DIY Refrigerated Centrifuge

[Kavish Sirisena]

Greetings fellow researchers! 

I am in need of a refrigerated centrifuge to process some proteins samples extracted from a mammalian cell line. The lab that I currently work does not have a refrigerated centrifuge to accommodate this. Is there any other alternative way to reduce the temperature of the working conditions?

I was thinkin maybe I could suspend a small eppendorf tube inside a bigger tube filled with water and subject it to freezing. However I am not sure how this would affect the centrifugation procedure.

Looking for your valued opinions on this matter!

TIA

Kavish
IRD Genetics - Sri Lanka

[djwr...@gmail.com]

I throw mine inside the refrigerator the night before and run it inside.

Sent from my iPhone

On Oct 22, 2022, at 8:40 PM, Kavish Sirisena <kavish....@gmail.com> wrote:

Greetings fellow researchers! 

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[S James Parsons Jr]

Would you be able to get a sacrificial refrigerator and move your centrifuge into it?

On Oct 23, 2022, at 4:15 AM, djwr...@gmail.com wrote:

I throw mine inside the refrigerator the night before and run it inside.

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[Jonathan Ferooz]

Putting the centrifuge in a cool bag with cool pack? Or just putting the rotor in a fridge before?

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[Dan Kolis]

How long is the run in minutes ? What's the temperature and tolerance and volumes of each unit sample, how many etc. how many G ? Are the materials hazards ? ( ex normalize to a BSL-X risk ).

Is it a multi day, week month or ongoing requirement in your best estimation ?

Answering the question(s) before there asked enables answers before there composed...

Much more detail enables better answers and stories of direct experiences....

Regards,

Daniel B. Kolis

[Dan Kolis]

Ive had complete success with Peltier fixtures. this $5 semi moves 8 W and has a 8 by 15 mm face...

KW: Thermoelectric Cooler Peltier TES1-03102 TES1-03103 03104 mini 15*15mm low power 3V2A high efficiency Peltier on ali baba but that search will find it in the product pipeline better for your situation, probably.

If its an ONGOING requirement a fixture with a 9 V battery 555 timer and this would make it stand alone entirely from other open issues for temp.

Until the batteries dead, that is ... Low duty cycle is required so the thing lasts awhile... its all about delta T and thermal resistance, little dissappation material aka 'fin'.

Example idea...

[Marc Juul]

Do be careful if deciding to cool the entire centrifuge. The centrifuges that have built-in cooling generally have at least some of the electronics encased in conformal coating to prevent issues with condensation. The small tabletop centrifuges I've taken apart don't have this feature. If your lab happens to have a dry air source (e.g. for IR spectrometry) then you could maybe do something with that to prevent condensation. If you are cooling the centrifuge itself then you likely want to add condensation protection and I don't recommend manually adding conformal coating to the circuit boards without also adding extra cooling for the mosfets since the mosfets in the three-phase inverter dissipate enough power that overheating is a common failure mode in the medium format eppendorf refrigerated centrifuges even though those are strapped to a block of aluminum which is then strapped to the thick steel case of the centrifuge chamber. Normally I'd be gung ho about people hacking their gear and seeing what breaks but I assume you don't want to risk killing your centrifuge with the difficulty of importing stuff into Sri Lanka right now.

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[bioscisam]

I did try this, rather than refrigerating the whole centrifuge just refrigerating the removable carousell (big lump of metal) , OK for a few short spins but the machine quickly heats it up. Some setups might allow you to add ice or dry ice to the tube carrier (obvs. be careful with dry ice and not popping gas tight things).

[John Griessen]

On 10/23/22 10:26, Dan Kolis wrote:
> Ive had complete success with Peltier fixtures. this $5 semi moves 8 W and has a 8 by 15 mm face...

What was it like balancing the weight and attaching wires so they don't move on a centrifuge rotor?
The 9V battery seems large for centrifuges we usually think of. Are you using an old school centrifuge for 50 ml vials?

[Dan Kolis]

I used Pelitier coolers for fuel systems, not life science wet lab. the Peltier 3 layer stack was pinned to a manifold which ran perhaps at a duty cycle of 50% with maybe 0.3 G of vibration continuously. As in nominally expected to run perhaps 3 years without maintenance.. This chilled Methane maybe down 45 C. Note Pelitier cooling versus expended power is very quirky.  Unlike compression chilling, its weirdly non-linear, when lightly loaded versus cell capacity, its efficient and worsens as it achieves higher loading... ex a multi layer stack will do a better job at fixed dissipation then a less or singular stack... just because the one considered is a area of a postage stamp, the same thermodynamics apply...

I see some alum or perhaps some better allow test tube holders and assoc charging stations. Creating a center of gravity for a load is by definition pretty simple.. 

Yet, actually creating anything repeatability usable is a non trivial process of trial and error. Obviously, the best way to achieve the goal a few times is go someplace else with the 'right' equipment and ... the goal is achieved.

But *if* it is easy to visualize the requirement is ongoing, especially if other temperature management requirements are achieved; ( handling simplified, lower RMS of unwanted delta T deviations, etc. ) It might be worth considering.

Managing temperature is a very very common industry requirement. Omage has a catalog the weight of a hand brick and a half with thousands of doo dads to do these things...

https://www.omega.ca/en/

50 ml seems a convenient mass to consider chilling with a rechargeable aka 'battery' one of fixture... 

ther unwanted wiggle in the centrifuge is Omega V^2 so again the question of the reasonableness or not of the notion involves extreme specification of the goals, delta T's and G's, how long the new temp must be maintained, etc....

Also, if for instance the device is rechargable on a USB 5 V port probably it can squirt back the temperature encountered. That is, instead of being an improvisation, such a device can be a normalizing aspect of utility in the science of the process itself, possibly...

Regards,

Daniel B. Kolis

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[Kavish Sirisena]

Hi everyone!

Thank you very much for all your valuable inputs! Helped me so much!

With best regards,

Kavish Sirisena
IRD Genetics Sri Lanka

[Dan Kolis]

 https://joeraut.com/posts/peltier-mini-fridge/

Pelitier is commonly dismissed by HVAC ( Heating ventilating Air Con ) guys as too inefficient to compete iwth gas compression for cooling. However two things:

Coupling the semi to the load matters immensely. You can heat or cool a thermal interface and measure the temp with a themocouple and figure the thermal resistance in W/cm^2 or mm^2 etc.

So you can work with HEAT more easily, then just multiple by -1 * and design the cooling variation. Of course, just turn the voltage around the cooler heats, anyway...

So, yowling the semi is not doing enough starts with how your load gets to free air. If its lossy, thats a place to fix it. TRY COPPER NOT ALUMINUM, etc dabs of conductive goop, etc.

Also, Peltier is unusually sensitive for efficiency to % of max load. if you only use it to 10% of its designed max, its far more efficient then 80%. So *if* you want efficiency ( rare in a lab, but possible ) OVERSIZE the part and run it at a smallish percentage.

For variable temp at high precision, use PID thinking, that is approach the final temp with a duty cycle that changes of a variable part like a 555 timer of better yet a ARDINO or other few component Single board computer postage stamp part.

If the load and ambient temp is known a variable resistor or time chip is probably ok for a tolerance of +- 2 C. 

Even if you make a self controlled, closed loop you have to calibrate it occasionally before you can trust it. So really,, a simple control approach is probably ok, you should have independent temp measurements anyway for any serious work.

The URL above shows a DIY approach for a cooler.

Regs

Daniel B. Kolis