Heating element

Projects General Guidance
1

Hi Folks,

Currently I'm switching a 100w heating pad with a 5v, 10A solid state relay. I'm triggering it with a Sharp IR sensor. Currently the heating pad is taking about a minute and a half to reach maximum temperature. For me that is taking too long. I'm wondering is there a way that I can get the heating element to heat quicker? Is there something I can do to achieve this. All help on this is very welcome.

Thanks folks

2

What is the voltage supplying the heating pad. To get it to heat faster you need to increase the current. Since you can't change the resistance the only way to increase current is to increase voltage (Ohm's law). You must also stay within the specs of the heating pad in terms of maximum current.

3

Thanks Groundfungus,

It's says on the plug of the heating pad that 3A/250v.

4

Please post a link to the product page or data sheet for the heating pad.

5

What are you heating with the pad? Are you needing to heat both sides of the pad? If not, add a reflective insulation to the side not needing the heat.

Paul

6

Hi Folks,

Here's a link to the heating pad, http://www.sanitas-online.de/web/en/products/heat/heating_pads/heating_pads/SHK-18---Heizkissen

Basically, I'm looking to heat paper with Thermochromic ink on it. The ink reaction threshold of 27 degrees celsius.

Currently I have thermal adhesive on the heating pad to stick the paper to it, with the cover taken off the heating pad to get maximum heat.

Thanks folks

7

No I don't need both sides, just one side for the page with thermo ink to sit on.

8

Hi,

Those heating pads are designed to heat humans, and being only 100W it get up to temperature relatively slowly.

You would need a higher power heater pad that that one.

If you are only looking to get to 27C or so, and you go for a higher wattage heater, you will need to keep the thermal mass of the assembly down and include some temperature feedback to a controller to make sure it functions correctly.

How quickly do you want the heater surface to get up to temp, and how long to drop back so you can reload the paper?

I don't know if a 3D printer, heated base would do the job, they may be slow as well.

Tom.... :slight_smile:

9

Hi Tom,

Thanks for your feedback on this. Ideally I'd like the heat pad to come on within about 10 seconds-20 seconds, the quicker the better and if I could it would be great to get the paper to drop back to it's original state as quick as possible. Are you suggesting a temperature sensor? I'm not sure exactly how this would work.

Again thanks for your help on this

Liam