lino wrote:That also sure looks like the hard way to load the PF handle...

I totally missed that at first! Very funny. Wonder if the drawing was done by one of the folks in the ESI parts dept...

malachi wrote:...Wonder if the drawing was done by one of the folks in the ESI parts dept...

When I had a patent drawing done, the drawing conventions set forth by the patent office are still based on pen and ink illustrations done 100 years ago....it was so bizzare seeing a modern carbon fiber part rendered in that way.

Dan, would it be possible to hook up all this equipment to your Lever machine?

It would be really interesting to compare the ramp up of pressure to the other types of pumps.

Henry

Lino and I have discussed this possibility for his Peppina since it has all the requisite fittings:


From Has anyone ever PID'd a lever machine?

Measuring the ramp up pressure of a lever machine against a blank portafilter would only be mildly interesting (I would expect to see an initial pressure around the same as the boiler pressure, then nearly straight up to max pressure). Neither Steve nor I have volunteered to tap the grouphead our respective Olympia Cremina / Elektra Microcasa a Leva in the search of the truth, however he did offer a close approximation in Olympia Cremina 2002: The evolution of design using an ordinary bathroom scale:



Of course this trick wouldn't work for the Microcasa, but presumably one could guesstimate the pressure profile by measuring the brew pressure at the top and bottom of the spring's travel. As I recall Lino's mechanical calculation, the Microcasa's spring is capable of putting out around 6 bar and tapers off to around 4 bar. A lot less than I would have expected.

I've been using this as my at the group pressure reader. Not a cheap gauge, but worth it, as I 've measure some of the quality cafes around here and seen that the Marzocco gauges are reading higher than this devise. Which brings up another point. As we get more and more into pressure profiling, and studies, when can we do away with the "Bar" measurement? Or at least use it after reading in PSI first. 14.7 PSI per Bar, just a whole lot easier to read small amounts.

John

Jepy wrote: 14.7 PSI per Bar, just a whole lot easier to read small amounts.

nope. 14.508 psi/bar

barry wrote:nope. 14.508 psi/bar

Oops, sorry. I guess I should proof read, You get my point though, smaller increments....

Jepy wrote:Oops, sorry. I guess I should proof read, You get my point though, smaller increments....

Don't get your point. Who cares whether the measurement is 134 psi or 9.24 bar? Since everyone's been using "bar" for years, why change now?




(image of Mirage Idrocompresso)

It's not that I care what the numbers are 134 Vs 9.24(grey arrows), visually it's easier to read from the gauges I've found. I've been profiling my pressure for a while now, and seen how different coffees sweet spots can differ if only slightly. For example(subjective of course)Hairbender, pre-infusion 19 psi top pressure of 127psi Vs. Lighthouse Roasters Espresso blend pre-infusion again at 19psi, but tops out at 122. Both of these also have a ramp down pressure.

The pictured gauges are of similar pressure ranges, all marks should be roughly the same. What would you rather be reading from? I've cataloged quite a bit of data on different profiles for different blends, and wouldn't go back to bar myself. Next I'll be using the computer to data log, but still like to have the analog visual of my gauges.

John

I just finished installing a (wet) pressure gauge on the Silvia with a few loops of copper tubing to reduce the line pressure variations and provide some thermal isolation for the gauge. It hit me that, except for the thermal isolation and protection of the gauge, maybe I should have installed the copper coil just downstream of the pump, before the boiler, so as to provide a damping effect to the complete brew apparatus, not just the gauge.

Would such a coil, or perhaps a water-hammer type damper, provide a steadier pressure rampup and brewing pressure profile?