Practical Method for Obtaining Dry Air for Humidity Control in a Rubber Laboratory
Abstract THE effect of relative humidity on rubber-testing has been the subject of much recent investigation. String-field and Conover and Depew have published papers on this subject. The last-named authors recommended that the rubber be stored in dry cabinets before milling, between milling and vulcanization, and between vulcanization and testing, at a temperature of 75° ±5° F. A short time later the Physical Testing Committee of the Rubber Division of the American Chemical Society recommended that all laboratory testing be carried out at 45 per cent relative humidity and 82° ±5°F. While both methods have undoubted merit, it was believed that for physical testing laboratories, particularly such as this one, zero humidity was both more conducive to reliable results and easier to maintain. Accordingly, equipment was installed for maintaining zero humidity and its performance has been consistently good. Since several of the larger rubber laboratories have shown interest in the equipment, it has been decided to present this description of the installation and its operation.