Rotary vs Vibratory

hedonist222

So rotary pumps put out about 10 to 12 ml/s whereas vibratory pumps put out 6 to 8 ml/s.

I understand pressure is a result of resistance (puck restricting flow of water).

So, how does a vibratory pump’s excess water affect pressure?

If a pump put out 1ml/s, it would take much longer for the puck to build up pressure.

Assuming all else equal (grind size and weight, force applied to tamp, temperature, pump maximum pressure).

Does a rotary pump bring the puck to maximum pressure (10 bar for example), faster than a vibratory?

Since more water flows and hence the puck builds up resistance faster.

Is this speed better?

MediumRoastSteam

hedonist222 Does a rotary pump bring the puck to maximum pressure (10 bar for example), faster than a vibratory?

Cuprajake Dont forget though, in an e61 machine the group has a natural pressure ramp up due to its mechanical nature

And that’s why there’s a pre-infusion chamber on E-61 machines. It’s a valve which opens, and a chamber fills when the pressure hits approx. 4 bar. It only lasts a couple of seconds. You can actually hear it. Initially used in a commercial environment with rotary pump machines, only relatively recently it has been featured in prosumer machines with vibe pumps.

From memory, with a rotary pump and E61 you’d generally start seeing first drips in approx. 4s, compared to approx. 8 to 10 seconds with a vibe pump.

DavecUK

hedonist222 Is this speed better?

No it’s not in all but a few situations and if they made a “silent” vibe pump there would be no need for Rotary pumps. It’s why I like the Lelit quiet pump, it’s really a huge amount better, and why I asked for a couple to fit in one of my non Lelit machines (Minimas) when I get the chance. It’s a job that will probably wait until I get a fault necessitating boiler removal, as I don’t fix what’s not broke.

So it’s easier to say when different types of pump benefit (and in the first 2 examples the pumps and motors are different).

Rotary

Multi Group Machine - when you require a large water flow rapidly in a commercial environment
Off boarded pump in a commercial machine
DC voltage controlled Rotary for pressure profiling machines
Small DC pump can be used as an expensive solution for filling a dual boiler lever group rapidly - To avoid 3 seconds of noise (or a little longer 5-7 seconds if refilling the service boiler after steaming.
AC Rotary Pump, fast filling levers groups, or for flow profiling but has to be rapidly pulsed on off….sub optimal solution to anything.

Gear Pump

Brushless gear pump, electronic impulse controlled (expensive, precise and very very accurate) For pressure profiling machines (very long life)
DC Gear Pump, can be voltage controlled high flow low pressure (much cheaper) can give very high flow rate. - Specifically, filling a large lever group rapidly in a dual boiler lever

Vibration pump

Superior in almost all situations that do not require high flow or electronic profiling….especially when using a solenoid operated E61, with or without a flow control paddle.
Noisy, unless it’s Lelits pump which is better although not “silent”.

The superiority of the vibration pump is:

Long life, often longer than a rotary in the prosumer machines
Pump curve/flow rate, much better suited for a prosumer machine
very small (a little marvel really)
Very cheap, usually easy to replace, is a single unit, not pump and motor, so no confusion over which bit has gone wrong or a leak in pump/seized bearings damaging the motor.

It’s like that old chestnut of the manufacturers being frightened of losing the little lever on the E61 group…they think you want that. They are frightened to remove it. They read negative comments on the internet about solenoid E61s by people who know nothing. A solenoid E61 has huge advantages over the version with a lever. I think almost every single pressure profiling machine that uses a lever E61 would benefit from swapping over to a solenoid E61..in fact not almost every one…every single one.

Lake_M

Basically, a vibe pump takes longer to build pressure above the puck than a rotary and has a much slower ramp time. A rotary can slam the pressure if no pre-infusion is applied, potentially fracturing the puck. That’s why pre-infusion is more important in rotary machines.

@DavecUK is an expert in these things and will give a far more technical explanation than me.

Cuprajake

Dont forget though, in an e61 machine the group has a natural pressure ramp up due to its mechanical nature.

Cuprajake

you can get restrictors though, im sure i read londiniums come with this if you drink dark coffee?

hedonist222

Any other effects, aside from pre flow.

Let’s say I’ve installed a flow control device and jettisoned the stock spring lieu of a firmer one.

And I’ve opened the flow restrictor to what each machine would output with a stock gicleur.

Which is what I’ve done.

Petre

DavecUK

That is super interesting indeed. Isn’t possible to use a vibration pump for pressure profiling? I always thought that would be the easiest to use by just electronically control the pulses. Not the case?

Boren

DavecUK Does a solenoid E61 include the same pre-infusion functionality of a lever-operated E61?

hedonist222

So rotary pumps put out about 10 to 12 ml/s whereas vibratory pumps put out 6 to 8 ml/s.

I understand pressure is a result of resistance (puck restricting flow of water).

So, how does a vibratory pump’s excess water affect pressure?

If a pump put out 1ml/s, it would take much longer for the puck to build up pressure.

Assuming all else equal (grind size and weight, force applied to tamp, temperature, pump maximum pressure).

Does a rotary pump bring the puck to maximum pressure (10 bar for example), faster than a vibratory?

Since more water flows and hence the puck builds up resistance faster.

Is this speed better

MediumRoastSteam

hedonist222 - That was your opening post, identical in fact. Are you not satisfied with the answers given?

LMSC

MediumRoastSteam Giphy - Season 2 Whatever GIF by Paramount+

hedonist222

By mistake end cannot seem to edit my post.

Thanks for the feedback guys.

Still wondering, though, if both pump types are rated to 12 bar and tuned to 12 bar but the rotary is able to supply more water. What does that mean or entail?
Specifically for someone coming from vibratory Appartamento to a rotary cinquantotto.

MediumRoastSteam

hedonist222 - You can only edit your post for the first 10 minutes after posting.

hedonist222 Specifically for someone coming from vibratory Appartamento to a rotary cinquantotto.

I’ll let those with more experience speak here. All I had to answer was answered already.

Cuprajake

In reality it makes next to no difference.

Your filling head space, in the pf

DavecUK

Petre That is super interesting indeed. Isn’t possible to use a vibration pump for pressure profiling? I always thought that would be the easiest to use by just electronically control the pulses. Not the case?

You can, there is a member @hornbyben https://coffeetime.freeflarum.com/d/256-poor-mans-decent-espresso-itoleva/27

You can add a flow control paddle to the machine.

I even tested a system of pressure and flow control with an electronic stop at the target weight.

Cuprajake

the decent is vibe too is it not

hornbyben

Cuprajake That was my understanding too. Vibe pumps are a bit noisy but you can definitely pressure profile with them.

DavecUK

Cuprajake It is yes…I forgot to mention it.

Cuprajake

id say yup