Improvements in Gas Meters.
Year: 1890

page_text: Date of Application, 8th Apr., 1890-Accepted, 17th May, 1890
COMPLETE SPECIFICATION.
Improvements in Gas Meters.
We ROBERT MITCHELL Manufacturer and CHARLES LAWSON, Meter Maker both
of the City of Montreal in the District of Montreal and Province of Quebec Dominion
of Canada do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
This invention comprises certain improvements in the construction of gas meters
and has for its object to produce a meter which will register with accuracy up to a
higher pressure than can be done by any now in use; its working parts being more
durable and more easily cleaned replaced and put in order when needed.
This capacity of registering to a higher pressure is attained by forming the ports
through which the gas passes to and from the diaphragm respectively from and to the
inlet and outlet pipes of a sectional area considerably less than that of each of the
pipes themselves, the opening in the diaphragm through which the gas is delivered
and discharged being equal in sectional area to that of both the inlet and outlet ports
plus a small additional area for freedom of passage.
To obviate the difficulties inherent in the present construction of a meter in which
the diaphragm is a fixture and which renders cleaning and repairing very difficult and
troublesome. we propose to make the diaphragm entirely separate from the division
securing it thereto preferably by means of lugs formed on the back plate through
which pass threaded pins from the division; nuts screwed upon them securing them
in place.
To allow of the removal of the diaphragm we make the sockets, through which the
ends of the motion wire pass, horizontal, the wires themselves being straight the
whole of their length.
The end pin of the centre passes through eyes in arms projecting from the front of
the diaphragm a screwed bush on the top holding it in place so that it can be drawn
down and out after the attaching devices are removed.
In order to do away with the defects of the present method of securing the bellows
or expansible sides to the front and back platos whereby the leather is scorched and
hardened by the heat due to soldering on to the plates of the retaining beads, we
propose to spin or turn up on the rim of the plates a flange composed of a double
bead with a groove between, in which is laid the edge of the leather. This is held in
place by wire or metal bands passed round over it, one end being secured by solder
to the turned up edge of each plate.
In order to allow of access to the inside of the diaphragm for the purpose of
cleaning we cut out originally from the back plate a large concentric opening and
cover this with a plate secured thereon by any suitable means. This is taken off when
the diaphragm is taken out of the meter, thereby allowing free access to the interior
of the diaphragm and enabling an unskilled operator to do all that is necessary even
to renewing the leathers, which, being put in place on a block in the usual way, are
secured to both plates simply by laying their edges in the grooves and winding the
wire or band round them."
We further propose to make the valves controlling the influx of the gas into the
diaphragm with the grating or valve seat, separate from the valve plate, so as to allow
of their being easily removed for the purpose of being cleaned or for other purpose
allowing them to be accurately trued up to compensate for wear.
This section may with the first section of the pipes, be of incorrodible metal cast in
one-piece.
For full comprehension of the Invention reference is made to the annexed drawings
forming part of this Specification in which Figure 1 is a view of a meter with the

