Product category:
Humidity and moisture sensing systems
News Release from: Michell Instruments | Subject: Michell Optidew
Edited by the Processingtalk Editorial
Team on 09 November 2006
Precise humidity measurement for coating
processes
Coating processes are widely used in the pharmaceutical and confectionary industries for tablets, pills and sweets: Michell provides the essential humidity measurements needed during coating
Coating processes are widely used in the pharmaceutical and confectionary industries for tablets, pills and sweets The Michell Instruments Cooled Mirror range of instruments utilises a fundamental humidity measurement technique, making their products the ideal solution for the accurate measurement of humidity in process control applications
This article was originally published on Processingtalk on 15 Mar 2004 at 8.00am (UK)
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Most tablets consist of a product core and a coated cover.
The coating can be a variety of proprietary compounds or various forms of sugar.
Coating of the product core is used for several reasons including, preventing discoloration of the core, to counteract an unpleasant or bitter taste and to prevent the core from degrading when exposed to the ambient atmosphere.
Further reading
Dew point transmitter is IS for CNG applications
The new Easidew TX transmitter is a small and reliable intrinsically safe dew point transmitter, recently developed by Michell for CNG applications
DryCheck dew point instrument is easy to install
The DryCheck self-contained dew point instrument is an accurate, stable and economic instrument with a simple sampling system, that is above all else easy to install
Increased accuracy in cooled mirror instruments
Michell Instruments has developed a new technology to increase the accuracy and reliability of their Optidew Cooled Mirror Hygrometer instruments, the Frost Assurance System Technology (FAST)
There are two aspects to tablet coating.
The generation of inlet air of a known humidity and the monitoring of the drying process itself.
In order to ensure a high quality product is maintained it is important that the humidity of the air fed to the drier is validated.
The fundamental Cooled Mirror principle, in products like the Michell Optidew, provide the control signal for the generation of an inlet air with known humidity.
This is passed over the product during the spray coating process to guarantee that the tablets, or sweets have a consistent, smooth, high finish outer coating.
The monitoring of the drying process avoids excessive or under drying of the product.
Excessive drying will incur additional costs and time in manufacturing, as well as possibly causing negative effects to the product itself.
Equally under-drying will result in product spoiling and poor aesthetic qualities.
Therefore, determining the 'ideal' drying cycle is the key to this application.
Cooled Mirror dew point sensors are used in the coating process to measure the dew point or absolute humidity of the inlet and exhaust of the drier.
This type of humidity sensor, such as the one used in the Optidew, is typically used because of the fundamental nature of the measurement and its drift free characteristics.
The high performance optical dew point transmitter works on the proven dew point measurement principle offering the user unmatched performance, ease of maintenance and zero drift.
This has led to a number of world leaders in the manufacturing of pharmaceutical and confectionary products moving over to this technology.
The Optidew offers a wide measurement range from the equivalent of <0.5 to 100% RH at ambient temperatures and from -40 to +90C.
The Cooled Mirror instrument also provides two linear 4-20 mA outputs in addition to serial communications, allowing set-up and monitoring by a suitable computer or PLC system via specific Optidew logging software.
An adjustable volt-free contact alarm means Optidew can be used for direct process control.
An optional high definition alphanumeric display provides local indication of the measured humidity.
If you would like any further information about the Michell Instruments Optidew, or any of the instruments in the Michell Cooled Mirror range request a brochure or contact Michell direct. Request a free brochure from Michell Instruments ...
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