IMPROVEMENTS IN DRY GAS METERS
Year: 1875

page_text: LETTERS PATENT to Edward Ellice Crombic, of the Metropolitan
Works, Diana Place, Euston Road, in the County of Middlesex, for
Sealed the 27th April 1875, and dated the 4th February 1875.
-PROVISIONAL SPECIFICATION left by the said Edward Ellice Crombie.
at the Office of the Commissioners of Patents, with his Petition,
on the 4th February 1875.
I, EDWARD ELLICE CROMBIE, of the Metropolitan Works, Diana
5 Place, Euston Road, in the County of Middlesex, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN DRY GAS METERS," to
be as follows:-
The object of this Invention is to reduce the friction of dry gas meters.
to a minimum, and to do away with the intricate gas passages under the
valve plate, at same time increasing the capability of working at a lower
pressure than hitherto, and the obtaining a larger and steadier flow of
gas through it than from any other meter in existence of an equal
size..

page_text: This meter I construct in the following manner :-The lower part of
the meter is as usual divided by a vertical partition into two separate
measuring compartments, within each of which is contained a flexible
bag or diaphragm carried by the central partition. At the top of the
meter is a horizontal closed compartment into which the gas passes
from the measuring compartment before it passes to the burners.
Within this horizontal compartment is a small chamber into which gas
is constantly admitted by the inlet pipe. Upon the top of this chamber
rests two valves which may be termed irregular oblongs. Each valvo is
arranged to pivot upon a pin at one end, and its opposite end works over
two ports, one passing to the interior of one of the diaphragms and the
other to the chamber in which the diaphragm is contained. Gas passes
at all times into the interior of the valves through a port near to that
end upon which the valve pivots while the outer end of the valve is
caused alternately to cover over first one and then the other of the two
ports leading to the inside and outside of diaphragms respectively.
When it covers the port leading to the diaphragm gas is supplied to the
interior of the diaphragm whilst the port leading from the exterior
chamber remains uncovered, permitting gas to pass freely from it to the
upper chamber of the meter and thence to the burners. When the
valve covers the port leading to the chamber containing the diaphragm

page_text: a great amount of friction is obviated and the liability of leakage at
stuffing box immensely reduced, the index itself being encased in a
gas-tight box.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Edward Ellice Crombic in the Great Seal Patent,
Office on the 4th August 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
ELLICE CROMBIE, of the Metropolitan Works, Diana Place, Euston Road,
in the County of Middlesex, send greeting.
our
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourth day of February, in the year
of 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 Edward Ellice Crombic, Her special license
that I, the said Edward Ellice Crombic, my executors, administrators,
and assigns, or such others as I, the said Edward Ellice Crombie, my
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, usc, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN DRY GAS METERS," upon the condition (amongst others) that I, the said
Edward Ellice Crombie, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said In-
vention, 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 calender
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Edward Ellice Crombie, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say:
The object of this Invention is to reduce the friction of dry gas meters

page_text: to a minimum, and to do away with the intricate gas passages under the
valve plate, at same time giving the capability of working at a lower
pressure than hitherto, and obtaining a larger and steadier flow of gas
throughout than from any other meter in existence of an equal size.
This meter I construct in the following manner:-The lower part of
the meter is as usual divided by a vertical partition into two separate
measuring compartments, within each of which is contained a flexible
bag or diaphragm carried by the central partition. At the top of the
meter is a horizontal closed compartment into which the gas passes
from the measuring compartment before it passes to the burners.
Within this horizontal compartment are two valves which may be
termed irregular oblongs. Each valve is arranged to pivot upon a pin
at one end, and its opposite end works over two ports, one passing to the
interior of one of the diaphragms, and the other to the chamber in
which the diaphragm is contained. Gas passes at all times into the
interior of the valves through a port near to that end upon which the
valve pivots, while the outer end of the valve is caused alternately to
cover over first one and then the other of the two ports leading to the
inside and outside of the diaphragms respectively. When it covers the
port leading to the diaphragm gas is supplied to the interior of the
diaphragm, whilst the port leading from the exterior chamber remains
uncovered, permitting gas to pass freely from it to the upper chamber
of the meter and thence to the burners. When the valve covers the
port leading to the chamber containing the diaphragm the action is
reversed.
The two pivotted valves both receive motion from a shaft contained
within the upper chamber, and this shaft receives a revolving motion
from the alternate collapsing and expanding of the measuring diaphragms
in the ordinary well-known manner.
All the intricate passages or gas ways under the valve plate are done
away with completely, there being only a simple passage leading from
the inner port hole of each valve to the inside of each diaphragm, thus
doing away with the stoppage of the flow of gas caused by the many
sharp turns in the passages now in use. The friction of this meter is
reduced by having each valve working on a pivot at the round end and
placed close to the cover, thus dispensing with nearly one half the
usual pressure to move it. This combined with the fact that the

