IMPROVEMENTS IN GAS REGULATORS FOR REGULATING THE SUPPLY OF GAS TO THE BURNER,
Year: 1854

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
HULETT, of High Holborn, London, send greeting.
WHEREAS, by Letters Patent under the Great Seal of the United
Kingdom of Great Britain and Ireland, bearing date at Westminster, the
Fourth day of January, in the seventeenth year of the reign of Her present
most Excellent Majesty Queen Victoria, Her said Majesty did grant unto me,
the said David Hulett, my executors, administrators, and assigns, the sole use,
benefit, and advantage of an Invention of "IMPROVEMENTS IN GAS REGULATORS
FOR REGULATING THE SUPPLY OF GAS TO THE BURNER," partly a communication, to
have, hold, exercise, and enjoy the same, unto and by me, my executors,
administrators, and assigns, within the United Kingdom of Great Britain
and Ireland, and the Islands of Jersey, Guernsey, Alderney, Sark, and Man,
for the term of fourteen years: And whereas I, the said David Hulett, in
pursuance of a proviso in the said Letters Patent contained, did, by an instru-
ment in writing under my hand and seal (commonly called a Specification),
describe and ascertain the nature of the said Invention, and in what manner the
same is to be performed, and did cause the same instrument to be filed in the
Great Seal Patent Office on the Fourth day of July, in the year of our Lord
One thousand eight hundred and fifty-six: And whereas since I caused my said
Specification to be filed I have found that the modifications of my apparatus
therein described, which are shewn in Figures 16 and 17 of the Drawings.
accompanying the said Specification, are not of much value or utility, and I am
therefore desirous of disclaiming so much of my said Specification as relates to

page_text: those modifications: And whereas since I caused my said Specification to be
filed I have also been advised that it is doubtful whether my said Specification
may not be construed as claiming not only the whole apparatus therein
described, but also all the several parts thereof, some of which parts may not
be new, and I am therefore desirous of disclaiming such parts in manner
herein-after expressed.
NOW KNOW YE, therefore, by and with the leave of Sir Richard Bethell,
Knight, Her Majesty's Attorney General, and for the reasons aforesaid, and as
to so much of the said Specification as consists of the words, letters, and
figures following:"A modification of the foregoing is represented in vertical
section by Fig. 16; it consists of a cylindrical box or case A, A; B is the
"inlet; C, the outlet passages. Into the bottom of the vessel is screwed the
piece of brass D or other metal, the inside of which is grooved out, as
shewn at D'. The valve E is hollow, and slides over the piece of metal D.
"Three or four steadying pins project from the inside of the valve to keep it
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equidistant from the metal D. The valve is attached to a rod F, to which
the cylinder G is secured, as in the arrangement before described, Figs. 1
"to 15. The lever H and other working parts being above the cylinder, are
"not within the influence of the gas. The pressure of the lever on the
cylinder is adjusted in the same manner as before described. When the
cylinder is lifted, the valve is drawn upward, and the angular edge of the
aperture I' in the partition I dips into the groove formed round the top of
"the valve by the edge E rising a short distance above the curved top; the
groove is filled with mercury to make a gas-tight joint when the edge of the
partition I dips into it. One or more apertures are made in the upper part
" of the valve to maintain an equality of pressure on both sides of the valve.
The direction of the gas as it passes through the regulator is indicated by
arrows. Fig. 17 is a vertical section of another arrangement of regulator.
K is the inlet; L, the outlet passages; M, a grooved piece of metal con-
taining mercury; N, the valve connected to the rod N¹; O, the lever;
P, the lever supports. When the valve is lifted by a variation of the
pressure, the curved edge of the metal Q dips into the mercury, thus
stopping the passage of the gas. The action of the other parts of the
apparatus is similar to the foregoing." I, the said David Hulett, do here-
by disclaim all, so much, and such parts of the said Specification as herein-
before set forth; and by and with the leave aforesaid, and for the reasons
aforesaid, I, the said David Hulett, do hereby disclaim all parts of the com-
bination forming the apparatus described in the undisclaimed parts of the said
Specification as being of my said Invention, save and except the gas-tight valve
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page_text: made by causing the valve to dip into mercury, as mentioned in the Speci-
fication, the joints of the valve rod and of the rod m placed within a recess
below the surface of mercury, as mentioned in the Specification. The tube g¹
and channels connected therewith for introducing mercury into the interior of
the apparatus, as mentioned in the Specification, and the regulating lever
or bar and weight mentioned in the Specification, when the same are
respectively used and applied in the manner described in the Specification.
And in order to cause the nature and effect of the above Disclaimer to be
more clearly understood, I do hereby, with the leave aforesaid, alter the said
Specification, so that the same, with the aid of the Drawings thereunto
annexed, shall describe the Invention as follows:-
The object of this Invention is to regulate the supply of gas as it issues from
the main to the burner, in order to prevent fluctuation in the height of the
flame notwithstanding any difference that may occur in the pressure of the gas
in the main. It is this inequality of pressure that obliges the consumer to
continually regulate the height of the flame of the burners he has in use; and
in large establishments this is attended with much inconvenience, waste, and
danger. By the self-acting mechanical arrangements herein-after described
the flow of gas to the burner may be regulated with the utmost nicety, and a
steady uniform light maintained for any length of time.
My improved regulator consists of a cast-iron vessel, with inlet and outlet
passages for the admission and emission of the gas; the inlet is covered by a
valve, the edge of which dips into a groove containing mercury; this renders
the joint perfectly gas-tight without impeding the motion of the valve, which
is hung in such manner as to move with the slightest variation of pressure.
The valve is attached by a rod to a short cylinder, the lower part of which is
open and dips into a channel or groove containing mercury. The cylinder
covers and surrounds the inlet passage; thus, as the gas flows from the main
through the inlet of the regulator, it exerts an upward pressure on the cylinder,
which is adjusted by means herein-after described to admit the requisite
quantity of gas for the supply of the burners. If the pressure of gas issuing
from the main be increased, it lifts the cylinder which closes the valve, but
the consumption by the burners quickly reduces the pressure within the
regulator; this causes the cylinder to fall and open the inlet passage. The
particular construction and arrangement of the apparatus will be more readily
understood by reference to the accompanying Drawings, and to the letters and
figures marked thereon.
Fig. 1, Sheet A, is a vertical section of the regulator with the cover cylinder
and valve removed; Fig. 2 is a plan of the same. a is a cast-iron cylindrical

