A NEW OR IMPROVED SELF-ACTING PRESSURE INDICATING ESCAPE VALVE FOR STEAM BOILERS AND OTHER PURPOSES
Year: 1872

page_text: LETTERS PATENT to John Smith, of Old Ford, in the County of
Middlesex, Engineer, for the Invention of "A NEW OR IMPROVED
SELF-ACTING PRESSURE INDICATING ESCAPE VALVE FOR STEAM BOILERS AND
OTHER PURPOSES."
Sealed the 10th January 1873, and dated the 26th October 1872.
PROVISIONAL SPECIFICATION left by the said John Smith at the
Office of the Commissioners of Patents, with his Petition, on the
26th October 1872.
I, JOHN SMITH, of Old Ford, in the County of Middlesex, Engineer,
do hereby declare the nature of the said Invention for "A NEW OR
IMPROVED SELF-ACTING PRESSURE INDICATING ESCAPE VALVE FOR STEAM BOILERS
AND OTHER PURPOSES," to be as follows (that is to say) :-
This Invention relates to a new or improved self-acting pressure
indicating escape valve for steam boilers and other purposes, which
possesses, amongst others, the following advantages, viz., that it may be
set to act at any required pressure, and that when so set it will sound
an alarm immediately such pressure be exceeded, at the same time
freeing the boiler from the excess of pressure by providing for the escape

page_text: of steam, and likewise that when once set it cannot be tampered with,
and is so simple that it is impossible for it to get out of order.
A simple method of carrying my Invention into effect is as follows:-
Into a suitable seating secured to the top or other convenient part of the
boiler, and with a circular opening therein forming a communication
with the interior of the boiler, I drop the lower and closed end of a
hollow spindle or plug, which is ground to fit the said circular opening,
so that when held down firmly thereto, either by a weight or spring, it
will form a perfectly steam-tight joint. The lower portion of this spindle
or plug is enveloped in a casing or jacket, which receives the steam
issuing from underneath the said spindle or plug, when it is raised by
the pressure within the boiler, and from this casing the steam passes
into the interior of the said hollow spindle or plug through openings
formed in its sides in that portion of it which is enveloped by the said
casing surrounding its lower portion and is thus allowed to escape. The
said spindle or plug is held down in its required position by any suitable
weight or spring arrangement, the said weight or the power of the said
spring being regulated or fixed according to the pressure of steam at
which the valve is required to act. The whole apparatus is then
enveloped in a casing to prevent its being tampered with, the only egress
therefrom for the steam to escape being provided with a whistle, so that
an alarm will be sounded during the whole time the steam is escaping.
This valve will thus be found an effective check on the safety valve in
case of its being over weighted or not acting at the proper pressure from
any other cause, and will also enable any defect in the pressure gauges
which might prove fatal to the boiler to be detected.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Smith in the Great Seal Patent Office on
the 11th January 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN 3
SMITH, of Old Ford, in the County of Middlesex, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of October, in the

page_text: year of our Lord One thousand eight hundred and seventy-two, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Smith, Her special
license that I, the said John Smith, my executors, administrators, and
assigns, or such others as I, the said John Smith, my executors, admi-
nistrators, 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 "A NEW OR IMPROVED SELF-
ACTING PRESSURE INDICATING ESCAPE VALVE FOR STEAM BOILERS AND OTHER
PURPOSES," upon the condition (amongst others) that I, the said John
Smith, my executors or administrators, 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 John Smith, 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 thereof, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon:
This Invention relates to or consists in a new or improved self-acting
pressure indicating escape valve for steam boilers and other purposes,
which is as follows:-Into a seating formed in the top of a suitable
plug, screwed into or otherwise secured to the top or other convenient
part of the boiler, and with a vertical bore therethrough communicating
with the interior of the boiler (the top of which bore is formed into the
said seating), I drop the lower and closed end of a hollow spindle or
plug, which lower end is ground to fit the said seating, so that when
held firmly down thereon a perfectly steam-tight joint will be formed.
The lower portion of this spindle or plug is enveloped by a casing or
chamber, which receives the steam issuing from underneath the said
spindle or plug when raised by the pressure within the boiler, and from
this chamber the steam passes into the interior of the said hollow spindle
or plug through openings formed in its sides in that portion of it en-
veloped by the said chamber and ascending the same escapes out of its

page_text: upper end. The said spindle or plug is held down in the required
position by any suitable weight or spring arrangement, the weight or the
power of the spring being regulated or fixed according to the pressure
of steam at which the valve is intended to act. The whole apparatus,
or such part of it as found necessary, is then enveloped in a casing to
prevent its being tampered with, and when desired, the egress for the
steam escaping is provided with a whistle, so that an alarm will be
sounded during the whole time the steam is escaping.
In the accompanying Drawings, Figures 1 to 3 illustrate one form of
my improved valve, designed especially as a check on the safety valve,
and to indicate any dangerous pressure of steam in the boiler by sounding
an alarm; Figures 4 to 7 illustrate a second form, designed for use in
cases where the sounding of an alarm would be objectionable, but to act
at a given pressure and provide an escape for the excess of steam; and
Figures 8 to 12 illustrate a third form, designed to act both as a safety
valve and to sound an alarm immediately a dangerous pressure of steam
is reached.
Figure 1 is a vertical central section; Figure 2, a horizontal section,
taken at the line a, b, Figure 1, and Figure 3, an elevation; Figure 4 is
a vertical central section; Figure 5, a sectional plan at the line c, d,
Figure 4; Figure 6, a sectional plan at the line e, f, Figure 4; and Figure 7,
an elevation; Figure 8 is a vertical central section, but shewing part of
the internal arrangements of the valve in complete elevation; Figure 9.
is a sectional plan at the line g, h, Figure 8; Figure 10 is also a sectional
plan, but at the line i, j, Figure 8; Figure 11 is a transverse central
vertical section of the lower part of the valve; and Figure 12 is an
elevation. The same letter, wherever it occurs, indicates the same or
corresponding parts.
A is the plug, which is screwed into (or otherwise suitably fixed to)
the top or other convenient part of the boiler, and has a vertical bore B
through it communicating with the interior of the boiler. The top of
this bore is bevelled out so as to form a scating for the lower end of the
hollow spindle or plug C (which is formed into a valve) to rest thereon.
These are ground to fit one another, so that when held firmly together
a perfectly steam-tight joint will be formed. The lower portion of this
spindle or plug C is enveloped by a chamber D, which receives the steam
issuing from underneath the spindle or plug when raised by the pressure

