The Physics of the Spin Speed

[bingwsguy]

Recent machines have an extended spin in the final spin portion of the cycle suggesting less residual moisture. While not a physics major, it seems logical to me that the faster the tub spins and the larger the tub is, the more water removed from the clothing by pure force. The longer it spins at the same RPM should have little, if any impact.
Anyone care to comment?

 

[DADoES]

I think more time does have an effect, even at a constant RPM, up to a point. A load being spun is a layer of multiple items so moisture must travel from inside to outside of the layer to exit through the basket perfs. I've noticed running a couple loads in the MiniBasket in Austin's FilterFlo that there were water drops coming out of it to the end of spin. Of course, given sufficient time at a constant speed, extraction will hit a maximum.

 

[Unimatic1140]

I spun towels out in the Super Unimatic at 1140rpm (with a clear glass window in the cabinet to see the water droplets coming out of the tub). I wondered how long it would take for the stream of water coming out of the towles to stop. After 30 minutes I gave up as water was still being removed from the towels.

 

[soapnsuds]

Hi Robert,

Cool! I'd love to see that on video!

Thanks-James

 

[frigilux]

My 2006 TL Frigidaire has a 12-minute final spin on the Whites cycle. Both the Colors and Delicates cycles have a 3-minute final spin time. While the maximum spin speed on the machine is relatively slow---I'm guessing it's around 500-525 rpm---there is noticeably less water left in the clothes after the long spin on the Whites cycle.

There is also a 20-second spray rinse near the beginning of the final spin, so on the Colors and Delicates cycles you're only getting about 2-1/2 minutes of spin time.

I often use my frontloader as an extractor after washing heavy cotton items (such as bath towels or loads of jeans) in the TL. Quite a bit more water is extracted at its 1000 rpm final spin speed, even after the TL'ers 12-minute spin.

I'd have to concur that a longer spin time removes a bit more water, but that the real bang-for-the-buck in that department comes from substantially increasing the rpms.

 

[panthera]

its not how fast you do it (alone) but how you do it

Several years back, when the 1200 RPM machines were only just becoming affordable, Stiftung Warentest (like Consumer Reports used to be only even more deadly dull) was very surprised to discover that several AEGs running at only 750-900 rpm had equal or better water extraction when compared to the 1200rpm machines.
The way the spin cycle is set up has a big influence on how well water is extracted. A few years later, AEGs running at 1200rpm but still using the excellent spin set-up, vastly outdid all the other machines running at the same speed.
Sure, the higher the speed, the better the extraction. But you have to give that higher speed the time and the well balanced load to do its work. I wouldn't trust a machine to really spin clothes drier just because it has a theoretical top speed of 1200rpm+. Look at the modern junk Bauknecht is putting out and compare it to Miele or B/S/H or Electrolux spinning at the same speed. Big difference in extraction.

 

[lederstiefel1]

Bauknecht junk

Bauknecht was once a very reliable company until Whirlpool took them over......

Ralf

 

[toggleswitch]

Let us also not forget that the diameter of the spinner influences the efficiency of extraction.

Given the same spin-speed a larger tub will generate greater G-force and extract better.

A simple way to demonstrate this is a mini-basket in a GE Filter-flo, which spins at the same speed as the full-sized tub. Mini-basket items tend to stay nearly dripping wet even after a long spin.

 

[toggleswitch]

~Bauknecht was once a very reliable company until Whirlpool took them over......

So was Maytag.

 

[johnb300m]

Maytag screwed themselves. Ironically, Whirlpool will be a needed improvement from independant Maytag.

 

[jetcone]

Actually there are 4 things affecting Extraction

So everybody has part of the story.
1) One is the tub diameter , a larger diameter and lower speed will produce the same amount of "g' force as a small tub with a higher spin speed.
2) Spin Speed
3) Duration as Robert's experiment proved. There would come a point where the extraction would drop to ZERO but then at the speed he's wailing things around you would start to dry the clothes due to evaporation of the air mass swirling around
4) the forth element is the electrostatic attraction a water molecule has to the fiber it is attached too. Eventually only evaporation will remove this no matter how long you spin or how fast.
Actually there maybe a 5th, the hole size like Glenn mentioned, giving access to the water leaving the tub.
So machines can come in all kinds of configurations to produce a certain g force.
I always wanted to build a top loader spinner that sealed up at the end and turned on a microwave to heat the clothes while spinning and see just how dry they got then!! That would be a cool experiment to try!!

 

[soapnsuds]

Hi Jetcone,

~~1) One is the tub diameter , a larger diameter and lower speed will produce the same amount of "g' force as a small tub with a higher spin speed.~~~

So what does this mean exactly? That my Asko which spins at 1600 RPM's extracts the same amount of water as my LG which tops out at 1100 RPM's?

