Autoclave heater elements

[Chris Whitehead]

God I love this forum.

Today I was working on an autoclave - big bugger - 415v, 3ph. Wrapped around it are four heater elements top on one phase, bottom on another phase and two middle ones on the 3rd phase. One of these has broken whilst they were changing a thermocouple. These elements have been in use at 700oC for 40 years! No wonder they broke. And we all know that the rest will soon be giving up the ghost on all the other furnaces.

I checked the ohmage on the working elements - around 20 to 40 ohm. These elements are about four meters long and coil round and round this autoclave's pressure vessel.

Two questions:

Is this value to be expected for continuity measurement?

and

Where can I purchase new, tailor made heater elements? What do I ask for? Who do I ring?

 

[Knobhead]

This may be a stupid question but have you contacted the manufacturer (if they are still going). The first port of call. After that Google bespoke heater elements.

 

[Chris Whitehead]

lol, if it is a stupid question then we have all asked the same question recently!! These autoclaves were installed in 1972. We are out of luck I'm afraid, but surely someone must do heater elements. These autoclaves are about 6 foot tall and weight about a ton. I'm kind of thinking that now I'm responsible for fault finding when there's a problem with this lot they are about to start going wrong all time. It'll be a laugh if anything.

Best forum out there

 

[Knobhead]

Some where in the horrible dark recesses of my mind, there was a company that made carbon/ceramic elements for me for a 1750°C kiln. As I recall they also did specials for most applications using conventional materials.
Based in Wales somewhere. Give me time to go through some old files.