Uniformly heated drum, NOT! 1

[itsmoked]

I'm working on a large machine that has an oil heated drum that runs partially submerged in tar.

This is essentially what it looks like and how it's currently built.

Dimensions are not exact and are in feet. (About 8 feet long)

As depicted they pump 250F° oil into the center pipe.
The pipe has a few hole pairs drilled 180° apart on the center in-feed pipe.
The oil leaves the drum out the end as shown.


Looking at this I think it really can't work very well because of the lack of pressure control on the oil, poor flow rate control, and probably lousy flow sharing by all the holes.

They've dissembled the drum looking for clogs or gunk and there has not been any.

They are complaining that the surface temperature of the tar soaked surface is all over the place varying by more than 70F° in various poorly defined regions. This is causing the laminating process to be.... sub par..

Is there a more modern standard way to be doing this that provides a modicum of uniformity? Maybe a single eductor at the end of the in-feed pipe? Or ?





Keith Cress
kcress -

http://www.flaminsystems.com

 

[MintJulep]

This machine has got a bunch of push buttons and VFD speed knobs and valves and levers and cranks.

Process nightmare. Lots of things for operators to twiddle, and every operator "knows" what works best.

Cheap and easy from controls aspect:

Increase the oil flow. Decrease the oil temperature.

This should:
Lower the temperature of the hot spots.
Improve mixing inside the roller.
Increase the convection coeficient at the inner surface of the roller.
Decrease the axial temperature gradient.

 

[itsmoked]

Lots of things for operators to twiddle, and every operator "knows" what works best.

So true.. Oddly every operator can get the machine to produce 'their way' which is the 'right way'.


The original oil heating system burnt this place down, (note the ashes sitting on the horizontal surfaces), and the reason I'm tasked with this machine's control. They have a new oil heating system about to be installed. I guess I'll have to wait to see how that affects the roll's temp gradient issue (using a thermal imager) before trying to modify the roller.


3DDave; I hadn't thought of the buoyancy aspect. Excellent point.

Keith Cress
kcress -

http://www.flaminsystems.com