AN IMPROVED LOW-WATER ALARM FOR STEAM-BOILERS."
Year: 1881

page_text: LETTERS PATENT to Charles Henry Smith, of Whalley, in the County of
Lancaster, for an Invention of "AN IMPROVED LOW-WATER ALARM FOR
STEAM-BOILERS."
PROVISIONAL SPECIFICATION left by the said Charles Henry Smith at the
Office of the Commissioners of Patents on the 10th August 1881.
CHARLES HENRY SMITH, of Whalley, in the County of Lancaster.
IMPROVED LOW-WATER ALARM FOR STEAM BOILERS."
"AN
The object of this Invention is to construct a simple appliance for ordinary
steam boilers to give an audible alarm whenever the water in the boiler falls
below its proper level, and thus to prevent accident to the boiler or flues from
deficiency of water.
Into the front end plate of the boiler I screw from the inside a conical plug
valve, the opening through which is in the form of a narrow horizontal slot (say,
about seven eighths of an inch long by three thirty seconds of an inch high). The
screwed end of the body of the valve projects through the front of the boiler, and
onto it is screwed, outside the boiler, a steam whistle or "buzzer."
To the ends of the conical plug of the valve is attached by a fork a hollow rod
or lever, to the outer or free end of which is attached a hollow copper ball or
float.
The angle at which the hollow rod or lever is attached to the plug is so arranged
that when the water in the boiler is at its proper working level and the hollow
ball floating on the surface thereof the valve is closed, and no steam can escape
through it.
But should the water supply fail from any cause, and the level of the water in
the boiler become lowered, the ball falls with it and opens the valve, the steam
commencing to blow off when the water has fallen about an inch and a half, and
blowing off "full" when the water has fallen three inches.
There is a fixed stop placed beneath the hollow rod or lever which supports it at
this point, and keeps the steam blowing off "full" if the water level should fall
even lower.
The steam in escaping sounds the whistle or "buzzer," and thus gives the
alarm.
As the feed is pumped into the boiler the valve will be closed, and the alarm
cease sounding as soon as the water has risen to within about an inch and a half
of its proper working level.

page_text: -
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Henry Smith in the Great Seal Patent Office on the 10th
February 1882.
CHARLES HENRY SMITH, of Whalley, in the County of Lancaster.
IMPROVED LOW-WATER-ALARM FOR STEAM BOILERS."
AN
The object of this Invention is to construct a simple appliance for ordinary
steam boilers to give an audible alarm whenever the water in the boiler falls.
below its proper level, and thus to prevent accident to the boiler or flues from
deficiency of water.
Such being the nature and object of my said Invention, I will now proceed to
describe in detail the manner in which the same is to be or may be performed or
carried into practical effect; and in order that the same may be clearly understood,
I have annexed hereunto a Sheot of Drawings illustrative thereof, and have marked
the same with figures and letters of reference corresponding with those in the
following explanation thereof:-
--
Fig. 1 on the annexed Sheet of Drawings is a sectional elevation of part of a
steam boiler with my improved low water alarm applied thereto, Fig. 2 is a plan
view of the apparatus, and Figs. 3, 4, and 5 are enlarged views representing
respectively sectional and front elevations and a plan view of the conical plug
valve hereinafter described.
e, e.
Into the front end plate a, a, of the boiler I screw from the inside a conical
plug valve b, b, the opening through which is in the form of a narrow horizontal
slot c, c, (say, about 7 of an inch long by 3/3 of an inch high) see also enlarged
views, Figs. 3, 4, and 5. The screwed end d, d, of the body of the valve b, b,
projects through the front of the boiler, and onto it is screwed, outside the boiler,
a steam whistle or "buzzer " To the ends of the conical plug 61, 61, of the
valve b, b, is attached by a fork f, f, a hollow rod or lever g, g, to the outer or free
end of which is attached a hollow copper ball or float h, h. The angle at which the
hollow rod or lever g, g, is attached to the plug b¹, b¹, is so arranged that when
the water in the boiler is at its proper working level, indicated by the dotted
line A, B, Fig. 1, and the hollow ball h, h, floating on the surface thereof, the
valve b, b, is closed, and no steam can escape through it.
But should the water supply fail from any cause, and the level of the water in
the boiler become lowered, the ball h, h, falls with it and opens the valve b, b, the
steam commencing to blow off when the water has fallen about an inch and a half,
as indicated by the line C-D, and blowing off "full" when the water has fallen
three inches, indicated by the line E-F. The lever and ball are shewn by dotted
lines in their lowest position (see Fig. 1).
There is a fixed stop k, k, placed beneath the hollow rod or lever g, g, which
supports it at this point, and keeps the steam blowing off "full" if the water level
should fall even lower.
The steam in escaping sounds the whistle or "buzzer” e, e, and thus gives the
alarm.
As the feed water is pumped into the boiler the valve b, b, will be closed, and
the alarm cease sounding as soon as the water has risen to within about an inch
and a half of its proper working level, that is, to about the level indicated by the
line C-D, Fig. 1.
Having now described the nature and object of my said Invention, together with
the manner in which the same is to be or may be performed or carried into practical
effect, I wish it to be understood that I claim as my Invention,―
The improved construction of low-water alarm for steam boilers, consisting

page_text: principally of the combination of a hollow ball or float connected by a hollow lever
to a conical plug valve inside the boiler, with a whistle or "buzzer" fixed outside
the same.
In witness whereof, I, the said Charles Henry Smith, have hereunto set my
hand and seal, this Seventh day of February, in the year of our Lord One
thousand eight hundred and eighty two.
HARLES HENRY SMITH. (L.S.)