| 摘要 |
A compressed air line is provided with a coupling, including a shutoff valve for receiving a transparent, lineal, tubular member having a bore of relatively small diameter through which the compressed air is allowed to bleed to atmospheric pressure. The rate of bleeding is calibrated by means restricting the flow of air through the lineal member. The input end of the lineal member into which the air enters is provided with a coloring stage including a dye for coloring contaminates in the air. A contaminant adsorption stage of polyethylene of small micron size fills the remainder of the lineal tubular member. Bleeding of the gas to atmosphere at high velocity through the relatively small metered input to the tube causes the gas to expand suddenly by orifice action. The high velocity flow and rapid expansion of gas causes any vaporized contaminant particles to pick up dye, preferably bright red, as they flow through the coloring stage. The gas then flows at high velocity through the adsorption stage, creating sufficient turbulence to cause coalescence into colored drops which adhere to the polyethylene showing a progressive travel of color through the transparent lineal member with minimal loss of compressed gas in accordance with the amount of contaminant in the air. The rate of such color travel is calibrated and a scale along the length of the lineal member provides an output reading of the contamination in parts per billion sensitivity which may be read either directly in inches or in ounces of contamination per 100,000 cubic feet of air volume, depending on the scale used.
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