The Sealfast M. P. Pipe Plug design utilizes a combination of a positive seal with the restraining tension produced by the set screws on the pipe I.D. to withstand total line loads up tp 150 PSI. (consult Factory). Designed to be “self-restrainning” the Sealfast inflatable pipe plugs can withstand higher pressures than competitors with a minimum amount of pipe wall depth.
The Sealfast pipe plugs “double acting “ ring principle , embodies a design which produces “tensile” stress in the outer wall (cross section), of the uninflated ring, while the inner wall (cross section), is under “compressive” stress.
When the ring is inflated, this built-in “stress balance” is “upset”, causing both the inner and outer walls to deflect “outward”, by forming similar reverse curved configurations without stretching the walls, while sharing equally in radial displacement.
Total displacement action and sealing inside the pipe is accomplished with a minimum volume of inflation gas, which conserves valuable time and inflation pressure supply.
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