Question

What type of pumps are used in hydraulic combinaton systems?
two-phase (two-step) or round pumps

Answer 1

We have three types maily.

1. Gear pumps

2. Rotary Vane Pump

3. Screw pumps

Coming to the first one, Gear pumps: (with external teeth) are simple and economical pumps. the swept volume or displacement of gear pumps for hydraulics wil be between 1 and 200ml. They have low volumetric efficiency. these pumps create pressure through the meshing of gear teeth which forces fluid around the gears to pressurize the outlet side.

Second one, Rotary Vane pump: ( Fixed and simple adjustable displacement) They have heigher efficiency than gear pumps. But are also used for mid presures upto 180bar. Vane pumps are not regarded as high pressure components. Forcing the vane out of the roatating centre and towards the pump housing is acomplished using spring loaded vanes or more traditionally vanes loaded hydrodynamiclly.

Third one, Screw pumps: (Fixed displacement Pumps) These consist of two archimedes screws that intermesh and are enclosed within the same chamber. these pumps are used for high flows at relatively low pressure. ( maximum 10bar). These were used on board ships especially to control ball valves. but also to help drive the steering gear and other systems.

Please find the images below for your better understanding.