E.i. Dupont De Nemours and Company

William B Baker

Harry Edwards Betsill

Donald G Clark

Joe T May

An audio dosimeter for use by an individual for measuring exposure to sound which contains the following components:

Audio dosimeter

An apparatus that measures light transmitted through a fluid sample and provides a direct readout of such a measurement by electronically converting light transmitted to an electrical signal that is displayed on a readout device; the apparatus contains a power source, a light source, a photodetector, a sample holder for samples that forms a cell; the improvements used in the apparatus are as follows:

Direct readout apparatus for measuring light transmitted through liquids

An improved dosimeter designed for individual use that has a filter for collecting particles or vapors present in an air stream being pumped through the dosimeter, a variable drive pump that draws the air stream through the filter, an electric motor coupled to the variable drive pump, an electric power source for the motor, an air reservoir connected to the pump, an orifice position in a tube attached to the air reservoir which creates a pressure drop in the air stream, a differential pressure switch positioned before the orifice that is activated by a change in air pressure and creates a low voltage electrical input signal; an integrator circuit that uses the low voltage input signal of the pressure switch and integrates this signal, an amplifier circuit which amplifies the signal from the integrator circuit and feeds the signal to the electric motor thereby controlling the speed of the motor driving the pump in relationship to the signal generated by the pressure switch to maintain the air stream at a constant flow rate; the improvement that is used therewith is as follows:

Dosimeter having constant flow pump

An improved dosimeter for monitoring working areas in which air, preferably in a relatively large volume, is pumped through the dosimeter at a controlled constant flow and any particles or vapors in the air are collected on a filter, the improvement is the use of

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Newark, DE, United States of America

William B Baker