Hydraulic Load Cells
Hydraulic load cells are arranged around a piston and cylinder, which measure displacement under force via a diaphragm attached to the piston. This in turn registers pressure change in a tube of filling fluid, either compressing or expanding under load, which is then detected and converted to a readout by the load cell.
Hydraulic pressure load cell types are often preferred in particularly hazardous, environmentally challenging or difficult-to-access zones and application types, due to their relative robustness compared to the more sensitive electrical circuitry of many other load cell types. They’re widely used in simple industrial and agricultural weighing applications, where typical environmental challenges might include moisture, dirt or chemical exposure.
Micro Load Cells
Micro load cells typically rely on semiconductor, rather than foil, strain gauges to sense and measure deformation, due to their especially compact nature. They can be bought in a wide variety of configurations and styles, including both compression and tension types, and used in an almost equally broad range of applications as larger versions (provided they will tolerate sufficient forces).
Micro or miniature load cells are most commonly used for measuring compression forces in zones where space is at a premium. They typically provide extremely accurate and precise readouts ranging anywhere between 10 g to 2000 lbs depending on the make and model.
When looking to buy micro load cell transducers, it should be noted that the vast majority of micro versions are only designed to measure force from a single direction, and so it’s advisable to be especially aware of any ‘parasitic forces’ (i.e. being exerted from another direction) which may affect the accuracy or usefulness of the measurement.