IMPROVEMENTS IN GAS METERS
Year: 1875

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
“IMPROVEMENTS IN GAS METERS."—A communication from abroad by
Edouard Armand Robert d'Hurcourt, of Paris, France.
Sealed the 21st August 1875, and dated the 2nd March 1875.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 2nd March 1875.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN GAS METERS," to be as
follows:-
:―
This Invention relates to improvements in gas meters, and consists
mainly in the employment of pairs of measuring chambers or gas-
holders dipping in water, and mounted to oscillate on an axis so as to be
filled and emptied alternately with gas.

page_text: In order that the Invention may be more readily understood I have
illustrated it in the annexed Drawings, in which Figure 1 represents a
front elevation, and Figure 2 a plan of the meter, the working parts
being indicated by dotted lines. Figure 3 is a vertical section of the
same on lines 1, 2, 3, 4, 5, 6, Figure 2, which will illustrate the action
of one pair of these oscillating measuring chambers, of which there are
two pairs working in distinct compartments, as in the case of dry
meters.
Figure 4 is a section on line 7, 8, Figure 3, and Figure 5 is a section
on line 9, 10, 11, and 12.
Each pair of chambers oscillates on a horizontal axis, and is con-
structed of two side pieces of sheet metal of the form indicated by lines
a, b, b¹, a¹, c, c', and are fixed on a common spindle d mounted on
bearings, and connected by other pieces of sheet metal bent to the
form indicated by the lines c, a, b, e, c¹, a¹, b¹, e¹, which complete the
pair of curved chambers. f, f', is the level of the water in which these
chambers dip, and g is a diaphragm extending down nearly to the
spindle d, so that each oscillating chamber will be in a distinct com-
partment.
Communication is effected beneath the diaphragm by means of two
inverted syphon tubes h, by which the interiors of the oscillating
chambers are made to communicate with the opposite compartments
as shown.
The gas first enters a compartment i at the top of the meter, in which
are two slide valves j (one for each pair of oscillating chambers.) In
the position of the valve shown in Figure 3 the gas enters the com-
partment on the left hand and exerts its pressure on the oscillating
chamber a, b, therein, at the same time that it passes by the siphon h
into the interior of the other oscillating chamber a', 6', which it raises.
On the descent of chamber a, b, the gas contained therein is expelled
through the other siphon into the right-hand compartment, and together
with the volume of gas displaced by the chamber a¹, b¹, on rising is
caused to pass out through the valve j into the transverse passage k, and
thence into passage x, to be conveyed to the burners. Thus at each
oscillation the volume of gas contained in both oscillating chambers
is passed through the meter. It is of importance that the pair of
oscillating chambers should be in perfect equilibrium in all positions,

page_text: that is to say, that although partly immersed in water, as shown, they
shall not tend to move in one direction or the other when not acted on
by the pressure of the gas. It will be evident that this is essential to the
maintenance of a steady light. If the oscillating chambers were not
immersed in liquid it would be sufficient to attach weights so that the
centre of gravity should coincide with the axis of oscillation; but in
order to allow for the floating power of the water it is necessary that the
centre of gravity should be at such a point above the axis that its
movement relatively to the axis shall compensate in every position the
moments of force of the floating power of the water. This result may
be readily attained by calculation when the moment of the centre of
gravity of the pair of oscillating chambers, their form, and the thickness
and density of the metal of which they are made, are known. As before
mentioned there are two pairs of oscillating chambers in adjacent
compartments l, m, (Figures 2, 4, and 5), formed by partitions n, o, p,
(Figure 4), on which the axes of said chambers are mounted.
Figure 1 shows the position of the one pair of oscillating chambers
when the other pair is in the position shown in Figure 3.
To the pair of oscillating chambers are jointed two connecting rods, of
which one q is coupled to and operates the crank shaft r, whose cranks
are at right angles to one another and connected by rods q², each to a
slide valve j, so that when one of the pairs of chambers arrive at the end
of its course the other will be at the middle, and vice versa, as in dry
meters.
The other connecting rod passes through the vertical tube 8 and
operates the counting mechanism at t, by which the number of oscilla-
tions and consequently the volume of gas passed through the meter are
registered. n is the gas inlet, and a float and valve as usual, and the
transverse passage & extends across from n to p. The siphon tubes h are
fixed to the bottom of the apparatus, and communicate by means of
apertures y with a channel z (Figures 3, 4, and 5) in connection with a
vertical cylinder enclosing a syphon level w. The water enters this
cylinder by an overflow pipe 1, which regulates the maximum level of
water in the apparatus, the water being introduced therein at pipe 2
(Figures 1 and 2), and when it exceeds the level assigned to it by
pipe 1 it passes down into the cylinder, and thence through the channel
z to the syphons-h, until it reaches the level of syphon w, after which
.

