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GAS SUPPLIES AND GAS DISTRIBUTION SYSTEM pressure of 15 bar and a temperature of 15°C the cylinder will contain 6.000 n/l of dissolved Acetylene. To fill the cylinder with this quantity of Acetylene normally takes 8 hours.

normal concentration. Hence it is important that Acetylene is handled only in well ventilated areas. Important safety reminders Under certain conditions Acetylene forms readily explosive compounds with copper, silver and mercury. For this reason contact between Acetylene and these metals, their salts, compounds and highconcentration alloys must be avoided. It is generally accepted that brass containing less than 65% copper in the alloys, and certain nickel alloys, are suitable for use in Acetylene service under normal conditions. Never use makeshift hose connectors made out of pieces of copper pipe - use a proper hose connector.

When you open the top valve to use the Acetylene, the pressure in the cylinder falls and the gas is released from the Acetone. If this process proceeds too quickly, ((boiling)) occurs in the cylinder, rather similar to the effect of opening a bottle of sodawater, and some of the Acetone will emerge with the gas. This is harmful both to the cylinder and to the weld. Admittedly, Acetone burns, but with very different characteristics from Acetylene. The rule is therefore that the cylinder should not be emptied more rapidly than by about one-eighth of the contents per hour. This corresponds to about 750 n/l per hour. However, for a short while (maximum 30 minutes) extraction from a full cylinder at about 15°C may be increased to about 2.500 n/l per hour. After that, the cylinder must be set aside for a period of rest.

Acetylene cylinders must be stored and used in an upright position. If the cylinders are used when lying on their sides or sloping, some of the Acetone will run out and into the reduction valve and hose.

Drawing gas from Acetylene cylinders The Acetylene cylinders are filled with a porous mass, which is saturated with Acetone. An Acetylene cylinder with a volume of 40 litres normally contains 16 litres of Acetone. The Acetylene gas dissolves in (is absorbed by) the Acetone. At a

If gas consumption is greater than a single Acetylene cylinder can deliver, a sufficiently dimensioned gas central installation is normally used. The following gives the extraction rates for various combinations of interconnected A-40 Acetylene cylinders: Maximum extraction, nl/hr

Acetylene Cylinders A-40

Continuous

Intermittent*

1 2 3 4 5

700 1400 2100 2800 3500

2500 5000 7500 10000 12500

5.02

*FuIl cylinders at approx. 15 °C.

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