Thermocouples.

[graffian]

You need to look for a pid that isn't limited to 400C.
I bought one for a heat treatment oven, I got similar to a the one linked to but without the 400c max.
No idea of it's make, it's a typical cheapo pid I will have a look tomorrow if I remember.

 

[graffian]

I just looked through my pdfs and found a pdf for a MYPIN TA4, seems to have a range that includes K: 0~999/0~1200[why the two ranges?] and S: 0~1600.

 

[tinman123]

i had to google it there as i couldnt remember all the types of tc's the my-pin can take but its K J E S PT100 & CU50.
afaik the K type is only good up to 1200dgs c odd, its been about for a while now and newer tech is available now so thats probably why the S is higher.
i didnt see anywhere two ranges for a K type tho or the mention of 999dgs either, whats up there or have i read you wrong.

this might be of some help to someone, ive only watched about 15mins of this but this lad seems to know his stuff on them, the sound is a bit off and there is a bit of babble but if he keeps going the way he has it might prove informative for someone.
they do provide an instruction page with them but its tricky.

 

[daleyd]

afaik the K type is only good up to 1200dgs c odd, its been about for a while now and newer tech is available now so thats probably why the S is higher.
i didnt see anywhere two ran

S type is just different metals - k type is used because it's cheap and does a fine job for 90 odd % of applications. S type is platinum rhodium, more expensive (which is why they are not as widely used as k type) but goes to higher temps. S type are used extensively in the glass industry because they can be gas welded directly on to platinum alloy tubes and metalwork used in glass manufacture. (They are also used in lots of other industries where higher operating temps are needed)

 

[norlander]

Get a life, gob on it, if it skids off its hot enough, if it don't it aint.

 

[norlander]

Get a life, gob on it, if it skids off its hot enough, if it don't it aint.

 

[RustyBus]

Erm... 1.8v rings a bell with me for the BBC analogue port rather than 5v. The analogue port has 4 channels, if you only have 1 input then use channel 0 and switch the others off and it speeds up the conversion, I still play with my old 8 bit Acorn kit from time to time

Here's a schematic if that helps? Also a closeup of the paddle port, yes that's 3 forward biased diodes for the ref voltage!
Hope that helps
Rusty.

 

[bigegg]

I have the exact same schematic somewhere, as well as the Owen bishop (?) book on interfacing the beeb

 

[RustyBus]

It's rather sad that's it on the book shelf behind me here!

 

[bigegg]

Pid kit arrived today.
Quick play reveals it can be set to a trigger temp of 999deg C - only got the thermocouple to 300c on the electric hob so far tho...

 

[tinman123]

mapp gas and a superfire head will bring it up for you.

if you dont have one, they are handy, i do silver solder with the one i have, that and about 100 other uses for it, i wouldnt be without it.

 

[bigegg]

mapp gas and a superfire head will bring it up for you.

if you dont have one, they are handy, i do silver solder with the one i have, that and about 100 other uses for it, i wouldnt be without it.

Funnily enough, I just bought a sievert torch at the weekend - trouble is, my regulator is buried in the shed pending me unpacking from my house move.

 

[rosinante]

S type tc is made from 99.9 platinum on 1 wire the other is 90pc platinum and 10 pc rhodium.
The ones we used were duplex and contained 14 g ,at approx scrap value £20 a gram,type r and t similar, all insulation on them was ceramic, of course they were all returned when changed
Chris

 

[tinman123]

Funnily enough, I just bought a sievert torch at the weekend - trouble is, my regulator is buried in the shed pending me unpacking from my house move.

the propane isnt far behind the mapp, well mapp inst mapp gas anyways, its a mix of propane and propylene now i think, mapp is just a name.
that unit will come in handy, i like the portability of the one i have, if it was like yours i probably wouldnt use it as much as a lot of the stuff id use it for would be outside the shed.

 

[bigegg]

the propane isnt far behind the mapp, well mapp inst mapp gas anyways, its a mix of propane and propylene now i think, mapp is just a name.
that unit will come in handy, i like the portability of the one i have, if it was like yours i probably wouldnt use it as much as a lot of the stuff id use it for would be outside the shed.

I also have a school Bunsen burner, and a smaller needle torch somewhere - they all run off propane.

I consider those little mapp bottles like the disposable Mig gas bottles - a waste of money.

I don't tend to do much hot work with the torches away from the shed - and if I did, a 15kg gas bottle with 20ft of hose is portable enough.

 

[tinman123]

id have this one with me in the cab of the digger when burning bushes so its small, horses for courses.

as for the mapp a waste of money, personally i wouldnt say that, i wouldnt use this one ever day, times id use it every 2 or 3 days and times it would sit about for a few weeks with no use but the gas in it dose last me a long time, i cant remember the last time i changed the bottle, its only small money anyways so it comes in handy.

no matter, you have heat anyways.

 

[bigegg]

as for the mapp a waste of money, personally i wouldnt say that,
<snip>
i cant remember the last time i changed the bottle, its only small money anyways so it comes in handy.

no matter, you have heat anyways.

That's almost a perfect translation of my sig


I suppose yr right - those little bottles seem to last for ages when used by a plumber.
I guess I was just judging on size

 

[tinman123]

its one of the tools id have that i couldnt fault tbh, and lord knows if i could i would.
the propane is as hot, mightnt be just as quick but its plenty, your not going welding.

 

[Shox Dr]

Ive just ordered this:

http://m.ebay.co.uk/itm/100-240V-Di...ouple-Probe-/131720388818?txnId=1241202757003

With a view to building an electric furnace/kiln/burnout oven/heat treatment oven.

The thermocouple is a k-type nominally rated to 400c (which is ok for some of the uses i have for the oven)

From reading, the k type is a particular combination of metals so *theoretically* is good for the max 1200c i need to read.

Is there an extra component (resistor?) which restricts the temperature to 400c? Or is it a result of the wires/body of the thermocouple - and would therefore need mounting inside a protective sleeve (i believe a graphite tube?)

I know a thermocouple isnt expensive so this is a mental exercise as much as anything.

Did you get round to building it?

 

[bigegg]

Did you get round to building it?

no.
i think its still in the packaging in a drawer in the spare room.
i never got round to sourcing the firebricks/castable refractory/fireclay.
its still on the list.