Valve Live Loading

All valves leak to some extent, and more than half of industrial fugitive emissions generate from leaks at the valve stem. Leaks often go undetected until the next scheduled maintenance. This is not only dangerous but can result in costly fees and EPA enforcement actions. Preventing fugitive emissions and other issues involves ensuring that all your bolts have enough packing stress.

Live Loading Valves to Reduce Fugitive Emissions

Valve stem seals need stress to be effective. Packing stress fails naturally over time and is typically caused by creep, relaxation, thermal expansion, high cycles, and vibration. Packing stress issues can, however, be minimized.

Valve live loading is an effective measure to reduce the loss of packing stress. This process involves using Belleville spring washers to apply a spring load to the gland follower of a packed valve. The spring load creates packing stress, which helps keep bolted connections tight under normal operating conditions.

Using Belleville Washers for Valve Leak Applications

Belleville springs, also known as disc springs, are washers used for valve live loading applications. These specialty washers are compact and have a conical-disc shape that flattens at a given rate, providing high spring forces and elasticity for a range of valve leak applications. The size of the spring determines the amount of packing stress. Using different washer stacking compositions also provides a way to increase packing stress when required. Different valve live loading applications for spring washers include:
  • Ball seat valves
  • Butterfly valves
  • Gaskets, sealings, packings
  • Flow control
  • LNG / FLNG
  • Actuators or mechanisms
  • Pumps

Learn more about the use of Belleville washers in valve applications:

Technical White Paper: Valve Live Loading
Case Study: Flange Washers Reduce Fugitive Emissions in LNG Applications
Video: Live Loading with Solon Flange Washers | Reduce Fugitive Emissions
 

Ensuring Proper Live Loading for Valves

Belleville springs provide a solution for various valve leak applications by maintaining bolt integrity and preventing loosening. To ensure effectiveness, you must consider several factors when selecting a spring washer.
  • The operating environment, including temperature and exposure to corrosives substances, is a critical selection factor. We offer several materials and finishes to meet your needs.
  • Consider any size constraints such as ID, OD, and the height of your spring stack. Our spring washers are stackable and come in a range of metric and imperial sizes.
  • Bent or pitted valves and improper packing are among other factors that contribute to packing stress loss. Always thoroughly inspect your valves before live loading to ensure there are no other issues contributing to leaks.
  • Always follow manufacturer instructions to ensure proper installation and pre-stressing of your Belleville springs.

Contact Us to Discuss Your Valve Leak Applications

Solon Manufacturing Co. provides a wide variety of highly configurable washer products for live loading and maintaining tight gasket connections. Contact us for more information today.