MIL-HDBK 1028/6A
The above information is necessary to determine the allowable
system pressure drops. The minimum pressure required in the receivers for
this example is 65 psig (448.1 kPa) which equals 45 psig (310.23 kPa)
service point pressure plus 20 psig pipeline pressure drop. The maximum
receiver pressure is 240 psig (1,654.56 kPa) since 10 psig is lost in the
piping system between the compressor discharge and the receiver inlet.
3.1.4.2
Selecting ECS Air Equipment.
Table 4 is a summary of the method
for selecting ECS air equipment.
a) An example of an ECS air system is provided in Table 5, based
upon the following conditions:
(1)
Compressor discharge pressure = 110 psig (758.34 kPa)
(2) Pressure drop, compressor to service point = 10 psig
(68.94 kPa) at minimum load and not exceeding 65 psig (448.11 kPa) at
maximum load.
b) A summary of the method for selecting preconditioned air
equipment is provided in Table 6. An example for a preconditioned air
system is provided in Table 7, based upon the following conditions:
(1) Ambient air at 100 degrees F (38 degrees C) dry bulb,
110 grains/lb moisture
(2)
System pressure drop = 0.5 psig (3.447 kPa)
(3) Temperature gain, service point to aircraft =
2 degrees F (16.6 degrees C) dry bulb
(4) Supply fan of 44 brake horsepower, 90 percent efficient,
124,500 Btuh (36,478.5 W) heat gain each.
3.2
Starting Air System. The starting air systems shall comply with
the requirements of NAVFAC DM-3.05. A compressor and auxiliary equipment
shall be provided as a coordinated assembly by the air compressor
manufacturer requiring a maximum of 30 bhp per 100 cfm (2.8 cu. m/min) of
intake air. Compressors shall operate satisfactorily, individually, or in
parallel with any combination of other units. A compressor and compressed
air system controls shall be provided to provide fully automatic operation.
3.2.1
Air Compressor and Auxiliaries. Air compressors and the
auxiliary assembly shall be provided as defined in pars. 3.2.1.1. through
3.2.1.11.
3.2.1.1
Compressor. Two-stage, vertical or horizontal, cross-head type,
single or double-acting, water-cooled, oil-free style shall be provided.
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