Steve, this is great.Steve Goodbody wrote: ↑Tue Nov 19, 2019 1:57 pm Hi Glenn - have forwarded the spreadsheet by Email.
Hope things work out and let us know how you get on.
Best regards
Steve
Thank you!
Glenn
Steve, this is great.Steve Goodbody wrote: ↑Tue Nov 19, 2019 1:57 pm Hi Glenn - have forwarded the spreadsheet by Email.
Hope things work out and let us know how you get on.
Best regards
Steve
All sound stuff here Glenn. If the blast nozzle is only going to be ~3/8" in diameter, I think you'll find a single hole will work just as well as a multihole design. I've seen several multiple hole nozzles tried and they didnt perform any better than a single hole, my guess being the web between the holes is too small on the miniatures for any meaningful amount of gas to be entrained. Centering the nozzle should help although being exactly in the center isnt too critical, just needs to be close. My guess would be Ottoway used a pretty decent design at the time as far as stack height, so Id say start with just the blast nozzle opening and then can fiddle with adjusting it up and down from there, though I imagine closing down the nozzle will make an improvement. It did on my shay, 1/32in too big made the locomotive a little lazy to fire and gave trouble keeping steam.Glenn Brooks wrote: ↑Tue Nov 19, 2019 2:02 pm Hello All, thanks for your comments on this.
In answer to your questions, here are a couple of data points:
- my working pressure is 143 PSI.
- existing oriface size is .238” for each nozzle, .476” total; (1/7th Cylinder dia rule should be .358” )
- nozzles are offset to the rear and left of stack center - by a significant amount
Re: fire tubes. I think my cellphone camera has foreshortened the front end boiler view a bit. The boiler has 4 rows of fire tubes, around 22 flues 1” diameter for all. They could have put 2 more on each side, I think. But overall it seems to be a standard code boiler design...
Definitely the blast nozzles are misaligned with the center of stack. - both are offset to the rear and left side of the stack.
I plan to correct the nozzle placement this winter. I would like to machine a single blast plenum connecting to the two exhaust ports, then put a four hole “pepper box “ design nozzle in the plenum. I tried to nudge the existing nozzles back into alignment, but no movement. The blast tubes are likely 65 year old black iron pipe, so Iam hesitant to try a bend the pipe as an interim measure. (Committed to one last steam up in December]
Also, in the photo, the elbows are part of the throttle plumbing. Behind them, two straight blast pipes come out of the saddle and head up into the stack. Iam thinking about replacing these old iron throttle fittings with stainless or copper pipe, curved around the outside of the firebox to each steam chest inlet. This would free up access to the flues for cleaning. Any recommendations on type of tubing to use? And does it matter the run to the left side is longer than the run to the right steam chest??
Thanks much for your recommendations!
Glenn
I found the opposite to be true. I started with a single orifice blower made from a piece of 1/4in copper tube in the shay. It was loud and used a lot of steam compared to what it generated. I switched to a blower ring with 3 1/16in or 3/32in holes drilled equally spaced and found it to be much more efficient and quieter. More smaller jets spaced far enough apart will entrain more gases before they combine in the petticoat.Glenn Brooks wrote: ↑Tue Nov 19, 2019 10:05 pm Hmmm, One more question has come up regarding round blower nozzles with multiple holes drilled in the ring.
What advantage do they offer over the traditional one nozzle blower?
Also, with multiple blower oriface, does this type use more steam than single nozzles? Hence perhaps be less efficient in terms, of steam generation?
Thanks
Glenn