http://www.fluidotech.it/Pages/gear_pum ... eries.aspx

These new gear pumps are extremely small compared to the typical rotary pump. I think it would be the best option for a swap with a vibe pump machine. A lot of folks don't think there is much improvement in switching pumps, but I can think of one PRESSURE PROFILING. Why every rotary pump machine doesn't have a knob to control pressure is beyond me (or for that matter vibe pumps with "wave cutting" programs to reduce pressure like the BDB preinfusion or the ZPM). I'd be looking to swap this pump and a nice little controller into a few certain pump machines that are popular right now. It seems like this would be the bees knees.

Imagine a CC1/silvia/BDB with a pressure profiling DC pump. The question is - what's the price, and how can you wire it to play with the onboard controls?

This MGFR configuration (200 and 300 are similar, the difference is on the seals) is very neat and expensive. Some of us already is playing with it. I did some testing and manual control, but Jacob did an Arduino control for his GS/3 and another member is playing with his GS/3 and manual control too.

I'm lazy to link them here but you can search for MGFR and find some posts. I did some dumb videos of the pump:
The price is around $500 and the pump is powered by a 24VDC source and controlled by a 0-5V signal. It has an output signal as a tacometer (so you know the actual speed of the pump).

It doesn't have a check valve (so you'll have to add one as the vibe pumps have it internally) and it's a good idea to have a expansion valve to limit maximum pressure as a safety feature, after the pump.

Márcio.

The thread about them is here, smaller pumps like the MGFR & MGCF are near the end.

I dont think profiling would benefit every rotary pump machine, especially HX which the majority are, I tried it and slowing down the flow to get the pressure reductions lead to burnt shots most of the time. It might not be the case with all HX designs but I wouldnt willingly submit my tastebuds to more testing.

I have been quoted 244euros for the MGCF picked up from an italian distributor, other parts necessary to be up and running with it in a silvia total about 70.

Also came across this a few weeks ago http://josh.to/crema, hes designed an arduino addon board with PID and vibe pump wave cutting. AFAIK he doesnt plan to sell them but maybe if he's bombarded with interest....

The slightly older, and slightly larger, MG204 pump/KAG motor combination, as used in the stada ep, seems a little easier to get hold of. I picked up one used on ebay for about £60, and there were a few around at the time. Who's your Italian distributor, I'd be interested in the new price of these? To drive it I use a £20 universal 24v dc laptop charger on which I've replaced the voltage select switch with a potentiometer.

Its for the MGCF11S = MG204 pump/KAG motor combination. They also quoted 164euro for the MG204 itself.

TEOREMA (info@teoremasrl.com)

I bought a couple from ebay for £60 too, approaching 3 months daily use without a hiccup

Excellent responses. I'm thinking of this as a replacement for vibe pumps on smaller machines (silvia/bdb), so the larger pump wouldn't work inside the casing. The 600$ price tag, however, makes the vibe pump wave chopping seem much more feasible.
The trouble with the machine market, as I see it, is too much automation. For instance, the CC1 and BDB would be a great candidate, but it has too much sophistication built in which prevents modification. This make the silvano/silvia look more attractive. Could you swap a rotary/gear pump and hook it up to the existing controls for a vibe pump in a BDB/CC1 with ease, or would this also require a total reworking of the code?

4000ft wrote:I dont think profiling would benefit every rotary pump machine, especially HX which the majority are, I tried it and slowing down the flow to get the pressure reductions lead to burnt shots most of the time.

You have to lower the temperature to compensate for the longer contact time. I assume you can do that with an HX, but it will change your PID settings and possibly your flush dance.

I think there's general agreement that pressure profiling doesn't work all that well with darker roasts and typical comfort-food blends. It seems to be most applicable to light-roasted SOs, where the extra contact time helps to extract more from the coffee. This is consistent with other techniques that have been used to extract more from light-roasted SOs, such as increasing the temperature, down-dosing, etc.

bostonbuzz wrote:The trouble with the machine market, as I see it, is too much automation.

Why do you think that?

To my knowledge, the automated features in current machines don't preclude adding manual or automated pressure-profiling. Manual pressure profiling can be achieved without the fancy control code ever being aware of what you're doing. Automated pressure profiling can be achieved as well, though it might be a little tricky to find the right places to monitor the existing control signals (i.e., you need to know when the motor is running, when the brew solenoid open/closes, etc.)

Although it would be nice to monitor the low-voltage logic signals on the control boards of the newer machines, it may or may not be easy to do that, especially without a schematic or specs on component current limits. But at the end of the day, it's pretty easy to connect to the AC signals in any espresso machine with inexpensive chips like the MID400 that Josh uses (in an amazing coincidence, I came across that IC today in my search for just such a chip, and then read this thread and saw that Josh is using it!)

Also, for automated profiling, you have to add a pressure transducer if the machine doesn't have one you can tap.

The automation isn't a problem, the pumps are still 110/220v just disable the machines pre-infusion magic and hook up the 24v converter from the original pumps power.