IMPROVEMENTS IN GAS METERS
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
CLEGG, of Regents Square, in the County of Middlesex, Engineer, send
greeting.
WHEREAS Her pr
Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twentieth day of April,
One thousand eight hundred and forty-eight, in the eleventh year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Samuel Clegg, my exors, adññiors, and assigns, Her especial licence, full
power, sole privilego and authority, that I, the said Samuel Clegg, my exors,
adiñors, and assigns, or such others as I, the said Samuel Clegg, my exors,
adiñiors, or assigns, should at any time agree with, and no others, from time
to time and at all times during the term of years therein expressed, should
and lawfully might make, use, exercise, and vend, within England, Wales,
and the Town of Berwick-upon-Tweed, my Invention of "IMPROVEMENTS IN
GAS METERS;" in which said Letters Patent is contained a proviso that I,
the said Samuel Clegg, should cause a particular description of the nature of
my said Invention, and in what manner the same is to be performed, by an
instrument in writing under my hand and seal, to be inrolled in Her Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said in part recited Letters Patent, as in and by
the same, reference being thereunto had, will more fully and at large appear.
NOW KNOW YE,. that in compliance with the said proviso, I, the said
Samuel Clegg, do hereby declare that the nature of my Invention consists

page_text: of Improvements in Gas Meters, the particular object of which improvements
is to effect in a more perfect and complete manner than has hitherto been
done the measurement of coal or oil gas, or other gaseous fluids.
And in further compliance with the said proviso, I, the said Samuel Clegg,
do hereby declare that the manner in which my said Invention is to be per-
formed and carried into effect is set forth and ascertained by the Drawings
hereunto annexed, and the descriptions thereof herein-after contained.
In the annexed Drawings the same letters and figures in the different sections
and views represent the same parts throughout, and the scale to which the
several sections and views are drawn are marked on the sheets. In the
annexed Drawings several parts of a gas meter are represented which I have
not described, such as the measuring drum of the water meter and the
measuring diaphragms of the dry meter, the inlet and outlet pipes and parts
of the case. These parts are well known to persons conversant with gas
meters; and I have merely introduced them in order better to explain the
nature of my improvements. It is a well known law of statics that the
discharges of the same fluid through different openings and under the same
pressure are proportional to the areas of those openings. If the quantity of
coal gas discharged through one opening be known, calculating by the above
rule, the quantity discharged through the other is known also, consequently
the total quantity discharged through both. Upon this law an improved
meter has been designed, and it has for its object to measure the quantity of
gas discharged through one of these two openings. In construction, one
opening is or may be made smaller than the other, and the quantity of gas
flowing through the small one measured.
Given the areas, I will now describe suitable mechanical contrivances for
applying this principle in the construction of gas meters.-The measuring
drum of what is called a wet meter consists of a hollow concentric ring and
cover (as in my original meter, patented in One thousand eight hundred and
fifteen). The drum revolving upon an axis in water is divided into compart-
ments so arranged that as the gas enters it shall in succession fill all the
chambers and be discharged measured. This portion not being claimed in
the present Patent, and being on the same principle as the water meters in
general use, will not be further described. The inner circle c, c, of the drum,
by means of the partition S, S, and the back plate T, T, which is secured to
the axis on which the drum revolves, is made water-tight, so that when the
meter is filled to a certain level with water the drum is buoyed up, and would
nearly float if otherwise unsupported, consequently there is little or no friction
upon the axis; and this water-tight chamber constitutes one of my improve-

page_text: ments. The gas from the service enters the meter case through the pipe K,
and after passing a valve which, when the meter is sufficiently filled with
water, is opened by a float in the usual way, is divided into two streams, and
flows through the pipes C and B', the latter stream being the one measured,
and is discharged or measured from the drum cover by the pipe P. through the
opening N. Now this discharge being known, the quantity of,
that passes
gas
through the other opening M is known also, and the sum of the two discharges
is marked on the face of an index arranged in the usual way. But it is
important that the discharges of the gas through these two openings N and M.
should always be at the same relative pressure. Now the gas discharged through
N has passed through the drum, and consequently the original pressure with
which the gas has entered the meter has been reduced by so much as is
required to work the drum; say, for the sake of illustration, this reduction is
equal to one tenth of an, inch head of water, then, if the original pressure be
four tenths, the gas will flow through N with a pressure of three tenths, and,
presuming no precautions taken to prevent it, the gas flowing through M
without obstruction would be discharged with the original pressure of four
tenths, or with one tenth more pressure than that discharged through N; and
this variation in the pressures would render the measure inaccurate. To
equalize the pressure the apparatus now to be described is used. E and H
are two hollow vessels connected with one another at their lower parts, open at
the bottom, scaled by water, and free to vibrate about a common centre X. V
is a slide covering the two openings M and N, attached to the hood H in such
a manner that as it rises or falls it shall move the slide V and open or close
these openings. The pipes A and B lead into these vessels or hoods, and the
gas discharged into them is of the same pressure as that which flows into tho
meter, which has been assumed at four tenths, so that if the regulating hoods
were of the same weight and at equal distances on each side of the contre X,
Over the hood E is fixed immoveably
they would balance one another.
another and larger vessel G, open at the bottom and sealed by water, having
a communication with the drum of the meter, or rather with the drum cover
at F. The action of these hoods, which I call regulating hoods, will be this:
-The pressure of the gas in the hoods E and H is, as before assumed, four
tenths, the pressure to work the drum of the meter, also assumed before, is one
tentl, the pressure of the gas in the fixed vessel G is therefore four tenths
minus one tenth, or three tenths, because it is in equilibrium with the interior
of the meter drum. I have already said that the measured gas is discharged
through the opening N with a pressure of three tenths also. Now the gas

