Canned Motor Pumps

What is a canned motor pump?

A type of pump designed to move fluids with absolutely no chance of leakage. They are considered an alternative to a magnetic drive pump that insures zero leakage, while at the same time eliminating the mechanical seal, which is often the most expensive component to maintain in a pump. This makes canned motor pumps ideal for pumping dangerous or difficult fluids such as radioactive coolant, very expensive heat transfer liquids that are prone to evaporation when pumped with conventionally mechanically sealed pumps, and extremely corrosive or noxious liquids. They are most commonly centrifugal pumps, but their design can also be incorporated into rotary positive displacement pumps.

How do they work?

The pumping mechanism consists of a motor that is close-coupled to the pump, with both components being contained in a hermetically sealed chamber that allows no leakage. The rotor of the motor is exposed to the liquid being pumped, as there is a circulation path of a portion of the pumped liquid through the motor rotor, to lubricate the sleeve bearings and thrust surfaces that are part of the pump and motor. This circulating liquid then returns to the pump end, where it is ultimately pumped out of the discharge of the pump. The stator of the motor is isolated from the liquid that is circulating through the rotor by a metallic can so that the motor stator remains dry. Since the sleeve bearings and thrust washers in the motor rotor must be lubricated by the circulating liquid, these bearings are made of hardened wear resistant materials such as silicon carbide or tungsten carbide.

Where are they used?

Canned motor pumps are used exclusively for toxic, noxious, or aggressive fluids. They may be used for water, but there would be no reason to do so. The leak-proof feature makes them ideal for use in the nuclear power industry, in the chemical industry, and in any other area where the fluid can't come into contact with the environment.

Here are some canned motor pump manufacturers to consider.

Expert Advice

Understanding a few key factors before buying a vertical turbine pump can prevent unnecessary maintenance costs. Author provides some advice when shopping for and installing the pumps motor, discharge head, bowl assembly, and column & lineshaft.

Though gear pumps may seem simple enough, properly sizing them can be complicated. Author suggests that it actually takes five pump curves to correctly size a gear pump.

Incorrectly installed suction and discharge piping can create stresses on the pump casing and thus reducing the reliability of the seal and bearings. Read tips on how to eliminate this occurance.

Read All

Industry Updates

Switch to: Expert Advice | Pump Tweets

Colfax Fluid Handling has created an online energy savings calculator for oil and gas industry pump applications, World Pumps reports. The calculator allows comparisons between centrifugal pumps and rotary positive displacement pumps in single and multiple pump applications.

The world's drinking water plants will spend just under $6 billion this year for pumps, according to a new report from the Mcilvaine Company.

Double hose-diaphragm pumps in quintuplex configuration guarantee minimum pulsation and wear. German pump manufacturer Feluwa's Multisafe double hose - diaphragms pumps make easy work of moving aggressive or abrasive products long distrance, according to a company news release.

Read All

Pump Tweets

Chilean pump manufacturer Neptuno Pumps has been awarded a contract to supply a dozen vertical turbine pumps for a reclaim water system project at a copper mine in Chile.

Colfax introduces an online energy savings calculator for oil and gas industry pump applications. The calculator allows head-to-head comparisons between centrifugal pumps and rotary positive displacement pumps in both single and multiple pump applications. Check it out at the Colfax website.

Frost & Sullivan has honored NETZSCH Pumps & Systems with the 2011 Best Practice Award for increased customer benefit. NETZSCH's customer focus and product innovation were a few key factors in winning the award. NETZSCH is a leading manufacturer of progressive cavity pumps, screw pumps, lobe pumps, metering pumps and other equipment.

Read All