Is it really that hard to design a quiet vibe pump system?

[AndyS]

...split from JetSteam Espresso Machine by moderator...

On the vibe, there is simply too much vibration and the ramekin has a tendency to dance across the drip tray during the shot

OK, I know I set the standard when it comes to espresso pump snobbery...but this post of yours, Ken, just cracks me up.

Shoutout to vibe pump machine users: why do you let the manufacturers get away with crap like this? You obsess about the aesthetics of your machines, you pimp and polish your chrome-plated mirror-finish groups, you wrap the grinder in a towel so as not to wake up the wife at 6am...then you turn on the pump. It sounds like a sadistic dentist performing a root canal with a jackhammer!

Is it really that hard to design a vibe pump system with some sound deadening? Chris Nachtrieb, Terry Z, are you listening?

[HB]

Is it really that hard to design a vibe pump system with some sound deadening?

My electric razor makes about the same noise as a vibe pump running; it's the vibration transmitted to the casing that makes all the racket. Assuming the assembly is good, you can minimize the noise by assuring all the components are securely attached and minimizing touch points. On the other hand, some manufacturers toss in the parts willy nilly and no amount of sound deading will help.

[Ken Fox]

OK, I know I set the standard when it comes to espresso pump snobbery...but this post of yours, Ken, just cracks me up.

Shoutout to vibe pump machine users: why do you let the manufacturers get away with crap like this? You obsess about the aesthetics of your machines, you pimp and polish your chrome-plated mirror-finish groups, you wrap the grinder in a towel so as not to wake up the wife at 6am...then you turn on the pump. It sounds like a sadistic dentist performing a root canal with a jackhammer!

Is it really that hard to design a vibe pump system with some sound deadening? Chris Nachtrieb, Terry Z, are you listening?

My vibe pump machine has been so heavily modified that I'm not sure I can even blame Cimbali on this. At the moment, there is a knockoff braided hose twice as long as from the factory, which goes out of the vibe pump into the rest of the plumbing, which itself has been modified. The OPV, which does not really function in the stock configuration, has been adjusted to work and has a silicone tube taking the excess water back to the pourover tank. All of the moving parts were replaced last year, and in the process the machine developed many leaks in the old copper fittings, which I tediously got rid of. The orientation of various pieces of copper is not exactly as it was before, but it works well.

I have done a few things to try to mitigate the noise and vibration, but nothing major, such as putting a rubber hose over the braided SS hose coming out of the pump. The reason why I have left everything in its current condition is that the changes unintentionally further damped out the pressure ramp up, as measured by a PF manometer. It takes a full 7 seconds to get up to 9 bar, and does it very very gradually, more than it did before. I consider this a plus, an accidental improvement, and am willing to put up with whatever occasional additional noise it produces. Considering that the machine operates maybe 1 week per month, and makes maybe 3-4 shots per day when it is working, the situation is not very distressing to me.

ken

[Ken Fox]

My electric razor makes about the same noise as a vibe pump running;

I have previously suggested to you to get rid of that old Remington and try out a Norelco.

ken

[espressme]

Just a thought...If the vibe pump depends upon the reaction of the innerd's along the axis of the outer part, the more firmly the pump is mounted, the better the performance and volume as there is no end to end vibration of the housing allowed to reduce the strength of each stroke of the piston. Perhaps adding a heavy mass to the pump and mounting the whole in rubber mounts would be a help. Keep it cool though!
http://jeromeetisabelle.free.fr/articles.php?lng=fr&pg=36
So, if so, I would think that any reduction of the radial and elongation stiffness of the plumbing from it would allow the pump to ramp up more slowly. Or, for instance; a Basket ball is very easy to pump till the last few strokes which take it to full pressure.
1¢
richard

[gtrman]

Has anyone ever measured the frequency of the vibe pumps? My guess is that its around 15-20Hz, but I will see if I can test that tomorrow. After finding the frequency of it, it would be fairly simple to design an isolation system. Practicality would depend on the physical size and empty space inside the machine. A rubber mount could be effective, but for total isolation (of the pump at least) it seems like some sort of cradle of springs would be needed.

Just thinking out loud here, unless someone else has already done this, I'll post my results if I can get any tomorrow in a new thread.

[AndyS]

Just a thought...If the vibe pump depends upon the reaction of the innerd's along the axis of the outer part, the more firmly the pump is mounted, the better the performance and volume

I don't understand; the "performance" and volume of the pump is already more than enough.

[AndyS]

Has anyone ever measured the frequency of the vibe pumps?

Depends on where you are. In N. America, 60 hz.

[gtrman]

That would be the frequency of the electricity right? Is it also the frequency of the piston in the pump?

[AndyS]

That would be the frequency of the electricity right? Is it also the frequency of the piston in the pump?

Yes. The pump uses a diode to produce pulsing DC. This DC repeatedly fires a piston against the resistance of a return spring.

I must confess that this info has been told to me by others; I have never dissected a vibe pump to verify it personally.

Someone who has, please chime in.

[terryz]

Is it really that hard to design a vibe pump system with some sound deadening? Chris Nachtrieb, Terry Z, are you listening?

I'm listening, but I can't hear you over this damn vibe pump! What was that again?

[AndyS]

I'm listening, but I can't hear you over this damn vibe pump! What was that again?

I rest my case.

[Ken Fox]

I rest my case.

I could see the point if it was a piece of equipment used in a cafe. I could see the point if it was going to be used in a house where it would be used at a time where it might awaken small children or a spouse, whose bedrooms might be nearby.