What about the weight or size of the load? Does a full load of towels help with the spin and extract more water because there is more weight or does it hurt because there are more layers for the water to go through before it leaves the tub?

And while we're at it, how DOES a solid tub washer extract water without holes? I realize that in the begining the water is thrown over the top, but after a certain point, there isn't anymore to throw over...seems to me, when the cycle is done, you'd be left with a wall of water on the inside of the tub.

These are the burning questions of the day!!

Thanks--James

 

[jetcone]

Welllll!

Let me get back to you later, I must walk AL now its HIS time!

Jon

 

[roto204]

Squidge factor

Part of the reason a solid tub works is that there actually are holes tucked up under the top lip of the tub.

That notwithstanding, when you accelerate the tub, the water flattens out to cover the surface area to which it's "squished." Since water is a liquid and tries to take the shape of its container, it flattens continually until it squirts out the holes at the top, or flies up over the top edge of the tub.

That's why there isn't any water to speak of left after a solid-tub spin. If the spin were perfectly balanced, slow, and the tub was mostly closed, like a doughnut, then I could see where you'd just end up with a ring of water on the inside. But the design of the tub and the physics at hand take care of business

 

[chestermikeuk]

Perfs

The fifth is not the hole size but the configuration of water leaving the tub...The UK Servis Quartz Front Loaders of the late 70`s had a "SpinCare" drum, no holes just a bevelled drum with a channel at the back , front & Middle, so the water was channeled to the vanes and extracted...

Most uk manufacturers used to advise no more than 4 mins for max extract of cottons from a twinny spinner running at 2,800 / 3,100 rpm..

We also had a "Thermair" spinner in the 60`s that had a heater on top situated in the lid, and blowed warm air down onto the clothes...was popular but didnt last long, if you didnt shake out the clothes before heating they would crease badly from being plastered against the side etc...innovative though...

Mike

 

[toggleswitch]

~That my Asko which spins at 1600 RPM's extracts the same amount of water as my LG which tops out at 1100 RPM's?

Assuming the Asko's cylinder is 22" in diameter to fit in a 24" cabinet, and that the LG's cylinder is 25" in diameter to fit in 27" cabinet, then: both spinning at 1,100 RPMs would make the LG more effective. It is possible that at 1,600 rpm the Asko is extracting the same or slightly more (but not a lot more) than the LG due to the Asko's smaller cylinder.

Let's put it this way, Euro washers must spin fater than American ones to extract the same amount of water. Sometimes bigger IS better. Euro dryers have 2,500w +/- heaters (plug-and-play into any power-point) whereas American dryers have 5,000w heaters (special 30a 220v circuit). Again this demands greater extraction ont he part of Euro washers as well. Excessive extraction, however, can be said to tear fibers in the clothing and to cause excessive creasing / wrinkling in and of itself.

Please note, I did not say or imply one system is better than or preferred to the other.

 

[panthera]

bigger is always better,

And the only two US appliances I miss in Europe are dryers and refrigerators.
I've spin dried stuff at 2,800 for over 24 years now...never lost anything into near-earth-orbit yet...but also never ran longer than five minutes.
At 1200-1800 rpm, absolutely no chance of tearing or permanent wrinkling...else they would not be accepted by the testing societies here in Europe or the very clothes conscious.
I adore the way you tip-toed around the split-phase current. Actually, the UK no longer has 240V...they only have 230V now like the rest of us...

 

[bingwsguy]

Thanks Everyone

Keven, you brought out another question. The "How you do it" comment made me wonder if the machine picking up speed slowly vs. taking off & going right up to full speed has any effect on extraction?

Mike and Nate you answered questions I had about the size of the holes in the tub....and for that matter none at all. I was under the impression that the more holes, the more water would escape. When Miele came out with the Honeycomb Drum with more surface area and less holes...I wondered about that, but figured if they developed it it must work. I still have questions on the Honeycomb Drum...another thread...

Steve and Robert, thanks for the real-life test feedback on drum size and time...I assumed the size would make a difference, but not the length of time at constant speed.

 

[soapnsuds]

Yes, thank you everyone for all the help!

~~Toggleswitch
~Euro dryers have 2,500w +/- heaters (plug-and-play into any power-point) whereas American dryers have 5,000w heaters (special 30a 220v circuit).

What do you mean "plug-and-play?" My ASKO has a 240 volt plug,(and then the washer plugs into the back of the dryer) you mean it's not the same size heater as my LG? I know its probably a bit smaller, because the dryer only has to heat settings, low and normal. And when I read the brochure after I got them the ASKO said that the dryer differed slightly then and american one because Europeans believed in lower heat drying for longer time vs. higher heat for shorter times. Gentler on the fabrics they said. I say higher on the old electric bill. Since I have to heat the hot water in the machine AND dry the towels forever in the dryer. Is there really that small of a heater in the ASKO vs the LG?

As always, thanks for the time and help!! -James