Building Steam Boiler

[bc.gold 3,403]

Was originally going to make steam to distill essential oils using the old Lister generator but have decided to build a wood fired boiler instead. As this project makes progress will post pictures and such into this thread.

 

Below my first purchase, a sight glass to observe the water level inside the boiler.

 

The two valves, should the sight glass accidentally be broken these valves can be closed to preserve water and internal pressure inside the boiler allowing continued operation until the glass has been replaced.

 

On the boiler shell two more taps are installed, one is place at the absolute low water lever with the other placed where the upper top water level should be, should the sight glass become broken then the taps are used manually to observe.

 

The boiler is never filled completely to the top with water, the upper half is for steam generation.

 

Made in the USA, a pair of threaded rods are missing from the sight glass. The stays keep the valves from expanding under pressure thus keeping the sight glass intact.

 

Edited August 30, 2019 by bcgold

[ebinmaine 67,275]

[squonk 41,024]

I was about 10 feet from one of those sight glasses when it exploded on a 60 psi HP boiler. It gets your blood movin! 

[oliver2-44 9,685]

Be sure to put a safety check valve on that homemade boiler. 

 

@squonkI can attest to what your saying.  During the construction startup of 2 -600 MW generators I was up on the turbine deck when the plant lost internal power.  I was prepared for the safeties high up on the boiler to blow, had heard them many times.  But I wasn't expecting the low pressure rupture disc on top both turbines to blow. Steam turbines overate under a vacuum and with the loss of all plant power the vacuum pumps died. The building filled with steam as we ran into the nearby staircase, then it rained hot water inside the building.  After that they redesigned the plans dual electrical feed that had a flaw with a common connecting buss, which  of course where a bushing had failed. 

[Burnerman 758]

The rods that run down alongside the gauge glass aren’t holding anything. They just protect the glass from being struck and broken by accident. 

Be careful with your project. You’re the first person I’ve seen build a boiler and start with a gauge glass. 😁

[squonk 41,024]

After an annual inspection the guys put the same 100HP 60 psi boiler back together. After a couple of days one of the inspection hole gaskets blew filling the room with hot rain. fire dept shows up and they suit up and go in. I have no idea why as the e-stop was already hit and we were just waiting for the pressure to finally subside. There is a window in the boiler room door and all you could see was steam. Then a flash and those fireman ran out of that room like ants out of an anthill. a speed drive go wet from the steam and exploded! 

[Burnerman 758]

I work around 50 yr old 90#+ 4” steam lines.  We’ve got a few rooftop air handlers with steam stations inside. I just hope if one lets loose it take me out quick. Some of the new schedule 80 nipples from China have been eaten up in months. 

[bc.gold 3,403]

12 hours ago, Burnerman said:

The rods that run down alongside the gauge glass aren’t holding anything. They just protect the glass from being struck and broken by accident. 

Be careful with your project. You’re the first person I’ve seen build a boiler and start with a gauge glass. 😁

 

Collecting hardware first, it's going to be a small boiler producing saturated steam at a low pressure.

 

Some of the backyard boiler makers are using copper tubes rolled in, I prefer the steel tubes what is your opinion on welding the ends to the bottom and upper boiler plates.

 

My boiler will be operating less than 10 psi, just needs to make lots of steam to drive out the essential oils the still is only 30 gallons with an operating pressure of 130 psi, but in the future may go a bit larger.

 

To put my mind at ease when the boiler has been completed will do a hydro test.

Edited August 31, 2019 by bcgold

[Burnerman 758]

5 hours ago, bcgold said:

Some of the backyard boiler makers are using copper tubes rolled in, I prefer the steel tubes what is your opinion on welding the ends to the bottom and upper boiler plates.

I have never built a steam boiler nor retubed one so I really can’t answer construction questions. I only know a bit about steam system piping and the respect you need for steam 🙂 I strongly recommend you consult with someone who retubes boilers and understands steam boiler construction. 

Is this 10psi of steam going to be condensed and the condensate returned to the boiler? If not you can have problems from adding constant make up water. 

 Since you’re going wood fired it’ll be tricky to keep it fired to provide enough steam without exceeding 10psi. Have you thought about how you’re going to regulate the heat from your fire? 

definitely test your boiler well above your safety relief valve(s) rating.

I would also suggest a low water cutoff. Since it can cutoff the heat with a wood fire you could have it activate an audible alarm and possibly a solenoid valve to add makeup water to keep it from dry firing. 

Good luck and be careful with your build

 Greg 

[bc.gold 3,403]

With the boiler exhaust port unrestricted I'll be hard pressed to reach any pressure. Just need a steady supply of wet steam for a few hours.

 

My boiler will be a scaled down version of the one shown below.

 

 

[Burnerman 758]

If it’s unrestricted it’s not a pressure boiler then. It’s a pot of boiling water. Carry on. 😁

[bc.gold 3,403]

I had totally forgot that I have this tank and it has a very heavy wall - perfect for the boiler shell.