IMPROVEMENTS IN SAFETY AND OTHER OUTLET VALVES FOR STEAM BOILERS
Year: 1872

page_text: LETTERS PATENT to George Weir, of Glasgow, in the County of
Lanark, North Britain, Engineer, and James Weir, of Liverpool,
in the County of Lancaster, Engineer, for the Invention of "In-
PROVISIONAL SPECIFICATION left by the said George Weir and
James Weir at the Office of the Commissioners of Patents, with
their Petition, on the 12th June 1872.
We, GEORGE WEIR, of Glasgow, in the County of Lanark, North
Britain, Engineer, and JAMES WEIR, of Liverpool, in the County of
Lancaster, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SAFETY AND OTHER OUTLET VALVES FOR STEAM BOILERS,"
to be as follows, that is to say :-
This Invention relates principally to the application to steam boilers
of improved outlet valves acting with proportionally reduced pressures,
whereby diminished liability to derangement and increased safety are
obtained.
In one arrangement which is to be substituted for the ordinary safety
valve, the steam from the boiler has access in the first instance by one

page_text: or more pipes or passages to what will herein be termed a proportional
reducing valve chamber, entering such chamber by one or more inlet
ports in a port face which is also formed with one or more outlet ports
leading by one or more pipes or passages to the atmosphere. These
inlet and outlet ports are in the same or in parallel planes, and are
ordinarily closed by one plate or valve which is kept on its scat by the
pressure of the steam in the chamber; such pressure being in a certain
proportion less than the boiler pressure, as it has to resist the boiler
pressure against only a part of the under surface of the valve, and as
against another part of such under surface there is only the atmospheric
pressure (acting in the same direction as the boiler pressure). The
proportion the pressure in the chamber will bear to that in the boiler
will obviously depend on the relative areas of the inlet and outlet ports.
One or more common safety valves of a comparatively very small size
are fitted to the chamber, and are loaded to a pressure below the
intended limit for the boiler pressure, and in the proportion thereto
that the areas of the internal inlet and outlet ports are arranged for.
If it is wished to blow off steam at a pressure below the limit, either
the small safety valves may be cased in the ordinary way, or the
pressure in the chamber may be reduced by opening a stop-cock on
a small pipe which may be led from the chamber to the engine room,
or any other locality. The main internal valve must of course lift
whenever the pressure in the chamber is reduced below what is pro-
portional to the actual boiler pressure. The small safety valves prevent
the pressure in the chamber becoming too great, whilst the main
internal valve acts as a proportional reducing valve to keep up
sufficient pressure in the chamber, as on this being lower than what
corresponds to the boiler pressure the main valve lifts just sufficiently
to admit the requisite supplement of steam into the chamber.
The second arrangement of valve comprised in the Invention is for
controlling the outlet of steam from a boiler in an improved manner,
when the steam passing out is required to be of a pressure proportionally
reduced from that in the boiler.
In one modification an ordinary conical seated valve is connected by a
spindle to a piston working in a cylindrical recess in the valve chamber,
with the outer side of the piston in communication with the atmosphere
or a condenser. The piston is made proportionally smaller than the
valve, and the boiler pressure being admitted between them opens the

page_text: valve only until sufficient steam passes to make up the desired lower
pressure in the space or pipe beyond the valve.
In a second modification the piston is a fixture, and the valve is
made with a cylindrical cavity to work on the piston, but the action
is the same.
In both modifications the piston and cavity in which it works are
by preference of the same length.
The third arrangement of valve comprised in this Invention is a
safety stop valve to be applied to the main or other steam pipe leading
from a boiler to engines or other apparatus, and is designed to admit
of the steam being shut off much more rapidly than is possible by
ordinary screw gear when the steam pipe or other part of the apparatus
is ruptured.
The valve is constructed like either of the two modifications hercin-
before described as forming the second arrangement, but with the piston
larger in area than the valve and not open to the atmosphere. The
cavity in which the piston works is ordinarily filled with steam which
keeps the valve open, but a pipe is led from it to the engine room,
or other convenient locality, and on a stop-cock on this pipe being
opened the pressure in the cavity is relieved, and the pressure on
the other side of the piston causes the instant closing of the valve.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Weir and James Weir in the Great Seal
Patent Office on the 11th December 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, GEORGE
WEIR, of Glasgow, in the County of Lanark, North Britain, Engineer,
and JAMES WEIR, of Liverpool, in the County of Lancaster, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of Junc, 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 us, the said George Weir and James Weir, Her special

