IMPROVEMENTS IN APPARATUS TO BE USED AS A SAFETY VALVE OR IN CONNECTION WITH OTHER SAFETY VALVES
Year: 1872

page_text: LETTERS PATENT to James Weir, of Liverpool, in the County of
Lancaster, Engineer, for the Invention of "IMPROVEMENTS IN
APPARATUS TO BE USED AS A SAFETY VALVE OR IN CONNECTION WITH OTHER
SAFETY VALVES."
Scaled the 24th January 1873, and dated the 18th November 1872.
PROVISIONAL SPECIFICATION left by the said James Weir at the
Office of the Commissioners of Patents, with his Petition, on the
18th November 1872.
I, JAMES WEIR, of Liverpool, in the County of Lancaster, Engineer,
5 do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN APPARATUS TO BE USED AS A SAFETY VALVE OR IN CONNECTION WITH OTHER
SAFETY VALVES," to be as follows, that is to say :-
This Invention relates to improved apparatus to be used as a safety
valve, or as is preferred in connection with other safety valves, and is

page_text: more particularly designed to be used in connection with safety valves
of the improved kind described in the Provisional Specification, lodged
with an application for Letters Patent by George Weir and the present
applicant, and dated 12th June 1872 (No. 1773).
°
In one modification of the improved apparatus there are three vertical
tubes in communication with each other at the bottom, and herein-after
termed respectively the reservoir tube, the valve tube, and the return
tube. The lower part of the valve tube is enlarged, and the upper part
projects or dips down into it, whilst the top of the enlargement has a
side pipe communicating with it to admit steam or other fluid either
directly from a boiler or as is preferred from a proportional reducing
valve in connection with a boiler. The top of the valve tube projects
up into what may be termed an outlet and return vessel, and the bottom
of which communicates with the return tube. The top of the reservoir
tube communicates with the bottom of a vessel acting as a reservoir.
Mercury is put into the reservoir and fills all three tubes when the
steam or fluid admitted to the enlargement of the valve tube is not of
a greater than atmospheric pressure, but as the pressure increases it
depresses the mercury in the enlargement until the bottom end of the
dipping tube is uncovered, and the steam or fluid then carries up and
out of the dipping tube what mercury is in it, and thus gains access to
the outlet and return vessel. The mercury thus carried up finds its way
back by the return tube.
The steam or fluid may be allowed to escape from the outlet vessel by
an opening, pipe, or whistle. It is however preferred to lead it by a pipe
to a cylinder or vessel with a piston or diaphragm, and to connect such
piston or diaphragm with the cock of a whistle, or with an outlet valve
for letting off steam in quantity from the boiler, or with the lever or
load on an ordinary safety valve, so that it may either sound an alarm
or act automatically in relieving the boiler. If the dipping part of the
valve tube is made large enough the mercury can return down through
it, notwithstanding that the steam passes up, and the third or return
tube may be dispensed with. The pressure which the steam or fluid
must reach to get egress will be measured by the vertical distance
between the bottom of the dipping tube and the level of the mercury
in the reservoir when the mercury in the valve tube is depressed just
down to the bottom of the dipping tube, and may therefore be made

page_text: greater or less by giving suitable lengths to the several tubes. In cases
where a sufficient vertical length of tube can be conveniently obtained
water or other suitable liquid may be substituted for the mercury.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Weir in the Great Seal Patent Office on
the 16th May 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
WEIR, of Liverpool, in the Connty of Lancaster, Engincer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of November, in the
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 successors,
give and grant unto me, the said James Weir, Her special licence that I,
the said James Weir, my executors, administrators, and assigns, or such
others as I, the said James Weir, 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 APPARATUS TO BE
USED AS A SAPETY VALVE OR IN CONNECTION WITH OTHER SAFETY VALVES,"
upon the condition (amongst others) that I, the said James Weir,
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 James Weir, 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

