PUMPS CLASSIFICATIONS AND QURAYYAH POWER PLANT PUMPS

Introduction

A pump is a device used to move gases, liquids or slurries. A pump moves liquids or gases from lower pressure to higher pressure. Technically, a pump is a unit used for transportation of liquids, fluids and gases through pipes or similar channels. The functionality of pumps is very simple; it consists of a suction mechanism at one end where the material is drawn in. Counter pressure is developed at the other end which forces the material out.

Pumps Classifications

Pumps are classified as mentioned in below diagram

Positive Displacement Pump

Positive Displacement Pump is one in which a definite volume of liquid is delivered for each cycle of pump operation. Positive Displacement Pump differs from Centrifugal Pump, which deliver a continuous flow for any given pumps speed and discharge resistance.

 Positive Displacement Classification 

Reciprocating Pumps

In a reciprocating pump, a volume of liquid is drawn into the cylinder through the suction valve on the intake stroke and is discharged under positive pressure through the outlet valves on the discharge stroke.

Piston Type

Piston pumps use a cylindrical mechanism to create a reciprocating motion along an axis, which then builds pressure in a cylinder to force gas or fluid through the pump. Piston pumps are used in lower pressure applications.

                                                              Piston Pump

Plunger Type

Plunger Pumps are very similar to Piston Type and can be either vertical or horizontal acting. The different between Plunger pump and Piston pump that the Plunger pumps do not have piston rings, but are sealed only where the plunger penetrates the casing

                                                   Plunger Pump

Diaphragm Type

A diaphragm pump is a positive displacement pump that uses a combination of the reciprocating action of a rubber or Teflon diaphragm and suitable non-return check valves to pump a fluid.

                                                              Diaphragm Pump

Rotary Pumps

Positive displacement rotary pumps are pumps that move fluid using the principles of rotation. The vacuum created by the rotation of the pump captures and draws in the liquid.

                                                      

Gear Type

A Gear pump uses the meshing of gears to pump fluid by displacement & commonly used for hydraulic fluid power applications. Gear pumps are fixed displacement, meaning they pump a constant amount of fluid for each revolution

                                                       External gear pump

Screw Type

Screw pump is one of the oldest types of pump. It is a kind of rotary, positive displacement pump that has one or more screws to transfer high or low viscosity fluids along an axis.

                                                      Screw Pump

Lobe Type

Lobe pumps are positive displacement pumps that use rotating lobes to direct flow. Lobe pumps are similar to gear pumps in operation in that fluid flows around the interior of the casing.

   Lobe Pump

Kinetic pumps

Kinetic Pumps transform fluid kinetic energy into fluid static pressure energy. Centrifugal Pumps are good example of this type of pump.

Centrifugal Pump

A centrifugal pump is a rot dynamic pump that uses a rotating impeller to increase the velocity of a fluid. The fluid enters the pump impeller along the rotating axis and is accelerated by the impeller, flowing radially outward into a volute chamber, from where it exits into the downstream piping system. 

                                                      Centrifugal pump

Axial Flow Centrifugal Pump

Mixed Flow Type

These pumps borrow characteristics from both radial flow and axial flow pumps

 Mixed Flow Centrifugal Pump

Jet Pumps

A jet pump is a combination of a volute centrifugal pump and a nozzle-venture arrangement. The driving force lifting the water in this type of pump is provided by a high pressure nozzle which creates a low pressure region in a mixing chamber. This low pressure causes water to flow into the pump.

 jet pump

Air-Lift Pumps

Air-lift pumps operate on the principle that a mixture of air and water will rise in a pipe surrounded by water. An air-lift pump basically consists of a vertical pipe partially submerged in water and an air supply tube allowing compressed air to be fed into the pipe at a considerable distance below the static water surface. The mixture of water and air is lighter than the water outside the pipe and it rises in the pipe.

     Air-lift pumps

Hydraulic Ram Pumps

A hydraulic ram pump is a motor less low flow rate pump. It uses the energy of flowing water to operate. It is suitable for use where a large flow rate is not required. The flow rate of typical commercially available units is limited to approximately 14 gallons per minute.

                                                             Hydraulic ram pump

Regenerative Turbine Pumps

There are two types as mentioned below

Overhung Impeller Type

Overhung Impellers are mounted on the extreme end of the shaft in a cantilevered condition hanging from the support bearings.

Impeller between Bearings Type

The impeller (or impellers) is mounted on a shaft with bearings at both ends. These pumps are further separated as single stage and multistage configurations.