General air needs

Pneumatic splicers are operated by compressed air. Therefore the air supply must be appropriate. The following points are important:

  • Splicers generally operate at a pressure between 3 and 8 bar. Pressure will be chosen according to application, but it must be as uniform as possible.
  • The air supply should be reasonably dry and clean, with the lowest possible flow resistance.

Because the time taken to make a splice is short, transient pressure drops associated with other demands in the mill may become important. When the splicer is operated, line pressure at the splicer head normally drops by about 1 bar. If there are restrictions in the line, air will not be replenished, so that the pressure drop will be greater; weak splices may result. Compressed air installations should therefore be designed to minimise pressure drop. Never use narrow-bore supply tube; this introduces resistance.

When there is doubt about the quality of the air supply system, a pressure gauge should be fitted - temporarily - as near as possible to the splicer, so that static pressure and pressure drop can be monitored. This is particularly desirable in an installation which uses long lengths of coiled hose;  losses in such hoses tend to be significant, and may adversely affect splicing performance.

Sometimes, static line pressure is known to be adequate, but there are demonstrable problems with transient pressure fluctuations. Then it may be useful to fit a few metres of wide-bore pipe or other form of plenum, close to the splicer. This will act as a reservoir, to minimise pressure drops while the splicer is in use.

Do not fit lubricators in the line very near to the splicer; an excess of oil on the yarn may weaken the splice.

What are the rules of design for the air-line supply to a splicer?
What should be the quality of the air supply; should it be dry and filtered?
Can splicers be fitted with portable air bottles instead of air lines?
Are special high pressure air supplies needed to splice extra-tough yarns such as aramids?