page_text: of steam within the boiler, and from this chamber the steam passes into
the interior of the spindle or plug C through transverse openings E
formed through its sides, and ascending the same escapes out of its
upper end. The spindle or plug C is held down in the required position
by the spring F, the lower end of which acts on the ring washer G, which
rests on a shoulder or ledge formed on the spindle C and the upper end
against the ring washer H, which also forms a guide for the upper end
of the spindle or plug C, and is held down in position by the top of the
surrounding casing I, which is made to completely envelope the spring,
thus effectually preventing its being tampered with. The top of this
casing is formed by the extended base or lower portion of the whistle J
(see Figures 1 and 3), which is so arranged in position that the steam
escaping from the hollow spindle C will have to pass through the whistle,
and thus sound an alarm during the whole time the steam is escaping.
In the form of valve shewn at Figures 4 to 8, the whistle is dispensed
with, and the top of the hollow spindle or plug C is covered by a dome K,
round the bottom of which are formed a series of holes L for the escape
of the excess of steam liberated by the lifting of the hollow spindle or
plug C. In this form the washers G, H, are also dispensed with, the
upper end of the spring F acting direct against the top of the sur-
rounding casing I, and the lower end direct on to a shoulder formed on
the hollow spindle or plug.
In the form of valve shewn at Figures 8 to 12, and which is designed
to act both as a safety let-off and alarm valve, the modifications in form
from that first described are principally such as are rendered necessary
by the increased size of the valve, and in a contrivance for easing or
raising the valve by means external and apart from the pressure of the
steam within the boiler, in order that the valve may also serve as a
let-off valve. In this case the spindle C is provided with a ring shoulder M,
which is acted against on its under side by two levers N attached to a
horizontal spindle O, one end of which is supported in a blind bearing P,
the other passing through a stuffing-box Q, and having attached to its
extremity a lever R. Thus by raising the lever R, the short levers N
will be brought to act against the under surface of the shoulder M, thus
raising the hollow spindle or plug C, and allowing the steam to pass up
the same and escape in the manner already described. By this arrange-
ment for lifting the plug C no means are afforded for holding it down, so
that the valve cannot be overweighted and thus tampered with. The

page_text: For this
whistle in this case is fixed in the side of the chamber D instead of on the
top of the apparatus, as herein-before described, and is so arranged that
it will be sounded only when the spindle C is raised by an excess of
pressure of steam within the boiler, and not when it is raised by the
lever R to let off the steam, as if allowed to sound in the latter case, it
would prove of great inconvenience and be of no service.
purpose the whistle is so placed in relation to one of the short levers N,
that as the said lever N is raised by the action of the lever R, it will
cover over the inner end of the aperture leading to the whistle and thus
prevent it being sounded (see Figures 10 and 11), the end of the said
lever N being suitably formed for the purpose. An arrangement is also
provided for setting up or slackening the spring F by raising or lowering
the plate or disc S, which also forms the top of the surrounding casing I.
This is effected by supporting the said plate S between nuts T, which
are screwed on to bolts T¹, so that by raising or lowering the said nut
the plate S may be raised or lowered as required. Those of the said
nuts T which are above the plate S are enclosed by the cover U, so that
they cannot be tampered with when once set, and those of the nuts T
which are below the plate S, as also the bolts themselves and the spring
are completely enclosed by the surrounding casing I, which in this case is
made of two pieces hinged together, as at I, and fastened when in
position, and closed by a lock, as at I³. The spring F is in this case
made considerably larger than the spindle C which it surrounds, and the
object of this is that the spring may not get over heated during the
passage of the steam up the spindle C, and to further this object the
surrounding casing I, plate S, and cover U are perforated, so as to allow
of the circulation of air therethrough. V is the waste steam pipe which
in bolted on to the cover IT

page_text: It will also be obvious that my improved valve may be used for steam
pans, steam jackets, and other purposes, as well as for steam boilers.
Having thus particularly described and ascertained the nature of this
my said Invention, and the manner in which the same is to or may be
performed, I claim as my Invention to be secured by the herein-before
in part recited Letters Patent, the new or improved valve for steam
boilers and other purposes, as herein-before set forth and described, and
illustrated in the accompanying Drawings.
In witness whereof, I, the said John Smith, have hereunto set
my hand and seal, this Fourth day of January, in the year of
our Lord One thousand eight hundred and seventy-three.
JOHN SMITH.
(L.S.)
Witness,
JOHN W. GRAY, C.E.,
Offices for Patenting & Introducing Inventions,
16, Southampton Buildings,
W.C.