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Pipe Freezing
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  • Pipe Freezing Service
What Is Pipe Freezing?
  • Freeze the contents of pipe line to form a solid plug, then the downstream pipeline could be separated from the pipe pressure system, repair job could be carried out.

  • P1>P2 means Solid Plug can withstanddifferential pressure, then the downstream pipe line could be isolated from the system.
Application of Pipe Freezing Service
  • Pressure system maintenance: repair or replace valve
  • Pressure test after pipeline modified
  • Fire system maintenance
Application Conditions of Pipe Freezing Service
  • Pipe materials:Freeze various material pipes except PVC pipe, iron pipe and lining pipe. Except for austenitic stainless steel and copper nickel alloy pipes, other pipes are with low temperature brittleness, so defect area should be avoided, and knock or other force are prohibited.
  • Diameter:O8mm-O1000mm.
  • Kinds of contents: pipe must be filled with liquid. Normal liquid is water.
  • Temperature: the bigger diameter of pipe, the lower temperature of contents. See figure below, water data of diameter to temperature.

      Note:above data is tested in lab., it is just for reference.
  • Content flow: Generally no flow in the pipe. Sometimes small pipe or slow enough flow is possible.
  • Ratio of diameter-time-liquid nitrogen
      Note:above data is tested in lab., it is just for reference. 
  • Freezing method: liquid nitrogen, dry ice and compressor.
  • Pressure: less than 15Mpa for water pipe and 5Mpa oil pipe.
  • Repair length: distance between plug and heat-repair point: 0.5m for stainless steel, 1m for carbon steel, 2m for copper or aluminum alloy, 6m for copper pipe. If cannot meet the min. distance, other measures will be taken to isolate the heat.