Twin-head reciprocating pump

The use of twin-head reciprocating pump (/. e., having the two heads operated 180° out of phase) functions in such a manner that while one head is pumping, the other is refilling as could be seen in Figure 30.3. 

Figure 30.3 Working of A Twin-Head Reciprocating Pump.

In Figure 30.3, the flow rate of a twin-head reciprocal pump has been plotted against time. The stage-A depicts the drive while the refill zone is vacant while the stage-B evidently shows the two-heads functioning simultaneously thereby the drive and the refill both zones could be visualized. 

Fig. 2. A typical twin-headed reciprocating pump. Reproduced from W.J. Lough I.W. Wainer, High Performance Liquid Chromatography, 1996, first published by Blackie Academic Professional.

In the single-headed reciprocating pump shown in the figure, the mobile phase is being delivered to the column for only half of the pumping cycle. During the drive stroke of the piston, the flow rate is not constant (because the speed of the piston changes with time). The output of the pump is shown in Fig. 2.2e (z). Use of a twin-headed pump with the two heads operated 180° out of phase... 

LKB manufacture a reciprocating twin-pump system with pump heads made of KEL-F. Gradients are formed by a low volume mixer which is located on the low pressure side of the pump, thereby... 

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