|Paul Lousick||19/09/2020 14:20:12|
|1546 forum posts|
Depends on how much the holes were damaged. Small nicks or grooves can be smoothed by reaming or grinding the hole slightly larger. Roll type tube expanders easily enlarge the ends of the tubes. On one of the boilers that we overhauled with 1 1/2" tubes, some of the tube plate holes were 2 - 3mm oversize and they sealed satisfactory for a 180 psi ticket. Larger grooves have to be welded and re machined.
Cannot remember if test was 1.5x or twice WP. A tube failure is not catastropic and the boiler will not blow up, just leak.
Edited By Paul Lousick on 19/09/2020 14:22:09
|duncan webster||19/09/2020 14:49:40|
2799 forum posts
I very much doubt a model has these, but some boilers have stay tubes which are welded both ends. These are definitely structural
|noel shelley||19/09/2020 19:46:29|
|116 forum posts|
Firstly many thanks to all who have offered advice or comment. This work is being done due to a leaking tube and will be followed by an internal boiler inspection, followed by re tubing and what ever else the inspector wants. The tubes are 25 years old and one of my fears is that they will just fold up and how to get them out if this happens. The hand hole is not large !!! Even if I cut the ends off I still have to get all the bits out. I want to avoid any damage to the tube plate holes. One thought is an expanding reamer on the smoke box end to thin it, collapse whats left and then use the hydraulics to pull the fire box end and tube out having ground it back to the tube plate first ?
best wishes to all, Noel
|Chris Gunn||19/09/2020 21:47:13|
|337 forum posts|
Noel, an expanding reamer will not take much out, much quicker to make the boring bar I mentioned, and bore 1/2" back. you can do it in one cut if your tubes are 1/8" thick, leaving a 10 to 15 thou wall for example. I did some research before trying the method I describe in my article, it seemed half pulled the tubes out from the front, and half knocked them through into the firebox. Some folks I know worked on a 4" Foster, and knocked the tubes from the front into the firebox, and cut a piece off, and repeated until the tube is fully out. it is a 2 man job, 1 to hold the drift, and one to wield the sledge hammer. This seemed rather brutal to me, very hard work, and was quite time consuming, 2 or 3 tubes an evening if all went well. unless one makes a series of drift/mandrels it is not possible to support the tube internally as it is driven through. The chance of damaging the front tube plate seemed higher to me that way too.
I could get my tubes out on my own. If you plan take the tubes on your engine out this way, i am having difficulty in seeing how you could use the hydraulic rams in the firebox, or would you push from the front?
|Paul Kemp||19/09/2020 22:07:05|
|562 forum posts|
Was explained earlier in the thread. Put a threaded bar though the tube with a suitable stepped mandrel in firebox end of tube. Get a length of pipe longer than the tube over the stud in the smokebox that the OD of the tube will pass through. This puts the force onto the front tube plate right beside the tube. Thread a hollow Jack over bar against pipe, fit nut and pump. The ram expanding is the same as tightening a nut. Pulls the tube out from the front.
|vic francis||27/09/2020 22:25:59|
|53 forum posts|
Hi Noel you say that the engine is 25 years old, would that be-the original boiler? If so is there sufficient life in the boiler to merit tube removal? ? When was the last test/cert issued?
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