This section is from the book "The Principles And Practice Of Modern House-Construction", by G. Lister Sutcliffe. Also available from Amazon: How Your House Works: A Visual Guide to Understanding & Maintaining Your Home.
Fig. 296 - Joint between Earthenware Outgo of Closet and Lead Branch of Soil pipe,as required by the London County Council.
Fig. 297 - Doulton's "Mettalo-ceramic",Joint between Earthenware and Lead.
Fig. 298 - Flange Joint between Earthenware and Lead, with Clips and Screws. CONNECTIONS OF CLOSETS TO PIPES.
Fig. 299. - Flange Joint - screwed to Floor.
Fig. 300.-Freeman's Screw Connection between Earthenware and Lead.
In all forms of wash-down closets where the trap is of the same material aa the basin, the form of the trap is necessarily that of the ordinary so-called syphon or round-pipe trap. As no trap is so easily cleansed, so is no trap more readily unsealed or syphoned out; and it is frequently necessary to provide against such an occurrence. The syphonage or unsealing: of traps is caused by the distrurbance of of the atmospheric pressure on the water in the trap, by the Midden discharge of a volume of water either down the main pipe with which the trap is connected, or into the apparatus to which the trap belongs. It can only be obviated in the case of a round-pipe trap by fixing a ventilation-pipe to the trap itself on the side furthest from the closet, as shown at a in figs. 292 and 293, and B in Fig. 295. In the ease of a stack of two or more closets discharging into one soil-pipe, each trap should be ventilated into a vertical pipe, which should be carried up and connected to the ventilation-pipe of the soilpipe above the highest w.c, as shown in Plate X.
Fig. 301 - Hellyer's Joint with Brass Thimble and Elastic Cement.
Fig. 302. - Humphereon's Joint.
In cases where lead traps are used, the Anti-D trap (Fig. 303) will as a rule obviate the necessity for a trap-ventilation pipe. This trap was devised by Mr. Hellyer with a view to prevent syphonage by allowing space for expansion, and under very severe tests has proved equal to the task. It is-well, however,not to depend too implicitly on the trap, but to make assurance doubly sure by providing the anti-syphonage pipe.
The flushing arrangements for closet-basins have been described with each class of apparatus, but it may be well to emphasize one or two special points. No closet of the "wash-down" type can be admitted as satisfactory, unless it has an adequate flushing rim. It is absolutely essential to the cleanliness of this kind of basin that the aides of the basin should be washed down at even flush.
Fig. 303 - Section of Anti-D trap.
It is also necessary, though perhaps not so vitally essential, to the valve-closet To the latter class of closets, what is called an "after-flush is most essential. Wherever the quantity of water used at each discharge of the closet is restricted by local regulations made in virtue of legal powers, a part of the water used for flushing should be retained, and only admitted to the basin after the valve is shut down. This is called the after-flush, and is required in order that the whole of the water allowed for flushing shall not be sent out of the basin, and the latter left dry.
In most places where a public or municipal water-supply exists, the quantity of water to be used at each discharge of the contents of a water-closet is restricted by by-law or regulation. This restriction is necessary in order to control the consumption of water, and prevent waste; but it cannot be denied that it may. and under some circumstances does, become very prejudicial to health. It is obviously right and proper that waste should be prevented, but to fix a hard-and-fast limit to the quantity of water to be used at each discharge of a closet, without reference to the position of the closet in regard to the drain, or to that of the drain in regard to the sewer, is absurd. We must, however, take the law as we find it, and do the best that can be done under existing circumstance The regulations vary in different localities, but the variation is so slight that it may be taken that the great majority of local authorities (including all the Water Companies of London) have fixed the limit of water to be used at each discharge at a maximum of two gallons. Now it may be admitted at the outset that, given a basin and trap of perfect form, and a flushing pipe of sufficient size fixed with accuracy, a flush of two gallons is under ordinary circumstam sufficient to clear out the basin and trap, and leave clean water for the next user. Experience, however, proves that the two-gallon maximum of the authorities should really be a minimum, and that in many cases a larger quantity i-required.
Whatever the quantity of water may be, it should be delivered in full and automatically; that is to say, the total quantity should be discharged into the basin at every pull of the handle, without it being within the power of the person using the closet to restrict the amount. Many inferior kinds of flushing cisterns, or "water-waste preventers" as they are more properly called, only discharge their full contents if the handle or pull is kept down until the flow of water ceases. This form of flushing cistern is much in favour with Water Companies, whose sympathies are, naturally enough, on the side of economy of water, and not in any way concerned with the sanitary side of the question. It is of course very necessary and desirable that water should not be recklessly wasted; but it is of far greater importance to the health of the community that sufficient water should be available for efficient Hushing.