HYDRAULICS PUMPS

PUMPS

Pump is a device to induce fluid flow from one place to another place under pressure, hydraulics systems pumps are used to develop very high pressure to transfer energy from one place to another place.

Pumps are classified in many ways however they are classified as its way of mechanical working arrangement, fluid working principle and by its delivery

BY MECHANICAL OPERATION 

1. ROTARY PUMPS

2. SEMI ROTARY PUMPS

3. RECIPROCATING PUMPS

BY WORKING PRINCIPLE

1. DYNAMIC PRESSURE PUMP

2. POSITIVE   DISPLACEMENT  PUMP

BY DISCHARGE

1. CONSTANT DISCHARGE PUMP

2. VARIABLE DISCHARGE PUMP

3. VARIABLE AND REVERSIBLE DISCHARGE PUMP

ROTARY PUMPS

                A rotor or an impeller rotates inside housing and induces the fluid flow and pressure centrifugal pump, gear pump, vane pump, screw pump, axial and radial piston pump are rotary pumps suction and discharge valves are not employed in rotary pumps

SEMI ROTARY PUMP

                The rotor or its kind arrangement inside a housing moves only a less than half a circle in both the direction it is a hand operating pump. The flap valve arranged on the rotor is used for suction and delivery.

RECIPROCATING PUMP

                Piston pump and plunger pump are reciprocating pumps either it can be operated by hand or any other power this pumps are provided with suction and discharge valves. The suction valves are opened by suction pressure and the delivery valves are opened by fluid pressure. Small hand operated   reciprocating plunger pumps are used in hydraulic system for hydraulic jack, puller and pressure testing etc.

DYNAMIC PRESSURE PUMP

                In dynamic pressure pump a tangential acceleration is imported to the fluid and due to the movement of the fluid from centre to outer track, vacuum is created at the centre this vacuum is continuously filled with the fluid from the suction side because of atmospheric pressure or any other pressure. The tangential acceleration is imported to the liquid by centrifugal force. Centrifugal pump is a dynamic pressure pump. Mostly this type of pumps are used to transfer the fluid from  one place to another

POSITIVE DISPLACEMENT PUMP

                In positive displacement pump one or more chambers are filled while crossing suction port and the fluid is carried over and discharged at the discharge port by the chambers. This type of pump can develop high pressure. Vane   pump, gear pump, screw pump, axial and radial piston pump are positive displacement pumps

CONSTANT DISCHARGE PUMP

                All the positive displacement pumps are made as constant discharge pump. In this type of pump discharge fluid is always constant at particular rpm. The revolution is increased the discharge of fluid also increased and vice versa. gear pump, vane pump, axial piston pump, radial piston pump, screw  pump etc.

VARIABLE DISCHARGE PUMP

                In variable discharge pump the fluid discharge can be varied at given speed. Radial and axial piston pump vane pump are variable displacement pumps, a hand wheel or lever provided in this pump to alter the stroke length of the piston the quantity of discharge can be reduced or increased at a given speed by moving the lever or hand wheel 

VARIABLE AND REVERSIBLE DISCHARGE PUMP

                The quantity of discharge and direction of flow can be changed .in this type pump without altering the speed and direction of pump. The axial and radial piston pumps are examples the lever provided the pump control the stroke of the piston when the lever is neutral or center there would be no suction and discharge, when the lever is moved to right off center the pump begins to deliver the fluid through the one port and takes suction from other port, the lever is moved to opposite side off center the pump changes or reverse the direction of fluid