Position of Safety Valves

[kcameron]

I picked up a 1" Atlantic. It came with a single safety valve which is on a tee with a very small whistle. The boiler connection is a 1/8" pipe fitting, but for whatever reason, it is about 15 degrees off vertical on the boiler. This is a few inches in front of the cab. I'm the type that thinks having two safeties is important. However there is also another fitting forward, currently under a dome, also 1/8" pipe that is vertical on the boiler. I figure it is a couple of inches from the smoke box.

My question is about having safety valves in different locations on the boiler. Both the issue of off the vertical and fore and aft on the boiler. Is it reasonable, what issues might it present, etc... I plan on using safety valves from Anthony as they look really nice for 1". I also plan for adding a real whistle under the running board and the existing may stay just as a decoration.

Letting me know what others have seen or done would be good as well as theory based discussion.

[kcameron]

Might this front spot be good for one safety?

This lets you see how it is off the vertical of the boiler.

Current tee fitting for the safety/whistle combo.

I'm working on cleaning up the tender and building a new setup for the coal grate. Original design only tilted the grate and did not allow for removal or easy clean out. But the safety valves come before I get to firing it up so finding suggestions and considerations will help.

[ccvstmr]

KC...no steam dome? Okay, it is what it is. Here's an idea for consideration...remove the "T" under your whistle and safety valve and replace that with an "X" or cross fitting. Keeps all the hardware in one location. Would think with 1/8" pipe fittings and both safety valves lifted...you could still safely relieve excess boiler pressure under abnormal firing conditions. Consider this FWIW... Carl B.

[Greg_Lewis]

Ken:
Are you sure the hole is drilled and tapped at that angle and that this isn't the result of some hit or serious cross threading?

[Fender]

The problem with the forward location is that water will surge forward and aft in the boiler as you are running, so will inundate that connection at times. Usually steam for the throttle and safeties is taken from the middle of the boiler, for this reason. I’m surprised that there is Apparently no steam dome.

[kcameron]

The steam dome is under the rectangular box on the top past the whistle. The forward one is just a plug. As shown in the picture the rear hole is off center and the boss is on the boiler that way. The jacket has it with a vertical shroud so the fitting is kind of awkward.

[gwrdriver]

It never ceases to amaze me what some folks think will "get 'er done!" There's no explaining this one.

But to answer your question (if you can get past the aesthetics of it), IMHO there's no reason that safeties can't be in two locations on a boiler. However, the usual practice is to "step" safety settings by say 5psi so that one releases before the second one, but because the quantity and quality of steam might be different in remote locations the "step" setting in PSI may have to be vary from the usual guideline.

[NP317]

Another solution would be to install the two safeties on top of the steam dome!
The shroud over it would have to be altered, but the function of those safety valves would be optimum.
That's what I would do.

Another note:
On full-sized steam locomotives it is usually illegal to mount any other items on the same pipe that supports a safety valve, because that might interfere with the safety function.
Russ

[Dick_Morris]

Similar to yours, the prototype War Department S-160 Consolidations had the safety valve mounted at an angle on the boiler shell. The whistle was almost horizontal and piped from the side of the steam dome, which was under a casing, but the casing was lower than yours. They were done this way to provide bridge clearance on the European railroads. The bottom arc in the drawing is the boiler, the top arc is the cab roof.

[Fender]

Maybe the angled safety was to prevent the operator’s glasses from fogging (?)

[Bill Shields]

Or the builder had a neighbor on the next track that he did not like

[tetramachine]

If mine, make a brass block the threads onto the off set nipple. Then tap a hole vertical an as near center as you like. Add an oval shaped shroud that can hide the sin of the offset nipple, and done.