page_text: vessel or box; b is the inlet; c, the outlet passages. The passage b is closed
by a valve. d is a recess cast in the lower part of the box a; this forms a
small cistern or reservoir, which is filled with mercury when the regulator is
adjusted for use. The circular space e is to receive the valve seat, which is
secured to the box a by screws passing through the holes e¹. f is a channel
for groove containing mercury; this communicates with the channel 9, which
conveys the mercury into the cistern or recess d.
The mercury or other suitable fluid is poured into the regulator through the
tube g', by which it is conveyed to the recess d and channels f. 9. Fig. 3 is a
plan of the valve; Fig. 4, a view of the lower side; and Fig. 5, a vertical
section of the same, drawn to a larger scale than Figs. 1, 2. h is the valve
seat, which is secured by screws to the box a; i is the valve, the rod k of
which is jointed at 7 to the seat h; to the outer end of the rod k is jointed a
small rod or spindle, which supports the cylinder. A groove or channel n is
formed in the valve seat h, which surrounds the valve; when this is filled with
mercury or other suitable fluid, the valve dips into it and forms a gas-tight
joint. When the valve is secured to the box a, the joint of the valve rod is
within the recess d and below the surface of the mercury, as also is the joint
of the rod m, as shown by Fig. 5. This arrangement prevents the clogging
of the joints arising from depositing of oily and bituminous matters. Figs. 6, 7,
represent a section and plan of the cylinder. m is the rod or spindle, secured
at one end to the valve rod k; at the upper part is a nut o, upon which the
cylinder p rests. The cylinder is made of iron or other suitable metal or
material, and open at the bottom, as shown by Fig. 6. It is secured to the
rod m by a nut q, which is screwed down upon the cylinder; discs or washers
of leather are placed between the nuts to render the joint gas-tight.
At the top of the rod m is an eye, to which is fastened a metal bar r, shown
by plan in Fig. 8. Fig. 9 is a side view; and Fig. 10, a view of the under
side of the same. It is secured to the rod m by a pin passing through the
lugs s. The bar is supported by a rod t, which passes through the lug u.
The ends of the rod t are supported by the pins or brackets v, screwed in the
edges of the box a. The bar r is perforated with holes, as shewn in the
Drawing; in one of these a small weight w, shown in plan and section by
Figs. 11, 12, is placed. Fig. 13, Sheet B, is a section of the regulator
arranged for use; Fig. 14, a plan; and Fig. 15, an external view of the
same. The pressure of the bar r on the cylinder p is regulated by the position
of the weight w; if it be placed at the back of the fulcrum u, or to the left-
hand side of Fig. 13, the pressure may be wholly taken off the cylinder p, and
it will be gradually increased as the weight is moved along the bar. When