What I can't see is the concern over a little noise for perhaps 2 or 3 minutes a day, in a house, that will be heard mostly by those using it.

There are many aggravations involved in producing fine espresso in a domestic location, everything from roasting the beans to maintaining and fine tuning equipment. This concern over a little noise for a few minutes a day rates a 2 on a scale of 1-10, in my opinion.

ken

[gtrman]

Yes. The pump uses a diode to produce pulsing DC. This DC repeatedly fires a piston against the resistance of a return spring.

I must confess that this info has been told to me by others; I have never dissected a vibe pump to verify it personally.

Someone who has, please chime in.

Yes! (I know I asked the question in the first place...but...)
I just tested the pump on my Gaggia Espresso (55 watt Ulka) using a piezoelectric pickup attached to the orange pump housing and plugged into a strobe tuner advertised to be accurate to within .1 cents (a cent being 1 of 100 equal increments that separate 2 adjacent keys on a piano). The reading on my tuner teetered between B1 (61.74Hz) and Bb1 (58.27Hz) before finally settling on a flat B1. So in other words, the frequency of these pumps is in fact right at (or at least darn close to) 60Hz.

DISCLAIMER: I have not tested any of what follows in a real environment. All info is based solely on calculations, and practical applications of acoustic principles. By reading further, you agree that any harm, injury, loss, and/or damage and any negative effects at all are your own fault, and that I am basing all of this on a college level acoustics class. I have not tested any of this physically. I will when I get a chance. As always, electricity and water to not mix! Do all work with the machine powered down and unplugged, and make sure there are no areas shorting the circuit before powering back up.

60Hz being the Forcing Frequency in this system, the Natural Frequency of the mounting system should be no more than 6Hz, with a Static Deflection of .27 inches.

So: mount the pump on a set of springs (maybe a neoprene pad) which under the weight of the pump, compresses exactly .27'', and which the whole contraption will bounce up and down at a rate no more than 6Hz, and in theory, you have yourself complete vibration isolation.

I say in theory, because the piston in the pump moves from side to side, not up and down. And while it would not be impossible to do a horizontal mount, it would be much trickier to keep it stable. As long as you have your .27'' of static deflection and under 6Hz natural frequency--with compression springs--it could work. The vertical mounting WILL work, maybe not totally, but compared to how they are stock, it would be significant. A combination of the two would be ideal.

The other issue would be the vibration traveling through the plumbing, and into the boiler/grouphead. This would counteract the pump mount but shouldnt be too much unless the plumbing is rigid metal all the way from pump to group.

As far as transmission through the air, wrapping the pump in fiberglass insulation would help but that would depend on the amount of free space inside the machine.


Conclusion: A decent isolation system shouldn't be too hard for manufacturers to install in their machines, especially those with some extra space inside. I'm not too familiar on the plumbing paths and materials in the prosumer HX machines, but provided the lines arent totally metal tubing from pump to group, it would be significant isolation. For our DIYers, it would be a matter of going to a hardware store and testing out various springs and then figuring out how to mount it. Once I get some extra money for parts for experimentation, I will, and I'll post results unless someone else already has. The easy way to get rid of the noise though, is still to go rotary .

[HB]

The other issue would be the vibration traveling through the plumbing, and into the boiler/grouphead. This would counteract the pump mount but shouldnt be too much unless the plumbing is rigid metal all the way from pump to group.

I "outboarded" my espresso machine's vibratory pump:


Mounting board suspended from bottom of cabinet on rubber o-rings / eye holes

I was surprised how far the vibration would propagate along the water line. It literally would cause buzzing in the mounts 20 feet downstream from the pump. I blame most of this on the pipe material (John Guest LLDPE tubing); changing the hookup to braided stainless steel wrapped tubing with neoprene-padded strapping every 16 inches eliminated the downstream noise and reduced the pump's effective sound level to rotary pump levels.

[gtrman]

Woops, miscalculation on my part. My machine has just a few inches of silicone tubing.

[cafeIKE]

As far as transmission through the air, wrapping the pump in fiberglass insulation would help but that would depend on the amount of free space inside the machine.

Insulating the pump may reduce the duty cycle considerably as the pump would not dissipate the heat of pumping as quickly.

FWIW, judicious arrangement of the plumbing plus adding a couple of rubber strips have silenced my machine so it less noisy than the Macap M4.
1- add a foam strip along the face of the cup warmer tray.
2- add two rubber strips under the drip tray.
3- add a sink protector cut to fit the top of the cup tray to stop the cups vibrating.

[hbuchtel]

I was surprised how far the vibration would propagate along the water line. It literally would cause buzzing in the mounts 20 feet downstream from the pump.

20 feet!?!

Where did you put it, in another room?

Henry

[HB]

The 20 feet refers to the water hookup. The filter system is under the kitchen sink and the espresso machine is located on the opposite side of the room, thus I had to run a line under the house. Prior to the last changes I made, the pump vibration would propagate from the vibe pump and rattle the tubing / fittings of the filter system.

[Ken Fox]

The 20 feet refers to the water hookup. The filter system is under the kitchen sink and the espresso machine is located on the opposite side of the room, thus I had to run a line under the house. Prior to the last changes I made, the pump vibration would propagate from the vibe pump and rattle the tubing / fittings of the filter system.

Dan neglects to mention that transmitted vibrations caused the guest toilet to flush every time he choked the espresso machine.

ken