page_text: following statement in writing, reference being had to the accompanying
Drawings, that is to say:-
My said Invention relates to improved apparatus to be used as a
safety valve, or as I prefer in connection with other safety valves, and
is more particularly designed to be used in connection with safety t
valves of the improved kind described in the Specification of Letters
Patent granted to George Weir and myself, and dated 12 June 1872
(No. 1773).
And in order that my said Invention and the manner of performing
the same may be properly understood, I hercunto append two Sheets of
explanatory Drawings to be herein-after referred to, and representing
two modifications of my improved apparatus. In these Drawings the
same reference letters and numerals are used to mark the same or like
parts wherever they are repeated.
Figures 1 and 2 on Sheet 1 of the Drawings are a vertical and a 1
horizontal section of one modification, in which there are three vertical
tubes in communication with each other at the bottom, and herein-after
termed respectively the reservoir tube a, the valve tube b, and the return
tube c.
The lower part of the valve tube b is enlarged or fitted into a
cast-iron bulb e, and the upper part d projects or dips down into it,
whilst the top of the enlargement e has a side pipef communicating
with it to admit steam or other fluid either directly from a boiler or as
I prefer from a proportional reducing valve in connection with a boiler.
The top of the valve tube communicates with what may be termed an
outlet and return vessel g, and the bottom of which communicates with
the return tube c. The tube communicates with the vessel g, which
is circular, by a tangential opening, so that mercury entering will have
a whirling motion, which will facilitate the separation of the steam from
it. The communication of the tube c is also tangential to facilitate the
entrance into it of the whirling mercury, and is at a lower level than
the entrance. The top of the reservoir tube communicates with the
bottom of a vessel h acting as a reservoir. Mercury is poured into the
reservoir and fills all three tubes when the steam or fluid admitted to
the enlargement e of the valve tube b is not of a greater than atmospheric
pressure, but as the steam pressure increases it depresses the mercury
in the enlargement until the bottom end of the dipping tube dis
uncovered, and the steam then carries up and out of the dipping tube d

page_text: what mercury is in it, and thus gains access to the outlet and return
vessel g. The mercury thus carried up finds its way back by the return
tube c.
The steam may be allowed to escape from the outlet vessel g by an
opening, by a pipe, or by a whistle. I however prefer to lead it by a
pipe to a cylinder or vessel k (shown in section in Figure 3) with a
piston m or a diaphragm, and to connect the rod n of such piston or
diaphragm with the cock of a whistle or with an outlet valve p for
letting off steam in quantity from the boiler, or with the lever or load
on an ordinary safety valve, so that it may either sound an alarm or act
automatically in relieving the boiler. If the dipping part d of the valve
tube b is made large enough the mercury can return down through it,
notwithstanding that the steam passes up, and the third or return tube c
may be dispensed with. The pressure which the steam or fluid must
reach to get egress will be measured by the vertical distance between
the bottom of the dipping tube d and the level of the mercury in the
reservoir h, when the mercury in the valve tube b is depressed just
down to the bottom of the dipping tube d and may therefore be made
greater or less by giving suitable lengths to the several tubes. In cases
where a sufficient vertical length of tube can be conveniently obtained
water or other suitable liquid may be substituted for the mercury.
On Sheet 2 of the Drawings my improved apparatus is shown as
combined with a steam loaded safety valve of the kind described in the
carlier Specification herein-before referred to. Figure 4 is a vertical
section of the mercurial alarm apparatus; and Figures 5, 6, 7, are a
vertical section, an elevation, and a plan of the safety valve details in
connection with it. In this apparatus the steam from the boiler has
access by a passage 1 to an annular port 2, in what is termed a pro-
portional chamber 3, and in the same face as the port 2 there is con-
centrically within that port a circular port 4, which leads by the
passage 5 to the atmosphere. The ports 2, 4, are covered by
a disc
valve 6 constituting the main safety valve, and this valve is necessarily
kept down on the port face whenever the total effective pressure on the
top of it is however little in excess of the pressures acting upwards
against its under sides in the ports 2, 4. The pressure per square inch
in one part being that of the boiler, and in the other that of the
atmosphere; the pressure on the top of the valve to balance these must