page_text: the regulator is to be adjusted for use, after attaching it to the inlet and outlet
pipes, the channel p, the recess d, and the grooves f, g, are to be filled with
mercury by pouring it into the pipe or tube g¹ until the metal is nearly level
with the top; the nut g" is then screwed in the pipe, the gas turned on, and
the weight w put in a position so as to nearly balance the cylinder p when the
gas is pressing it upward. Any increase of pressure from the main will lift
the cylinder p, which causes the valve i to descend and shut, or partially so;
the inlet until the pressure becomes uniform. On the contrary, should the
pressure from the main decrease, the cylinder will descend and open the inlet
passage to a greater extent.
The regulator being properly adjusted, as before described, the cover'x,
Fig. 15, is put on to secure the internal parts from injury; the apparatus will
then require no further attention.
A modification of the foregoing is represented in vertical section by Fig. 16-1-it
consists of a cylindrical box or ease A, A, B is the inlet ; C, the outlet-passages.
Into the bottom of the vessel is sorewed the piece of brass D-or-other-metal, the
inside of which is grooved out, as shown at D'. The valve E is hollow, and slides
over the piece of metal D. Three or four steadying pins project from the inside
of the valve, to keep it equidistant from-the-metal D. The valve is attached to a
rod F, to which the cylinder G is secured, as in the arrangement before-described,
Figs. 1 to 15. The lever II and other working parts being above the cylinder are
not within the influence of the gas. The pressure of the lever on the cylinder is
adjusted in the-same manner as before described. When the cylinder is lifted, the
valve is drawn upward, and the angular edge of the aperture I' in the partition I
dips into the groove-formed round the top of the valve by the edge E', rising e
short distance above the curved top. The grove is filled with mereury to make a
gas tight joint when the edge of the partition I-dips into it. One or more-apertures
are-made-in-the-upper part of the valve to maintain an equality of pressure on both
cides of the valve. The direction of the gas as it passes through the regulator-is
indicated by arrows. Fig. 17 is a vertical section of another arrangement of
regulator. K is the inlet-; L, the outlet passages; M, a grooved pleee of metal
containing mereury; N; the valve connected to the red N¹-;-O, the lever-;-P, the
lever-supports. When the valve is lifted by a variation of the pressure, the curved
edge of the metal Q dips into the mereury, thus stopping the passage of the gas.
The eetien of the other parts of the apparatus is similar to the foregoing. In all
cases the regulators are to be provided with covers, as shown in the Figures.
The material I prefer to use for the manufacture of the valves is malleable
iron, which I afterwards coat with tin, in order that the mercury surrounding
the valve may adhere to it when it descends, and make a joint gas-tight.

page_text: Having described the nature of my Invention, and the manner of carrying
the same into effect, I wish it to be understood that I do not confine myself to
claim the different parts or precise arrangement of the different parts as shown
in the accompanying Drawing and or described herein, save and except the
gas-tight valve made by causing the valve i to dip into mercury, as above
mentioned, the joints of the valve rod and of the rod m¹ placed within a
recess below the surface of mercury, as above mentioned, the tube g¹ and
channels connected therewith for introducing mercury into the interior of the
apparatus, as above mentioned, and the regulating lever or bar and weight
above mentioned, when the same are respectively used in the manner herein-
before described, so long as the distinctive-and-peculiar features of my Inven
tion be retained; but what I do claim and desire to secure by these Letters
Patent is, the construction of the apparatus for regulating the flow of gas,
substantially as herein described and shown.
In witness whereof, I, the said David Hulett, have hereunto set my
hand and seal, the 4th day of July, in the year of our Lord One thou-
sand eight hundred and fifty-four.
D. HULETT. (L.S.)
k
To the Commissioners of Patents for Inventions.
I hereby grant my fiat giving leave to the above-named David Hulett to
file in the Great Seal Patent Office, with the Specification to which the same
relates, the above-written Disclaimer and Memorandum of Alteration.
RICHARD BETHELL.

