Now I see! Thanks for posting this Graham! It would be very interesting to see the brew pressure readings for these states too. I'm assuming this is with no coffee puck and guessing that maybe the last couple points are around 3-4 bar and the pressure is increasing at the more constricted positions?

All good! These readings were aimed at finding the "water debit" 30 second flow readings through the usable range of the paddle. This is around 220 degrees. The paddle is splined onto the needle valve stem, so I adjusted it by one spline to have the output range given.
All readings were taken with the brew water circuit pre-primed by a short bleed and water temp @ 92C. No puck, water output straight onto a calibrated scale.
The pump max pressure is adjusted to 10bar. At all paddle positions except 180 (parallel right) and 200 (full right) the pressure was 10bar. At these two high flow positions the pressure was 9.8bar.
Checking my brew record charts, I see a few shots averaging 1.5grams/second and even with extended p.i. (which makes a slower, lower average flow shot) your system will need to maintain 9-10bar at 45gms water debit or 90ml/minute.
As well as pump output, continuous operation cycle becomes an issue with long p.i. shots, as you have already noted, when using a vibration pump.

Tonefish wrote:One thing to keep in mind is that this project is largely a retrofit of ulka pump driven machines. Your S20 is too IIRC? Have you studied duty cycle ratings for them? JimS brought out a good point above regarding the potential to be running these pumps for 45 to 60 seconds.

Negative. I have a Procon 200LPH rotary in the S20. Very similar to Bianca. Which is another interesting point is that our pressure never budges (much) from the set brew pressure, even with the valve wide open. It is a valid concern regarding the extended brew cycles on a vibe pump. I don't think you would experience sudden pump failure; I would think it would more likely to cause accelerated wear and a reduced service life over the long term, but of course this is just a guess.

Tonefish wrote:True, although you can have a giant knob too. I'm just concerned that the more parts that need to be custom made, the more expensive this will be.

Understood. Even if said giant knob had a bit of a protrusion on it so you could learn how to control it by feel, rather than having to turn it back to some reference point and then count turns from there. Think of having to dial in your grinder every time from the zero point vs having a known reference point... but I suppose a dash mark on the knob and you're good!

Looking forward to seeing your progress!

- Jake

Sketches off to the valve manufacturer. I first tried to fit one of their valves into the mushroom cap but it needed to be a bit lower so the proposition is a custom made valve body or possibly a longer needle. This manufacturer does custom valves so I expect it to be just a matter of cost. We'll see!

I'd be interested. I also have a Quick Mill; mine is a QM67.

Sounds like this would be another good one for this kit.

Valve maker agrees that this is doable. Now we'll get into the details......

The valve "Wizard" should have everything he needs and a concept back from them should be shared soon!

I've provided a model of the concept and interface, relayed features necessary for this valve to replace the mushroom cap, and conveyed design goals. The main man is happy and he'll be turning it over to his designer/modeller tomorrow. He's asking a lot of questions about what we're doing and why, and seems to really be getting into it, which is always a really good thing! They're pretty busy (working tomorrow), so I don't know how long things will take but the progress has been very good and I get the feeling this will be worth the wait.

Incidentally, the only modification required for this kit is to trim your gicleur screen height roughly in half (but wait for your individual fit-up) . It could have been a pure drop-in replacement but I felt that the further the valve is from the gicleur the more likely concentricity with the gicleur could become an issue, so I thought it worth the screen trim to get that much lower. It doesn't compromise the screen flow area much since abut half the screen sits against the inner wall of the cap and the majority if the flow is likely from below the bottom of the cap threads anyway. So get an extra screen to cut and hang onto your old mushroom cap, and the whole mod will be fully reversible ... if you have that concern.

I'm more focused on function for now, so I haven't worried about the paddle versus knob, but I did find out that the knob attaches via a set screw onto a flat on the needle protrusion above the bonnet packing. This is more amenable to putting markings on the knob for location, than it is to making small angular adjustments of the paddle on the shaft such as with a splined tip and a screw into the shaft from the top. I really don't want to be too needy and turn off this maker who is willing to work with us, so those attempts may have to be pushed down the road. They also offer some variety of knobs including anodized aluminum, labels/names, and marking, but again, I'm more focused on getting the function going and ya'll can make it pretty later. Cheers!

Any plans for Profitec models?

If it's got an E61 group, chances are excellent. All it takes is an M16 x 1.5 mushroom cap thread and the distance from the cap seal to the gicleur of between ~0.55" and ~0.95".

EDIT: Looks like on the Pro 600 they eliminated the mushroom cap with a combined nut/cap .... blasphemous bummer!

I have the 700 which has a standard E61. I'm not sure if there's anything proprietary about it. Do you need a specific measurement to the gicleur?

If so I'm sure I can measure it, its due for cleaning anyways.

If you've got the 700 with the mushroom cap instead of the combined nut/cap you should be fine. I went out to the Profitec site and noticed the new 700s are similar to the 600 where they combined the nut and cap fro their E61 groups on those models. I wouldn't be surprised if they move that way with the others although shortsighted that might be. I say this because I'm really hoping some of these E61s reincorporate the valve up there rather than removing features.

The distance from the top of the seal washer to the top of the gicleur would simply need to be somewhere between about 0.55" and 0.95". I would suggest that anyone, before buying this valve, be certain they know what they have under the cap regarding the simple brass gicleur with a very small hole in the center, and know their cap threads. IF not comfortable with determining the cap threads, a relatively inexpensive solution is to spend $5 on this cap (with free shipping) to use as a gauge. I bought this part when thinking about threading a valve into it, and I measured the threads as well as fit-up to the nut to know they are the standard M16 x 1.5 threads.