page_text: the water passes out through pipe 3, whereupon the supply is arrested
and the apparatus is ready for use.
To prevent any condensation accumulating in passage k there is a
small tube 4 attached, dipping down into the water, as shown in Fig. 4.
I will now describe improved hydraulic valves which are chiefly
intended for large meters.
Figure 6 represents a plan of the valve chamber. There are two
hydraulic valves for each pair of oscillating measuring chambers, the
one for governing the inflow of gas to the compartment containing the
measuring chambers, and the other for the outflow from the said
chambers to the consumer. a and b are the two inlet valves for the two
pairs of oscillating measuring chambers, and c, c, are the two outlet
valves, the latter being enclosed in a separate compartment formed by
partitions d, e, f, g; h, gas inlet, and i, outlet.
The construction and operation of the valvo is shown in section,
Figure 7, taken on line 1, 2, Figure 6. It consists of a semi-cylindrical
cover j, k, l, mounted to oscillate on an axis m over a double passage
leading to the two compartments containing a pair of oscillating
measuring chambers. This cover dips in water, as shown, and has a
mid partition, also dipping in water, between the double passage, so as to
divide the cover into two parts, so that when the cover is oscillated to
the left, as shown in Figure 9 (which is a section on 3, 4, Figure 6),
the communication of the left-hand passage is cut off, and that of the
right-hand passage opened, and vice versa, when it oscillates to the right.
These valves are coupled two-and-two, a, c, b, c, and operated from crank
shaft p acting by connecting rods q on valves a, b, only, which valves
act in their turn on valves c, c.
The coupling of the valves and their action is as follows:-Take a and
c for example. A short shaft is mounted in bearings and passes through
an opening in partition f, g, below the water line n, and at the same
level as the axis m. This shaft has two crank arms, one on either side
of f, g. The one is connected by a rod, with a stud on the side of the
valve cover a, as shown in Figure 7. The other crank arm is similarly
connected (as shown in Figure 9, which is a section in line 3, 4,
Figure 6) to a stud on the side of valve c, as shown, so that when the
short shaft turns in direction the axis of valve c shall turn in the
reverse direction.
The valves are so arranged that when valve a closes

page_text: The valve chamber may be fitted with a gauge to show the water
level. More than two pairs of oscillating measuring chambers may be
used if necessary.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 1st September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of March, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Alexander Melville Clark, Her special licence
that I, the said Alexander Melville Clark, my executors, administrators,
and assigns, or such others as I, the said Alexander Melville Clark,
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 Ireland, the Channel Islands, and Isle of Man, an Inven-
tion for "IMPROVEMENTS IN GAS METERS," a communication to me from
abroad by Edouard Armand Robert d'Hurcourt, of Paris, France, upon
the condition (amongst others) that I, the said Alexander Melville
Clark, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should parti-
cularly 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 Alexander Melville Clark, do hereby
declare the nature of my said Invention, and in what manner the same

page_text: is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the two accom-
panying Sheets of Drawings, and to the letters and figures marked
thereon (that is to say) :-
This Invention relates to improvements in gas meters, and consists
mainly in the employment of pairs of measuring chambers or gas-
holders, dipping in water, and mounted to oscillate on an axis, so as to be
filled and emptied alternately with gas.
In order that the Invention may be more readily understood I have
illustrated it in the annexed Drawings, in which Figure 1 represents a
front elevation, and Figure 2 a plan of the meter, the working parts
being indicated by dotted lines. Figure 3 is a vertical section of the
same on lines 1, 2, 3, 4, 5, 6, Figure 2, which will illustrate the action
of one pair of these oscillating measuring chambers, of which there are
two pairs working in distinct compartments, as in the case of dry
meters.
Figure 4 is a section on line 7, 8, Figure 3, and Figure 5 is a section
on line 9, 10, 11, 12, Figure 4.
Each pair of chambers oscillates on a horizontal axis, and is con-
structed of two side pieces of sheet metal of the form indicated by lines
a, b, b¹, a¹, c, c¹, and are fixed on a common spindle d mounted in
bearings, and connected by other pieces of sheet metal bent to the form
indicated by the lines c, a, b, e, c¹, a¹, b', e¹, which complete the pair of
curved chambers. f, f¹, is the level of the water in which these
chambers dip, and 9 is a diaphragm extending down nearly to the
spindle d, so that each oscillating chamber will be in a distinct
compartment.
Communication is effected beneath the diaphragm by means of two
inverted syphon tubes h, by which the interiors of the oscillating
chambers are made to communicate with the opposite compartments,
as shown.
The gas first enters a compartment i at the top of the meter, in which
are two slide valves j (one for each pair of oscillating chambers.) In
the position of the valve shown in Figure 3 the gas enters the compart.
ment on the left hand and exerts its pressure on the oscillating chamber
a, b, therein at the same time that it passes by the syphon h into the

