Selection of vacuum pumps

Thread Content

　　With the development of modern technology, vacuum pumps, as universal devices in this economic society, are being used more and more widely in actual industrial production, and the requirements for them are also becoming more specialized. Choosing the right vacuum pump is therefore a very important aspect of our daily production processes. This article covers the basic principles for selecting vacuum pumps: When choosing a vacuum pump, one should first consider the main requirements regarding vacuum level as well as the key performance characteristics that are of importance. Only after the pump meets these requirements should other factors related to selection be taken into account. When selecting a vacuum pump, the following points should be taken into consideration: 1. The operating pressure of the vacuum pump must meet the requirements regarding the ultimate vacuum level and operating pressure of the vacuum equipment. For example, vacuum coating requires a vacuum level of 1×10-5 mBar; therefore, the ultimate vacuum capacity of the vacuum pump selected should be ≤5×10-6 mBar. Typically, the vacuum level of the pump should be half to an order of magnitude higher than that of the vacuum equipment. 　　2. Select the appropriate operating vacuum level for the vacuum pump. Each pump has a certain operating pressure range; for example, the ultimate vacuum level of the SVF-E1-20 is 0.1 mBar, while its stable operating pressure range is from 1.0 mBar to 0.5 mBar. Therefore, the pump’s operating point should be selected within this range. 　　3. At its operating pressure, the vacuum pump should be able to remove all the gas generated during the processing of the vacuum equipment within a specified time frame; this requires taking into account, to a certain extent, the pumping speed of the vacuum pump when it is under load. 　　4. Select the vacuum pump selectively based on the type of medium being processed. If a single pump cannot meet the pumping requirements, it is also possible to consider using a combination of multiple pumps. Since the pumping speed curves for pumping oil-free air and helium are different in SVF-E1-20, the properties of the medium to be pumped must be fully considered when selecting a vacuum pump. 　　5. Understand the composition of the gas being sampled, whether it contains condensable vapors, particulate dust, as well as whether it is corrosive or toxic. When selecting a vacuum pump, it is necessary to know the composition of the gas to be evacuated, and choose a pump suitable for that gas. If there are corrosive gases, the material used for the pump’s chamber should be corrosion-resistant; in the case of toxic gases, the vacuum pump must also take into account its leakage rate to prevent toxic gases from escaping and causing industrial accidents. It contains condensable vapors, particles, and corrosive gases; therefore, it is advisable to install auxiliary equipment such as condensers and dust collectors on the pump’s inlet pipeline. 　　6. Requirements of vacuum equipment regarding oil contamination. If the equipment requires absolutely no oil, then various oil-free pumps should be used, such as water ring pumps, oil-free vortex pumps, and dry screw pumps. If the equipment also has strict requirements regarding water vapor, dust, etc., then oil-free dry pumps should be chosen, such as vortex dry pumps, screw dry pumps, and molecular pumps. When the requirements are not strict, a pump with oil can be used, along with various measures to prevent oil contamination such as cold traps, baffles, and oil traps, which can also meet the requirements for a clean vacuum environment. 　　7. The impact of vacuum pumps on the environment. In environments where oil contamination is not allowed, oil-free vacuum pumps can be used; in environments where dust contamination is not permitted, pumps that do not generate debris, such as floating vortex pumps or oil-free diaphragm pumps, can be chosen; in environments where noise pollution is not acceptable, silent pumps can be utilized. 　　8. Does the vibration generated by the vacuum pump during operation have an impact on the manufacturing process and the surrounding environment? If the process does not permit it, a vibration-free pump should be selected or vibration prevention measures should be taken. 　　9. Cost factors. The cost of a vacuum pump should take into account both the one-time purchase cost and the overall operating costs. One-time costs include the cost of the vacuum pump itself as well as the costs associated with the surrounding piping systems; comprehensive usage costs encompass daily operation and maintenance expenses, repair costs, and the costs related to the pump’s lifespan. 　　10. Other special requirements. These mainly include AC/DC power supplies, power consumption, weight, volume, electrical control, heat dissipation, gas pipeline connections, as well as industry-specific requirements.