Pumping operation of JRP series Roots effected through two ‘8’shaped rotors in pumping chamber rotating opposite directions. With drive ratio of 1:1,two rotors constantly seal against themselves without touting each other and the chamer. The gaps between the movabls parts are narrow enough to seal against the exhaust side and intake side in visous flow and molecular flow,so that to chieve the purpose of pumping the gas in the chamer. 
        When the rotors locate at 1 and 2 in the chamber,the volume of air inlet will increase. When the rotors locate at 3 in the chamber,part of air volume will be blocked out from the air inlet. When the rotors locate at 4,this volume will open to vent.When the rotors further,air will discharge through the air outlet. Rotors will rotors more than two coures once every rotates.
       The pressure difference between the inlet side and outlet side of roots pump are limited. JRP series roots pump adopts a bypass valve.When the value of pressure difference reaches to a certain figure,the bypass valve opens automatically.Some air volume from the outlet side flows to the reverse direction of inlet side through the bypass valve and reverse passage,which reduce the operational load of roots 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 JRP series vacuum pump and front-stage pump start at same time to aviod the overload for both of them.
       The roots pump has to be worked as pump unit together with front-stage pump(such as rotating vane pump,slide valve pump and liquid ring pump).If it is required to reach to higher vacuum degree,two sets of roots pumps can be connected to work as a three stage roots pump unit.