Valve - Optimum

Live loading of Valve packing glands with Belleville Washers

"Live loading" means using Belleville washers to maintain load on a seal.

Most of the valves utilize studs or bolts to exert load onto the gland follower, which loads the packing.

While Valve stem is rotated or moving back and forth under the fluence of temperature and pressure in the piping, some of the packing material is lost during each operation.

As this occurs, preload is lost on the gland follower. Once the preload falls below a certain threshold, a leak will occur.

Adding Belleville washers on the gland follower under the gland stud nuts to compensate the pressure decrease and fasten the studs Which ensures the proper seal pressure on the packing and avoids leakage through packing.

Live loading with Belleville washers or disc springs are widely used in butterfly valve, Sampling valves, ball valves, pigging valves, rotary plug valve and etc.

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Material Available:

●Carbon Steel:

51CrV4 (1.8159 / 6150)

●SUS300 Series Stainless Steel:

SUS301 (1.4310)

SUS304 (1.4301)

SUS316 (1.4401)

●Precipitation Hardening Stainless Steel:

17-7PH Stainless Steel (1.4568)

●Thermally Stable Stainless Steel:

X22CrMoV12 1 (1.4923)

●High Temperature Stainless Steel:

Inconel 718 (2.4668)

Inconel 750 (2.4669)

Nimonic 90 (2.4969)

Belleville Springs loaded on Valve Seats

In Heavy-Duty Valve Seat Structure, disc spring is installed in the valve seat retainer. The continuous elastic force of the disc spring presses the valve seat ring against the ball surface, creating a stable seal.

Belleville Springs on Trunnion Ball Valve Seats

Unlike the floating ball valve, the ball of a trunnion ball valve is fixed.

Trunnion ball valves are used in high pressure applications and in large sized valves.

The ball remains centered on the shaft within the downstream Belleville seat spring and the upstream Belleville seat spring.

As the pressure builds downstream, a Belleville spring is used on the downstream seat, creating a seal.

The Belleville spring on the upstream seat also flexes with the pressure movement of the seat and maintains the upstream seal.

Under extremely high temperatures and pressures, such as in nuclear applications, the use of Belleville springs compensates for the differential thermal expansion of the internal parts at elevated temperatures by absorbing the heat expansion.

They provide the initial sealing force in applications relating to gradual building pressures.

Therefore, Belleville springs on ball valves ensure that the valve will not get stuck and can open and close with ease under these abrasive conditions.