Digital counter for displaying the amount of air sampled during a sampling period based on an analogue display meter with rotating counter wheels, the rotation of which is optically sensed and used with the digital display

摘要

Meter (1), especially Gallus type meter, has a digital display (14) showing the amount of gas that has been sampled since it was last zeroed. The meter has an output in the form of counter wheels, the rotation of which is proportional to a calibrated volume of air. The meter has an infrared reflection sensor that (2) that transmits to a counter impulses representing the volume of air passing through the counter.