CERTAIN IMPROVEMENTS IN FLUID SAFETY GUAGES FOR STEAM BOILERS AND OTHER PRESSURE AND VACUUM VESSELS
Year: 1867

page_text: LETTERS PATENT to John Marshall, of Trafalgar Road East, Greenwich,
in the County of Kent, Civil and Mechanical Engineer, for the Invention
of "CERTAIN IMPROVEMENTS IN FLUID SAFETY GUAGES FOR STEAM BOILERS
AND OTHER PRESSURE AND VACUUM VESSELS."
Sealed the 16th August 1867, and dated the 25th February 1867.
PROVISIONAL SPECIFICATION left by the said John Marshall at the
Office of the Commissioners of Patents, with bis Petition, on the
25th February 1867.
'
I, JOHN MARSHALL, of Trafalgar Road East, Greenwich, in the County of
Kent, Civil and Mechanical Engineer, do hereby declare the nature of the
said Invention for "CERTAIN IMPROVEMENTS IN FLUID SAFETY GUAGES FOR STEAM
BOILERS AND OTHER PRESSURE OR VACUUM VESSELS," to be as follows:-
My Invention has reference to an improved guage for steam boilers and
other vessels where fluids are employed either above or below the atmospheric
pressure by means of which, in the event of the guage glass or indicating
receptacle breaking or being broken, no escape of steam, air, or fluid shall
take place further than that contained within the said guage or indicator
itself; I have therefore termed it an "improved fluid safety guage."
"
My Invention is applicable either to existing ordinary water guages or to
new improved fluid safety guages specially constructed for the purpose.

page_text: Firstly, as regards the new fluid safety guage.-The apparatus consists of
two cocks (instead of three as in the old system) and an indicating recep-
tacle, by preference a glass tube, the whole fixed as closely as possible to the
boiler, one cock being for liquids and the other for steam or air..
The water cock consists of a conical plug retained in its seating by a gland;
this plug is bored centrally from its smaller end nearly through its entire length;
at the inner end of this passage a hole is bored right through the plug, and
another hole at right angles to the same, thus forming three outlets to the
said longitudinal passage. The shell of the cock has one passage way bored
vertically through it, one end opening downwards and outwards and the other
end opening to a chamber formed upon the shell; within this chamber a
spindle or other valve is fitted working in guides or otherwise; the top of the
chamber is closed with a plug, and between the plug and valve a passage is
formed laterally leading into another chamber with a gland for holding the
guage glass or indicating receptacle.
The steam cock consists of a conical plug constructed and bored longi-
tudinally, as before described for the water cock, but instead of a hole being
bored right through the plug two holes are bored at right angles to each other,
and meeting the inner end of the longitudinal passage. The shell has a chamber
formed upon it with valve and fittings, as before described for the water cock,
having a passage bored out underneath the valve to meet the plug leading out
of the passage way from the valve chamber to the chamber for holding the
guage glass or indicating receptacle. A communication or secondary passage is
formed which enters the shell of the cock at right angles to the passage bored
out underneath the valve. In working this guage the water is admitted from
the boiler along the longitudinal passage in the conical plug up through the right
angled passage
in the same to the under side of the valve, thence past the open
valve through the communicating passage into the chamber holding one end
of the guage glass or indicating receptacle. The steam is admitted in the longi-
tudinal passage in the conical plug, thence through one of the right-angled
passages in the same to the under side of the valve, and past the open valve
through the communicating passage into the chamber holding the other end of
the guage glass or indicating receptacle. In the event of the guage glass or
indicating receptacle breaking or being broken the water striking forcibly
against the under surface of the valve (otherwise retained open by its own specific
gravity) drives the valve home to its seat, and retains it there by the pressure
in the boiler. So likewise is the action and effect of the steam upon the valve
at the opposite end of the guage glass or indicating receptacle. To "blow off"
water turn the water cock round either to the right hand or to the left,

