The Pipestoppers® Division of Huntingdon Fusion Techniques HFT®'s Accu-Freeze™ Liquid Nitrogen (LN2) Pipe Freezing System is a controlled system to freeze stationary liquids in a selected section of pipe or tubing.
The system can accurately and safely form an in-line ice plug, capable of withstanding 138 bar (2,000 Psi) in pipes up to 12" (305 mm) diameter allowing repairs or modifications to be made without shutting off or draining the entire system. The ice plug does not expand outside of this point, meaning there is no damage to the pipe.
The procedure starts with wrapping copper tubing and a specially designed insulated jacket around the section of pipe to be frozen. The liquid inside the pipe must be brought to a static condition.
Each jacket accommodates pipe sizes from 6" (150 mm) to 12" (305 mm). The design of each jacket incorporates adjustable straps, allowing the user to alter the jacket size according to the application requirements.
The Accu-Freeze™ wrap is placed around the pipe up stream from the section to be repaired. Next, the recommended surface temperature of the pipe is set by the digital controller, which can be done from a remote location.
Accu-Freeze™ takes over by automatically injecting the LN2 through the system to form an ice plug. Once the plug is formed, maintenance or repair work can be carried out without shutting down or draining the entire system, saving valuable time.
Each unit can be set to 220 V or 100 V and a working scale of ºC or ºF.
The Accu-Freeze™ System is desired when pipes carrying liquids other than water are in need of repair or maintenance. For example, pipes carrying milk, beer and liquids containing refrigerants. For pipes carrying water, please see our Qwik-Freezer™ System.
The technique can be used safely on pipes made of the following materials:
- Plastic (however this will take up to three times longer)
Safety precautions must be taken at all times when using the Accu-Freeze™ System, including protective clothing and sufficient ventilation.