Compressor

A compressor is an example of Turbomachinery that converts mechanical energy into hydraulic energy by outputting 'energised' fluid. The rotating part is called the impeller.

Pumps Classification
There are several types of pumps but here are the two main:

Positive Displacement Pumps (PDPs) work by letting fluid enter a chamber, closing it, and then squeezing the water out. Like a water bladder. The flow is constant despite changes of system pressure and a higher viscosity fluid increases the flow rate.

Rotodynamic Pumps (or Centrifugal Pumps) are pumps where the incoming fluid is sent to the base of the impeller and then through rotating the curved blades the water is shot out. Watch this to understand. The blades rotate faster and add rotational momentum to fluid. Higher system pressure and higher fluid viscosity decrease flow rate.