Text-book of hygiene; a comprehensive treatise on the principles and practice of preventive medicine from an American stand-point (1908) (14802271293)

Identifier: textbookofhy00rohg (find matches)
Title: Text-book of hygiene; a comprehensive treatise on the principles and practice of preventive medicine from an American stand-point
Year: 1908 (1900s)
Authors: Rohé, George H(enry), 1851-1899. (from old catalog) Hygiene. (from old catalog) Robin, Albert, 1875- (from old catalog)
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Publisher: Philadelphia, F. A. Davis company
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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pe) of the trap is diminished, or, on the other hand,by increase of pressure in the soil-pipe the water in the trap may beforced back into the fixture, and thus sewer-air enter the room. Byproviding for a free entrance and exit of air to the trap this break-ing of the seal can be prevented. The ventilation of traps is, however,an evil, as it furnishes an additional means of evaporation, and when HOUSE-DRAINAGE. 213 the fixture is not in frequent (daily) use the seal is sooner broken.The elaborate extra system of ventilation of traps, so generally insistedupon by plumbers and sanitary engineers, is unnecessary. If the soil-pipe is of the proper size and height, siphonage of traps will not belikely to occur. The waste-pipe connecting the fixture and the soil-pipe should be as short as possible; in other words, all water-closets,urinals, baths, and lavatories should be placed as near the soil-pipeas practicable, in order to have no long reaches of foul waste-pipeunder floors or in rooms.
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Fig. 22. Fig. 23. Fig. 22.—Sectional View of Vent, with Cap in Normal Position. Fig. 23.—Sectional View of Vent, with Cup Lifted out of the Mercuryby the Inflowing Current of Air Indicated by the Arrows. Dr. E. S. McClellan has recently invented a trap which obviatesmany of the objections urged against all previous devices, and isintended to meet the defects of the S and other traps. It consists ofa body containing a light, inverted cup, with its edges resting in anannular groove containing mercury, which forms an absolute sealagainst the escape of sewer-air. When a slight diminution of pressureoccurs on the sewer side of the cup, the greater external pressure liftsthe cup out of the mercury and permits a free inflow of air until thewonted equilibrium is re-established, when the cup drops back intothe mercury by gravity, and effectually closes the trap against any 214 TEXT-BOOK OF HYGIENE. outflow. With this trap siphonage of the seal is impossible. Fig.22 Bhows this trap with the

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