MIL-HDBK-1164
6.4.3
Operating Instructions for Ejector (Jet) Pumps. Jet pumps are a type of
centrifugal pump. Because of their relatively low efficiency, they are rarely used for
public water systems. However, jet pumps are inexpensive and require little
maintenance and may be used on wells supplying very small, low-demand systems.
The operating principle of these pumps is described in par. 2.1.4.
Note: All operating rules and troubleshooting checks that apply to
centrifugal pumps apply to ejector pumps.
Start the pump and adjust the manual back pressure valve until the
correct operating cycle is achieved. Do not change the adjustment after the pump is
operating. If pump discharge decreases, check troubleshooting guides for centrifugal
pumps. Also inspect the ejector nozzle and throat for deposits, and check nozzle
submergence.
6.4.4
Operating Instructions for Progressive Cavity Pumps. Progressive or
helical-rotor pumps are positive displacement pumps and not subject to the same
problems as centrifugal pumps. Operate according to the manufacturer's instructions.
Caution: Do not run dry.
Common operating problems encountered with progressive cavity pumps
and possible causes are given in Table 13.
6.4.5
Operating Instructions for Rotary- and Reciprocating-Displacement
Pumps. A general description of positive displacement pumps is provided in par. 2.1.4.
6.4.5.1
Prestart. Rotary- and reciprocating-displacement pumps do not usually
require priming. However, when priming is necessary, follow priming procedures for
centrifugal pumps.
6.4.5.2
Starting and Operating. Always start and operate rotary- and
reciprocating-displacement pumps with both suction and discharge valves open to
prevent motor overload and pump damage.
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