Design Improvements of WIKA’s AWS
- Issue: Clamping bolts loosen in vibration and thermal cycling applications.
SOLUTION: WIKA’s body construction welds together the upper and lower half of the diaphragm body. The clean welding design supports vibration and thermal cycling applications. Space requirements for the assembly are reduced by eliminating the traditional hardware of bolted seals.
- Issue: O-Ring and/or gaskets are not always compatible with the process being used.
SOLUTION: The diaphragm is recessed and welded to the lower body of the AWS using a TIG weld technique. Eliminating O-Ring and gaskets eliminates process compatibility issues. It also enhances the instrument’s upper temperature limits while maintaining material compatibility between the lower body and the diaphragm.
- Issue: The thread contact between the gauge and seal changes in demanding temperature and vibration applications as well as during the installation and orientation of the instrument.
SOLUTION: The seal upper housing, which is designed to mate with the threads of the process gauge, is welded. This enables the thread contact to be fully resistant to thermal cycling, vibration and incorrect installation. The back weld ensures that integrity is always maintained between the instrument and the seal, and eliminates the potential loss of system fill fluid through the threads, a particularly critical issue with this NPT connection. Because the gauge cannot be unthreaded from the diaphragm seal, the assembly qualifies as a dual containment system.
Additionally, WIKA’s AWS assembly is fully traceable. Order and material information is engraved on the gauge, allowing additional MTRs to be ordered.
The WIKA Model 23X.34 process gauge is easily convertible to liquid fill (making it resistant to resonant frequencies and vibration damage). Its pressure gauge housing is a safety case with blowout back. The movement has a built-in 30% over-range protection with no loss of accuracy. The 23X.34 design includes a mechanical over and under stop safety mechanism and the thermoplastic case is rated for continuous use to 300º F. The gauge’s accuracy is rated at 0.5% FS. The standard available bourdon tube and socket materials are Monel® and 316SS.
WIKA’s AWS has been designed to meet the safety demand requirements of the process industry. Every weld point is helium leaked checked after each operation. Additionally, the AWS is fully tamper resistant and capable of extending gauge life by a factor of 2.5 or more. The AWS design is well suited for high vibration and thermal cycling applications and, when configured correctly, is suitable for pump discharge applications.