IMPROVEMENTS IN WET GAS METERS
Year: 1878

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 WET GAS METERS." A communication from abroad by the Firm of Siry-
Lizars and Company, of Paris, France.
Sealed the 9th July 1878, and dated the 19th January 1878.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 19th January 1878.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middle-
sex, Patent Agent. "IMPROVEMENTS IN WET GAS METERS." [A communication
from abroad by the Firm of Siry-Lizars and Company, of Paris, France.]
This Invention relates to improvements in wet gas meters, and consists in the
employment of a compensating measuring drum, by which the amount of gas passing
is always accurately registered independently of the varying level of the water.
The objection to the common description of gas meter is that, although it registers
correctly with the water at a certain level, when the water line falls the compart-
ments receive and deliver more gas at each revolution of the drum, and the index
consequently registers less gas than has actually passed through the meter. This
objection is obviated by this Invention, which consists, mainly, in making the
several compartments communicate with each other in such manner that when
the water line falls below the proper height the gas in excess of the normal quantity
each compartment contained with the water at its proper level is transferred from
each compartment as it is filled to the next one being filled. Thus the variation of
the water level is compensated, and the drum always delivers the same amount of
gas at each revolution, and the meter consequently registers correctly at all times.
This system of compensation may be applied to all kinds of wet gas meters.

page_text: The Invention is illustrated by way of example in the accompanying Drawings,
in which,-
Figure 1 shows a face view of the drum; Figure 2, a plan; and Figure 3, a
section, taken on line 1-2, Figure 1.
Figures 4 and 5 are sections on lines 3-4 and 5-6, Figure 2, respectively.
The same letters of reference indicate the same parts in all the Figures. .
gas
a, drum, divided into four compartments by inclined partition plates b, as usual;
c, front end of the drum, through which the gas passes into the compartments; d,
back end of drum, with passages for the egress of the gas to the outlet; e, drum
spindle; g, convex cover at which the gas is introduced by the syphon tube, and
whence it passes into the drum; f, f, are four inverted U shaped troughs or
channels, placed parallel in pairs at right angles the one pair to the other, by which
the several compartments of the drum are placed in communication with each other.
These channels as they emerge in succession above the water conduct the in
excess of the normal quantity from the filled compartment into the next one being
filled, and thus compensate for the fall of the water level, as above described. The
greater the fall the more gas transferred by the channels, but the dimensions of
the latter should be such that the channels will receive above the water line a
volume of gas equal to the increase in the capacity of the compartments by the fall
of the water level. The channels may be of any suitable form or section, and be placed
in the position shown or inclined. They may also be made to extend through two
compartments instead of one; the gas may be admitted at the circumference a
instead of through front c as usual; the channel being in this case enclosed on the
under side from the opening in the circumference to the centre of the drum.
I will now describe a modified arrangement of the channels. Each channel f
traverses two partitions, and is shorter than those shown in Figures 1, 2, 3, 4, and 5.
The length of the channels may be reduced without increasing their breadth, as
owing to the position which they occupy in the compartment where the gas is
measured the surface of water which they enclose is depressed by a fall in the
level, and the volume of the gas to be transferred is consequently reduced.
Figures 6, 7, 8, and 9 show sectional elevations of the interior only of a measuring
drum with its partitions and the channels connecting the opposite compartments,
which constitute the Invention, the passages for the admission and exit of gas,
&c., being omitted, the motion of the drum being in the direction indicated by the
arrows, and the water line being at m, n.
The channel shown in action in the Figures, viz., that connecting the compart-
ments A and C, and traversing the intermediate compartment B, transfers the
excess of gas from A to C in the following manner :- -When the channel is in the
position shown in Figure 8 the gas it contains occupies the space a, b, c, and the
rotary motion being continued until a small orifice c¹ at the opposite end of
the channel rises above the water as in Figure 9; the gas then occupies the space
b, c, c', which being rather smaller than space a, b, c, as will be presently explained,
the pressure of this volume of gas is therefore slightly increased so as to be about
equal to the pressure of the gas in compartment C. Should there be any slight
difference in these pressures it will be equalized as soon as the channel and com-
partment communicate by orifice c¹, so that the end of the channel may leave the
water without causing any agitation.
The increase in the pressure of the gas after it enters the channel is caused by
an enlargement a, b, c, formed at the inlet end of channel, Figure 8, so that the gas
when it first enters the channel occupies the spaces a, b, i, and i, b, c, and when the
channel assumes the position indicated in Figure 9 its capacity becomes contracted
to the space b, c, c', which is equal to i, b, c, and as the channel still contains the
extra volume of gas which filled a, b, i, there will consequently be an increase of
pressure.
The volume a, b, i, is calculated so that the increase of pressure shall equal from
two to three millimetres, which is the difference in pressure of the gas in the com-