page_text: LETTERS PATENT to David Hulett, of High Holborn, for the Invention of
IMPROVEMENTS IN GAS REGULATORS FOR REGULATING THE SUPPLY OF GAS TO
THE BURNER."-Partly a communication.
PROVISIONAL SPECIFICATION left by the said David Hulett at the Office
of the Commissioners of Patents, with his Petition, on the 4th January
1854.
I, DAVID HULETT, of High Holborn, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN GAS REGULATORS FOR REGULATING THE
SUPPLY OF GAS TO THE BURNER" to be as follows:-
My Invention consists of improvements in apparatus for regulating the
supply of gas to the burner, so that any number of lights may be kept at an
uniform height and not be affected by the varying pressure of the gas as it
issues from the main. Fig. 1, on the accompanying Drawings, represents a
plan of an improved regulator. a is a cast iron cylindrical vessel with inlet
and outlet passages, b, c; the former is shown by a dotted line, the passage
being covered by the valve d. A recess or well e is made in the bottom of
the cylinder a, to receive the valve rod which is bent downwards at right
angles to the valve and again in a direction parallel with the bottom of the
recess. By this arrangement the joints are below the lower part of the cylinder,
and when the recess or well is filled with mercury, oil, or other suitable fluid,
the gas cannot affect the pins or clog the joints. The valve seat is also made

page_text: with a groove f, round it to receive a small quantity of oil or mercury to make
the valve when closed gas tight. To the end of the valve rod is fastened a
vertical spindle which is secured to a disc or short cylinder g, made somewhat
smaller than the outer one a. The upper end of the spindle is fastened to a
piece of brass h, which extends across the disc; at right angles to the brass
lever h, is a metal rod i, to which the lever his secured so as to poise the
disc g, when a metal weight is placed on the lever. On the inside of the
cylinder a, is a groove in which the disc g rests. In this groove is placed some
mercury, so as to form a liquid gas tight joint, and allow the disc to rise or
fall as required. The lever h, is perforated with holes, in one of which is
placed a small weight to partly balance the disc, that is to say, if the disc be
nearly in equilibrium, a very slight pressure of gas will close the valve, or it
may be placed so as to require a strong upward pressure before the valve be
affected. Thus the gas flows through the inlet passage b, lifting the valve d,
filling the chamber formed by the disc g, and passes to the burners by the
outlet passage c.
When the pressure of gas is greater than the amount
required for the burners, it lifts the disc g, which being secured by the spindle
to the valve rod, it closes, or partially so, the inlet passage, thus reducing the
quantity of gas flowing in by the passage b. Fig. 2 is a plan of a counter-
balance valve in which the joints are protected by a covering of mercury or other
suitable fluid; k is a recess made in the plate forming the valve seats; the
valve rod or spindle is bent downwards and secured by a pin at the bottom of
the recess k; the outer end is also bent in a similar inanner, so that both joints
may be covered with mercury. In some cases I should attach the disc g,
Fig. 1, to the valve by a joint at the back of the inlet passage, and have the
valve hung below the inlet; the extra pressure of the gas would lift the disc
and draw the valve up to its seat, and thus partially close the passage when
the pressure became too great. In this arrangement also the joints and
working parts would be protected by mercury. Figs. 3 and 4 represent
vertical sections of improved gas regulators, differing in arrangement from the
foregoing; 1, 1, is a cylindrical vessel, with inlet and outlet passages m, n; into
the lower part of the vessel l, is screwed the piece of metal o, having a recess
or groove on the inner side, in which is placed some mercury or other suitable
fluid. The valve p is hollow, and of the form shown in the Drawing; a groove
p is made on the upper part and filled with mercury, in which the bevilled
edge of the aperture p dips when the valve is raised, which prevents the
valve from sticking as would otherwise occur by the tar depositing thereen, at
the same time it forms a gas-tight joint. The valve spindle is connected to a
disc q, working in mercury as herein-before described. The arrows indicate

