Advantage of larger diameter on vacuum cleaner hose?

[gremlin_95]

Hi all,

My Numatic George vacuum cleaner comes as standard with a 32mm hose for dry use which is 1.9m in length, I was on the look out for a new hose and gave Numatic a call asking what different lengths can be obtained. The chap told me it is possible to also use a 38mm hose on the vacuum, however when asked what the advantage would be, he couldn't really answer.

Is there any advantage at all of having a 38mm hose, apart from the obvious that larger objects wont block the hose as easily as they would with a 32mm hose...

[mogga]

Pick up the stuff that is big enough to block the hose!

You'll just get bigger furballs evolving up there!

[Moonraker]

My logic, which is often faulty, tells me that the vacuum at the hose end would be lower, so would not suck up as well.

[Chris Hogg]

I assume it's a concertina type hose. If so, I find that when under suction, they tend to contract on themselves (shorten) to a certain extent, requiring 'pull' to keep them extended IYSWIM. The bigger the hose diameter, the bigger the 'pull' needed.

As to sucking up larger objects, presumably the fittings at each end are the same which will probably be the limiting factor controlling the size of objects that will go through, rather than the hose itself.

[RJS]

Ha Ha! Exactly my recent experience.

I'm finding that my new Nilfisk was supplied by a very narrow, concertina, hose which blocked at every opportunity. It now has a full-bore tube and has yet to block. Also, the motor sounds much less frantic with the bigger tube.

Richard

[gremlin_95]

Did it make much difference to the suction?

[The Medway Handyman]

Your logic isn't far wrong.

A bigger hose will mean lower 'suction' (not vacuum) but higher airflow.

Its a trade off. The suction alone isn't any good without enough airflow to move the debris along the hose. It depends on what you are picking up.

Small relatively heavy objects are best picked up by machines with high suction, lighter bigger objects you are better off with higher airflow.

With twin motor vacuums, where the motors are in parallel the suction remains the same, but the airflow doubles.

Commercial carpet cleaning machines often use twin vac motors to remove water from carpets, but they are used in series. The suction increases by about 25% and the airflow by about 50%.

[gremlin_95]

Thanks for that explanation. It's mostly used for vacuuming cars. Think I will stick with the current 32mm hose. The larger Numatic vacuum with twin motors seem to have 38mm hoses and 80l/sec airflow as opposed to George with 40l/sec.

[grimly4]

And then overheat.

[RJS]

No, in fact I think that the suction actually improved because the motor was not struggling to pull the air through a narrow hose.

My, very old, AquaVac has a hose which is the same size as the prelacement hose for the Nilfisk and it will pick up 1/4 bricks!

It's interesting to note that the narrow hose issued with the Nilfisk has an adaptor to make if fit the big-bore hole on the collection tank. I've asked Nilfisk why the supply the narrow hose.

Richard

[RJS]

So, am I missinterpreting the quieter motor noise caused by the larger hose allowing greater air flow when I concluded that the motor sounded as though it was under a lower load? Sorry if that's really convoluted!

Richard

[Gazz]

Depends on the diameter of yer c*ck, some people find the standard 32mm hose chafes a fair bit during a vacuum assisted milking session.... so i've been told.

I'm remembering the subject on here last year about the hoover nozzle that sliced the power cord in half, and all the suggestions that went with it, few days later i was in john lewis, and picked up the dysoon handheld vac on display, battery was full, so turned it on and blocked the end with my palm, the motor then started pulsing on and off, my GF burst out laughing, and said 'typical, i can buy a vibro for under a tenner, yet the male equivalent is over a hundered quid!'