IMPROVEMENTS IN SAFETY VALVES FOR STEAM BOILERS
Year: 1872

page_text: LETTERS PATENT to William Lockwood, of Sheffield, in the County of
York, Engineer, for the Invention of "IMPROVEMENTS IN SAFETY
VALVES FOR STEAM BOILERS."
Sealed the 6th August 1872, and dated the 22nd May 1872.
PROVISIONAL SPECIFICATION left by the said William Lockwood at
the Office of the Commissioners of Patents, with his Petition, on
the 22nd May 1872.
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 for Steam BoilERS," to be as follows:―
This Invention relates to improvements in safety valves for steam
boilers (such valves having the dead weight principle applied thereto) and
consists essentially in weighting the valve with a fluid weight, that is,
with water supplied from and returning to the boiler by the action of
the boiler in conjunction with the means and in the manner herein-after
described.

page_text: The valve itself is secured in a cast-iron frame of such a shape as to
receive it, and in addition, to conveniently carry an annular vessel of
copper or other suitable material to receive and contain the water weight,
the valve is provided with upper openings to allow the steam to escape,
and with two or more (say three) faces, which rest upon an equal
number of seatings suitably placed and secured in or to a cast-iron
column fixed to a seating on the boiler. By this means the area of the
valve proper is reduced, while a much greater quantity of steam is
allowed to escape than in the ordinary valve.
Passing through, but connected to the valve, are three pipes of copper
or other material (two for steam and the other for water). One end of
the water pipe (for filling, weighting, and emptying the vessel) ter-
minates near the bottom of the same, whilst its other end terminates just
or at any convenient distance below the water line in the boiler. One
end of one of the steam pipes (for balancing the pressure to set at liberty
the water in the weighting vessel in case of low water in the boiler)
terminates just inside the top of the vessel, whilst its other end terminates
as above, but does not go so low in the boiler, as and for the purpose
hereafter described. (The positions of the ends of these pipes in the
boiler are in every case determined according to the lowest point at
which the boiler can be worked with safety). Whilst one end of the
other steam pipe terminates just inside the top of the vessel, and its
other end just through the inside of the valve; this pipe is provided
with a small tap, for the purpose herein-after described.
The action of the valve is similar to that of other dead weight safety
valves, the mode of weighting being as follows:-
_ As soon as the
pressure of steam is got up in the boiler the water is forced therefrom
through the water pipe into the weighting vessel, the air or steam in the
latter being provided with a suitable exit, such as an air valve placed on
the top thereof, so as not to offer by its compression any impediment to
the filling of the vessel, by which the required weight upon the valve is
attained.
In case of over pressure of steam in the boiler the valve is raised
thereby, and the steam blows off in the usual way. In case of low
water, directly the end of the steam pipe in the boiler is clear of the
water therein, the steam rushes up it and into the upper part of the
weighting vessel, and causes an equilibrium of pressure.
The water pipe

page_text: then acts as a syphon, and partially or entirely empties the weighting
vessel of the water, and so lightens the same in proportion as it is
emptied, and consequently the weight on the valve being diminished the
valve is raised by the pressure of the steam, which then gradually blows
off and so prevents accidents. The boiler is then replenished with water,
and as soon as the water rises in the boiler so as to cover the end of the
steam pipe, as above described, the action of the steam fills the weighting
vessel with water from the boiler, and the valve is again in working
order.
In case of the steam being required to be blown off at any time the
cock of the second steam pipe is opened and the steam admitted into the
upper part of the vessel, and as in the case of low water, the water is
forced thereby from the vessel back into the boiler.
on the 22nd November 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
LOCKWOOD, of Sheffield, in the County of York, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of May, in the year of
our Lord One thousand eight hundred and seventy-two, in the thirty-fifth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said William Lockwood, Her special licence that I, the
said William Lockwood, my executors, administrators, 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 FOR STEAM
BOILERS," upon the condition (amongst others) that I, the said William
Lockwood, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly

