Practical Methods of Sewage Disposal for Residences, Hotels and Institutions

by Henry N. Ogden; H. Burdett Cleveland

Fig. 15.—Flap Valve Attached to Length of Sewer Pipe.

Fig. [17] shows another form of this same sort of valve, taken from the catalogue of the Adams Hydraulic Company, and noteworthy because of the loose-link connection at the upper part of the valve, the object of this being to prevent the valve closing at the upper part without, at the same time, closing at the bottom.

If the dosing tank is to work automatically and independently of human agency, an arrangement which is always preferable, there must be installed some mechanism which takes the place of the valve operated by hand. This mechanism is in almost every case a siphon which is put into action when the water level reaches a certain height, and which discharges rapidly until the water falls to a point when air is admitted to the inside of the siphon pipe, thereby interrupting the flow.

Fig. 16.—Flap Valve with Metallic Seat Attached.

There is on the market a dosing apparatus which does not involve a siphon, and which is shown in Fig. [18]. This is made by the Ansonia Manufacturing Company, 30 Church Street, New York City, and its operation may be described as follows: It consists of two floats connected by means of a chain which passes over a wheel supported in the upper part of the chamber. As the water in the chamber rises, the left-hand float shown in the drawing rises and the right-hand float falls, thereby communicating a rotary motion to the wheel. A projection on this wheel at a certain point when the left-hand valve has reached the desired height communicates with an inside portion of the wheel, to which a chain connected with the valve is attached. Thus the valve is opened at the right height, and remains open until the water has fallen to the bottom of the chamber. Then the left-hand float falls, and the apparatus is ready to repeat the operation. This apparatus, for a small installation, will probably cost, set up in place, about $15.

Fig. 17.—Flap Valve with Loose-link Hinges.

Fig. [19] shows the simplest form of siphon arranged to discharge water from a tank. It will be noticed that it consists of an inverted bent pipe, one leg being longer than the other, and extending into a pool of water formed in the end of the discharge pipe. When the water level in the tank reaches the bent portion of the siphon pipe, the water begins to flow out, and will continue to flow until air is drawn in at the lower end of the short leg. This stops the flow and the tank begins to fill again.

Fig. [20] shows another method of working the siphon and insuring its rapid initial action. This is known as the Van Vranken flush tank, and the feature of this arrangement is the movable bucket, which in one position seals the lower end of the longer leg. Then, however, the siphon begins to act, and the bucket, which is hung on trunnions, is disturbed and its contained water is dumped out. This allows the escape of the water in the longer leg and insures a vigorous starting up of the siphon into action.