IMPROVEMENTS IN GAS METERS
Year: 1858

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the County
of Middlesex, Engineer and Patent: Agent, for the Invention of "IM-
tion
PROVISIONAL SPECIFICATION left by the said William Clark at the
Office of the Commissioners of Patents, with his Petition, on the 8th
March 1858.
J.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN GAS METERS," to be as follows:-
This Invention relates to several arrangements which render the use of the
hydrostatic tube a, Figures 1, 2, 3, and 4, easily practicable for establishing the
constant level of the water in gas meters. This result is obtained by neutral-
izing the various causes which have hitherto prevented the use of this tube.
in spite of the simplicity of the principle on which it is based.
First, I establish the action of the tube by causing it to dip in the water in
the anterior case of the meter, and by piercing it with a hole a of the shape
represented, the upper part of which is at the level at which the tube is to
act. In this manner, at the same time that the bubble of gas leaves through.
a, the water enters through the lower aperture b, without one of these.
movements disturbing the other.

page_text: Secondly, I invariably unite the hydrostatic tube a to the overflow part c in
the desired position, and give a certain elasticity to this tube, which allows of
its lengthening or shortening. Hence it results that by raising or lowering
the overflow part, in order to regulate the meter, the suitable regulation of the
hydrostatic tube takes place without having to regulate it separately.
Thirdly, I insulate the hydrostatic tube a by encasing it, for example, with
a large tube d, closed at the bottom, and pierced with a small hole m, the
principal object of which is to obviate the serious inconveniences which
result in ordinary cases from the capillary attraction, the level of the water in
the anterior case of the meter falls, in fact, below the upper part of aperture a
before this part is uncovered by reason of a meniscus or curved rising of the
water e round the hole, see Fig. 4, which rises the length of the tube by the
capillary action. When the meniscus breaks, the level is found to be greatly
below aperture a, see Fig. 5, then for the first time the principle of constancy
in the level of the water is broken, but what is more serious there is a great
volume of water to be replaced at once by a series of bubbles succeeding each
other rapidly, and this produces great agitation in the water in the meter, and
consequently in the flame of the burners. The insulating tube completely
destroys this annoying perturbation, a single buble suffices to let the water
introduced rise in the tube above aperture a, this water then leaves slowly
through m, and the level between the interior and exterior is re-established,
but in its downward movement it has re-established the capillary meniscus,
and one bubble suffices to return everything to its original state.
Fourthly, the great difference of pressure which is necessarily established
for a short moment between the two cases of the meter when the cocks are
opened has to be obviated. The gas has then to overcome the vis inertia of
the wheel or moving part, and its accessaries, in order to put it in motion.
Hence the lowering of the level in the anterior case which receives the gas,
and the raising of the level in the hinder case, whence it escapes. I have
restricted the communication between these two compartments to the smallest
proportions, in order that the pressure may not have the power to alter the
levels much during the very short time the inert resistance lasts. The
insulating tube, which may be in duplicate for this purpose, contributes to
maintain the constancy of the level near the exit aperture of the gas.
The fifth arrangement remains to be described, which is perhaps the most
important of all. When two supposed reservoirs, Fig. 6, communicate by
a tube f, and the equilibrium is established, the difference between the
pressures P and P' is equal to the difference n, n', existing between the levels
of the water, so that P₁ = P.-n, n'. If P communicates with the atmo-

