Olympia Cremina monitored/controlled pressure profiling [video] - Page 2

August 27th, 2015, 9:31 am

Great

. Thanks for the link! I've been a bit unsure because of that old digital scale.

November 22nd, 2015, 4:42 pm

To much compromises with the Pressure-Profiling last time?

1. The piston rod was made of ordinary steel, because the SS-rod was simply to hard for our tools to drill through the whole lenght. We broke two borers and they got stuck inside the hole.

2. The Pressure gauge was a resonably priced one, which could not withstand high temps. That's why I used a cooling spiral between rod and gauge, which made the whole measuring to a nightmare and the machine ugly.

But I've found this machine half a mile away from the roastery. I don't know the exact name for the thing. Spark erosion maybe? One day later the hole was free through the whole lenght. Amazing.

Some adjustment with the CNC-Machine for the half pins:

Four days ago I've found the proper stainless steel heat resistant pressure gauge:

Today I could test with a small handicap (a broken right shoulder blade) and worked just fine. A small seal problem all it has.

https://youtu.be/U5g81JakM3M

#13: Post by **CoffeeBar** » November 22nd, 2015, 6:29 pm

PERFECT!

#14: Post by **day** » November 22nd, 2015, 6:46 pm

I thought my postal scale was excellent for pressure profiling. But you, sir, have really nailed it. If you get one for pavoni that your closest friends don't want let me know

For good measure I will now post a picture of my now outdated method:

http://www.amazon.com/WeighMax-W-4830-I ... B001AKV422

#15: Post by **CoffeeBar** » November 22nd, 2015, 10:47 pm

day wrote:I thought my postal scale was excellent for pressure profiling. But you, sir, have really nailed it. If you get one for pavoni that your closest friends don't want let me know

For good measure I will now post a picture of my now outdated method:

http://www.amazon.com/WeighMax-W-4830-I ... B001AKV422

<image>

+1

And hopefully naked-portfilter, could provide us this as a kit set for measuring our brew pressure in our machines( La Pavonic and Olympia Cremina )

November 23rd, 2015, 4:31 pm

A postal scale is a great tool. The simpler the better. It is maybe a bit more difficult tough than the pressure gauge tuning but you definitely won't have any sealing issues

.

#17: Post by **day** » November 24th, 2015, 7:53 pm

EDIT: I was originally thinking of 1bar from the boiler, stupidly, now I realize it would be super easy to get a nice one pretty cheap in the 200PSI range, specifically designed for up to 300F temps. Will update the links etc after I find some of the best options, now I just have to figure out how to get one of those pistons...

naked-portfilter wrote:A postal scale is a great tool. The simpler the better. It is maybe a bit more difficult tough than the pressure gauge tuning but you definitely won't have any sealing issues .

Tell me my friend, what you think of this. I am very excited to entertain the idea. A dual pressure and temperature gauge...

http://www.supplyhouse.com/Watts-012166 ... e-0-50-psi

(the picture is of the 0-200 psi but this one is actually 0-50 which should be servicable though I would prefer 0-30psi.)

Apparently they are called tridicator gauges.
Just started looking into them, would prefer a more robust sS wetted parts, I also have not gotten to research accuracy-as I understand it all pressure gauges are rated from a 68 degree reference-from Wika (the gauge manufacturers information, not wiki), and so even at pressure there is some notable devitation from true pressure. Thus, with our temperatures operating in the upper end of the temperature range it may be simply too inaccurate at a reasonable price point, but, still, it does look like a fantastic concept...

November 25th, 2015, 4:05 pm

day wrote:EDIT: I was originally thinking of 1bar from the boiler, stupidly, now I realize it would be super easy to get a nice one pretty cheap in the 200PSI range, specifically designed for up to 300F temps. Will update the links etc after I find some of the best options, now I just have to figure out how to get one of those pistons...

Tell me my friend, what you think of this. I am very excited to entertain the idea. A dual pressure and temperature gauge...

http://www.supplyhouse.com/Watts-012166 ... e-0-50-psi

(the picture is of the 0-200 psi but this one is actually 0-50 which should be servicable though I would prefer 0-30psi.)

Apparently they are called tridicator gauges.
Just started looking into them, would prefer a more robust sS wetted parts, I also have not gotten to research accuracy-as I understand it all pressure gauges are rated from a 68 degree reference-from Wika (the gauge manufacturers information, not wiki), and so even at pressure there is some notable devitation from true pressure. Thus, with our temperatures operating in the upper end of the temperature range it may be simply too inaccurate at a reasonable price point, but, still, it does look like a fantastic concept...

Great idea. I like it. My only problem with this gauge, that we should put the thermocouple below the piston to get proper readings. To measure the water in the stainless steel piston rod makes not much sense for me (except we know/can calculate the off set exactly). But here is surely a solution to this properly. We need very quick response time for the temperature readings without a battery. Is there a way to go? It should stay maintenancefree and as simple and as possible.

Cheers

Gábor

#19: Post by **day** » November 25th, 2015, 4:59 pm

If have been searching but the most accurate I have seen so far is +-3C, not really good enough. Many of them do come with an extension that, if thin enough, would bring it pretty low and close to the target. No idea what the reaponse time is though. Probably the best way would be a custom designed square shaped gauge with the temperature read out over the entire left top and bottom of accurate enough to maintain the improved scale detail. Not enough money for that myself but I will lol some more later

#20: Post by **jonr** » November 26th, 2015, 11:07 pm

When actually pulling, if you're watching and maintaining a steady flow or tail from the PF, you likely will pull hard at first and ease off toward the end.

My experience is similar. All I concentrate on is the rate that the lever moves, ie, flow profiling. If I wanted a readout, I'd put a scale under the cup.