Peltier as element as a heating elemen /O ring silicon gasket

Thread Starter

Kadav

Joined May 11, 2018
148
Hello, i am working on a project and i have 3 important questions to ask, if you can help me

1) can I use Peltier element as a heating element (because it normally works as a cooling element), if yes how please in a brief way

2) can i use O ring silicon gasket as a heating element ... i am seeing them but i don't know how they can be used as heater, if they can be connected to 12V battery and wiring them, or how they can be connected.

3) I am using a 100 mm rounded sort of dish, and i need a heater that is rounded, what is an idea can you give me.

Thank you very much

figure Below is a Peltier element present on a petri dish
1592271555601.png

Figure below shows silicone O ring

1592271944794.png

Thank you very much...
 

dendad

Joined Feb 20, 2016
3,721
You could use a Peltier device as a heater, but why not just use some resistors, or a power transistor?

The silicone O ring is not a heater. the "silicone heaters" that are available have a heating element in them, and use the silicone as a flexible electrical insulation.
What form the heater element is can vary. But a standard silicone O ring will be an electrical insulator.

A round Aluminum holder that fits the glass dish can have some power resistors and a temperature sensor attached to it, and the Aluminum will spread the heat evenly, as well as being a "flywheel" to help keep the temperature more stable.
Also, a circuit board with long tracks etched on it can work as the heater. 3D printers often use this as the bed heater, but I would go with a couple of power resistors bolted to the Aluminum plate.
 
Last edited:

Thread Starter

Kadav

Joined May 11, 2018
148
You could use a Peltier device as a heater, but why not just use some resistors, or a power transistor?

The silicone O ring is not a heater. the "silicone heaters" that are available have a heating element in them, and use the silicone as a flexible electrical insulation.
What form the heater element is can vary. But a standard silicone O ring will be an electrical insulator.
Thank you. Very much

Can you please explain me how to use a resistor and power transistor as heating element,I don’t understand
 

dendad

Joined Feb 20, 2016
3,721
power resistor.jpgpower resistor1.jpg
Bolt a couple of these (of suitable value) onto the plate, and power them through a temperature controller...

TempController.jpg
Run it all off 12V.
The resistor values will depend on the temperature you need.
These pictures are from Ebay.
 

dendad

Joined Feb 20, 2016
3,721
Off course, if you need heating and cooling, the Peltier can be used. It will need the other side having a heat sink and fan, then a controller driving an H bridge so the power to the Peltier can be reversed.
It would be a good Arduino project.
Have you looked at Arduinos?
 

Thread Starter

Kadav

Joined May 11, 2018
148
Off course, if you need heating and cooling, the Peltier can be used. It will need the other side having a heat sink and fan, then a controller driving an H bridge so the power to the Peltier can be reversed.
It would be a good Arduino project.
Have you looked at Arduinos?
Yeah I’m. Actually working with Arduino , right now.
But yeah. That would be fantastic...

So you mean that I. Can use Peltier as big a heater and a cooler using an H bridge in order to reverse the power of Peltier..
 

dendad

Joined Feb 20, 2016
3,721
So you mean that I. Can use Peltier as big a heater and a cooler using an H bridge in order to reverse the power of Peltier..
Yes, within the power limits of the device.
Have you played with H bridges and PWM (Pulse Width Modulation)?

You would not need PWM actually.
Just a couple of SPDT relays driven from the Arduino, with the Peltier connected in the H bridge configuration. One relay would heat, the other cool.
Neither or both would be off.

ArduinoDualRelay.jpg
DualRelayHBridge.png
"M" = the Peltier in this case. This is just a picture a quick search found.
 

dendad

Joined Feb 20, 2016
3,721
Another way is to use the 2 relays, or just one DPDT relay to set the heat or cool, and a power FET driven by PWM to give fine control.
A 3D printer MOSFET board would work very well if you do not want to make your own.
MOSFET.jpg
 

Thread Starter

Kadav

Joined May 11, 2018
148
Hello

Can anyone tell me if you know how to find a small heater that can heat up to about 37 deg , that is through hole or O ring maybe , that can allow light to pass through .
I am trying to design it for my project but i can not find a way of looking for it online
Thank you..

