The heart of any Weighbridge is the Load Cell. The load cells are highly accurate transducers, designed to sense force or weight under a wide range of adverse conditions. They’re the most essential part of an electronic weighing system, but also the most vulnerable. The sensing or spring element is designed in such a way it develops a strain, directly proportional to the load applied.
The strain gauges, are usually connected in a multiple of four, called a Wheatstone bridge configuration. This converts the very small change in resistance into a usable electrical signal.
Load cells may be damaged because of (shock) overloading, lightning strikes or heavy surges in current, chemical or moisture ingress, mis-handling (dropping, lifting on cable, etc.),vibration, seismic events or internal component malfunctioning. The load cell needs to be properly sealed against the environment.
Our Hermetically sealed, stainless steel load cells are made from 17-4PH stainless steel – which offers the best performance qualities of any stainless alloy. Hermetically sealed, stainless steel load cells are more expensive than other load cells due to the additional costs of sealing the load cell.
Hermetic sealing will ensure the integrity of your strain gauge section of the cell in corrosive or washdown applications. A true hermetically sealed load cell incorporates a welded header cover over the gauge cavity where the cable is attached. The welded header is the key to preventing moisture penetrating the inner load cell
Watch out for potted loadcells that are only designed for “normal” environmental factors encountered in indoor or protected outdoor weighing applications.
If you choose to use a non-hermetic cell to save some dollars, in a washdown application, and you have to keep changing the loadcell due to failure from moisture, then the cost is much greater than using a hermetically sealed load cell in the first place.