This is my first post in this community. I thought I would start by sharing.

https://bit.ly/LaPavoniCad - Hi-fidelity CAD model (CLICK THE LEFTMOST TAB ON THE BOTTOM, CALLED "PRODUCT")

https://bit.ly/LaPavoniCadGuide - Guide for using the CAD Model
https://bit.ly/LaPavoniCadPrintable - The simplified CAD model for 3D printing
https://bit.ly/LaPavoniCadAccessories - Accessories modeled in CAD for 3D printing

Welcome here.

Nice drawings and 3D model.
Have you printed it yourself and improved the original design?
How is it doing?

I created the model mainly to learn.
I have printed a 1/5 scale model (tiny thing in the pic)

VIDEO #1

An exploration of the CAD model of the La Pavoni Espresso Machines to see how they work.
Models of the Europiccola / Professional and Generations 2 / 3 / 4.

You need to water it a little.....

John Michael Hauck wrote: ... and here is a video walk-through of some of the CAD model.
http://www.youtube.com/watch?v=yPE-f8-SOzU

Very nice job! Thanks for doing it and for sharing. It does a great job of describing the different water/steam hydraulics of the gen 2 (sleeveless) vs gen 3/4 machines.

Some comments FWIW:

Some gen2 groupheads have only one inlet port drilled through, others have two.

I once measured the amount of water that was in the neck and head of a gen3 grouphead and came up with about 40ml when the piston is fully up. That indicates that most if not all of of the water supplied to a single pull shot comes from water that had been sitting in the group.

If you lift the lever on a gen 3/4 to flush a little water through the screen, you would expect the group to become filled with liquid water (no air or water vapor). Note that when the lever is down the area above the upper seal is at the same pressure as the boiler, but since the group is cooler than the boiler (which is at saturation temp/pressure) any vapor in there would condense to water.

When you lift the lever and the seal passes the inlet, your pressure at the inlet channel vents into the brew chamber, and for an instant that pressure drop would be expected to produce some flash boiled steam depending on how hot the water in the group is. A few ml of flash boiled water produces a very large volume of steam, and that initial steam may be critical in driving air out of the space between the piston and the not-yet-saturated coffee puck. If you still have compressible air in that space when starting the pull you expect a spongy pull and lower shot volume. (Here's an old thread discussing that: Operation of La Pavoni 1961-1973 and post 2000 groups). I don't know for fact, but have always thought that this was the reason they went to the trouble of putting that inlet channel in the plastic sleeve. (The gen 1 sleeves never had this channel - just had 3 simple inlet holes drilled through the brass sleeve.)

Some gen2 groupheads have only one inlet port drilled through, others have two.

That's interesting. It seems the number of nuanced changes made over the years could be daunting to document.
When modeling the Gen2, I noticed that the angle of the steam hole indicates it could (barely) be drilled through the neck in manufacturing.

I once measured the amount of water that was in the neck and head of a gen3 grouphead and came up with about 40ml when the piston is fully up. That indicates that most if not all of of the water supplied to a single pull shot comes from water that had been sitting in the group.

Curses, you just made me open up the CAD model to explore this some more! I calculated 35ml in head and neck with piston up just before the water inlet opens, and 48ml under the piston (and above the shower screen) when the piston is fully raised. That means 73% of the water for the shot is from the head and neck. I would never have guessed that much. It goes up to 83% if you count the 4.5ml of water in the copper pipe (which I wouldn't).

...any vapor in there would condense to water.

Good point! I did not think of that during the video. I wonder however, what happens to the air though?

...have always thought that this was the reason they went to the trouble of putting that inlet channel in the plastic sleeve

You are brilliant. I need to learn about flash boiled steam. I've wondered about the purpose of that channel. I've also wondered if it matters whether the channel faces forward or back toward the neck.

Your comments have taught me how much more about how this machine is designed. I thank you so very much. I'd like to continue this discussion. Are you a member of the Facebook group for owners of these lovely machines?

Thanks for sharing this..Nice Work!!!

John Michael Hauck wrote:Your comments have taught me how much more about how this machine is designed. I thank you so very much. I'd like to continue this discussion. Are you a member of the Facebook group for owners of these lovely machines?

It would not be inappropriate or off topic to discuss even the deepest tech right here. You can do anything you like but there is no rule or decorum driving the need to take deep tech discussion elsewhere.

-Peter