Azbil HLS Series User Manual

11-2
11-2. Structure
The main packing (No. P4519) is PTFE yarn with a carbon fiber core. It features low friction
and can be used for various types of fluids. The main packing (No. P6617CL) is an expanded
graphite packing. The part of it that slides is aligned with an expanded graphite sheet that
was specially modified and lubricated. The adapter packing (No. P6720) is made by braiding
expanded graphite yarn reinforced with PTFE fiber, and features low friction.
These gland packings are tightened by the live-loaded packing system, which is composed of
Belleville springs and other parts. With other systems, in the course of valve operation, seal
performance deteriorates due to loosening of the gland packing. The force of the Belleville
springs reduces the release of tension to maintain the seal. The load on the Belleville springs
can be observed from the position of the packing flange and packing follower.
11-3. Starting Operation
Before operating the valve, tighten (or retighten) the gland. For instructions, refer to 11-4-2,
“(3) Tightening”.
If leakage from the gland continues even after proper tightening, obtain and prepare parts as
indicated in “11-4-1. Preparation for assembly”, and follow the procedure given in “11-4-2.
Assembly”.

Azbil HLS Series Specifications

General

Brand	Azbil
Model	HLS Series
Category	Control Unit
Language	English