page_text: the passage of the gas, and it will be observed that the joints of the adjusting
lever are above the disc where the gas cannot have access. The lower part of
the valve has three or four pins projecting from the inside to keep it equi-
distant from the metal o, and the upper part is perforated with holes to
maintain a nearly uniform pressure upon both sides of the valve.
Fig. 4 is a modification of Fig. 3, and marked with similar letters of
reference; in this arrangement the chamber connected with the outlet is
dispensed with. In the foregoing, I have described the principle of my
Invention of improved apparatus for regulating the flow of gas, but I reserve
the right to vary the details thereof.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said David Hulett in the Great Seal Patent Office on the 4th
July 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
HULETT, of High Holborn, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourth day of January, in the year of our Lord One
thousand eight hundred and fifty-four, in the seventeenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
David Hulett, Her special licence that I, the said David Hulett, my execu-
tors, administrators, and assigns, or such others as I, the said David Hulett,
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 GAS REGULATORS FOR BEGULATING
THE SUPPLY OF GAS TO THE BURNER," (partly a communication) upon the con-
dition (amongst others) that I, the said David Hulett, by an instrument in
writing under my hand and seal, 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 I, the said David Hulett, 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

page_text: statement, reference being had to the Drawings hereunto annexed, that is
to say:-
The object of this Invention is to regulate the supply of gas as it issues
from the main to the burner, in order to prevent fluctuation in the height of
the flame, notwithstanding any difference that may occur in the pressure
of the gas in the main. It is this inequality of pressure that obliges the
consumer to continually regulate the height of the flame of the burners he has
in use, and in large establishments this is attended with much inconvenience,
waste, and danger. By the self-acting mechanical arrangements herein-after
described, the flow of gas to the burner may be regulated with the utmost
nicety, and a steady uniform light maintained for any length of time.
My improved regulator consists of a cast iron vessel with inlet and outlet
passages for the admission and emission of the gas; the inlet is covered by a
valve, the edge of which dips into a groove, containing mercury; this renders
the joint perfectly gas-tight without impeding the motion of the valve which is
hung in such manner as to move with the slightest variation of pressure.
The valve is attached by a rod to a short cylinder, the lower part of which is
open and dips into a channel or groove containing mercury; the cylinder
covers and surrounds the inlet passage; thus, as the gas flows from the main
through the inlet of the regulator it exerts an upward pressure on the cylinder,
which is adjusted by means herein-after described to admit the requisite
quantity of gas for the supply of the burners. If the pressure of gas issuing
from the main be increased, it lifts the cylinder which closes the valve, but
the consumption by the burners quickly reduces the pressure within the
regular; this causes the cylinder to fall and open the inlet passage. The
particular construction and arrangement of the apparatus will be more readily
understood by reference to the accompanying Drawings and to the letters and
figures marked thereon.
passage
b
Fig. 1, Sheet A, is a vertical section of the regulator, with the cover,
cylinder, and valve removed; Fig. 2, is a plan of the same. a is a cast iron
cylindrical vessel or box; b is the inlet; c, the outlet
passages. The
is closed by a valve; d is a recess cast in the lower part of the box a; this
forms a small cistern or reservoir which is filled with mercury when the
regulator is adjusted for use. The circular space e is to receive the valve
seat, which is secured to the box a, by screws passing through the holes e';
f is a channel or groove for containing mercury; this communicates with the
channel 9. which conveys the mercury into the cistern or recess d.
The mercury or other suitable fluid is poured into the regulator through the
tube g, by which it is conveyed to the recess and channels f, g. Fig. 3 is

