Section 7: Pumps and Pumping Systems

Section 8: Piping and Fluid Flow

Section 9: Air and Gas Compressor and Vacuum Systems

Section 10: Materials Handling

Section 11: Heat Transfer and Heat Exchange

Section 12: Refrigeration

SERIES PUMP INSTALLATION ANALYSIS

A new plant addition using special convectors in the heating system requires a system pumping capability of 45 gal/min (2.84 L/s) at a 26-ft (7.9-m) head. The pump characteristic curves for the tentatively selected floor-mounted units are shown in Fig. 1; one operating pump and one standby pump, each 0.75 hp (0.56 kW) are being considered. Can energy be conserved, and how much, with some other pumping arrangement?

Figure 1: Pump characteristic curves for use in series installation.

Calculation Procedure:

1. Plot the characteristic curves for the pumps being considered

Figure 2 shows the characteristic curves for the proposed pumps. Point 1 in Fig. 1 is the proposed operating head and flow rate. An alternative pump choice is shown at Point 2 in Fig. 1. If two of the smaller pumps requiring only 0.25 hp (0.19 kW) each are placed in series, they can generate the required 26-ft (7.9-m) head.

Figure 2: Seriesed-pump characteristic and system-head curves.

2. Analyze the proposed pumps

To analyze properly the proposal, a new set of curves, Fig. 2, is required. For the proposed series pumping application, it is necessary to establish a seriesed pump curve. This is a plot of the head and flow rate (capacity)...