page_text: licence that we, the said George Weir and James Weir, our executors,
administrators, and assigns, or such others as we, the said George Weir
and James Weir, our 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 In-
vention for "IMPROVEMENTS IN SAFETY AND OTHER OUTLET VALVES FOR STEAM
BOILERS," upon the condition (amongst others) that we, the said George
Weir and James Weir, our executors or administrators, by an instru-
ment in writing under our, 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 we, the said George Weir and James Weir, do
hereby declare the nature of our 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, reference being had to the
accompanying Drawings, that is to say:-
Our said Invention relates principally to the application to steam
boilers of improved outlet valves acting with proportionally reduced
pressures, whereby diminished liability to derangement and increased
safety are obtained.
And in order that our said Invention and the manner of performing
the same may be properly understood, we hereunto append a Sheet of
explanatory Drawings to be herein-after referred to, and representing
various modifications of our improved valves. In these Drawings the
same reference numerals are used to mark the same or like parts
wherever they are repeated.
Figure 1 is a vertical section of one modification of our improved
valve which is to be substituted for the ordinary safety valve. In this
modification the steam from the boiler has access in the first instance
by one or more pipes or passages 1 to what will herein be termed a
proportional reducing valve chamber 2, entering such chamber by one
or more inlet ports 3 in a port face 4, which is also formed with onc

page_text: or more outlet ports 5 leading by one or more waste pipes or passages 6
to the atmosphere. In the example shown in Figure 1 there is one
outlet port 5 which is in a circular form, and there is one inlet port 3
which is in an annular form encircling the outlet port 5. The inlet
and outlet ports are shown as being in the same plane, but they might
be in different planes parallel to each other. These inlet and outlet
ports 3, 5, are ordinarily closed by one plate or valve 7 which is kept
down on its seat, that is, on the port face 4 by the pressure of the steam
in the chamber 2, such pressure being in a certain proportion less than
the boiler pressure, as it has to resist the boiler pressure against only
a part of the under surface of the valve 7, namely, that part of the
surface immediately over the inlet port 3, and as against another part
of such under surface, namely, that over the outlet port 5, there is only
the atmospheric pressure (acting in the same direction as the boiler
pressure). The proportion that the pressure in the chamber 2 should
bear to a given boiler pressure will obviously depend on and is easily
calculable from the relative areas of the inlet and outlet ports 3, 5.
Figure 2 is a vertical section of a modification which we prefer to
adopt in the case of comparatively large safety valves. In it the port
face 4 and valve 7 are made of brass, the inlet port 3 is placed centrally
with the outlet port 5 encircling it in an annular form, both ports being
crossed by radial feathers for connecting and strengthening the parts,
as will be understood from Figure 3, which is a plan of the port face 4.
The valve 7 is made hollow, as shown in Figure 2, to give access to
the steam from the inlet 5 to the outer edge of the valve, so that when
the valve lifts a quantity of the steam from the boiler may get into the
chamber 2, sufficient for maintaining the proper pressure in that
chamber. There is an annular opening 8 in the face of the valve
near the edge for the steam to pass out by, but an angular ridge is
formed on the port face 4 extending a little into this annular opening 8
to regulate the egress of the steam into the chamber 2 as the valve
rises. The pressure in the proportional reducing valve chamber 2 is
regulated by means of an outlet 9 therefrom, through which outlet
steam can escape whenever the pressure in the chamber becomes from
any cause greater than the pressure which is in the proper proportion
lower than the highest boiler pressure at which it is intended the main
valve 7 shall remain shut. Should the pressure in the chamber 2
become too low from any cause it is obvious that the main valve 7

