Sway struts are used to restrain movement of piping in one direction while providing for movement due to thermal expansion or contraction in another direction. These sway struts are made of ASTM A387 GR22 weighing at 1,485 lbs each. They are 6″ in diameter and 8’2″ long and are used for main steam valve supports with specifically designed spacers, pins, and retainers capable of restraining movement up to 90,000 lbs at high temperatures exceeding 750F. The turnaround time for this was 6 weeks.
Roller stands are used to support pipelines that expand and contract longitudinally in the axial direction and where vertical adjustment is not necessary. These roller stands are made of stainless steel and designed for a 26″ pipe. They weigh 160 lbs and are capable of supporting 7,500 lbs. Load testing at 1,000F was completed for performance assurance.
Constant support hangers are used to support pipes subjected to vertical movement. The (Fig. PTP 200) constants are designed to support loads from 4,000 lbs to 57,000 lbs. Each weighs approximately 1,500 lbs to 2500 lbs and has a travel of up to 4″ with an adjustable travel stop. Their sizes range from 15 to 100.
The advantage of an adjustable travel stop is that the constant is able to “lock in” at any position within the range of travel for a given constant. This alleviates the need for a total “shut down” of the piping system for temporary conditions such as hydrotesting, repair, or replacement.