Accu-Freeze™ Automatic Controlled Liquid Nitrogen Pipe Freezing Systems

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Freeze it and make your Pipe Repair Easy!

Accu-Freeze™, the controlled liquid nitrogen (LN2) pipe freezing system is a method to freeze stationary liquids in a selected section of a pipe or tubing. It is the World's only patented, digitally controlled pipe freezing system thus allowing you to accurately and safety create an ice plug.

By controlling the surface temperature of the pipe, Accu-Freeze™ can safely and accurately form an in-line ice plug, capable of withstanding 138 bar (2000 Psi) in pipes up to 12" (300 mm diameter). 

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The Major Advantages of Accu-Freeze™

HFT Pipestoppers Accu Freeze Pipe Freezing Systems Plugs StoppersThe Accu-Freeze™ temporary plug isolates the section of pipe or tube, allowing repairs or modifications to be made without shutting off or draining the entire system.  

The major advantages of an Accu-Freeze™ System are:

  • Saves valuable time normally lost draining and refilling a system.
  • Avoids complete shutdown of systems and equipment.
  • Prevents waste of large amounts of water.
  • Eliminates handling of contaminated water.
  • Is safe and cost effective.
  • Can be controlled from a remote location.
  • LN2 delivery system is notably colder than other refrigerants. 
  • Standard products to suit pipe and tube sizes up to 12" (300 mm).
  • Capability of automatically controlling the freeze temperature.
  • Has a LN2 delivery, which is more cost effective than other refrigeration systems. 


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Accu-Freeze™ Key Features

HFT Pipestoppers Accu Freeze Pipe Freezing Systems Plugs StoppersThe ice plug only forms beneath the Accu-Freeze™ coil wrap, jacket or aluminium clam jacket which is used on a 6 - 12" (150 to 300 mm) pipe or tube and does not expand outside of the range of jacket or coil.

An ice plug is formed by wrapping copper tubing or specially designed insulated jacket around the section of pipe to be frozen. The LN2 is then injected through the patented control system. 

The water or other liquid in the pipe or tube needs to be in a static condition (no flow). The Accu-Freeze™ wrap is placed around the pipe up stream from the section to be repaired.

Accu-Freeze™ takes over by automatically injecting the LN2 to a temperature set by the user through the system over the in-line ice plug. Once the plug is formed, maintenance and repair can take place without draining or shutting off the entire system.

Each unit can be set to 220 V or 110 V and a working scale of oC or oF.

Optional aluminium jackets are available. 


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Freeze Pipes up to 12" (300 mm)

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The Accu-Freeze™ System is available with a coil wrap, jacket or aluminium clam jacket, which is used on a 6 to 12" (150 to 300 mm).

The design of the jacket incorporates adjustable straps, which will allow the user to alter the jacket size according to the application requirements. 

The controlled freeze process safely creates the ice plug without affecting the integrity of the pipe. (Pipe bursts happen when the ice forms in an uncontrolled manner and creates hydrostatic pressure between ice plugs or against a closure in the line). Detailed user instructions are provided to help the end user select an appropriate location to safely freeze the line. 

In the nuclear industry there are also restrictions regarding exposure of certain pipes to cryogenic temperatures. Accu-Freeze™ makes it possible to create an ice plug while keeping the pipe wall temperature within the allowable temperature limits.

Cryogenic Freeze Seal Jackets (Clam-Shell type) are now available in addition to the standard Accu-Freeze kits.

These Accu-Jackets are popular with customers that need to do repeated freezes on the same size or sizes of pipe. The amount of set-up time is greatly reduced with Freeze Seal Jackets that are manufactured to fit specific pipe sizes and are just bolted around the outside of the pipe.

accu-freeze, qwik-freezer, pipe freezing, tube freezing, liquid nitrogen pipe freezingThe Accu-Jackets have integral injection ports, which connect to the LN2 feed and exhaust ports to vent the gas to atmosphere. They are constructed of high-grade aluminum with a double-wall design that creates an insulating air gap between the liquid nitrogen and the ambient air outside the jackets.

Precision CNC Machined Aluminum Freeze Seal Accu Jackets

  • Doubled walled for superior performance and added insulation.
  • Easy to adapt NPT fittings.
  • Rugged and long lasting for countless freezes.

Accu-Freeze™ Accu Jackets AF1099 Adaptor Kit now available

  • Introducing the new AF1099 Adaptor Kit.
  • Adapts our 2 inch Accu-Jacket to fit 0.5 inch, 0.75 inch, 1 inch and 1.5 inch pipe sizes.

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Frequently Asked Questions

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1.0. What applications is Accu-Freeze™ designed for?
Accu-Freeze™ utilises liquid nitrogen to create the cryogenic temperature necessary to form ice plugs. Freeze sealing is most often used to isolate a section of a piping system where no other ready means of isolation (such as valving) is available. Freeze sealing refers to the process of applying an external refrigerant to a point in a process in order to cause the formation of a solid internal plug from the frozen process fluid contained in the pipe.

2.0. What size pipes is Accu-Freeze™ suitable for?
The Accu-Freeze® insulating jacket accommodates pipe sizes from 6 - 12" (150 - 305 mm). 

Copper coil is used for the smaller sizes.

Aluminium clam shells are available for 2” - 16” (50 mm - 400 mm).

3.0. Is ventilation required?
LN2 is heavier than air and will displace oxygen. Sufficient ventiliation is required, especially when operating in confined areas. 

4.0. What protective clothing should be worn when operating the Accu-Freeze™ System?
Protective clothing i.e. gloves, goggles etc. must be worn at all times when operating the Accu-Freeze™ System. 

