Spring discs are an elastic mechanical element. When used in bolt joints that are subject to thermal or mechanical shock, they deflect and move with the bolted joint. Hence, they compensate for developed looseness. The reactive power of the spring disc serves to keep the bolt joint tight under all conditions. Principal applications include piping construction, compression joints, steam piping joints, valve and pump connections, and others in the petrochemical field.
A principal cause of flange leakage is abnormally high loads produced by thermal expansion and contraction of a bolted joint. Generally, flanges are under static load conditions. However, in large piping systems, there may also be mechanical shock from compressor related piping. Thermal and mechanical shock differential can cause variation and yielding in bolt loads. To protect against these conditions, always use spring discs under the nut or bolthead.
Pre-stressing or torquing the bolt at factory installation is not sufficient to protect the flange joint under unexpected temperature variations and mechanical shock loads in the field. By absorbing peak stresses, spring discs prevent damage to the bolt, gasket and joint.
Flange Spring Materials
Our flange disc springs (FL Series) and metric flange springs (MFL Series) are manufactured from stainless 17-7 PH (Armco) precipitation hardened steel, with a Rockwell hardness of RC 38-43. Their optimal operating temperature is between -220° C to +300° C.