This is a good catch. Factory programing of our Jumo controllers were all set way too high, not accounting for the setting being in degrees C/min. I have went up to a rate of 600C/hr but only use it for quick changes in temperature of 200C or less. You can also enable temperature set point switching which will cool or heat the TC after a time you specify. This is handy to start cool down of the reactor after a sequence for a crucible change or standby.
From: Stable Isotope Geochemistry <[log in to unmask]> On Behalf Of Sarah Pederzani
Sent: Friday, January 29, 2021 4:48 AM
To: [log in to unmask]
Subject: Re: [ISOGEOCHEM] TC/EA furnace ramp temperature
I haven't tried going up to more than 300°C per hour, but if you're trying to use a steeper ramp it might be worth programming the ramp as °C/minute instead of per hour. I noticed that at least in the Jumo iTron16, the heating is actually not very even when set to 300°C per hour. Instead it heats up quite fast initially, and then much slower towards the end. I'm not sure if that is also the case with your newer model, but maybe something to look into if you're wanting to optimize the process without breaking any ceramic tubes. On a sidenote, another factor that influences whether ceramic tubes break often is how tightly the bottom reactor connection is screwed on. If you're having a lot of cracks it might be that this connection is being screwed too tightly.
On 29/01/2021 11:56, Stefania Milano wrote:
> Dear All,
> After replacing the old jumo controller with the newer model (diraTRON 116), we have been experiencing some issues with our TC/EA. By looking at the setting of the controller we realized that the ramp temperature rate was definitely too high, which was potentially the reason why we had to replace the ceramic tube so often. According to your experience which ramp rate should be used? Is it possible to go higher than 300 C per hour without damaging the ceramic? If yes, how much higher?
> Thanks in advance for any tip.
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