Banishing the noise - vibe to rotary conversion

[zaphod]

I have no complaints with my Expobar Lever. When drinks come out poorly I can only blame myself.

BUT

That doesn't mean I can't dial the machine for a better experience. Will the rotary improve my shots? I don't know. If anyone has a 1:1 comparison I'd like to hear it.

What I don't want to hear is the rattling vibe pump every AM for the refill cycle and during every shot. It interrupts whatever story's running on NPR and I'm not willing to wait while the puck sits and oxidizes in the machine.

So the task at hand is to plumb the machine for both input & drain and externalize the new pump. Any wisdom: lessons learned, etc. would be greatly appreciated. Meanwhile, I'll be acquiring and assembling. Photos forthcoming when I've got something to show.

[malachi]

I'm hoping to figure out a way to do a test of this.
It would take getting two identical machines - one with vibe and one with rotary.
I have a theory about the resulting differences in cup quality - but need to test first.

[another_jim]

I'm hoping to figure out a way to do a test of this.
It would take getting two identical machines - one with vibe and one with rotary.
I have a theory about the resulting differences in cup quality - but need to test first.

Been there, done that, with two Juniors adjusted to the same pressure and temperature. Ken the owner of the machines and I alternated pulling blind shots for the other; and neither of us could discern a systematic difference.

One thing worth noting: We used a PF manometer with no surge filtering -- these are supposedly useless for vibe pumps. When the vibe's OPV was shut; the manometer was unreadable, the needle a blur between 12 and 16 bar. But once the OPV was open enough to get the pressure down to 9 bar, there was no vibration on the meter -- the OPV was absorbing all the surges that were previously visible.

My guess is that there is zero difference in the pressure profile of the two pumps once they are up to pressure. On a small gicleur machine like the Junior, there was also no difference in the dwell time. On a fast ramp machine like the stock gicleur LMs you may catch a difference in dwell time.

[malachi]

i still want to do it.
i need to identify the cause of the lack of definition and clarity i'm getting in the shots from the home machines versus the Mistral. i don't know if it is inherent to an HX machine, a vibe pump, whatever...

[HB]

So the task at hand is to plumb the machine for both input & drain and externalize the new pump. Any wisdom: lessons learned, etc. would be greatly appreciated.

I outboarded Valentina's pump:



It's inelegant, but effective and inexpensive. An external rotary pump would be no more difficult to install and even quieter. Setting up a drain isn't hard if you're handy. Depending on when you bought your Expobar, you may need the taller feet to give adequate clearance for the drainline (1-1/2" is more than enough).

[zaphod]

Once the parts are all ready, I'll get to work. The one thing that I think is unusual is that I'm ready...anxious... to destroy the counter.

So I'll have a big 2" hole drilled for the drain. I'm thinking some sort of screened funnel shape below the drip tray with a standard plumbing "trap" that feeds into the kitchen sink's drainage.

Then for the pump, I'll build a sound isolated under-sink structure and run the tubes through another nasty hole in the counter. To be honest, I haven't peered under the heavy machine to see where I'll enter with the plumbing. Given that it's always on, I'll burn myself if I did ;^)

The questions/concerns that I have is
a) does a typical motor that runs the vibe pump use a similar amount of power? i.e. could I plug the contacts to the vibe pump into the motor and be done?

b) Assuming I spec the proper procon pump, will all the pressures be correct? There's an overflow bleed that goes into the drip tray. There is a pre-infusion cycle and ~5-7 seconds before the pressure builds (with a change in vibe sound & the first drops of espresso)... do I risk losing that or is that a function of the e61 internals?

c) The other half of the conversion is to hard plumb. Currently the water is pulled from a pressure neutral reservoir. When I hard plumb, I'll have the household pressure. Does a rotary pump give me the ability to resolve this difference? My intuition is yes. I understand a vibe pump = input pressure + vibe pump pressure. Meanwhile a rotary pump doesn't care about input pressure.

[HB]

a) Vibe pumps draw very little power, on the order of 52W. A rotary pump motor will draw a lot more than that. I would guess in the same ballpark as the motor on the Mazzer Mini, which is rated at 250W.

b) The Procon pump has a built-in pressure relief valve, no overflow valve is necessary (the Cimbali Junior has one, but it serves as a safety feature, not pressure regulation as with a vibe pump). A rotary has a much larger flow rate, so I would expect the group will pressurize more quickly. Your Expobar Lever has an expansion chamber and gicleur valve that should render the different "dwell time" (to use Jim's words) negligible.

c) A rotary pump adds pressure, so the inlet pressure does matter. I've used this fact to avoid fussing with the pump by regulating the (inlet) pressure regulator. The relationship is not 1-to-1 though because of the pressure relief valve doesn't derate linearly.

The first question you'll need to figure out is the power requirements of the pump motor and if the existing wiring can support it. I would be tempted to ask WLL for a conversion cost since they know the machine inside and out. Terry at espressoParts might also be willing to do it for you. I know he's enthusiastically offered to convert vibe pump Lyras to rotary pumps.

[HAL9000]

I'm thinking some sort of screened funnel shape below the drip tray with a standard plumbing "trap" that feeds into the kitchen sink's drainage.

I have never plumbed a machine myself but if you haven't done this already (I'm sorry I missed your post, I am new here), I would probably avoid adding a new trap. It is not necessary from a plumbing perspective if you plumb the waste line so that it can take advantage of the existing trap (like a dishwasher), and if you do that the flow from the sink basin should blast away any coffee grounds that make it to the trap. I am just thinking that a separate trap that is fed only by the relatively low flowing espresso machine will just provide a place for the grounds to accumulate to the point of clogging.

[Teme]

I'm hoping to figure out a way to do a test of this.
It would take getting two identical machines - one with vibe and one with rotary.
I have a theory about the resulting differences in cup quality - but need to test first.

i still want to do it.
i need to identify the cause of the lack of definition and clarity i'm getting in the shots from the home machines versus the Mistral. i don't know if it is inherent to an HX machine, a vibe pump, whatever...

Doesn't 1st Line carry the Fiorenzato Bricoletta in both vibe pump and rotary versions? And since you already have the rotary version, I would imagine it should not be too difficult to arrange such a test?

Just an idea.

Br,
Teme