Author Topic: Help with fittings on a Boiler  (Read 13286 times)

Offline Ye-Ole Steam Dude

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Help with fittings on a Boiler
« on: September 06, 2017, 03:01:06 PM »

Good day all,

Need some help with out fitting a new Boiler. I am working on a new design for a small boiler and I want to be sure that I install (weld) enough fittings for the accessories. Here is what I have so far;

One each ½" outlet for:
Temp Gauge
Pressure Gauge
Relief valve ***
Steam Out ***
Main Fill ( 1" size )

Two each ½" outlet for:
Sight Glass

*** I am thinking that I can “T” off one of these outlets for a Whistle.

I can use the Main Fill to empty the unit so have not drawn a “drain” outlet.

Do I need anything else?

Thanks,
Thomas

Offline steamboatmodel

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Re: Help with fittings on a Boiler
« Reply #1 on: September 06, 2017, 03:44:13 PM »
Hi Thomas,
What size and style are you doing?
Gerald.
Be wary of strong drink. It can make you shoot at tax collectors--and miss. Lazarus Long

Offline crueby

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Re: Help with fittings on a Boiler
« Reply #2 on: September 06, 2017, 03:48:53 PM »
Possibly a drain fitting at the bottom would save having to tip the unit over to drain, and you need a place for air to come in when draining anyway.
From the dimensions on the bushings, sounds like a large boiler?

Offline Ye-Ole Steam Dude

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Re: Help with fittings on a Boiler
« Reply #3 on: September 06, 2017, 04:05:31 PM »
Possibly a drain fitting at the bottom would save having to tip the unit over to drain, and you need a place for air to come in when draining anyway.
From the dimensions on the bushings, sounds like a large boiler?

Hi Chris,

Yep you are right I will add the drain. It will be 6x6x16 hopefully big enough to run most of my engines.

Thank you.

Thomas

Offline Ye-Ole Steam Dude

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Re: Help with fittings on a Boiler
« Reply #4 on: September 06, 2017, 04:12:14 PM »
Hi Thomas,
What size and style are you doing?
Gerald.

The Boiler will be 6x6x16 and will be a horizontal style. It will have an electric heating element with a control box of my own design. The Temp and Pressure will be controlled with digital power regulator and remote sensors ( I hope ? ).

Thomas

Offline crueby

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Re: Help with fittings on a Boiler
« Reply #5 on: September 06, 2017, 04:26:46 PM »
Sounds nice! Hope you do a build log of it, love to see how it goes together.

Offline Ye-Ole Steam Dude

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Re: Help with fittings on a Boiler
« Reply #6 on: September 06, 2017, 04:41:34 PM »
Sounds nice! Hope you do a build log of it, love to see how it goes together.

Hey again Chris,

I will do a build log here as soon as I get started on it. Just placed an order for the "guts" of the Control Unit with Auber Instruments. I will make a list of the items and part numbers and post them here later on.

Thomas

PS, I went ahead and added 2 extra fittings just in case....

Offline Jasonb

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Re: Help with fittings on a Boiler
« Reply #7 on: September 06, 2017, 04:47:19 PM »
Over here we have to have two means of filling the boiler, if a pump or injector should fail you can still get water into it without risk of running low or having to drop the fire.

Is that 1/2" NPT you are talking about, seems a bit big to me for a 6" dia boiler, 1/4NPT would be fine for most, 3/8 NPT for the manual fill, 1/4" for pump/injector clacks.

I'd be inclined to have a large dia flange on the top to take a steam dome, you can then connect steam outlet, safety valve and whistle to this. It will help prevent priming and reduce the chance of a fountain of hot water when the safety valve blows.
« Last Edit: September 06, 2017, 05:03:47 PM by Jasonb »

Offline Ye-Ole Steam Dude

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Re: Help with fittings on a Boiler
« Reply #8 on: September 06, 2017, 05:37:56 PM »
Over here we have to have two means of filling the boiler, if a pump or injector should fail you can still get water into it without risk of running low or having to drop the fire.

Is that 1/2" NPT you are talking about, seems a bit big to me for a 6" dia boiler, 1/4NPT would be fine for most, 3/8 NPT for the manual fill, 1/4" for pump/injector clacks.

