- What construction material are the following cylinders made from
(a) AS 1777 Aluminium
(b) HOAL4 Aluminium
(c) DOT 3AA Steel
(d) 3AL Aluminium
- If the test pressure of a cylinder was known, how would you work out the fill pressure
Fill pressure equals 3/5 of the test pressure
yearly
- Describe the difference between a J valve and a K valve
J valve has a reserve mechanism that will withhold 50 bar of air until a mechanical lever is pulled.
K valve is a simple on/off tap.
- Regulator first stages are commonly described as being balanced or unbalanced. Describe the difference between the two.
Balanced regulators operate independently of the cylinder pressure, i.e. opening and closing forces are independent cylinder pressure
- List three advantages of a balanced 1st stage regulator
(a) Bigger orifices, so allow for higher air flow
(b) Constant line pressure independent of cylinder pressure or depth
(c) Balanced valves can cope with higher cylinder pressures
Also acceptable: Less maintenance, as cylinder pressure doesn’t act directly on seats.
- List four safety systems fitted to submersible pressure gauges.
(a) Pressure relief plug
(b) Pressure restrictor in HP hose swivel
(c) Pressure restrictor in HP port of 1st stage regulator
(d) Pressure relief holes in HP hose