page_text: a plan of the valve; Fig. 4, a view of the lower side; and Fig. 5, a vertical
section of the same, drawn to a larger scale than Figs. 1, 2. h is the valve
seat, which is secured by screws to the box a; i is the valve, the rod k of
which is jointed at 7 to the seat ; to the outer end of the rod k is jointed-a
small rod or spindle which supports the cylinder. A groove or channel n is
formed in the valve scat h, which surrounds the valve; when this is filled with
mercury or other suitable fluid, the valve dips into it and forms a gas-tight
joint. When the valve is secured to the box a, the joint of the valve rod is
within the recess d, and below the surface of the mercury, as also is the joint
of the rod m, as shown by Fig. 5. This arrangement prevents the clogging of
the joints arising from depositing of oily and bituminous matters. Figs. 6, 7,
represent a section and plan of the cylinder; m is the rod or spindle secured
at one end to the valve rod k; at the upper part is a nut o, upon which the
cylinder prests. The cylinder is made of iron, or other suitable metal or
material, and open at the bottom as shown by Fig. 6. It is secured to the
rod m by a nut q, which is screwed down upon the cylinder; discs or washers
of leather are placed between the nuts to render the joint gas-tight.
At the top of the rod m is an eye, to which is fastened a metal bar 2, shown
in plan by Fig. 8; Fig. 9 is a side view; and Fig. 10, a view of the under
side of the same. It is secured to the rod m, by a pin passing through the
Jugs s; the bar is supported by a rod t, which passes through the lug u; the
ends of the rod t are supported by the pins or brackets v, screwed in the edges
of the box a. The bar is perforated with holes, as shown in the Drawing;
in one of these a small weight w, shown in plan and section by Figs. 11, 12,
is placed. Figs. 13, Sheet B, is a section of the regulator arranged for use;
Fig. 14, a plan, and Fig. 15, an external view of the same. The pressure
of the bar r, on the cylinder p, is regulated by the position of the weight w.
If it be placed at the back of the fulcrum u, or to the left hand side of
Fig. 13, the pressure may be wholly taken off the cylinder p, and it will
be gradually increased as the weight is moved along the bar.
regulator is to be adjusted for use, after attaching it to the inlet and outlet
pipes, the channel p, the recess d, and the grooves f, g, are to be filled with
mercury by pouring it into the pipe or tube g', until the metal is nearly level
with the top; the nut g" is then screwed in the pipe, the gas turned on, and
the weight w put in a position so as to nearly balance the cylinder p, when the
gas is pressing it upward. Any increase of pressure from the main will lift
the cylinder p, which causes the valve i to descend, and shut, or partially so,
the inlet, until the pressure becomes uniform. On the contrary, should the
When the

page_text: pressure from the main decrease, the cylinder will descend and open the inlet
passage to a greater extent.
The regulator being properly adjusted as before described, the cover a,
Fig. 15, is put on to secure the internal parts from injury; the apparatus will
then require no further attention.
A modification of the foregoing is represented in vertical section by Fig. 16. It
consists of a cylindrical box or case A, A. B is the inlet, C, the outlet passages.
Into the bottom of the vessel is screwed the piece of brass D, or other metal,
the inside of which is grooved out as shown at D'. The valve E is hollow and
slides over the piece of metal D; three or four steadying pins project from the
inside of the valve to keep it equidistant from the metal D. The valve is
attached to a rod F, to which the cylinder G is secured as in the arrangement
before described, Figs. 1 to 15. The lever H, and other working parts, being
above the cylinder, are not within the influence of the gas. The pressure of
the lever on the cylinder is adjusted in the same manner as before described;
when the cylinder is lifted the valve is drawn upward, and the angular edge of
the aperture I', in the partition I, dips into the groove formed round the top
of the valve by the edge E¹, rising a short distance above the curved top; the
groove is filled with mercury to make a gas-tight joint when the edge of
the partition I, dips into it. One or more apertures are made in the upper
part of the valve to maintain an equality of pressure on both sides of the
valve. The direction of the gas as it passes through the regulator is indicated
by arrows. Fig. 17 is a vertical section of another arrangement of regulator;
K, is the inlet, L, the outlet passages; M, a grooved piece of metal, contain-
ing mercury; N, the valve connected to the rod N¹; O, the lever; P, the
lever supports. When the valve is lifted by a variation of the pressure, the
curved edge of the metal Q, dips into the mercury, thus stopping the passage
of the gas; the action of the other parts of the apparatus is similar to the
foregoing. In all cases the regulators are to be provided with covers, as
shown in the Figures. The material I prefer to use for the manufacture of
the valves is malleable iron, which I afterwards coat with tin, in order that the
mercury surrounding the valve may adhere to it when it descends and makes
the joint gas-tight.
Having described the nature of my Invention and the manner of carrying
the same into effect, I wish it to be understood that I do not confine myself to
the precise arrangement of the different parts, as shown in the accompanying
Drawing and described herein, so long as the distinctive and peculiar features
of my Invention be retained; but what I claim, and desire to secure by these

page_text: Letters Patent, is, the construction of the apparatus for regulating the flow of
gas, substantially as herein described and shown.
In witness whereof, I, the said David Hulett, have hereunto set my hand
and seal, the 4th day of July, in the year of our Lord One thousand
eight hundred and fifty-four.
D. HULETT. (L.S.)