Author Topic: Help with fittings on a Boiler  (Read 14009 times)

Offline paul gough

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Re: Help with fittings on a Boiler
« Reply #75 on: November 12, 2017, 09:09:06 PM »
Hi Thomas, Thanks for the PM and link, been a bit wobbly lately so have a lot of catching up to do. Regards Paul Gough.

Offline Ye-Ole Steam Dude

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Re: Help with fittings on a Boiler
« Reply #76 on: November 12, 2017, 10:51:07 PM »
Hi Thomas, Thanks for the PM and link, been a bit wobbly lately so have a lot of catching up to do. Regards Paul Gough.

Hello Paul,

You are more than welcome. Sorry to hear that you haven't been up to speed lately.

Have a great day,
Thomas

Offline kvom

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Re: Help with fittings on a Boiler
« Reply #77 on: November 13, 2017, 03:02:35 PM »
My only comment on this build is that doing pressure testing with air vs. water isn't allowed at my club.  The hydro test requires that the boiler be full.  Failure is much less dramatic in this scenario.

Offline Ye-Ole Steam Dude

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Re: Help with fittings on a Boiler
« Reply #78 on: November 13, 2017, 07:00:34 PM »
My only comment on this build is that doing pressure testing with air vs. water isn't allowed at my club.  The hydro test requires that the boiler be full.  Failure is much less dramatic in this scenario.

Hi kvom,

Yes I understand and do agree with you 100%. However the underwater test was only at 50psi and was just to confirm that all the silver solder joints had no leaks. I later plugged all of the openings but the one air-in with the globe valve. Then filled it full of water and submerged it again and applied 90psi and held it for 30-minutes. I closed the valve and disconnected it from my air line to confirm that the valve was also holding OK.

The ASTM code shows the actual burst pressure on 2-1/2" Type "L" pipe is over 3000 pounds, so my main concern was not with the pipe or fittings but with the silver soldered joints. I wanted to be sure the Steam Trap was completely "finished" before attaching it to the Boiler.

Thank you and I appreciate your comment, this is what makes a Forum great.

Have a great day,
Thomas

Offline steamboatmodel

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Re: Help with fittings on a Boiler
« Reply #79 on: November 14, 2017, 06:07:42 PM »
Since the steam trap is at boiler pressure, instead of draining it to atmosphere would it not be better to connect it back to the boiler?
Gerald.
Be wary of strong drink. It can make you shoot at tax collectors--and miss. Lazarus Long

Offline Ye-Ole Steam Dude

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Re: Help with fittings on a Boiler
« Reply #80 on: November 14, 2017, 09:09:11 PM »
Since the steam trap is at boiler pressure, instead of draining it to atmosphere would it not be better to connect it back to the boiler?
Gerald.

Hello steamboatmodel,

I have never seen that done before, but maybe with a check valve in the discharge line it could be done. With equal pressure from the bottom of the Steam Trap and the return line mounted above the water level, I'm not sure if you could "push" the liquid (water) back up that high. Gerald, I just don't know, maybe someone will tell us if it can be done and how.

Thank you and have a great day,
Thomas

Offline MJM460

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Re: Help with fittings on a Boiler
« Reply #81 on: November 15, 2017, 03:31:27 AM »
Hi Thomas, there is no reason not to run the liquid outlet back to the boiler, if it was a full size boiler, the whole device would be inside the steam drum with the outlet just running to the bottom of the drum.  But it would take some ingenuity to fit one into a model.  No need for a check valve, in fact better without it.  The only critical thing for running it back to the boiler is that the highest liquid level and the highest hole in the centre tube in your separator must be above the liquid level in the full boiler.

If I understand your design, the steam from the boiler goes in the top, flows down and out through the holes in the centre tube and completes a 180 degree change of direction to flow back up to the outlet in the side near the top of the outside shell.  That 180 degree change of direction is critical to the good separation of the liquid phase.  If you have some good insulation, there should be no significant condensation, it is mostly carryover from the boiler, and may be continuous until the boiler level gets down a bit.  Or your steam turret may minimise it if I remember your boiler design correctly.   You don't seem to have much volume in the separator to accumulate water below the top holes in the centre tube, so better to drain it back to the boiler continuously.

The return to the boiler, (near the bottom, not above the liquid level), acts like a u-tube.  If some water builds up on one side, it will flow around the bottom until the levels are equal, or out at the top of the other side into the boiler if it reaches that first. I am sure you know the principal.  The pressure at the liquid surface on both sides is the same, so the flow is driven purely by the differences in level.  If you put a check valve you will need a few extra inches of height to provide the pressure to lift the ball.  You can work it out from the weight of the ball divided by the area of the hole you drill for the seat.  I think I would run the u-tube down as much as you have space for, then back up to the bottom of the boiler to the boiler inlet to make a clear "U", not just a single 90 degree elbow.

I know you called it a steam trap and I have called it a separator.  Yo'all often use different terms to the rest of the English speaking world, it is just terminology, I can deal with that.  In fact though, I should change that, I have found that in the Deep South, you use the same words, you just say them differently.  It is further North that they actually use different terms, making conversation more confusing.  And anyhow, you are all way, way North to us!  So a little mystery to be discussed another time.

Looking forward to seeing the operation of your separator.

MJM460

The more I learn, the more I find that I still have to learn!

Offline Ye-Ole Steam Dude

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