Jet pumps are a kind of dynamic friction pump. These units do not have rotating parts, causing fluid moves due to the friction that occurs between it and the working fluid flows. The function of a jet pump is pumping viscous liquids and gases by the kinetic energy produced by steam or water.

Water-jet pump uses water as the working fluid. It is fed at high speed from a nozzle into a mixing chamber, and then enters into the diffuser. In the process, the working fluid by means of friction force entrains the liquid to be pumped.

The fluid enters the mixing chamber from the suction line due to the pressure difference directly into the mixing chamber and diffuser. In the latter, the flow rate decreases, and the pressure energy is growing. As a result of these processes, the substance under pressure is supplied to the discharge pipe.

Steam pump jets are indispensable in cases where the substance cannot be pumped, mixed with water, which is formed when the condensate (ie the supply of water in steam boilers).

Jet Pumps: existing types

There are three types of jet pumps, depending on the types of substances which are pumped, and which uses a working fluid:

• Ejector (working and pumping material are liquids);
• The elevator (the working fluid is a substance or a liquid pumping pulp with another temperature level);
• Injector (working medium is steam and pumped liquid substance).

Jet Pumps: Design features and principle of operation

The high pressure jet pump has a simple construction, thus it requires little maintenance and has a high degree of reliability. The principle of operation is based on the fluid flow, vapor or gas through a pipe with a nozzle which tapers (liquid thereby moving at high speed). In the inlet chamber is maintained below atmospheric pressure level. Suction is from the pipeline, which is connected to the camera. Then, the liquid and mixed together in the second chamber, after which the mixture falls in the diffuser and into the reservoir.

The main parameter is the ratio of the jet pump suction, which is determined by the ratio of the working fluid volume and pumped substances. In this type of pump low efficiency, but despite this, they are absolutely indispensable in some cases. Thus, in the food industry, jet pumps are used when it is necessary to pump fluid from the reservoir and it is impossible to use a different type of units.

Jet pumps are often used as an optional extra, because they are easy to install with other types of pumps:

• in sewer systems;
• fire fighting;
• in a single blade system with pumps to enhance effectiveness;
• in a single system with a centrifugal pump for pumping air into them before starting the work.

In rare cases, jet pumps are operated with the pressure vessel, where the active substance. These units are also considered as part of the heat pump, as feeding of low pressure steam occurs in the nozzle temperature level decrease, and when the high pressure flow – diffuser heated. Due to this, the jet pumps are used in air conditioning systems.