Roots pump compressed gas power and pressure difference is inversely proportional, once the gas pressure difference is too high, the pump can appear overload scene, forming motor winding burn. There are several important ways to deal with pump overload:

 

Adopt mechanical automatic pressure regulating bypass valve

The bypass valve is located in the bypass line between the outlet and inlet of the Roots pump. This valve controls the pressure difference between the pump inlet and outlet without exceeding the rating. When the pressure difference reaches the rated value, the valve automatically opens by pressure difference, so that the outlet of roots pump is connected with the inlet, and the pressure difference between the inlet and outlet drops rapidly. At this time, Roots pump operates under basically no pressure difference load. When the differential pressure is lower than the rating, the valve automatically closes and the gas is removed by the fore stage pump through the Roots pump. Roots pump with bypass overflow valve can be started at the same time with the front pump, making the unit operation simple and convenient.

 

Two, adopt hydraulic coupling

Hydraulic coupling can also avoid the overload phenomenon of the pump, so that the pump can work under the low pressure difference. The hydraulic coupling is arranged between the pump and the motor. Under normal working conditions, the hydraulic coupling transmits rated torque from the motor end to the pump. The maximum pressure difference of roots pump is determined by the maximum torque transmitted by the hydraulic coupling, and the maximum torque transmitted by the hydraulic coupling is adjusted by the amount of liquid in it. When the pump under the low pressure difference or with the front stage pump started at the same time, in the liquid coupling outside the rotation speed difference that slip, transfer only a certain torque, so that the pump to accelerate the work. With the extraction process, the gas load decreases, roots pump gradually accelerated to the rated speed.

 

Three, the use of vacuum electrical components control pump inlet pressure

Install vacuum capsule relay or electric contact vacuum pressure gauge and other pressure sensing elements in the inlet pipeline of Roots pump. After the vacuum system is started, when the pressure at the roots pump inlet is lower than the set value (the allowable starting pressure of the pump), the pressure sensor recovers the signal and opens the Roots pump through the electrical control system (if there is a roots pump bypass pipeline in the vacuum system, the bypass pipeline valve should be closed at the same time). If the pump inlet pressure is higher than the set value, it will automatically close roots pump (or close the pump bypass pipeline valve at the same time), so as to ensure the reliable operation of roots pump.