The Hydraulic Ram: Pumping Water Uphill

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Cattle drinking from a watering trough. Before stationary gas engines became widely available, the hydraulic ram pump offered an inexpensive, reliable source of water for livestock and irrigation.
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1. Water flows down the drive pipe (A) and escapes through the impulse valve (B). (This valve is variously called a waste valve, clack valve, escape valve, overflow valve or impulse valve.) As the water flows through the impulse valve, it builds enough pressure to suddenly close the valve.
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2. The water that has been flowing through the impulse valve has built up a large amount of momentum that must be dissipated. This so-called “water hammer” effect causes a sudden surge in pressure inside the pump body, forcing open the one-way delivery valve (also called the discharge valve) at (C).
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3. Moving water rushes through the delivery valve into the air chamber (D) and compresses the air that is trapped inside. When the water pressure in the pump body drops below that of the air chamber, the delivery valve (C) closes, trapping the water and compressed air inside the air chamber.
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5. The remaining movement of the water inside the pump recoils against the now-closed discharge valve, causing a slight vacuum inside the pump and allowing the impulse valve to reopen – causing the process to repeat.
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4. Pressurized water inside the air chamber (D) is forced out through the delivery pipe (E) to its destination.
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6. A typical hydraulic ram pump system. Water from the source flows through the drive pipe (A) into the ram pump at (B). The ram pump functions as described above and forces some of the water up the delivery pipe (C) to the destination at (D). (L) is the length of the drive pipe, (F) is the head or vertical fall from the water source to the ram pump, while (E) is the vertical distance the water must be lifted.

First, a riddle. What do a hydraulic ram and a hot air balloon have in common?

It all started in England in about 1772. In a 1775 letter to a Dr. Franklin (Ben?), a man named John Whitehurst wrote: “Dear Sir, Presuming the mode of raising water by its momentum may be new and useful to many individuals, induces me to send you the enclosed plan and description of a work, executed in the year 1772, in Oulton, in Cheshire, the feat of Philip Egerton, Esq., for the service of a brew house and other offices, and is found to answer effectually.”

The system wasn’t automatic, in that it required the opening of a tap to start the water flowing. However, the tap was located in a kitchen where “the consumption of water is very considerable (and) that water is frequently drawing from morning until night all the days of the year.”

On June 4, 1783, in an unrelated event in Paris, the Montgolfier brothers, Joseph and Jacques, sent up the world’s first hot air balloon. A few months later, the brothers demonstrated their balloon at a command performance for Louis XVI and Marie Antoinette at the Palace of Versailles. On that trip, the balloon carried a sheep, a rooster and a duck. Shortly thereafter, a science teacher and an army officer became the first human balloonists when they flew a distance of 5.5 miles over Paris.

Pumping water uphill

In about 1796, Joseph Montgolfier applied his inventive talents to the problem of pumping water. The Frenchman added a water-operated valve in place of Whitehurst’s manual tap. That made the device self-acting, and, as long as the water supply remained steady, the hydraulic ram was virtually a perpetual motion machine. Today, Montgolfier is credited with being the father of both manned flight and the hydraulic ram.

The fame of the simple pump that could push water uphill using only the energy of falling water spread, and several were imported into the U.S. In 1809, New Yorkers Joseph Cerneau and Stephen Hallett patented the first American water ram, but it wasn’t until the 1840s that use of the device began to spread. Hydraulic rams were mostly used to supply water to individual farms and homes, but there were larger installations. One firm claimed, in an 1852 ad, that the “Birkinbine Patent Improved Hydraulic Ram” had pumped 20,000 gallons of water a day to the town of Naples, N.Y. The Rife hydraulic engine was said to be capable of pumping water as much as 200 feet vertically in quantities as high as 50,000 gallons per day. Rife Hydraulic Engine Mfg. Co. remains in business today, making hydraulic ram pumps in Nanticoke, Pa.

Even though water ram pumps are easy and inexpensive to install and require little maintenance, they’re inefficient. In an 1866 experiment, where the head (or height of fall) of the input water was 8.8 feet, a ram was able to lift water 63.4 feet. However, 27.7 pounds of water were used per minute, with only 1.7 pounds raised to the reservoir. With so much water wasted in the ram, the devices fell out of favor when engine-powered and, later, electric pumps became popular. Today, however, with the growing interest in environmental concerns and the rising cost of energy, the ability to pump water uphill using only the energy of that water is again generating interest.

While chances of finding a good drinking water supply today are somewhat unlikely, the hydraulic ram pump can be used to pump potable water from a good flowing spring that has been tested for purity. There are, however, many uses for water from rivers, streams and ponds, such as watering gardens and lawns, filling a swimming pool or supplying cooling water to a heat pump. Even a small flow of 1 or 2 gallons per minute adds up to a lot of water in 24 hours. If the flow is sufficient, water for irrigation and livestock can be provided inexpensively and reliably. The unpressurized output of a water ram’s delivery pipe is especially useful in the drip irrigation systems so popular today.

How the hydraulic ram works

OK, so how the heck does a hydraulic ram work?

A hydraulic ram uses the energy of a large amount of water flowing a short distance downhill to force a small amount of that water to a much greater height. This phenomenon is possible because of a few basic laws of physics. First, a moving object resists being stopped. Second, water cannot be compressed. Third, air can be compressed. And fourth, gravity forces water to run downhill. Therefore, water moving downhill under the force of gravity, and contained within a pipe, will try to keep moving if the flow is suddenly stopped. This force is much greater than the actual weight of the water, and creates a “water hammer” effect at the ram, which is sufficient to force some of that water up a smaller pipe.

Because some of the air inside the chamber is mixed with the water being pushed out the delivery pipe, it needs to be replenished. (See diagrams in the Image Gallery for more details.) Many rams used a small sniff (or snifter valve) in the pump body that opened on the vacuum of the water recoil and drew in a little air. That air then entered the chamber the next time the delivery valve opened. Modern rams use a captive air supply (such as that provided by a diaphragm, a basketball bladder or an inner tube from a small tire) inside the chamber, thus eliminating the need for a sniff valve.

So, now that you know how to pump water without a power source, go ahead, turn on the tap and get yourself a glass of water. FC

Sam Moore grew up on a farm in western Pennsylvania. He now lives in Salem, Ohio, and collects antique tractors, implements and related items. Contact Sam by email at

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