Metering / Dosing Pumps

SHTP RECIPROCATING POSITIVE DISPLACEMENT PUMP

Definition:
A Reciprocating pump is a positive displacement pump or P.D. Pump. A Positive Displacement pump is one, which traps a fixed volume of liquid at suction (inlet) conditions, compresses it to discharge pressure and pushes it out through the discharge nozzle. This pumping action is accomplished by the reciprocating action of piston, plunger or diaphragm. This pumping action is further assisted by a check valve on the discharge side of each pump element and one on the suction side to prevent the back flow of the liquid from the discharge line to the suction line.
The Triplex Plunger Pump has a fixed stroke crankshaft similar to an automobile crankshaft and capacity can be varied only by increasing or decreasing the RPM of the crankshaft.
The Metering Pump is a Positive Displacement Metering Machine with the ability to change its capacity manually or automatically as the process conditions continuously change. This is done by a variable eccentric crank mechanism where the stroke length can be increased or decreased thereby increasing or decreasing capacity.

Advantages:
The Reciprocating Pump is not a kinetic machine, as is a centrifugal pump because it does not require velocity to achieve pressure. High pressures are achieved at low velocities and therein lie one of the advantages of the reciprocating pump.

Possibly the best characteristics of the power pump is its inherently high mechanical efficiency. Overall efficiencies normally range from 85% to 95%. The approximate loss of 10% includes all losses of belts, gears, bearings, packing and valves. This means approximately 90% of the power delivered by the driver is converted into liquid power.

Another characteristic of the reciprocating pump is that its capacity is proportional to speed and is relatively independent of discharge pressure.

The Metering Pumps high level of accuracy and repeatability makes it a reliable partner in any chemical process.