Anusha,

What volume of milk are you trying to warm?

And how rapidly do you want to warm it from one point to another?

(I'd look at thermostatic stirrers

https://www.amazon.ca/SCILOGEX-Scilogex-86143101-MS-H280-Pro-Circular-Top/dp/B00AYGIFCA/ref=asc_df_B00AYGIFCA/?tag=googleshopc0c-20&linkCode=df0&hvadid=292942668188&hvpos=1o2&hvnetw=g&hvrand=6848115299196788466&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9001529&hvtargid=pla-384726217145&psc=1

And insulate the beaker well)

I would like to heat very less amount of milk(from 5ml to 10ml)

And want a small device for heating

like if you see the size of W1209 digita temperature controller, that much size heaters will be helpful for my scenario.

Kindly tell me if know any heaters which are available similar to that

thanks for your suggestion.

James Garry

Anusha,

Ah, that's interesting.

The controller that you have is quite well-suited to the task. I tend to prefer industrial 'DIN' controllers such as the CAL9000

( https://www.ebay.com/c/662477745 )

But you've got something very similar with the W1209, although with less variety for the type of temperature sensor (RTD only).

The principal difficulty will be in ensuring that the volume of milk has a uniform temperature. The second challenge will (as always) be in getting good thermal contact between your heater and the vessel that holds the milk.

Here are some ideas:

1) I am inclined to acquire a short section of thin-walled copper tubing, cap it off with a disc of copper and some solder, and use that as the vessel - copper preferred for its high thermal conductivity

2) For getting heat into the copper efficiently, consider using an off-the-shelf Kapton heater foil. They are flexible, come in a variety of resistances, and insulate the electrical circuit from the vessel that holds the milk.

3) To sense the temperature, you can either stick the RTD (such as this:

https://www.sensorsci.com/small-bead-thermistors ) to the copper vessel (epoxy) or have it dangling in the milk. Attaching the sensor to the vessel will ensure that you never over-heat the milk, but means that the milk will take a while to equilibrate with the vessel.

4) If time is an issue, you might want to stir the milk. A pager motor and a slightly bent wire can make a tiny stirring 'engine'.

5) If thin-film Kapton heaters are not available in a timely manner (Omega, Minco, Auxiplast all make them)

eg

https://www.minco.com/products/heat/polyimidethermofoilheaters

(eBay might have some at reasonable price!)

...then you may want to fabricate your own. You'll need to first wrap a thin insulating sheet around the copper vessel. I would use a Kapton or fibreglass tape:

https://www.amazon.ca/High-Temperature-Resistant-Kapton-polyimide/dp/B00DIV24DY

Then, carefully, wind the nichrome around the vessel, and tightly wrap the nichrome with another layer of tape - sandwiching the nichrome between the layers of tape.

For extra security, before you put on the second tape layer, a thin smear of epoxy on the nichrome won't do any harm - just to immobilize the wire.

Then, having done all that, insulate the heck out of the copper tube - an inch of fibreglass in all directions should suffice. Or a cylindrical hole in a slab of foam - with a matching foam cap. I'd avoid polystyrene - 60degC sounds rather close to its melting point.

A polyisocyanurate would be ideal - or even a thick blanket of wool or felt would be better than nothing.

If you're winding the nichrome, a simple heat balance model will tell you what length, diameter, and voltage you'll need to achieve a given warming rate. I might have a spreadsheet for that at work... will let you know.

I'm sure that you appreciate that the thermal controller will be switching a power supply of some sort (DC, and I'd use a solid-state relay for simplicity), so budget for that.

Thank You James.

Its a great suggestion.@James Garry

Anusha Phyrdha Feel free to ask for clarification.

I've had to heat tiny things before in odd situations.

In this vacuum chamber (about 20 years ago)...

http://www.bipbip.info/jg/make4.html

... I had to warm about 2grammes of various amino acid crystals, fairly carefully - and measure the temperature while doing so.

Sure James. Definitely

I am just in my starting stage. So happy to take any suggestions and clarifications from people like you.

Thank You.

James Garry