PHOTO: Jesse Frost
Jesse Frost
April 27, 2016

Moving water has been a challenge for farmers since time immemorial. Water wants to flow downhill, and often, you need it to flow uphill. Your animals need it. Your garden needs it. Your family needs it. So for centuries, when people needed water uphill, they laboriously hauled it there. But in the late 1700s, a Frenchman named Joseph Montgolfier—improving upon a slightly earlier patent—placed a valve on the pump that made it self-acting and made the water able to move itself. Thus, the self-acting hydraulic ram pump was born.

This clever device doesn’t require electricity but uses the force of water to move the water, so as you can imagine, it was a wildly popular tool throughout the 1800s. Although it fell out of favor when steam and electric pumps were invented, it’s making a comeback among sustainable farmers. The pumps take little maintenance, have great longevity and can be highly efficient. In fact, in some ways, this device’s ability to move water without the help of any outside energy, day and night, might make it the closest we’ve come to a perpetual motion machine!

How Ram Pumps Work

To understand how the pump works, first picture water traveling freely down a pipe and out onto the ground. Now imagine that flow is stopped at full momentum by something called a waste valve. Stopping the water while it’s moving suddenly creates a lot of pressure—called a water hammer—and some of the water can then be forced into a very tight space.

In the case of the ram pump, that tight space is an airtight tank, which the water enters through a one-way opening called a check valve; it lets water in but not out. The airtight tank temporarily absorbs the impact of the water, but when it rebounds, the air forces the water into a small pipe on the other side. Then, every second or so, this process is repeated. Do this enough times, and the amount of pressure in the tank will push the accumulating water in the pipe great distances and heights.

Buy It Or Build It?

ram pump tank
Jesse Frost

The first step in deciding whether to build or buy a ram pump is to measure the flow of water from your source. Using some sort of pipe, allow the water to flow into a 5-gallon bucket or another bucket of known quantity. Then, time how fast it takes to fill up to figure out how many gallons per minute you are getting. Do this, if possible, at the driest point of the year.

Technically, a savvy enough person can construct a ram pump for just about any amount of water flow, especially with enough drop. But generally speaking, more precision is needed for a flow rate of less than 3 gallons per minute. If your flow rate measures that little, consider buying your ram pump or having someone help you construct it. Notably, the manual for the Davey brand says that if your source is a large spring or pond, you can assume the supply is adequate.

You will also need to know what kind of drop you are working with—preferably no less than an 18-inch fall from the water source to the pump. If you have a lot of flow, but no drop, that might mean you have to travel far down stream to get enough pressure for the pump to work. Or conversely, if you have no flow and a lot of drop, you may have to set up a large reservoir at the source.

Installing Your Ram Pump

Keep weather, erosion and patience in mind when installing a ram pump. You’ll need to make sure the ram pump and pipes can be fully drained before deep freezes or are contained in a weatherproof building. (This can be a concrete tank below the freeze line, but it must be safe from freezing temperatures.) If the water inside the system freezes, it could ruin your pump. To help, make sure you have release valves against the pump on the drive pipe and the delivery pipe, if possible.

Because ram pumps are often located near water, you should also make sure the pump is safe from floods and other severe weather events; you don’t want your hard work washing away. Tie it down to rocks and trees, if need be, and keep in mind, a pump won’t work below water.

Because the ram pump is losing 80 percent or more of the water it uses onto the ground around the pump, enlist gravel and solid rocks to help stabilize the pump if on a slope so it doesn’t erode the ground, or so the pump itself does not slide downhill. Also, this is why the ram is not a good pump in conjunction with city water; it’s very wasteful in that sense.

Lastly, you have to have patience. There is a lot of nuance involved with installing a ram pump, so getting it right can be frustrating. Keep in mind that it might not work perfectly right away. Get a good manual, follow the instructions and consider having a friend experienced at plumbing or engineering help you.

How To Use Your Pump

A ram pump is best utilized in conjunction with a large holding tank, so when it’s unable to run—in freezing temperatures or in droughts—the tank can still be full of water. The pump fills the tank slowly, and the tank, positioned at the highest point on the farm, can then gravity feed water to wherever you need it. This water can then be used for irrigation, for watering livestock and, if you have a good, clean spring, for drinking. You’ll need to consider the height of the tank which will determine the pressure. So if you’re hoping to irrigate through sprinklers, for instance, you’ll need a fair bit of water pressure, and thus a large enough pipe and a lot of drop from the tank.

This article originally ran in the March/April 2016 issue of Hobby Farms.

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