| Progressive Cavity Pumps |
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The progressing cavity pump principal comprehends a rotor mainly made of a steel alloy and a stator made out of rubber. The Stator is always manufacture with one more lobe than the rotor and the pair can have a 1:2, 2:3, 3:4, etc configuration. The rotor has an eccentric move when rotating, also receiving the name of eccentric screw pump. The eccentric rotor is joint by an Universal Joint, Flexible Shaft, Gear Joint, or cardan joint to the concentric rotating Shaft. Stators are normally made out of NBR, EPDM, Viton, and Natural Rubber; however, there are more materials available such as Teflon, and even metal. The rotors are normally made out of tool steel or stainless steel, and can sometimes have different coatings such as Duktil or hard chrome. Suctions housings are also normally made of cast iron or stainless steel depending on how corrosive the application is. The progressive cavity pump has the following advantages: -Reverse Flow -Low Shear -Positive Displacement -Self Priming -Low noise -Continuous Flow - No pulsating -Metering Capability -High Solid Content Progressive cavity pumps, also called helicoidal pumps, can be mounted Horizontally or vertically depending on the application. Stator and rotor sizes can be as small as a few inches to 20 feet in length. The length determines the stages on the pump. Applications of progressing cavity pumps vary. Sucker pumps are being replace mostly by progressing cavity pumps in the oilfield industry also called downhole applications. Surface applications are sludge and slurry transferring, animal waste and rendering, molasses, pulp and paper, pharmaceutical, chemical and explosives. Some drum pumps even use the progressive cavity principal. In food and sanitary application, the progressive cavity pumps are made to 3A standards and the construction is made in such a way that they can be assemble and disassemble easily for hygiene. |
