Replacing valves in pipework 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, time consuming and problematical as to where to drain the liquid.
Once liquids have been brought to a standstill, a specially designed flexible jacket is wrapped around the pipe at each point where the freeze is required.
A nozzle in the jacket is then coupled to a cylinder of liquid carbon dioxide for the Qwik-Freezer and liquid nitrogen for the Accu-Freeze.
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 CO2/ LN2 is injected into the space between the jacket and the pipe, 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.
Georgia Gascoyne, CEO for Huntingdon Fusion Techniques, said: “Qwik-Freezer is the industry standard portable CO2 pipe freezing system, in use around the world, covering pipe diameters from 3/8inch to 8inch (9 – 200 mm).
“The quick and easy to use system requires very little set-up time and is the only CO2 pipe freezing system capable of freezing larger pipe diameters.”
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