page_text: in the hoods E and H being four tenths, and that in the vessel G being three
ienths, the equilibrium of the hoods is destroyed; and the hood H has a
descending power of one tenth, or of the. difference of the pressures existing
on the interior and exterior surfaces of the hood E. The openings M and N,
adjusted by the movement of the hood H, are, by its descent, partially closed,
and the pressure of the gas flowing through them is reduced by so much as
exists between the gas flowing into the meter drum through the pipe.B', or the
initial pressure, or that between the interior and exterior surfaces of the hood
E, videlicet, one tenth, so that the gas now flows through both openings, M
and N, with the same relative velocities, the discharges. being in proportion
to their areas. Supposing that the measuring drum required a pressure of
two tenths head of water to work it instead of one tenth, and that the initial
pressure was still four tenths, the pressure in the cover of the drum and in the
fixed hood G will then be two tenths. The gas will issue from the opening
N with a pressare also of two tenths, for the reason before explained, and the
differerences of pressure between the interior of the hoods E and II and the
exterior of the hood E being two tenths, the hood II will have a descending
power of two tenths, and thus in this instance also the velocities with which
the gas issues through M and N will be equalized, and so for any other
pressure.
I have herein-above described the openings through which the measured
and unmeasured gas issues, as regulated by means of a slide valve, but the
openings may be regulated by other means.
In the foregoing description the meter is supposed to be at work; but if,
through any accident or other cause, the measuring drum should cease to
revolve, the regulating hoods which equalize the flow of gas through the
openings M and N so act as entirely to shut off the gas from the burners.
The drum remaining stationary will prevent the entrance of more gas than
will fill one chamber, and the pressure in all the vessels will be the same.
Now the hood H is made heavier than the hood E, and being uninfluenced
by difference of pressure; will descend by its gravity and close the openings
M and N, and shut off the communication with the burners. The same
principle of measurement may be applied to dry meters, and I prefer to do so.
in the following manner:-The gas from the mains or services enters the
meter, and is divided immediately into two streams, as before described in the
water meter; one stream passes through the pipe A into the meter to be
measured, which measurement is to be effected by means of diaphragms or
contrivances in common use, and well known to those persons conversant with

page_text: dry meters. The other stream passes through the pipe B into the chamber C,
on which two small plates or diaphragms D and E are placed, connected
together by a lever or arin F. These small plates are secured to the top of
the chamber by loose rings of leather, or other elastic substance, in the same
way as the top and bottom boards of a common pair of bellows, and are free
to move to a certain extent up and down. The lever F vibrates upon a contro
G, so that when the diaphragm D rises the diaphragm E falls, and vice versa.
To the plate of the diaphragm E is attached a rod II, which works a slide
valve J, and opens or closes two openings K and L, precisely in the same
inanner as the two openings N and M in the before-described water meter are
opened or closed. Over the diaphragm D is a chamber or hood O, having a
communication with' the meter by means of the pipe P and with the small
opening L by means of the pipe Q, through which the measured gas unites
with the unmeasured or neutral gas, and passes to the burners. The
gas
discharged through the two openings K and L with the same pressure, or as
near thereto as may be, so that the areas of the two openings being known,
and the quantity of gas issuing through the small opening I being known, tho
total quantity issuing through both may be known also and registered. The
way in which the regulating diaphragms and apparatus connected therewith
equalize the pressure or velocity with which the gas issues from the openings
K and L is the same as in the before-described 'water meter, and by reference
thereto it can be understood.
is
Having thus described the nature of my Invention, and the means resorted
to by me for carrying the same into practice, I would have it understood that
I do not make any claim to the parts separately, nor do I confine myself to
the details herein described, so long as the peculiar mode of measurement be
retained; but what I claim as my Invention is, the dividing of the gas which
passes through a meter into two or more portions, and ascertaining the whole
quantity by measuring part thereof when under pressure, instead of measuring
all the gas which passes through the meter, as heretofore.
And also claim as iny Invention the making of the inner circle of the
drum of a water meter water-tight, that being in water it may be buoyant,
and prevent the weight of the said drum pressing upon the axis thereof.
In witness whereof, I, the said Samuel Clegg, have hereunto set my
hand and seal, this Twenty-sixth day of September, in the year of
our Lord One thousand eight hundred and forty-eight.
SAMUEL (L.s.) CLEGG.

page_text: AND BE IT REMEMBERED, that on the. Twenty-sixth day of Sep-
tember, in the, year. of our Lord 1848, the aforesaid Samuel Clegg came
before our said Lady the Queen in, Her Chancery, and acknowledged the
Specification aforesaid, and all and every thing therein contained and speci-
fied, in form above written. And also the Specification aforesaid was stainped
according to the tenor of the Statute made for that purpose.
Enrolled the Twentieth day of October, in the year of our Lord One
thousand eight hundred and forty-eight.