Abstract: An improved pump unit for sampling air that operates at a constant air flow rate in the range of 5-5000 cc/min.

Abstract: 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 ofA variable drive pump that is connected to the filter and that is driven by an electric motor and is controlled by a feed back circuit of an integrator and an amplifier and maintains a constant flow of air through the dosimeter;The integrator receives a signal from a pressure switch that detects changes in the flow of the air stream through the dosimeter by a change in a pressure drop of the air which is being pumped through an orifice;The dosimeter is worn by an individual and at the termination of a period of time, such as a work day, the filter is removed and the collected contents are analyzed by conventional techniques such as gas chromatography to determine a level of exposure of the individual using the dosimeter.

Abstract: 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.