How do I fit liners in Impulse?

James Heal provides the following for this instrument:

  • Cork liners  393 - 527

These comply with the P2117A Specification and are supplied ready to use.

  • Neoprene Liners 758 – 566

These comply with ISO 12945 - 1 and NF G07 - 121.

The liners need to be cleaned and run in before use. Details of this procedure can be found in Annex A of ISO 12945-3. Both types of liner must be conditioned before use. 

  1. Select either the cork or neoprene liner as specified by your chosen test method.
  2. Roll the liner into an overlapping tube and insert into the chamber.
  3. Insert finger between the liner and the test chamber and push the liner inwards to make dent as shown in the diagram below.
  4. Butt the short edges of the liner up to each other.
  5. Apply even pressure around the liner to push the dent back out and to secure the liner flat against the chamber walls.

It is common for the cork liners to rotate as the test is in progress. To prevent this it is acceptable to tape the outside edge of the liner to the chamber wall at the butt joint with a short piece of 25mm wide masking tape.