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About Pumps

Pumps are commonly used to move water or other liquids from point A to (a usually higher) point B. They can be used to dewater flooded construction sites and basements, as well as remove sewage and sludge as part of disaster relief efforts. The oil and gas industry uses pumps to circulate well drilling muds and industrial fluids. On a larger scale, pumps can drain ponds and even bypass rivers and dams.

Pumps come in stationary models, portable models, and towed units that can be moved from place to place as needed. There are electric pumps and those that run on diesel, gasoline, hydraulic pressure, or compressed air.

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Wacker Neuson PT4A Trash Pump

Types Of Pumps

Many units in this category are clear water pumps that are suitable for potable water, thin chemicals, and stormwater without significant quantities of leaves, sticks, or other debris. These are often centrifugal or rotodynamic pumps, variations of which may have vortex impellers or radial- or axial-flow designs. So-called “non-clog impellers” and “semi-open impellers” can help pumps like these pass small solids without damage.

Other types of pumps, called “trash pumps,” are able to handle water with stones and other larger solids suspended in it without getting clogged. Many of these are positive-displacement units such as a diaphragm pump, rotary pump, or reciprocating pump. Other types of positive displacement designs include gear, lobe, peristaltic, and screw pumps. Users often turn to positive-displacement pumps to handle mud and other thick liquids.

A wet-prime pump must have its cavity filled with water or other liquid before it can begin to operate. If the intake hose or pipe introduces air into the suction stream, the pump may need to be re-primed before it can resume operation. A wet self-priming pump is a variation on this design that can slowly recover from a loss of suction due to cavitation.

A dry-prime pump uses a mechanism to quickly prime itself. The automatic priming device can be a vacuum pump unit, an air separator, a diaphragm, or a compressor paired with a venturi eductor to create rapid suction.

Other types of pumps include submersible pumps, vane pumps, progressive cavity pumps, column pumps, duplex and triplex mud pumps for drilling, mist pumps, dredging pumps, and air pumps. There are even pumps that can pull solid objects, such as ropes, which makes them a great fit for forestry, mining, and other industries.

Ratings

Pump capacities vary greatly. A portable model for light jobs may flow less than 170 gallons per minute (644 liters per minute), whereas a large column pump might be capable of pumping 20,000 gpm (75,700 l/min). Many pumps also have a rating for the maximum solids size they can digest, such as 0.4 inches (10.2 millimeters) for small pebbles or 3 in. (76 mm) for bigger rocks.

The diameter of pumps’ inlet (suction) and outlet (discharge) pipes or hoses likewise cover a large range. Small, portable pumps may have 2-in. (51-mm) inlets and outlets; contractor-level trash pumps may have 4- or 5-in. (102- or 127-mm) suction and discharge pipes; and larger stationary pumps can have 10-in. (254-mm) or even 16-inch (406-mm) inlets and outlets. Their flanges may accommodate pipes with thread types such as NPT (National Pipe Thread Taper), ANSI (American National Standards Institute), ANSI Spool, and DIN Spool (Deutsches Institut für Normung).

Pumps are also rated for their maximum suction lift and maximum discharge head. Maximum suction lift is the greatest vertical height from the surface of the water that the pump inlet can pull liquid, as in 25-foot (7.62-meter) suction lift. Maximum discharge head, meanwhile, is the highest vertical height from the surface of the liquid to the end of the outlet hose or pipe at which the pump can still output water, such as less than 40 ft (12.2 m) to more than 150 ft (45.7 m). The two measurements indicate how powerful the pump is. Along with friction losses from the liquid moving through the hose, the two can be calculated together to determine a pump’s total head.

Finally, like many other types of equipment, pumps often have hour meters to track their maintenance intervals. Some are also rated to handle liquids of certain temperatures, such as water of up to 120 degrees Fahrenheit (49 degrees Celsius).

Find The Right Pump For Your Application

There are many manufacturers of pumps large and small, but some of the more common brands on MachineryTrader.com include Gardner-Denver, Godwin, Gorman-Rupp, Honda, Multiquip, Thompson, and Wacker Neuson.