IMPROVEMENTS IN SAFETY VALVES AND ARRANGEMENTS FOR PREVENTING DAMAGE TO OR THE EXPLOSION OF STEAM BOILERS
Year: 1867

page_text: LETTERS PATENT to Thomas Wood, of the City of Manchester, in the
County of Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN
SAFETY VALVES AND ARRANGEMENTS FOR PREVENTING DAMAGE TO OR THE
EXPLOSION OF STEAM BOILERS."-A communication from abroad by Murdoch
Macpherson, of the Baltic Iron Works, St. Petersburg, Russia.
Sealed the 29th October 1867, and dated the 2nd May 1867.
PROVISIONAL SPECIFICATION left by the said Thomas Wood at the
Office of the Commissioners of Patents, with his Petition, on the 2nd
May 1867.
I, THOMAS WOOD, of the City of Manchester, in the County of Lancaster,
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN SAFETY VALVES AND ARRANGEMENTS FOR PREVENTING DAMAGE TO OR THE
EXPLOSION OF STEAM BOILERS," a communication from Murdoch Machpherson, of
the Baltic Iron Works, St. Petersburg, Russia, to be as follows:-
The Invention consists in an arrangement and combination of two valves
both opening outwards, one of the valves being weighted within the boiler by
a weight or weight and lever, the other valve being weighted by a weight and
lever, having its fulcrum jointed to a stem from the first-named valve, this
lever acting upon the second valve through a jointed link; this arrangement
makes it impossible to load the valves with more weight than is intended, as
any addition to the weight upon the lever at the exterior of the boiler will act
upon the second valve as a fulcrum to open the first valve. The lever for

page_text: weighting which is inside the boiler is connected with the feed water or other
float, so that when the water gets too low the weighted end of the lever will be
lifted, and thus the safety valve will be opened, which will give notice of low
water and will woment ceplosion or injury in case of neeluct
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Wood in the Great Seal Patent Office on the
29th October 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
Wood, of the City of Manchester, in the County of Lancaster, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of May, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirtieth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas Wood, Her special license that I, the said Thomas
Wood, my executors, administrators, and assigns, or such others as I, the
said Thomas Wood, my 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 of Man, an Invention for "IM-
PROVEMENTS IN SAFETY VALVES AND ARRANGEMENTS FOR PREVENTING DAMAGE TO
OR THE EXPLOSION OF STEAM BOILERS," a communication from Murdoch
Macpherson, of the Baltic Iron Works, St. Petersburg, Russia, upon the
condition (amongst others) that I, the said Thomas Wood, by an instrument in
writing under my hand and seal, 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 immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Thomas Wood, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement and accompanying Drawing, that is to say:
The Invention consists in an arrangement and combination of two valves
both opening outwards, one of the valves being weighted within the boiler by

page_text: a weight or weight and lever, the other valve being weighted by a weight and
lever, having its fulcrum jointed to a stem from the first-named valve, this
lever acting upon the second valve through a jointed link; this arrangement
makes it impossible to load the valves with more weight than is intended, as
any addition to the weight upon the lever at the exterior of the boiler will act
upon the second valve as a fulcrum to open the first valve; the lever for
weighting which is inside the boiler is connected with the feed water or other
float, so that when the water gets too low the weighted end of the lever will
be lifted, and thus the safety valve will be opened, which will give notice of
low water, and will prevent explosion or injury in case of neglect.
The Figure upon the accompanying Sheet of Drawing will explain more
fully the Invention communicated to me, it is a sectional elevation of part of
a steam boiler with the improved apparatus applied.
A, part of the shell of the steam boiler; b, the fire flues; C, the water level of
the boiler; d, the feed pipe; e, the float attached to the rod (e¹) for actuating
the feed valve and indicating the level of the water; e, a guide for the float
rod (e); A¹ is the steam dome; f, the safety valve casing having two branches,
from one of which the steam is taken for use, and from the other is taken the
steam passing through the safety valves. It will be seen that there are two
valves (g and h) in the casing (f), and that both valves have stems which
pass through a cover or plate secured to the top of the casing (f). To the
under side of the valve h one end of a rod (h¹) is jointed, the other end being
jointed to a lever (h³), having its fulcrum (h) upon a bracket secured to the
inside of the shell of the boiler; this lever (h³) is weighted by a weight (h').
To the end of the stem of the valve h projecting through the plate a lever (g')
is jointed, and to this lever a link or centre piece (92) is jointed, which rests
upon the end of the stem of the valve g, as shown. This lever (g¹) has a
weight (g) upon it which keeps down the valve g. The weight (h) is
sufficiently heavy to put the required weight on the valve h, and also to resist
and balance the action of the weight g³, so that any weight added to the
lever g¹ over and above that intended will reduce the pressure acting to keep
down the valve h. The lever h³ is made to extend to the float rod (e¹), so
that a collar (e) upon the rod (e¹) will come against the end of the lever
when the water is too low, and will act to lift the valve h, thus allowing the
steam to escape and give notice of low water and relieve the boiler at the same
time.
I have now particularly described the nature of the Invention communicated
to me and the mode of carrying it into effect, and claim as the Invention
secured to me, the combination and arrangement of two safety valves, sub-

page_text: stantially as herein-before described; and also the combination of a float with
the arrangement of safety valves, as herein-before described and illustrated by
the accompanying Drawing.
In witness whereof, I, the said Thomas Wood, have hereunto set my
band and seal, this Twenty-fifth day of October, in the year of our
Lord One thousand eight hundred and sixty-seven.
THOMAS WOOD. (LE.)