The Hydraulic Ram: Pumping Water Uphill

By Sam Moore
Published on September 6, 2012
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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.
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.
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).
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.
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.
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.
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.
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.

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