Extract of Basics of industrial valves –Tightness systems– 3/8

One of the fundamental constraints of individual valves is tightness.
For every kind of valve, two main types of tightness must be considered :

thightness system on industrial valve manufacturer guichon

1. Process/Atmosphere thightness

Extract of the Basics of industrial valves – material used in our training program.

1.2 Gland/Stuffing box

Each valve equipped with a stem or a piston can be fitted with a gland, which ensures the tightness between the process and the atmosphere.  The gland, or stuffing box, consists of a stack of compressed rings (called packing) composed of one or several different materials.
The packing profiles may vary.  The selection of materials used in the gland will take into account the process temperature and the chemical compatibility of the fluid.

The nature of the packing might also depend on the type of application.  For example, they could be FDA approved for food applications, or PMUC certified for a nuclear application.
One qualified design against fugitive emissions (type: TA-Luft-ISO 15848) can consist of double gland packing with a leak detector, tightened down by self-compensating spring washers, guaranteeing a leak rate of less than 1.10-3 torr.l/sec.
 

tightness systems on industrial valve manufacturer guichon