A PORTABLE SELF-CLOSING HYDROGEN SULFIDE DISPENSER* University of Wisconsin, Madison, Wisconsin
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N RESPONSE to frequent requests for iuformation concerning the portable self-closing hydrogen sulfide dispensers in use a t the University of Wisconsin, the author, who designed the portable feature in order to allow the dispensers to be used in an openfront baffle-plate hood of the "Cornell University" type, submits the following description. The use of these dispensers, and enforcement of a regulation that all reactions with hydrogen sulfide be carried out in closed vessels, has enabled a large modern laboratory filled to capacity (ninety-six students) to be kept free from the odor of hydrogen sulfide. The frame of the dispenser is of wood. The door is
cloth. The gas cock and the hose nipple are onequarter-inch brass. All other piping is black iron, the interior surfaces heavily coated during assembly with a mixture of graphite and lubricating oil. All other metal parts, except the steel springs, are black iron. After fabrication, two coats of an acid-proof asphaltum paint were applied to the entire apparatus except the springs, flow adjusters, and adjuster guides, which were coated with the graphite-oil mixture. The flow of gas can be set a t any volume, including full flow, by controlling the travel of the lower extension on the handle of the gas cock, this travel being regulated by two movable collars on the inner end of the
flow adjuster. Straight line movement of the adjuster, obtained by the adjuster guide, insures complete clos'Presented before the Division of Chemical Education ing of the cock as soon as the pressure is removed at the ninety-third meeting of the A. C. S., Chapel Hill, N. C., from the wooden knob on the outer end of the flow April 14, 1937. t Present address: 3105 Cross Street, Madison, .wisconsin. adjuster. The guide also serves as a stop for the lower 391 covered with plywood and the back, bottom, end, and top panels with number four galvanized hardware
handle extension of the gas cock, thereby keeping the spring attached to the upper handle in tension and the cock closed except when in use. The hose nipple passes through the lower cross bar of the frame and projects not more than three-eighths of an inch below its under surface, to prevent submerging the outlets of the nipples in solutions being tested. With a central supply of gaseous hydrogen sulfide available, each dispenser is connected directly to an offtake from the supply main through a stopcock and union, so that a dispenser, which weighs about twenty pounds, may be easily disconnected and set away when not needed. Since there is ample space within a dispenser for installing a small cylinder of liquid hydrogen sulfide
and the necessary pressure reducing valve, it may be used as an independent portable unit. Just before the beginning of the semester the gas cocks are taken apart, cleaned, inspected, and lubricated with the graphite-oil mixture, and the gas flow is adjusted. This, with a second inspection about the middle of the semester, has constituted all the attention required by three of these dispensers used for over eight years by classes averaging three hundred students each, an excellent record of durability due to the faithful work of Mr. Ernst Dangl* in fabricating and inspecting the dispensers. Definite data are not available concerning the cost of a dispenser, the work having been done a t odd moments. * Deceased.
