Waterworks

My title "Waterworks" could refer to a municipal division or to an older man's medical condition, but in this instance I am talking about my inherent interest in the flow of water between different levels. At the risk of loosing my anonymity I share two photos to prove my early interest:  

Now I am "grown up" I have the following recent photographic evidence of my continued fascination: the dog expressed surprising interest when the dam was breached. Indeed my definition of a satisfactory seaside is one with sand that is good for building and a water course.

Somewhere in between and closer in period to the second of these four pictures I remember an enjoyable day emptying my father's garden water storage tank and using considerable amounts of mains water via a hose pipe.  Regrettably no one was there with a camera.  The location was a hopefully unused vegetable bed in my parents garden.  I discovered, invented if you will, the venturi pump.  In my life I have invented several novel machines, most of which I discovered later had already been invented.  More of that in a later post maybe.  In this instance I discovered that I could lift water from a large lower reservoir (filled from the tank) to a higher reservoir by directing the hose jet along an interconnecting water channel.  I managed a few inches of lift and was exhilarated.

The venturi pump is an amazing invention. It has no moving parts (apart from the water itself). Correctly engineered it is strong enough to lift water from a reasonably deep well - where the advantage is that the mechanical parts can be at ground level.  Because it has no moving parts it can be used to pump stones, sand or sludge out of a sump.

The diagram below shows the principle.  The motive force is provided by high pressure water injected at (1) through the nozzle (2). The venturi effect occurs at the constriction (5).  You can check out http://en.wikipedia.org/wiki/Venturi_effect - the theory says the pressure at the constriction here will be lower than at (3) and thus suction is created.  Or is it?  Is it the constriction at (2) that does the job? - because we want the pressure at the inlet (3) to be low, not at (5).  You will find the book explanations curiously hazy at this point..

Another wonderful hydraulic invention is the ram pump, more of this in a later post.