MIL-HDBK-1005/7A
(2) Will the pump perform satisfactorily in
parallel with others?
b) Curve Shape.
Evaluate the curve shape on the
basis of the following:
(1)
Does the curve need to rise continually to
the shutoff head?
(2) Is there any likelihood that the pump may be
caught in a dip in the curve, resulting in unstable operation?
(3) Motor Overload. Do not allow motor overload
at any possible operating point of the curve. Check the
operating range, shutoff condition (if applicable), and low head
condition.
5.4.2.2
Rotary, Reciprocating, and Jet Pumps. Study the
manufacturers' rating curves, and select accordingly. Provide
relief valves for all positive displacement pumps, between the
pump and the first shutoff valve on the discharge line.
5.4.2.3
Airlift Pumps. Use airlift pumps for low lift service
or when aeration is needed.
5.4.3
Speed.
Selection of speed is governed by the criteria
given below:
5.4.3.1
Centrifugal Pumps .
The governing factors for
centrifugal pumps include:
DESIGN PUMP LIFE (years)
FACTORS
MORE THAN 10
LESS THAN 10
Maintenance costs
Low
High
Maximum speed (rpm)
Operates less than 3 hpd
1,800
3,600
Operates more than 3 hpd
1,200
1,800
5.4.3.2
Rotary Pumps . Operating speeds should not exceed
those approved by the manufacturer.
5.4.3.3
Reciprocating Pumps. Operating speeds should not
exceed basic speeds prescribed in HI Hydraulic Institute
Standards.
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