At present, the development of various vacuum pumps is more and more affected by vacuum applications. The general vacuum system can not meet the requirements of clean and oil-free corrosion resistance. Therefore, in recent years, the market demand of dry vacuum pumps is very large, and the vacuum products have been updated. A large number of oil-free vacuum systems have been replaced by oil-free and clean vacuum systems. Almost every large vacuum company abroad produces various types of dry vacuum pumps. Screw vacuum pump is a non-contact dry pump. It is an ideal pump in the early 1990s. It occupies the market with its advantages of wide pumping speed range, simple and compact structure, no friction of air extraction chamber components, long service life, low energy consumption and no oil pollution. However, most of its manufacturing technology is mastered by foreign countries. China is still in its infancy, and the market has great demand for dry pumps At present, the development of various vacuum pumps is more and more affected by vacuum applications. The general vacuum system can not meet the requirements of clean and oil-free corrosion resistance. Therefore, in recent years, the market demand of dry vacuum pumps is very large, and the vacuum products have been updated. A large number of oil-free vacuum systems have been replaced by oil-free and clean vacuum systems. Almost every large vacuum company abroad produces various types of dry vacuum pumps. Screw vacuum pump is a non-contact dry pump. It is an ideal pump in the early 1990s. It occupies the market with its advantages of wide pumping speed range, simple and compact structure, no friction of air extraction chamber components, long service life, low energy consumption and no oil pollution. However, most of its manufacturing technology is mastered by foreign countries. China is still in its infancy, and the market has great demand for dry pumps Present situation of dry vacuum pump Due to its superior performance, dry screw vacuum pump has become the preferred vacuum equipment in microelectronics, semiconductor, pharmaceutical, precision processing and other industries in Europe, America and Japan. On the basis of screw compressor, Japan has long developed the multi head rotor profile of vacuum pump and put it into the market. Several German vacuum equipment companies have also gradually developed equal pitch and variable pitch rotor profiles, and have done a lot of research on rotor and body cooling. Key technical problems of screw pump: Structure of dry screw pump: The structure of screw vacuum pump is mainly composed of screw rotor, shell, cooling circulation and sealing materials. The transmission shaft is connected with the driving rotor and drives the driven rotor to rotate through the synchronous gear. A cooling water channel is opened on the shell to cool the temperature of the rotor and exhaust port. The synchronous gear and bearing are lubricated with oil. The interior of the bearing and housing is sealed by seals to achieve the effect of oil-free. The structure of dry screw vacuum pump is similar to that of oil-free screw compressor in sealing and lubrication. Generally, mechanical seals are used at the exhaust end of vacuum pumps, and double lip seals are commonly used at the inlet side. In terms of transmission mode, at present, the common is direct connected motor, which is connected with rotor by coupling, and very few are driven by belt or chain. Due to no internal compression process, the exhaust temperature of equal pitch screw pump is very high (about 110 ℃). If the cooling effect is not good, it will cause deformation of rotor and casing and affect the sobbing effect. Therefore, cooling the casing is an essential link, and water cooling is a common method. Cooling water is supplied to the outer side of the bearing in the casing body to cool the casing and then the rotor. Laibao company applies water cooling inside the rotor to increase the service life of the rotor and achieve good cooling effect. However, this kind of structural design (two-stage type) requires certain technical and processing level support. Sometimes the cooling effect cannot be achieved by water cooling, so the cooling gas (mostly nitrogen) is usually passed near the rotor at the exhaust end. Now the mainstream screw vacuum pump abroad adopts this method. This method has several advantages: it can cool the casing of the rotor and reduce the exhaust temperature; Second, when the gas contains particles, it can prevent particle deposition or chemical reaction from causing explosion. Overview of dry vacuum pumps produced by domestic and foreign companies (1) KDP and SDV series screw vacuum pumps of Taher company. Taher acquired Kenny vacuum. Kenny is a professional manufacturer of vacuum equipment in the United States with a long history. It is also in a world position in the manufacturing of screw vacuum pump. KDP series is a vacuum pump with equal pitch rotor, and SDV is a variable pitch screw pump. Both are water-cooling systems, and air cooling systems can be selected. SDV is an improvement based on KDP. The variable pitch screw pump can realize the internal compression of gas, reduce the exhaust temperature, and save 30% energy compared with the same pitch. Niflon coating is adopted on the rotor, i.e. the layer is Ni and the second layer is PFA. Even if the PFA is worn, the Ni layer can achieve corrosion protection, and kalrez perfluorinated rubber sealing ring is adopted. SDV series is the screw vacuum pump mainly promoted by Kenny company. (2) The srewtine series screw oil-free compression vacuum pump officially launched by LeiBao company in Germany at the end of 2002 is a dry pump specially designed for industrial applications (non semiconductor applications). It is a new design and is specially used to solve the difficult vacuum problems in industrial applications. Such as dust, tar, etc. The pump also adopts variable pitch rotor with internal compression process. There is no internal valve in the pump cavity, so it has strong resistance to dust and tar. The screw of the pump adopts internal hollow cooling, which can reduce the rotor temperature and thermal deformation, so the service life of the screw is prolonged. (3) Cobran series screw pump of Germany puxu company is a vacuum pump for manufacturing process, which is especially suitable for various process flows in chemical and pharmaceutical industries. Puxu is one of the suppliers of vacuum pumps, blowers and compressors in the world. The quality of vacuum pumps is high. Compared with other manufacturers, puxu has a high market share in Europe and the price is expensive. (4) VSA / VSB series of Richler, Germany. VSA is an equal pitch rotor with good market evaluation and stable performance. VSB Series event pitch rotor design (non-linear tooth shape design), like other companies, changes the power consumption and exhaust temperature of the pump through internal compression. Without two-stage compression and intermediate cooling, a single stage can achieve very high vacuum. The sealing element is improved. The static sealing element is preferably PTFE or the sealing element added with PTFE. The dynamic sealing element uses double sealing lips on the suction side of the vacuum pump, and a simple sealing ring with gas overflow prevention is used on the exhaust side of the vacuum pump to prevent solid substances from entering the pump. (5) Japanese manufacturers. Screw vacuum pumps are widely used in Japan, and are widely used in semiconductor and LCD industries. Yoshimura soldiers of Dahuang Co., Ltd. applied for patents on single head first-class screw rotors for a long time and made in-depth research on rotors. Hitachi also made research on screw pump in the early stage. 