Is it really that hard to design a quiet vibe pump system? - Page 2

[Randy G.]

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

ken

That's not really a problem, particularly since the dogs get fresh water with every choked shot. The real matter of concern is if flushing the toilet pulls a shot at the espresso machine!

As mentioned by cafeIKE, the noise I have dealt with was not caused by the pump directly but by other components of the machine vibrating. By simply using some foam weatherstripping under the top cover of Silvia I was able to dramatically drop the noise level. So much so that if I leave a tool or cup on the top of the machine during a shot it makes it sound like it's coming apart. I suppose that I will soon be doing much the same to my soon-to-arrive Domobar Super! Woohoooo!

[another_jim]

Hi Randy,

Hope this is a move, not just a sight seeing trip.

Domobar Whatever will become of the Silvia epic?

[JimG]

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 machines I am familiar with already use a very flexible neoprene mounting system - probably tuned even slower than 6Hz in the axial DOF. The vibration and noise comes from unintended contact of the pump with the stuff that is near it. Or through the semi-rigid plumbing.

Jim

[Randy G.]

Hi Randy,

Hope this is a move, not just a sight seeing trip.

Domobar Whatever will become of the Silvia epic?

I am plannning on hanging in this neighborhood for a month or two to see how things go. I will say that my wife said, "It's time..." I am contemplating making the move permanent. Fighting the good battle can make the typing fingers fatigued... all 4 of them!

I am trying to become accustomed to this format which is so different. It is coming along. I do wish there was a single page here for "All New Posts" in date order, in simple list showing subject, forum and maybe author so that all the various forums would not have to be viewed to see what is going on- a matter of old dogs and new formats, I suppose. On the other hand, with the active spell checking here you should find my posts far more palatable to the eyes!

And what WILL become of Silvia and her epic battle in the name of good coffee? Good question. If I find the Domobar to my liking Silvia will probably get 'bay'd. If I really like the VBM I probably will get a Mazzer and Rocky will go with her- shouldn't break up married couples anyway! I have a Baratza grinder for other uses, so that would work out well. After over 6 years of single boiler it was time to move on. I had been contemplating stepping up an I got a great deal on the VBM that I couldn't refuse.

I am quite busy as I have picked up two or three graphic/writing jobs over and above my current workload, so things will be busy here for the next month or two. After that, The VBM should supply enough info for a good review and some additional chapters on my website. Hope to be able to contribute to the bench article here as well. maybe.

Anyway, thanks for the welcome. It is nice to see so many familiar 'faces" here. Hope I don't drag down the intellectual level too far. In any case, moderation is a good thing!

[HB]

Welcome Randy! It was good to see you again at the SCAA conference and great to see you on HB. A few hints that you may find helpful...

I do wish there was a single page here for "All New Posts" in date order, in simple list showing subject, forum and maybe author so that all the various forums would not have to be viewed

The View recent topics link at the top right of the main forum page does this. If you login regularly, you may prefer the View unread posts link, which keeps track of the threads you've not read between sessions. You can clear the unread marks by forum or for all forums. The little mark unread link () on the right of each post allows you to add threads back to the list starting at a given point. This comes in handy if you marked all read and then decide you wish to return to a particular thread later (sort of a poor man's watch list).

Some of these features are stock phpBB, others are modifications I've added. A major upgrade to phpBB is in the works; it adds interesting features like bookmarking, "friends and foes", and tableless UI (loads faster). Ideas on how to improve the site are welcome in the Suggestion Box. Frequently the suggested improvements have already been implemented by another phpBB webmaster and it's a simple matter of integrating it (e.g., printer friendly topics, RSS feed, and related topics). For the rest, well, I've got years of programming experience to apply as needed.

[cannonfodder]

After that, The VBM should supply enough info for a good review and some additional chapters on my website. Hope to be able to contribute to the bench article here as well. maybe.

The more the merrier. Third party observations, corrections and user experience always help round out a bench test. That helps to keep the thread dynamic and more interesting.

FYI, the vibe pump on the Domobar Super is suspended above the frame in rubber mounts. I found most of the buzzing I got came from the drip tray and a loose gauge. A little electrical tape to isolate the vibration and reseating the gauge in the opening took care of most the noise. The next set of posts are a close look at the interior of the machine.