page_text: partments C.and A, and as C communicates with the gas inlet and A with the
outlet these two or three millimetres represent the pressure absorbed by the working
of the meter.
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
18th July 1878.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middle-
sex, Patent Agent. "IMPROVEMENTS IN WET GAS METERS." A communication
from abroad by the Firm of Siry-Lizars and Company, of Paris, France.
This Invention of improvements in wet gas meters relates to a compensating
measuring drum by which a uniform amount of gas is passed through the meter
notwithstanding any variation in the level of the water, so that the meter always
delivers the quantity registered and no more.
The common description of gas meter, although it registers correctly when the
water is at the proper height, is open to the objection that when in consequence of
evaporation the water line falls below that level the capacity of the compartments
is increased, and they then receive and deliver more gas at each revolution of the
drum than before, so that the index consequently registers less gas than has actually
passed through the meter. This objection is obviated by this Invention, which
consists, mainly, in making the several compartments communicate in such manner
that when the water line falls below the proper height the gas in excess of the
normal quantity which each compartment could contain when the water was at its
proper level becomes transferred from the filled compartment to the next one being
filled. Thus any variation of the water level is compensated, and the drum always
delivers the same amount of gas at each revolution, and the meter consequently
registers correctly at all times. This system of compensation may be applied to all
kinds of wet gas meters.
The Invention is illustrated by way of example in the accompanying Drawings,
in which,
Figure 1 shows a face view of the drum, removed from the outer case of the
meter; Figure 2, a plan; and Figure 3, a section, taken on line 1-2, Figure 1.
Figures 4 and 5 are sections on lines 3-4 and 5-6, Figure 2, respectively.
The same letters of reference indicate the same parts in all the Figures..
a is the drum, divided into four compartments by inclined partition plates b, as
usual; c, front end of the drum, through which the gas passes into the compart-
ments; d, back end of drum, with passages for the egress of the gas to the outlet ;
€,. drum spindle; g, convex cover, at which the gas is introduced by the syphon
tube, and whence it passes into the drum; f, f, are four U shaped troughs or
channels placed in pairs, the two troughs of each pair. being face to face and parallel,
and the one pair being at right angles to the other. By these troughs the several
compartments of the drum are placed in communication with each other; as shown.

page_text: These channels as they emerge in succession above the water are inverted, thus n
and each serves to couduct the gas in excess of the normal quantity from the filled
compartment into the next one which is being filled, thus compensating for the fall
of the water level, as above described. The greater the fall the more gas is trans-
ferred by the channels, the dimensions of the latter being such that they will receive
above the water line a volume of gas equal to the increase in the capacity of the
compartments due to the fall of the water level. The channels may be of any
suitable form or section, and may be placed in the position shown, or inclined as
hereafter described; they may also be made to extend through two partitions
instead of one, and thus connect alternate compartments. The gas may be admitted
through apertures in the circumference a instead of through the front c as usual;
the channels being in this latter case enclosed on the under side from the opening
in the circumference a to the centre of the drum.
I will now describe a modified arrangement of the channels. Each channel f
traverses two partitions, and is shorter than those shown in Figures 1, 2, 3, 4, and 5.
The length of the channels may be thus reduced without increasing their breadth,
as owing to the position which they occupy in the compartments through which
they pass they reduce the water surface of the compartments, and the volume of
the gas to be transferred in consequence of a fall of the water level is consequently
diminished..
! !
Figures 6, 7, 8, and 9 show sectional elevations of the interior only of a measuring
drum with its partitions and the channels connecting opposite compartments which
constitute the Invention, the passages for the admission and exit of gas, &c., being
omitted. The motion of the drum is in the direction indicated by the arrows, and
the water line at m, n.
The channel shown in action in the Figures, viz., that connecting the compart-
ments A and C, and traversing the intermediate compartment B, transfers the excess
of gas from A to C in the following manner:-When the channel is in the position
shown in Figure 8 the gas it contains occupies the space a, b, c, and the rotary
motion being continued until a small orifice c¹ at the opposite end of the channel is
about to rise above the water (as in Figure 9) the gas then occupies the space b, c, c¹,
which being rather smaller than space a, b, c, as will be presently explained, the
pressure of this volume of gas is therefore slightly increased so as to be about equal
to the pressure of the gas in compartment C. Should there be any slight difference
in these pressures it will be equalised as soon as the channel and compartment
communicate by orifice c¹, so that the end of the channel may leave the water with-
out causing any agitation.
The increase in the pressure of gas after it enters the channel is caused by an
enlargement or hood a, b, e, formed at the inlet end of the channel (see Figure 8),
so that the gas when it first enters the channel occupies the spaces a, b, i, and i, b, c,
and when the channel assumes the position indicated in Figure 9 its capacity
becomes contracted to the space b, c, c', which is equal to i, b, c, and as the channel
still contains the extra volume of gas which filled a, b, i, there will consequently be
an increase of pressure.
The volume a, b, i, is calculated so that the increase of pressure shall equal from
two to three millimetres, which is the difference in pressure of the gas in the compart-
ments C and A, and as C communicates with the gas inlet and A with the outlet
these two or three millimetres represent the pressure absorbed by the working of
the meter.
Having described the nature of the said 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. A gas meter measuring drum in which every two adjacent or successive
compartments thereof are connected by an arrangement of channels, substantially
as herein described, and shown in Figures 1, 2, 3, 4, 5 of the Drawings, for the
purpose specified.
2nd. A gas meter measuring drum in which every two alternate or opposite

page_text: compartments are connected by an arrangement of channels, substantially as herein
described, and shown in Figures 6, 7, 8, and 9 of the Drawings, for the purpose
specified, whereby greater steadiness of light is ensured.
3rd. Constructing the channels connecting the alternate compartments of a gas
meter measuring drum, as described in Figures 6, 7, 8, and 9, with the enlargements
or hoods a, b, e, at the forward ends of the said channels, as and for the purpose
specified.
4th. Providing the troughs or channels connecting the alternate compartments of
a gas meter measuring drum with orifices c¹at the rear ends, substantially as and
for the purpose specified.
In witness whereof, I, the Alexander Melville Clark, have hereunto set my
hand and seal, this Eighteenth day of July, in the year of our Lord One
thousand eight hundred and seventy-eight.
A. M. CLARK. (L.B.)