Old Kewanee for repair

Rodlop

Dear Gentlemen,

A friend of mine has an old Kewanee steam generator. I looks completely ruined. However he wants us to evaluate repair possibilities. Is there anywhere one can find technical specs, or drawings or at least diagramms showing the way it works?

The tube pattern doesnt looks logical to me; tubes are about 2.5" in diameter and thick walled, not longer than some 2.5 feet. Every tube passes across the hot chamber but there seems to be no connection at the end between them. Resulting in water passing only once through hot zone. I believe we are missing the end connections re-sending water several times across hot zone. Am i correct?

Tanks for any help 

Brad White

The Graveyard is full of dead heroes

A former boss of mine used to say.

Your first sentence says much to me:



"A friend of mine has an old Kewanee steam generator. I looks completely ruined"..



I admire the "make it do" mentality, but you are dealing with what should be an ASME certified pressure vessel with unknown deficiencies and operation. One could do eddy current testing, non-destructive or pressure testing to the nth degree and miss something critical.  Kewaunee is out of business as I recall. Joye Chizek sometimes lurks here or used to, she was with Kewaunee some years back.



There is not enough liability insurance nor Ambien in the world to keep me asleep at night despite all good efforts, if that boiler were in service with anything resembling a favorable opinion out of me.



Not being defeatist, just practical!



My $0.02



Brad

Joye Chizek

Can't kill Kewanees

The nice thing about Kewanees - in face most all firetube boilers - is that there is very little you can do to ruin them.Kewanee made before 1998 had 1/4" steel plates over door refractories so no replacement was ever needed. The tubes are rolled and expanded, so no welding is needed and the tubes can be easily pulled and replaced as required due to water treatment.  You'll want new combustion equipment and controls - because those have significantly improved since Kewanee quit manufacture. The basic heat exchanger is still probably solid as they were built to last 50 years and we found working units pushing 90 years old. 

Hi Brad...I'm still a consultant in the business but recently broke an ankle and am having a hard time as a hopefully repairable cripple - though doubt I was originally made as good as those old Kewanees!  Joye 

Joye Chizek

What is model number?

Do you have the model number?  I worked for Kewanee many years and have much of their newer and older technical literature. If it is a commercial/industriral boiler - not a residential - it should be able to be fixed. If it is so old that it was made to 10 sq. ft. standands, it would be oversized for any application, but is made after 1968 might need to be retubed and for sure new combustion system and controls, but heat exchanger should be solid.  National plate under jacket up by gauge glass. Watch out for misc. asbestos many people used to cover them plus around the gasketing. Sell on ebay as several people still look for these for parts.  Joye

ttekushan_3

Sounds like a box boiler

We worked on a Kewanee box boiler several years ago that sprung a tube leak. 3R5 model if I recall correctly.



If it was mine, I would have had it retubed and put a modulating burner on it, but the owners decided on replacement, since it appeared "ruined," particularly that water leg area around the bottom. It apparently leaked long enough to make things look pretty bad. Upon demolition, I saw that the fears were unfounded as the steel showed no thin spots. Thinner than new? Probably yes. But it was so overbuilt, I think the steel was still thicker than some of the cast iron sections on new boilers.



A full evaluation needs to be made by someone familiar with firetube boilers. My concern with old boilers is not so much the vessel (since the pressures are so low), but with the proper function of the safety controls, like the pressure controls and low water cutoff. Furthermore, some of those box boilers had less sophisticated burners which are usually less efficient and less safe than the large commercial burners or modern units.



For some reason or another, I felt bad about the demolition of that old Kewanee box boiler. I marveled at how well built it was as it was being cut apart. BTW, the owners have said that the fuel savings with the new boiler are not very impressive.



Terry

nicholas bonham-carter

efficiency--old versus new

probably the design of the fire-tube boiler has not changed that much since the mid 1900's. only the burner technology has really changed, and is now getting more btu's out of the therm of fuel. hence the lack of difference of fuel economy between the old kewanee and the new boiler.--nbc

The Steam Whisperer (Formerly Boilerpro)

Look at application first re Efficiency....

This is an essential factor.  I thoroughly agree that old kewanees are exceptionally well built (that's probably why they are no longer around in today's economy),  however they hold very large amounts of water...similar to most modern fire tube boilers.  When used in industrial applications with a constant heavy load and well tuned, efficiency can be exceptional....up into the mid 80's firing efficiency.  However, when used as an on/off boiler for most spaced heating applications, there are enormous wastes due to standby losses and very long warm up times before steaming.  Now adding a modulating burner that can track loads for systems that are set up for modulating input (such as orificed vapor systems or specially balanced one pipe systems or zoned systems) can have a huge improvement on this dismal efficiency.  Also using burners that have dampers that close the air intake when the fire is off also help. 



For space heating if you have a modulating burner, you could be in good shape to just rebuild the boiler.  However, if you are not going to a mod burner, the mass of the boiler is going  to work against you and you'd be better off with a couple of lower mass boilers that are stage fired.

Jean-David Beyer

Water tube boilers?

I understand that watertube boilers were used in large steam powered ships, and in power plants. They tried a few in steam locomotives and they worked, but were considered failures. It may be that a water tube boiler has to be larger so the heat loss out the sides is small compared to that used in doing useful work. I assume they excel where high steam temperatures and pressures are wanted, not in low temperature low pressure home heating systems. But, relatively speaking, I would guess they have less water in them than a fire tube boiler would have, for the same output. They might work a little better in on-off applications than afire tube boiler, but not much. As in:



It is better to have loved and lost than never to have loved at all.

But not much better.