25-08-2017, 09:32 PM
Selecting Your Pump
Selecting Your.pdf (Size: 85.99 KB / Downloads: 27)
Piston vs. Plunger
We supply both piston and plunger designed pumps. The pressure and flow performance of these pumps can overlap requiring you
to either select a piston pump or plunger pump.
A piston pumps’ high pressure seal reciprocates with the piston in a cylinder. The intake is configured to allow smooth continuous flow at the intake. The inlet
valves are mechanically actuated and don’t rely on pressure differential to
operate. These factors reduce the risk of pump cavitation. Piston pumps are
capable of drawing their own liquid. The inlet pressure range of a piston pump is -
8.5 psig to 40 psig for proper operation. Piston pumps work in an output pressure
range from 100-1200 psi.
Duty Cycle
The amount of time (hours/day) a pump is operational defines its duty cycle. Continuous duty operation refers to a pump operating
the majority of the day. Larger pumps running slower will have a longer maintenance interval than a smaller pump running at full
speed in continuous duty applications. Cat Pumps defines continuous duty as a pump running under a full load or cycles 8 -24
hours/day, 5 – 7 days/week. Intermittent duty operation refers to a pump operating for brief periods during the day (i.e., jetting or
pressure washing applications). More aggressive liquid characteristics (i.e., low lubricity Deionized water, liquids being pumped at
high temperatures) will impact pump duty cycle selection.
Liquid Properties
Pumping liquids with suspended solids is not recommended. Solids can become trapped in valves and other components causing
malfunction. Cat Pumps does offer stainless steel submersible centrifugal pumps that can handle larger suspended solids (up to
3/8”).
Some liquids will contain abrasive solids. Abrasion can come from harsh mineral conditions of water (i.e., hard water, dirty water,
gritty water, reclaim water) causing excessive wear of pump components. Water softeners can reduce hard water conditions. Inlet
filters and settling tanks can help with dirty, reclaim or gritty water conditions.