps at high speed and high temperature, and to further improve the steam extraction of domestic direct-coupled rotary vane pumps. Ability.
Judging from the production situation of Roots pumps abroad, several large foreign companies, such as Leybold, Balzers, Alcatell, Edwards and ULVAC, account for no more than 5% of the global sales of Roots pumps. The total output of these five pumps is only 20%. Roots pump output is not large, but the price of Roots pumps abroad is much higher than that of domestic pumps.
Almost all large or 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, domestic Roots pumps must try to enter the international market on the basis of occupying the domestic market. In this way, we must further reduce the vibration and noise of domestic Roots pumps, thoroughly solve the problem of oil leakage from shaft seals, and improve the appearance quality of pumps. High cleanliness and cleanliness in the pump.
In addition, the power supply frequency of some countries and regions is 60 Hz, and the reliability of long-term operation of Roots pump under the condition of increasing speed should be ensured. Domestic air-cooled direct-exhaust Roots pumps are progressing rapidly and technically mature. Because the pump is equipped with a gas cooler under the exhaust port, part of the cooled gas is returned to the pump chamber through the pipeline to cool the rotor, so that the heat of compression is balanced, so the pump can discharge the air directly.
In order to meet the requirements of different limit vacuum degree, this kind of pump can be used in series. Generally, an air-cooled direct-discharge air Roots pump is added in front of the pump, which achieves a limit vacuum of one order of magnitude higher than that of the previous pump. Because there is no working medium in the pump chamber, this kind of pump is actually a dry pump. The air-cooled direct-discharge Roots pump and its unit have been tested for a long time in petroleum, chemical, plastic, pesticide, steam turbine rotor dynamic balance, aerospace space space simulation and other devices, so it should be vigorously promoted and applied in China.
Molecular pumps are used to replace cryogenic pumps in many foreign semiconductors, especially in sputtering, etching and LCVD devices. Composite molecular pumps and traction pumps are used as main pumps.
Because the pumping speed of the molecular pump is only one fourth of that of the cryopump with the same caliber, the exhaust time of the molecular pump is longer than that of the cryopump. In order to improve the pumping speed, a low-temperature cold plate at the entrance side of the molecular pump, called a low-temperature molecular pump, is installed abroad. Water vapor is captured by the low-temperature plate, while other gases are pumped by the molecular pump.
The application of the cryogenic molecular pump in the vacuum coating device not only improves the production efficiency but also improves the film quality. With the rapid development of China’s semiconductor industry, film industry and scientific research, molecular pumps should be the focus of the development of China’s vacuum pump manufacturing industry. First of all, molecular pumps need to build a complete series from small to large to meet the needs of different occasions.
The water ring pump is a kind of coarse vacuum pump. The maximum vacuum it can obtain is 2000-4000Pa, and the air ejector in series can reach 270-670Pa. Water ring pump can also be used as a compressor, known as water ring compressor, is a low-pressure compressor, its pressure range is 1-2 x 10 ^ 5Pa gauge pressure.
Water ring pumps were initially used as self-suction pumps, and then gradually used in petroleum, chemical industry, machinery, mining, light industry, medicine and food and many other industrial sectors. In many industrial processes, such as vacuum filtration, vacuum water diversion, vacuum feeding, vacuum evaporation, vacuum concentration, vacuum moisture regain and vacuum degassing, water ring pumps are widely used. Due to the rapid development of vacuum application technology, the water ring pump has been attached great importance in obtaining rough vacuum. Because the gas compression in the water ring pump is isothermal, it can extract flammable and explosive gases, in addition, it can also extract dust and water containing gases. Therefore, the application of the water ring pump is increasing.
The pump body is equipped with appropriate amount of water as working fluid. When the impeller rotates clockwise, the upper inner surface of the water ring just touches the top of the blade (in fact, the blade has a certain insertion depth in the water ring). At this time, a crescent-shaped space is formed between the hub and the water ring of the impeller, which is divided into several small cavities equal to the number of blades by the impeller.
If the lower part of the impeller is 0 degree as the starting point, the volume of the small chamber increases from small to large when the impeller rotates 180 degrees, and is connected with the suction port on the end surface. At this time, the gas is absorbed, and at the end of the suction, the small chamber is isolated from the suction port; when the impeller continues to rotate, the small chamber becomes smaller and compresses the gas; when the small chamber is connected with the exhaust port, the gas is discharged out of the pump.
In summary, the water ring pump relies on the volume change of the pump chamber to achieve aspiration, compression and exhaust, so it belongs to the variable-volume vacuum pump.
Because the piston vacuum pump is durable and reliable, all kinds of vacuum furnaces, coating machines, drying and impregnation equipment at home and abroad use the sliding valve pump as the front pump, but the sliding valve pump castings are heavy and the processing workload is large, so foreign vacuum factories are looking for partners in China.
In order to make domestic spool pump enter the international market, it is necessary to further reduce the vibration and noise of the pump, eliminate oil injection and leakage, and improve the reliability of long-term operation of spool pump.