How does API Pump Work? | API Pump Vs ANSI Pump

What is an API Pump?

API stands for American Petroleum Institute. This standard is used to design special types of pumps. An API pump is a type of pump designed to fulfill the API 610 Standard for hydrocarbon processing.

The API pumps have various types. These pumps use multiple pumping methods.

The API 610 standard is most usually used for centrifugal pumps, but API processing pumps come in a variety of types, including vertical turbo pump, vertical in-line pump, multistage pump, horizontal split pump, or suction pump.

API pump

The API pumps are specially used for the gasoline, petroleum industry, and other hydrocarbons in the oil industry. However, the API 610 standard is very traditional, and other industries may use API pumps to ensure a robust design.

Working of API Pump

 The API pumps are specially made to process hydrocarbons at very high temperatures and pressures that can ignite even if they accidentally leak. Therefore, the pump body has a high-quality design and manufacturing material to stop the leakage of hydrocarbons.

 In addition, the significance of the failure of this pump can mean high production losses for the owner. In simple words, the API pump is planned very conservatively in terms of bearing design, allowable shaft deflection, weldments, flange design, casing thickness, and more.

API 610 doesn’t allow some specific types of pumps because these types are not manufactured conservatively enough or cannot handle high pressures and temperatures.

This pump typically contains an explosion-proof motor and is powerful enough that it doesn’t need frequent maintenance. It always has a sealed impeller and a wear ring on the impeller. These impeller clamps or welds are employed to prevent slipping due to thermal expansion differences.

These pumps are planned to be supported by the centerline of the pump rather than the feet under the housing, allowing them to expand evenly around the centerline at high temperatures.

Components of API Pump

The API pump has the following components:

  • Mounting Feet
  • Bearing Housing
  • Pump Casing
  • Back Cover Arrangement

1) Mounting Feet

API pumps are most commonly employed in high-temperature services; therefore, the mounting feet must fulfill the desired expansion. ANSI pump mounting feet extend from the bottom of the housing and fix to the baseplate.

In contrast, the API centrifugal pumps are installed on the horizontal centerline of the housing instead of the bottom. The legs overhang from the side of the housing and are bolted to the base, which rises from the baseplate. In expansion conditions, the mounting feet apply nominal stress to the housing above and underneath the centerline of the pump.

2) Bearing Housing

API pump housing should have a stronger structure. It must also support the bearing cooling medium. This is usually done by using a cooling jacket that provides more cooling water.

3) Pump Casing

The casing of the API pump may have a single-volute design, but in most cases, it has a double-volute design to minimize thrust load around the shaft and impeller. These casings have the capability to withstand higher temperature and pressure and can handle polluting liquids in a better way.

4) Back Cover Arrangement

In the oil, gas, and petrochemical industries, the EPA requires emissions controls. The ANSI design back cover is arranged with a space between the coupling surfaces of the pump housing and the frame adapter to discharge hazardous gases.

The API design creates a tight seal with a compression seal that fits the metals together. This will help to emit the hazardous gases in a better way.

Read More: AODD Pump Working and Types

Applications of API Pumps

API pumps are used for multiple applications. API pumps are most commonly used in pipelines, oil production machinery, oil refineries, and other hydrocarbon processing plants. They also use in some other industries that require a very strong and conservative design, like the power generation industry.


API pump has more weight than the ANSI pump. Differences in the position of the housing, back cover arrangement, mounting feet bearing housing, and permit API pumps to handle the output. The API pumps have more reliability and efficiency in recommended services than the ANSI pumps.

The main difference between the API pump and the ANSI pump is given below:

An API pump is more costly than an ANSI pump.It is less expensive.
It has less flexibility.It is very flexible.
It is considered to be heavier duty than an ANSI pump.It is not a heavy pump.
API pump is best suitable for viscous fluids.ANSI pump is not ideal for thicker or viscous fluids.
It has more ability to bear temperature and pressure than the ANSI pump.It can’t bear higher temperature and pressure for a long time.
API pumps have more weight than ANSI pumps.  ANSI pumps are lightweight pumps.

Read More: Difference between Reciprocating Pump and Centrifugal Pump

FAQ Section

What is the full form of API for pump?

API stands for American Petroleum Institute. This standard is used to design special types of pumps.

What is the API 610 pump?

The API 610 BB pump is a “Between-bearings” pump in which the pump impeller is located on a shaft. The impeller is installed on the shaft via bearings at both ends. 

What is API standard for pumps?

API 610 is the specific API standard that pertains to centrifugal pumps and their associated systems.

What is API standard of pumps?

API standards play a crucial role in defining the design, testing, and equipment specifications primarily within the petrochemical, petroleum, and oil and gas sectors. Pumps that conform to API standards are known for their exceptional quality and are highly regarded in the industry.

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