IMPROVEMENTS IN PRESSURE AND VACUUM GAUGES
Year: 1864

page_text: LETTERS PATENT to Henry Brockhurst, of Beech House, Little Hampton,
in the County of Sussex, and John Sullivan, of No. 177, Great Dover
Street, in the County of Surrey, for the Invention of "IMPROVEMENTS IN
PRESSURE AND VACUUM GAUGES."
Sealed the 22nd March 1864, and dated the 21st January 1864.
PROVISIONAL SPECIFICATION left by the said Henry Brockhurst and John
Sullivan at the Office of the Commissioners of Patents, with their Petition,
on the 21st January 1864.
We, HENRY BROCKHURST, of Beech House, Little Hampton, in the County
of Sussex, and JOHN SULLIVAN, of No. 177, Great Dover Street, in the
County of Surrey, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PRESSURE AND VACUUM GAUGES," to be as follows:-
Our improvements have reference to that description of pressure and
vacuum gauges known as Bourdon's gauges, for which Letters Patent were
granted to Charles Cowper, bearing date the 15th day of December 1849
(No. 12,889).
One of our improvements consists in making the curved tube in the interior
of which the pressure of the steam is exerted, or which communicates with
the vacuum of a semicircular or other suitable form, and so arranging the
same that the one end of the tube being fixed to the shoe at the bottom of the
casing, no part of the upper free end of the same shall extend beyond or be
curved in a downward direction beyond the vertical centre line passing through
the inlet pipe. To this free end of the tube we attach an arm or connecting

page_text: picce of such a length as to supply the place of that portion of the tube which
in the present mode of construction is curved down beyond the centre vertical
line, and the extremity of this arm we connect by means of the usual link to
the toothed sector that communicates the motion of the tube to the index.
By this arrangement all accumulation of water in the tube is prevented, and
the motion is rendered more steady, in addition to which the cost of con-
struction is lessened, whilst the advantage of the existing form for communi-
cating the motion to the index is retained.
Another part of our Invention has for its object to prevent the accumulation
of water in the forms of tube at present in use, and the consequent deterioration
of the same through the freezing of such water.
the freezing of such water. For this purpose we fill the
tube either partially or entirely with cotton wick or other similar material
soaked in oil, or with oil only.
Another part of our Invention has for its object to facilitate the attaching
and detaching of the movement from the casing. For this purpose instead of
attaching the same to the casing itself, we attach it to a separate plate that is
fixed to the shoe of the tube.
gauge is
Another part of our Invention has for its object to prevent the overstraining
and consequent deterioration and putting out of shape of the curved tube that
now frequently occurs through the admission of steam into the gauge at a
greater pressure than it is constructed to bear. For this purpose we either
provide the tube with a small valve or self-acting stop-cock, so constructed
that when the pressure of the steam exceeds the pressure which the
calculated to bear, such valve or stop-cock will close and shut off the com-
munication between the gauge and the steam boiler. Or we fix stops to the
casing in positions corresponding with the extreme range of motion of the
tube when subjected to the greatest pressure which it is calculated to bear, so
that when the tube comes in contact with such stops it cannot be further
extended by any extra pressure to which it may be subjeeted.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Brockhurst and John Sullivan in the Great Seal
Patent Office on the 20th July 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, HENRY
BROCKHURST, of Beech House, Little Hampton, in the County of Sussex, and
JOHN SULLIVAN, of No. 177, Great Dover Street, in the County of Surrey,
send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Iler Letters
Patent, bearing date the Twenty-first day of January, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-seventh year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
us, the said Henry Brockhurst and John Sullivan, Her special licence that we,
the said Henry Brockhurst and John Sullivan, our executors, administrators,
and assigns, or such others as we, the said Ilenry Brockhurst and John Sullivan,
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 Invention for "IMPROVEMENTS IN PRESSURE AND
VACUUM GAUGES," upon the condition (amongst others) that we, the said Henry
Brockhurst and John Sullivan, our executors or administrators, by an instru-
ment in writing under our or their hands and seals, or under the hand and
seal of one of us, or them, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be per-
formed, 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 Henry Brockhurst and John Sullivan,
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.
Drawing, and to the figures and letters marked thereon, that is to say :-
Our improvements have reference to that description of pressure and
vacuum gauges known as Bourdon's gauges, for which Letters Patent were
granted to Charles Cowper, bearing date the 15th day of December 1849
(No. 12,889).
One of our improvements consists in making the curved tube, in the
interior of which the pressure of the steam is exerted, or which communicates.
with the vacuum of a semicircular or other suitable form, and so arranging
the same that the one end of the tube being fixed to the shoe at the bottom
of the casing no part of the upper free end of the same shall extend beyond.
or be curved in a downward direction beyond the vertical centre line passing
through the inlet pipe. To this free end of the tube we attach an arm or.
connecting piece of such a length as to supply the place of that portion of the
tube which in the present mode of construction is curved down beyond.the.
centre. vertical line, and the extremity of this arm or connecting picco we:

