By Kari Williamson
CIP (clean in place) and SIP (sterilise in place) applications can subject meters to drastic temperature fluctuations in short periods of time, which can lead to a variety of failures in meters. Electrode seals can fail due to differing expansion rates of the liner and electrodes and inferior liner materials can crack and fail causing leakage and loss of measurement.
Yokogawa’s 99.9% pure Al2O3 ceramic liner material increases the host meter’s resistance to thermal shock considerably.
Another advantage of the Admag ceramic design is the electrode construction, which utilises a platinum-alumina cermet electrode. The electrode is a mixture of platinum and alumina powders sintered into the liner during the manufacturing process, resulting in an electrode that is an integral part of the ceramic liner.
This method of construction has several advantages over solid electrode designs: The primary benefit is the elimination of two potential leak paths and, since the electrodes are an integral part of the liner, there is no seal to fail as with meters using solid electrodes. the company says.
A further advantage is that the electrode and the liner have the same thermal expansion rates. Differing expansion rates can lead to improper sealing around the electrode and, over time, can contribute to stress cracks at the electrode/liner seal. Both can lead to premature failure of the meter due to leakage.
