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Flex Tubes - DH400 Flex Tube Information

Fluke Calibration DH400 Flex Tubes are constructed of a polyamide core tube with a high tensile, reinforced synthetic fiber and polyamide outer cover. These flexible tubes are used in systems where high pressure flexible connections are needed to facilitate frequent make-and-break operations, allow individual movement of components under pressure, and/or withstand high frequency vibration. Due to their small inside diameter they are generally not suitable for low pressure and vacuum applications where larger diameter tubing is preferred.

These flexible lightweight tubes weigh only 0.5 ounces per yard of length (16 g/m). They can handle working pressure up to 6000 psi (41 MPa), with a flexible bending radius of 0.9 inches (2.4 cm) at maximum operating pressure. Burst pressure of 20000 psi (138 MPa) provides a 3.3 margin with operating pressure.

Inert to ozone and ultraviolet and compatible with an extremely wide range of liquid and gas media, and negligible humidity absorption these tubes are suitable for use in a wide variety of conditions and environments. No de-rating of operating pressure for temperatures from -30 °F to 140 °F (-34 °C to 60 °C).

The inner and outer polyamide layers are Nylon 11. The middle layer is braided Kevlar(R).

The internal volume is about 0.06 cubic inch per linear foot (3 cc per linear meter). Minimum inside diameter of the tubing is 0.08 inch (2 mm)  and maximum outside diameter is 0.2 inch (5 mm).


Tubes are offered with either Swagelok nuts and ferules, 37° flare tip, or as a "plain tip" connection.  The plain tip option is for those who want to apply their own nuts and ferules after installation.  This can be convenient if the tube must be routed through a small passage which does not allow for the larger size of a nut.


The tubes with the pressure fittings go through a testing procedure of pressurizing them to 7,200 PSI for an extended period to ensure no issues with the crimping process and then monitor the pressure to ensure meets leak spec.   This option is not available for the plain tip connection as as such there is a higher risk that a leak may not be detected by our manufacturing team.


The tubes are not guaranteed to be leak free and are not recommended for applications where this is a critical parameter.


Flex Tube life varies by application and may be reduced without a continuing maintenance program. For more details see the Technical Information section of the Parker Polyflex high-pressure hose catalog number 4900 or catalogue 4460-UK (available by internet search). In the catalog search for 2020N-012V30.


Fluke Calibration Flex Tube product information and part numbers are here, Flex Tube Web Page

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