The Pipestoppers® Division at Huntingdon Fusion Techniques HFT® provides a cost saving solution to carrying out repairs or modifications on pipes with liquid inside. Qwik-Freezer™, the industry standard portable CO2 Pipe Freezing System requires little set-up time and is the only low cost CO2 Pipe Freezing System capable of making ice plugs in pipes up to 8” (200 mm) diameter. Qwik-Freezer™ kit is easy to use. A specially designed jacket is wrapped around the pipe at the point where the freeze is required. A nozzle on the jacket is then coupled to a cylinder of liquid CO2 by means of a high-pressure hose. When the liquid CO2 is injected into the space between the Qwik-Freezer™ jacket and pipe, it immediately expands to form a solid carbon dioxide (dry ice) at a temperature of -78ºC (-109ºF). This low temperature quickly freezes the contents forming a secure “ice plug” which seals the pipe.
The Qwik-Freezer™ ice plug forms only in a section of pipe covered by the jacket so the resulting rise in pressure is very small and there is no damage to the pipe. The Qwik-Freezer pipe freezing kit can be used safely on iron, lead, stainless steel, copper, brass and plastic pipe.
Low-cost accessory obviates power station shutdown
A new compressor installation, to be completed within a short window of time, was going well until a problem was discovered. The design drawings failed to show that a cold water valve extension handle clashed with the air inlet pipe of the compressor. Critically, this was the only isolating valve from the cooling water main header and could not be moved without closing the cooling water system.
This would have also meant shutting down the whole power station, which was not an option. Potential solutions included re-routing the inlet pipework of the compressor and contracting in a specialist pipe freezing company to enable the valve to be moved. All initial potential solutions would have taken time to organise, which could have affected the timely completion of the project.
Freezing was considered to be the best option but this valve was welded into place and freezing would have to be made far enough up stream not to be adversely affected by the applied heat from the grinding and re-welding operations. As the water pipe was 75 mm diameter, it was not possible to acquire one of the commonly available domestic or commercial plumbers’ freezing kits, as these only have a capacity up to 50 mm. As time was of the essence, an Internet search discovered a Pipe Freezing Kit for 3” pipe available from the Pipestoppers® Division of Huntingdon Fusion Techniques HFT®.
The HFT® Technical Team were quickly able to reassure us that Qwik-Freezer™ Pipe Freezing Systems were a proven option for this size of pipe and within 24 hours we had a kit in our possession. Installation was easy and CO2 bottles were obtained from the local BOC gas supplier. The freeze worked well, taking around an hour to freeze the pipe. This freeze allowed time to grind out the welded valve, plus a length of pipe, re-weld a flange back onto the pipe at a new position and install a new valve. The job took around two hours to complete in total and at cost of around 25 per cent of a specialist contractor.