page_text: stuffing box is placed on the spindle connecting the index and not on the
crank as in other meters, the crank making many revolutions for one of
the spindle (in some cases more than 20 times), it will thus be seen that
a great amount of friction is obviated and the liability of leakage at
stuffing box immensly reduced. The index itself being encased in a
gas-tight box.
Figure 1 shows a plan view of the meter with the top of the outer
casing removed, and Figure 2 shows a back view with the back of the
casing removed.
In these Figures A is the outer casing, B a horizontal partition placed
across the casing. Below this partition the meter is divided as usual by
a vertical partition into two separate measuring compartments, within
each of which is a flexible cylindrical bag C secured at one end to a ring
which projects out from the vertical partition, and at the other end
secured to a disc, D. Projections from the centre of this disc are jointed
to an arm E on a vertical spindle F, which is carried up through a
stuffing box G on the horizontal partition B, and above the partition
carries an arm H coupled by a link to a crank on a vertical axis.K, in
order that a revolving motion may be given to this vertical axis by the
alternate collapsing and expanding of the flexible bags in the ordinary
manner. On the vertical axis K is a crank K' which by links L gives
motion to the valves M, as shewn in the plan view, Figure 1. An under
side view and longitudinal section of one of the valves are shown at
Figures 3 and 4.
A plan view of one of the valve faces is shown separately at Figure 5.
In this valve face are three ports, the central port is by a passage N con-
nected directly with the inlet pipe O, as shown in the vertical section
Figure 6, which is taken through the centre of the valve face and
through the inlet pipe. From each of the inner ports a passage P
passes directly to the ring which stands out from the vertical partition
of the meter and to which the flexible bag is connected, and thus a
passage is formed from the port into the interior of the bag. Below

page_text: cach of the outer ports is an opening in the horizontal partition B, so
forming a passage into the chamber in which the flexible bag is con-
tained. Each valve simply rests upon one of the valve faces and turns
on a pin Q at one end, whilst at the opposite end it is coupled by the
link L to the crank on the axis K as before explained, so that as the
axis is revolved the two outer ports of cach valve face are alternately
covered and uncovered by the valves, as before explained, so as alter-
nately to supply gas to and allow it to escape from both the flexible
bags and the chambers in which the bags are contained. R is a wire
to prevent the valves from getting out of place when the meters are
carried about; S is a tumbler carried by an arm on the axis K. This
tumbler allows the axis to turn freely in one direction, but prevents any
movement of the axis in the contrary direction. T is a worm on the
axis K; this gives motion to a worm wheel U on an axis V. This axis
passes through a stuffing box at W into a gas-tight casing X containing
the counting apparatus and index for recording the amount of gas passed
through the meter. Y is the outlet pipe into which gas passes from
the chamber at the upper part of the meter through an opening at Y'.
By the arrangement of passages and valves herein-before explained
not only is the construction of the meter simplified, but the friction
attendant on working it is reduced. The friction is also still further
reduced by forming the whole of the upper part of the meter into a gas
chamber containing the axis K and parts in connection therewith, so
that in place of the axis K being passed through a stuffing box as
heretofore usual, a stuffing box is placed upon the axis V of the
recording apparatus which revolves at a much less speed than tho
axis K.

page_text: motion to such axis, substantially as and for the purpose herein-before
described.
In witness whereof, I, the said Edward Ellice Crombie, have here-
unto set my hand and scal, this Thirty-first day of July in
the year of our Lord One thousand eight hundred and seventy-
five.
EDWARD ELLICE CROMBIE. (L.s.)