Proper installation, usage, and maintenance can prevent early failures and extend element life.
Proper Handling:
Bayonet elements are very fragile due to the ceramics throughout the elements, and the insulating materials at the terminal end. Extreme care should be taken when handling bayonets. Avoid contamination of the element material with any type of oils or chemicals which may cause early failure due to reaction between contaminant and element material. Be sure all terminal connections are tight and terminal lugs are locked on tightly with double nuts to prevent overheating at the connections.
Radiant Tube Preparation & Usage:
It is recommended that the bayonet elements be removed from the radiant tubes at least yearly to clean the inside of the tubes. The elements at the terminal end should be allowed to breathe some air as oxidation of the heating elements is the best prevention to early failure due to contamination.
Element Replacement Strategy:
Element resistivity changes over the life of a heating element. The combination of old & new elements in a phase will likely cause failure due to resistance mismatch. To prevent resistance mismatch, elements should be replaced in groups of “series phases”. For example, if an element fails, and it is in series with one or more other elements in the same phase, all elements in the same phase should be replaced at the same time. Any remaining functional elements can be saved to be used with other old elements in the same phase.
Horizontal Bayonets:
Where possible, horizontal Bayonets are designed to prevent failure by including fewer paths for electrical shorting at the bottom of the element. Potential failures could be a result of oxidation build up in the radiant tube. Therefore, it is important to ensure bayonets are installed with the proper side down.