Stanley fusible plug

I can't find my drawing of the Stanley fusible plug.

I may have to redraw it.

It was based on a description by a Stanley owner who made his own. I seem to recall that it is a solid pipe plug drilled through with a 1/4 inch drill bit, then taper reamed with a taper pin reamer from the steam side, then filled with lead something like 1/2 inch thick. He said that his was located such that when it blew, the steam would extinguish the pilot and main burner. But it was not aimed at the jets or mixing tubes.

My memory of the details is foggy. Any information on this would be greatly appreciated.

Peter



Edited 2 time(s). Last edit at 02/07/2019 04:05AM by Peter Brow.

Judging by information in my files, it seems that the drilled plug design was a non-standard aftermarket design, and that the standard Stanley fusible plug was just a small pipe nipple filled with lead. The 1906 Stanley Instruction Manual gives the melting point of lead as 618 degrees Fahrenheit; Machinery's Handbook says 621F. A 1/8" nominal pipe nipple would be 0.269" ID for Schedule 40, and 0.215" for Schedule 80.

Firetubes must be superheating the steam a bit by the time the water level gets to 3 inches above bottom tube sheet. That is the point at which the lead in the fusible plug melts out and releases a whoosh of steam, alerting driver to shut off the burner, and thus preventing boiler damage.

One idea I had was to aim the steam exiting a blown fusible plug at a paddle on the end of a ball valve lever, so that the ball valve shuts off the burner fuel instantly and automatically if the water gets low and the fusible plug blows. Then just unscrew the blown pipe/fusible-plug, screw in a new one, and push the paddle-lever back to the valve-open position.

Interesting that the temperature of the steam output from a Stanley boiler seems to vary with the water level... at least below a certain level...

467F being the temperature of saturated steam at 500psi, but the lead fusible plug doesn't melt until 621F, which apparently is the temperature of steam from the firetube section when water level there drops to 3". Normal water level in a 14" tall Stanley boiler being about 7" above the bottom...

I have just made some computer changes, and am testing posting, editing, and other things...

Peter



Edited 1 time(s). Last edit at 02/08/2019 04:30AM by Peter Brow.

I have them Peter.
I just need to find them. There in one of my files on a memory stick. I have photos of the original.
Two nipples come up from the bottom tube plate, one higher than the other. When the water gets below the short nipple about three inches from the bottom plate the connecting pipe between the two riser’s blows out and the pipe heats up and a tee fitting with the nipple with the plug melt out, this nipple sticks out the side of the burner and blows steam out from the boiler giving you time to shut of the burner saving the bottom tube sheet. You change out the nipple with the plug and refill the boiler and go on your way.
Rolly

In January, 1985 when I purchased our first Stanley, I installed a Baker burner and I also used the fusible plug in my bottom tube sheet that it had came with. I had many melt downs of the fusible plug with the boiler still being just a little less than half full of boiler water. Apparently the Baker burner was lifting its water enough off of the bottom tube sheet to melt the fusible plug's lead. The fusible plug was a nuisance. I have since done away with the fusible plugs and in time of need, I rely of the low water safety to shut my fuel off. There was a good reason why the fusible plug was discontinued in the Stanley steam cars.

Peter I found the photos of the piping and fusible plug.
Pat from my information the fusible plug system was only used on the boilers of 250 PSI of the early and before 1906.
These are hammer in fittings and had original nipples higher up into the water about three inches.
Rolly

Rolly, My 1913 Stanley operator's instruction manual tells all about the fusible plug on page 11. The 1913 Stanley had an operating pressure of about 450 pounds, and many operate the boilers at over 500 pounds. It is possible that the fusible plug was discontinued with the introduction of the condensing car in 1915. Interesting that the instructions also say that "The fusible plug should be replaced when the boiler is cold, say once in two or three weeks." Yes, that is about how often as my fusible plug would blow out. Say, once in two or three weeks.....
SSsssteamer

Thanks Rolly and Pat! Fascinating detailed information, and great photos. Before reading your replies, I did not fully understand how the Stanley fusible plugs were plumbed, or precisely how they worked, or why they were later replaced with the expansion-tube Low Water Automatic. Now I do. Stanley cars had no lack of ingenuity.

Changing fusible plugs every 2-3 weeks, hmm. Well, I guess that answers the question; "do I want fusible plugs on my boiler?". That would be "no".

