Mini electric kiln project

[Jan]

Maybe we missed it somewhere in this thread Jan but what is the nature of the actual temperature sensor in your design? Thermocouple, thermistor etc.? Is it somehow built into your PID or is it some separate and remotely mounted analog device(s)? You realize, of course, that you have to be at least as old as we are to even know what an analog device is.

EOU, many PID controllers allow to use both, thermocouple or thermistor. I will use a K type thermocouple e.g. https://www.amazon.de/100mm-Spade-Thermo...uage=en_GB

What concerns analog devices, somewhere in the attic I have mercury thermometer which measures up to 650°C (1200°F).

The bricks were grooved and the elements were coiled. During the weekend I hope to post some images showing my progress.

Jan

[scott.livesey]

Thanks for the info Scott. Never dealt with anything with temperatures this high before. Our hat's off to thermocouple manufacturers for making a sensor capable of accurately responding to temperatures in this range without melting the temperature sensor. On naval guns; isn't that something? Heaving Chevy Novas 20 miles into somebody's backyard and not just any backyard...your backyard. We suppose that if the sea was calm they could have knocked the lid off your barbeque grill and all with just a slide rule and a couple of hand cranks.

gunfire control systems were much more sophisticated, they figured in curvature of the earth, where target would be, number of bags of powder, the wind, and most any thing else you could think of that would effect the flight of the shell.  the physics and math were known, it was combining all these elements using motor, gears and special potentiomoters.  you had/have variable resistors that scaled the signal that passed thru them in whatever way you wanted.  ie linear, exponential, logrythmic, or whatever you chose.  they did the same with gear trains.  it is the distance that amazes me.  in infantry combat, most things happen within 1000 yards.  in naval combat, 1000 yard is extreme close quarters.  

basic 'K' thermocouples are rated for 2300*F.  type 'R' are rated for 2700*F.

[EOU]

We're hijacking threads again so we apologise in advance to Jan but quickly here, so one bag of powder equaled how much additional distance Scott?

[scott.livesey]

6 110lb bags was max load and gave a range of 42,000 yards with a 2700 pound projectile which is about 5 feet long.

[Jan]

In rough terms, I have finished the construction part of my small electric kiln for one blade. The chamber is heated by six elements coiled on ceramic wire holders. I have used Kanthal A1 wire of 1 mm diameter. Max. operating temperature is 2550°F (1400°C).

The total installed power is 6 x 250 W = 1500 W. Our grid voltage is 240 V.

           

Now I am waiting for the ordered PID controller and thermocouple.

Jan

[scott.livesey]

does the controller include an SSR? most controllers just provide a small signal to turn other components, like SSRs or alarms, on or off.

[EOU]

Good gosh that looks nice Jan. If it works half as well as it looks it will be a huge success. Really, really nice job.

[Jan]

I have ordered the SSR separately because the controller I have ordered has either relay output: AC 250V, 3A or voltage output 12V DC, 30mA.

Mr. Scott I would like to ask you whether you use your furnace also for steel tempering.

Jan

[Jan]

Good gosh that looks nice Jan. If it works half as well as it looks it will be a huge success. Really, really nice job.

EOU, thanks again for your support. I am gathering psychic powers for the first turn on of the kiln.


Jan

[scott.livesey]

i use a toaster oven to temper. a brand new one was only $50US. works well as I don't temper over 400*F