Steam driven water
pumps take many forms and a classic configuration is the Fire
Engine Pumper. Mr. Jim Murray, retired F.D.N.Y. and a close
personal friend of Richard Curt Nepper, the last owner of the Ahrens-Fox
Fire Engine Co. has graciously provided us with a copy of his
presentation with his photo gallery as presented to the Fire Museum of
Maryland in 2011. The photos are from the personal collection of both
Mr. Nepper and Mr. Murray.
presentation Mr. Murray refers to three pump types used at
Ahrens-Fox. They were the rotary, the piston, and the centrifugal pump.
A rotary pump, shown to the right, is a positive displacement pump using
either a single rotor (vane, piston, progressing cavity, screw, or
peristaltic) or multiple rotor (gear, lobe circumferential piston, or
screw). A reciprocating pump is either a piston, a plunger or a
diaphragm. Centrifugal pumps differ from rotary pumps in that they rely
on kinetic energy rather than mechanical means to move liquid. Liquid
enters the pump at the center of a rotating impeller and gains energy as
it moves to the outer diameter of the impeller.