Time to dust off my "Plan B", from many years ago: an expansion-tube "Low Water Automatic". I like the setup on the Brooks steam cars; the Brooks Low Water Shutoff was nearly identical to their Stanley-like Feed Water Automatic, except that the expansion tube operated a fuel shutoff valve instead of a feed-water bypass valve. A tube connected one end of the Feed Water Automatic's expansion tube to the top of the boiler, then the other end of the Feed Water Automatic expansion tube connected to one end of the Low Water Automatic's expansion tube, which, unlike the vertical Stanley Low Water Automatic expansion tube, was nearly horizontal [steeper angle than the FWA "X-tube", though] and located several inches below the Feed Water Automatic. The other end of the Low Water Automatic's expansion tube then connected to the bottom of the boiler. This simplified the plumbing. Jeff Theobald told me that his Brooks ran great, except that the [original] boiler was too small for good performance, especially on hills.

Peter



Edited 2 time(s). Last edit at 02/08/2019 08:32PM by Peter Brow.

Stanley Terminology: Water automatic. AKA Boiler Feed Water Regulator. Maintains the boiler's water level through the thermal expansion of it's water by-pass thermal expansion tube. Low water safety AKA Low Water Automatic Fuel Shut-Off Valve. Shuts the main fuel supply off when the boiler water level gets too low. Fuel shut off is done by the thermal expansion of its thermal expansion tube.

Hi Pat,

I have long followed the terminology in the 1918 Stanley booklet "A Complete Description Of The Stanley Steam Car".

Page 22: "The Stanley Car is fitted with three automatic regulators... the feed-water automatic bypass, the low-water automatic shut-off, and the steam automatic..."

I simplify those to "Feed Water Automatic, Low Water Automatic, and Steam Automatic". Maybe your terminology is better. I have been surprised and dismayed now and then to find steam car fans who don't know what one or more of those essential controllers do, or who are not even aware that they exist and have operated very successfully on the road for over a century now.

Peter



Edited 1 time(s). Last edit at 02/09/2019 08:37AM by Peter Brow.

Peter Brow Wrote:
-------------------------------------------------------
> Hi Pat,
>
> I have long followed the terminology in the 1918
> Stanley booklet "A Complete Description Of The
> Stanley Steam Car".
>
> Page 22: "The Stanley Car is fitted with three
> automatic regulators... the feed-water automatic
> bypass, the low-water automatic shut-off, and the
> steam automatic..."
>
> I simplify those to "Feed Water Automatic, Low
> Water Automatic, and Steam Automatic". Maybe your
> terminology is better. I have been surprised and
> dismayed now and then to find steam car fans who
> don't know what one or more of those essential
> controllers do, or who are not even aware that
> they exist and have operated very successfully on
> the road for over a century now.
>
> Peter

Peter, Well done. As long as we all speak the same language by using the same words, then we will all have a better understanding of the others' ideas trying to be conveyed. So often I see the Stanley automatics' names misused, and that it scares me in that possibly someone could misunderstand the message's intent and they may do damage to equipment or to their selves.

Thanks Pat. For "explaining power", it's hard to beat the names of the 3 automatics given in the Stanley Model 740 booklet "Pointed Questions And Direct Answers Covering The Stanley Steam Car".

In the propulsion system diagram in that booklet, the Steam Automatic is called the "Steam Pressure Regulator", the Feed Water Automatic is called the "Boiler Water Level Regulator", and the Low Water Automatic is called the "Low Water Fuel Shutoff". The name of each component describes its function.

I am considering changing to using the terminology in the Model 740 booklets & diagrams. However, the Model 735 "Automatic" terms have become an ingrained habit, dating back to my first few years of steam car study, when I only had the Model 735 diagram/literature for reference.

I suspect that the Stanley Brothers preferred the "Automatic" names, to emphasize that in their later cars the basic powerplant system controls operated automatically -- while running, no manual input is needed to control water feed to boiler, or fuel flow to the burner, or to shut off the burner if boiler water level gets dangerously low.

On his page at stanleymotorcarriage.com, Robert E. Wilhelm states that the success of the expansion-tube Low Water Automatic that led the Stanley Brothers to adopt the expansion-tube Feed Water Automatic.

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