Diffusion pumps

Abstract

A combination including a diffusion pump and a reservoir for working fluid positioned remotely from the pump and connected to the diffusion pump via a valve and pipework.

What is claimed is:  
     
         1 . In combination, a diffusion pump, a reservoir for containing a working fluid spaced from the diffusion pump, and pipework means for allowing the flow of the working fluid from the reservoir towards the diffusion pump.  
     
     
         2 . The combination as claimed in  claim 1 , in which the reservoir includes a tank for containing the working fluid, the tank being provided with a transparent window for viewing the level of the working fluid within the tank.  
     
     
         3 . The combination as claimed in  claim 2 , further including a valve movable between a first closed position preventing the flow of the working fluid out from the tank to a second open position which allows working fluid to flow out from the tank towards the diffusion pump.  
     
     
         4 . The combination as claimed in  claim 3 , wherein the movement of the valve between said first closed position and said second open position is controlled by a level monitoring sensor.  
     
     
         5 . The combination as claimed in  claim 3  wherein the valve is a solenoid valve and the level monitoring sensor comprises a vertically mounted float and a reed switch, the level monitoring sensor being connected via said pipework means to ports on the diffusion pump.  
     
     
         6 . The combination as claimed in  claim 4 , wherein the valve is a solenoid valve and the level monitoring sensor comprises a vertically mounted float and a reed switch, the level monitoring sensor being connected via said pipework means to ports on the diffusion pump.  
     
     
         7 . The combination as claimed in  claim 5  further including an electronic timer circuit for providing a time delay in the movement of the valve from its second open position to its first closed position.  
     
     
         8 . The combination as claimed in  claim 6  further including an electronic timer circuit for providing a time delay in the movement of the valve from its second open position to its first closed position.