Reciprocating pump piston/plunger

Reciprocating Pumps There are three classes of reciprocating pumps piston pumps, plunger pumps, and diaphragm pumps. 

In a piston reciprocating pump, the plunger piston is in direct contact with the solvent, so that the dead volume, i.e., the volume of the chamber that is not swept by the piston at the maximal stroke, can be very small. 

The most widely used pumps in the oil and gas industry are reciprocating displacement pumps (in particular piston plunger type), the rotary displacement pump, and the centrifugal dynamic pump. Only these pumps will be discussed in detail. 

The capacity of a pump is determined by the number of plungers or pistons and the size of these elements (bore and stroke). A reciprocating pump is usually designed for a specific volumetric rate capacity and pressure capability. These factors are set by the application. Once the volumetric rate capacity and pressure capability are known, a designer can determine the plunger piston bore and stroke the rotation speed range and the power of the prime mover needed to complete the system. 

Several methods have been used to produce the pulse action required in these columns. A reciprocating, plunger pump, from which the valves have been removed, may be connected to the extractor as at (a), Fig. 12, with a direct liquid connection between the column and the pump piston. Such an arrangement is perhaps mechanically most reliable, al-... 

FIGURE 6.3 Schematic representation of a piston reciprocating pump. 1 = rotating element attached to the plunger (movement indicated by empty arrow) 2 = piston 3 = inlet check valve. 

In the first major class of pumps a definite volume of liquid is trapped in a chamber, which is alternately filled from the inlet and emptied at a higher pressure through the discharge. There are two subclasses of positive-displacement pumps. In reciprocating pumps the chamber is a stationary cylinder that contains a piston or plunger in rotary pumps the chamber moves from inlet to discharge and back to the inlet. 

In a reciprocating pump, the movement of a plunger piston causes suction of the solvent during the backward stroke and delivery of the pressurized solvent... 

Fig. 6. Diagram of a piston reciprocating pump, a = motor, b = drive mechanism, c = plunger piston, d = piston seal, e = column check valve, f = to column,...

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