Michell Instruments - Moisture and Humidity Measurement Solutions

Michell Instruments is the international leader in the field of moisture and humidity measurement solutions. With over 30 years of experience, Michell designs and manufactures a wide range of transmitters, instruments and system solutions capable of measuring trace moisture, humidity and dew point in a vast range of applications – including many in the pharmaceutical industry.

With a fast-growing international subsidiary and distribution network, the Michell group provides solutions in dew point, moisture and humidity to the most demanding applications worldwide.

Drying and tablet coating

Producing a smooth, even coating on tablets relies on controlled levels of humidity during the drying process. Basing the drying cycle on actual levels of moisture in the dryer for producing a high-quality product as well as saving energy, speeding up production and reducing waste.

Two sensors are needed for this – one to monitor the air going into the dryer, the other to measure the moisture in exhaust air leaving the dryer. The two measurements are fed into the process system, and the drying cycle adjusted to the optimum time.

A sensor such as Michell’s Optidew high performance optical dew-point transmitter would give drift-free long-term performance in this type of application. It offers a wide measurement range from the equivalent of <0.5% to 100% rh at ambient temperatures from -40°C to +90°C.

Environmental control sensors

Handling powders requires finite control of humidity to avoid clumping or deterioration. The output of the moisture sensor feeds directly into the HVAC system and can give warning alarms if the humidity rises above a certain level. Keeping moisture levels low is also essential to control bacteria growth.

Michell’s range of % RH sensors provide a quick and easy method to monitor the levels of relative humidity during production, packaging or storage of pharmaceuticals. For more accuracy, a chilled mirror product, such as the Optidew, can also be used.

Compressed air monitoring transmitter

Compressed air is used in a number of manufacturing processes. Ensuring that the supply of air is dry is essential to avoid raising moisture levels in the product or the environment as well as avoiding the growth of bacteria in supply pipes.

The Easidew transmitter is designed for ease of use, incorporating all the features needed to make installation and operation as simple as possible as it can be instantly incorporated into the air management and control system. Low dewpoint specifications can be maintained as the sensor is capable of measuring levels of moisture down to -100°C (>0.14ppmv)

Calibration of control instruments

Critical processes, such as manufacturing pharmaceutical products, require the control instruments to be calibrated on a regular basis as a legal requirement. Although Michell offer a full calibration service for their instruments their range of moisture sensors offers manufacturers the choice of calibrating sensors in-house.

Michell Instrument manufacture a range of humidity calibration systems, from simple bench-top units to PC-controlled humidity chambers.

The Opti-Cal is a bench-top, fully self-contained humidity / temperature calibrator designed for users of relative humidity sensors. The system comprises a humidity and temperature-controlled chamber that can house up to five or more humidity sensors, depending on their physical dimensions.

The humidity and temperature within the chamber are closed-loop controlled and continuously monitored by a precision chilled mirror reference hygrometer. The Opti-Cal works by time proportioning the flows of dry and saturated air according to the pre-selected relative humidity value.