steam retort control 1

[amazing azza]

Hello friends, I have a steam retort where the temperature sensing element is so short that it does not extend out of its bung. (Shell has a weld-on threaded bushing and thermometer screws into there). Now, I have a sneaking suspicion that this will measure the temperature of the shell more so than the temperature of the product. Agree?

So, I am thinking of replacing it with a pressure sensor to be used as input to the temperature controller. I think it will give a more accurate sense of what is going on inside the retort. Or is it not worth it and I should just get a longer thermometer?

 

[thebard3]

I like a pressure sensor for control on a steam vessel because there is no lag or thermal loss like you describe, but be aware that the atmosphere is not really saturated steam until the majority of the original air atmosphere is displaced. You should expect higher pressure than you would normally see in a saturated steam environment until then.

Brad

It's all okay as long as it's okay.

 

[amazing azza]

but be aware that the atmosphere is not really saturated steam until the majority of the original air atmosphere is displaced

Ah, indeed. This may make the Come Up step (vent open, flushing with steam until set temp is reached) less accurate, but then again how exact does it really need to be? After the flush is complete, vent is closed, the real temperature control begins, and now we are fully saturated steam and the reading should be accurate. Agree?

 

[thebard3]

I agree.

Brad

It's all okay as long as it's okay.

 

[amazing azza]