IMPROVEMENTS IN SAFETY VALVES
Year: 1854

page_text: LETTERS PATENT to William Hawthorn, of the Town and County of
Newcastle-upon-Tyne, Engineer, for the Invention of "IMPROVEMENTS IN
SAFETY VALVES."
Sealed the 6th February 1855, and dated the 8th December 1854.
PROVISIONAL SPECIFICATION left by the said William Hawthorn at
the Office of the Commissioners of Patents, with his Petition, on the
8th December 1854.
I, WILLIAM HAWTHORN, of the Town and County of Newcastle-upon-Tyne,
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN SAFETY VALVES" to be as follows:-
This Invention consists in the application of a double beat or mitre valve
as a safety valve to the boilers of locomotive, marine, land, or other steam
engines, as well as to other boilers, pipes, or vessels containing steam, water,
gases, or other liquid or aeriform bodies, under pressure or otherwise.
The double beat or mitre valve applied as a safety valve contains an annular
space or ring between the inner diameter of the external beat or mitre and
the outer diameter of the internal beat or mitre, of sufficient area to allow the
steam, &c. to have any required amount of lifting power upon the valve, or
the facility of reducing the pressure upon the valve, and consequently the

page_text: amount of dead weight upon the lever; the strength of spring or spring
balance necessary for counteracting the same to a minimum, and yet allowing
of nearly double the amount of area with the same lift, as the single mitre
safety valve now in use, for the escape of steam, water, gases, or other liquid
or aeriform bodies, under pressure or otherwise, by which the danger of
explosions from over-pressure is very considerably reduced, and the space and
strength of gearing for loading or lifting the valve proportionally economised.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Hawthorn in the Great Seal Patent Office on the
8th June 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HAWTHORN, of the Town and County of Newcastle-upon-Tyne, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of December, in the year of our Lord
One thousand eight hundred and fifty-four, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Hawthorn, Her special license that I, the said William
Hawthorn, my executors, administrators, and assigns, or such others as I, the
said William Hawthorn, my executors, administrators, or assigns, should at
any time agree with, and no others, from time to time and at all times there-
after 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 "IMPROVEMENTS IN
SAFETY VALVES," upon the condition (amongst others) that I, the said William
Hawthorn, 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 next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Hawthorn, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement,
reference being had to the accompanying Drawings, and to the letters and
figures marked thereon, that is to say :-
My said Invention consists in the application of a double-face valve, with

page_text: one or more rings on the same plane or otherwise, the faces of which may be
either flat, circular, mitre, or any other form, to be used as a safety valve to
the boilers of locomotive, marine, land, or other steam engines, as well as to
other boilers, pipes, or vessels containing steam, water, gases, or other liquid
or aeriform bodies, under pressure or otherwise. This safety valve, when
one ring is used, contains an annular space between the inner diameter of
the external face and the outer diameter of the internal face, of sufficient
area to allow the steam, water, gases, or other liquid or aeriform bodies under
pressure to have any required amount of lifting power upon the valve, or the
facility of reducing the area of the ring, and thereby the lifting power of the
valve, and consequently the amount of dead weight; the strength of spring
or spring balance applied direct to the valve, or to the end of a lever acting
on the valve, for loading it up to the required pressure, and yet allowing of
nearly double the amount of area with the same lift, as the single mitre
safety valve now in use, for the escape of steam, water, gases, or other
liquid or aeriform bodies, under pressure or otherwise; and by using a greater
number of rings with the same lift, the escapement may be increased to any
required amount, by which the danger of explosions from over pressure is
very considerably reduced, and the space and strength of gearing for loading
or lifting the valve proportionally economised. And in order that my said
Invention may be more readily understood, I shall now proceed to describe
the several Figures on the Sheet of Drawings hereunto annexed, the same
letters of reference indicating corresponding parts in all the Figures.
Figure 1 of the Drawings represents a sectional elevation of a double-face
valve a, a, loaded by a direct weight b, b, of cast iron or lead, which latter may
be incased in brass, if required; the weight is made in the form of a chimney
to convey the waste steam above the head of the engine driver; two or more
of these valves may be combined on one plane or flange. a, a, represent the
upper and lower faces, through which the steam, water, gases, or other liquid
or aeriform bodies are allowed to pass off freely, in the direction indicated by
the arrows, when the required pressure is exceeded and the valve lid raised
thereby.
a
'
Figures 2 and 2ª represent a sectional elevation and corresponding plan of
pair of double-face valves a, a, one being loaded by a lever and weight b, the
weight being suspended in a neat case, which is kept under lock and key to
prevent the engine driver increasing the load upon the valve. The second
valve is loaded by a direct acting spiral spring c applied to the valve lid, and
compressed, to give the requisite load upon the valve, by means of the lateral
vertical bolts d, d, and cross bar e (Figure 2). In this arrangement the pair

page_text: of valve seats are screwed into a flange or man-hole door, as is customary in
locomotive boilers, and by making the spindle or boss of the lid hollow; the
valve is loaded by the weight pin below the level of the faces, thus giving to
the valve a self-adjusting tendency, and not depending on the pin or boss as a
guide; they have a perfectly free action in their sockets, whereby friction is
avoided.
Figure 3 represents a sectional elevation of a single annular mitre valve
loaded by a direct-acting helical spring c, in the manner herein-before last
described; and Figure 3ª is a sectional elevation of a valve having three
concentric rings combined, which number may be increased as required, and
made with any form of face on the same plane or otherwise. These valves are
applicable to any description of steam boiler, pipe, or vessel under pressure.
Figures 4 and 4 represent a sectional elevation and plan of an annular
valve with flat faces a, a, such valve being loaded by a lever and the ordinary
spring balance f.
Figure 5 is a sectional elevation of a double-face valve with case and seat
a, a. This valve is represented as being partly loaded by a dead weight b
inside the valve case, and partly by a direct-acting spring balance.f, attached
direct to the valve spindle.
In the several Figures 1, 3, 4, and 5, the valve seats are represented as
being cast in one piece with the flange, by which they are bolted to the boilers,
pipes, or valve cases.
Figure 6 is a sectional elevation of a double-face valve a, a, applicable to
marine and other steam engine boilers. It is loaded merely by the dead
weight 6 inside the valve casing, but, if desirable, it may be loaded by a direct-
acting spring, spring balance, or lever, acted upon by a spring balance or
suspended weight, as herein-before described and illustrated by the Drawings.
Figure 7 represents a double flat-faced valve a, a, shewn partly in section
and partly in elevation. This arrangement of safety valve is applicable to
hydraulic mains, and all pipes or vessels containing steam, water, gases, or
other liquid or aeriform bodies, under pressure or otherwise. The loading of
this valve may be effected by any of the methods at present in use, or by those
herein-before described and represented in the annexed Drawings. In the
valves represented by Figures 6 and 7, the valve seats are made with pro-
jections or flanges cast upon them, and are securely held thereby between
the two flanges of the valve cases.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that I do not confine or restrict

page_text: myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without
deviating from the principles or main features of my said Invention; but what
I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent, is, the
application and use of a double-face valve with one or more rings, having the
faces on the same plane or otherwise, as a safety valve for steam generators
generally, or for pipes or vessels containing steam or water, or gases or
other liquid or aeriform bodies, under pressure or otherwise, as herein-before
described.
In witness whereof, I, the said William Hawthorn, have hereunto set
my hand and seal, the Twenty-third day of May, One thousand eight
hundred and fifty-five.
WILLIAM HAWTHORN. (L.S.)