Roots vacuum pump use and application

Roots Vacuum Pump Working Principle

Roots vacuum pump (hereinafter referred to as Roots pump) is a pair of interaction synchronous reverse rotation of the “8” shaped rotor to achieve the pumping function. When the suction chamber is formed between the rotor and the pump body, the two rotors are always sealed with each other to ensure that the exhaust gas does not flow back to the intake port, so as to realize the function of suction. The reverse synchronous rotation of the rotor is realized by a pair of gears mounted on the rotor shaft. Because there is no friction in the pump chamber, Roots pump can run at a high speed of 1500-3000 rpm without lubrication in the pump chamber. In addition, to keep the Roots pump running smoothly at high speed, a good dynamic balance of the rotor is needed. There is no direct contact between the high-speed rotating rotor, rotor and pump body, and there is a certain gap between the moving parts. A built-in relief valve is installed between the intake and exhaust ports of Roots pump. Its function is that when the pressure difference between the intake and exhaust ports reaches a certain value, the relief valve opens automatically, and part of the gas from the exhaust ports flows back to the intake ports through the open relief valve, which greatly reduces the operating load of Roots pump and the front vacuum pump (hereinafter referred to as the front pump) under the high pressure difference. At the same time, because the open relief valve has a strong discharge function, it can ensure that the Paulz pump and the front-stage pump can start at the same time without overloading the Roots pump and the front-stage pump, and can improve the pumping speed of Roots pump unit under high inlet pressure.

Roots Vacuum Pump Main Use

Roots pump is widely used in all aspects of vacuum acquisition. It extends the working range of oil-sealed mechanical vacuum pump under low inlet pressure. It has the characteristics of small volume and large pumping speed. It has large pumping speed in the range of 1-100pa inlet pressure. It is especially suitable for vacuum systems requiring large pumping speed under low inlet pressure, such as power transformer, power capacitor and power mutual inductance. Vacuum drying, vacuum impregnation, vacuum heat treatment, vacuum smelting exhaust, vacuum coating equipment pre-pumping, large test wind tunnel exhaust and lighting production line exhaust, etc. Roots pump can also be widely used in the vacuum distillation, concentration and drying process of food, chemical, pharmaceutical, textile and other industries if the appropriate front pump is selected.

Main Technical Performance Indicators of Roots Vacuum Pump (See Table below)

Model ZJ-150 ZJ-300 ZJ-600 ZJ-1200
Pumping speed(L/s) 150 300 600 1200
Ultimate pressure
1stage piston pump as backing pump 5×10-2
2 stage piston pump as backing pump 1×10-1
Max. allowable diff. pressure(Pa) 8×103 5×103
Motor rotary speed(RPM) 3000
Suitable motor power(kW) 2.2 4 7.5 11
Flange size Inlet(mm) 100 150 200 250
outlet(mm) 100 150 200 200
Cooling water consumption(L/h) 120 150
Allowable temperature(℃) 100
Vacuum pump oil 100#
Weight(without motor)(kg) 195 250 760 860

Roots vacuum pump installation instructions

4.1 Roots pumps shall be installed in dry, ventilated and clean places.
4.2 Roots pumps shall be installed horizontally, with a clearance of at least 300 mm between the wall or other objects. The oil window part of the pump should leave room for easy observation of oil level.
4.3 When switching on the power supply, attention should be paid to the motor steering. From the motor tail of Roots pump, the motor shaft should turn clockwise. Operating steps: Turn on the three-phase power supply of the motor, point the motor start button and check whether the steering is correct. If the steering is opposite, replace any two terminals of the three power supply terminals.
4.4 The pipeline connecting Roots pump and pumped container should be clean, dry and leak-free. The diameter of the pipeline should be as small as possible as the inlet of Roots pump. The length of the pipeline should be shorter so as to reduce the pumping speed loss. There should be no leakage at the junction of the pipeline.

Roots Vacuum Pump Products Pictures:

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