The use of offset water-closets is a practice more or less common, but now generally prohibited by plumbing ordinances. This form of water-closet bowl has no trap, but its shape is such that the uninformed person would not generally detect the fact. It is generally used to replace one of the old-time styles of water-closets which depended upon a lead or iron trap below the floor.
Instead of tearing out both closet and trap, the latter is often allowed to remain, and the fixture replaced by an offset bowl, as in Fig. 157. The objections to this course are so apparent as to need no explanation.
The only proper course under the circumstances, is to replace the old fixture and its separate trap with a modern water-closet having the trap within the bowl.
Thus far nothing but tank water-closets have been considered in this chapter. Within the last decade, however, another method for the flushing of water-closets has come into extensive use, which does away entirely with the use of flush tanks.
The device in question is known as the flushing valve, and is made in various forms by the different manufacturers, one of them being shown in Fig. 158.
Flushing valves are also much used in connection with urinals and slop sinks. Their use thus far has been confined largely to public buildings and large work of a high grade, although in nice residence work they are also being used extensively. The flushing valve is an automatic, slow-closing valve, operated generally by means of a lever or a push button. Although the action of the different valves varies greatly, in general it may be said that its action is as follows:
Fig. 157. - The Prohibited Offset Water-Closet.
When the handle or push button is released after the fixture has been flushed, the flushing valve closes automatically by means of the action of a jet or stream of water, issuing from the pressure side of the valve, which passes through a by-pass into the chamber beyond the piston-head, which is thereby forced onto its seat.
The flushing valve may be worked under direct pressure, or under tank pressure. The latter is preferable to direct pressure for this work, as tank pressure is always more uniform than direct pressure, and more positive.
The various makes of flush valves are advertised to work under various pressures, certain types being guaranteed to operate satisfactorily through a wide range of pressure, while other makes are constructed in several patterns, each being adapted to pressure of certain limited range. Generally speaking, however, it may be said that the flushing valve must be provided with a pressure of 10 or 12 pounds to work satisfactorily.
Fig. 158. - The Flushing Valve, - Double-Jet Siphon Water-Closet.
The size of supply pipe for the various makes of flushing valves and for the various pressures varies from 1 inch to 1 1/2 inch. The action and construction of these valves is so different that it is impossible to give exact data without knowing the make of the valve that is in question. Therefore in installing them, it is desirable to secure from the manufacturer the working data and instructions for connecting them under the conditions respecting pressure, number of valves on the system, etc.
In connection with the illustration of the flushing valve shown in Fig. 158, a sectional view of a double-jet siphon water-closet is given. This type of siphon-jet closet is not common and should be of interest to the reader.
It will be observed that one of the jets enters the bowl at A and the other at B, the former throwing a stream of water down the outlet leg, and the latter throwing a stream in an upward direction through the rising leg of the trap. By adding the jet A, the air is driven out of the discharge leg, thus removing the resistance to the jet B.
It would seem that the combination of the two jets must result in a very strong siphonic action, stronger than that obtained in the regular siphon-jet closet.
It is claimed by the manufacturers that this water-closet is designed especially for low-down use, that because of the lack of pressure, due to placing the tank so close to the bowl, much objection to an inefficient siphonic action has been found, which the use of an additional jet has overcome. The jet A is securely trapped. Otherwise, gases from the drainage system might pass up through the discharge leg, into the jet, and thence into the room through the flushing rim.
The frost-proof water-closet is a fixture thus far unmentioned, for which there is a considerable demand under certain conditions. It can readily be seen that it is not possible to use the ordinary water-closet bowl and flush tank in any place that is exposed to freezing temperatures, for the reason that the water in the closet trap would freeze and burst the fixture, and the same thing would happen to the flush tank.
Accordingly, whenever it is necessary to install the water-closet in cold places, the frost-proof type of closet must be used. One form of this fixture is shown in Fig. 159.
As a bowl with the trap included in it cannot be used, a hopper closet is generally employed, protection against the entrance of gases being afforded by a trap placed below the fixture, sufficiently to be below the freezing point. The supply valve is also of necessity placed below the freezing point.
When the seat is occupied, the flush tank fills, due to the opening of the supply valve by the attached mechanism. When the seat is released, the supply valve closes, and the contents of the flush tank discharge into the closet. After the flushing has taken place, the water remaining in the pipe above the valve, drains of into the water-closet trap, through a small drain tube.
Fig. 159. - Frost-Proof Water-Closet.