Boiler Build For American LaFrance Engine

[Jasonb]

This should give an idea though they are not teh type c

http://seddonandblack.co.uk/boiler-tube-expanders/cat_301.html

I'm sure an e-mail to Wicksteed will get you a price and US dealer.

BTW did you see the amount of tubes in that video on Wicksteeds site :

J

 

[Dan Rowe]

Jason,
Thanks for that link. That type-e expander has a very small head and will work better close to the edge of the tube sheet.

Dan

 

[steamin]

Dan, I also thank you for the link to a US dealer for the tube roller. I will give them a call Monday AM. I just had a good feeling that I came to the right spot with my questions. You guys are awesome.

JasonB, I got so excited about the tube rollers that I forgot to mention thank you for the link to the Fowler engine construction. The boiler is one beautiful piece of workmanship.

Thanks again for all your help !

 

[steamin]

I called the folks at USA Industries today. They are on central time. I quiz them about the Series 900 tube roller they had listed in their online catalog. That one is no longer available. They suggested the "AN" tube roller that is for 3/8" OD by 21 gauge. the cost was around $211.00. At this point, I may try something on my own.

 

[xo18thfa]

Dumb question here: Do you weld the end plates with the flues in and expand after or weld in the plates and run the flues thru the holes to the other end?

 

[Dan Rowe]

Larry,

They recomended 3/8 21 gauge flues but what questions did they ask?

My question is this, what is the distance between the tube sheets and what fuel are you planning for this vertical boiler?

Dan

 

[steamin]

Thanks for the photos on the tube roller. It is similar to what I had in mind. I was thinking of trying to use tapered pins for the rollers and then machine a tapered rod to work in the middle of the cage as shown in the pictures. But a s I type this reply I am thinking the angle on the tapered pins may be to great. They are 1.2 degrees per side. ????

The folks at USA asked what size of tube I was going to use. They did not recommend any particular size or gauge. I selected the 3/8" diameter per a chart they had. It listed 3/8" OD as the largest diameter to use with a 1/4" thick tube sheet. I selected the 0032" thick wall instead of the other choice 0.062" wall.

To answer the other questions, the fire will be fired with wood and the flue tubes will be 4-1/2" from the grates.

Thanks for the help

 

[steamin]

I forgot to add the distance between the the tube sheets is 5 and 1/8".

 

[Dan Rowe]

Larry,
The only thing I have seen on the relationship between the length of the tube and the inner diameter of the tube is Martin Evans formula. I found it on the web with some other basic design information here:
http://www.model-engineer.co.uk/forums/postings.asp?th=34610

If we work the problem from the direction of the tube you selected the tube length for the middle of the range of 50 to 70 times the tube ID squared is 0.3112 X 65 which gives 6.29" as the tube length.

Tube data chart: http://www.usaindustries.com/tube_gauge_chart.htm

If we work the problem from the tube length of 5.125 then we divide that by 65 and take the square root to get 0.28" for the tube ID.

Now smaller tubes are more efficeint for heat transfer but they will plug up quicker, so does anyone have any data on a vertical wood fired boiler with say 5/16" ID tubes?

Dan

 

[steamin]

Dan, great information ! I have heard of the L/D ratio. The details I never pursued. I have marveled at some model boiler makers that brag that they have just as many tubes in their boiler as the prototype and then can not understand why the boiler will not draw a draft. I will have to do some tube sheet layouts with the 5/16" OD and the 3/8" OD tubes. I am not so concerned with the amount of tubes, but would like a nice balance of firing time and boiler water capacity.

Firing time, I am not to concerned about because I am retired :big: Just some of my silly humor.

I do appreciate your input and what you have shared will make me a better model maker. Thanks

 

[Dan Rowe]

Larry,
I have been thinking about boilers for quite some time now and collecting information and tools. I checked my 3 tube rollers and they are all commercial ones with straight rollers caged at a slight angle so they are skew on the tapered mandrill and are parallel to each other.

Dan

 

[steamin]

Dan, I went to ebay and bought one of the flue tube expanders that you flagged out for me. It is the 3/8" x 17 ga.. It arrived today. The OD of the mandrel is 0.252". The rollers actually sit a little bit below this od. McMaster-Carr has some alloy 122 copper tubing in straight lengths. The size I am looking at is 3/8" od x 0.062" wall. This will give me a 0.245" id on the tubing. Now, my thought is this; dismantle the tube expander and turn the mandrel down about 0.008" to 0.010", just so it slides very nicely into the tubing. Reassemble and then roll away. Like I mention earlier, the rolls sit below the surface of the mandrel now and I think I can steal 0.004"-0.005" per side to make this tube expander work ! I thought I might go ahead and purchase a 6' length so I can turn the mandrel to the exact dimension I need. What do you think ?

 

[Dan Rowe]

Larry, the only issue I can see is the rollers might fall out of the cage if the OD is reduced but the head on that roller is adjustable and it can slip over the end of the rollers to help keep them restrained.

I was thinking a 5/16" OD 20 gauge tube which should work with no modification to the roller. I can find them in short lengths in the UK and OZ but I can not find any hard drawn 5/16" copper tube in the US. May be another reader has a good source.

Dan

 

[steamin]

HI Dan, I understand what you are saying ! I spent the last hour or so looking for 5/16" od copper tubing. Check out this link.

http://www.redmetals.com/tube_pipe/roundcoppertubing.htm

It is a company in Waterbury, CT. They list 5/16" od x 0.016" to 0.065" wall thickness. I will give a call Wednesday, 23rd to see what they have available.

In my search I found another source for small shape pieces in brass, copper and steel that will be of use in model making. That link is:

http://www.lewisbrass.com/

 

[steamin]

I just pulled my Coles Power Models Catalog #26 out and they list a 5/16" od by 22 ga. copper tube. That is a 0.028" wall thickness and would give us a 0.256" id. PERFECT I will call them Wednesday 23rd to see if they have any.

 

[steamin]

I just touched base with Coles Power Models about 5/16" OD x 22 ga. copper tubing. They do have some in stock and will be glad to cut my flue tubes to length. So I placed my request with them. Thank you Dan for all your input. As I get back to the actual boiler build, I will post some pictures of the progress. Because the boiler is an intergal part of the chassis, it will be awhile before I get back to the boiler build. I have a few more things I want to do to the chassis before I do a major disassemble to continue work on the boiler.

The other possible source I mentioned in the previous posting has 5/16" OD tubing available, but only with 0.017" and 0.032" wall thickness.

 

[sunworksco]

What is the operating working pressure of your boiler?
I'm building a vertical 7.5" diameter x 4.5" height boiler and need similar sized fire tubes.

 

[steamin]

Hi Giovanni, I plan to operate the boiler around 60 psig or less. I am not going to see how high and how far I can squirt water. Just want to have some fun and blow the whistle.

 

[sunworksco]

I'm going to have 100psi.
Do you think these tubes would have a thick enough wall thickness?
The thin walls of the fire tubes will exchange heat more efficiently.

 

[steamin]

Giovanni, I am not sure. Maybe some others can jump in here to answer that question. I did silver soldered a copper boiler yet to be pressurized. The flue tubes specs for that build was 5/16" OD x 0.032" wall. It is suppose to be able to carry 100 psig. I figure a wall thickness of 0.028" should be able to carry the 60-80 pounds I would like to have for the LaFrance.

On a different note, how do one edit their post within this forum ? I have looked high and low, what am I missing ? Thanks !