Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

A self-monitoring carbon monoxide filter unit for employees who work in atmospheres containing carbon monoxide

A self-monitoring carbon monoxide filter unit was developed to increase safety for employees who work in atmospheres containing carbon monoxide near blast furnaces and other metallurgical facilities. This was accomplished by integrating an electro-chemical sensor between the filter box and the respiratory connection, objectively indicating the efficiency of the filter box, its service life and the limits of use to the user. The break-through of a filter box and consequently its rejection is indicated threefold after a concentration of 30 or 60 parts per million carbon monoxide is reached in the inhalation air: optically by means of a light emitting diode (LED) acoustically by means of an intermittent alert signal (depending on concentration) by increased inhalation resistance due to the closing of a reducing damper in the inhalation air channel. Considerable increase of filter capacity utilization proved that the microelectronic unit responsible for device safety was economically efficient. The service life of the electro-chemical sensor proved to be excellent. After a current maximum service life of 5 years, about 80% of the total of 150 monitoring units which have been in continuous operation are still fully operative. The practice of changing the microelectronic units at the collecting points at weekly intervals with subsequent check, calibration and re-charging of the accumulator batteries has met with unreserved success. It has to be noted as a restriction that the use with gases containing not only carbon monoxide, but also a high portion of hydrogen (such as coke oven gas) is not appropriate due to the sensor's transverse sensitivity to hydrogen (the alert threshold is reduced too much by premature response of the sensor). This measuring principle basically works with any kind of gas filter.

Reported by

Preussag Stahl AG
Eisenhüttenstraße 99
38239 Salzgitter
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