Multistage Pump

Multistage Pump, Multistage Centrifugal Pump, High Pressure Pump, Booster Pump, Boiler Feed Water Pump

A centrifugal pump containing more than impellers is called a multistage centrifugal pump.  Multistage centrifugal pump can be vertical type of horizontal type. The impellers may be mounted on the same shaft or on different shaft. If require higher pressures at the outlet, impellers can be connected in series. For higher flow output, impellers can be connected parallel. A common application of the multistage centrifugal pump is the RO Water Plant, Pressure Boosting System, boiler feed water pump. All energy transferred to the fluid is derived from the mechanical energy driving the impeller. This can be measured at isentropic compression, resulting in a slight temperature increase (in addition to the pressure increase). Multistage centrifugal pump can be horizontal or vertical.

How Does A Centrifugal Pump Work? A few basic characteristics of the centrifugal pump are listed here in order to make the functioning more understandable:

  • The centrifugal pump is a rotodynamic pump and works by creating kinetic energy.
  • Its main component is the impeller, which is actually the driving force behind the creation of kinetic energy.
  • These are capable of discharging large amount of fluid being pumped.
  • The impeller of the centrifugal pump is available in both straight vanes and curved vanes to suit the pumping requirement as the case may be.
  • The centrifugal pump is not a self-primed machine. It needs to be filled with liquid first and then set to operate.

There is another type of centrifugal pump available, which has two or more impellers assembled with it. This type of the centrifugal pump is known as the multistage centrifugal pump. The design structure although may differ. The impellers may use either a single shaft to mount impellers over, or it may have different shafts as well. Following is the working principle of the centrifugal pump:

  • Similar to all other pumps, the centrifugal pump also converts one form of energy into another form to operate for pumping fluid.
  • It principally takes mechanical energy from the motor assembled with the pump, and converts it into either kinetic energy or the potential energy of the fluid movement.
  • It absolutely depends upon the fluid as to what energy mechanical energy convert into. For example, when the fluid is lifted above and against the force of gravity, the form of energy changes from mechanical to potential. Likewise if the fluid experiences change in its pressure, even then the form of energy changes, but this time it changes from mechanical to kinetic energy.
  • Modern centrifugal pumps, however, work on a slightly different mechanism. The impeller, as indicated earlier, is available in both straight and curved blades/vanes. These curved blades are used by the impeller to exert an outward force over the fluid. Impeller is actually a spinning component and plays the vital role in pushing the fluid outside.
  • In response to this outward force upon the fluid, the fluid also starts circular motion. The continuous rotation of the fluid creates a pressure within the impeller and this rise in pressure transfers some amount of energy to the discharge end too.
  • Eventually when the pressure of the discharge end increases, the fluid is forced to move out via the discharge end and thus one pumping cycle is completed.

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