page_text: when the water has immediate escape downwards through the hole already
described as being bored in the shell; by this action the valve of the steam
cock forthwith closes, allowing no further escape of steam than that contained
in the guage glass or indicating receptacle. To "blow off" steam as well as
water turn the steam cock round either way, when the steam passes through
the secondary passage clear of the valve & thence through the guage glass,
past the valve of the water, and out along with the water. If required to
"blow off" steam independently of water it may be effected by varying the
direction of the passage in the shell of the water cock communicating with
the conical plug and the." blow off" outlet, but such is seldom, if ever, found
necessary in practice.
In constructing fluid indicator for vacuum purposes it is only necessary to
alter the positions of the steam and water cocks from beneath the valves to
above them, and the communications from the valve chambers to the guage
glass or indicating receptacle from above to beneath the saine.
In con-
structing fluid indicators for such vacuum purposes as the condensers of
engines were the same are below a. convenient visible height or the working
platform, the water cock is fixed near the bottom of the condenser, and a pipe
or tube is carried from the top of the said condenser to a sufficient height
above the platform to be readily visible; to the upper end of this tube is fixed i
the steam cock, and from the steam to the water cocks is carried an indi-
cating tube properly protected; within this tube a float rests upon the surface
of the liquid, from which one or more slight suspension chains or cords pass
up through a counterbalance over one or more small pullies back to the same,
so that as the float rises or falls with the rise or fall of the liquid in the
condenser the level is indicated by the counterbalance at the visible point.
Secondly, as regards the application of my improvements to existing ordinary
water guages.
The water cock. I take out the gland for packing the guage glass and
in place thereof screw in a chamber containing a spindle, or other valve rising
upwards, similar to that described under the head of the "new fluid safety
guages," the other end of the said chamber being. fitted with a gland for
packing the glass similar to the gland removed.
The steam cock. I take out the gland for packing the guage glass, and
in place thereof screw in a chamber containing a spindle or other valve
retained upwards by a spring and closing downwards, the other end of the said
chamber being fitted with a gland for packing the glass similar to the gland
removed. On the top of the spindle of this valve I fix a small button; I
next take out the plug used for inserting the guage glass, and in place thereof.

page_text: substitute another plug having through its centre a screw cut of one or more
threads of sufficient pitch to rise about inch in ȧturn; this plug is also
fitted with a stuffing box and gland. A spindle having on one end a curved
forked hook and about its centre a screw cut corresponding to the thread
already described is passed through the plug and packed steam-tight by the
stuffing box and gland; the other end of the spindle is provided with a cross
handle. In inserting the plug with the spindle in it the curved forked hook is
made to take hold of the button of the valve, and then the plug is serewed
down tight in its place.
To blow off water only.-I open the blow-off cock as usual, but to blow
off steam as well as water I turn the cross handle of the curved forked hook
in the plug one-half turn, when the fork catching the button on the valve
lifts the valve from its seat and retains it open against.the pressure of the
steam, allowing the latter to escape past the valve through the guage glass,
and out of the blow-off cock. In this case also in the event of the guage glass
breaking or being broken the pressure immediately closes the valves, and
prevents any escape of steam or water, &c. other than that contained in the
guage glass itself. By this simple means my said improvements can readily:
be applied to existing ordinary water guages without even removing them from
their position in the boiler.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Marshall in the Great Seal Patent Office on the
24th August 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
MARSHALL, of No. 7, Longstone Terrace, Trafalgar Road East, Greenwich,
in the County of Kent, Civil and Mechanical Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of February, in the year of our Lord
One thousand eight hundred and sixty-seven, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Marshall, Her special licence that I, the said John Marshall,
my executors, administrators, and assigns, or such others as I, the said
John Marshall, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time, and at all times there-
after during the term therein expressed should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain and.

page_text: Ireland, the Channel Islands, and Isle of Man, an Invention for "CERTAIN
IMPROVEMENTS IN FLUID SAFETY GUAGES FOR STEAM BOILERS AND OTHER PRESSURE
OR VACUUM VESSELS," upon the condition (amongst others) that I, the said
John Marshall, 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 Marshall, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being bad to the Drawings hereunto annexed, that is to
say:
My Invention has reference to an improved guage (called a "self-acting
fluid safety gauge"), for steam boilers and other vessels where fluids are
employed either above or below the atmospheric pressure, by means of which
in the event of the guage glass or indicating receptacle breaking or being
broken, no escape of steam, fluid, or air shall take place beyond that contained
within the said glass or indicating receptacle itself.
19
My said Invention is applicable either to existing ordinary "water guages
or to "new improved fluid guages" specially constructed for safety purposes.""
As regards the new "improved fluid safety guage," the apparatus consists.
of two instead of three cocks (as at present) and of an indicating receptacle, by
preference a glass tube as usual, the whole being fixed as closely as possible
to the boiler or other vessel, one cock being for fluids and "blow off" and the
other for steam or air.
:
By reference to the claims it will be seen that my Invention does not consist
of any particular description of valve, neither of any particular action nor
position for the same. I use a "spindle" or other valve, such as the
"spherical," "differential throttle," "butterfly," &c., and I suit the action
whether vértical, horizontal, or inclined to the valve used, and the position;
whether in or about the cock, to the action. I therefore content myself with
describing and illustrating a vertically acting "spindle" valve placed on the
cock, and a horizontally acting "spherical" valve placed within the same as
being sufficient for the purposes of the present Specification of my said Iuven-
tion, whether as regards the new "improved fluid guage" or the application'
of the." safety" principle to existing ordinary "water guages."
Figure 3 represents a front elevation of new "improved fluid safety guage.;"

