What do you need to know before purchasing large vacuum pumps
Large vacuum pumps have been designed with full consideration that they must be able to extract a variety of gases. It has been widely used in papermaking, coal mine, power plant, vacuum filtration, chemical industry, petrochemical, food processing and other industries. It can be used with a variety of driving devices, such as belt drive, reducer, synchronous motor, frequency converter, etc. In addition, in order to save space, a series operation mode driven by one motor can be adopted, and Zui can run four pumps in series at the same time.
1. The working pressure of large vacuum pumps should meet the requirements of the vacuum equipment's limit vacuum and working pressure. For example, a vacuum drying process requires a working vacuum of 10 mmHg, the ultimate vacuum of the selected large vacuum pump should be at least 2 mmHg, and Zui can reach 1 mmHg. Usually the limit vacuum degree of the pump is higher than that of the vacuum equipment, which is half to one order of magnitude.
2. Select the working point of large vacuum pump accurately. Each pump has a certain range of working pressure, such as: 2BV series water ring large vacuum pump working pressure range 760 mmHg ~ 25 mmHg (absolute pressure), in such a wide range of pressure, the pump pumping speed varies with pressure (specific changes refer to the pump's function curve), its undisturbed working pressure range is 760 ~ 60 mmHg. Therefore, the working point of the pump should be selected within this range, rather than allowing it to work for a long time under 25-30 mmHg.
3. Large vacuum pumps should be able to discharge all the gas produced in the process of vacuum equipment under their working pressure.
4. Accurate combination of large vacuum pumps. Because large vacuum pumps have selective pumping, sometimes a pump can not meet the requirements of pumping, several pumps need to be combined to complement each other in order to meet the requirements of pumping. For example, the titanium sublimation pump has a high pumping speed for hydrogen, but can not pump helium, while the tripolar sputtering ion pump (or the bipolar asymmetric cathode sputtering ion pump) has a certain pumping speed for argon, the combination of the two will make the vacuum device get a better vacuum degree. In addition, some large vacuum pumps can not work at atmospheric pressure, need pre-vacuum; some large vacuum pumps outlet pressure is lower than atmospheric pressure, need the front pump, so they need to be combined to use.
5. Requirements of vacuum equipment for oil pollution. If the equipment is strictly oil-free, all kinds of oil-free pumps should be selected, such as water ring pump, molecular sieve adsorption pump, sputtering ion pump, cryopump, etc. If the requirements are not strict, you can choose to have oil pumps, plus some anti-oil pollution measures, such as adding cold traps, baffles, oil traps, etc., can also meet the requirements of clean vacuum.
6. Understand the composition of the extracted gas. The gas contains no condensable vapor, particulate dust, erosion and so on. When choosing a large vacuum pump, it is necessary to know the gas composition and select the appropriate pump for the pumped gas. If the gas contains vapor, particles, and corrosive gas, it should be considered to install auxiliary equipment such as condenser, dust collector and so on in the intake pipeline of the pump.
7. How does the oil vapor from the large vacuum pump affect the environment? If the environment is not allowed to be polluted, large oil-free vacuum pumps can be selected, or oil vapor can be discharged outdoors.
8. Whether the vibration produced by large vacuum pump during operation has an impact on the process and environment. If the process is not allowed, vibration-free pumps should be selected or anti-vibration measures should be taken.