8.
Pressure Equalization Valves
A. A pressure equalization valve is in the aft bulkhead of each cargo compartment. (See figure 1.) The valve uses two flapper type valves to maintain nearly equal pressure between the cargo compartment and the cavities behind them. Each equalization valve is composed of two flapper type valves. One flapper hinges away from the cargo compartment and the other toward the cargo compartment. The valves open at a pressure difference of about 4 inches of water.
9.
Blowout Panels
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A. The forward compartment has a blowout panel in the forward bulkhead and one in the aft bulkhead. The forward compartment bulkhead blowout panels are aluminum alloy sheets and the edges are held in place by rubber mouldings. The forward compartment also has a blowout panel in the ceiling. It is a fiberglass sheet. The edges are held by depressor and cap strips.
B. The aft compartment has a blowout panel in the ceiling. It is a fiberglass sheet. The edges are held by depressor and cap strips.
C. The blowout panels are pushed out of their supports by, and thus relieve, pressure differences which might other wise do harm to the airplane structure or the compartment lining.
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CARGO AND ACCESSORY COMPARTMENTS - CLEANING/PAINTING
1. General
A. This procedure provides a high pressure jet and vacuum pickup method for removing dirt, sludge and grease from the lower cargo compartments.
2. Equipment and Materials
A. Dual Air Vac - Clarke Model TMDGU, Clarke Division Magraw Edison Co., 2800 Estas St., Muskegon, MI 49441
B. Drum - 30 or 55 Gallon capacity, mounted on casters
C. Hose Assembly - 6 foot length, 1 1/2-inch ID; with swivel connection to pump - Graco Model 206-266 siphon tube
D. Hose - 50 foot length, 3/8-inch ID, 2250 psi working pressure with 3/8-inch pipe fittings at each end - Graco Model 207-831
E. Portable Airless Pump - Graco Bulldog Model 207-463; Hydraclean Pressure with 7 gpm output, 1200 psi working pressure, 10:1 ratio pump on Pneumatic Cart Model 208-156, with Regulator Assembly 206-199; Graco Inc., 60-llth Ave NE, Minneapolis, MN 53440
F. Alkaline Solvent Emulsion Cleaner (Ref 20-30-31)
Any of the following:
(1)
Allied-Kelite 28
(2)
Calla 301
(3)
Cee Bee A-410B
(4)
Cee Bee 280
(5)
Dubois C-1102