Sucking better than Blowing ?

Anything that does not fit elsewhere can be discussed here.

Moderators: DJKeefy, 4u Network

Post Reply
User avatar
Who2
Egyptian God
Egyptian God
Posts: 7911
Joined: Fri Jul 16, 2010 12:04 pm
Location: Laandaan
Has thanked: 1113 times
Been thanked: 3214 times
Gender:
United Kingdom

Sucking better than Blowing ?

Post by Who2 »

Good title post eh ?
During this warm spell my thoughts always turn to keeping cool.
The Question ? Can these cheap Chinese ceiling fans be reversed ? ie: to suck the cold air upwards, rather
than them pushing hot air down.
I have three expensive fans that do both summertime anticlockwise winter clockwise .
Answers on a postcard or just a post, cheers..... 8)
Ps: I ask because I have just had 8 calls from Souk.com
telling me my two new oscillating motion fans have arrived @ Gezira Gdns. (bakshesh)


"The Salvation of Mankind lies in making everything the responsibility of All"
Sophocles.
User avatar
Horus
Egyptian God
Egyptian God
Posts: 7933
Joined: Tue Oct 10, 2006 11:59 pm
Location: UK
Has thanked: 2431 times
Been thanked: 1870 times
Gender:
Contact:
United Kingdom

Re: Sucking better than Blowing ?

Post by Horus »

If your asking a serious question then the answer would be that a ceiling fan with fixed blades would be directional and as such the motor cannot be reversed being single phase, but the main thing would be the blade angle which would be the wrong shape if going in reverse.
Image
newcastle
Egyptian God
Egyptian God
Posts: 8695
Joined: Thu Oct 17, 2013 11:49 am
Has thanked: 1548 times
Been thanked: 5127 times
Contact:
Egypt

Re: Sucking better than Blowing ?

Post by newcastle »

If you can flip the fan over, it will solve your problem.

This may involve a certain amount of screwing to translate the blowing into sucking ;)
User avatar
Horus
Egyptian God
Egyptian God
Posts: 7933
Joined: Tue Oct 10, 2006 11:59 pm
Location: UK
Has thanked: 2431 times
Been thanked: 1870 times
Gender:
Contact:
United Kingdom

Re: Sucking better than Blowing ?

Post by Horus »

newcastle wrote:If you can flip the fan over, it will solve your problem.

This may involve a certain amount of screwing to translate the blowing into sucking ;)
You could always stick it on a pole upside down with a trailing lead across the floor ;)
Image
User avatar
Who2
Egyptian God
Egyptian God
Posts: 7911
Joined: Fri Jul 16, 2010 12:04 pm
Location: Laandaan
Has thanked: 1113 times
Been thanked: 3214 times
Gender:
United Kingdom

Re: Sucking better than Blowing ?

Post by Who2 »

Iv'e tried many forms of the blade angles, doesn't work.
How I know ? I use smoke to follow the air currents around the house...
The mud ceilings in these adobe houses normally also have a high-up hole to let out the hot air,
mine contains a very large voltage stabilizer..... 8)
Ps: This subject is a complicated one: Quote...
"Ceiling fans do not move air in the room in a homogenous manner. Bassiouny and Korah in 2011 studied the airflow patterns in a room due to a single rotating ceiling fan. They found that airflow was the lowest at two locations: at the ceiling fan hub (i.e., fan center) and at the fan blade tip. It is somewhere between the fan center and fan blade tip that airflow was the highest.

So, if we plot the airflow velocity (speed) at various distances along the fan blade length, we would observe that the airflow generated by a ceiling fan would increase from the fan center, reach maximum at somewhere midway of the fan blade length, and then decline moving towards the fan blade tip. This change in airflow velocity which rises then falls along the fan blade length is the so-called humped airflow profile.

Humped airflow profile, where airflow velocity increases from the fan center before reaching maximum (i.e., hump) at about midway of the blade length, then decreases along the blade length (Schmidth and patterson, 2001)
All ceiling fans display the so-called humped airflow profile, where airflow velocity increases from the fan center before reaching maximum (i.e., hump) at about midway of the blade length, then decreases farther along the blade length (Schmidt and Patterson, 2001).

