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CORRUGATED PIPE. Pneumatic plugs may be used in corrugated
pipe. However, the plug will not fully ll the pipe corrugations, resulting in
reduced contact area. Maximum allowable back pressure, therefore, must
be reduced by 50% (eg. a plug normally rated for 30 feet of back pressure
must be derated to 15 feet). Minor media leakage may still result along the
longitudinal pipe construction seams. When a plug is used in spiral type
corrugated pipe, a section of corrugations must be lled with a material
such as cement grout to prevent major leakage around the spirals.
PLUGS MAY NOT TOTALLY SEAL SOME TYPES OF PIPE.
When pipes
have rough or very uneven surfaces, such as brick lined pipe, the plug
may allow minor leakage of the restrained media. Some concrete pipe is
very porous and media may leak past the plug through the pipe itself. The
surface of the pipe may need to be coated with sealant to prevent such
leakage. Other concrete pipe has a cast in place plastic liner, and leakage
may occur under the liner. The edges of the plastic liner may require
caulking to provide a leak free seal. Other pipe with sharp (90º) corners,
longitudinal seams or defects may provide a leakage path past the plug.
DO NOT attempt to prevent the leakage described above by over-ination
of the plug. Over-ination will not provide a better seal and the plug may
rupture catastrophically and dislodge at high velocity. Such leakage may
only be minimized or eliminated by mechanically blocking the leakage path
with material such as caulk or cement grout.
OTHER PIPE SHAPES.
Pneumatic plugs may also be used to block pipes
that have non-circular cross sections (eg. elliptical, arch or rectangular).
Measure the pipe and call Cherne toll free at 1-800-843-7584 for
recommendations for your application. A standard plug or fabrication of a
custom sized product may be recommended. Cherne can quickly determine
what plug will best meet your performance requirements.
MEASURE INSIDE PIPE
DIAMETER AND
SELECT THE
PROPER
PLUG
SIZE
PNEUMATIC PLUGS
MAY BE USED
TO BLOCK OTHER
PIPE SHAPES
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