I'd be inclined to have a large dia flange on the top to take a steam dome, you can then connect steam outlet, safety valve and whistle to this. It will help prevent priming and reduce the chance of a fountain of hot water when the safety valve blows.

Hello Jason,

I am using the 1/2" for several reasons. Most of the "accessories" that I will be fitting to the Boiler have 1/2" threads. The RTD (remote sensor) that send the signal to the Digital Control Units is also 1/2" and I do not want to adapt up to that fitting.

I will have to consider the Dome and do some more designing and drawing from my original Concept. I am attaching a .pdf of the Concept Design.

Thank you for the help.
Thomas


At this time I will manually fill the tank and not use a pump. I have not calculated the total "run" time at say 5-PSI, but there will not be any need to fill while in service.

Offline crueby

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Re: Help with fittings on a Boiler
« Reply #9 on: September 06, 2017, 06:20:30 PM »
Since you mentioned a welded shell and the drawing shows the square shape, I take it that the boiler shell will be steel of some sort, with welded seams vs silver soldered? Does being electric heated rather than a gas or coal flame help out with being steel, vs the typical round tube copper?

Very interesting, looking forward to the build!

 :popcorn:

Offline Ye-Ole Steam Dude

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Re: Help with fittings on a Boiler
« Reply #10 on: September 06, 2017, 07:03:43 PM »
Since you mentioned a welded shell and the drawing shows the square shape, I take it that the boiler shell will be steel of some sort, with welded seams vs silver soldered? Does being electric heated rather than a gas or coal flame help out with being steel, vs the typical round tube copper?

Very interesting, looking forward to the build!

 :popcorn:

Hey again,

Yes it will be made from 6 x 6 x .188wall steel (A36) square tube. Steel does not conduct heat (heat transfer) as well as copper and the Element will not work as hard heating up the water. In other words, less heat loss due to absorption by the metal. Yes again on Square shape v Round. Think of an end view with the heat source in the center below the water line on A) round and the amount of water within that say half circle. Then B) same except in a square shape, in a half square, much more water.

Almost 100% of the heat from the element will go into heating up the water, opposed to an external heat source.

Thomas

Offline Ye-Ole Steam Dude

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Re: Help with fittings on a Boiler
« Reply #11 on: September 06, 2017, 07:10:03 PM »

@Jasonb, thank you for the suggestion for a dome. Attached is my revised "concept" drawing now with a "stove pipe" ( not really ). This "dome" will be made from 1-1/2" square tube and will allow raising the Steam Out and the Relief Valve up further away from the water level.

It also appears to now have a smoke stack which I really like. This new arrangement allows me to move some of the other fittings which also helps a lot.

Thank you again for this great suggestion.

Thomas

Offline Jasonb

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Re: Help with fittings on a Boiler
« Reply #12 on: September 06, 2017, 08:14:23 PM »
What sort of pressures are you thinking of. We would never be allowed to have flat surfaces like that without additional stays to stop the thing bulging out like a football.

Offline ddmckee54

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Re: Help with fittings on a Boiler
« Reply #13 on: September 06, 2017, 08:36:29 PM »
Thomas:

Don't know if you've already covered this or not, but I've got a couple of questions.

1) What are you using for a heating element?
2) How did you determine if that heating element would be large enough to supply the volume of steam you need at the pressure you want?

I've been kicking this idea around in my head for a while, and I've found information that will hopefully allow me to convert Lbs/hour of steam into Watts.  From this I SHOULD be able to determine the heater size needed to run a specified size of engine at a given RPM.  BUT, I don't have a lot of confidence in my calculations.  What can I say, I'm a EE, not an ME - I wrangle angry pixies for a living.

Don

Offline Ye-Ole Steam Dude

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Re: Help with fittings on a Boiler
« Reply #14 on: September 06, 2017, 09:34:43 PM »
What sort of pressures are you thinking of. We would never be allowed to have flat surfaces like that without additional stays to stop the thing bulging out like a football.

Hello again Jasonb,

Relief valve will be 20 psi so I will be well within the safe limit of the chamber.

Thanks again for you good help,
Thomas