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EXPRESSIONS
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Head loss, surge pressure

Friction losses

Volume inefficiency

Velocity jump shock

Nomogram Frequency vs. Pipe ID

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Allow for "overlap" of one displacement to the next. This is dependent on the volumetric efficiency, due to compressibility of your system liquid.
This may radically effect the level of flow fluctuation and pressure pulsation.

volumetric efficiency, due to compressibility

Inefficiency
If in this example, the pump was a triplex then the flow would come to a complete halt between strokes. This is because a rotary driven reciprocating pump sucks & discharges for 180° of rotation and the next displacement begins after 120°. The overlap on triplex at 100% efficiency is therefore 60°. At 77.512% the calculation shows that the 60° has been lost, hence with no overlap the flow will come to a halt between displacements. It will be as "pulsatious" as a duplex.

By the same calculation as the example, if the efficiency was 85% then the lost angle would become 48°. With a "Quin" a new displacement should begin every 72 degrees (360/5), and as discussed above a triplex should displace every 120°. 120° minus 72°=48°. But at 85% efficiency, 48 has been lost, so a Quin can cause as much flow fluctuation as a perfect Triplex if the quin has low volumetric efficiency.


Therefore, A three headed diaphragm metering pump may produce flow fluctuations as bad as, or worse than, a duplex pump or double acting simplex pump. A quintuplex, or 5 plunger pump, may produce flow fluctuations as good as, or worse than, a good triplex pump, it all depends on volumetric efficiency. Consequently, where N2 is a divisor, you would have to treat a triplex N2 as 2x2=4, not 3x3=9.

 

1. Input Data VE – actual displacement divided by 100% volumetric displacement L – Connection rod length R – Crankshaft radius 2. Calculations VI – Volumetric inefficiency X – stroke before valve opening Parameter for calculation purposes Root
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Pulsation Dampeners at Fluid Flow Control

Fluid Flow Control
HEAD 1 HEAD 3 HEAD 2 HEAD 1 DAMPER CHARACTERISTICS CONTROL CHOICE FLOW VELOCITY AND PRESSURE GO TO ZERO BETWEEN EVERY STROKE DEGREES ROTATION PRESSURE HEAD 1 HEAD 2 HEAD 1 PRESSURE ACTIVITY OF A 97% EFFICIENT DUPLEX PUMP FLOW VELOCITY AND PRESSURE GO TO ZERO BETWEEN EVERY STROKE DEGREES ROTATION PRESSURE This is "velocity jump" shock Here is a 77% efficient triplex pump pumping compressible liquid This case needs a Quintuplex pump PULSATION ACTIVITY (DEPENDS ON VOLUMETRIC EFFICIENCY)