page_text: -sphere, and the upper reservoir is not hermetically closed, the lower reservoir
will be filled infallibly. In order to avoid ordinary corks, which are never
secure, and which the consumer may tamper with, I fill the upper reservoir
by a syphon A, A, A, placed in the apparatus, but which I have shown on the
exterior in order to render its action more intelligible. This syphon opens
into the top of the reservoir; it descends below the level of the anterior case.
During the filling the gas leaves first and then the water follows through
tube B, B, also placed in the interior, and which opens to the little box t,
intended to form a hydraulic closure. This little box has its exit aperture
at s at the upper part, while the pipe B dips to the bottom. If the filling
aperture k and the exit aperture for the gas s be opened during the action, the
water will be maintained in the two tubes, for there will be o', 0, s, n, =
n, n¹, and the air cannot penetrate into the reservoir.
Having thus described the several new arrangements for enabling and
effecting the use of the hydrostatic tube when it communicates with the
anterior reservoir, I will further add, that in consideration of certain advan-
tages presented by the communication of the said tube with the hinder
reservoir, we reserve to ourselves the principle involved in this new kind of
communication.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Clark in the Great Seal Patent Office on the
8th September 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLARK; of 53, Chancery Lane, in the County of Middlesex, Engineer. &
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of March, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Clark, Her special licence that I, the said William
Clark, my executors, administrators, and assigns, or such others as I, the
said William 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

page_text: Ireland, the Channel Islands, and Isle of Man, an Invention. for "IMPROVE-
MENTS IN GAS METERS," (a communication,) upon the condition (amongst
others) that I, the said William Clark, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and seals,
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 Clark, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
*statement, reference being had to the Sheet of Drawings hereunto annexed,
& to the letters & figures marked thereon (that is to say):
1 The object of the present Specification is to indicate several arrangements
'whereby the hydrostatic tube may be employed in gas meters; it has often
'been attempted to employ the hydrostatic tube in gas meters for maintaining
the level of the water constant, but it has always presented such incon-
veniences in its application as to necessitate its being abandoned. These
inconveniences have been studied with great care & observation, & the
arrangements herein-after described discovered, which arrangements are
intended to obviate the defects alluded to.
The first of the inconveniences mentioned consists of the difficulty or it may
be the impossibility of maintaining the closing of the upper reservoir in a state
completely hermetical, which prevents the possibility of guarding against the
flooding of the meter. Moreover, supposing the closing to be quite hermetical,
if it were opened merely for curiosity or otherwise, it would be sufficient to
In the second
cause the water of the reservoir to descend into the meter.
place the hydrostatic tube has always been put in communication with the
front chamber of the meter, in which it causes, as is well known, a lowering
of the level of the water when the meter acts. This lowering is not always
the same, but increases in proportion as the quantity of gas supplied increases,
while for a uniform supply it becomes impossible to regulate the level exactly if
the parts in motion become foul.
In the arrangement above alluded to the renewing of the water is effected
during the passage & combustion of the gas, which results in this further
inconvenience, the level of the water becomes sensibly lowered in the anterior
chamber of the meter below the orifice before the breaking of the meniscus or
bubble, which conducts the lower water to the tube by reason of its capillary

page_text: action, the level being obtained by a descent; thus the water will not cease to
supply the tube for some time. When this capillary action is overcome, there
will be a considerable void to fill up, which produces a succession of bubbles,
agitating the gas, & communicating to the flame at the burners a disagreeable
& very objectionable movement. Moreover, at the time of putting the meter
in motion, when the
the inertia of the moveable parts of
gas should overcome
the meter (the wheel & train), it produces an extraordinary lowering of the
level of the water, the hydrostatic tube becomes immersed,. & a volume of
water enters the meter & alters the level, which it is desired to render as
constant as possible. Another inconvenience resulting from the arrangements
hitherto adopted consists in the separation of the overflow tube & of the hydro-
static tube, a separation which renders the regulation excessively difficult.
The following description of apparatus shows how the principal difficulties
before mentioned, & others which present themselves, are overcome. The
upper reservoir A (Figs. 1, 2, 3), is filled by means of a syphon a, a, a, the
upper orifice of which may be furnished with a small funnel b, the opening
being closed by a screw plug c, in proportion as water is poured in the funnel 6
.it passes into the reservoir A; the gas contained in this reservoir will escape
by the tube d, & entering into the box or compartment B, escapes by the tube
e, care being taken to remove the plug f. When the reservoir A is filled with
water, the water follows the same course as the gas, & passes out by the lower
orifice of the tube e; when this takes place the supply of water is stopped, &
the plugs f&c replaced. During the filling it is necessary to close the stop-
cock on the inlet passage of the gas & that of the escape, as in this operation
the pressure will be slightly augmented, which produces a little elevation in
the level, but which can be rectified by opening the overflow passage, as in
ordinary gas meters, every time that water is poured into the meter, although
it is better usually to keep the plugs c & f in position; they may at all times
be removed without inconvenience, the tubes a, a, & d, d, forming of them;
selves a hydraulic closure by the known action of syphons; this mode of supply
prevents the meter being filled too full of water.
Secondly, although the hydrostatic tube c, c', is placed in the front chamber,
it is put in communication with the binder compartment by the opening h
(Fig. 4), & separated from the front case by means of a small square partition
9, 9, 9, the lower part of which partition dips in the water. The effect of
this disposition & arrangement is this, during the action & at the same moment
as the agitation takes place, which lowers the level of the water in the front
compartment, the level rises round the tube & covers the orifice without causing