3. Research prospect: The domestic research of dry screw vacuum pump is still in the initial stage, and many technical problems have not been solved. For example, the rotor coating anti-corrosion technology, reducing the temperature of the exhaust port and increasing the utilization rate of the rotor area are still very difficult. When extracting some active gas, due to the high exhaust temperature, it also needs to be considered in the design. When used in the occasion where the volume needs to be controlled, how to reduce noise should also become the research direction, However, its superior performance determines that it will dominate the vacuum equipment industry, just like the dominant position of screw compressor in the industry. Dry Screw Vacuum Pumps Used In Fruit Freeze Drying Industry

What is the ambient temperature of the vacuum pump? Too high or too low temperature will affect the operation of the equipment and affect many operations of the equipment. Therefore, users should learn to adjust the temperature and always keep the equipment above a good temperature. So what is the appropriate ambient temperature to use it? 1. Gas analysis and partial pressure measurement under vacuum conditions are usually completed by dynamic mass spectrometer. If the medium to be transported contains solid particles, a filter screen shall be added at the pump inlet; If ferromagnetic particles are contained, a magnetic filter shall be added. 2. The ambient temperature of the vacuum pump in use shall be lower than 40, and the temperature rise of the motor shall not exceed 75. After 1000 hours of normal operation of the magnetic pump, remove the bearing and end face moving ring, check the wear, and replace the vulnerable parts that cannot be reused. For the medium easy to precipitate and crystallize, clean the conveying liquid immediately after use and discharge the liquid accumulated in the pump. The vacuum pump must always be clean. No other articles shall be placed on the vacuum pump, and the channels around the pump shall not be blocked. Always pay attention to the tightness of the V-belt and adjust it. Always pay attention to whether each pipe joint leaks and whether the pre vacuum in the box is reduced, otherwise it needs to be repaired in time; Always pay attention to whether the cooling water is unblocked. Start intermittently 4-6 times within 2S each time to overcome the large torque during startup. Here, we need to know the ambient temperature of the vacuum pump, and we must measure whether the ambient temperature meets the corresponding normal range before formal use. In addition to keeping the vacuum pump at a good temperature, we must also do a good job in heat dissipation. Liquid Ring Vacuum Pump Used in Block Moulding Machine in EPS Production

Vacuum pump is the main force of many science and technology, and provides necessary conditions for the operation of many laboratory application equipment. Unfortunately, if the pump is exposed to acid or organic chemical fumes for a long time, it will cause some practical maintenance problems. Especially for the oil sealed rotary vane pump, exposing the oil to chemical steam will lead to oil deterioration or decomposition, which will affect the function of the oil mist separator of the vacuum pump. Many applications require a high degree of vacuum, so vane pumps are required. These high vacuum pumps are essential for installing the vacuum pump oil mist separator. 1: Read the instruction manual carefully After purchasing the pump, carefully read the manual, check the operation precautions, select the appropriate vacuum pump oil according to the suggestions in the manual, and select the vacuum pump oil fume filter according to the pump model. The manual usually recommends the time of oil change. 2: Warm up the pump Run the pump for 20-30 minutes before connecting it to the vacuum system. Consider installing manual valves to facilitate the preheating process. 3: Do not block the pump outlet The pump outlet is blocked, which will cause the pump to stop working. In the worst case, overpressure in the pump may loosen the seal around the oil mirror glass, resulting in leakage and maintenance. Install the vacuum pump oil mist separator to make the air flow more stable. 4: The inlet cold trap is used to protect the pump from corrosive steam The cold trap at the inlet can not only protect the pump from corrosive steam, but also reduce the steam load on the pump, so it can work more effectively. Ensure that the temperature of the solvent is low enough, such as using liquid nitrogen (for highly volatile solvents). 5: When handling condensable vapors, use gas ballasts The air ballast of the vacuum pump uses air to push the condensate to the outlet through the pump. For applications with high steam load and corrosive gas, the mixing pump (diaphragm pump / rotating blade combination) will maintain the vacuum state of the oil storage tank and continuously distill steam and corrosive gas from the pump oil, so as to reduce corrosion and greatly prolong the service life of the pump. The oil change cycle also extends the replacement cycle of the vacuum pump oil mist separator. 6: Use an air inlet filter to protect the pump from particulate contamination Use the air inlet filter to remove abrasive particles from the pump oil and rotating equipment. Reduce the pump oil pollution caused by impurities, and cooperate with the oil fume filter of the vacuum pump to effectively improve the performance of the vacuum pump. 7: Run the pump after use to remove the solvent from the oil After completing the operation, you need to open the air ballast, close the air inlet and let the pump run for a few minutes. By operating the pump near the maximum vacuum but with good air circulation, many solvents dissolved in the oil can be removed, thereby reducing internal corrosion during shutdown. Vacuum Pump Heat Treatment Guide,Heat Treatment Equipment Liquid Ring Vacuum Pump