How are gas hoses manufactured?
|By law, high pressure gas hoses have to be manufactured with at least two layers, and most have three. Hoses for use with small low pressure appliances only require a minimum of one layer.|
|In the factory, rubber (or synthetic rubber) is warmed and softened on heated rollers before being fed into an extruder. This is a machine that forces the rubber through a long tube-shaped mould.
The resulting tube is then fed into another machine which covers it in a layer of fabric for reinforcement. Plastic, stainless steel mesh and synthetic textiles are among the materials that can be used.
|After that the hose is covered in an outer layer of rubber, synthetic rubber or PVC. The next machine prints the current date, manufacturer’s name, type (high or low pressure) and British Standard number on the side of the hose. It uses a special ultraviolet curing ink which won’t cause any chemical reaction in the rubber.
The ink is then set fast under ultraviolet light, which stops it leaching into the hose.
|Next, the hose is washed in a metal bath under powerful water jets to remove any dirt, debris or ink particles.|
|A machine cuts the hose into lengths, then the pieces are placed on mandrels. These are curved rods which are used to shape the rubber.
The mandrels are put into an autoclave, which is a cylindrical chamber that injects hot steam at high pressure. This starts a chemical reaction which ‘cures’ the hose and makes it more elastic.
|Finally the treated hoses are taken out of the steam chamber and washed again. They are trimmed to remove any rough edges and packed ready to be sent out to customers.|