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Oxygen Servicing Unit

Product Specification Table
Gas Oxygen 99.99% Pure
Pressure 0 – 3600 psi / 0 – 250 bar
Flow Rate Gaseous HP 70 scfm / 2000 Litres/Min
Flow Rate LOX 10 US Gallons/min / 38 Litres/Min
Hoses 1 x 50ft / 15 metre
Tank Coding DOT 4–L
Tank Capacity 75 Gallons / 300 Litres
Length 124 ins / 315 cms
Width 60 ins / 152 cms
Height 54 ins / 137 cms
Weight 3100 lbs / 1400 Kg
Temperature of gas Within 7°C of ambient

Detail of the Oxygen Servicing Unit

Aircraft Oxygen Servicing Unit

McNaughton Dynamics Limited has developed a new universal “Oxygen Servicing Unit” to supply all Oxygen requirements, both liquid (LOX) and HP and LP gaseous (GOX).

This innovative design provides large amounts of Oxygen gas from a liquid Oxygen tank, for charging aircraft LOX pots and Oxygen cylinders of all capacities. It is based on the successful Zwick range of Cryogenic Servicing Units, in service with air forces worldwide for the last twenty–five years.

Designed to be very simple to operate, the self-pressuring “Oxygen Servicing Unit” (or OSU) fills LOX pots and aircraft cylinders safely and quickly from one source of liquid.

The machine is filled with 300 Litres of Liquid Oxygen which is stored in a 400psi / 27 bar cryogenic tank. Some of the liquid is boiled off and used to pressurise the tank so as to provide a continuous supply of pressure. A patented internal pump provides high pressure Oxygen upon demand. After the tank and pump, the liquid is vaporised into gas by aluminium heat exchangers, warmed to ambient temperature and delivered to the control panel for distribution to the aircraft through hoses and control valves. The LOX is delivered to an aircraft LOX pot mounted on the side of the OSU. The hose is terminated with a “ground half coupling” for easy and safe transfer of the LOX.

As many air forces of the world have supplies of liquid Oxygen for pilot breathing, it makes sense to develop an “all in one” Oxygen Servicing Unit. This unit can fill LOX pots both on and off the aircraft. With its internal pump that is always available for use, the OSU can also deliver large quantities of high pressure gaseous Oxygen for cylinder charging, again both on and off the aircraft.

Features and Benefits


The OSU saves time, by charging aircraft systems quicker and eliminating the requirement to handle cylinders. The unit is filled either once a week or up to once every three weeks depending on usage. This is done by a Liquid Nitrogen delivery vehicle and takes about 15 minutes. There is no pressure raising time as the Oxygen is always available.


The OSU takes up much less space than the 20 cylinders it replaces and can be stored outside in all weather. It occupies 52 square feet or 4.8 sq metres only and can easily be moved manually or with a towing vehicle.


The cost of gas generated from liquid is less than cylinder gas. There are no costs associated with storing, transporting or changing heavy (80 Kg) gas cylinders and no empty cylinders have to be returned.


The OSU is designed with high reliability components. The machine is based on a tried and tested military unit of which over a thousand were produced for service all over the globe. The hose end components are more robust for flight line service.


The OSU is designed to handle and dispense both liquid and gaseous Oxygen safely. The tank is designed to DOT 4–L standards and can be operated for life without the need for annual testing.