page_text: interior of the other oscillating chamber a¹, 6¹, which it raises. On the
descent of chamber a, b, the gas contained therein is expelled through
the other syphon into the right-hand compartment, and, together with
the volume of gas displaced by the chamber a¹, b¹, on rising, is caused to
pass out through the valve j into the transverse passage k, and thence
into pipe x, to be conveyed where required for consumption. Thus at
each oscillation the volume of gas contained in both oscillating chambers
is passed through the meter. It is of importance that the pair of
oscillating chambers should be in equilibrium in all positions, so that,
although partly immersed in water, as shown, they shall not tend to
move in one direction or the other when not acted on by any disturbing
force. It will be evident that this essential to the maintenance of a
steady light. If the oscillating chambers were not immersed in liquid it
would be sufficient to attach weights so that the centre of gravity should
coincide with the axis of oscillation, but in order to allow for the floating
power of the water it is necessary that the centre of gravity should
be at such a point above the axis that its moment relatively to the axis
shall compensate in every position the moment of forces resulting from
the upward pressure of the water. This result may be readily attained
by calculation when the moment of the centre of gravity of the pair of
oscillating chambers, their form, and the thickness and density of the
metal of which they are made are known. As before mentioned, there
are two pairs of oscillating chambers in adjacent compartments l, m,
(Figures 2, 4, and 5), formed by partitions n, o, p, (Figure 4), on which
the axes of said chambers are mounted.
Figure 1 shows the position of the one pair of oscillating chambers
when the other pair is in the position shown in Figure 3.
To the pair of oscillating chambers are jointed two connecting rods,
of which one q is coupled to and operates the crank shaft ", whose
cranks are at right angles to one another and connected by rods q¹ each
to a slide valve j, so that when one of the pairs of chambers arrives at
the end of its course the other will be at the middle, and vice versa, as
in dry meters.
The other connecting rod passes through the vertical tube 8 and
operates the counting mechanism at t, by which the number of oscilla-
tions, and consequently the volume of gas passed through the meter, are
registered. u is the gas inlet, and v a float and valve as usual. The

page_text: transverse passage k extends across from n to p. The syphon tubes
are fixed to the bottom of the apparatus, and communicate, by means of
apertures y, with a channel z (Figures 3, 4, and 5), in connection with a
vertical cylinder enclosing a syphon level w. The water enters this
cylinder by an overflow pipe 1, Figure 1, which regulates the maximum
level of water in the apparatus, the water being introduced therein at
pipe 2, Figures 1 and 2, and when it exceeds the level assigned to it by
pipe 1 it passes down into the cylinder and thence through the channel
z to the syphons 7 until it reaches the level of syphon w, after which the
water passes out through pipe 3, whereupon the supply is arrested and
the apparatus ready for use.
To prevent any condensation accumulating in passage
there is a
small tube 4 attached, dipping down into the water, as shown in
Figure 4.
The following are the advantages of this improved meter,-
1st. It absorbs but very little pressure in working, in fact the
resistance of the water is almost nil, and that produced by the working
of the valves is but slight, at all events in the consumer's meters. For
station meters hydraulic valves absorbing but very slight pressure are
employed, as will be herein-after described.
2nd. It indicates the volume of gas passing through without being
influenced in the least by differences in the water level, as is the case
with ordinary meters, the outflow varying only with the extent of
motion of the measuring chambers, which is constant, whatever may be
the water level.
3rd. It is of much smaller dimensions for a given rate of supply than
the Crosley meter. Thus, suppose the number of oscillations to be
limited to 1,000 per hour, as each oscillation corresponds to a traverse of
50 degrees even in the small meters, this represents a total of 50,000°
per hour, which really corresponds to a supply of 100,000° in the
Crosley meter. As this improved meter affords a double supply for the
same number of degrees traversed, whereas the Crosley meter at 360°
revolution, and 100 revolutions per hour can only supply a volume of
gas equal to 36,000°. The meter illustrated in the Drawing supplies at
each oscillation per hour 85,433 cubic inches, or for 1,000 oscillations
per hour 85,433 cubic inches, sufficient for the supply of 10 burners.