page_text: Fig. 4, side elevation of same; Fig. 1, section of same on line A, B; Fig. 2,
section on line C, D; Fig. 5, section on line E, F; Fig. 6, plan of valve
guide; Fig. 8, side elevation of converted ordinary "water gauge;" Fig. 7,
side centre section of same; Fig. 9, section of shell and plug of cock shewing
"spherical" valve description, and arrangement.
The water cock consists of a conical plug A, Figs. 1, 2, 3, and 4, retained
in its seating by a gland B, Figs. 1, 2, 3, and 4. This plug is bored centrally
from its smaller end nearly through its entire length, the passage being after-
wards plugged at the smaller end. At the inner end of this passage a hole C,
Figs. 1 and 2, is bored right through the plug, and also another hole D,
Figs. 1 and 2, at right angles to the same, thus forming three outlets to the
said longitudinal passage. At the smaller end of the plug A two other holes
E and F, Figs. 1 and 5, are bored at right angles to one another, and forming
inlets into the first-named longitudinal passage. The passage from the
boiler G, Figs. 1 and 5, meets the conical plug at right angles into the
passages E and F, Figs. 1 and 5. The shell of the cock has one passage way
bored vertically through it, one end opening downwards and outwards, forming
the "blow-off" outlet H, Figs. 1 and 2, and the other end opening upwards
into a chamber formed upon the said shell. Within this chamber is a valve
box I, Figs. 1 and 2, containing a spindle valve K, Figs. 1 and 2, held firmly
in its place by the plug nut L, Figs. 1 and 2. Between the valve and the
plug nut a passage M, Figs. 1 and 2 is formed laterally, leading into another
chamber N, Figs. 1 and 2, serving to hold the gland for packing the guage glass.
The steam cock consists of a conical plug O, Figs. 1 and 2, constructed
and bored longitudinally as before described for the water cock, but instead
of a hole being bored right through the plug, two holes P and Q, Figs. 1 and 2,
are bored at right angles to each other, and meeting at the inner end of the
longitudinal passage. The shell of the cock has a chamber formed upon it
with valve and fittings as before described for the water cock, having at its
lower end a hole bored out to meet the plug leading out of the passage way R,
Figs. 1 and 2, from the valve chamber to the chamber S, Fig. 2; for holding
the guage glass a communication or secondary passage T, Fig. 2, is formed,
which enters the shell of the cock at right angles to the passage bored out
underneath the valve.
I do not confine myself precisely to the above minute details of construction
for the water and steam cocks, as in certain cases it might be desirable to vary
them to some trifling extent.
In the following description for working this guage, corresponding letters
represent the same parts in Figs. 1, 2, 3, 4, and 5.

page_text: When the handle is downwards or in the position "safety," indicated on
the diagram of the water cock, the water is admitted from the boiler through
the passage
G down through the passage E, along the longitudinal passage A,
thence up through the vertical passage D into the valve chamber I, passing
round the valve K, and finally through the passage M into the guage glass.
When the handle is downwards or in the position "safety" indicated in the
diagram of the steam cock, the steam is admitted from the boiler through
the longitudinal passage in the plug O, up through the vertical passage P,
thence into the valve chamber and round the valve as described for the water,
and finally through the passage R into the guage glass. Thus in the event
of the guage glass breaking or being broken the valves otherwise kept open
by their specific gravity are driven by the force of the water and steam against
their seatings, and retained there during the existence of any pressure in the
boiler or other vessel. To "blow off" water only turn the steam cock turn
to the left so as to shut the steam off as indicated on the diagram "shut off,"
then turn the water cock turn to the left also as indicated by "blow-off
steam and water," when the water from the boiler passes through the passages
G and F along the longitudinal passage in the plug, and thence through C
out at the blow-off II. To "blow off" steam only, turn the steam cock turn
to the right as indicated by "blow off steam" in the diagram, the steam then
passes through the longitudinal passage in the plug through the passage P,
thence up through the secondary passage T, passing clear of the valve into the
guage glass, then turn the water cock turn to the right, when all communi-
cation between the water and the glass being shut off, and opened between
the blow-off outlet and the valve chamber of the water cock, the steam rushes
through the guage glass, through the valve chamber of the water cock, and
thence out at the blow off. To "blow off" steam and water leave the handle
of the steam cock in the position as last described, and turn the handle of
the water cock turn to the left in the position first described for blowing
off water only, when all passages of communication being fully opened an
immediate rush of both steam and water takes place. To "shut all off" turn
the bandle of the steam cock turn to the left, and the bandle of the water
cock upside down as indicated by "shut off" on the diagrams.
As regards the application of my improved "safety" principle to existing
ordinary "water guages," I first take out the ordinary glass packing glands A
and B, Fig. 7, and in place thereof screw in valve chambers C and D, Fig. 7,
containing spindle valves E and F, Fig. 7, and then replace the old glands in the
new chambers. Underneath the steam valve F I fix a spring to keep the valve
against its specific gravity, and instead of the ordinary cap I use a new cap,

