IMPROVEMENTS IN STEAM GAUGES
Year: 1868

page_text: LETTERS PATENT to William Edward Newton, of the Office for
Patents, 66, Chancery Lane, in the County of Middlesex, Civil
Engineer, for the Invention of "IMPROVEMENTS IN STEAM GAUGES."—
A communication from abroad by David M. Greene, of Troy, in the
State of New York, United States of America.
Sealed the 2nd June 1868, and dated the 6th February 1868.
PROVISIONAL SPECIFICATION left by the said William Edward
Newton at the Office of the Commissioners of Patents, with his
Petition, on the 6th February 1868.
I, WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery
Lane, in the County of Middlesex, Civil Engineer, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN STEAM Guages,”
to be as follows:-
This Invention consists in a novel construction of steam gauge for
indicating the pressure of steam by means of the temperature or degree
of heat of the steam.
The pressure gauge is formed by combining with a metallic reservoir
or fountain of mercury an exterior steam chamber which surrounds it,

page_text: the steam chamber having a tubular connection with the steam space of
the boiler. The fountain of mercury is attached to the lower extremity
of a glass tube, which has a pressure scale attached thereto, and is
provided at its upper end with a flexible bag to prevent the escape of
the mercury.
The Invention, secondly, consists in forming or graduating the scale of
the pressure gauge by exposing the reservoir of mercury to the action
of steam at a series of temperatures due to pressures determined by a
standard pressure gauge. The pressures are to be marked directly on
the scale. This means of graduating the scale of pressures direct
without making use of thermometric degrees reduced to pressures by
the table, as heretofore suggested obviates liability to crror, and renders
tho pressure gauge so obtained entirely reliable.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said William Edward Newton in the Great Scal
Patent Office on the 5th August 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
EDWARD NEWTON, of the Office for Patents, 60, Chancery Lanc, in the
County of Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria by Her
Letters Patent, bearing date the Sixth day of February, in the year
of our Lord One thousand cight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Edward Newton, Her special
licence that I, the said William Edward Newton, my executors,
administrators, and assigns, or such others as I, the said William
Edward Newton, 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 STEAM GAUGES," being a communication
to me from abroad, upon the condition (amongst others) that I, the
said William Edward Newton, my executors or administrators, by an
instrument in writing. under my, or their, or one of their hands and

page_text: scals, 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 William Edward Newton, 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, reference being had to the Drawing
hercunto annexed, and to the letters and figures marked thereon (that
is to say):-
This Invention consists in a novel construction of steam gauge for
indicating the pressure of steam by means of the temperature or degree
of heat of the steam.
The application of the expansion of mercury by the heat of the
steam within a boiler as a means of indicating the pressure of the
boiler has been heretofore suggested, but it has not been carried into
practice as a steam gauge for want of a practical, substantial, and
certain mode of applying it, and of a proper mode of graduating
pressure gauges acting upon such principle.
This Invention consists in forming a pressure gauge by combining
with a suitable metallic reservoir or fountain of mercury an exterior
steam chamber which surrounds it, the steam chamber having a tubular
connection with the steam space of the boiler. The fountain of mercury
is attached to the lower extremity of a glass tube provided with a
pressure scale attached thereto.
The Invention, secondly, consists in forming or graduating the scale
of the pressure gauge by exposing the reservoir of mercury to the
action of steam at a series of temperatures due to pressures determined
by a standard pressure gauge. The pressures are to be marked directly
on the scale. This means of graduating the scale of pressures direct
without making use of thermometric degrees reduced to pressure by
the table, as heretofore suggested, obviates any liability to error, and
renders the pressure gauge so obtained entirely reliable.
In the accompanying Drawing Fig. 1 is a front elevation, and Fig. 2
a vertical section of one of the improved pressure gauges, which is
constructed as follows:-

