What is valve stem packing and its role in industrial valves?

Valve stem packing is a critical sealing component installed around the valve stem inside the bonnet area. Its primary function is to prevent internal media (gas or liquid) from leaking to the external environment while still allowing smooth linear or rotary movement of the stem.

In industrial applications such as oil & gas, petrochemical, and power generation, packing acts as a dynamic seal that must withstand continuous friction, pressure fluctuations, and thermal cycling. Unlike static seals, packing is constantly in contact with a moving component, making material selection and compression design extremely important.

High-performance packing systems are often designed to meet low-emission requirements such as API 622 and ISO 15848-1, ensuring fugitive emissions remain within strict environmental limits.