TM 10-6640-216-13&P
1-13.
FUNCTIONAL DESCRIPTION OF LABORATORY SYSTEMS - continued.
flow in through the purge vents. (Refer to Figure 1-5). These motors are turned
on from power routed from relay K2. Power is also routed to two microswitches
located on the purge ports. As long as the purge port doors are open, power passes
through the microswitches to two control relays located in the distribution box
below the ECUs controls. This power energizes the control relays which in turn,
turn on the evaporator fans on high in each ECU. In the event that a purge vent
door closes, the ECU for that vent will turn off because of loss of power to its
control relay. After the purge cycle is complete, power is removed from the control
relays which turn off the ECUs. Power is also removed from the damper motors in
the air plenums which will return the air dampers to a normal configuration.
(b)
Blower Assembly. The blower assembly is located inside cabinet No. 5 and
is used to ensure that all contaminated air is exhausted from under the cabinet
assemblies. It is provided power from the circuit breaker CB2 and is activated by
placing switch S2 in the ON position when the automatic purge cycle is
completed.
(5)
Vacuum-Air Pressure System. The vacuum-air pressure system is powered by a
120 VAC vacuum-air pressure pump located in cabinet No. 9. The pump receives power
from CB5, through VAC AIR switch (S4), located next to the sink.
b.
Water System. (Refer to Figure 1-6). The water system supplies the laboratory with
fresh water for use with laboratory tests. Water can be supplied from either one of two sources,
From an external source connected to the SUCTION connection in the utilities box, or from the
water reservoir (a 30 gallon tank) located under the counter top, front roadside corner. This
water reservoir can be filled by using the FILL connection and gating valve with pressurized
water, or the WATER RESERVOIR till pour spout (located front roadside corner exterior) by
pouring water into fill spout, Two gating valves are used to line up the correct input to the
water pump.
(1)
Pressurized/Supply Lines. Pressure throughout the water system is maintained
by a pressure switch and the water pump. (Refer to paragraph 1-13. a.(3).) The output of
the water pump is passed through a check valve which maintains water on the output
side of the water pump. From the check valve water is routed to the various units
requiring water. The RVP bath and water demineralize have valves and fittings to
connect tubing, The faucet, eyewash, and ice maker have no valves to isolate the water
system from them.
A surge tank is mounted in parallel with the supply lines to
maintain even water pressure and flow. Air pressure is added to the surge tank prior to
operation to maintain header pressure in the system,
(2)
Drain Lines. Drain lines in the water system are supplied for the sink, RVP bath,
distillation testing unit, refrigerator, and the copper strip corrosion bath (which has its
own shutoff valve). These drains are referred to as the SINK DRAIN outlet in the
utilities box. The water reservoir has its own drain in the utilities box labeled TANK
DRAIN,
c.
Vacuum-Air Pressure System. (Refer to Figure 1-7.) The vacuum-air pressure system
provides vacuum and air pressures needed to perform various laboratory tests. The vacuum
and air pressure are supplied by a 120 VAC vacuum-air pressure pump mounted in cabinet No.
9. (Refer to paragraph 1-13. a.(5).)
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