# How does a vacuum cleaner produce vacuum? **URL:** \ **Category:** Factual Questions\ **Created:** [August 1, 2001, 5:05am UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442 "2001-08-01T05:05:12Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Major\_Feelgud](https://avatars.discourse-cdn.com/v4/letter/m/3be4f8/32.png) [@Major\_Feelgud](https://boards.straightdope.com/u/Major_Feelgud)\ **Post date:** [August 1, 2001, 5:05am UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442/1 "2001-08-01T05:05:12Z")
And why is it so loud? They seem to be rated as 25 amps or 40 amps, etc., what do those ratings mean? Is there a better way to filter the vacuumed air than blow it out through a filter bag? And I suppose those whirlwind ones where you see the stuff inside whirl around is just for show? How come some are $75 and some are $500? What’s the best vacuum out there? ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [August 1, 2001, 5:40am UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442/2 "2001-08-01T05:40:31Z")
I only answer one for free, then it’s $4.95 a minute. A vacuum cleaner is just a centrifugal pump, just like a water pump. That’s the noise you hear. The air is pumped out by centrifugal force and other air is sucked in to replace it. The more powerful the motor, the more “vacuum” it produces. Fairly simple. ---
**Author:** ![Major\_Feelgud](https://avatars.discourse-cdn.com/v4/letter/m/3be4f8/32.png) [@Major\_Feelgud](https://boards.straightdope.com/u/Major_Feelgud)\ **Post date:** [August 1, 2001, 6:21am UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442/3 "2001-08-01T06:21:09Z")
Thanks, I think. But what is a centrifugal pump and how does it work? For that matter, how does a water pump work? ---
**Author:** ![Trucido](https://avatars.discourse-cdn.com/v4/letter/t/ea5d25/32.png) [@Trucido](https://boards.straightdope.com/u/Trucido)\ **Post date:** [August 1, 2001, 6:41am UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442/4 "2001-08-01T06:41:11Z")
All shall be revealed in good time… I just love howstuffworks. > **[How Vacuum Cleaners Work](https://home.howstuffworks.com/vacuum-cleaner.htm)** > > Electric vacuum cleaners have been helping us keep our homes clean for over a century. There's a lot going on inside these devices -- learn how they suck up the dirt (and whatever else finds its way onto your floor). ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [August 1, 2001, 6:52am UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442/5 "2001-08-01T06:52:57Z")
A centrifugal pump uses centrifugal force (truth in advertising!) to move the fluid. The fluid enters the impeller chamber near the center and the rotating impeller pushes it away from the center and into the exhaust port. And as a picture is worth more than a few words check out: [http://www.howstuffworks.com/vacuum-cleaner1.htm](http://www.howstuffworks.com/vacuum-cleaner1.htm) Centrifugal pumps rely on the mass of the fluid being pumped. The more dense the fluid, the easier it is to pump. Air is not as heavy as water and so needs higher speed and greater rotor diameter. Check out [http://www.excelpump.com/html/\_\_a.y.\_mcdonald.html](http://www.excelpump.com/html/__a.y._mcdonald.html) for basic centrifugal pump principles. ---
**Author:** ![Major\_Feelgud](https://avatars.discourse-cdn.com/v4/letter/m/3be4f8/32.png) [@Major\_Feelgud](https://boards.straightdope.com/u/Major_Feelgud)\ **Post date:** [August 1, 2001, 9:11am UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442/6 "2001-08-01T09:11:53Z")
Thanks, I had forgotten about that website. ---
**Author:** ![xizor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/xizor/32/102_2.png) [@xizor](https://boards.straightdope.com/u/xizor)\ **Post date:** [August 1, 2001, 1:50pm UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442/7 "2001-08-01T13:50:47Z")
> [@](#): > > \*Originally posted by Major Feelgud \* > **Is there a better way to filter the vacuumed air than blow it out through a filter bag?** My Rainbow vacuum uses water as a filter. ---
**Author:** ![curwin](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@curwin](https://boards.straightdope.com/u/curwin)\ **Post date:** [August 1, 2001, 2:23pm UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442/8 "2001-08-01T14:23:25Z")
I can’t answer the OP, but it does remind me of a great joke: Did you hear about the Microsoft vacuum cleaner? It’s the only thing they make that doesn’t suck. ---
**Author:** ![Ike\_Witt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ike_witt/32/283_2.png) [@Ike\_Witt](https://boards.straightdope.com/u/Ike_Witt)\ **Post date:** [August 1, 2001, 6:18pm UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442/9 "2001-08-01T18:18:20Z")
These [Tri-Star](http://www.totallyvacuums.com/REFURBISHED_VACUUM_CLEANERS19287.html) vacuums rock. They can suck a golf ball through a garden hose. The refurbished one in the link is selling for $595. I bought a new one (since stolen) for $1200CDN about 12 years ago. ---
**Author:** ![cornflakes](https://avatars.discourse-cdn.com/v4/letter/c/9d8465/32.png) [@cornflakes](https://boards.straightdope.com/u/cornflakes)\ **Post date:** [August 1, 2001, 7:28pm UTC](https://boards.straightdope.com/t/how-does-a-vacuum-cleaner-produce-vacuum/74442/10 "2001-08-01T19:28:40Z")
> [@](#): > > \*Originally posted by Major Feelgud \* > **…They seem to be rated as 25 amps or 40 amps, etc., what do those ratings mean?** It’s the electrical current that the vacuum draws while in operation, which may or may not represent how strong the vacuum is. Assuming you live in the US, a 25 or 40 amp rating on a 110V appliance means that your vacuum cleaner isn’t UL listed and isn’t safe. The standard 110V electrical outlet in the US is rated for 15 amps. Anything more requires a different outlet.