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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.
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.
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.
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
Ok, Thomas, we are talking the same language, just a minor difference in usage. Though only two m's in Aluminium. The story here goes that some executive in an American aluminium company spelt it wrong in the early days, and no one had the courage to correct him. Or perhaps no one else noticed. The extra "i" is consistent with other element naming in the periodic table but you folk are unlikely to change. It would be a huge job for not much benefit. So it just remains another linguistic difference.I am quite familiar with the automatic traps, which as you say discharge to a lower pressure return system or a drain. I have usually just put a cap in the end of a vertical pipe, with the outlet to the turbine on the side a little above. Then an automatic trap on the bottom. But in a full size plant we are dealing with much more condensate, as you know. The automatic steam trap is quite important, as I have spent much more time in commissioning than in normal operation, so more than the normal number of stop - start operations, which also means more condensate in the headers. Once the machine is running 24/7 for most of the time, it would not surprise me if they are removed the first time they give trouble, as with a continuous flow of steam they are hardly necessary, and the manual valve for the occasional startup is adequate. For your separator, the only thing I would suggest is that steam outlet stays horizontal to the engine outlet, or runs up to the engine, so that any condensate formed in that section while the engine is stationary runs back to the trap instead of into the engine. No point in going to the effort of making the trap and then draining the condensate into the engine anyway. More important in the model world than larger scale, as relatively, our engines spend more time stationary.Looking forward to seeing the complete setup is action with an engine on the trolley.MJM460
I really like that setup with the cart!