Hydrogen Sulfide NX169L Detector Tubes (1-60 ppm)
1 to 2 ppm = 2 pump strokes (200 ml)
2 to 20 ppm = 1 pump stroke - (100 ml)
20 to 40 ppm = 1/2 pump stroke - (50 ml)
* Color change: White -> Brown
* Shelf Life: 3 years
* Pack/10 tubes
Each Gastec detector tube contains a reagent that is specifically sensitive to a particular vapor or gas. These reagents are on fine-grain silica gel, activated alumina or other absorbing media (depending upon application requirements), inside a constant-inner-diameter, hermetically sealed glass tube. Gastec detector tubes are the "direct-reading" type, with calibration markings right on the tube, so measurements can be made as simply and precisely as reading a thermometer. The actual operation is simple and accurate. Just snap off both "break-away" ends of a tube in the convenient tube-tip breaker, insert the tube into the handheld pump, and pull out the pump handle. As the handle is pulled (just like a syringe), a precisely measured volume of ambient air is drawn inside the tube where it contacts the reagent. Instantly, the reagent changes color. The reagent reacts quantitatively to provide a length-of-stain indication. The farther the color stain travels along the tube, the higher the concentration of gas. Note the calibration mark on the tube at the point where the color stain stops and that is the measurement.