page_text: any inconvenience. If at the moment when the light is extinguished there has
been any dissipation of the water, & as a consequence a slight lowering of
the level, it is immediately re-established without inconvenience. At all times
the effect of the capillary attraction mentioned causes a slight difference in the
level, but it may be remedied by placing the hydrostating tube c, c, in a tube
i, i, i, of a rather larger diameter, closed at bottom & communicating with
'the water of the front compartment by a small hole k. When the meniscus
breaks, a single bubble of gas escaping will bring into the tube i a sufficient
'volume of water to cover the orifice m, when the level is gently re-established
by means of the flow through k, & the meniscus due to the capillary action
is again formed at 7; from that time the water is maintained at a constant level,
& this at all times while working with either a large or small supply, &
when the supply is cut off, the level of the water re-establishes itself with
mathematical precision.
Lastly, in order to render regulation easy the overflow pipe D, the isolating
tube i, & the hydrostatic tube or rather the lower part c² of this tube are
invariably joined together, so that when experience has determined the relation
between the height required by the capillary action & the height of the over-
flow & the orifice m, the parts are united in their proper relative positions.
The regulation of the meter may thus be effected in the ordinary manner by
altering the level of the overflow.
The overflow has been described as being united to the lower part of the
hydrostatic tube, for which purpose this tube is composed of two distinct parts,
the upper part c of which is fixed, & the lower part c² having the orifice m
slides loosely on the upper part, which also serves as a guide. This arrange-
ment is of great importance, inasmuch as it destroys the resistance that the
hydrostatic tube would present to the free action of the overflow, when regu-
lating it, & which arrangement also allows of the hydrostatic tube being in a
vertical position. It may also be observed, that the form given to the orifice m,
& which in Fig. 4 is rendered sufficiently clear, is peculiarly favorable to the
quiet exit of the bubbles.
Having described the nature of this Invention, & the manner of performing
the same, I declare that what I claim as the Inventor to be protected by the
herein-before in part recited Letters Patent is,-
1st, the mode of introducing the water & the exit of gas in the upper
reservoir, as described.
2ndly, the communication of the hydrostatic tube with the back compart-
ment of the meter.

page_text: 3rdly, the isolating tube with which the lower part of the hydrostatic tube is
enclosed.
4thly, the connection between the hydrostatic tube & the overflow, with a
view of rendering easy the regulation of the meter.
5thly, the dividing the hydrostatic tube into two parts, one sliding on the
other, which arrangement has the advantage of facilitating the regulation by
keeping the tube in a vertical position.
In witness whereof, I, the said William Clark, have hereunto set my
hand and seal, this Seventh day of September, in the year of our
Lord One thousand eight hundred and fifty-eight.
W. CLARK.
(L.S.)