DIY
SCIENCE
Hydraulic Ram Pump
Clever invention pumps water uphill with more water.
By Matthew Gryczan
HOT-AIR BALLOON CO-INVENTOR
Joseph-Michel Montgolfier also invented an
ingenious device that pumps water uphill
with no external power source. Called the
self-actuating hydraulic ram, this device is
being rediscovered by engineers and social
advocates as a simple and sustainable way
to distribute water in developing nations.
The secret behind this pump is the “water
hammer” — the pressure surge that results
when flowing water is halted suddenly.
Gregory Hayes
The ram forks the water into 2 directions.
Most flows out through a waste valve, causing
it to slam shut. The resulting pressure spike
pushes some water through a check valve on
the other fork, and into the outlet pipe. The
check valve prevents this pressurized water
from backing up, so the water is forced uphill
through the outlet pipe. The pressure spike
also travels back up the inlet pipe and equalizes the pressure there, which reopens the
waste valve and restarts the cycle (Figure A,
following page).
1. Make the waste valve.
For the waste valve, I used a winemaker’s
bottle filler; these are rigid wands that let
liquid flow through when you stand their
weight on a valve pin at the bottom.
Tape the bottle filler pin in its down/closed
position, then drill a 1" perpendicular hole
through the black valve fitting, centered ½"
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