Testing bigger particles made easy
measurement systems to its portfolio of analysers for in-process
applications, allowing users to measure larger particles of up to
2.5 mm.
The Parsum range of particle probes are specifically designed to measure larger particles and can be inserted directly into the process line, removing the need for sampling.
Real-time measurement, with automatic feedback to a central control room or computer terminal, enables direct upstream process control and monitoring of current production trends, the company claims.
Ideal measuring points are on the exit of granulators or spray driers to measure final grades, or on the feed materials for mills as an indication of 'processability'. In both scenarios, the probes are used principally for process optimisation.
The company produces a range of probes suited to different process environments.
The Parsum IPP 50 is the standard unit for larger particles and all types of granulates, where the process concentration is low and no dilution is needed. The Parsum IPP 50-SE, meanwhile, uses air for more concentrated systems and for materials that are adherent and require dispersion. The IPP 50-Se unit has a low power input which allows its use in hazardous conditions.
The Parsum probe works on a patented fibre optic counting principle. It simultaneously measures particle size and the velocity of individual particles, and can calculate number and size distributions based on statistics coupled with the technique of Spatial Filter Velocimetry, in which particles pass through a laser beam, casting a shadow on a linear array of detectors.
As the particle interrupts the light between transmitter and receiver, the time taken to cut across the laser beam is measured.
A burst signal is generated due to the falling particle and its frequency measured, and it is from this that particle velocity is calculated. In passing through the laser beam the particle generates a secondary 'pulse' signal which indicates the time associated with the falling particle as it blocks a single detector in the array.
Particle diameter is determined using chord length calculated by knowing the time of the pulse signal, velocity of the moving particle and the distance between the spatial filters.
Parsum probes require no calibration, produce volumetric size and linear number distributions, provide constant measurement and do not assume particles to be spherical, making it appropriate for use in a wide range of food industry applications.
