by the introduction of nitrogen at 200 psi and then the addition of a proper charge of carbon dioxide.

The addition of nitrogen in carbon dioxide cylinders provides additional pressure. This pressure expels the carbon dioxide at extremely cold temperatures (below 0F) at a much higher rate than would the pressure of the carbon dioxide itself. Winterized cylinders have a carbon dioxide charge less than rated capacity. As a result the total pressure is lower at high temperatures than with rated charge, even though nitrogen has been added. Thus winterized cylinders can be subjected to 160F without the safety disc rupturing.

REPLACING SAFETY DISCS AND WASHERS ON INFLATION VALVES

If you are not familiar with the flotation equipment, replacing safety discs and washers on the various CO2 cylinders can be very difficult. You will need some special tools to replace the . safety disc and washers on inflation valve assemblies A-128/817444, MIL-V-81722 (Flu-6/P), and MIL-V-25492 (figure 3-9). You will require a torque wrench, a five-sixteenth inch socket, and apiece of hex stock 5/16 x 2 inches long. O n c e y o u h a v e t h e s e t o o l s, changing the safety disc will be a simple process.

WARNING

Before you perform any work on inflation valves, ensure that CO2 inflation assemblies are completely discharged. Do not remove the valve or valve safety disc plug from a charged CO2 assembly. Insert the 5/16-x 2-inch stock into the disc plug and remove the safety disc plug. Then insert the safety disc and washer as shown in figure 3-9. To replace these items, simply reinstall them into the inflation valve. Remember to install new washers and safety discs. Use a torque wrench to make the following torque valve adjustments.

Valve Torque (lb)

A-18 29

MIL-V-81722 (Flu-6/P) 15-17

MIL-V-25492 28-35

(Hood valve)

NOTE: While you are tightening the safety disc plug, align the insert with the plug.