page_text: Inside a steam case A is placed a mercury cup B, the latter being
suspended within the former by being screwed into it at the top, as
shewn in Fig. 2, or in any other suitable manner, so as to leave a
space surrounding the cup B within the case. Within the upper end
of the cup B is screwed a plug F, having its lower side or end made
concave, as shown in Fig. 2, and having a hole extending vertically
through it, this hole being enlarged or recessed, as shown, in its upper
part. Into this hole is inserted a glass tube E packed tightly by leather
or other suitable material, as indicated by a, Fig. 2. The packing is
secured in place around the tube E by means of a follower e and an
annular cap h, as represented in Fig. 2, or by any other suitable means,
the object being to so connect the tube E to the cup B as to render
their union tight, and at the same time not break the glass tube.
Behind the tube E is placed a plate D of any suitable material, on
which graduations and figures can be made with ease and distinctness,
and which extends to the top of, or nearly so, and which is secured
firmly in place in such a manner as to hold the top of the tube E
in position and prevent it from being broken. Over the tube and
plate is placed a metallic case C, which may be screwed upon the
projecting portion of the plug F, and thus be held rigidly in place, and
forming a case for the protection of the glass tube and the indicator
plate. This case C is cut away in front, as shown in Fig. 1, so as to
permit the marks and figures on the plate to be readily seen. Over
the open upper end of the tube E a small rubber bag may be tied, as
represented by n in Fig. 2, to prevent the mercury from being spilled,
and also to prevent particles of dirt or dust from getting into the tube.
It has been ascertained by experiment that when the cup B is made
of cast iron or similar metal, and of the thinness that is desirable to
render it very sensitive to the action of the heat, the steam admitted
to the chamber surrounding it will after a time penetrate it more or
less, and becoming condensed within the cup B will form globules of
water therein. To prevent this the exterior surface of the cup B is
covered with a thin coating or sheet of copper, as indicated by the red
line in Fig. 2. This copper coating may be deposited on the surface
of the iron by any of the usual processes, but it is preferable to coat
it with a thin sheet of compactly rolled copper secured by solder. The
object may also be attained by coating the surface with molten tin
or other suitable metal. The object of making the under surface of

page_text: the plug F concave, as represented, is that the mercury within the
cup when expanded by heat so as to rise therein always assumes a
rounded or spherical form on its surface, the centre being more elevated
than at the sides or around the edges, and therefore if the top of the
cup or bottom of the plug F were made with a plane or straight face
it would follow that when the mercury rose in the cup, it being highest
at the centre, would enter and close the lower end of the tube E, while
air would remain confined in the interior angle or corner of the cup,
but by making the top of the cup of the spherical form on its interior,
as represented in Fig. 2, this difficulty is entirely obviated. Every
gauge must be graduated by attaching it to a boiler alongside of a
standard mercurial gauge, and commencing with the steam at the
lowest point raise it to the highest pressure desired, and marking the
graduations with care on the plate D at the proper points to represent the
different degrees of pressure as the same are indicated by the standard
mercurial gauge during the operation. Each gauge is graduated in
this way by direct pressure test instead of by thermometric marks
converted by a table. The gauge is to be connected to the boiler by
means of a flange H, as represented in Fig. 1, or by a tube, and steam
is admitted to the steam chamber I surrounding the mercury reservoir B
through the opening I' if attached to the side of the boiler, or through
the tube L if set above the boiler or engine, the proper quantity of
mercury of course having been first placed within the cup B; as the
pressure increases the heat expands the mercury in the cup B, and
will cause it to ascend the tube E, where the graduations and numbers
will at once indicate the pressure of the steam. A small orifice c¹ is
made in the case A to permit the escape of cold air as steam is let
into it after having become cool by nonuse, and also to permit the
constant escape of steam in small quantities to counteract any con-
densation that might occur, and which would thus tend to reduce the
temperature of the steam in the chamber I below that in the boiler. If
desired this orifice may be provided with a cock, by which it can be
closed or opened at pleasure. A drip pipe P with a cock is attached
at the bottom of the case to permit the escape
of any
water that may
be formed by condensation therein. If desired there may be a pipe
connected with the drip pipe to convey the water back into the water
space of the boiler. To prevent loss of heat by radiation the caso A
with the steam pipe leading to it (if one be used) should be packed
with any
suitable non-conducting material.

page_text: Having thus described the Invention which has been communicated
to me, I claim as the Invention secured to me by Letters Patent,―
First. The combination of the metallic mercury reservoir B and the
exterior steam chamber I, the glass tube E, and a prossure gauge scale
attached thereto, determined by the expansion of the mercury by the
heat of the steam conducted from the boiler to the steam chamber I.
Second. The combination of the metallic mercury reservoir B, the
exterior stcam chamber I, the graduated glass tube E, placed entirely
outside of a boiler, having a steam connection therewith by a tube
or flange.
Third. The drip tube attached to the steam chamber I.
Fourth. I claim coating with copper or other suitable material the
surface of the mercury cup, for the purpose set forth.
Fifth. The flexible bag n secured to the end of the tube E, for the
purpose set forth.
Sixth. The process of graduating the gauge by applying steam to
the steam chamber at a scries of pressures determined by a standard
gauge, and marking the position of the mercury corresponding thereto.
In witness whereof, I, the said William Edward Newton, have
hereunto set my hand and seal, the Fifth day of August,
in the year of our Lord One thousand eight hundred and
sixty-eight.
Witness,
J. W. MOFFATT,
66, Chancery Lanc.
W. E. NEWTON. (L.s.)