page_text: c+d
obviously be an intermediate pressure and therefore less than the boiler
pressure. If the pressures in the ports 2, 4, are in pounds and a and
the effective areas of the ports in square inches d and c respectively
then the balancing pressure above must obviously be per square
(axc)+(bxd)
inch
pounds. The pressure in the chamber 3 is pre-
vented from exceeding the proper proportional pressure by a comparatively
small valve 7 loaded by a spring, dead weight, or weighted lever, to
correspond to the said proportional lower pressure, whilst the lifting of
the main valve 1 itself will admit to the proportional chamber 3 the
steam that may at any time be required to make the pressure therein
to the proper amount. A handled rod 8 entering through a stuffing box
is provided for turning the main valve 6 at any time in the event of any
dirt sticking on the face, but this rod cannot be forced down on the
valve. The load on the valve 7 may be varied, but when the apparatus
has combined with it the mercurial alarm it will be impossible to
maintain in the proportional chamber 3 a greater pressure than that for
which the mercurial alarm is constructed.
up
The safety valve apparatus communicates with the mercurial alarm
by a pipe 9 proceeding from the proportional chamber 3 and leading
into a chamber 10, into which is fixed the upper end of a tube 11. The
tube 11 communicates at its lower end with two tubes 12, 13, the former
leading into a small open reservoir 14, and the latter into a chamber 15
formed in the same casting as the chamber 10. Mercury is filled into
the tubes 11, 12, 13, by means of the reservoir 14, and when steam is
on the apparatus it forces down the mercury in the tube 11 in proportion
to its pressure just as in a common mercury gauge. As the pressure
increases the mercury is more and more forced through the tube 12 out
into the reservoir 14, until the mercury is depressed below the bottom
of the tube 11, whereupon the steam gets access by the tube 13 to the
chamber 15. This chamber 15 is closed by a flexible diaphragm 16
having in connection with it a rod 17, which on being pressed outwards
opens a valve 18 in a steam pipe 19 in direct communication with the
boiler.
The steam pipe 19 has a branch 20 leading to an alarm whistle 21,
and another branch leading to a relieving valve of the kind shown in
T
1 Ը...]
connection with the proportional chamber 3 of

page_text: the main safety valve, or in direct connection with the boiler. A small
relief cock 24 is provided in connection with the chamber 15 for, if
necessary, reducing the pressure therein, so as to allow of the valve 18
closing after an alarm has been attended to, and the steam in the boiler
reduced to the proper pressure. The pressure at which the alarm will
sound will depend on the height of the column of mercury in the tube 12
above the bottom of the tubes 11, 13, and the tubes may be made of
lengths to suit any intended pressure.
In order that the effective height of the mercury may not be altered
by the rolling of a ship the casting with the chambers 10, 15, and having
the tubes 11, 12, 13, attached to it is mounted on journals 25, 26, so that
the tubes may always hang a plumb.
In applying my improved mercurial apparatus in connection with an
ordinary safety valve steam of a less pressure than that in the boiler
may be provided for acting in it, by making the communication between
the boiler and the steam inlet f of the apparatus through a loaded
valve in a chamber. In cases however in which the boiler pressure
is not great and a mercurial column of a sufficient length can be con-
veniently obtained the full boiler pressure may be admitted to the
apparatus.
Having thus particularly described my said Invention, and the manner
of performing the same, I have to state that I do not restrict myself to
the precise details herein described or delineated, but that what I believe
to be novel and original, and claim as the Invention secured to me by
the herein-before in part recited Letters Patent is,―
1. The arranging or combining together of the parts of apparatus to
be used as a safety valve, with a column of mercury or other suitable
liquid acting as a valve, and with provision for the return of the mercury
or other liquid after its displacement, all substantially as and for the
purposes herein-before described.
2. The using of the mercurial or liquid column as a valve to admit
steam to actuate alarm or relief apparatus when a certain pressure is
exceeded, substantially as herein-before described. .
3. The combining of a mercurial or liquid column acting as a safety

page_text: valve with a reducing valve or other safety valve interposed between it
and the boiler, substantially as herein-before described.
In witness whereof, I, the said James Weir, have hereunto set my
hand and seal, this Fifteenth day of May, in the year of our Lord
One thousand eight hundred and seventy-three.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JAMES WEIR. (L.S.)