It is often desirable to provide groups of such fixtures as water closets and urinals with automatic flushing, such provision being specially valuable in school and factory use, and often in public work, such as railway-station toilet rooms, public comfort stations, etc. In the use of any toilet room for the accommodation of the public, the fixtures are bound to be used by many people who are ignorant or careless in the matter of flushing fixtures after having used them. In the matter of urinals, especially, the flushing of them is often left to the attention of an attendant who may be careless in performing this duty. In school houses particularly, small children using the fixtures cannot always be expected to understand the necessity of flushing water closets. Owing to these circumstances and many others, the periodic and automatic flushing of fixtures is of much advantage in maintaining wholesome toilet rooms.

Plate XLI. Automatic Flushing For Schools Factories, Etc

Plate 41. Automatic F/ushing for Schools Factories, etc.

Automatic Flushing For Schools Factories Etc 104

Fig A.

Automatic Flushing For Schools Factories Etc 105

Fig B.

Automatic Flushing For Schools Factories Etc 106

Fig C.

In Fig. A, Plate 41, is shown a sectional view of a form of automatic flush tank, the action of which is as follows:

The admission of water to the automatic tank is not controlled by ball cock, as the supply must be constant. The interval between flushes depends upon the amount of water flowing into the tank, which is regulated by the valve G. The principal working parts of the flushing device consist of a circular vessel D, which is supported by several wires attached to the outer circular compartment B. The vessel D, is filled with water, into which a tube C, projects. Outside of C is a hollow cylinder H, closed at its upper end, and supplied with holes at the bottom, through which the water may enter. As the water rises in the tank, it fills the space between the tubs C and the cylinder H, the air in the tube and at the top of the cylinder being confined between the rising level of the water and the water seal of D. This air becomes more and more compressed as the water rises, until the pressure exerted is sufficient to force the water out of D. This produces a vacuum at the bottom of the tube, and the compression being relieved, atmospheric pressure on the surface of the water in the tank will force it into the tube C, and into the flush pipe A, which conveys it to the different fixtures to be flushed.

This siphonic action continues until the water in the tank drops to such a point that air is admitted through the holes M, when the action stops, the tank again beginning to fill for the next flush.

Fig. B shows the general plan of connections between the tank and the fixtures.

The principles governing the construction, locating, etc., of storage tanks also apply to automatic flush tanks, and are to be found under Plate 39. Successive flushes should not be more than seven minutes apart. A great objection to automatic flushing is that whenever water closets or urinals are used, the excreta entering them must remain in the fixture, giving off impure odors into the toilet room, until the next flush takes place. For this reason it is necessary to provide each water closet and each urinal of an automatically flushed system with strong-acting local vents.

The automatic flush tank should be of sufficient size to discharge into each fixture at least four gallons of water at each flush. The copper lining for the automatic flush tank, and for all other flush tanks, should not be less than 10 ounces. This weight is ordinarily used for tank linings, but a heavier grade of metal is preferable.

Another disadvantage in the use of the automatic flush tank is the large amount of water used, which is a matter of importance if a metered public supply is to be used, owing to cost of water. In many instances however, institutions, factories, and hotels have a large private supply, the use of which is not restricted. When used in connection with many systems, the periodic flushing must go on without interruption, but in the case of school buildings the supply to the tank may be shut off when school is not in session. In connection with plumbing systems automatically flushed, water closets and urinals in private toilet rooms and bath rooms may not be connected to the automatic flush if it is desirable to keep down the cost of water used.

Fig. C, Plate 41, shows a form of automatically flushed urinal, of excellent design.

It is made of porcelain, or porcelain-lined material, is free from exposed metal parts which may corrode, and is well adapted to public toilet rooms.

A cross section of a urinal of this type may be seen in Fig. E,

Plate 43, from which it will be observed that a large body of water always stands in the fixture, the tank after completing its flush always providing this body of water, which stands in the urinal until the succeeding flush. A double trap is provided on the outlet of this urinal, one trap being above the other: When the tank flushes, the air in the upper trap becomes rarefied - that is, partially exhausted - sufficiently to set in action a strong siphon which draws the entire contents of the urinal out of the fixture and into the waste. When the water in the tank drops to a certain level, air is admitted to the pipe running from the tank to the crown of the upper trap, the admission of this air to the trap breaking the siphon.

When the siphon breaks, the water at that time in the urinal, remains there until the next flush. No water is wasted in starting this siphon, every drop of water passing out of the tank being used in cleansing the fixture. A horizontal perforated pipe at the back of the urinal, and connected with the vertical flush pipe from the tank, thoroughly flushes and cleanses the back of the urinal. This same action is applied in the flushing of water-closet ranges. Both range and urinal can be installed of any number of compartments and supplied with a tank of size to correspond.

Slop sinks, in addition to water closets and urinals, may be automatically flushed.

There is a sink for factory use, made of slate, or wood lined with sheet copper, and of any desired length, which is comparatively self-cleansing.

The sink is made with an outer and inner compartment, the latter running through the center of the sink, with space for washing on either side. There is also a narrow space at the end of the inner compartment, between it and the outer compartment, in which a standing overflow is located, connected into the waste. A line of supply pipe runs above and over the center of the sink, and is provided with sprays which throw the water down into the center compartment, from which it overflows into the main body of the sink. Thus the first washing may be done in the outer compartment, with clean water always in the inner compartment for use in face washing.

In factories employing a high grade of help, the line or battery of lavatories shown in Fig. A of Plate 37, and Fig. E of Plate 38 is much in use.