page_text: front plate broken away shewing the diaphragm and connections: Figure 2 is a back
view of the diaphragm: Figure 3 is a side view of same: Figure 4 is a top view
of the valve plate. Figure 5 is a horizontal sectional view on line x, x,
looking upwards and Figure 6 is a section through the diaphragm.
Similar letters of reference indicate like parts.
Figure 1
In these drawings the well known parts of a gas meter in which no change is
made and which are not necessary to illustrate our Invention are not shewn.
A is the frame of the meter and B and C respectively the inlet and outlet pipes b
and c being respectively the openings between these and the inlets into and exhaust
from the diaphragm.
These parts b and c are, as will be seen of comparatively small sectional area com-
pared to that of the pipes B and C, and, although it is impossible to give an absolutely
definite rule for the relative proportion of the pipes and ports in each of the different
sizes of meters, it has been found that in a two light meter, i.e. one passing twelve
feet of gas per hour, in which the pipes are half an inch in diameter, ports of three
sixteenths of an inch have been found to answer very well.
In meters of larger capacity the proportion of the area of the ports will be somewhat
increased but the openings into the diaphragm will always preserve the same
proportion, i.e. that each will be equal to the area of both the ports, plus a small
addition.
By this means the pressure of the gas in the diaphragm
is rendered even, whatever
may be the initial force, and it may be raised successively to double the height now
attempted with meters as hitherto constructed.
.
E is the diaphragm, F being the front plate, G the back one and H the expansible
leather.
On the side of each of the plates we spin or turn up a flange composed of a double
bead f. fg, g with grooves f g between them. In these grooves f g are laid the
edges of the leather which are secured in place by lengths of wire K, K₁, having one
end soldered to the turned up edges of the plates F. G. (usually before the leather is
laid on). and wound round over the leather holding it firmly in place in the
grooves 93 and making a perfectly tight joint, the other ends of the wire being
secured in any suitable way.
By this means all necessity for the application of heat to secure the leather and
plates together is done away with and all chance of burning or hardening the leather
so as to cause it to crack in use is obviated.
Instead of the wires K. K¹ a length or lengths of thin strips may be used and
secured in any desired way.
Upon the back plate G are formed any desired number of lugs G¹ G¹ through
which pass screwed pins 11 projecting from the division D; threaded nuts ll¹ screwed
on them holding the diaphragm to the division D.
In this back plate is cut, (as shewn in dotted lines in Figure 3) a concentric
aperture and this is closed as shewn in Figure 6 by a plate G which may be soldered
in place or secured to G by projections and pins or in any other suitable way (should
it be thought best to avoid the use of beat) such for instance as three or more bayonet
checks with a wedge-shaped indentation to tighten it up, and putty joints.
This plate G³, when the diaphragmn is taken out of the frame, is easily removed,
giving access to the interior of the diaphragm without the necessity of taking apart
the plates and leather, thus enabling an unskilled workman to do all that is required
for cleaning the diaphragm.
The mechanism in connection with the front plate F is somewhat modifiod to allow
of the withdrawal of tho diaphragm from the meter.
The ends M¹ of the motion wire M are vertical throughout their length and pass
through eyes m. m projecting from F and set horizontally.
The centre N is mounted on the vertical rod N' as usual, and is so arranged that the
eyes O. O formed in arms projecting horizontally in a vertical line from the front
plate F. can be disengaged from the ends of the outer pin n. Into the eye O is
screwed the bush P.

page_text: When the threaded nuts 1, 1, are unscrewed from the pins l. 1, the diaphragm E is
detached from the division D and by unscrewing the bush P the diaphragm is free to
be taken out as the eyes O can be disengaged from the pin n and the eyes m. m
from the wires M M the pipe being disconnected as will be presently described.
To replace the diaphragm in position after the cleaning or repairing has been
effected all that is needed is to exactly reverse the operation just described, finally
securing the lugs G¹ G', to the division I).
In Figures 1, 4 and 5 is shown as far as is required for illustrating the present
invention, the arrangement of the parts for effecting and regulating the influx and
efflux of the gas.
Qis the valve plate to which are secured separate plates Q1, Q¹, carrying the
gratings and valves governing the supply of gas to the diaphragm which are of the
usual type. R is the inlet taken from the inlet pipe B to the top chamber S, T is
the pipe from this chamber to the diaphragm the upper part of which may be made
in one with the plate Q, and the lower T', that connected with the diaphragm, being
a slip joint, the flange of the diaphragm, at the point of junction of this pipe may be
flattened out to receive it.
U is the exhaust taken to the outlet pipe. C.
In removing the diaphragm the slip joint T¹ is simply disengaged from the pipe T
as it is lowered.
Having now particularly described and ascertained the nature of the said Invention
and in what manner the same is to be performed we declare that what we claim is :-
1. In a gas meter, the diaphragm normally separate from the frame, and fastening
devices by which it can be attached to the meter frame, as hereinbefore set forth.
2. In a gas meter, the diaphragm composed of the front plate, expansible leather
sides, and hack plate with apertures therein, and plate normally covering the same,
as and for the purposes hereinbefore set forth.
3. In a gas meter, the diaphragm composed of front and back plates, each provided
with return flanges; leather sides with edges laid on such flanges, and lengths of wire
or metal wound round over such leather, as and for the purposes hereinbefore
described.
4. The combination with the front plate F of the diaphragm, of the centre N with
outer pin n, eyes 0. 0¹, and bush P as and for the purposes herein before set forth.
5. The combination with the valve plate Q with openings therein, of plates Q1
covering such openings attached to valve plate, so as to be removable at will, and
carrying valves and gratings.
6. In a gas meter, ports from inlet pipe to supply and from exhaust into outlet pipe,
of proportionately less sectional area than such pipes as and for the purposes
herein before set forth.
Dated this 8th day of April 1890.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, Agents.