IMPROVEMENTS IN DRY GAS METERS
Year: 1876

page_text: LETTERS PATENT to William Smith, of Kennington, in the County of Surrey,
Gas Meter Manufacturer, for the Invention of "IMPROVEMENTS IN DRY GAS
METERS."
Sealed the 23rd June 1876, and dated the 6th March 1876.
PROVISIONAL SPECIFICATION left by the said William Smith at the Office
of the Commissioners of Patents on the 6th March 1876.
WILLIAM SMITH, of Kennington, in the County of Surrey, Gas Meter Manu-
facturer. "IMPROVEMENTS IN DRY GAS METERS."
The usual mode of constructing the "diaphragm" in dry gas meters is to make
both rims of the same size, to fasten the leather to both, and in the working to cause
the two rims to all but touch each other when expelling the gas from the interior
of the diaphragm. Now according to the first part of my Invention, I make the
upper rim of the diaphragm somewhat larger than the lower one, which latter I
make of about the ordinary size, and I also shape the leather preferably so that
it has the bulge nearer the upper rim. I make the rims in working preferably to
approach one another, so that the bottom of the upper rim does not pass below the
top of the lower rim. I thus obtain a diaphragm which can register considerably
larger volumes than the ordinary ones, and the action of which is better, the friction
lessened, and I use less leather.
In the Specification of a provious Patent of mine, dated 15 May 1868, No. 1600,
I have described a diaphragm in which the rims are of different size, but according
to this present Invention I arrange them in a directly opposite manner to that
described in the Specification of the Patent before referred to, that is, I make the
large rim the movable one, and the small rim the fixed, whereby I obtain much
better results than heretofore, registering more gas, and very materially reducing
the friction.
My Invention further consists in making diaphragm rims with projecting flanges
of, say a double U or other convenient shape, by which means I obtain a bearing to
receive the disc, which is soldered thereon by this means, the disc is soldered on to
the rim without the soldering affecting the leather, which often results when the
diaphragm rims are made in the ordinary way.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said William Smith in the Great Seal Patent Office on the 6th September
1876.
WILLIAM SMITH, of Kennington, in the County of Surrey, Gas Meter Manu-
facturer. "IMPROVEMENTS IN DRY GAS METERS."
The usual mode of constructing the "diaphragm" in dry gas meters is to make
both rims of the same size, to fasten the leather to both, and in the working to
cause the two rims to all but touch each other when expelling the gas from the
interior of the diaphragm. Now according to the first part of my Invention, I make
the upper rim of the diaphragm somewhat larger than the lower one, which latter
I make of about the ordinary size, and I also shape the leather preferably so that
it has the bulge nearer the upper rim. I make the rims in working preferably to
approach one another so that the bottom of the upper rim may pass below the top
of the lower rim if necessary. I thus obtain a diaphragm which can register
considerably larger volumes than the ordinary ones, and the action of which is
better, the friction is lessened, and I use less leather.
Figure 1 of the accompanying Drawings is a front elevation with part of the front
side or wall removed of a dry gas meter fitted with my improvements. Figures 2
and 3 are side elevations partly in section; Figure 2 showing the front diaphragm
collapsed, and the back diaphragın extended, and Figure 3 showing the diaphragms
in the reverse positions. Figure 4 is an enlarged part section, showing the
construction of my improved upper diaphragın rim.
C,
a and a¹ are the upper diaphragm rims, and b, b', the corresponding lower dia-
phragm rims, the former being somewhat larger in diameter than the latter, and
these latter being of about the ordinary size. The bulge of the leather c, c', is here
shown nearer the upper rims a, a, and the bottom edge of the latter as just above
the top edge of the lower rims b, b¹. I prefer to arrange and cut the leather c¹,
so that there are three or more seams in the circumference, which seams extend in
a straight line from one rim a, a, to the other b, b1, by this means the leather
is hardly strained at all, no puckering or folding takes place at the smaller rim b, b¹,
and a perfectly even and easy action is obtained, the friction being less than hereto-
fore, and the quantity of leather required being also reduced.
In the Specification of a previous Patent of mine, dated 15 May 1868, No. 1000,
I have described a diaphragm in which the rims are of different size, but according
to this present Invention I arrange them in a directly opposite manner to that
described in the Specification of the Patent before referred to, that is, I make the
large rim the movable one, and the small rim the fixed one, whereby I obtain
much better results, and larger capacity than can be obtained in meters of ordinary
construction.
My Invention further consists in making diaphragm rims with projecting flanges
of say a double U or other convenient shape, by which means I obtain a bearing to
receive the disc, which is soldered thereon, by this means the disc is soldered on to
the rim without the soldering affecting the leather, which often results when the
diaphragm rims are made in the ordinary way.
This part of my Invention will be most clearly seen at Figure 4. The rim a is
here formed with a projecting flange of a shape as shown at a, the face part e of
the rim is thus so far from the place where the leather c is fastened on that the
disc can be soldered on without unduly heating the leather.
And having thus fully described the nature of this Invention, I declare that I
claim as applied to dry gas meters-
First. Making the upper or movable rims a, a¹, of a somewhat larger diameter
than the lower or fixed rims b, 61, as and for the purposes set forth.
Second. Forming the upper rims a, a¹, with a bent over flange for attaching the
disc thereto, as and for the purpose set forth.

page_text: Third. The formation of the diaphragm leather as set forth.
In witness whereof, I, the said William Smith, have hereunto set my hand
and seal, this Sixth day of September, in the year of our Lord One thousand
eight hundred and seventy-six.
*. SMITH.
(L.S.)