COAX TCC® system

 

COAX range, Dockweiler – Double-wall tube for hazardous or temperature-controlled fluids in industrial environments

 

Cost-effective configuration of the COAX system, suited to applications where ultra-high purity is not required but secondary containment remains critical.

 

The COAX TCC system is designed for fluids where a leak is not an option, without requiring microelectronics-grade purity: toxic process gases, explosive or corrosive fluids, viscous media that must be kept at temperature.

 

Two concentric tubes, an inner process tube in TCC quality and an outer safety tube also in TCC, separated by a controlled annular space.
Used in biopharmaceuticals for viscous products (PEG, suspensions, polymers, crystallisable active ingredients), in fine chemicals, in process gas distribution and in energy/industrial applications under regulatory containment.

 

Surface finish

 

Component	Treatment	Internal Ra	External Ra
Inner process tube	TCC, bright finished, chemically pickled	≤ 0.8 µm (20 µin)	—
Outer safety tube	TCC, bright finished

 

Cleaning and inspection according to ASTM A632 S3 and ASTM G93 Level D. Degreased for gas service in accordance with CGA G-4.1-2018.

 

Material

 

 

316L stainless steel, controlled sulphur for orbital weldability.

 

Compliant with DIN 11866 series C.

 

Operating principle

 

Three operating modes for the annular space, selected according to use.

 

• Leak detection using a carrier gas, typically nitrogen at an overpressure of 0.5 to 2 bar, with a downstream differential pressure sensor. Any pressure loss or detection of the process medium in the annulus triggers the alarm and allows the section to be isolated before any release.

 

 

 

• Passive secondary containment, where the annulus collects any leak and routes it to a secure drain point, with no release to the atmosphere and no contamination of the room.

 

 

 

• Temperature maintenance, where the annulus carries a heat-transfer fluid, glycol water or low-pressure steam, to prevent a viscous product from solidifying in the inner tube. Resins, certain polymers and active ingredients crystallise rapidly below 40 °C: the temperature-controlled outer tube ensures continuous flow.

 

 

Connection and welding

 

 

System prepared for orbital welding on the inner tube.

 

 

Dimensional standards

 

 

Metric and imperial dimensions compliant with ASME BPE, SEMI F19 and DIN 11866 series C.

 

 

Traceability and packaging

 

 

Each component is supplied with a 3.1 material certificate according to EN 10204, with dual traceability for inner and outer tubes (grade, heat, batch, dimensions).

 

Laser marking on the OD of the outer tube.

 

Full traceability from raw material to delivery.

Components packed in individual polyethylene sleeves, with capped ends.