IMPROVEMENTS IN SAFETY APPARATUS FOR STEAM BOILERS
Year: 1870

page_text: LETTERS PATENT to Alexander Morton Strathern, of Coatbridge,
and David Graeme Morrison, of Glasgow, both places being in
the County of Lanark, North Britain, Engineers, for the Invention
of "IMPROVEMENTS IN SAFETY APPARATUS FOR STEAM BOILERS.
PROVISIONAL SPECIFICATION left by the said Alexander Morton
Strathern and David Graeme Morrison at the Office of the Com-
missioners of Patents, with their Petition, on the 18th April 1870.
We, ALEXANDER MORTON STRATHERN, of Coatbridge, and DAVID
GRAEME MORRISON, of Glasgow, both places being in the County of
Lanark, North Britain, Engineers, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN SAFETY APPARATUS FOR STEAM
BOILERS," to be as follows, that is to say :-
This Invention has for its object the fitting of steam boilers with
simple and effective safety apparatus arranged so as to prevent over-
loading of the safety valve to indicate the level of the water, and to
cause the fires to be extinguished should the water become dangerously
low. Two safety valves are fitted in a box casting in communication
with the boiler, and one of them is loaded by means of a lever passing
out through a slot in the side of the box for the application of a weight
externally. The other valve is loaded by a lever and weight arranged

page_text: entirely within the box so that it may be locked up. The fulcrum of
the accessible or external lever is arranged to be on the other valve or
its lever, so that any attempt to overweight the accessible lever tends to
lift the inaccessible lever and valve, and so let off the steam, a com-
munication being at the same time opened with a whistle and an alarm
sounded. For indicating the water level there is a float connected to a
lever inside the boiler and a rod passes up from this into the valve box
above, being there jointed to a lever or wiper on a transverse horizontal
spindle passing out through the side and fitted with an external index or
pointer. The lever or wiper on the index spindle is placed so as to act
on one or other of the valve levers when the water level is either too
high or too low, and it then causes the whistle to sound. In addition
there is arranged within the boiler a valve and tube, the latter leading
to the fires, whilst the valve is connected to a lever placed so as to be
acted upon by the float or its lever, whenever the water level becomes
dangerously low.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Morton Strathern and David Graeme
Morrison in the Great Seal Patent Office on the 17th October 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ALEXANDER
MORTON STRATHERN, of Coatbridge, and DAVID GRAEME MORRISON,
of Glasgow, both places being in the County of Lanark, North Britain,
Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of April, in the year of
our Lord One thousand eight hundred and seventy, in the thirty-third
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto us, the said Alexander Morton Strathern and David Graeme
Morrison, Her special licence that we, the said Alexander Morton
Strathern and David Graeme Morrison, our executors, administrators,
and assigns, or such others as we, the said Alexander Morton Strathern
and David Graeme Morrison, our executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle

page_text: of Man, an Invention for "IMPROVEMENTS IN SAFETY APPARATUS FOR STEAM
BOILERS," upon the condition (amongst others) that we, the said Alex-
ander Morton Strathern and David Graeme Morrison, our executors or
administrators, by an instrument in writing under our, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent,
NOW KNOW YE, that we, the said Alexander Morton Strathern
and David Graeme Morrison, do hereby declare the nature of our said
Invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the fallowing statement
in writing, reference being had to the accompanying Drawings, that is
to say :-
Our said Invention has for its object the fitting of steam boilers with
simple and effective safety apparatus arranged so as to prevent over-
loading of the safety valve to indicate the level of the water, and to
cause the fires to be extinguished should the water become dangerously
low.
And in order that our said Invention and the manner of performing
the same may be properly understood, we have hereunto appended a
Sheet with an explanatory Drawing to be herein-after referred to,
and representing the application of our improved apparatus to a steam
boiler.
The Drawing is a vertical section as taken through the apparatus and
longitudinally through the boiler 1. The principal parts of our improved
safety apparatus are contained in a cast-iron box 2 communicating with
the boiler 1 by a short branch pipe 3, and comprise two safety
valves 4, 5, fitted to valve openings 6, 7. Onc, 4, of the valves is loaded
by means of a lever 8 passing out through a slot in the side of the box 2
for the application of a weight 9 externally. The other valve, 5, is loaded
by a lever 10 and weight 11, arranged entirely within the box 2, so that
it may be locked up. The fulcrum 12 of the accessible lever 8 is
arranged to he on the other valve 5 (or it might be on its lever 10), so
that any attempt to overweight the accessible lever S, would simply lift
the inaccessible lever 10 and its valve 5 and so let off the steam. At
the same time a whistle 13 would sound an alarm, as the valve 5 is

page_text: connected to a valve 14, which opening with it would admit steam to
the whistle. For indicating the water level there is a float 15 connected
to a counterweighted lever 16 inside the boiler 1, and a rod 17 passes up
from this into the valve box 2 above, being there jointed to a lever or
wiper 18 on a transverse horizontal spindle passing out through the side
and fitted with an external index or pointer indicated. by dotted lines
at 19. The lever or wiper 18 on the index spindle is placed so as to act
on one or other of the valve levers 8, 10 when the water level is either
too high or too low, and it then causes the whistle 13 to sound. In
addition there is arranged within the boiler 1 a valve 20 and tube 21,
the latter leading to the fire or fires 22, whilst the valve 20 has a slotted
or hooked rod embracing the float-lever 16,-so-as-to-be opened whenever
the water level becomes dangerously low, and allow the steam to escape
down the tube 21 and extinguish the fire. This provision has the
advantage over what is known as the fusible safety plug, that after it has
acted the boiler does not require to be cooled down in order to readjust
the parts, but may be at once filled up with water, the valve 20 closing
as the water rises.
Having thus particularly described our said Invention, and the
manner in which the same is to be performed, we have to state that
we do not restrict ourselves to the precise details herein described or
delineated, but that what we believe to be novel and original, and claim as
the Invention secured to us by the herein-before in part recited Letters
Patent is, the combining of the parts of safety apparatus for steam
boilers in the improved manner, substantially as herein-before described..
In witness whereof, I, the said Alexander Morton Strathern,
on behalf of myself and the said David Graeme Morrison, have
hereunto set my hand and seal, this Fourteenth day of October,
in the year of our Lord One thousand cight hundred and
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
+
A. MORTON STRATHERN. (L.S.),