page_text: connect to a toothed sector or crank that communicates the motion of the tube
to the index. By this arrangement all accumulation of water in the tube is
prevented, and the motion is rendered more steady, in addition to which the
cost of construction is lessened, whilst the advantage of the existing form for
communicating the motion to the index is retained.
Another part of our Invention has for its object to prevent the accumulation
of water in the forms of tube at present in use, and the consequent deterioration
of the same through the freezing of such water. For this purpose we fill the
tube either partially or entirely with cotton wick, or other similar material
soaked in oil, or with oil only.
Another part of our Invention bas. for its object to facilitate the attaching
and detaching of the movement to and from the casing. For this purpose
instead of attaching the same to the casing itself we attach it to a separate
plate that is fixed to the shoe of the tube.
Another part of our Invention has for its object to prevent the overstraining
and consequent deterioration and putting out of shape of the curved tube that
now frequently occurs through the admission of steam into the gauge at a
greater pressure than it is constructed to bear. For this purpose we either
provide the tube with a small valve or self-acting stop-cock, so constructed
that when the pressure of the steam exceeds the pressure which the gauge
is calculated to bear, such valve or stop-cock will close and shut off the
communication between the gauge and the steam boiler; or we fix stops to
the casing in positions corresponding with the extreme range of motion of the
tube when subjected to the greatest pressure which it is calculated to bear,
so that when the tube comes in contact with such stops it cannot be further
extended by any extra pressure to which it may be subjected.
Figure 1 on the accompanying Drawing shows a Bourdon's gauge (with
the dial plate removed), having several of our before described improvements.
A is the curved tube which is attached at bottom to the shoe B, and terminates
at the top at the centre line of the gauge, the curvature of the whole of the
tube being in a downward direction, so that no water can accumulate in the
tube. To the free end of the tube is attached the arm or connecting piece C,
which in this case is fixed to the same, and is formed with a curvature
corresponding to that of the tube. This arm communicates the motion of the
tube to the index G, shown in dotted lines, by means of the link D, toothed
sector E, and pinion F. The pivots e and f upon which the sector and
pinion work, instead of being carried by the casing of the gauge as heretofore,
are carried by a separate plate H fixed to the shoe B; I, I, I, are stops fixed
to the casing in positions corresponding with the extreme motion of the

page_text: tube A when subjected to the highest pressure that it is intended to
indicate, so that the tube on coming against these stops cannot be distended
any farther by any pressure to which it may be subjected above such
maximum, and it is consequently protected from being injured thereby.
Figure 2 shows another arrangement of our improved gauge, in which the
connecting piece or link C attached to the free end of the tube A, com-
municates the motion of the tube to the index G, simply by means of the
crank J fixed to the same axis f that carries the index G, shown in dotted
lines, and which in this arrangement is fixed excentrically in the casing;.
H is the separate plate carrying the axis f, which plate is attached to the.
shoe B. To this latter is fixed a second bent tube K, also communicating
with the boiler, the upper free end of which is connected by means of the
link L to the lever or handle M of a stop-cock N, situated in the passage
communicating with the indicating tube A. The strength of the tube K is
so proportioned that when the pressure of the steam in the boiler exceeds that
which the tube A is required to indicate, the free end of the tube K is raised
to such an extent as to close the stop-cock N, and thereby to shut off the
communication between the boiler and the tube A. In order to ascertain
what pressure exists in the boiler after the tube A is closed, an index O may
be fixed to the plug of the stop-cock N, which, as the plug is turned round by
the further distension of the tube K, would indicate upon a scale the degree.
of pressure existing in the boiler above and beyond that which the tube A is
intended to indicate.
Instead of the regulating tube and cock just described, the arrangement
shown in part section at Figure 3 may be employed. Here the passage b in
the shoe B leading to the tube A is formed with a conical seating for the
conical valve N, which, when the pressure of the steam does not exceed the
pressure that the tube A is intended to indicate, is kept open by the spring K
pressing down the stalk n of the same. The pressure of the spring K is
regulated so as to correspond with the maximum pressure of the gauge by
means the nuts a, a, screwed on to the stalk n, so that when such maximum
pressure of the steam is exceeded, the valve N is closed and the communication
between the boiler and the tube A is cut off.
Having now described the nature of our Invention, and the best means we
are acquainted with of performing the same, we wish it to be understood that
we do not limit the application of our improvements to the forms of pressure
gauges shewn on the accompanying Drawing, as they may be applied with
equal advantage to any other known forms of the Bourdon's gauge; but what
we claim is,

page_text: First, forming those tubes that are attached by one end to the shoe in such
à manner that the whole of their curvature has an ascending direction, or
does not exceed a semicircle, and substituting for that portion of the tube,
which in the present arrangement descends towards and is connected to the
movement, an arm or connecting piece or link attached to the free end of
the tube, and serving to communicate the motion of the tube to the index by
means of a toothed sector or crank.
Second, filling the tubes wholly or partially with cotton wick or other
similar suitable material soaked in oil, or with oil only, in order to prevent the
accumulation of water in the tube, and the consequent deterioration of the
same by the freezing of such water.
Third, attaching the index and movement of the gauge to a separate plate
fixed to the shoe..
Fourth, fixing to the casing of the gauge pins or studs in such positions
that when the tube is subjected to the greatest pressure that it is intended to
indicate it will come against such pins or studs, and will thereby be prevented
from being further distended by any increase of pressure.
Fifth, providing in the passage through which the tube communicates
with the boiler a self-acting stop-cock or valve that is closed when the pressure
of the steam exceeds the maximum pressure that the gauge is intended to
indicate.
In witness whereof, we, the said Henry Brockhurst and John Sullivan,
have hereunto set our hands and seals, this Twentieth day of July,
in the year of our Lord One thousand eight hundred and sixty-four.
HENRY BROCKUID ST
HENRY BROCKHURST
(5.5.)
JOHN SULLIVAN.
(L.S.)