Our Gamma-Dense® range of NDG Density Gauges work on the principle of gamma ray absorption.
The source of the gamma rays and the detector are bolted to opposite sides of the process pipe. The amount of gammas reaching the detector is (inversely) proportional to the mass of the material between the source and the detector. Since the volume within the pipe (measured volume) is fixed, this measurement can be calibrated to produce mass per unit volume or “Density”. This measurement requires linearising and other conditioning, which is performed by the density transmitter.
The source of gamma rays (Usually 137Cs) is encapsulated and housed in a steel container filled with lead (source holder). The source holder is equipped with a collimated aperture and shutter mechanism for controlling the beam of gammas emitted.
Electronic Tag (i-Tag)
An electronic tag (i-Tag) is available as an option to permit electronic (Contactless) reading of the source data. This non-contact measurement technique enables simple installation and requires very little maintenance.
Being non-invasive, measurement is not affected by pressure, temperature, viscosity, refractive characteristics etc. and does not suffer from wear and corrosion from the process. This results in reduced maintenance and improved reliability of the measurement. Indication of the measurement is available in many formats such as: (SGU, % Solids, Brix etc.). Accuracy is typically 0.5% of the measurement span.