Most industries use vacuum units, so what are the types of vacuum pump system, and how to select the combination? Vacuum unit is generally named according to the type of main pump, such as water ring vacuum unit, water ring roots unit, screw vacuum unit, etc. it is classified according to the product characteristics, such as oil-containing vacuum unit and oil-free vacuum unit; common is that it can be divided into low vacuum unit, medium vacuum pump unit, high vacuum unit and ultra-high vacuum unit according to the use scale of vacuum, as follows Let’s get to know.
Vacuum pump system type:
1. Low vacuum unit
It is widely used in vacuum transportation, vacuum impregnation, vacuum filtration, vacuum degassing and so on. The main pumps commonly used in low vacuum units, reciprocating pumps, water ring vacuum pumps, oil seal mechanical pumps, screw vacuum pumps, roots vacuum pumps, jet pumps, molecular sieve adsorption pumps and other direct discharge atmospheric vacuum pumps can be used. However, according to the cleanliness, humidity and other conditions of the extracted gas, it is necessary to equip dust remover, gas-water oil-water separator, dry well, etc Equipment.
2. Medium vacuum unit
It is suitable for various vacuum systems with high pumping speed and medium vacuum, such as coating machine, vacuum smelting, vacuum heat treatment, medicine and chemical industry, electric welding and other professions. In the past, most vacuum units were composed of Roots vacuum pump + oil seal mechanical pump, roots vacuum pump + water ring vacuum pump and double roots vacuum pump. With the rise of oil-free vacuum pump such as screw vacuum pump, the oil-free vacuum unit such as roots vacuum pump + screw vacuum pump has gradually increased, with wider adaptability.
3. High vacuum unit
Under the molecular flow condition, the working pressure range is 10-2 ~ 10-6pa, the displacement is small and the pumping speed is large. In general, the main pump is borne by diffusion pump, molecular pump, titanium booster pump and low-temperature condensate pump. Because they can’t work directly in the atmosphere, they must be equipped with pre pump, pre pump, etc. in particular, in order to prevent the air pressure from shaking, they need to be equipped with maintenance pump and air tank And so on.
4. Ultra high vacuum unit
The operating pressure range is 10-6 ~ 10-10pa, and the limit vacuum of the main pump is required to be more than 10-7 ~ 10-8pa, and the corresponding pumping speed shall be ensured within the operating pressure range, such as sputter ion pump, turbine molecular pump, etc., and the data of system composition shall be able to fully experience high temperature baking of 200 ~ 450 ℃ and ensure low air leakage rate and air outlet rate.
How to select the vacuum pump system:
1. Vacuum pump combination, the functions of various vacuum pumps are different, so sometimes one pump is not satisfied with the pumping requirements. Several pumps are required to be combined to make up for each other to meet the pumping requirements.
2. In the selection of vacuum pump, when selecting the main pump, the working process environment of the main pump should be selected correctly. Within its working pressure scale, it should be able to clean up all the gas generated in the process of the vacuum chamber. Therefore, the working pressure in the vacuum chamber must be within the optimal pumping pressure scale of the main pump.
3. In the selection of vacuum pump, the volume of the vacuum chamber has an effect on the time when the system reaches the limit vacuum. When the time of pumping is required to be punctual, the larger the volume of the vacuum chamber is, the larger the pumping speed of the main pump is.
4. When selecting a vacuum pump, you should know the composition of the gas to be pumped, and select the corresponding vacuum pump according to the composition of the gas to be pumped. If the gas contains corrosive gas, particle dust, etc., dry vacuum pump, corrosion-resistant vacuum pump, etc., or auxiliary equipment shall be installed on the air inlet pipe of vacuum pump.
The combination and selection of vacuum pump must be careful. Generally, the selection of the ultimate pressure of the main pump is half to an order of magnitude lower than that of the vacuum chamber. More importantly, the main vacuum pump should be selected according to the economic indicators such as the initial investment and daily maintenance cost of the whole vacuum system. If you don’t understand, you can let the special vacuum engineering company make the selection plan.