Talk:Mechanical fan

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Questions on ventilation[edit]

This will be post #1. I'm not sure if this is a forum where I can ask questions, but I hope so. So here goes:

I'm a product designer currently working on a project that will blow bubbles through fluid. One possible air propulsion method would be to use a centrifugal fan. The dimensions and characteristics work nicely with the product. However, the air flow/motor direction would work best reversed. I wonder what effect on the efficiency/effectiveness of a centifugal fan would be. It would be drawing air in and pushing it out the center port. Also, if it matters, we could probably lose most of the outer housing as the input can be all the way around the circumference. Thanks for any help! -kevin Salukikev 00:34, 14 November 2007 (UTC)

No, it's not a forum where you can ask questions, unless they're directly related to the article. I'm sure you could find that kind of technical information elsewhere. Try Googling it. SteveRamone 00:39, 14 November 2007 (UTC)

There should be a lot more here[edit]

I'm surprised there is not much about the mechanical fan on Wikipedia.. My fatehr said that during WWII there was no commercially available fans, and that some men in the navy were selling fans to consumers as a side project. He says he believes that the Vornado fan might have come out of that project. But I was hoping to find information about that here. And it seems that this is one area where Wikipedia is failing miserably at covering. (talk) 16:29, 22 June 2010 (UTC)

Cross flow fan[edit]

I've tried googling "cross flow fan", to learn more about its principle of operation. It seems it's not entirely similar to the cetrfugal fan, but Google did not really turn up anything useful. Maybe someone knowledgeable could expand the section in this article? An illustration similar to the centrifugal fan would be great! Thanks! europrobe (talk) 08:40, 7 June 2008 (UTC)

There is an Unmanned Aerial Vehice called FanWing that uses a cross flow fan. There are videos of this aircraft on YouTube and the companies website which are helful in getting to grips with what a cross flow fan is. Also there is a journal/paper called 'An Experimental Study of Cross Flow Fan' by S Murata. —Preceding unsigned comment added by (talk) 13:23, 20 February 2009 (UTC)
The Cross Flow fan (blower) is pretty rare. The most common applications for these fans in consumer products was a popular style of hair dryer that I haven't seen in years, and sometimes in air cleaners and over the range microwave vent fans. In my experience, a centrifugal blower (with backward inclined blading) is called a centrifugal blower. A squirrel cage blower (forward inclined blading) is what is used in almost every HVAC unit. These two subsections of this article are inaccurate. MicahWes (talk) 03:30, 17 February 2013 (UTC)
Cross flow is mainly used where the airflow needs to span across a wide, flat area, such as a circuit board inside a printer or copier, or for cooling the wide hot fuser rollers in a printer. The squirrel cage speed spanning the width can be relatively slow and only has two bearing points and one motor, as opposed to an array of many small fans that each have their own bearings, motors, and wires. -- DMahalko (talk) 21:18, 21 February 2013 (UTC)

Solar powered fan section: delete?[edit]

Is the section on solar powered fans needed? It seems like a special use case that doesn't require a different type of fan (except for low-power DC, which is mentioned elsewhere). Dan Griscom (talk) 04:28, 8 July 2008 (UTC)

Turbine fan for organ[edit]

A type of fan that is related to the cross flow principle that I have not seen here is the turbine type fan utilized in blowing wind into the air supply of pipe organs. The most common of these is the Spencer "Orgablow"T.M. kinectic blower. It utilizes jet turbines powered by a centrifigal/direct-drive split phaze motor having from five to fifty horsepower (or more) depending on the size of the pipe organ and number of pmeumatic components it contains as well as providing wind to blow through the pipes and rezonators. Ancient instruments were hand or foot 'Pumped' by paid 'bellows blowers' who had to manually supply the pipe organs wind. After the invention of electricity, the blower, both squirel cage type, and kinectic were used as the wind supply and are to this day. The kinectic blower can also have another identical blower attached directly to its feed out to increase the maximum available wind pressure for the organ. A large reservoire bellows, weighted with lead or brick weights regulates the wind pressure in the organ. If the organist suddenly brings on the full organ in a loud passage, the drop in wind pressure causes the reservoire bellows to expand instantly allowing the full kinectic and instantanious wind pressure to the pipes, causing them all to speak accordingly, and when the note is released, the bellows falls under the weight of the counter weights. The kinectic blower's invention has made possible the huge organs notably in the United States from the twentieth century to the present. The largest organ in the world is said to be the Midmer-Losh pipe organ in the Atlantic City Auditorium in New Jersey. This organ has over forty-thousand speaking pipes, the larges being sixty-four feet, and the smallest, smaller than a long cigarette. The keyboard console has seven manuals (keyboards) that control the instrument. Several kinectic blowers are necessary to blow this organ! Thus, the cross blown principle is made use here in the kinectic blower, causing, as has been illustrated above, a displacement of the actual size of the impeller or turbine, and that of the occupied space of a utilized burst of wind, whether steady or transient, displacing the entire space of the pipes, the air ducts, and the pmneumatic motors. (talk) 22:36, 26 January 2009 (UTC)

Bladeless fan?[edit]

The bladeless fan section should be removed, or edited to reflect that the so-called bladeless fan isn't really a different type of fan, but an application of a fan in which air from the fan in the unit's base is blown over the airfoil in the top of the unit to induce airflow through the duct. The arrangement is similar to a blown flap on an aircraft. Tesla4D (talk) 23:22, 5 October 2010 (UTC)