page_text: having a spindle G with a cross handle and a double-threaded screw cut upon
it, and fitted with a packing gland. Attached to the lower end of this spindle
is a curved forked hook catching under a button formed on the valve spindle.
In working this "converted guage" to "blow off" water only, I open the
blow-off cock as usual, but to "blow off" steam and water I simply turn the
cross handle turn round, when the forked book catching the button on the
valve spindle lifts the valve from its seat, and retains its open against the pres-
sure of the steam, allowing the latter to escape past the valve through the
glass and out at the blow-off cock. In this case also in the event of the guage
glass breaking or being broken the pressure immediately closes the valves,
and prevents any escape of water or steam other than that contained in the
glass itself.
As regards another description of application of my "improved safety"
principle to existing ordinary "water guages" applicable also to (specially
constructed new "fluid guages") I simply take out the ordinary plugs of the
water and steam cocks, of which a section of shell and plug is shewn at
A, Fig. 9. I then bore out the water and steam ways so as to form a conical
seating at one end, as shewn at B, and insert a metallic or other ball or "pea'
of sufficient diameter to rest upon the seating B. At the other end of the
enlarged steam and water ways I insert a piece of metal C, bored out through
its centre to the same diameter as the original water and steam ways. A
portion of its external diameter next the "pea" is then turned down to about
half its thickness, and through this reduced part apertures are made from the
outside into the centre hole. The plug is finally re-ground and fitted back
into its place. Upon the pressure of the steam or water (the glass being
broken), passing in the direction of the large arrow the "pea" is driven
firm home to its seating, thereby closing both steam and water ways against
the escape of either. For the purpose of "blowing through" turn the handle D
of the plug A upside down, when the positions of the steam and water ways
being reversed against the pressure the ball or "pea is driven against the
perforated seat, allowing the steam or water to escape round the "pea" through
the perforations in the direction of the curved arrows, and thence freely out at
the blow off.
.
In constructing "fluid safety" indicators or guages for vacuum purposes, it
is only necessary to alter the positions of the steam and water-cocks from
beneath the valves to above them, and of the communications from the valve
chambers to the glass from above to beneath the same. In constructing these
indicators or guages however for such vacuum purposes, as the condensers of
marine and other steam engines where the same are below a convenient visible

page_text: height or the working platform, the water cock is placed near the bottom of
the condenser, and a pipe or tube is carried from the top of the said condenser
to a sufficient height above the platform to be readily visible. To the upper
end of this tube is fixed the air cock (corresponding to the steam cock described
(for the "fluid safety guages"), and from the air to the water cocks is carried
a glass indicating tube, metal protected, or a tube composed partly of glass and
partly of metal. Within this tube a float rests upon the surface of the liquid,
from which one or more slight suspension chains or cords pass up through a
counterbalance over one or more small pulleys back to the same, or a simple
float carrying an indicating rod in communication with an index would suffice,.
so that as the float rises or falls with the rise or fall of the liquid in the
condenser, the level is always indicated by the counterbalance or indicating
rod at the visible point. This application of my Invention is at once so simple
and self evident that a Drawing is not necessary to illustrate the same.
Having now described the nature of my Invention, and in what manner the
same is to be performed, I declare that I claim as my Invention,-
Firstly, the many way guage cock producing the varied effects required as
the various ways are opened or shut off from one another as described.
Secondly, the use of two guage cocks instead of three, and the mode or
method of working the same, as herein-before set forth and shewn.
Thirdly, the conversion of existing ordinary "water guages" into " fluid
safety guages" by means of spindle or other valves (whatsoever their action
and position) in communication with the steam and water outlets of said
guages.
Fourthly, the application of the "improved safety" principle by the reverse
action of the valves and communications to the cocks of vacuum vessels.
And, fifthly, the application of the same principle to the condensers of
marine and other steam engines when situated below the working platform,
whereby the level of the liquid in the condenser is indicated at a visible height,
both as herein-before described.
In witness whereof, I, the said John Marshall, have hereunto set my
hand and seal, this Twenty-fourth day of August, in the year of
our Lord One thousand eight hundred and sixty-seven.
JOHN MARSHALL. (L.B.)