Why has nobody invented a silent vacuum cleaner?

Question

the noise of a vacuum cleaner drives me nuts, I think it really sucks. If we can send someone to the moon how come we can't make a silent one?

Answer 1

Best Answer - Chosen by Asker

The technology exists, but it would be expensive. As Adam points out, turbulent air flow and motor whine cause the noise mostly, but these are confined to the motor/impeller system. Flow elsewhere is mostly laminar (smooth), so doesn't make much noise (just a sucking sound). You'd probably have to enclose the motor/blower in a can with evacuted walls, much like a thermos bottle has. Vacuum doesn't transmit sound. And, you'd have to pass the intake and exhaust air through a honeycombed collimator to prevent turbulence from getting out. You'd also have to use active noise suppression technology (like on expensive headphones) to prevent the noise passing through the honeycomb. I've read that such technology is actually being studied (at least) for air conditioning duct work.

All in all, it might add a couple hundred bucks to the cost of the vacuum cleaner and increase its bulk somewhat. Maybe it could be used on a high-end unit like you see that English inventor guy go on-and-on about on the commercials.

Asker's Rating:

Asker's Comment:

very illuminating, thanks

Answer 2

That's a brilliant question. Silent hairdryers too.

Answer 3

I made one that was silent but it sucks.

The earliest vacuum cleaners made much less noise because they were built into the house. There were sockets much like power sockets in each room. A motor ran the suction for the socket network and you just connect your hose in the room that you are in. Since the motor was placed far away from the room the only noise that you got was the rushing of the air. There is nothing that you can do about that.

Answer 4

they have
:)

Answer 5

The noise from a vacuum cleaner comes from the need to push the air out the exhaust quickly to create a partial vacuum to suck up the dirt with.

Nobody's been able to develop a set of baffles that will muffle the sound of the exhausted air well enough yet without impairing the effectiveness of the cleaner.

Answer 6

What a great idea, and a great question. It would make the inventor a fortune.

Answer 7

Simple, the size of the components to damper the noise and muffle the sound would make it so big that you wouldn't be able to move it. They have enough trouble making a regular vacuum light enough for everyone to easily handle.

Answer 8

Yeah, really! I hate the noise myself.

Answer 9

In a nutshell, you can't design something that works based on turbulent airflow and air pressure differential and expect it to be quiet, because fluctuations of air pressure = sound.

The best you can do right now, is get a central vacuum system, which puts the noisy high-rpm motor in your basement, and the motor whine is a big contributor to the vacuum cleaner's overall noise output. You can still hear the motor through the central vac plumbing, but it's not as loud as when it's in the room with you.

Answer 10

I invented such silent vacuum cleaner, but failed to
explain the principle to my wife. She could not hear me
because of horrible noise made by her vacuum cleaner.

Answer 11

It is the cost!! They have got tools to suppress the noise but if they bundle these with standard vacuum cleaners then the price would become uncompetitive. Same principle applies to old dot-matrix printers which required a hood to suppress the noise.