Posted Thu Feb 17, 2005, 8:21pm Subject: Re: HX/E-61 Temperature Control
Some quick math shows that, for 1/8" copper tubing, 24.5ft would be required to produce a 56ml internal volume. Some more quick math estimations tells me that two tight spirals, about 5 inches across, back to back, would do the job. 24ft of heat rope at, say, 4W/ft only gives me 100W, which may or may not be sufficient... Let me see what I can find in heat rope...
djmcmath Senior Member Joined: 8 May 2004 Posts: 138 Location: Seattle, WA Expertise: I love coffee
Espresso: Gaggia Espreso Grinder: Solis Maestro Plus
Posted Thu Feb 17, 2005, 10:25pm Subject: Re: HX/E-61 Temperature Control
Or, given 30 seconds between shots, that ought to be enough to gain 10 degrees (though I bet it wouldn't be stable at 10.00 above wherever it started...). Optimally, I should only need to change about 2C, which ought to be easy, then. :) Whee!
This weekend is already shot. The first time I'll have even a first chance to actually pull apart the machine, take measurements, etc. will be about Monday. (sigh) I'll report back when I have something.
jonr Senior Member Joined: 25 Jun 2013 Posts: 224 Location: USA Expertise: I like coffee
Posted Thu Jul 18, 2013, 5:50pm Subject: Re: HX/E-61 Temperature Control
Old topic, but I think that it's correct. Even a manually adjusted mixing valve, mixing together ~70F water from the tank and 250F water from the boiler should result in a steady 200F with fewer variables to cause problems than the typical HX machine&. And you could get some control over temperature profile.
One issue I see it that the boiler would be exposed to the full 9 bars of brew pressure instead of just the 1 bar that it currently sees. I don't think I want to assume that mine will stand up to this.
& - as I see it, a HX machine has initial HX temp, flush time/volume, delay to start of brew, flow rate, tank water temperature and ambient air temps. All of these have to be quite consistent to get the right temp out of a HX machine. Even boiler temp changes with pstat hysteresis and barometric pressure.
LanceMagnum Junior Member Joined: 29 Sep 2013 Posts: 2 Location: Hamilton, MA Expertise: Just starting
Posted Sun Sep 29, 2013, 7:06am Subject: Re: HX/E-61 Temperature Control
I'm new to this myself, but I had a similar thought. A precise mixing valve seems to me to be a nice way to handle this. Keep the boiler at steam temp and run the hot & cold to a microprocessor controlled mixing valve. Could also add a diverter after the mixer to flow some through the grouphead to keep it at temp then divert to the showerhead when given the go signal.
The thing that strikes me about this arrangement is the temp profile. We know that temp control is important for a good shot. But what if a dynamic temp profile is better? What if some grinds like a 'ramp' in temp to extract the best organics? What if another grind likes to be hit at 198 and 205 but doesn't like 202? A mixing valve allows this possibility. Could use lots of feedback loops with extraction temp, grouphead temp, ambient temp, etc. along with heuristics so actual extraction temp profile closely matches desired one.
Add bluetooth or wifi, network in your grinder, and you can share grind settings & temp profiles with your friends.
calblacksmith Moderator Joined: 25 Nov 2007 Posts: 6,834 Location: Riverside, Ca, U.S.A. Expertise: I live coffee
Espresso: ECM Veneziano A1 Grinder: Many different commercial Vac Pot: 40s era Silex Drip: Milita, Bunn&Curtis... Roaster: Cast iron pan, gas burner
Posted Sun Sep 29, 2013, 8:10am Subject: Re: HX/E-61 Temperature Control
I tried to just skim but to understand what the thoughts were, that was out. There is nothing new about what was discussed here when it was posted and nothing new now. The OP is a good candidate for a DB machine. There is no need to jump through these hoops to redesign a machine into what has been made.
A HX machine is pretty darn consistent after the cooling flush sequence but they want to avoid a flush which can not be done, all machines require a cleaning flush an:-) d while HX require a cooling flush, most DB require a warming flush.
Honestly a deg or two will not make a difference in taste that nearly anyone will taste, let alone a half deg. Tech has caused the problem of if we can see a difference in numbers, it matters when for nearly everyone, it does not. If you want a PID controlled DB, thats fine, buy one!
There is not a pressing need to go through all this trouble,.... Unless you need a project to work on and then, go for it but remember, the solution to this "problem" has already been found . to alter the HX as discussed above only turns it into a SBDU with PID. :-)
In real life, my name is Wayne P.
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