Sartorius has introduced the PMD700 series of online refractometers for the process analysis and control of liquid- and paste-like process streams in food and pharmaceutical applications.
According to the company, when it comes to determining the concentration, identity or purity of substances, refractometry is the most suitable method.
This is where online process analysers are useful, as they supplement laboratory analysis.
Process analysers deliver results within fractions of a second, meaning that processes can be monitored in real time and controlled automatically.
The PMD700 series offers an accuracy of 0.02 brix or 0.2g/litre (such as sugar solutions) and is suitable for the precise monitoring and control of concentration in process streams.
This includes the monitoring and control of the dissolution of substances, the reduction of solutions, the dilution of concentrates and the determination of dry mass.
The online analyser can be used for monitoring and controlling crystallisation, checking and controlling the correct mixture of various compounds and determining the sugar concentration in different matrices.
The PMD700 is also used, for instance, to monitor concentrations in evaporation procedures, such as before spray drying in the production of instant coffee and tea or to determine the segments between liquids in filling applications, such as filling juices in tanks.
Calibration with the existing reference method results in consistent traceability within the scope of the monitoring and control of inspection, measuring and test equipment.
The PMD700 series is offered in a range of models with a variety of measurement ranges and resolutions.
Sartorius claims that the sapphire or YAG prism with high hardness ensures the ruggedness of the PMD700 in any process.
This enables it to stand up to cleaning-in-place methods.
Thanks to its stainless steel housing featuring IP65 protection, the process analyser can be thoroughly cleaned at any time in a process environment.
The PMD700 compact process analysers operate according to the principle of total reflection.
Light is refracted at the interface between the optical prism and the process solution.
A CCD sensor measures at high resolution the angle at which total reflection occurs and uses installed refractometer scales to calculate the concentration.
The beam entering the solution is not affected by absorption or scattering.
As a result, the concentration can be determined in coloured or dark solutions just as easily as for particles in process streams.
A special feature is the prism-embedded temperature sensor (PES), which is in the direct vicinity of the process stream and the measurement point.
This enables the best possible temperature compensation to be attained.
The process refractometers of the PMD700 series make process steps transparent and minimise fluctuations in product quality.