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Making a temperature regulator

I've got several things I'd like to regulate. A heat treating oven
we have so that would need to go to at least 1800 degrees with
regulation of plus or minus 25 degrees.
Then an incubator for hatching duck eggs. This needs to be plus or
minus 1 degree.
What I don't know is what devices to use for the sensing. I really
need some article or book on the subject. I took electronics for 2
years about 10 years ago buy have almost no experience since then in
it.
 
W

w2aew

Jan 1, 1970
0
There are a lot of options for temperature sensing - everything from PN
junctions (diode voltage), to various IC sensors, to thermocouples,
RTDs, thermistors, etc. What you choose will highly depend on the
application.

There's a pretty good technical reference on Omega Engineering's
website:
http://www.omega.com/techref/
 
C

Chris

Jan 1, 1970
0
I've got several things I'd like to regulate. A heat treating oven
we have so that would need to go to at least 1800 degrees with
regulation of plus or minus 25 degrees.
Then an incubator for hatching duck eggs. This needs to be plus or
minus 1 degree.
What I don't know is what devices to use for the sensing. I really
need some article or book on the subject. I took electronics for 2
years about 10 years ago buy have almost no experience since then in
it.

For sensing high temperatures, you'll need a thermocouple. Depending
on the peak expected temperature, you could either use a K-type
thermocouple, or one of the more esoteric higher temp ones, like an
R-type T/C. These are good for fairly precise sensing of temperatures
in this range.

For very precise sensing of low temperatures (30-40C) your best bet is
an RTD (Resistive Temperature Device). This will give you accuracy of
within a couple of tenths of a degree.

For either of the two applications, you'll need something called a
temperature controller. This is a programmable device which accepts
the sensor input, and has an output which controls the heat treating
furnace or the incubator.

Also, your heat treating furnace will probably need a ramp-soak
feature, which makes the furnace temp rise at a timed, set rate to go
from one temp to a second higher one (ramp), then maintains that temp
for another set period of time (soak).

A good one-stop source of information on temperature control is the
Omega Engineering Temperature Handbook. Not only is there a lot of
technical information, but also a wide variety of products available
which will do the job for you. Best of all, the Temperature catalog is
free. That's free, as in beer. Don't believe it, take a look:

http://www.omega.com/

Click "Free Literature" on the menu bar at the top of the webpage, then
select Omega Product Handbooks (the Temperature handbook is the thick
red one).

A lot of the technical information is available in abbreviated form on
the website. Just click around and have fun.

Good luck
Chris
 
J

Jasen Betts

Jan 1, 1970
0
I've got several things I'd like to regulate. A heat treating oven
we have so that would need to go to at least 1800 degrees with
regulation of plus or minus 25 degrees.

for the kiln a thermocouple is probably the way to go
Then an incubator for hatching duck eggs. This needs to be plus or
minus 1 degree.

for temps below boiling point there are semiconductor sensors like LM335
that give a nice simple voltage output.
What I don't know is what devices to use for the sensing. I really
need some article or book on the subject. I took electronics for 2
years about 10 years ago buy have almost no experience since then in
it.

feed the output into a comparator that also sees a correclty adjusted
reference volttage and then into whhatever control device you want to use...
(optocoupler to a triac, or a transistor to drive a relay.)

you'll probably be wanting a fan in that incubator to keep the temperature
even.


Bye.
Jasen
 
I've sent off for that free info from Omega and it should be a start
to this. I liked that idea for the heat treat oven of having it so
goes from one temp to another. That would really help
Ken
 
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