page_text: I will now describe improved hydraulic valves which are chiefly
intended for large meters, such as station meters.
Figure 6 represents a plan of the valve chamber. There are two
hydraulic valves for each pair of oscillating measuring chambers, the
one for governing the inflow of gas to the compartment containing the
measuring chambers and the other for the outflow from the said
chambers. a and b are the two inlet valves for the two pairs of
oscillating measuring chambers, and c, c, are the two outlet valves, the
latter being enclosed in a separate compartment formed by partitions
d, e, f, g; h, inlet for the gas which passes to the measuring chambers
through valves a, b, and is afterwards received in closed chamber d, e,
f, g, through valves c, c², and passes to the burners at outlet i.
The construction and operation of the valves is shown in section,
Figure 7, taken on line 1, 2, Figure 6. It consists of a semi-cylindrical
cover j, k, l, mounted to oscillate on an axis m over a double passage
leading to the two compartments containing a pair of oscillating
measuring chambers. This cover dips in water, as shown, and has a
mid-partition, also dipping in water, between the double passage so as to
divide the cover in two parts, so that when the cover is oscillated to
the left, as shown in Figure 9 (which is a section on line 3, 4, Figure 6)
the communication of the left-hand passage is cut off, and that of the
right-hand passage opened, and vice versa, when it oscillates to the
right. These valves are coupled two and two, a with c, and 6 with c,
operated from crank shaft p acting by connecting rods q on valves a, b,
only, which valves act in their turn on valves c, c.
The coupling of the valves and their action is as follows:-Take
a and c for example. A short shaft is mounted in bearings and passes
through an opening in partition f, g, below the water line n, and at the
same level as the axis m. This shaft has two crank arms, one on either
side of f, g. The one is connected by a rod with a stud on the side
of valve cover a, as shown in Figure 7. The other crank arm is
similarly connected (as shown in Figure 9, which is a section on 3, 4,
Figure 6) to a stud on side of valve c, as shown, so that when the
short shaft turns in one direction the axis of valve c shall turn in the
reverse direction. The valves are so arranged that when valve a closes
both passages, valve c also closes its two passages, similarly for valves
hand c

page_text: The valve chamber may be fitted with a gauge to show the water level.
More than two pairs of oscillating measuring chambers may be used if
necessary.
In describing the particular construction of the pairs of measuring
chambers, and the advantages resulting from their use, I have herein-
before mentioned that each pair should be equilibrated by means of a
weight fixed thereto in a medium line passing through the axis in such
manner that the measuring chamber, when immersed, will have no
tendency, in whatever position it may assume, to oscillate to the one side
or the other. The weight to be employed may be determined by
calculation, but it is preferable to immerse each measuring chamber in
the water by oscillating it on its axis, and then modify the weight until
the desired state of equilibrium is obtained. The weight may be so
much the less the more distant it is placed from the centro, the
advantage of which is that the measuring chamber will be reduced in
weight. For this purpose, instead of uniting the two measuring
chambers by means of side plates, as described, I connect them together
by two arms of tin plate soldered to the same at the front and back
respectively. The spindle traverses these two arms. To the under part
of one of the arms in the median line is soldered a stem made of tin
plate, at the lowest point of which is fixed a counterbalance weight
serving to maintain the equilibrium of the measuring chambers. I have
also described one method of transmitting the oscillatory motion of the
measuring chambers to the counter. The same result may also be
produced by placing the counting mechanism outside of the casing
instead of inside, as shown. In this arrangement a spindle passing
through a stuffing box, as in dry meters, communicates with the
mechanism from inside the casing, the said spindle which operates the
pointers, having mounted upon it, inside the casing a wheel, set in motion
by an endless screw mounted on a cross shaft, having at its opposite end
a wheel receiving motion in its turn from another endless screw on the
crank shaft for working the valves, and indicated in the Drawings by
the letter r. I may also, to simplify the construction, combine the float
carrying the inlet valve and the syphon in one casing, placed in front of
the meter as in ordinary. The syphon being on the right as usual is
enclosed in a casing, the upper part of which determines the water level
in the meter. The water supplied in excess thus falls into this casing,
which communicates by a lower channel with the bends of the pairs of

page_text: measuring chambers and isolates the same. When the water rises
above the line determined by the syphon it flows out as in ordinary
meters.
Having described the nature of the Invention and the manner of
performing the same, I declare that what I claim as the Invention to be
protected by the herein-before in part recited Letters Patent is,-
1st. The particular arrangement of pairs of oscillating chambers for
measuring the gas, substantially as described and illustrated.
2nd. The particular arrangement of hydraulic valves, either simple or
coupled, as shown and described, whereby the resistance due to their
working is limited to the mere friction of the spindle, thus permitting
the use of meters of unlimited dimensions without any appreciable less
of pressure.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this First day of September, in
the year of our Lord One thousand eight hundred and seventy-
five.