Peter C Raynor | PubMed Health

PubMed2005

Mist generation from metalworking fluids formulated using vegetable oils.

Metalworking fluid emulsion formulations produced from vegetable oils may be less toxic and may reduce disposal costs when compared with fluids formulated with petroleum-based oils. Experiments were performed on experimental emulsions made with unmodified and modified soybean oils to measure rates of mist production by impaction, centrifugal force and evaporation/recondensation mechanisms. Results were compared with measurements made using a commercial metalworking fluid emulsion formulated using vegetable oil and another made from mineral oil. The results indicated that most of the experimental fluids produced about the same amount of mist as the commercial fluids by impaction and more mist than the petroleum-based fluid by centrifugal force. However, an air-oxidized modified soy oil produced less mist by impaction than the petroleum-based fluid and about the same by centrifugal force. The experimental fluids produced between 30 and 90% less mist than the commercial fluids by evaporation/recondensation. The air-oxidized soybean oil was the most promising candidate among the experimental fluids for further testing in more realistic machining conditions.

Air Pollutants, Occupational↗

PubMed2004

The long-term performance of electrically charged filters in a ventilation system.

The efficiency and pressure drop of filters made from polyolefin fibers carrying electrical charges were compared with efficiency and pressure drop for filters made from uncharged glass fibers to determine if the efficiency of the charged filters changed with use. Thirty glass fiber filters and 30 polyolefin fiber filters were placed in different, but nearly identical, air-handling units that supplied outside air to a large building. Using two kinds of real-time aerosol counting and sizing instruments, the efficiency of both sets of filters was measured repeatedly for more than 19 weeks while the air-handling units operated almost continuously. Pressure drop was recorded by the ventilation system's computer control. Measurements showed that the efficiency of the glass fiber filters remained almost constant with time. However, the charged polyolefin fiber filters exhibited large efficiency reductions with time before the efficiency began to increase again toward the end of the test. For particles 0.6 microm in diameter, the efficiency of the polyolefin fiber filters declined from 85% to 45% after 11 weeks before recovering to 65% at the end of the test. The pressure drops of the glass fiber filters increased by about 0.40 in. H2O, whereas the pressure drop of the polyolefin fiber filters increased by only 0.28 in. H2O. The results indicate that dust loading reduces the effectiveness of electrical charges on filter fibers.

Air Pollution, Indoor↗