Twin Fan Uprights - physics question for engineers out there

[eurekaprince]

In the 1950’s, Singer came out with their sleek revolutionary upright that offered a sideways-positioned motor with a fan on each side. This “twin-fan” upright design survived well into the 1970’s in the form of upright vacuums branded as Singer, Kenmore, Lewyt and Sunbeam. But these uprights never seemed to top Consumer Reports ratings for deep carpet cleaning….they were always outperformed by competitors’ uprights created by Eureka, Hoover and Panasonic.

Which brings me to a bit of a science question maybe someone could answer: is it possible that having two fans each creating a suction pull on each side of the brush chamber is actually counter-productive? In other words: is it possible that this design actually creates less effective air flow in the brush roll chamber because each fan is trying to pull air away from the other fan - thereby negating the suction pull on each side?

Thoughts?

 

[cheesewonton]

In the 1950’s, Singer came out with their sleek revolutionary upright that offered a sideways-positioned motor with a fan on each side. This “twin-fan” upright design survived well into the 1970’s in the form of upright vacuums branded as Singer, Kenmore, Lewyt and Sunbeam. But these uprights never seemed to top Consumer Reports ratings for deep carpet cleaning….they were always outperformed by competitors’ uprights created by Eureka, Hoover and Panasonic.

Which brings me to a bit of a science question maybe someone could answer: is it possible that having two fans each creating a suction pull on each side of the brush chamber is actually counter-productive? In other words: is it possible that this design actually creates less effective air flow in the brush roll chamber because each fan is trying to pull air away from the other fan - thereby negating the suction pull on each side?

Thoughts?

I suspect that other aspects of the vacuum's design led to it being less competitive. Without reading the tests however I can only speculate. Panasonic would be a clean air model with a higher amp motor than those old Singer's used and because it is clean air it would have more suction. Hoovers had especially aggressive brush rolls. Tacony makes a modern twin fan model of their own sold under the Carpet Pro brand name that I have been tempted to buy.

 

[centralsweeper63]

Good points. They got half of the equation, but not the other half.

 

[vacuumman]

In the 1950’s, Singer came out with their sleek revolutionary upright that offered a sideways-positioned motor with a fan on each side. This “twin-fan” upright design survived well into the 1970’s in the form of upright vacuums branded as Singer, Kenmore, Lewyt and Sunbeam. But these uprights never seemed to top Consumer Reports ratings for deep carpet cleaning….they were always outperformed by competitors’ uprights created by Eureka, Hoover and Panasonic.

Which brings me to a bit of a science question maybe someone could answer: is it possible that having two fans each creating a suction pull on each side of the brush chamber is actually counter-productive? In other words: is it possible that this design actually creates less effective air flow in the brush roll chamber because each fan is trying to pull air away from the other fan - thereby negating the suction pull on each side?

Thoughts?

Off the top of my head, I know that the Singer Magic Carpet series has a floating brushroll that doesn't make contact with the carpet super well, so that may put it at a disadvantage.

I feel like the air in a twin fan setup is more likely to take the path of least resistance through the nozzle rather than pull against the other motor, but I am not 100 percent sure.

 

[centralsweeper63]

It would work, as long as the pressure is the same from both motors, like on a parallel motor central vac.

 

[cheesewonton]

It would work, as long as the pressure is the same from both motors, like on a parallel motor central vac.

It is one motor laying on its side with a fan on either end of the armature shaft.

 

[blackheart]

I don't really know the physics behind it but I've tested at least 2 vacuum with a twin fan setup, that singer as seen above and a piranha upright which was made by tornado, based off of the bissell prolite design.
Usually in parallel settings the flow is boosted but this is a unique case where we have parallel airflow sources powered by one motor meaning that motor is getting all of the resistance in addition to that they also funnel all of the air into a single channel.
It's been my experience so far that there's not too significant a benefit to this design IF there even is one. The Singer I tested scored below many direct air single fan machines like the hoover convertible or Eurekas, The piranha though did slightly better than most if not all of the other lightweight direct air machines I've tested so far but only by about 5-6 cfm
The design *may* lead to better distribution of the airflow across the nozzle but that's speculation.

I'm not sure I'd say it's counter productive fluid will follow the path of least resistance and being powered by the same motor their suction should be equal I will say it definitely seems less efficient than just having one larger fan and a single airpath.

 

[ultralux88]

On that note, maybe I'll run my Power-Flite wide thing and see. To me it seems similar in airflow to something like a Sanitaire that uses one large fan. I always thought the height adjustment and to a degree the bottom plate design could have been better, and slowed for better use of the airflow it does have.

 

[centralsweeper63]

That would work well too.

 

[cheesewonton]

I don't really know the physics behind it but I've tested at least 2 vacuum with a twin fan setup, that singer as seen above and a piranha upright which was made by tornado, based off of the bissell prolite design.
Usually in parallel settings the flow is boosted but this is a unique case where we have parallel airflow sources powered by one motor meaning that motor is getting all of the resistance in addition to that they also funnel all of the air into a single channel.
It's been my experience so far that there's not too significant a benefit to this design IF there even is one. The Singer I tested scored below many direct air single fan machines like the hoover convertible or Eurekas, The piranha though did slightly better than most if not all of the other lightweight direct air machines I've tested so far but only by about 5-6 cfm
The design *may* lead to better distribution of the airflow across the nozzle but that's speculation.

