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Centrifugal Pump
A basic centrifugal pump is a very basic piece of equipment in the oil field. It consists of a motor, casing and an impeller. A centrifugal pump converts rotational energy into pressure energy. This is accomplished by accelerating the fluid across the vanes of the pump's impeller.
There are several types of centrifugal pumps.
ANSI Pumps
The most common is the ANSI pump (in the US) and an ISO pump (everywhere else). An ANSI Pump is such that there is a standard set of dimensional standards that describe the dimensions of a back pull out, centrifugal pump. The reasoning of an ANSI pump is to standardize the footprint of a pump so that one may be pulled out and another put in its place.
ANSI Pumps are typically limited to a lower flow rate and head than an API pump. For most low pressure applications, this is the pump to use. However, just like everything else, be sure to consult the client's specifications prior to calling for an ANSI Pump. The same holds true for API Pumps.
API Pumps
Like an ANSI Pump, an API Pump (governed by API Standard API 610) is built to a standard set forth by API. API Pumps are generally larger and more robust pumps than ANSI pumps. As an ANSI pumps is for use in the chemical industry where API pumps are for use in the oil & gas industry.
For installation help, click on the Installation page.
For materials of construction, click on the Material of Construction Page.
Advantages
Centrifugal pumps have many advantages over other types of pumps. Among them are:
- Steady flow (No pulsation)
- Supplies the head (pressure) required by the system
- Excellent rangeability and controllability with a VFD or throttling valve
- Can handle most liquids with some solids
- Can be operated with totally blocked flow or shut off temporarily without damaging the pump.
- Standard design means parts are usually readily available
- Very reliable
Disadvantages
- Limited to low to moderate viscosity fluids
- Not to be used for oil water emulsion as this pump exerts shear forces on the fluid and may tighten the emulsion.
- Developed head is limited.
- Must be primed prior to start up (non self priming)
- Pumps are sensitive to NPSH
- Fluids with entrained gas may risk cavitation. (Always check vapor pressure when doing the NPSH calculation)
