Centrifuges

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GerryR
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Centrifuges

#1 Post by GerryR » Sun Aug 07, 2022 2:38 pm

I see some people use centrifuges, for example, to separate microbes in pond water. Are they merely a convenience or are they a "should have" piece of equipment for microscopy? Also, there are many options for centrifuges, variable speed vs. fixed speed, fixed angle rotor vs. variable-angle bucket rotor, refrigerated vs. non-refrigerated, different size tubes for the different size tube holders in rotors, expensive vs. inexpensive models. What RPM is good for fixed speed machines? Are 2 mL tubes sufficient for most specimen applications? Are the small, 4-6 tube rotor centrifuges that operate at a fixed RPM (4000-6000 RPM) any good? Just curious if I need to be looking at adding something else to expand my capabilities. Thanks in advance for any input.

Alexander
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Re: Centrifuges

#2 Post by Alexander » Sun Aug 07, 2022 2:53 pm

1. They are more a convenience than a should have.
2. A hobbyist will never need a refrigerated centrifuge.
3. Tube size and number of tubes depend on what you want to concentrate.
4. Variable-angle rotors are better than fixed-angle rotors but much more expensive.
5. A fixed speed centrifuge has very limited use value.
6. Speed alone says nothing. The power of a centrifuge is a function of speed and rotor diameter.
7. A variable speed centrifuge fitting 2 ml tubes will cover most needs for hobby microscopy. Look for a used Eppendorf Minispin. They come cheaper than a new Chinese one with similar specs and are much better.

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imkap
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Re: Centrifuges

#3 Post by imkap » Sun Aug 07, 2022 3:09 pm

Anyone tried a Dremelfuge?

Alexander
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Re: Centrifuges

#4 Post by Alexander » Sun Aug 07, 2022 7:30 pm

imkap wrote:
Sun Aug 07, 2022 3:09 pm
Anyone tried a Dremelfuge?
https://en.wikipedia.org/wiki/Centrifug ... al%20force.

Hobbyst46
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Re: Centrifuges

#5 Post by Hobbyst46 » Sun Aug 07, 2022 8:14 pm

imkap wrote:
Sun Aug 07, 2022 3:09 pm
Anyone tried a Dremelfuge?
The Dremelfuge sounds unsafe. If at all, I would only use it for really tiny tubes (<1ml liquid).
If one really needs a centrifuge (for diatom separation maybe, though not a must even there) a table centrifuge would be much safer.

And, for specimens for light microscopy, a relatively low power (speed times diameter as mentioned above) would suffice. Even a manual (hand-operated) centrifuge will do.

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imkap
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Re: Centrifuges

#6 Post by imkap » Sun Aug 07, 2022 8:52 pm

I never used a centrifuge so actually don't know how the result would look like. I have a salad dryer spinner, maybe that can be used? It turns at 800 rpm maybe... ;)
I don't really use it for salad so...

Here is the Dremelfuge:

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imkap
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Re: Centrifuges

#7 Post by imkap » Sun Aug 07, 2022 11:25 pm

Alexander wrote:
Sun Aug 07, 2022 7:30 pm
imkap wrote:
Sun Aug 07, 2022 3:09 pm
Anyone tried a Dremelfuge?
https://en.wikipedia.org/wiki/Centrifug ... al%20force.
Ok :D
I understand...

GerryR
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Re: Centrifuges

#8 Post by GerryR » Mon Aug 08, 2022 12:06 am

Well, is there some chart that one can use that tells what are appropriate RPM/g's for certain separation tasks?

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