ZJP series roots vacuum pump with overflow valve (referred to as the roots pump hereinafter) are positive displacement pumps with two symmetrically shaped impellers, shaped like the figure “8”, rotate in opposite directions inside the pump housing. Roots pump are generally used to increase the pumping speed and/or to reach a higher end-vacuum on the pump system.
Roots pumps are able to run at high rotation speed, as high as 1500~3000rpm, as the impellors are rotating non-contact. Due to the high rotation speed it is possible to have a high pumping speed with a relative small sized pump. It is possible to pump high quantities of gas in combination with a relative small backing pump. The energy consumption of such a system is much lower than of a single backing pump with the same pumping speed.
The by-pass valve is mounted between the inlet and the exhaust and controls the pressure difference by opening and closing the by-pass valve by gravity. When the pressure difference between the inlet and exhaust is too high the by-pass valve will open and protects the Roots pump from overheating. This way it is possible to run the Roots pump at the same time that the backing pump starts and achieving the maximum pumping speed, also at higher pressures.
There are two kinds of vacuum pumps, corrosion and anti-corrosion. The anti-corrosion roots vacuum pump is coated with Teflon or Ni-p by customer’s request. Also clients can choose skeleton oil seal or five point type oil seal by there own will.