Welding World Magazine Dec/Jan 2017-2018_V8lo

8
NEWS
DOUBLE FREEZING TECHNIQUE
for large diameter Valve replacement
Replacing valves in a pipeline can
be a challenge, especially when
the pipelines have liquids
running through them. One
option is to completely drain
the system to make the
repairs, which can prove
costly with respect to loss of
expensive fluid, heating or
cooling costs, security matters, time
that system is down plus labour costs.
Pipe Freezing Experts Huntingdon Fusion
Techniques HFT ® recently introduced the
Qwik-Freezer Systems to their
Pipestoppers ® Division. These systems
create ice plugs or freeze seals in the pipes,
avoiding the requirement to drain systems.
Qwik-Freezer is the industry standard
portable CO 2 Pipe Freezing System, in use
around the World, covering pipe diameters
from 3/8” – 8” (9 – 200 mm).
The quick and easy to use system
requires very little set-up time and is the
only CO 2 Pipe Freezing System capable of
freezing larger pipe diameters.
Georgia Gascoyne, CEO for Huntingdon
Fusion Techniques HFT ® said: “Qwik-
Freezer has become the preferred
solution for a wide range of water-carrying
pipework, where valves need to be
changed, in industry sectors such as
petrochemical, building and maintenance
services, food and beverage, hospitals,
water treatment, shipping and aerospace.”
Once liquids have been brought to a
standstill, a specially designed flexible
jacket is wrapped around the pipe at the
point where the freeze is required.
A nozzle in the jacket is then coupled to a
cylinder of liquid carbon dioxide by means
of a high-pressure hose. For valve
replacement, a second jacket is installed on
the other side, creating a double freeze,
blocking flow on both sides of the valve.
When the CO 2 is injected into the space
between the jacket and the pipe, at a
temperature of -78 o C, the pipe contents
freeze and a secure ‘ice plug’ is formed,
which seals the pipe. The ‘ice plug’ forms
only in the section of the pipe covered by
the jacket, so the resulting rise in pressure
is very small and there is no damage to the
pipe itself. The technique can be used
safely on iron, steel, lead, stainless steel,
copper, brass and
plastic pipe.
WELDING WORLD MAGAZINE | ISSUE 06 | DECEMBER 2017