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Live Loading Springs for Pump and Valve Manufacturing

Valve Industry   LNG Tanker   Offshore machinery                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              Green Ball Valve diagram with label "Live Loaded Gland and Seat Springs"
Temperature sensitive applications, such as flow control valve operation in the petro-production environment, require components that are capable of reacting to unpredictable expansion and contraction behaviors. Solon Manufacturing Co. Belleville spring and washer products exceed industry standards to confidently withstand extreme temperatures as well as corrosive environments. Whether you have a custom material specification or unique application challenge, Solon’s full-service design engineering and production teams can help you with your requirements. An American Belleville spring manufacturer established in 1949, Solon Manufacturing Co. supports pump and valve applications such as: 
  • Ball seat valves
  • Butterfly valves
  • Gaskets, sealings, packings
  • Flow control 
  • LNG / FLNG
  • Valve live loading applications
  • High-temperature pipe flanges

Solon® Belleville Springs and Solon® Flange Washers should be used to keep bolted joints tight when the bolted joint integrity is a concern.

Belleville springs maintain load on a seal, gasket or packing in valve actuators and other valve components. They can be easily retrofitted into existing valve designs with minimal revisions.

Live Loading of Packing

The term "live loading" means using a Belleville spring to maintain load on a seal. Many valves utilize studs or bolts to exert load onto the gland follower, which applies stress to the packing. As the valve is operated, the seal material consolidates during each operation. High temperature and thermal cycling can accelerate this loss. As this occurs, preload is lost on the seal. Once the preload falls below a certain threshold, a leak will occur. Since the stretch in the stud is small, loss of preload and packing stress can occur quickly.

Flange & Bonnet Gasket Live Loading

Flanges and bonnets are often sealed with a gasket. The gaskets ability to seal partly depends on the stress maintained on its sealing surface. Flange bolts are tightened to a given preload to generate this sealing stress. Similar to valve packing, this original preload is lost over time due to effects such as differential thermal expansion and thermal cycling. Once a certain amount of preload is lost, a leak can occur. Therefore, Belleville washers are used to increase the elasticity of the fastening system to reduce this preload loss. Solon Flange Washers are often used for bonnet applications.

Live Loading Ball Seats

Ball seats provide a seal between the ball and the valve's body. An entire article can be devoted to seat design as there are many materials and styles to consider. The load on the seat must be within a certain range for the seat to be effective. If the load is too low, there will be leakage. If the load is too high, excessive wear will occur and/or the valve will not operate. Often, the seat will have little elasticity (especially metal seats). Since the valve components are generally machined to a set of tolerances, it is difficult to guarantee the seat is properly loaded. 
 
The ball seat can be live loaded with a Belleville spring to ensure that the load is within the proper range. Since these loads are usually much lower than those used to seal packing stems or gaskets, the spring stresses can be lower.

Actuators or Mechanisms

Some low-stress Belleville springs can be designed to "snap over". This is similar to an "oil-can" effect. Some relief valves are designed with snap-acting Bellevilles' to open the valve quickly at the desired load. 

Learn more about the use of our products in the pump & valve manufacturing industry:

Case Study: Solon® Flange Washers for LNG Applications
Case Study: Solon Flange Washers Solve Gasketed Joint Leaks for Heat Exchangers
Technical White Paper Download: Valve Live Loading Using Solon Belleville Springs
Technical White Paper Download: Why Do Gasketed Joints Leak?
Video: Live Loading with Solon Flange Washers | Reduce Fugitive Emissions

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