PRV

2 years of research that involved:

_Dr. Ursula Becker,
_Alfredo Robbiati,
_Franco Balzarotti,
_Lucio del Piccolo,
_Petter Dahsltröm
and myself...

http://www.kaffeemaschine.de/
A coffee machine from the Brevetti Robbiati business in Milan.

This particular model with the pressure relief valve (PRV) has popped up in 3 countries until now (update 26 August 2012): Germany, Denmark and Sweden.
It is spring operated and uses a weight to seal the valve.

A pressure machine has to fit to different legal regulations.
For example:
In Germany, these are collected in the AD-Merkblatt:

http://www.ad-2000-online.de/

Here the first 2 pages:

Since the license to manufacture this coffee machine has been sold to a business in Solingen (Nordrhein-Westfalen / Germany)... one can wonder when will we see a coffee machine badged with "XXX Solingen Made in Germany".

Here some very nice shots from Petter Dahlström, Sweden: