Kaman Extreme Environment Sensors - Manual (Page 11)

High Temperature Displacement System
The metal sheathed cables and transducer will withstand a minimum continuous
service temperature of 1000oF (See appendix A for exact numbers which depend on
the sensor). This sheathed cable is designed to withstand a 6.35mm (.25 inch)
minimum bend radius without degradation providing an appropriate mandril is used.
The first bend should be as far from the sensor as practical to avoid bends at the
cable-sensor weld. The cabling is shipped in a coil approximately 30.5 centimeters
(12 inches) in diameter. Bending this cable work hardens the sheath such that
repeated bends are made with increasing rigidity and therefore risk. Thus it is
strongly recommended that the sensor cable be bent a minimum number of times
(preferably only once) during testing and use. Use a mandril to bend the cabling in
less than a 25.4 mm (1.0 inch) radius to avoid buckling. Since the cabling and its
terminations are a vital and costly part of the system, they should be handled with
the same care given the sensor. The sensor is connected to its matching electronics
unit via flexible, interconnecting cable. The identification number on the cable must
also be matched properly to the records. Since the cables, both metal sheathed
inorganic insulated and flexible organic insulated, are a portion of the bridge
network, any modifications to there length will negate the factory calibration. Thus it
is of paramount importance that only the cabling provided by Kaman
Instrumentation is used. Cable length modifications such as shortening the metal
sheathed cable or lengthening the interconnecting cable can be provided at a later
date if desired. This would require recalibration at additional cost by Kaman
Instrumentation.
Operating temperatures of the interconnecting cable and connector are as follows:
Interconnecting Cable: -55oC to 105oC (-67oF to 220oF)
Interconnecting Connector: -75oC to 150oC (-100oF to 300oF)
A metal seal can be used at either flange surface to obtain a gas tight seal if desired.
One possible configuration using a Haskel HS4 series "K" type seal is recommended.
The sealing surfaces of the sensor, mount, and metal seal must be thoroughly
cleaned with a solvent prior to assembly. Furthermore, the flange of the sensor and
mount must be polished and have a finish compatible with the seal. Radial scratches
and abrasions will preclude making a tight seal. The Haskel "K" type seal is
fabricated of silver plated Inconel 750 with a gold flash. Such a finish can probably
be removed if not compatible with the testing environment, however, the absence of
the sealing function attributable to the plating may prevent an adequate seal.
Further information can be found in the Haskel literature from:
Bulletin S-6
Design Handbook
Plated Metal Spring Type Flange Seals
Haskel Engineering and Supply Company
100 East Graham Place
Burbank, California 91502