CHAPTER 12 COMPRESSED AIR SYSTEM
Section I. General
12-1 General. Compressed air system provides air to nine air stations Six of these (stations 1, 2, 4, 5, and 7 in ROWPU
space, station 3 in workshop) are for operating air-powered Impact tools and general cleaning blowdown. The seventh
outlet (station 6) provides air for propelling a PIG (an 8-inch long polyfoam cylinder) through the shore discharge hose to
force out water in the hose before reeling in the hose. Stations 8 and 9 provide regulated compressed air for blowdown of
two seachests to remove foreign material that may be clogging seachest intakes.
12-2 Description. This system provides compressed air to five air stations in the ROWPU space, one in the workshop,
and one on stern weatherdeck. It also provides compressed air to two air stations for blowdown of seachests in void 2
starboard and void 4 port. These outlets, with other major components, valves, and piping are shown schematically in
Figure 12-11 for Barge 1 and In Figure 12-2 for Barges 2 and 3 and are listed in Table 12-1 Equipment specifications,
maintenance information, and manufacturer's service manuals are contained in TM 55-1930-209-14 & P-7.
12-3 Capabilities. This system provides compressed air up to 155 psi for seven air stations and 40 psi for two air
stations for seachests blowdown.
12-4 Special limitations. Use of air station 6 and its associated 25-foot air hose is restricted to providing compressed air
for forcing water out of the shore discharge hose prior to reeling In this hose.
Section II. Description of operation
12-5 Activation. When compressor starts, air is drawn through intake filter, manifold, and suction discs into compressor
cylinders. This air is compressed, then discharged through delivery discs to temperature reducer where heat is partially
removed. From temperature reducer, compressed air Is discharged through a check valve into receiver, increasing air
pressure in receiver. When system is set on automatic (normal setting), compressor is controlled by an automatic air
regulator switch (pressure switch). When air pressure in receiver reaches factory set upper limit, compressor will unload
and turn itself off. When air In receiver reaches factory set lower limit on pressure switch, compressor will be activated
and pump air into receiver. When system is set on manual and START button Is pushed, compressor pumps air into
receiver until STOP button is pushed.
12-6 Air flow. Opening air compressor main air supply valve directs compressed air from receiver through air filter 1 for
removal of moisture and particles. This air then flows to the air stations in the ROWPU space and workshop. Quick
disconnect couplings at these air stations permit connection of a 50-foot air hose so pneumatic tools may be used Air also
goes through air filter 2 before reaching air station 6 This filter traps oil and grease and prevents contamination of drinking
water shore discharge hose when compressed air pushes PIG through hose prior to hose retrieval. Compressed air
pressure regulators 1 and 2 further reduce air pressure to a manually set level, normally 40 psi, for blowdown of
seachests in void 2 starboard and void 4 port.