It will thus be seen that when the fixture is not in use, there is no water standing in the flush tank, or at any point in the piping above the supply valve. It is needless to say that this form of water-closet work would not be considered sanitary under ordinary conditions, but under freezing conditions, as found in outhouses, sheds, etc., which are not attached to dwelling houses, such work is the best that can be made of a difficult situation. There are other forms of frost-proof water-closets, in connection with some of them the tank being placed below the water-closet. When so placed, the head due to the elevated tank is lost.

In order to provide sufficient pressure to force the water into the closet bowl, otherwise than under direct pressure, the flush tank is made to act as a pressure tank. When the seat is occupied, the water passes into this tank, compressing the air held in it, until the compression is sufficiently high to prevent its further entrance. When the seat is released, a weight attached tips it up, closes the inlet valve, and opens the discharge. The compressed air of the tank forces the water up and through the water-closet bowl, under about the same pressure as the direct supply.

In many instances, in plumbing systems for such buildings as schools, factories, etc., the range water-closet has in the past been used to some extent.

While the range water-closet is not to be compared to the individual water-closet, as to sanitary excellence, it is a fixture that is in quite extensive use, and therefore deserves attention. The old-style range was a filthy affair, but the present, high-grade makes are far superior in every respect. They are now made of porcelain or enamel-lined, there being no exposed metal surfaces, and otherwise constructed and provided with features which go far toward making this fixture of as high a standard of excellence as it is possible to secure under the conditions that must naturally surround it.

In Fig. 160 is shown one of the modern types of range water-closets, most of which are now operated by means of an automatic flush tank, combined with a strong-acting siphoning apparatus. The tank is connected to the siphon by means of an air pipe. When the tank operates, the flush exerting its influence through the air pipe, exhausts the air in the upper trap to a certain extent, thereby forming a partial vacuum. The result of this action is that the atmospheric pressure exerted on the surface of the water standing in the opening from the range into the trap, sends the water forcibly over into the trap, filling it, and producing siphon-age, which quickly discharges the contents of the range. After this operation ceases, the range fills to its regular height and is again in readiness. The automatic flush tank may be regulated to flush at any desired interval. Each bowl is thoroughly flushed and cleansed at each flush, and the flush from the tank being also connected to the end of the range waste, adds much to rapid discharging of the contents of the range.

Fig. 160.   Modern Range Water Closet.

Fig. 160. - Modern Range Water-Closet.

One of the chief objections to the old-style range water-closet, is that it was poorly flushed. This objection, then, has been very largely removed in the best makes of the present day, the flushing and scouring features of such fixtures as that shown in Fig. 160, being very satisfactory.

Another feature that has always been very objectionable in this fixture, is the fact that the waste matter entering the range has given out into the room through the seat openings, a constant stream of foul odors, between successive operations of the flush. This has been very largely overcome by the employment of efficient local ventilation. The subject of local ventilation, by the way, is considered at length in the following chapter.

In the range shown in Fig. 160, it will be observed that each bowl is provided with a local vent connection of large size. These are carried into a ventilating duct which should connect into a well and constantly heated flue.

When a strong ventilation is thus provided, it results in reducing to a minimum, the objection above mentioned, due to the standing in the bowls of the waste matter. Whenever it is possible, a special flue should be provided for ventilating purposes, which should be heated especially for this work, if need be.

In connection with some forms of range water-closets, in which separate bowls are not used, the ventilation for the fixture is provided by a single large pipe attached to the end of the range.

It would appear, however, that the individual local vents are the most direct in their action, and therefore the most efficient. It will thus be seen that the modern range water-closet, constructed of high grade, noncorrosive material with separate bowls, thoroughly flushed, as described above, and provided with strong ventilation, is a far superior fixture to the old type - much more sanitary and satisfactory in every respect