Vacuum pump unit selection scheme

Vacuum pump unit usually consists of the following components: various vacuum pumps; Vacuum measuring unit; Vacuum valve; Vacuum tube and some other components, such as blower, vacuum joint, gas storage tank, bellows, dust collector and vacuum relay.

According to the working pressure of the unit, there is a crude vacuum pump unit (> 1330Pa). Low vacuum pump unit (1330~ 0.13pa); High vacuum pump unit (0.13~1.3×10-6 Pa); Ultra-high vacuum pump unit (1.3×10-6) ~1.3×10-11 Pa; Very high vacuum pump unit (<1.2×10-11 Pa).

Roots vacuum pumps (mechanical booster pumps) used for high vacuum cannot be discharged directly into the atmosphere. For example, the inline atmosphere would cause the pressure difference between the inlet and outlet of the roots vacuum pump to be too large, thus overloading the roots vacuum pump. Increasing the power of roots vacuum pump motor will lead to overheating of roots vacuum pump. Therefore, the small gap between the rotors of roots vacuum pump will quickly become stuck due to thermal expansion. In order to ensure that the vacuum pump can achieve higher vacuum degree, must ensure the gap between the rotor of the vacuum pump. Therefore, the roots vacuum pump must be equipped with the front stage pump. When the pressure in the system is sent to a certain range through the front stage pump, the roots vacuum pump will be started to prevent the roots vacuum pump from overloading. The front pumps may be vacuum pumps that can be directly discharged into the atmosphere, such as water (liquid) ring vacuum pumps, rotary vacuum pumps, slide valve vacuum pumps or reciprocating vacuum pumps.

Roots vacuum pump unit under normal conditions, the use of water ring pump as a front stage pump has advantages over other vacuum pumps, mainly because it can remove a large amount of condensable steam, especially when the gas ballast mechanical vacuum pump eliminates condensation. Insufficient steam capacity, or solvents used can degrade the pump oil and affect performance, or especially when the vacuum system does not allow oil contamination.

The main characteristics of low vacuum pump set are high working pressure and large displacement, but the pumping speed is lower than that of high vacuum pump set. It is widely used in vacuum pumping and vacuum cleaning, vacuum impregnation, vacuum cleaning, vacuum degassing, vacuum drying and other equipment. The main pumps of the low vacuum pump unit are the commonly used reciprocating vacuum pumps, oil seal vacuum pumps, water jet pumps, water ring pumps, oil steam jet pumps, molecular sieve adsorption pumps and roots pumps. When using low vacuum pump units, components such as dust collectors and dry filters must also be configured according to the process requirements for the cleanliness and humidity of the pumped gas.

High vacuum pump unit such as JZJX, JZJP roots rotary vane vacuum pump unit.

1 choose the main pump, the main pump has diffusion pump, molecular pump, sputtering ion pump, titanium pump, cryogenic pump, etc.

2. Select pre-pumping pump and storage pipe (shockproof, shorten working cycle, prevent massive ventilation in vacuum room, and stabilize outlet pressure of diffusion pump)

Ultra high vacuum pump unit

The main pump has extremely high vacuum, low leakage rate, and is resistant to baking at temperatures of 200 to 450°C.

Diffusion pump unit: reduce backflow and control pollution;

2 molecular pump unit: hydrogen compression ratio is small, the residual gas is mainly hydrogen;

3 sputtering ion pump unit: usually used together with titanium pump;

Cryogenic pump unit: no pollution.

Due to the high cost of ultra-high vacuum pump set, the assembly structure is more stringent, and is now being replaced by roots rotary vane vacuum pump set. However, there is another quantitative requirement under the extremely strict work environment requirements.