Disruption free pipe repairs with freezing technology
Companies facing system downtime can drastically reduce pipe and valve repair and maintenance costs with Accu-Freeze available from the Pipestoppers Division of Huntingdon Fusion Techniques HFT.
Luke Keane, technical support at HFT, said: “We carried out an installation of an Accu-Freeze System for a client who was contracted to repair pipework in large blocks of apartments.
“Working in the plant room, access was pretty tight as the pipes were only 6 to 8 inches from the ground. At one end of the pipe there was a pressure gauge and at the other, a 1,000 litre hot water cylinder. Ambient temperature in the pipe was approximately 38ºC.
“We used a copper coil on the 2 inch carbon steel pipe and had to wrap it about 10 inches along the pipe length, wound tight. We then performed a freeze using the Accu-Freeze System connected to a dewar of liquid nitrogen (LN2). Within 50 minutes a solid ice plug had been formed, blocking the flow from the cylinder to enable the pipe section to be cut out and replaced. Following the repair work, the ice plug defrosted naturally and the flow continued in the system.”
Accu-Freeze works by reducing the pipe fluid to a temperature below its freezing point and developing a freeze plug.
This controlled method of pipe freezing uses liquid nitrogen (LN2) to freeze stationary liquids in a section of pipe or tubing. The nitrogen is passed through a coil surrounding the pipe producing a frozen plug inside and hence preventing flow through the part to be removed.
The ice plug only forms beneath the Accu-Freeze™ coil wrap, jacket or aluminium clam jacket.