Michell MDM300 portable dewpoint hygrometer

Michell’s MDM300 portable dewpoint hygrometer takes high-speed measurements of moisture in compressed air systems for surgical instruments and breathing air in spot checks to ensure safety in hospitals.

Compressed air is used throughout hospitals for breathing air and instrument air. As with all compressed air systems, keeping moisture levels low is important to avoid corrosion, as well as reducing the risk of bacteria growing. Bacteria can easily grow in water vapour in compressed air lines, from where they may be released into the air where they can either grow on surfaces or be breathed in and possibly cause infection. The warm conditions of a hospital provide good conditions for bacteria to thrive if not kept clean and dry.

To remove the risk of bacterial growth, it is vital to keep the compressed air at a dewpoint of less than -46°C. The portable hygrometer provides peace of mind that the moisture level in the compressed air is at, or below, this dewpoint temperature by enabling spot checks to be made at critical points in the system. Each portable hygrometer undergoes a 13-point calibration over 10 days before leaving the factory. For reassurance of accuracy, the calibration certificates are traceable to the National Physical Laboratory (NPL) for the UK, or National Institute of Standards and Technology (NIST) for the US - the key measurement standards authorities for these regions. Accredited calibrations to ISO 17025 are also available.

The device is capable of taking measurements on breathing air or surgical air at line pressure with a simple sampling kit - the Medical Air kit. This allows the hygrometer to connect directly to the bulkhead system with a standard 3/8″ NGS probe. Because the MDM300 needs no waiting time between measurements - even to very low dewpoints - a large number of spot checks can be carried out each day. The instrument is easy to use, with an intuitive interface which needs the minimum of training to use. The device gives ±1°C accuracy down to -60°C dewpoint.