5.0. Can I freeze on a weld?
It is not ideal to freeze on a weld unless the weld has been x-rayed.

6.0 Can I freeze contents that are moving within a pipe?
No, the liquid contents of the pipe have to be stationery and non-vibrating

7. 0 Can I freeze liquids other than water?
Yes, milk, beer are all examples of other liquids that can be frozen. Some liquids containing refrigerants can be frozen too, just check with our Technical Team on the type and % content.

8. 0 Can I do a freeze either side of the repair joint?
Yes, this is called a double freeze and necessary accessories can be purchased along with the Accu-Freeze™ kit. A double freeze is required when a valve needs replacing for example.

9.0 What kind of pipes can Accu-Freeze™ be used on?
Accu-Freeze™ can be used on iron, lead, steel and copper pipes. It is also applicable to plastic pipes, but these will take up to three times longer.

10. What about bursting or fracturing pipes?
Pipe fractures are not caused by the ice plug or the freezing process. They are caused by a failure to allow enough space between the ice plug and closed connections. This is due to the increase in pressure that is caused by water that is displaced by the ice plug as it grows that can create a ‘hydraulic ram’ if enough space is not allowed.

11. What if there is a small amount of glycol or other fluid in the line?
It is important to know how much is in the mix and what the freeze point of the liquid is. Note: the ‘freeze point’ may just be a slush and not to the solid state that is required for a plug.

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Shipping Information, Weights and Dimensions

HFT Pipestoppers Accu Freeze Pipe Freezing Systems Plugs Stoppers

Customs Tariff:

European Customs Tariff: 9032 10 80
International Customs Tariff: 9032 10 8090
United States Customs Tariff: 9032 10 8990
Canada Customs Tariff: 9032 10 8990

Product Codes and Sizes:

HFT Pipestoppers® Accu-Freeze™ Pipe Freezing Systems are supplied as a complete  controlled liquid Nitrogen system.

Note CO2 is not included.  

Please see the the tables below for the contents of the full system as well as the Cryogenic Freeze Seal Jackets and all the accessories.

Delivery on the all items is 7 to 10 days.  


HFT Pipestoppers® Accu-Freeze™ Pipe Freezing Systems 


Accu-Freeze™ Liquid Nitrogen Pipe Freezing System up to 12" containing:

1 off AF7000 Carrying Case
1 off AF2000 HV Control Solenoid Valve Header Complete
1 off AF3000 Digital Controller Complete
1 off AF4010 10ft. Flexible Cryogenic Hose
1 off AF4400 Ferrules, Fittings, Tee Connector Asst'd Pack
10 off AF5001 Type "T" Connector Plugs (Male)
10 off AF5002 Type "T" Connector Jack (Female)
3 off AF5004 T/C Wire @ 4ft. with Male End Connector
3 off AF5033 T/C Wire @ 33ft. with Male & Female Connector
1 off AF5100 Thermo Couple Wire 100 ft Roll
1 off AF5101 T/C Wire Spools
1 off AF8000 2 Channel Temp Monitor Battery Operated
1 off AF7100 Operating Manual
1 off F7200 Insulated Gloves
1 off AF7300 Safety Glass
1 off AF9000 6" to 12" Insulating Jacket

AF2000-HV Control Solenoid Valve Header Complete High Flow


Solenoid Valve Only


Manual Isolation Valves
AF3000 Digital Controller Complete
AF4010 10ft. Flexible Cryogenic Hose
AF4020 20ft. Flexible Cryogenic Hose
AF4025 25ft. Flexible Cryogenic Hose
AF4030 30ft. Flexible Cryogenic Hose
AF4400 Ferrules, Fittings, Tee Connectors Asst'd Pack
AF5001 Type "T" Connector Plug (Male) 10 pack
AF5002 Type "T" Connector Jack (Female) 10 pack
AF5004 T/C Wire @ 4ft. with Male End Connector
AF5033 T/C Wire @ 33ft. with Male & Female Connector
AF5100 Thermo Couple Wire 100ft. Roll
AF7000 Carrying Case
AF7050 50 Litre LN Dewar w/ PB Liquid Discharge (22 psi OP)
AF7100 Operating Manual
AF7200 Insulated Gloves
AF7300 Safety Glasses
AF8000 2 Channel Temp Monitor Battery Operated
AF9000 6 to 12" (150 to 300 mm) Insulating Jacket

Accu-freeze™ crypgenic freeze seal jackets

50 mm
75 mm
100 mm
150 mm
200 mm
250 mm
300 mm



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Items available as 'Downloads'

HFT Pipestoppers Accu Freeze Pipe Freezing Systems Plugs Stoppers

Leaflets and general sales material are available to everyone visiting our website.

Restricted access items are shown at the end of this Download section.


HFT Pipestoppers® Accu-Freeze™ Systems A4 Leaflet

HFT Pipestoppers® Accu-Freeze™ Systems Flyer

HFT Pipestoppers® Accu-Freeze™ Clam Shell Flyer

HFT Pipestoppers® Accu-Freeze™ Systems FAQ

Special Note:
The items below are restricted and only available in our Secure Login section.  This is mainly for the protection of our Exclusive Distributor network.  

Should you wish to receive an item mentioned below which is not active as a 'download' link on this page, please contact us or your nearest distributor.

HFT Pipestoppers® Accu-Freeze™ User Instructions Technical Manual
HFT Pipestoppers® Accu-Freeze™ User List Customer Reference
HFT Pipestoppers® Accu-Freeze™ User List  Material Safety Data Sheet MSDS
HFT Pipestoppers® Accu-Freeze™ Price List


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