Relationship and difference between ZJ&ZJP

Both EVP ZJ and ZJP belongs to roots pump. They are same in pumping principal, working curve and application.

Pumping principal:effect through two”8”?shaped rotors in opposite direction to reach suction and exhaust.
Schematic diagram as below:

Feature of roots pump: The roots pump has to be worked as pump unit together with frong-stage pump(such as rotary vane pump, piston pump, liquid ring pump and so on).

Woking performance curve as below:

Application of roots pump:
The pump is widely used in vacuum coating, chemical, food, medicine, smelting, motor manufacturing and other industries. Especially when its front class pump uses a two-stage water ring pump, it can extract the other with a lot of water vapor, so it is very suitable for distillation evaporation,freeze-drying and other production processes.

The only difference between ZJ and ZJP is that there is by-pass valve for ZJP but no by-pass valve for ZJ. Schematic diagram is as below:

Function of by-pass valve: the pressure difference between the inlet side and outlet side of roots pump are limited. ZJP series roots pump adopts a by-pass valve. When the value of pressure difference reaches to a certain figure, the by-pass valve and reverse passage, which reduce the operational load of toots pump and front-stage pump greatly in the condition of high pressure difference. Meanwhile, due to the function of unloading when bypass valve opens, it makes sure ZJP series vacuum pump and front-stage pump start at same time to avoid the overload for both of them.

Tags: Roots vacuum pump

Edited by Nancy Zhang / EVP vacuum solution