IMPROVEMENTSIN SAFET Y VALVES
Year: 1875

page_text: LETTERS PATENT to William Lockwood, of Sheffield, in the County
of York, Engineer, for the Invention of "IMPROVEMENTSIN SAFET Y
VALVES."
Sealed the 27th July 1875, and dateḍ the 22nd May 1875.
PROVISIONAL SPECIFICATION left by the said William Lockwood at
the Office of the Commissioners of Patents, with his Petition, on
the 22nd May 1875.
I, WILLIAM LOCKWOOD, of Sheffield, in the County of York, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN SAFETY VALVES," to be as follows:-
The object of this Invention is to attain effectively the well known
objects for which this description of apparatus is used, and the principal.
novelty of the improvements constituting the Invention consists :-.
1. In combining within any suitable chest or casing a valve, herein-
after referred to under the letter ("a"), for the escape of steam at over-
i

page_text: arranged within the boiler.
And, 2. In combining within any suitable chest or casing the valves
(a) and (b) with a third valve, herein-after referred to under the
letter (""), for the escape of steam at over-pressure, weighted by a
dead weight.
In both modifications the working parts are contained within an upper
cylindrical or other casing, which is bolted to an under cylindrical or
conical casing bolted to a flanged seating set upon the shell of the boiler.
Rising from the lower casing are bolted thereto three or more arms
carrying a cylinder (with a closed top) enveloping a cylindrical top affixed
to the valve (a), and part way down which is a cross diaphragm or plate
with a central nut, in which is screwed a stoke, passing through the top
of the enveloping cylinder, and having near its top an inverted dish-
shaped washer, bearing equally at all parts upwards against a socket
arranged in the top of the enveloping cylinder; and between this washer
and the diaphragm the flat conical spring is arranged, and it thus
exerts its pressure downwards upon the valve (a), which (underneath its
diaphragm) is provided with one, two, or more concentric exterior faces
bearing against an equal number of seatings arranged within the under
casing; these facings and, seatings are for the escape of steam from the
boiler on over-pressure. This valve (a) is further provided with two or
more concentric interior seatings, against which in the first modification
bear an equal number of faces on the valve (6), a stoke screwed into
which depends into the boiler and is there pivotted to the lever above
mentioned; near this pivotted part the lever is slotted transversely, so
as to have a limited play about a pivot pin or fulcrum passing through
the slots and carried by a rod depending from the interior of any fixed
part of the casing below all the valves. The lever at one end is further
provided with a float, and at the other end with a weight. The effect of
this combination and arrangement is that on a sufficiency of water the
valve (6) is caused by the high position of the float to bear hard upon
its seatings in the valve (a), and that as the water lowers, this force
is generally lessened, till at low-water mark the low position of the float
causes the valve (6) to be fully opened and lifted from its seating in the

page_text: valve (a), and necessarily causes it to remain so till the water is admitted
to the boiler and again raises the float; thus the steam is allowed
instant and complete escape, and it then passes away through circum-
ferental openings above the seatings for the faces, of the valve (a).
The pressure of the flat conical spring can be adjusted only by the
insertion of washors above the diaphragm, so that neither of the valves
can possibly be tampered with. To the top of the stoke emerging from
the top of the enveloping cylinder is fastened a chain secured to one end
of an easing lever carried upon the top of the upper casing, and by
which the pressure upon the boiler can be tested at any time.
In the second modification the essential difference is that the valve (c)
is interposed between the valves (a) and (b); thus the seating of the
valve (6) is upon the valve (c), and the seating of the latter upon the
valve (a), and the seating of the last in or upon the under casing, as
above. The valve (c) is weighted with a depending cylinder or tube
(a dead weight) enveloping the stoke of the valve (6), and acts with the
valve (a) to relieve any over-pressure of steam. Of course upon a
sudden over-production of steam from any event all the valves overcome
their respective loads and lift instantly. Thus upon the application of
these improvements explosions are prevented from all causes, excepting
that of a bad or thoroughly worn boiler, the consequences arising from
deficiency of water, negligence, inattention, ignorance, or wilful malice,
being perfectly provided against.

page_text: cessors, give and grant unto me, the said William Lockwood, Her special
licence that I, the said William Lockwood, my executors, admini-
strators, and assigns, or such others as I, the said William Lockwood,
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 "IMPROVEMENTS IN SAFETY VALVES," upon the condition (amongst
others) that I, the said William Lockwood, my executors or admini- 1
strators, by an instrument in writing under my, 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 I, the said William Lockwood, 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 in writing, and on reference being had to
the accompanying Sheet of Drawings, that is to say :-
The object of this Invention is to attain effectively the well known
objects for which this description of apparatus is used, and the principal
novelties of the improvements constituting the Invention consist,-
1. In combining within any suitable description or kind of chest or
casing a valve (herein-after referred to under the letter a) for the escape
of steam at over-pressure, weighted by a flat conical spring having direct
action with a valve (herein-after referred to under the letter b) for the
escape of steam at low water, weighted by a balanced (float and weight)
lever arranged within the boiler.
And, 2. In combining within any suitable description or kind of chest
or casing the valves a and b with a third valve (hereinafter referred to
under the letter c) for the escape of steam at over-pressure, weighted by
ȧ dead weight.
Such being the nature and objects of my said Invention I will now

