SEALFAST "Double-Acting" Principle

The SEALFAST "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 SEALFAST ring is inflated, this built-in stress balance is upset, causing both the inner and outer walls to deflect "outward." This forms 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 air, which saves considerable physical effort and time.

The SEALFAST "Double Acting" principle embodying thick wall construction of the ring is absolutely essential to withstand the heavy duty service for which the plug is intended, while also improving safety.

The "H" Dimension Concept

The "H" Dimension Concept (see figure 2), is designed into all "LP" Test Plugs and "MP" Test Plugs 18" in size and over. The "H" Dimension Concept permits the "edge-on" entry of the test plug into the pipe I.D. At this point it can be rotated to the closure position and installed.

The "H" dimension allows large diameter "MP" Test Plugs to be "rolled" as a wheel, in the upright posture within the pipe for ease of transportation to the test location in the system.

When the "H" dimension is properly utilized, "MP" Test Plugs will negotiate bends up to 90° angles, provided a reduction in pipe I.D. does not occur.

SEALFAST Design Features