page_text: must rise, which will allow of as much steam entering the chamber 2
as will make up its proper pressure. The main valve 7 itself thus
acts as a proportional reducing valve for supplying the chamber 2.
The outlet 9 from the proportional reducing valve chamber 2 is con-
trolled by a common safety valve 10 loaded with a weighted lever
or with a direct or dead weight 11 to the proper lower pressure. This
subsidiary valve 10 is not only much less in area than the main boiler
outlet passage 1, but also requires a less load per square inch (as already
stated), and on account of these features the combined arrangement is
extremely well suited for marine boilers, in connection with which it
has for some time been a great desideratum to dispense if possible with
the heavy weights required for ordinary safety valves. Handles 12, 13,
are provided in connection with the valves 10 and 7 (the one for the
latter passing through a stuffing box), whereby the valves can be turned
round on their seats to make sure at any time that they are not sticking.
The valve 7 (Figure 2) is kept from deviating laterally from its position
by being made with a spindle which works in an eye in the centre of
the port face 4, but in the simpler modification, Figure 1, the valve is
kept central by a double bow of thin flexible metal connected by pins
to it and to the top of the chamber 2.
Two or more small safety valves (10) may be applied to the pro-
portional reducing valve chamber to diminish the risk (if any exists)
of the pressure in the chamber becoming too great; or there may be
applied in connection with the chamber 2 instead of or in addition to
the common safety valve 10, a mercurial appliance for which Letters
Patent have been applied for by James Weir, one of the present
Patentees on 18th November 1872 (No. 3436).
If it is wished to blow off steam at a pressure below that for which
the parts are loaded or proportioned, this may be done by easing the
small valve 10 in the ordinary way, or by opening a stop-cock 14 in
communication with the proportional reducing valve chamber 2, and
this easing cock may be on a pipe which is led from the valve chamber 2
to the engine room of a ship, or to any other convenient locality.
The second arrangement of valve comprised in our Invention is for
controlling the outlet of steam from a boiler in an improved manner,
when the steam passing out is required to be of a pressure proportionally
reduced below that in the boiler.

page_text: In one modification, which is shown in vertical section in Figure 4,
an ordinary conïcal seated valve 15 is connected by a spindle 16 to a
piston or plunger 17 working in a cylindrical recess 18 in the valve
chamber, with the outer side of the piston 17 in communication with the
atmosphere or with a condenser by a pipe 19. The piston 17 is made
proportionally smaller than the valve 15, and the boiler pressure
entering between them by the inlet 20 opens the valve 15 only so
far as to allow sufficient steam to pass to make up the desired lower
pressure in the space or pipe 21 beyond the valve 15. The valve
spindle 16 is connected to the piston 17 by a ball-and-socket joint,
to allow of the valve accommodating itself to any slight want of
parallelism caused by unequal expansion. The socket part of the
joint is made in two halves over which a thimble 22 is slipped to
bind them together. Also to prevent derangement from inequality
of expansion the cylindrical part of the piston is made thin and
deep as well as the cylinder 18 in which it works.
In a second modification, which is shown in vertical section in
Figure 5, the piston 17 is a fixture, and the valve 15 is made with a
cylindrical cavity 18 to work on the piston 17, but the action is the
same as in the previously described modification. Figure 6 is a plan
of the parts as with the upper part of the casing and the valve 15
removed. The piston 17 is formed on a disc piece 23 held between
the upper and lower parts of the casing, and the communication 19
with the atmosphere is made through the neck of the piston, and
through the disc piece. The steam from the boiler enters below at 20,
and passes up by openings in the disc piece 23 to the under side of the
valve 15.
In both modifications the piston 17 and cavity 18 in which it works
are by preference both of the same length.
The third arrangement of valve comprised in our Invention is a
safety stop valve to be applied to the main or other steam pipe leading
from a boiler to engines or other apparatus, and is designed to admit
of the steam being shut off much more rapidly than is possible by
ordinary screw gear when the steam pipe or other part of the apparatus
is ruptured.
The valve is constructed like either of the two modifications shown

page_text: in Figure 7, but the piston 17 is made larger in area than the valve 15,
and the cavity 18 in which it works is not open to the atmosphere.
This cavity 18 is ordinarily filled with steam which leaks past the
piston 17 and which keeps the valve open, but a pipe 24 is led from it
to the engine room or other convenient locality, and on a stop-cock on 5
this pipe being opened the pressure below the piston 17 is relieved, and
the pressure on the upper side then causes the instant closing of the
valve 15.
Having thus particularly described our said Invention, and the
manner in which the same is to be performed, we have to state 1
that we do not restrict ourselves to the precise details herein described
or delineated; but that what we believe to be novel and original, and
claim as the Invention secured to us by the herein-before in part recited
Letters Patent is,―
1. The application as a safety valve to steam boilers of a plate or lå
valve acted upon by a reduced pressure in a chamber or casing, and
arranged by the same movement to close both the inlet from the boiler
into the chamber or casing and the outlet therefrom to the atmosphere,
substantially as herein-before described.
2. The constructing of proportional reducing valves, substantially in 20
the improved manner herein-before described with reference to Figures
4, 5, 6, on the accompanying Drawings.
3. The constructing of stop valves, substantially in the improved
manner herein-before described with reference to Figure 7 on the
accompanying Drawings.
In witness whercof, we, the said George Weir and the said James
Weir, have hereunto set our hands and scals, this Tenth day of
December, in the year of our Lord One thousand eight hundred
and seventy-two.
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