10
Pressure Drop
Pressure drop simply means that for gas to flow through the hose, for a given pressure at the beginning of the hose (eg.
at the regulator), the pressure at the other end of the hose (eg. at the blowpipe) will be less. For a given flow and length
of hose, the pressure drop in a small bore hose, will be greater than in a larger bore hose. This means, that wherever
possible, hose lengths should be kept to a minimum and hose bore diameters kept to a maximum. Doing so will reduce
the amount of pressure drop, therefore minimising the chance of affecting the performance or stability of the process
flame. Minimising hose lengths also provides greater protection to the hose against damage. Excessive pressure drops
can starve a tip or nozzle of an adequate gas supply, which in turn can lead to reduced flame intensity, backfiring or
flashbacks.
Hose Fittings
The design of the hose connection must provide high mechanical strength and resistance to leakage under a wide range
of conditions. Further, non-interchangeability of hose fittings is maintained by using a right hand (RH) thread for Oxygen
and a left hand (LH) thread for fuel. CIGWELD’s COMET hose fittings fulfil all of these important requirements.
Dimensions for hose fitting connector nuts and nipples are given in AS 4267.
1.09 Electrical System
Ensure that the supply voltage does not vary more than ±10% of the rated voltage, as this may cause a breakdown.
Ensure the power cable machine connection is fully screw on and tight.
Stop operation and turn off the power in the following cases, and have a qualified electrician to repair the machine.
- Broken or abraded cable.
- When the machine has been in contact with water, or in case of liquid damage to machine.
- Abnormal machine operation despite operating the machine according to this operating manual.
- Poor performance or machine breakdown.
