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Kamis, 31 Maret 2011

Air, true or April Fool?

/ On : 21.17/ Thank you for visiting my small blog here. If you wanted to discuss or have the question around this article, please contact me e-mail at mozabani@yahoo.com

Since today is April Fools Day Air, here's a couple of trick questions to test and entertain you:

A small shrimp-like animal has a 'hammer'. It uses this hammer to break the shells of the crustaceans it eats. But the hammer does not exert enough force to break the shell on its own. So it creates a small air bubble on the end of its hammer. When the hammer hits the crustacean's shell this air bubble implodes and breaks the shell.

True or April Fool?

Leonardo da Vinci, the genius painter, sculptor, scientist and inventor urged his fellow scientists to "go straight to nature" in the search for knowledge and understanding.

Taking Leonardo's advice, if you wish to understand why cavitation eats away the innards of hydraulic components, look no further than the cavitating shrimp. If a tiny shrimp can use an imploding gas bubble to destroy the otherwise impenetrable defenses of its prey, it's little wonder gas bubbles which implode under high pressure in a hydraulic system can erode case-hardened steel and even softer yellow metals.

The cavitating shrimp is TRUE. As seen on the Discovery Channel.

The cylinder in the circuit shown below is drifting. In an effort to isolate the problem, the technician has installed ball valves 1 and 2. When both these ball valves are closed, the cylinder stops drifting. This proves to the technician that the cylinder's piston seal is not leaking and therefore he should replace the directional control valve.

True or April Fool?

This conclusion assumes if the piston seal was leaking, the piston rod would continue to drift with the ball valves closed. But with ball valves 1 and 2 closed, the cylinder's piston seal could be missing completely and the cylinder would still NOT drift. So it is wrong to conclude the piston seal is not leaking.

The technician is an APRIL FOOL.

To understand why, watch this 8-minute video

Yours for better hydraulics knowledge,

Brendan Casey