Jet Pump Working Principle and Theory

When the level of underground water becomes quite down we use a Jet pump. Because in that case centrifugal pump or other rotary pumps cannot lift the water from that down level.

The working principle of this pump is somewhat different from that of the centrifugal pump or other types of rotary pumps. The working principle of a jet pump depends on the Bernoulli theory.

In a jet pump, water is pushed in a pipe with high pressure. There is a nozzle at the opening of the pipe. The shape of the nozzle is like a cone. When water comes out through the narrow opening of the nozzle with the high pressure the potential energy of the water becomes kinetic energy. Because of that, the pressure surrounds the nozzle reduces. This phenomenon facilitates the section of the inlet water.

We have to place the nozzle of the jet pump very nearer to the water level. Then we immerse the suction pipe of the pump in the water.

Jet Pump

In the industrial Jet pump, instead of using a water jet, we use the steam jet. So, there are two sources of water. The main water comes due to the suction of underground water. The jet water comes from the separate reservoir used to supply the jet water or steam. The total delivery of the jet pump is the summation of these two quantities of water.

Advantages of using a Jet Pump

It is quite possible to lift water from a very down level of underground water.

The quantity of lifted water depends on the size of the jet.

There is no moving part in a jet pump.

The pump does not require any prime mover because it does not have any rotating parts.

Frictional losses in the pump are quite low.


The delivery rate of this pump is quite low compared to other conventional pumps.

This type of pumping system always requires two pipes under the ground. This is because the pump needs to have an additional pipeline for providing water or steam supply to the nozzle in the suction chamber.

The jet pump system also requires an additional pumping system for providing water to produced jet in the suction chamber. This additional pumping system has to pump continuously the water at high speed and pressure during the operation of the pump.

Applications of Jet Pumps

We often use these pumps during high summer for lifting water from a low underground water level.

We find the maximum uses of jet pumps in oil industries for lifting mineral oil.

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