Learning Objective: Identify components and operating procedures for gaseous oxygen servicing trailers. There are several different models of gaseous oxygen servicing trailers currently in use by naval activities. They are all similar in operation; therefore, only one, the type NO-2, manufactured by Aeroil Products, Incorporated, is described here. The trailer is shown in figure 5-13.

Equipment provided on the trailer includes six manifold control valves with pressure gauges; an upper and lower manifold; two pressure regulators; a recharge valve; four shutoff valves; a drier assembly, six cylinders, and connecting flexible hoses; and a servicing hose fitted with a line servicing valve fitted with a high-pressure charging adapter. The function of each of these components is described in the following text.

COMPONENTS 

Complete familiarity with the following trailer components is a basic prerequisite for safe operation.

MANIFOLD CONTROL VALVES. The six manifold control valves serve to shutoff the flow of oxygen from the cylinders to the system being charged. These valves are lever-type valves. The manifold control valves should not be used for long-time storage. Always use the handwheel type valves located on the cylinders.

UPPER MANIFOLD. The upper manifold provides connections/ mounting for the six manifold control valves with pressure gauges (each connected to a supply cylinder), a recharge valve, and two upper/ inlet shutoff valves that connect to the inlet side of the regulators.

PRESSURE REGULATORS. The pressure regulator controls the charging pressure when the trailer is being used to service aircraft oxygen systems. Only one pressure regulator is used during operation. The spare is provided to ensure uninterrupted operation should one fail.

RECHARGE VALVE. The recharge valve is provided as a means of recharging the trailer cylinders directly through the upper manifold without the necessity of removing the cylinders. When not in use, the valve adapter should be fitted with a dust cap.