Hydraulic Ram Forces Water to Pump Itself
October 1948 Popular Science

October 1948 Popular Science [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Popular Science, published 1872-2021. All copyrights hereby acknowledged.

Last summer while at a community feast I was talking to a guy who recently moved from California - tired of the craziness there. He could be from the cast of Duck Dynasty, and has a strong independent spirit. He described a water pumping system he was considering installing which was self-powered and could lift the water from his pond up to a storage tank about 10 feet off the ground. There is no electrical power for running a pump near the pond. His herd of a couple dozen cows and a handful of sheep and pigs would be the beneficiaries. In my ignorance, I was thinking, dude, how do you expect water to pump itself up to a higher level; that violates conservation of energy. Fortunately, I kept my thoughts to myself. After reading this "Hydraulic Ram Forces Water to Pump Itself" article in a 1948 issue of Popular Science magazine, I realized it is exactly what he was describing! Commercially made hydraulic ram pumps are available for <$100, or you can easily build you own using instructions and videos on the Web. The downside is there is a lot of spilt water in the process. Also, the effectiveness of the pump depends on how far below the source level the pump is situated.

Hydraulic Ram Forces Water to Pump Itself

Here's a way you can have running water at minimum cost if there's a natural supply near your home.

Where conditions are suitable, a hydraulic ram is a very economical method of pumping water. The first cost is all you need to consider. Thereafter, a properly built ram will operate for years at no expense except for possible minor repairs.

A ram gives this economy by putting the water itself to work. Through a system of valves, it harnesses the energy imparted by falling water, forcing part of the flow to surge intermittently up a delivery pipe to an elevated storage tank.

If there's a spring, lake, pond, or stream in your vicinity to provide a constant flow, you have the first essential toward a steady supply of running water. Your source must be located so it can be piped to a lower level where the ram is located. There are two factors that determine how high the ram will raise the water. These are fall and slope, indicated above by A and B.

Fall is the vertical distance between the level of the headwater and the ram. Slope is the angle at which the water flows to the ram, but for convenience it's usually considered as the actual length of the drive pipe. For efficiency, the angle should not exceed 45 deg., and the length of the drive pipe should be somewhere between five and ten times the fall.

Here are some typical installations:

A small but efficient ram may easily be built at home. For the base, use a 2" by 4" cast-iron reducing sanitary cross. Saw off the small 4" end 2" below the threads. Face or dress the bell end flat and true.

Make the spring, strap, and clamp from 3/16" by 1 1/4" galvanized flat-bar stock. For the escape valve, assemble a 1/2" by 3" nipple, 1/2" galvanized waste nuts with the ears cut off, a 4" valve rubber, and a backing disk. A 1/4" rod threaded at each end holds the assembly together.

The flange is made from a blind flange for 6" pipe. Drill a 2 7/8" hole in the center and drill and tap two holes for the 5/16" cap screws that retain the spring. Carefully dress one side of the flange to provide a smooth valve seat.

Assemble the cross with a 2" by 10" nipple and a 2" conduit elbow. Tap the latter for 3/8" pipe about 2" below the threads at one end for the snifting valve.

Invert this assembly on the flange, with the bolts and clamp screws in place. Center the anchor bolts in the flange holes with tape and wire the washers in position. Stuff the interior of the cross with crumpled newspaper, topping off the stuffing with a small piece of chicken wire. Also wrap several layers of wire fencing loosely around the cross to reinforce the cement. Then build a wood form to enclose the cross.

The cement block must supply a solidity and mass that absorbs the ramming shocks of the water. Hence it should be carefully made. Thoroughly mix equal parts of sharp coarse plaster sand and lump-free cement. Wet slowly until jellylike and tamp into the mold. When the cement has set, knock off the form, remove the flange and the newspaper stuffing, and fill the interior with cement up to the lower level of the inside of the 2" pipes. Smooth this to reduce friction.

How Hydraulic Ram Acts

Invented a century and a half ago, the hydraulic ram harnesses the energy of moving water. As its name suggests, it rams, or pushes, part of the water to a higher level than the source.

To start, water is admitted to the supply pipe. At this point, the delivery valve A is closed and escape valve B is open. As the flow of water gains velocity, it snaps valve B shut.

This abruptly arrests the moving column of water. The resulting shock or pressure impulse forces the delivery valve A open and drives water into the air dome and into the delivery pipe. Acting like a piston, the water compresses the trapped air in the chamber.

Finally, the compressed air kicks the water back, closing valve A and giving the water another boost up the pipe.

Meanwhile, the pressure wave traveling back up the supply pipe reduces pressure on escape valve B, allowing it to open. Again there's a rush of water down the supply pipe and the same sequence of actions occurs. Each time the water is rammed farther up the delivery pipe.

In the usual hydraulic ram, the cycle repeats 25 to 100 times a minute.

The ram is now ready for installation. Lay a 2" supply pipe of a length equal to the height the water must be raised, keeping it straight and uniformly slanted. The fall should be as great as possible.

Cement the ram in position, connect the supply pipe, fit a gasket to the top of the cross, and bolt on the flange. Then assemble the escape valve and spring. Finally, attach the check valve and the capped 4" by 24" pipe nipple that functions as an air dome.

To start operation, open the gate valve, permitting the water to close the escape valve. Then push the escape valve open and allow the water pressure to close it. Repeat this action several times and the ram should pick up the cycle and operate automatically thereafter.

If you house the ram and use a tail pipe to carry away the waste water that flows out of the ram, be careful to locate the tail pipe high enough so it won't be submerged in times of flood. The overflow pipe from the supply tank may lead to a garden area, a stock tank, a pond, or back to the tailrace. The ram and piping must be buried below frost line or otherwise protected from freezing. - A. W. Kaufman, San Francisco.

Posted February 1, 2024