International Safety Instruments, Inc.

Victor Speck

R David Lewis

Paul D Hiltman

Robert E Gray

A self contained breathing apparatus has a display of air pressure within the face mask in the field of vision of the user of the breathing apparatus. The display is four lights that indicate the four quarter-tanks of pressure, and the lights change to indicate the amount of air remaining. A transducer receives tank pressure and provides an electric signal. The air pressure is placed on a bourdon tube which rotates a disk in response to changes in pressure. One half of the disk includes a gradient, and a light source emits light through the gradient to be received by a light sensor. As the disk rotates, the gradient varies the amount of light received by the sensor, so the electrical output of the sensor varies.

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Atlanta, GA, United States of America

Victor Speck