[hbuchtel]

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.

full post

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.

full post

Putting these two posts together- if you mounted the pump as gtrman suggested would it significantly reduce the strength/output of the pump (as Richard/espressme writes)?

If so, it seems that the best solution (also posted in this thread) would be to make the machine as solid as possible and not worry about the pump...

Henry

[Momma]

Just bought a Salvatore Semi and understand its a vibe. THEN, I read this post. Boy, timing is everything, isn't now? Anyway, the point is I understand he uses a separate frame inside the housing to isolate some of this. I'll let you know how successful that is in a couple of weeks when it arrives. I'm hoping its not as noisy as some of these other machines, because we will be having music one night a week.

I'll check back and let you know.... unless someone out there has one and can report immediately.... I would love to know now. Check is still sitting in the envelope to be mailed tomorrow.

Thanks,

[AndyS]

Putting these two posts together- if you mounted the pump as gtrman suggested would it significantly reduce the strength/output of the pump (as Richard/espressme writes)?

No, I don't believe so. Although "the vibe pump depends upon the reaction of the innerd's along the axis of the outer part," that doesn't mean a flexible mount will prevent it from operating normally.

[espressme]

And, most vibe pumps are mounted on flexible mounts. See the post of HB on the previous page. The external mounting is a good choice. The Salvatore could be done that way. Also, Salvatore has a rotary pump system available. Many folks mount the rotary pump under the counter. There are also carbonaters available to obtain a large motor /cheap pump. Ask Salvatore if he would set the machine for external fill. The fitting is in addition to the pourover reservoir.
my 1¢
richard

No, I don't believe so. Although "the vibe pump depends upon the reaction of the innerd's along the axis of the outer part," that doesn't mean a flexible mount will prevent it from operating normally.

[mathias]

The flexible mounts for vibe pumps I've seen on home machines where not tightened well enough to the machine body with the result they really did not work. Once firmly tightened the noise was reduced a lot (use big washers).

[Psyd]

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

Remember that water is a superior conductor of sound, and is not compressible, so that any pressure in the pipe twenty feet away is the same pressure in the machine. Same reason your car stops when you push on the pedal.

Sound is simply vibrations of air molecules, compressions and rarefactions. Look for things that will move a lot of air (side panels, top panels, etc.) and find ways to isolate them from the pump, as opposed to isolating the pump form them. It's just another way to look at the problem. Start with the moving air, and work your way back to the source. Truth be told, if you have a pump in free air, it makes very little noise. Quite a bit of the noise heard in the bedroom of sleeping mates is transferred through the counter, and the framing of the house. Low frequencies like 60 Hz tend to be difficult to stop, whereas shorter wavelengths tend to get dissipated over distances more easily.
Another tack to take with pump mounting is weight. If add a fairly large weight to the base of the pump, and them spring it, it makes the actual moving parts to static parts weight ratio large enough that the working parts aren't as able to make the chassis move, thereby reducing vibrations and reducing noise. Mass is usually your friend in dealing with low frequencies.

Oh, and you can do the mods or the manufacturer can do the mods. It's only money.
The reason that most of them make a lot of noise is that the coffee is the same, loud or quiet, but the machine is far more expensive quiet and most people don't listen to it when they buy, they look at the price tag.

[lorrin]

Interesting discussion. If you isolate the pump from the machine the machine is isolated from the pump Anything restricting air flow around the pump is a bad idea. Anyone got a spare coil for an Ulka?

The pump innerds work against the coil which can be isolated from the rest of the machine. That is what the rubber mounts are for. Mounting the rubber mounts to a hunk of material like a 1/4 inch thick by 2 inch wide piece of stainless steel and then mounting this on rubber mounts to the machine would help. Also make sure the plumbing lines leading to and from the pump are flexible and have a curve in them.

As pointed out some vibration can be coming from the water in the plumbing which also will be damped out with the flexible lines. These pressure pulses will get worse as it comes to pressure.

I never thought the noise was that bad. The proper isolation of the pump shouldn't be much of a price difference and sounds like it could be a big selling point. You could always turn up the radio.

Lorrin