This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
There is a great variety of water closets from which to choose, many operating upon the same principle but varying slightly in form and finish. The best are made of porcelain, the bowl and trap being in one piece without corners or crevices so that they are easily kept clean. The top of the bowl is provided with a wooden rim and cover. The general arrangement of seat and flushing tank is shown in Fig. 7. A section through the bowl is shown in Fig. 8. This type is known as a syphon closet, and those made on this principle are probably the most satisfactory of any in present use. They are made in different forms by various manufacturers but each involves the principle which gives it its name. Water stands in the bottom as shown, thus forming a seal against gases from the sewer.
COMBINED NEEDLE AND SHOWER BATH ARRANGED FOR HOT AND COLD WATER.
The Federal Company.
When the closet is flushed, water rushes down the pipe and fills the small chamber at the rear which discharges in a jet at the bottom as shown by the arrow. The syphon action thus set up draws the entire contents of the bowl over into the soil pipe. In the meantime a part of the water from the tank fills the hollow rim of the bowl and is discharged in a thin stream around the entire perimeter which thoroughly washes the inside of the bowl each time it is flushed. Fig. 9 shows a form called the "wash-out" closet. In this case the whole of the water is discharged through the flushing rim but with greater force at the rear which washes the contents of the upper bowl into the lower which overflows into the soil pipe. This is a good form of closet and is widely used. A similar form, but without the upper bowl is shown in Fig. 10. This is known as the "wash down" closet and operates in the manner already described. The water enters the bowl through the flushing rim and discharges its contents by overflowing into the soil pipe. This is a simple form of closet and easily kept clean.
One of the simplest closets is the "hopper" shown in Fig. 11. This consists of a plain bowl of porcelain or cast iron tapering to an outlet about 4" in diameter at the bottom. It is connected directly with the soil pipe as shown. The trap may be placed either above the floor or below as desired. They are provided with a flashing rim at the top similar to that already described. This type of closet is the cheapest but at the same time the least satisfactory of any of the different kinds shown.
It is sometimes desirable to place a closet in a location where there would be danger of freezing if the usual form of flushing tank was used. Fig. 12 shows an arrangement which may be used in a case of this kind. The valve and water connections are placed below the frost line and a pipe not shown in the cut is carried up to the rim of the bowl. When the rim is shut down the valve is opened by means of the chain attached to it and water flows through the bowl while in use. When released, the weight on the lever closes the valve and raises the wooden rim to its original position. Any water which remains in the flush pipe is drained to the soil pipe through a small drip pipe which is seen in the cut.