What's the Best Way to Heat Stainless Steel Tubing?

There are nearly endless possibilities to heat stainless tubing, choosing the best one is completely reliant upon your specific application which you have given no information on. 350° C is fairly warm, is this for an industrial process? or some kind of DIY project?

It is for a continuous chemical process. I want to find the best way to heat the tube in which the chemical will flow. By best I'm considering cost effective. I also want to do some heat exchanging in the design. I don't know what is a DIY project, my first language is french I'm from québec city, so!

google "electric band heater" these are designed for you application

http://www.tempco.com/band/band_heater_hub.htm

Wrap with high-temp electrical insulation. Spiral wind with Ni-Cr heating wire (generally good up to 1000°C). Cover with thermal insulator.

You need to do some sums about how much heat the stuff in the tube will carry away, so you can work out how much power you need to put in, & hence calculate the wire length & gauge and the power supply requirements.

Can you suggest where I can buy those things?

Just FYI (For your Information) DIY is an acronym for "Do It Yourself"

Sorry I'm not more help.

Here's a company (from among many) that can supply the wire.

As a mod to my original suggestion, you could use high-temperature fiberglass sleeving over the wire (which would also insulate adjacent coils), and lag the whole thing with fiberglass tape or wadding. Wind the heater evenly to avoid hot-spots. We made a similar heater using a glass tube, with a spiral grove ground in it to guide the wire. This was a one-off for a lab set-up - it cost a small fortune (rich customer).

Maybe you could use an additional winding of sleeving between the turns of heater wire to space it out.

You'll probably have to do some sums based on the heating figures in the first link, then do some experimenting.

If your product throughput is very variable (so the rate of heat loss will vary) or if you need tight temperature control, you'll probably need to embed a temperature sensor in the coil (thermocouple or platinum resistance thermometer element), and use a PID controller to get the temperature right. Use thin-walled SS tube if you need fast response.

(BTW - it occurs to me that this kind of in-line process heater must already be used commercially - have you tried searching for a ready-made solution?)

Good luck,

John

IMPORTANT!

The first link I posted (heatersplus.com) describes using the wire with mains voltages - I'd strongly advise you to keep the voltage down to, say, 24Vac (or whatever your local regs allow).