Page 14 - publication

Introduction
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GRUVLOK® – THE ENGINEERED COUPLING
HOUSING (A) FLEXIBLE OR RIGID
The Gruvlok Coupling housing is designed to self-center
around the pipe. The housing encircles and retains the gasket
against the application of internal system pressure or vacuum.
The housing key sections ft into and engage the pipe-end
grooves around the entire pipe circumference, thus restraining
the pipe ends from separation due to the application of
internal pressure.
Flexible Couplings provide designed-in clearances between the
housing key sections and the pipe grooves to permit both
angular and longitudinal movement of the pipe. Rigid
couplings grip the pipe and lock the joint into position.
All housings are coated with paint for general service
applications. The paint serves to provide protection against
normal atmospheric corrosion. However, for couplings used in
corrosive environments, hot-dip galvanizing, and stainless steel
are available.
GASKET (B)
The unique single piece “C” style design of the gasket has been
engineered to provide a pressure responsive, leak-tight seal in
both pressure and vacuum applications without the aid of
external forces. The “lips” of the gasket are molded so that
upon installation onto the pipe ends they provide compression
against the pipe surface to establish the leak-tight seal.
The gasket cavity functions as a “pressure reservoir”. Pressure
within the pipe system is applied to the internal surfaces of the
gasket which increases the sealing force and enhances the
leak-tight seal. In vacuum systems, non-pressure-responsive
seals tend to “lift off” the pipe, producing leak paths. However,
the Gruvlok gasket reacts to the negative pressure (higher
outside atmospheric pressure) as to improve the sealing
capability of the gasket.
Gasket
Reaction
to Pressure
Gasket
Reaction
to Vacuum
BOLTS AND NUTS (C)
Heat treated oval neck track head bolts serve to connect and
secure the housing segments together. The oval neck design
prevents turning of the bolt while tightening the hex nut with
a single wrench. The bolt size and corresponding wrench (or
socket) size for the hex nuts are shown in the chart below.
A
B
D
C
GROOVED PIPE ENDS (D)
The ends of the pipe must
have a groove in them which
may be either cut grooved
or roll grooved. The grooved
pipe ends engage the
coupling keys, thus, providing
a self-restraining, mechanical
joint capable of resisting
the separation of the pipe
ends due to the application
of system pressure. The
groove diameters must be
dimensionally accurate to
obtain the maximum beneft
of the Gruvlok Coupling.
GL-2.10