How does a steam “fired” kettle work ?
I understand there is a steam jacket but that is all I know. The steam is injected into the cavity between the kettle and the jacket and then what ?
Where does the steam/condensation exit ?
How hot is the boiler/steam ?
What happens if there is condensation in the steam jacket ? Where does the water go ?
What pressure is the steam jacket run at ?
Thanks
I don’t know all the questions to your answers but the steam is forced through the jacket under pressure. It is extremely hot - hot enough to kill you should you be unfortunate enough to be near a rupture.
There won’t be condensation because it’s so hot the water will be in gas form the entire time it is in use.
There are ways to use steam not under pressure and have it exit to the atmosphere but steam run under pressure has to be done very carefully and is required to be carefully inspected by certified inspectors. It’s serious stuff.
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Some breweries have steam Calandrias. Those can be internal or external. From a search, first hit.
You do need a condensate return to the boiler (or just a drain, but obviously that’s wasteful). At least that’s been my experience with the 15 psi steam systems I’ve brewed on. Maybe with higher-pressure systems there’s no risk of dropping below boiling, or maybe it’s just an issue because of our altitude.
I know about high pressure steam (4 bars) mostly from Europe and low pressure steam (below 15 psi) mostly in US.
I just got a quote for 15 BBL brewhouse and just a boiler without installation was quite expensive.
A brewery here in Eugene (Falling Sky) bought a beautiful German steam system. They were about 3 months late in opening becasue they couldn’t get the steam up to temp. I don’t know what the exact issue was, though.
“There won’t be condensation because it’s so hot the water will be in gas form the entire time it is in use.”
That doesn’t really make sense. The steam could be superheated so much that it doesn’t condense in the kettle, but if it did that, a) it wouldn’t be transferring much heat as most of the heat transfer occurs in the gas to liquid transition and b) if it didn’t condense, you’d have to condense it after the kettle so that you could return it back into the boiler. Its really hard (inefficient) to pressurize steam to put it back in the boiler. Its quite easy to pump condensed steam (water) back into the boiler.
Gasses can get pretty hot. I think it’s why the call them steam fired.
Admittedly I’m not a steam engineer so whatever. I did get a quote on a boiler and steam fired kettle but what shocked me was the cost of installation. So, in a couple years when we move to our new location and start working on the steam installation I’ll be better prepared to answer you question.
Until someone can completely explain it in this thread I think the best answer is: Magic.
Disclaimer - I am not a steam or boiler engineer, and it has a been a long time since those engineering thermodynamics courses.
The steam would come in at high Temp and Pressure and once the steam loses heat, some will condense, and there would be a condensate drain, and the condensate would return to the boiler reservoir.
The temperature depends on the pressure of the system, at 15 PSI (29.7 PSI absolute) the temp is about 249F, which would boil wort if there is enough supply steam. I don’t know what brewery boilers operate at, 10 PSI (24.7 PSI absolute) would probably get a boil going.
Steam systems are not to be taken lightly, inspections and other certification are needed. Bad things can happen with steam under pressure, so one needs to have safety in mind with steam applications.
A boiler heats treated water under pressure. Steam evaporates from this heated tank and travels to an exit pipe/supply line at or near the top of the tank. The pressure of tank determines the temperature of the steam. Most boilers for brewing operate under 15psi, which means that they are and fall under low-pressure boiler regulations, and steam at 12psi is roughly 250 degrees F (google for steam temp charts). A temperature controller maintains the temperature of the boiler and the boiler is equipped with PRVs, VRVs (Vacuum), water level high and low and temperature limit detectors.
The steam follows the exit pipe to the consumer(s). The consumers either have a manual or a temperature/process controller-operated valve or both to control the inlet of steam to a jacket(s) on the vessel near the upper half of the jacket if it is a vertically positioned jacket. The jack should have a PRV and VRV. When the steam comes in contact with the wall of the jacked it dumps its heat on the jacket, condenses and falls to the bottom/low point of the jacket where a condensate outlet is located.
The condensate outlet should have a steam trap (bucket steam traps are common, reliable and cheap) - which allows condensate to pass but not steam. It is possible to operate without this, but its not particularly safe (steam exiting to work-place) and its extremely wasteful (energy loss). The trap outlet either drains to the environment, again very wasteful, or goes to a re-circulation tank which collects condensate and by a float-operated pump returns the condensate to the boiler tank.
All of these pipes and jackets should be insulated to avoid being wasteful - very wasteful - and exposing hot surfaces to flesh.
I’ve left out supply line condensate handling, particulate filters/traps & check valves, proper installation of all these parts, weep lines, supply & return line sizing and blow-down and periodic maintenance and testing procedures. All of this is important for safe and efficient operation of a steam boiler & system and entire books are dedicated to the science of steam - and this is just my limited knowledge.
Nice first post.