Single urinals are usually of porcelain, although some have been made of iron. The common types are plain or lipped, made in flat-back and corner designs. Flat-back types of both de signs are shown in Fig. 48. All have flushing rims. Direct-flushing valves of the same type as used on closets, adapted to the purpose, and cocks of various types, are the means of flushing generally pro vided for a single urinal. When two or more are placed in one room, an automatic tank with branched flush pipe is ployed. These tanks are of greater variety than those used with range closets. T h e tilting bucket, pivoted within a tank case, which empties itself periodically by means of the flow of water changing the center of gravity to the supported side and tipping it just before it overflows, is a familiar type of automatic urinal-flushing tank. The standard tank with immovable parts, which siphons automatically, is also prevalent. Examples of these types are illustrated in section in Fig. 49.
Another design consists of a tank withcommon siphon, fitted with a ball cock which opens, instead of clos ing, as the water in the tank lifts the ball.
The interval between flushes is governed by a small Bibb c o c k, which may be turned on more or less so as to take greater or less length of time for the water in the tank to reach the ball. When water begins to lift the ball, the ball cock also admits water. From this point the tank fills rapidly. The higher the ball is lifted, the faster the tank fills, so that by the time the water-level reaches a point where water begins to flow over the neck of the siphon, it is coming into the tank rapidly enough to more than keep pare with the overflow necessary to start the siphon.
True siphonage, however, empties the tank much faster than the sup ply can fill it; and the tank is soon empty, leaving the small bibb cock to admit water again slowly to where this action can be repeated.
Individual urinals which siphon by admitting additional water to that which normally stands in the fixture, and various other types, will be best understood from a study of dealers' catalogues. In good work, marble backs and partitions usually enclose the urinals on three sides. Marble and slate stalls of various construction, with channeled and guttered floor, as shown in Fig. 50, all washed by perforated pipes fixed along the surfaces, are frequently used in lieu of specific urinal fixtures. A thick base of slab material is sometimes used, the gutter and drain-hole being cut in it. Cast-iron gutters, galvanized or enameled, with an outlet-end adapted to a soil-pipe connection, are supplied by the makers.
In describing the fixtures and trimmings that have been noticed, only salient features of form and principles of design have been con sidered. Sufficient guidance to insure intelligent comparison of merits and skilful discrimination in selection, has been given. Cata logue detail and illustration, and a view of the actual goods described therein, should, with what has now been given, insure the fullest understanding of the fixture branch of Plumbing.