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Pump Basics

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We offer portable pumps to provide rental solutions for most dewatering applications. To select the most suitable pump for your application, first consider the following factors:

  • Fluid Type—whether the fluid being pumped is clean or dirty, contains any solids or abrasives, or is a hazardous material.
  • Flow Rate—how many GPM (gallons per minute) of pump flow are required.
  • Hose Length—the suction and discharge hose lengths required. Longer hoses increase line friction, thereby reducing pump performance. Therefore, hose lengths should be kept as short as possible.
  • Suction Lift—the vertical distance from the surface of the fluid being pumped to the centerline of the pump impeller. This distance should be kept to a minimum for maximum pump performance.
  • Discharge Head—the vertical distance from the centerline of the pump impeller to the point of discharge.
  • Dynamic Head—includes the effect of line friction on suction lift and discharge head. Total dynamic head equals the dynamic suction head plus the dynamic discharge head.
  • Seepage—the rate at which the fluid being pumped accumulates at the point of suction. Slow seepage allows air into the pump suction, which causes some types of pump to lose their prime.

Basically, there are two categories of pumps utilized in construction and dewatering applications: centrifugal, which includes self-priming, trash, and submersible pumps; and positive displacement, which includes diaphragm pumps of various types. To determine the type of pump needed for your application, review the summary below of the types of small pumps and their primary applications:


Self-Priming Centrifugal Trash Pumps provide an efficient solution for applications where the suction lift is less than 25' and the discharge head is less than 100'. These rugged pumps are capable of passing up to 25% (by volume) small solids (particles of mud, sand, leaves, rocks, etc.), up to half the diameter of the suction port. Hence, a 2" trash pump can pass up to 1" diameter solids. Trash pumps also provide easy access to the pump body for cleanout should clogging occur.


High-Pressure (High-head) Pumps are designed for applications requiring a greater than normal discharge head. Although providing less flow (GPM), high-pressure pumps can typically operate with a discharge head two to three times greater than a comparably sized standard pump.


Diaphragm Pumps are ideal for applications involving slow seepage at the point of suction, due to their great air handling capabilities. Although slower and less efficient than centrifugal pumps, diaphragm pumps can operate in conditions where centrifugal pumps would lose their prime.


Electric Submersible Pumps consist of a centrifugal pump closely coupled to a watertight electric motor with a waterproof power cord. These pumps operate submerged, thereby eliminating the suction lift limitations of other types of pumps. Other features include quiet operation, no engine fumes, and continuous operation without refueling.


Hydrostatic Test Pumps are utilized to pressure test pipelines and pressure vessels in both underground and above ground applications.

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