page_text: describe and ascertain the nature of my 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 accom- .
panying Drawings, that is to say :-
This Invention relates to improvements in dead weight safety valves
for steam boilers, and consists essentially in weighting the valve with a
fluid, by preference with water supplied from and returning to the
boiler.
On the accompanying Drawings Figure 1 represents a vertical section,
and Figure 2 a plan of the improved safety valve.
The valve a is secured by radial ribs 6 in a frame c, which also carries
an annular vessel d which receives and contains the fluid weight. It is
provided with upper openings, or by preference with a continuous open-
ing between the crown and circumferential part thereof, as illustrated, so
as to allow of the speedy escape of the steam. The crown part a¹ of the
valve works in some degree independently of the circumferential part a,
as at high pressure it works therewith, but at low water in the boiler it
is kept upon its seat by means of a spiral spring e, whilst the part a
lifts, and is held up thereby. The play of the spring can be adjusted by
the hand nut f. The valve is also provided with two or more (say three)
faces a³, a³, a', which rest upon an equal number of seatings g, g¹, g³,
suitably secured to a column h fixed to a seating on the boiler. The
area of the valve proper is thus reduced, while a greater quantity of
steam is allowed to escape than in an ordinary valve of similar size; for
instance, the common five inch one only gives fifteen inches circum-
ference, while the one illustrated gives thirty-five inches for the escape
of steam.
Passing through, but connected to the crown, are three pipes, two for
steam and the other for water. One end of the water pipe i (for filling,
weighting, and emptying the vessel d) terminates near the bottom of
the same, whilst its other end terminates just, or at any desired distance,

page_text: below the water line in the boiler.
One end of the steam pipe j (for
balancing the pressure to set at liberty the water in the weighting
vessel in case of low water in the boiler) terminates just inside the top
of the vessel, whilst its other end terminates as above, but does not go so
low in the boiler as the pipe i. The positions of the ends of these pipes
in the boiler are in every case determined according to the lowest point
at which the boiler can be worked with safety. Whilst one end of the
steam pipe k terminates just through the inside of the crown, and its
other end just inside the top of the vessel, but I prefer that it should
communicate from the crown with the pipe j. The pipe k is provided
with a small tap 7 between the crown and its junction with the pipe j.
The centre line of this tap is represented in Figure 1 by the red line 1-2.
The action of the valve is similar to that of other dead weight safety
valves, the mode of weighting being as follows:-As soon as the pressure
of steam is got up in the boiler water is forced therefrom through the
pipe i into the vessel d, the air or steam therein having exit through the
pipe j and tap 1, which is formed as a three-way cock, so as not to offer
any impediment to the filling of the vessel, by which the required weight
upon the valve is attained.
In case of over pressure of steam in the boiler the valve is raised
thereby and the steam blows off in the usual way; it is prevented from
being raised too high by the projecting rim m. In case of low water,
directly the end of the pipe j in the boiler is clear of the water therein
the steam rushes up it and into the upper part of the vessel d, and causes
an equilibrium of pressure; the pipe i then acts as a syphon, and par-
tially or entirely empties the vessel d of the water, and so lightens the
same in proportion as it is emptied, and consequently the weight on the
valve being diminished it is raised by the pressure of the steam, which
then gradually blows off and so prevents accidents. The boiler is then
replenished with water in the usual way, and as soon as the water rises
in the boiler so as to cover the end of the pipe j, as above described, the
action of the steam again fills the vessel d with water from the boiler,
and the valve is again in working order.
In case of the steam being required to be blown off at any time the
cock is opened, and the steam admitted into the upper part of the
vessel, and as in the case of low water, the water is forced thereby from
the vessel back into the boiler, and the weight being diminished the

page_text: steam readily blows off, the circumferential part a only of the valve
being lifted from its seating by means of the spring.
Having now described the nature and object of my said Invention for
"Improvements in Safety Valves for Steam Boilers," 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 Inven-
tion, the general construction, arrangement, and combination of the
component parts of the improved safety valve and the weighting thereof
with a fluid weight, substantially as above described, and as illustrated
on the accompanying Drawings, or any mere variation or modification
thereof acting in the same or a similar manner.
In witness whereof, I, the said William Lockwood, have hereunto
set my hand and seal, this Nineteenth day of November, in the
year of our Lord One thousand eight hundred and seventy-two.
WILLIAM LOCKWOOD. (L.S.)