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Tube Products International March 2013
products & developments
Seals for valves
Gesellschaft für Dichtungstechnik mbH
(GFD) manufactures products for the
valve industry, such as special seals for
valves used onshore and offshore.
GFD seals are used in ball valves,
butterfly valves, actuators, and control
or gate valves. For these applications,
the company can produce sizes from 2
to 3,000mm diameter in various designs.
When
operating
conditions
require
a special solution,
GFD seals come into
operation, for example
low temperatures from
-196°C or -270°C which
can occur in liquid
helium, or in particularly
high temperatures up
to +980°C.
For
aggressive
media, hot gases and
pressures of several
hundred bar, GFD has
developed appropriate
seal solutions.
The company’s spring-energised seals
are made from high quality PTFE
compounds, with an internal stainless
steel spring providing at the sealing lip
permanent elasticity and balances as
cold flow and abrasive wear.
The GFD seals are used in the housing
or in the disc of butterfly valves. The
spring-energised PTFE-seals can be
used at pressure up to 2,500 bar, at
temperatures from -250°C to +316°C
with slow, ‘stick-slip-free’ movement,
and at high speed. They also offer
universal chemical resistance as well
as defined low friction and sealing
force. GFD seals are also designed
for applications other than valves: for
laser systems, seals for aerospace
industry, for gas turbines, autoclaves in
biotechnology and chemical industry,
medical and laboratory equipment,
and sterilisable designs for the
pharmaceutical and food industries.
Gesellschaft für
Dichtungstechnik mbH
– Germany
Spring-energised
PTFE-seals
Metal sealing rings
Polymers and pests
Polymers and plastics are widely
used and form the base of a host of
materials. As large as their use is,
even larger is the threat they face
from rodents and pests. Rodents
are attracted by the sweet smell of
polymers and consequently rodent
damage is one of the most widespread
complaints from the pipe industry.
Gas pipelines, drip irrigation pipelines,
and tubing for wires and cables are
some of the most-affected by pests.
Damage to gas pipelines can have
adverse consequences.
Damage to drip irrigation pipelines by
rodents and subterranean termites
not only defeats the purpose of water
conservation but it is also expensive to
replace the pipe. Damage to the tubing
and wiring harness of automobiles
by rodents can cause thousands of
dollars in losses.
Conventional methods of rodent
and termite control fall short, as
they do not effectively control the
pests. Also, being toxic they cannot
safely be used in all applications. It
is imperative to effectively solve the
problem of polymer piping damage
by pests and also to provide a long-
term solution. With this aim, and
keeping in mind environmental as well
as safety aspects, Rodrepel
®
™ and
Termirepel
®
™ were developed by C
Tech Corporation.
Rodrepel and Termirepel are patented
non-toxic, non-hazardous and
environmentally friendly aversives
specially developed as a master
batch for use in polymeric and coating
applications. The products are RoHS-
and REACH-compliant, and FIFRA
exempted.
They deter the pests by making use
of the sensory mechanisms. They
do not interfere with the properties
of the polymer and are completely
inert within the polymer matrix, apart
from acting as an aversive. Rodrepel
and Termirepel do not volatilise and
are compatible with all kinds of
polymers.
They have undergone extensive
testing at testing institutes like the
BAM Institute in Germany and the
Haffkine Institute in India.
C Tech Corporation
– India
