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Get Acrobat Reader You will need Acrobat Reader to view pdf Thermalok® Process

Thermalok Pipe Spool Dimensions

Resistoflex Thermalok steel pipe and PTFE liner act as one integral piece. Combining dissimilar materials with very different coefficients of thermal expansion, our precision Thermalok Process locks the isostatically molded PTFE liner into the pipe housing, making it full vacuum rated from -20°F to 450°F. We developed and patented the Thermalok process for lining steel pipe in the 1950's, and have been the world leader in the manufacture of plastic-lined piping products ever since.

The Thermalok process positively locks the plastic liner in the metal pipe housing while effectively relieving stresses that could cause unwanted liner movement in service.

Thermalok Process
  • Incoming lots of resin are analyzed in our Quality Assurance laboratory for conformance to established raw material specifications.
  • The liner is processed under controlled conditions to a size somewhat larger than the I.D. of the steel housing into which it will be installed. It is then thoroughly inspected for conformance to design specifications. Next, the PTFE liner is subjected to a battery of quality tests designed to ensure liner integrity.
  • The liner is then drawn through a sizing die at carefully controlled draw rates which results in a calculated reduction in the outside diameter.
  • A programmed heating cycle relaxes the liner inside the steel housing, resulting in a snug liner fit. Design allowances are incorporated in this procedure to eliminate undesirable stresses in the finished product.
  • Both liner ends of the pipe spool are then hot flared. Temperature, time and pressure are carefully monitored.
  • The finished pipe is then tested in accordance with ASTM F1545 standards.
This unique Thermalok process provides lined pipe with dimensional stability under vacuum, pressure, and thermal cycling conditions, which prevents liner buckling and cracked flares within operational limits.

Thermalok Field Flare Pipe

Resistoflex supplies Thermalok Field Flare pipe with moveable liner for our distributors and end users who fabricate finished pipe spools in their shops. Moveable liner allows the fabricator a wide variety of flange options - rotating, welded, or threaded. Thermalok Field Flare tooling is available - please see our Tooling and Fabrication section for more information. Available liners are PTFE, PVDF, and polypropylene.

The Thermalok Field Flare product is made with the same process as our standard flanged Thermalok pipe spools, but the relaxing step is modified to result in a moveable liner. When fabricated by a distributor or end user with Resistoflex tooling and in accordance with our procedures, the finished piping has identical performance (pressure/temperature/vacuum) as our standard factory-made pipe spools. All field flare piping has been qualified to the rigorous testing requirements of ASTM F1545.

Drawing and Sizing

Thermalok Process



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