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.
This is a device for automatically raising water from a lower to a higher level, the only requirements within certain limits being that the ram shall be placed at a given distance from the spring or source of supply and at a lower level, depending upon the height to which the water is to be raised and the length of the pipe through which it is to be forced. The distance from the source or spring to the ram should be at least from 25 to 50 feet, in order to secure the required velocity for proper operation. A difference in level of 2 feet, or even less, is sufficient to operate the ram; but the greater the difference, the more powerful is its operation. For ordinary purposes, where the water is to be conveyed from 50 to 60 rods, about 1/10 to 1/14 of the total amount used can be raised and discharged at an elevation ten times as great as the fall from the spring to the ram.
In Fig. 4, A represents the source or spring, B the supply pipe, C a valve opening upward, D an air chamber, E a valve closing when raised, and F the discharge pipe. When the water in the pipe is at rest, the valve E drops by its own weight and allows the water to flow through it. As soon as a sufficient velocity is reached by the water, its momentum or force raises the valve against its seat and closes it. The water being thus suddenly arrested in its passage flows into the chamber D, where its sudden influx compresses the air in the top of the chamber, and this in turn forces the water upward through the discharge pipe F. As soon as the water in the pipe B becomes quiet, the valve E again opens and the operation is repeated. Bends in either the drive or discharge pipe should be avoided if possible. If elbows are necessary, the extra long turn pattern should be used in order to give as little resistance as possible. These machines are made of iron and brass. The valve and stem are of bronze, on account of its wearing qualities.