Plastic-lined valve with easily replaceable parts - having PTFE mating surfaces reached through inspection cover

摘要

The whole internal surface is plastic-lined. The spindle end broadens out to a disc with a tapered edge covered with a PTFE sleeve which is shrunk on. This mates with a PTFE seating ring which press-fits into the shoulder of one limb of the valve. To replace scored mating surfaces, an inspection cover is removed and the seating ring is taken out or the sleeve is cut out with a simple tool. A new ring is pressed into posn. or a cylinder of PTFE is placed in posn. on the spindle disc and shrunk on by hot air or a flame.