Introduction...

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david griner
Posts: 137
Joined: Thu Jul 10, 2008 6:39 pm
Location: peoria,az
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Re: Introduction...

Post by david griner »

Hello Stephan and welcome to the forum.
Thank you for taking the time and effort to develop the valve gear design program. Your work along with Mr. Dockstader, Mr. Aston and others are adding a great deal of insight into providing the ability to have really good steam distribution.
Respectfully,
Dave Griner
arizonamechanicalengineering.com
VGC
Posts: 111
Joined: Tue Sep 22, 2009 3:17 am
Location: Europe / earth - yet in freedom ;-)

Re: Introduction...

Post by VGC »

Hello,

thanks for your feedback.


@Pennsy fan:
To get it going, please take a look at the program specific comment:
http://www.chaski.org/homemachinist/vie ... =8&t=86510
"To use the program with some useful features, a user account can be ordered by email."

For more information about getting started, please look at the thread linked above.


@david griner:
Thank you ;-)
As some German speaking program users already said, there is some difference between earlier well known programs and mine: My program performs an optimization itself (at least in "Construct" Mode), meaning that it uses specific rules to combine some main dimensions into a well working geometry, whereas other parameters can be left "zero" or adjusted manually to simulate general deviation effects.
So the program does not primarily show results of manually optimized geometry parameters, but rather optimizes the several single geometry dimensions, based on some few gereral geometry parameters.

When I performed a reconstruction of a very badly designed valve gear that a model builder gave to me, and as I wanted to do it in "Construct" Mode to see all the explicit deviation parameters at once, it took me 2 hours to get it ready, with remaining dimension deviations of about 0.01mm.
When I design a new valve gear based on some few main dimensions, it takes me about 10 to 20 minutes until I can export the final DXF geometry (skeleton) file - if the recipient is ready to work with CAD and knows about dimensional layout of the valve piston (or if he has given me the valve piston event positions before).


But I also already had to give extended advice even to a manufacturer of small series of steam locomotive models, after reading his assumptions about valve gear behaviour - so it took me 6 hours (instead of one or two) just to be sure that he will understand the geometric results! ;-)

Greets
Stephan
VGC
Posts: 111
Joined: Tue Sep 22, 2009 3:17 am
Location: Europe / earth - yet in freedom ;-)

Re: Introduction...

Post by VGC »

Hello again,

here some video of another challenging steam-tec theme:

http://steamtec.lima-city.de/kesselspeisepumpe/video/

The text at the end of the video is

"Bei den Tests wurde aus verschiedenen Gründen eine Vorwärmer-Bauform mit besonders langer Wassersäule im Innern gewählt. Ohne Windkessel resultierte daraus ein erheblicher zusätzlicher Beschleunigungs-Gegendruck bei jedem Hubbeginn.
Mit Windkessel ist eine deutlich höhere Hubzahl zu erwarten.
Bei Tests mit Druckluft und kurzen Leitungen wurden trotz der engen Dampfquerschnitte des Prototyps bei 2 bar ca. 60 Doppelhübe pro Minute erreicht, bei 6 bar ca. 90 Doppelhübe."

This means

"At the tests, for various reasons a pre-heater design with extra long water column inside was used. Without pressure accumulators, this resulted in a considerable additional acceleration backpressure at each beginning of a stroke.
With pressure accumulators, a significantly higher number of strokes is to be expected.
In tests with compressed air and short pipes, despite the tight vapor cross-sections of the prototype, about 60 cycles per minute at 2 bar was achieved, or 90 double strokes at 6 bar."

(I hope, the correction of the translation is not too bad... ;-) )
Online program for valve gear design:

ValveGear Constructor [EN]

Image

With automatic pre-optimization, DXF export, etc.
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