1592389381585.png
 

MisterBill2

Joined Jan 23, 2018
7,976
Better to give all the details of your project so we can see the limitations that you don't.
The details need to include how evenly the heat needs to be and how accurately the temperature must be controlled. Also how fast the heat must raise the temperature. Power and weight limitations will have an effect, as well as any size constraints. and passing light through may mean being able to see through the heater clearly, or to just allow illumination, which is a lot different. And the allowable total cost will also have a large effect on the design.
My initial suggestion would be an array of very thin nichrome wire, perhaps#30, held in place by a fairly clear adhesive able to stand that heat, such as some types of silicone. The heater could be in a sandwich of clear glass for support and protection. Temperature sensing could be done with a few RTD sensing material strands embedded in the same structure. This is a first-guess suggestion based on almost no information, so it may not work for your application.
 

Thread Starter

Kadav

Joined May 11, 2018
148
The details need to include how evenly the heat needs to be and how accurately the temperature must be controlled. Also how fast the heat must raise the temperature. Power and weight limitations will have an effect, as well as any size constraints. and passing light through may mean being able to see through the heater clearly, or to just allow illumination, which is a lot different. And the allowable total cost will also have a large effect on the design.
My initial suggestion would be an array of very thin nichrome wire, perhaps#30, held in place by a fairly clear adhesive able to stand that heat, such as some types of silicone. The heater could be in a sandwich of clear glass for support and protection. Temperature sensing could be done with a few RTD sensing material strands embedded in the same structure. This is a first-guess suggestion based on almost no information, so it may not work for your application.
Oooh Ok thank you very much, I thaught that was enough information but im sorry



So the specification of my project is to heat a petri dish that is made up of some nano samples ,



  • The temperature needed is 37 deg -39 deg roughly
  • Temperature rise time ofcourse the fast it could be the better
  • Passing light means just to allow illumination to pass through
  • Allowable cost in range 0f $30-$100
  • Current might be a 3A max


If there is something missing im willing to give it out.. Thanks
 

ElectricSpidey

Joined Dec 2, 2017
1,458
I would use the resistors mounted to an aluminum heat spreader for the heat, and above that I would use a piece of thick buffed acrylic with side LED lighting.

In fact you might skip the aluminum and use the acrylic as the spreader.
 

Thread Starter

Kadav

Joined May 11, 2018
148
Another way is to use the 2 relays, or just one DPDT relay to set the heat or cool, and a power FET driven by PWM to give fine control.
A 3D printer MOSFET board would work very well if you do not want to make your own.
View attachment 209857
Hello thank you for your advice on the H brige circuit , I actually have been trying to build one since morning . but I faced a problem


I am using proteus simulation, and I am using power MOSFET , but I realise that the switch at the NPN transistor is useless compared to the one at the LED.. can you please explain me why ??

Thank you very much ….
1592415709822.png
1592415770264.png
 

Thread Starter

Kadav

Joined May 11, 2018
148
Hello thank you for your advice on the H brige circuit , I actually have been trying to build one since morning . but I faced a problem


I am using proteus simulation, and I am using power MOSFET , but I realise that the switch at the NPN transistor is useless compared to the one at the LED.. can you please explain me why ??

Thank you very much ….
View attachment 210005
View attachment 210006
And its only with MOSFET but Transistors BJT its not the same .. can you please tell me

ALso can you tell me in some simple ways the difference betweeen transistor and MOSFET ?
 

Thread Starter

Kadav

Joined May 11, 2018
148
Hello i am trying to build a heating element , that may have almost equal physical properties to this one in the image below
1592573785402.png
I would love to heat the petri dish that is enclosed in the box , but ofcaurse i dont have the equipement ,so i would love to use general Electronics equipement that are out there

the petri dish is again 100 mm diameter , temp is 35 deg (so a light heating equipement would serve well .)

what advice can you give me.. t

Thanks
 
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