P-Lay
Well-Known Member
Hi all. I've been thinking about making a steam kettle out of Stainless Steel. I've had this idea in my head for a while now and I'm not sure whether or not it's worth pursuing.
The idea stemmed from a picture of a steam kettle I saw while flipping through some Google images of steam kettles like this one:
The design would be a hollow, "cylinder-in-cylinder" kettle with water on the inside. I think I read a while back that Brewpastor's kettles were similar to this. When the flame is put to the bottom of the kettle, the water inside would boile and create steam to condense on the inside (and outside) walls of the kettle and transfer heat to the sides instead of only to the bottom. A pressure relief valve could be used to maintain a constant pressure/temperature on the inside chamber and blow off any additional pressure for safety purposes. I'm assuming RO/distilled water would be best so it doesn't leave deposits on the side walls.
A further idea (not pictured) would be to add a coil from the inside wall to get the steam into the middle of the kettle. This would increase the surface area and the efficiency. I don't think a coil would be a good idea for a MLT but I'm not 100% on that.
I was thinking this could be a better kettle for more efficient use of propane or natural gas in rigs who use them. An electric version (as in the picture above) could be built by just adjusting the length of the outside cylinder to accommodate more water and installing a heating element through the side wall.
Some questions I have are:
1) How much water would need to be inside so that all the water doesn't evaporate. I'm assuming this would be a bad thing. I did some test calculations and got the inside and outside volumes of the cylinders. I did not calculate for surface area though.
2) What would the temperature response be for something like this? Once you cut the heat to the bottom, there would still be some steam in the chamber that could condense on the walls. I'm assuming the rise in temperature would be conditional upon the pressure/temperature in the steam chamber.
3) What gauge stainless should be used? More for outer wall and less for inner wall for better heat exchange to product?
I was thinking it could be ordered in pieces and then tig welded together and pressure tested. You'd have 4 main body pieces (not including a coil). 1) Outside Cylinder 2) Inside Cylinder with Flanged top 3) Cone bottom for Inside Cylinder 4) Flat Bottom for Outside Cylinder. All couplers for the thermometer and dip-tubes could be welded flush with both the inside and outside walls making for a cleaner look. A false bottom would sit nicely atop the cone bottom and wouldn't need to be hinged like on some keggles (unless there's something else to get in the way of installing it).
EDIT: I was thinking that 5-15 psi would be a reasonable operating range.
(Please forgive me for the horrible drawings )
Volumes, not including material thickness or coils:
I did a little research on Toledo Metal Spinning's website and found that all pieces could be manufactured on their "standard equipment". I haven't checked the pricing for such work and probably will in the near future.
Anyway, I wanted to get some thoughts/opinions on the design. Maybe I'll end up trying it out if it's not too expensive.
The idea stemmed from a picture of a steam kettle I saw while flipping through some Google images of steam kettles like this one:
The design would be a hollow, "cylinder-in-cylinder" kettle with water on the inside. I think I read a while back that Brewpastor's kettles were similar to this. When the flame is put to the bottom of the kettle, the water inside would boile and create steam to condense on the inside (and outside) walls of the kettle and transfer heat to the sides instead of only to the bottom. A pressure relief valve could be used to maintain a constant pressure/temperature on the inside chamber and blow off any additional pressure for safety purposes. I'm assuming RO/distilled water would be best so it doesn't leave deposits on the side walls.
A further idea (not pictured) would be to add a coil from the inside wall to get the steam into the middle of the kettle. This would increase the surface area and the efficiency. I don't think a coil would be a good idea for a MLT but I'm not 100% on that.
I was thinking this could be a better kettle for more efficient use of propane or natural gas in rigs who use them. An electric version (as in the picture above) could be built by just adjusting the length of the outside cylinder to accommodate more water and installing a heating element through the side wall.
Some questions I have are:
1) How much water would need to be inside so that all the water doesn't evaporate. I'm assuming this would be a bad thing. I did some test calculations and got the inside and outside volumes of the cylinders. I did not calculate for surface area though.
2) What would the temperature response be for something like this? Once you cut the heat to the bottom, there would still be some steam in the chamber that could condense on the walls. I'm assuming the rise in temperature would be conditional upon the pressure/temperature in the steam chamber.
3) What gauge stainless should be used? More for outer wall and less for inner wall for better heat exchange to product?
I was thinking it could be ordered in pieces and then tig welded together and pressure tested. You'd have 4 main body pieces (not including a coil). 1) Outside Cylinder 2) Inside Cylinder with Flanged top 3) Cone bottom for Inside Cylinder 4) Flat Bottom for Outside Cylinder. All couplers for the thermometer and dip-tubes could be welded flush with both the inside and outside walls making for a cleaner look. A false bottom would sit nicely atop the cone bottom and wouldn't need to be hinged like on some keggles (unless there's something else to get in the way of installing it).
EDIT: I was thinking that 5-15 psi would be a reasonable operating range.
(Please forgive me for the horrible drawings )
Volumes, not including material thickness or coils:
I did a little research on Toledo Metal Spinning's website and found that all pieces could be manufactured on their "standard equipment". I haven't checked the pricing for such work and probably will in the near future.
Anyway, I wanted to get some thoughts/opinions on the design. Maybe I'll end up trying it out if it's not too expensive.