21 Jan
2003
21 Jan
'03
12:35 p.m.
On Tue, 21 Jan 2003, J.C.Wren wrote:
Side relief holes actually increase the volume of
air, via a venturi
effect. You do get reduced air speed, but more volume. They're also a
safety feature of some kind, but damned if I've figure out how.
High enough pressure (>40 psi) air through a small enough diameter
nozzle can easily cut into soft flesh, and can rip ugly gashes in you
under the right circumstances. Hence, the side holes prevent the full
static pressure of the system from appearing at the tip, while, as you
have said, entraing more air, providing the same volume at lower presures.
And, while I respect and admire Chris for the Wild and Crazy guy he is,
I try to use the lowest press prossible when de-grunging something: higher
pressures and flows can do damage to Delicate Things, and at high
pressures the Grunge goes flying everywhere and precipitates down, like
Chernobyl Snow all over everything in the Shop.
Cheerz
John