To add to this; a bladeless fan is still a fan, but the outdated definition in the article would suggest that a bladeless fan is not a fan. I think we should just define a fan as "a machine which blows gas" or something along those lines. Owen214 (talk) 13:35, 14 November 2010 (UTC)

Bladeless Fan 2[edit]

I agree that the blade-less fan section should be removed, as the manner in which air flow/pressure is produced appears to be conventional and fall under an existing category. The use to which that airflow is put would seem to be out of scope, except perhaps within a 'Fan-Applications' section. — Preceding unsigned comment added by Bathat (talkcontribs) 01:53, 8 December 2010 (UTC)

Bladeless Fan 3[edit]

Agreed. Indeed the new Dyson's desk fan is an ordinary radial-type fan (as seen on professional hair dryer) with a new kind of dissipator / difuser. Maybe really would be good a seccion about air blow applications. Lgugue (talk) 16:29, 14 December 2010 (UTC)

I have tried to edit the section to be more general and less like an infomercial. The term "bladeless" is marketroid language because what is an impeller? Oh, it's a type of bladed fan, but hidden inside the base. DMahalko (talk) 00:31, 16 April 2011 (UTC)

Thank you for clearing this up. I was under the impression, Dyson's bladeless fan was some kind of modified ion thruster. — Preceding unsigned comment added by (talk) 02:42, 1 April 2012 (UTC)

Another fan design ?[edit]

I made an image of another fan, but I'm not sure whether it allready exist allready. Image is

—Preceding unsigned comment added by (talk) 09:40, 20 April 2011 (UTC)

It's a creation of KVDP (talk · contribs) and (of course) it won't work. It's a redrawn derivative of two other images: one is itself incorrect. The other is of a water pump and won't work for Reynolds number of air at atmospheric pressure. Andy Dingley (talk) 13:01, 5 May 2011 (UTC)

in need of advice and help![edit]

Under what conditions and the following statement be removed from centrifugal compressor? "Cleanup|date=June 2008" centrifugal compressor is currently in a semi-complete state. It has not been proofread and has not been verified to standard that I would like to apply. I would like to ask for everyone's help to please review the article and make comments on the discussion page. I really will attempt to incorporate all of your improvements in a rigorous and consistent fashion. it is important that you are happy the way your issues are addressed. It is currently missing a section on "design methodology" that I would like to research and discuss before I complete. There are significantly different points of view that I would like to try to unify. the section on design methodology is not original work and will be properly referenced. All turbomachinery is unified by fundamental physics in the applied mathematics use in their design and analysis. That is why the term turbomachinery can be used as an umbrella topic. Dozens of academic textbooks attest to the above statement. Other than one other turbomachinery entry I have not been happy with the technical and scientific accuracy of any other encyclopedic entries. Most of these entries have been negatively impact by end-user and application colloquialisms. I will slowly, starting with centrifugal pumps and centrifugal fans try to correct various errors in statements. Unless I am asked I will not make any significant changes to the outlines of these encyclopedic articles. thank you for everyone's help martin koronowski, Mkoronowski (talk) 22:24, 30 April 2011 (UTC)

Unusual fan in article, can you identify it?[edit]

Luefter pd1270153b-2f.jpg

This is an unusual fan type I have heard about, but I do not recall the brand name of it.

Basically there is no drive motor in the center, and it is instead driven by a cylinder of magnets around the outside edge of the blades. Fixed electromagnets in the corners of the housing drive the hub to spin.

It is sufficiently odd as to be classified by itself but I just don't remember what this type of fan is called. I believe the goal is to be more efficient by moving the fan motor out of the center hub and providing more blade surface for air to flow.

The provided Commons image does not identify the fan model, and the side label is unreadable even at high magnification.

DMahalko (talk) 03:03, 19 July 2011 (UTC)

Sorry for late response, just seen this today. Manufacturer was Yen Sun Technology Corporation, Model number (pd1270153b-2f) is provided in the file name :-). This fan construction was intended to deliver better air flow in the center, where conventional fans have low flow (dead spot), especially for use on heat sinks. I found a photo of the inner construction here. -- Smial (talk) 14:15, 25 December 2011 (UTC)

axial fan... how it works?[edit]

In theory.

Axial flow fans work by "cutting" into the stationary air mass in front of the blade tips. Once air enters the blades, it begins to rotate with the blades, and continues to rotate even after it has been expelled. There is a point where very deep blades don't pump any more air because once the air enters and reaches the same rotational speed as the blades, the blades have no additional flow-enhancing effect. Also, the air on the intake side begins to spin due to air drag from the rotating intake blades, further reducing the fan efficiency.
Turbines, a more complex type of axial fan, counteract this rotational stalling effect by having alternate layers of stationary and rotating blades. The rotating blades cut into the stationary air mass held between the stationary blades, and the stationary blades cut into the rotating air mass held between rotating blades. In this manner the stationary blade stack enhances and multiplies the velocity of air passing through the rotating blade stack.

Though, need to find references to verify this. DMahalko (talk) 00:08, 29 February 2012 (UTC)

Reverse effect[edit]

Where can I find an explanation about why when you start a fan it seems to momentarily switch or reverse its spinning direction? — Preceding unsigned comment added by (talk) 10:01, 11 July 2012 (UTC)

Pankha, not pankah[edit]

Pankha is an Indian word, originating from the wings of a Bird (Pankh) which generates a draft when flapped, and not derived from the Mesopotamean civilisation, which uses words with 'Kah'. Hence, the word has been replaced by 'Pankha'. Bkpsusmitaa (talk) 12:34, 13 April 2013 (UTC)