CR4 - The Engineer's Place for News and Discussion ®


Previous in Forum: Re: Heat Required for Expansive Type (Ammonia) Refrigerator   Next in Forum: Alloy Steel 8620
Close
Close
Close
27 comments
Power-User

Join Date: Nov 2008
Location: kibbutz nir-david, a beautiful rural village in Israel
Posts: 303

Axial Fan Vacuum Pump

01/05/2017 6:46 AM

Dear aerodynamic experts: I need a single stage axial fan for low vacuum- about 0.5 atm.

Is it possible to gain such vacuum using only 1 rotor?

How much can be the maximal vacuum with a single rotor?

I tried to find information about it by googling, but I couldn't find anything relevant for me.

I wonder very much about this because it seems to me that there shouldn't be any problem.

Am I wrong when I asume that the design for a low pressure single stage axial compressor shoud be the same as for a single stage axial vacuum pump fan?

thank you in advance

azriel nativ

Register to Reply
Pathfinder Tags: axial fan+vacuum+compressor
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26071
Good Answers: 685
#1

Re: axial fan vaccum pump

01/05/2017 6:52 AM

A1) yes.

A2) the boiling pressure that corresponds with the temperature of whatever liquid is in the system to which the fan is connected.

A3) yes.

If in doubt, talk to (the) equipment vendor(s) using the telephone.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 19700
Good Answers: 737
#2

Re: Axial Fan Vacuum Pump

01/05/2017 10:51 AM

You need to sort out the terms fan, blower, compressor, and (vacuum) pump. A single-stage fan can't do what you want, and it might be tough for even a blower.

__________________
In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
Power-User

Join Date: Nov 2008
Location: kibbutz nir-david, a beautiful rural village in Israel
Posts: 303
#3
In reply to #2

Re: Axial Fan Vacuum Pump

01/05/2017 11:02 AM

Meanwhile I contacted a vendor for vacuum pumps, and he told me where I can get such a fan.

Register to Reply Score 1 for Off Topic
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 19700
Good Answers: 737
#4
In reply to #3

Re: Axial Fan Vacuum Pump

01/05/2017 11:27 AM

Let's see some details. (Or is there a typo somewhere?)

__________________
In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
Power-User

Join Date: Nov 2008
Location: kibbutz nir-david, a beautiful rural village in Israel
Posts: 303
#11
In reply to #4

Re: Axial Fan Vacuum Pump

01/05/2017 12:19 PM

No, I just the vendor if there are axial fans that are able to gain 0.5 atm. pressure or vacuum.

But since I need it only for an experiment, I wouldn't pay 2000 nis for a new fan. so I'm looking now for a 2nd hand.

Register to Reply
Guru

Join Date: Dec 2016
Posts: 2914
Good Answers: 115
#13
In reply to #11

Re: Axial Fan Vacuum Pump

01/05/2017 4:22 PM

Buy a used one and re-sell it when you're done with it. Maybe clean it up and sell it at a profit. People do that on eBay all the time.

Register to Reply
Power-User

Join Date: Nov 2008
Location: kibbutz nir-david, a beautiful rural village in Israel
Posts: 303
#17
In reply to #13

Re: Axial Fan Vacuum Pump

01/05/2017 11:34 PM

since I'm retired 78 yrs person, and still paying for music education of my daughter, 2000 nis, is very much money for me!

Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26071
Good Answers: 685
#19
In reply to #17

Re: Axial Fan Vacuum Pump

01/06/2017 3:16 AM

That is not Andrew Westman's problem.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Dec 2016
Posts: 2914
Good Answers: 115
#23
In reply to #17

Re: Axial Fan Vacuum Pump

01/06/2017 7:06 AM

"so I'm looking now for a 2nd hand."

Where did I quote a price, az native? I said buy a used one and re-sell it when you're done with it, possibly at a profit, no?

Register to Reply
Guru

Join Date: Jun 2009
Location: South of Minot North Dakota
Posts: 8125
Good Answers: 748
#25
In reply to #17

Re: Axial Fan Vacuum Pump

01/06/2017 2:40 PM

Tell her to get off her ass and get a job and pay for it herself like every other financially responsible person who wants a education beyond public level does.

I had to. Twice!

Register to Reply Off Topic (Score 5)
Guru

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 10440
Good Answers: 128
#5
In reply to #3

Re: Axial Fan Vacuum Pump

01/05/2017 11:30 AM

I think Obama could pull that much vacuum all by himself. I know he sux the air out of any room.

Careful with your new toy, not to get your butt stuck to the inlet.

You need at least 3 stages with axial vacuum pump, depending on how much air flow you require. You have to clean the air upstream, since dirt will kill your vacuum pump/compressor.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply Off Topic (Score 6)
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 17678
Good Answers: 1009
#7
In reply to #3

Re: Axial Fan Vacuum Pump

01/05/2017 11:37 AM

Could you share that information...?

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply
Guru

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 10440
Good Answers: 128
#8
In reply to #3

Re: Axial Fan Vacuum Pump

01/05/2017 11:47 AM

So now we know what job Obama has signed up for after leaving the job.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply Off Topic (Score 7)
Guru

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 10440
Good Answers: 128
#6

Re: Axial Fan Vacuum Pump

01/05/2017 11:31 AM

Why don't you try a centrifugal fan as the vacuum pump instead?

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Power-User

Join Date: Nov 2008
Location: kibbutz nir-david, a beautiful rural village in Israel
Posts: 303
#9
In reply to #6

Re: Axial Fan Vacuum Pump

01/05/2017 12:14 PM

because it doesn't fit for my purpose!

