Ram Pump

Imagine if there was a way to pump water without having to supply any external energy. No gas-powered pump, no solar pump, no manual effort etc. Sounds like an impossible dream doesn't it? Well, the Ram Pump doesn't violate any of the laws of Thermo Dynamics and in fact depends on the law of Conservation of Momentum to operate. So what the heck is it anyway? It's a pump. It requires a constant flow of water into it - with a head of at least 3 feet. For this input, you will get a constant supply of water pumped to a height of up to 30 feet at about 1/10th the flow rate of the input water source. They are reliable. My pump typically operates 24/7 for the entire summer. They require no outside power source other than a supply of water at least 3 feet above the pump. The water supply can be a spring, river, even a beaverdam can give you the 3 feet of head needed to drive the pump. They work 24/7 and are ideal where electric power is not available and a low-cost solution is needed. Ram pumps are an old though not-quite-ancient invention. Invented in Europe in the late 1700's, they were fairly popular until the widespread use of electricity and specifically electric pumps hampered their value-proposition considerably. In my case, I have a small artesian well that produces between 3 - 10 gallons per minute year round. Unfortunately, this spring is 30 or so feet down a ravine and thus at a lower elevation than the garden and trees I need to water. After some research, I discovered the Ram Pump. I pieced one together with various off-the-shelf plumbing parts (only one part requires moderate modification). I now have a pump which delivers about 500 gallons of water per day to a height of about 40 feet above the source. I store this water in a 1000 gallon tank and use battery-operated irrigation timers to drip irrigate several hundred trees and shrubs as well as the garden. It made a tough job easy.

How does it work? It's not easy to explain in words. Essentially, the water which is driving the pump is allowed to build up speed while spilling out of a special valve on the pump. Within a second, the flow is moving fast enough that it lifts the valve and effectively shuts off this exit. Now you have a moving column of water that has just been brought to a standstill. The kinetic energy of this moving water column is enough to overcome the higher static water pressure on the delivery side and so a little squirt of water makes it out the delivery pipe at a higher elevation. The entire column of water (the supply and delivery sides) is now at a standstill and soon realizes that it should be actually heading up the supply pipe because it has less head pressure than the delivery side of the pump. So, the entire water column starts moving towards the source when the check valve which seperates the supply and delivery sides closes behind him. Since he is still moving, this inertia creates a small suction on the waste valve which causes it to open. Now the water realizes that it shouldn't be heading uphill into the supply pipe - it should be heading downhill towards the open waste valve. The cycle now starts again. Relentlessly, ram pumps continuously cycle, each time sending a small pulse of water up the delivery pipe to a higher elevation. Because this is happening 24/7, even a small flow can add up. I get about 1.8 litres per minute out of my delivery pipe - which is about 500 gallons per day!!! Not bad for a very small investment in time and money!