page_text: or may be performed or carried into practical effect; and in order that
the same may be distinctly understood I have annexed hereunto one
Sheet of Drawings illustrative thereof, and have marked the same with
figures and letters of reference corresponding with those in the following
explanation thereof, that is to say :—
In both of the above-mentioned modifications the working parts are
mostly contained within an upper casing, which is bolted to an under
cylindrical or conical casing, or a single casing 1 bolted to a flanged
seating 3 set upon the shell of the boiler 4. Rising from the interior
of the casing, as dotted, or depending, as in full lines, and bolted thereto
are three or more arms 5 carrying a cylinder 6 (with a closed top)
enveloping a cylindrical top 7 affixed to the valve a, and part way down.
which is a cross diaphragm or plate 8 with a central nut 9, in which is
screwed a stoke 10 passing through the top of the cylinder 6, and
having near its top an inverted dish-shaped washer 11 bearing equally
at all parts upwards against a socket 12 arranged in the top of the
cylinder 6, and between this washer 11 and the diaphragm 8 the flat
conical spring 13 is arranged, and it thus exerts its pressure downwards
upon the valve a, which (underneath its diaphragm 8) is provided with
one, two, or more concentric exterior faces 14 (ono only being shown
on the accompanying Drawings) bearing against an equal number of
seatings 15 arranged within the casing 1; these faces 14 and seatings
15 are for the escape of steam from the boiler 4 on over-pressure. The
valve a is further provided with one, two, or more concentric interior
seatings 16, against which (in the first modification, which is illus-
trated in Figure 1) bear an equal number of faces 17 on the valve 6,
a stoke 18 screwed into which depends into the boiler 4, and is there
pivotted to the lever 19 (above mentioned); near this pivotted part at 20
the said lever is slotted transversely, so as to have a limited play about
a pivot pin or fulcrum 21 passing through the slots and carried by a
rod 22 depending from the interior of any part of the casing 1 below
all the valves. The lever 19 at one end is further provided with a
float 23, and at the other end with a weight 24. The effects of this
combination and arrangement are that during a sufficiency of water the
valve 6 is caused by the high position of the float 23 to bear hard upon
its seating 16 in the valve a, and that as the water lowers this force is
gradually lessened, till at low water mark the low position of the float 23
causes the valve 6 to be fully opened and lifted from its said seating,.

page_text: and necessarily causes it to remain so till the water is admitted to the
boiler and again raises the float 23, thus the steam is allowed instant
and complete escape, and it then passes away through circumferential
openings 25 made in that part of the cylindrical top 7 beneath its
diaphragm 8, and also through the apertures 2 in the casing 1, and
continuous working under such dangerous conditions is rendered
impossible.
The pressure of the spring 13 can be adjusted only by the insertion
of washers above the diaphragm 8, so that neither of the valves can
possibly be tampered with. To the top of the stoko 10 is fastened
a chain 26 secured to one end of an easing lever 27 carried by the
casing 1 which is provided with a cap 29), and by which lever 27 the
pressure within the boiler can be tested at any time.
In the second modification, which is illustrated in Figure 2, the
essential difference is that the valve c is interposed between the valves
a and b, thus the seating of the valve 6 is upon the valve c, and the
seating of the latter upon the valve a, and the seating of the last in or
upon the casing 1, as above. The valve c is weighted with a depending
cylinder or tube 30 (a dead weight) enveloping the stoke 18 of the
valve b, and acts with the valve a to relieve any over-pressure of steam.
Of course upon a sudden over-production of steam from any event all the
valves overcome their respective loads and lift instantly. Thus upon
the application of these improvements explosions are prevented from
all causes, excepting that of a bad or thoroughly worn boiler, the con-
sequences arising from deficiency of water, negligence, inattention,
ignorance, or wilful malice, being perfectly provided against.
Having now particularly described and ascertained the nature and
objects 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
would remark in conclusion that I claim as my Invention the com-
binations within any suitable description or kind of chest or casing (1)
of the valve a for the escape of steam at over-pressure, weighted by a
flat conical spring having direct action with the valve 6 for the escape
of steam at low water, weighted by a balanced float and weight lever
arranged within the boiler; and (2) of the valves a and 6 with the
valve c for the escape of steam at over-pressure weighted by a dead
weight, together with the peculiar methods of operation and working

page_text: of such combinations, all substantially as herein-above described, and
as illustrated on the accompanying Drawings.
In witness whereof, I, the said William Lockwood, have hereunto
set my hand and seal, this Seventeenth day of November, in the
year of our Lord One thousand eight hundred and seventy-
five.