'Simples ? I don't think so.... 8)
"The Salvation of Mankind lies in making everything the responsibility of All"
Sophocles.
User avatar
DJKeefy
Site Administrator
Site Administrator
Posts: 11025
Joined: Thu Jan 13, 2005 4:08 pm
Location: UK
Has thanked: 652 times
Been thanked: 1222 times
Gender:
Contact:
Egypt

Re: Sucking better than Blowing ?

Post by DJKeefy »

In one of the apartments I stayed in all the fans had the usual looking box with a knob which you turned clockwise to increase the speed of the fan, except these boxes had the knob in the centre position (which was off) If you turned it right it blew down air, turned it left and it sucked up the air, the fans looked no different to the normal fans you see in most apartments. :)
Image
User avatar
Who2
Egyptian God
Egyptian God
Posts: 7911
Joined: Fri Jul 16, 2010 12:04 pm
Location: Laandaan
Has thanked: 1113 times
Been thanked: 3214 times
Gender:
United Kingdom

Re: Sucking better than Blowing ?

Post by Who2 »

As the Winter here fast approaches....on a sunny Monday and only 42oC.
So as the "Nile fed plunge healing pool™ pending, is turning chilly Here, Is the 'mark 4 Winter water heater.....
15155
Note the bubbles it gets to a pleasant 38oC in 24 hrs and stays hot for 10 hours.
(Obviously! not connected in this picture)
Plus + I have a very clever Chinese Disco Ball that plays soothing Ambient 8gig memory stick
though a 'newly attached car speaker. 300le souk.com 'thats the light not the speaker!
Axel of JJ's Bar reckons they are also sound to light, "chill Winstone chill...
So The Dr is popping back to the 'Smoke next week,
hopefully rain, beer, smog, bacon butties, black pudding, a chilled bottle of Chevalier-Montrachet
and people who ignore a cheery morning "AsSalam Alaikum" ..... 8)
"Love London Love Life" Who said that ?
"The Salvation of Mankind lies in making everything the responsibility of All"
Sophocles.
User avatar
Major Thom
Royal V.I.P
Royal V.I.P
Posts: 2885
Joined: Mon Mar 30, 2015 5:45 am
Has thanked: 187 times
Been thanked: 375 times
Gender:
Contact:
Cyprus

Re: Sucking better than Blowing ?

Post by Major Thom »

Try looking for a proper fan control box with speeds and fan direction on. I used them many years ago for Expelair extractor fans, so would imagine that they would do the same for ceiling fans. Google Expelair Fan Controllers.

Of course if it was 3 phase then it would just be a matter of changing 2 of the phases around.
User avatar
Who2
Egyptian God
Egyptian God
Posts: 7911
Joined: Fri Jul 16, 2010 12:04 pm
Location: Laandaan
Has thanked: 1113 times
Been thanked: 3214 times
Gender:
United Kingdom

Re: Sucking better than Blowing ?

Post by Who2 »

Hmm! the control box. If it was that simple it might just have slipped under my radar..
Sadly not, it's the motor rather than the control box that determines it's direction.
A good try to say the least, don't give up the day job... 8)
"Marks out of 10 = 2 for effort could do better...
"The Salvation of Mankind lies in making everything the responsibility of All"
Sophocles.
User avatar
Major Thom
Royal V.I.P
Royal V.I.P
Posts: 2885
Joined: Mon Mar 30, 2015 5:45 am
Has thanked: 187 times
Been thanked: 375 times
Gender:
Contact:
Cyprus

Re: Sucking better than Blowing ?

Post by Major Thom »

The Expelair control unit has all the works in it and takes over the control of the motor on the fan unit Dr. The controller itself is more costly than the fan in most cases, but does the job by reversing electrical fields, and a rheostat to control the speed.
User avatar
Who2
Egyptian God
Egyptian God
Posts: 7911
Joined: Fri Jul 16, 2010 12:04 pm
Location: Laandaan
Has thanked: 1113 times
Been thanked: 3214 times
Gender:
United Kingdom

Re: Sucking better than Blowing ?

Post by Who2 »

Far to complicated an operation for me to perform.... 8)
https://woodgears.ca/motors/reversing.html
"The Salvation of Mankind lies in making everything the responsibility of All"
Sophocles.
Post Reply