A Gamma Point Level Switch is used to determine the level in vessels at a particular point. These gauges are ideal for level measurement in Mining and other harsh applications where other techniques do not offer the reliability required.
The point level gauge operates on the principle of gamma ray absorption.
It comprises a gamma emitting source and an appropriate gamma detector, mounted on opposite sides. As the process level rises, the gammas are blocked from the detector, due to the absorption of the gammas in the process material.
The source of gamma rays is an encapsulated isotope (normally 137Cs) which is housed on a lead filled steel container (source holder). The source holder is equipped with a collimated aperture and shutter mechanism to control the beam of gammas being emitted. As an option to the standard metal TAG, a solid state I-TAG is available to record the isotope details and allow non contacting electronic reading thereof.
In certain applications, one source (with appropriate collimation) may serve more than one level detector for multi-point measurement applications.
This non-invasive measurement is unaffected by process pressure, temperature, viscosity, refractive characteristics, etc. and does not suffer wear and corrosion normally associated with invasive measurement systems.
The gamma detectors may be supplied in either of two formats viz. Detector with Remote mounting transmitter electronics or detector with integrated processing electronics. The detector standardly provides a volt free relay output to indicate a change in status.