Crown steam boiler being used for bakery proofer

frank s · August 2022

Hello all, I left the northern lands 17 yrs ago and am In sunny south florida. Got called to a commercial bakery where they have a crown steam boiler to provide steam to their bread proofer, it's a standard 200K btu steamer, system designed by an old ( navy engineer) unit is only using 1 - 2" supply pipe which is reduced to 1" within 18"s no return line. Unit has LWCO and auto feed. Is it reduced to 1" simply for velocity? the steam is controlled by a solenoid valve which is actuated by a honeywell control that measures temp/humidity. The proofer (actually a converted walk-in box) is 12' x30' and inside it has what looks like a large gas train with nozzles that expel the steam with a trough below to collect condensate which gets drained to a floor drain. Anyone see anything like this before, maybe school me a little? All knowledge greatly appreciated.

EdTheHeaterMan · August 2022

We used to deliver oil to the Philadelphia Soft Pretzel Co. that boiler did double duty. Steam heat for the conventional heating radiators and process steam to the pretzel ovens to produce the brown coating over the soft pretzel dough during the cooking process.

I had another customer in Dennisville NJ that used a Columbia commercial steam boiler to make steam that was used for the farm. No condensate return, the steam was just expelled out into a building for some farming process. There was a valve that opened to let the steam into the building. There was a smaller Tee fitting to 1" pipe with a 1" high temperature hose that has a cleaning nozzle at the end of hose with insulated handle on the valve. Probably used for cleaning machinery.

Since both of these were unusual uses for these boilers, I just did normal maintenance on the burner and some additional flushing of the lower boiler piping.

Since you are using lots of fresh water to feed this boiler, you can expect that boiler to fail about every 10 years or so. To make the boilers last longer there are water treatment devices for this type of boiler system. My boiler owners were not interested in the extra expense of the water treatment system.
They just complained about the piece of junk boilers that never last very long.

Jamie Hall · August 2022

As @EdTheHeaterMan implied, your biggest concern here is your feedwater quality. Total Dissolved Solids isn't that much of a hassle, but hardness is. Unfortunately, so are chlorides, so unless your feedwater is naturally soft there is a problem: I really can't recommend ion exchange softening, as it raises chlorides. Also, it would be best if the feedwater were close to neutral in pH.

You will want to blow the boiler down -- otherwise not suggested! -- fairly regularly using the bottom drains to get rid of solids -- more often if the TDS is at all elevated and, if the water is at all hard you may need to descale the boiler from time to time; there are treatments for this, but take the boiler off line when you use them, and flush them out and refill the boiler before you come back on line.

The reason people are fussy about pipe size and so on on heating boilers is to get the steam as dry as possible, but that is not a concern in this application, so the piping is at least adequate, if not perfectly fine.

EBEBRATT-Ed · August 2022

They also usually heat the feed (make up) water in these situations

EdTheHeaterMan · August 2022

Dan has an article about this practice where a small 30 or 40 gallon water heater would be used to preheat the feed water and then a Spirovent placed between the water heater discharge, and the boiler. This low tech solution was able to prolong the boiler life by removing micro-bubbles of dissolved gasses in the otherwise lower temperature feed water

@Erin Holohan Haskell was able to find that article in pretty short order the last time I needed it for my Dennisville Customer.

Erin Holohan Haskell · August 2022

@EdTheHeaterMan, here it is: https://heatinghelp.com/systems-help-center/steam-boilers-in-food-processing-applications/

mattmia2 · August 2022

EdTheHeaterMan said:
We used to deliver oil to the Philadelphia Soft Pretzel Co. that boiler did double duty. Steam heat for the conventional heating radiators and process steam to the pretzel ovens to produce the brown coating over the soft pretzel dough during the cooking process.

The brown comes from dipping the pretzels in lye, the base makes the flour brown more quickly. The steam lets the dough rise more before the outside sets and changes the texture of the crust. Almost all commercial bread ovens have steam injection.

The water heater before the boiler also creates and removes some of the precipitate so it isn't created in the boiler.

pedmec · August 2022

this set up is pretty common in commercial bakery. the steam coats the bread and and causes the outside to get crispy, if i remember right. but they use clean steam. dedicated steam line. cant imagine using steam coming out directly out of a cast iron boiler.

EdTheHeaterMan · August 2022

pedmec said:
this set up is pretty common in commercial bakery. the steam coats the bread and and causes the outside to get crispy, if i remember right. but they use clean steam. dedicated steam line. can't imagine using steam coming out directly out of a cast iron boiler.

There is the recommended way to do things with food grade equipment that costs 4 times the price of the cast iron Crown boiler for a large residence. Then there are the DIY bakers that look at the cost of a CROWN boiler and say". Steam is steam. How dirty can steam get, It's a gas from boiling water. And there was this guy with a bakery in East Bugfart, New South England that published an article in Bakers Monthly Magazine in 1963 (that is the Popular Mechanics for bakers) that shows you how to do the same thing with a Crown boiler. What does a health inspector know about boilers? ...and to be sure... Steam IS Steam!

But what do I know about baking bread. I just fix oil burners!