I'm not sure I'd say it's counter productive fluid will follow the path of least resistance and being powered by the same motor their suction should be equal I will say it definitely seems less efficient than just having one larger fan and a single airpath.

Pretty sure the Bissell Prolite is a Tacony product. Carpet Pro, Tornado and other Tacony brands have their own versions.

 

[ultralux88]

Pretty sure the Bissell Prolite is a Tacony product. Carpet Pro, Tornado and other Tacony brands have their own versions.

It wasn't when it was a Bissell. Tacony and Bissell traded intellectual property a while ago. Tacony used to use the name "Healthy Home" on the bags for Simplicity vacuums and EcoPure on the Riccar ones. For whatever reason, Bissell was dead set on using the name Healthy Home on their new bagless machine at the time, and Tacony had the issue that the SupraLite, which was originally developed by and for Powr-Flite so they could retire the old Singer twin fan style machine they had been selling to compete with Orecks for light weight commercial machines, had been taken over by Riccar and Simplicity, and dealers were feeling they had the right to tell Tacony to not let Powr-Flite sell it, or at least not at the price they were. Ultimately, Bissell traded the Prolite's manufacturing rights, molds and design for the name Healthy Home.

 

[centralsweeper63]

Cool!

 

[cheesewonton]

It wasn't when it was a Bissell. Tacony and Bissell traded intellectual property a while ago. Tacony used to use the name "Healthy Home" on the bags for Simplicity vacuums and EcoPure on the Riccar ones. For whatever reason, Bissell was dead set on using the name Healthy Home on their new bagless machine at the time, and Tacony had the issue that the SupraLite, which was originally developed by and for Powr-Flite so they could retire the old Singer twin fan style machine they had been selling to compete with Orecks for light weight commercial machines, had been taken over by Riccar and Simplicity, and dealers were feeling they had the right to tell Tacony to not let Powr-Flite sell it, or at least not at the price they were. Ultimately, Bissell traded the Prolite's manufacturing rights, molds and design for the name Healthy Home.

I had no idea any of that happened.

 

[centralsweeper63]

With my comment about the pressure being the same, a chipped or damaged fan could cause that to be a problem.

 

[cheesewonton]

I have always thought the twin fan was a great design in that you have even suction across the entire width of the nozzle but in the case of most Singers poorly executed. If you look at the S3 that thing is all metal and exquisitely well made. The materials and machining are really eye popping, better than a lot of car engines from that era. Compared to 1980s Hoover uprights the Singers didn't have much power, only 6 point something amps where Hoover Elite variants were 7-12 amps depending on the model so naturally they made the Singers look kind of weak.

 

[centralsweeper63]

That does make sense.

 

[eurekaprince]

I don't really know the physics behind it but I've tested at least 2 vacuum with a twin fan setup, that singer as seen above and a piranha upright which was made by tornado, based off of the bissell prolite design.
Usually in parallel settings the flow is boosted but this is a unique case where we have parallel airflow sources powered by one motor meaning that motor is getting all of the resistance in addition to that they also funnel all of the air into a single channel.
It's been my experience so far that there's not too significant a benefit to this design IF there even is one. The Singer I tested scored below many direct air single fan machines like the hoover convertible or Eurekas, The piranha though did slightly better than most if not all of the other lightweight direct air machines I've tested so far but only by about 5-6 cfm
The design *may* lead to better distribution of the airflow across the nozzle but that's speculation.

I'm not sure I'd say it's counter productive fluid will follow the path of least resistance and being powered by the same motor their suction should be equal I will say it definitely seems less efficient than just having one larger fan and a single airpath.

Thanks for your reply Blackheart. Very interesting. The only way we could know for sure is to test the airflow using a hose adapter/pan converter that used to be offered with the Twin Fan uprights. You would compare the suction gauge readings on the port of the converter (with the hose not attached obviously) - one with both impellers in place, and another with one impeller removed if it is easy to remove it. I guess you would remove the impeller on the side without the brush roll belt to measure the suction as if it is was a regular single fan vacuum. To make the comparison even more fair, you would have to somehow block off the air channel on the side where the impeller was removed.

I think the only way a Twin Fan upright could really improve cleaning is if the brush roll chamber were completely split into two separated chambers, with two separate half-length brush rolls like some of the European Vorwerk Kobold brush nozzles have. That way, each fan would be pulling air separately in its own separate brush roll chamber.

Thanks for everyone’s responses!

 

[dysonman1]

You can hardly talk about twin fan upright vacuums without talking about the company that invented them and perfected it. Singer stole the idea from Air-Way's DirtMasteR which successfully used twin rotating suction fans in 1935. In 1960 General Electric turned their motor sideways, surrounded it with a "ball", and marketed it as their extremely lightweight easy to use upright. The singer design was always crap. Whether it was a Kenmore, singer, Sunbeam, or any of the other brands they stuck on the machine. It was loud, dusty, and didn't clean very well by the very design of the machine. Not the fact that it had double fans. As far as the Bissell pro light design and Tacony, there is so much I never told people that I saw while I was there for 10 years. You wouldn't believe the bullshit they pulled.