Step 1: Centrifugal pumps.
These pumps employ a rotating Impeller to propel fluid via centrifugal force. \[P \Rightarrow 2\]
Step 2: Reciprocating pumps.
Their operation relies on the linear, back-and-forth movement of a piston connected to a Piston rod. \[Q \Rightarrow 1\]
Step 3: Rotary pumps.
These utilize a rotating Gear or comparable component for positive displacement fluid transfer. \[R \Rightarrow 3\]
Step 4: Impulse pumps.
This category encompasses the Hydraulic ram, which leverages water hammer effects for pumping operations. \[S \Rightarrow 5\] \[\boxed{P-2, \ Q-1, \ R-3, \ S-5}\]