Register to Reply
Guru

Join Date: Dec 2016
Posts: 2914
Good Answers: 115
#15
In reply to #9

Re: Axial Fan Vacuum Pump

01/05/2017 8:51 PM

And what is your purpose?

Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26071
Good Answers: 685
#20
In reply to #15

Re: Axial Fan Vacuum Pump

01/06/2017 3:16 AM

Quite. This thread has become a guessing game.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru

Join Date: Sep 2016
Posts: 643
Good Answers: 7
#10

Re: Axial Fan Vacuum Pump

01/05/2017 12:16 PM

You mean to say lube, screw or vane type vacuum pump? I haven't heard an axial fan doing a vacuum pump operation except at the inlet gate/port of jet engines(not an axial fan either).

Register to Reply
Guru

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 10440
Good Answers: 128
#12
In reply to #10

Re: Axial Fan Vacuum Pump

01/05/2017 1:48 PM

Nearly 100% of gas turbines (jet engine to you) utilize the advanced axial compressor designs, based on German technology from WWII.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru

Join Date: Sep 2016
Posts: 643
Good Answers: 7
#16
In reply to #12

Re: Axial Fan Vacuum Pump

01/05/2017 11:04 PM

maybe the guy is looking such as these mini turbine use in RC planes

Register to Reply Score 1 for Off Topic
Guru

Join Date: Jun 2009
Location: South of Minot North Dakota
Posts: 8125
Good Answers: 748
#18
In reply to #16

Re: Axial Fan Vacuum Pump

01/05/2017 11:53 PM

Jet engine thrust pressures are not all that extremely high. Take a large engine like the Rolls Royce RB211 that has a fan diameter of 86.3 inches and a thrust of ~95,000 pounds.

That's a output ~ 16 PSI! That ain't much really and the OP is wanting a axial fan that can produce ~7 PSI of suction.

Same with a RC scale jet engine like a P400-RXG that produces ~90 pound of thrust with a ~5 inch fan that equates to a ~ 4.6 PSI output on a ~98,000 RPM fan speed. ~$6000!

To me asking for ~7 PSI of suction from a axial fan system for under $500 is way past unrealistic but then of what I have seen of the OP's general understanding and expectations of things in the past unrealistic is sort of his mode of operation anyway.

Register to Reply
Guru

Join Date: Jul 2005
Location: Stoke-on-Trent, UK
Posts: 3695
Good Answers: 110
#21
In reply to #18

Re: Axial Fan Vacuum Pump

01/06/2017 4:21 AM

Quite, and your examples have multiple stages, but he wants to do it in a single stage.

Single-stage axial fans have typical pressure rise 5 - 10mbar. Centrifugals give higher pressure rise, but only up to ~ 100mbar max.

__________________
Give masochists a fair crack of the whip
Register to Reply
Guru

Join Date: Jun 2009
Location: South of Minot North Dakota
Posts: 8125
Good Answers: 748
#26
In reply to #21

Re: Axial Fan Vacuum Pump

01/06/2017 2:50 PM

That was my point. It's not a realistic way to get such a degree of vacuum.

Axial fans are very poor for making vacuum by the basic physical methods they move air.

Centrifugal however, like used in turbochargers or centrifugal superchargers can make much higher vacuum levels but they run at very high RPM's to do it and even then they are no match for a simple postive displacement pump type system.

Personally I don't think the OP has a clue what he is doing or working with since he has yet to give one single reference to the application such as the basic air flow requirements involved despite being asked multiple times.

Register to Reply Score 1 for Good Answer
Guru

Join Date: Sep 2016
Posts: 643
Good Answers: 7
#22
In reply to #18

Re: Axial Fan Vacuum Pump

01/06/2017 4:46 AM

He could try a thin can like these kids did

Register to Reply
2
Guru

Join Date: Jun 2009
Location: South of Minot North Dakota
Posts: 8125
Good Answers: 748
#14

Re: Axial Fan Vacuum Pump

01/05/2017 7:18 PM

And what volume of air does it need to move to achieve said .5 ATM suction pressure?

Also what power input source and physical dimensions.

Also 2000 Nir is about $520 US dollars which won't buy you crap for high suction radial blower units.

It would barely get you a good used regenerative blower that may be capable of that suction level.

Also, why does it need to be an axial fan? By design they are typically not all that well suited to doing high pressure work regardless of their blade aerodynamics unless they are stacked with multiple blade sets in series. Centrifugal blowers on the the other hand are.

axial vs. centrifugal fans. General application of each.

Register to Reply Good Answer (Score 2)
Guru

Join Date: Dec 2016
Posts: 2914
Good Answers: 115
#24
In reply to #14

Re: Axial Fan Vacuum Pump

01/06/2017 7:41 AM

In a pinch I suppose he could move to La Rinconada, Peru and use a palm frond.

Register to Reply
Guru

Join Date: Nov 2012
Posts: 622
Good Answers: 13
#27

Re: Axial Fan Vacuum Pump

01/06/2017 2:54 PM

I used to refurbish Bruning microfiche duplicators...in that chassis there was a small vane compressor (10" or so) direct coupled to an integral motor, which I've also used as a low vacuum pump...it was like a junior version of the 3hp unit used on my sawdust collector and seemed to pull about the same amount of vacuum at a pretty decent volume...

Register to Reply
Register to Reply 27 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Andrew Westman (4); az native (4); Codemaster (1); geraldpaxton (1); gutmonarch (3); James Stewart (4); PWSlack (3); SolarEagle (1); tcmtech (4); Tornado (2)

Previous in Forum: Re: Heat Required for Expansive Type (Ammonia) Refrigerator   Next in Forum: Alloy Steel 8620

Advertisement