E.i. Dupont De Nemours and Company

W Barry Baker

Harry Edwards Betsill

Donald G Clark

John Charles Kochur

Estel McKinley Stoneman

An improved pump unit for sampling air that operates at a constant air flow rate in the range of 5-5000 cc/min. having a filter for removing particles or vapors from the air stream, an air accumulator, a variable drive pump optionally with a bypass, an electric motor for driving the pump, an optional air reservoir, an orifice which creates a pressure drop in the air stream, an optional bypass for the orifice and a pressure switch connected in parallel to the orifice which monitors a change in the air pressure drop; the improvement in the pump is the use of a digital circuit electrically connected to the pressure switch and a closed loop control means electrically connected to the digital circuit and motor; a digital signal determines the open or closed position of the switch and the control means and allows current to flow or not flow to the motor driving the air pump to provide a constant flow of air through the unit; the pump unit is worn by a worker or is placed in a work area and at the termination of a period of time, such as a work day, the filter is removed and the contents collected are analyzed by conventional techniques such as gas chromatography to determine a level of exposure of the individual or the level of exposure of people working in that area.

Pump unit for sampling air

An improved chemical dosimeter for individual use which collects on a filter particles or vapors present in an air stream which is being pumped through the dosimeter at a constant rate, the improvement is the use of

Chemical dosimeter having a constant flow air sampling pump

An improved apparatus for feeding fuel to an internal combustion engine, said apparatus comprising a multiplicity of fuel sources that cooperate with a spill chamber that is surrounded by an overflow trough. Cooperation is by means of a feed line having an on-off valve along its length. The spill chamber feeds fuel to a fuel/air mixer that cooperates with the engine. The improvement comprises (i) a structural relationship between feed line, on-off valve and fuel flow in that the on-off valve is positiond in the feed line so that fuel is forced in a direction generally away from gravity immediately before and after passing through the valve and (ii) the feed line is fixedly positioned to direct fuel into the chamber when the valve is 'on' and into the trough when the valve is 'off'. The invention also concerns an apparatus for measuring fuel octane numbers that incorporates the feeding apparatus just described.

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Newark, DE, United States of America

W Barry Baker