Double Gland Packing for Globe Valves

The client obviously has an issue with containment of the process fluid, and has issued the criterion as a standard for his maintenance staff, among others, to follow. So you should too, Boss!

This is a optional against the bellow seal valve. some of our application in CL2 service we use double gland packing valve.

Regards;

Balbhadrasinh

Yes, it is for added safety.

The main gland is (mostly) bellow type and auxiliary gland is of packed type as shown in the figure:

If the main gland, bellow in this case, leaks, the auxiliary/secondary gland takes care until a replacement is made.

I agree with previous colleagues on the service type. This is the reason to require a double packing: your client tries to prevent any fluid leakage outside the valve pressure boundary, and the most frequent leakage way is through stem (packing).

There are several ways to improve the "through stem leakage".

One is to use the so called "zero leakage" valves. That means there is a metal bellow (as shown on a previous answer) or diaphragm (like Kerotest type valves) which seals the possible leakage way unless the bellow or diaphragm breaks.

Another is to use a double packing separated by a lantern ring with a "leak off" connection between both packing sections in order to detect the leakage of the lower part before the complete packing leaks.

To improve the packing time dependent behaviour and keep a more constant load above it, from several years ago it's not uncommon to specify "live loaded" glands, in which a pre-compressed Belleville spring keep the force of the gland bolting over the gland flange.

Kind regards

With double packing it will cut down on packing leaks. This will also give your packing a longer life before change out of packing. I know that all the Baumann globe valves have what they call a duel pack, this is a packing follower that works as a double packing setup.