IMPROVEMENTS IN GAS METERS
Year: 1839

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HEMMING, of Edward Street, Cavendish Square, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Sixteenth day of July, in the third year of Her 'reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said John
Hemming, Her especial license, full power, sole privilege and authority, that
I, the said John Hemming, my exors, adiñors, and assigns, or such others
as I, the said John Hemming, my exors, admňors, 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 John Hemming, shall
cause a particular description of the nature of my said Invention, and in what
manner the same is to be performed, to be inrolled in Her said 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
John Hemming, do hereby declare the nature of my said Invention, and the
manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had to.

page_text: the Drawing hereunto annexed, and to the figures and letters marked
thereon (that is to say):-
The meters, with few exceptions, employed for measuring and registering the
quantity of gas delivered for consumption contain water or other liquid, which
should always be at a certain level within the meter, otherwise the register
will indicate a quantity greater or less than has actually passed through, in
proportion as the quantity of liquid in the meter is greater or less than it
ought to be. In addition to this evil it sometimes occurs that the water in
the meter becomes frozen and it will not then act. My improvements in
gas meters consist in the employment of a mode hereafter described for
maintaining the liquid at an uniform height in the meter, and also of the use
of a liquid or liquids not liable to freeze at the freezing point of water, and
lastly, in protecting the brass or other metallic parts of the meter from
corrosion by the voltaic or chemical action which is so frequently destructive
thereto.
To maintain the liquid at an uniform height within the meter, I superadd
to an ordinary gas meter what I call a supplementary cistern, as represented
in the Drawing annexed, and marked A and B. This is divided into two
portions, the lower of which communicates by two pipes C and D with
the meter. The upper pipe is attached to the aperture, over which the liquid
should flow when the meter is sufficiently full. The upper portion of the
cistern is provided with an aperture, which may be closed perfectly air-tight
with a screw and leather washer of the usual kind. There is a tube of glass
or metal fixed in the upper portion of the cistern, which passes through an
aperture made air-tight by means of solder or cement, or by passing through
a pierced cork inserted tightly into the aperture, and terminates as little
below the proper level of the liquid as possible (see E in the Drawing.) The
lower cistern is provided with a pipe of glass or metal, curved and recurved,
the lower end of which passes through the bottom of the cistern, while the
upper end terminates or opens at the line where the proper level of the liquid
ought to be (see F).
.
In filling the meter with liquid in the usual way, it will enter the lower
part of the supplementary cistern and stand at the same level therein as in
the meter until it rises above the level of the pipe F, when the excess will be
discharged through the pipe. The screws previously removed to fill the meter
may now be fastened and the liquid remaining in the bent pipe will prevent
the admission of air to the cistern or meter. The upper part of the cistern
is now to be filled with liquor, the aperture in the tube being closed during
the operation by a plug of conical form; I employ for this purpose the

page_text: handle of a common paint brush.
fastened to prevent waste of liquid.
proper quantity of liquid, a farther
which is sometimes the case, it will rise above the aperture of the pipe F,
and the superfluous quantity will be spontaneously discharged. If there be
any loss of liquor in the meter arising from evaporation or from other causes,
the level will fall below the aperture of the tube E, by which air or gas will
pass through it, and a corresponding volume of liquid will fall from the upper
portion of the cistern A to the lower B, and thus the level of the liquor will
be unformly preserved so long as there is liquor in the upper part of the
cistern A.
The screw must then be immediately
If, after the meter is charged with the
and unnecessary portion should enter,
To prevent loss by evaporation or freezing of liquor during cold weather,
I employ a weak solution of chloride of calcium or muriate of lime, which is
not so liable to evaporation as water, and which does not freeze until cooled
considerably below the freezing point of water. Or, I place in the meter
and lower portion of the cistern a weak solution of common salt, and as only
the aqueous portions of this will evaporate, I fill the upper part of the cistern
with fair water only. In order to protect the metals in the meter liable to
corrosion by voltaic or chemical action, I attach by solder or rivetting pieces
of zinc to those parts most likely to be affected, it being well known that
zinc protects other metals less oxidable than itself from chemical action when
exposed to fluids which cause chemical action.
Having thus described the nature of my Invention, I would have it under-
stood that what I claim as my Invention is,―
First, the mode herein described of maintaining an uniform level of fluid
in gas meters, as herein described.
Secondly, I claim the combining of a fluid not liable to be acted on by the
cold (to which gas meters are liable) with such apparatus for maintaining the
uniform level of fluid in the meter, as above described.
Thirdly, I claim the application of a weak solution of chloride of calcium
or muriate of lime in gas meters to prevent the prejudicial effects of frost, as
above described.
And lastly, I claim the application of zinc to protect the brass or other
metal parts of meters liable to corrosion, as above described.
In witness whereof, I, the said John Hemming, have hereunto set my
hand and seal, this Sixteenth day of January, in the year of our
Lord One thousand eight hundred and forty.
JOHN (L.B.) HEMMING.

page_text: AND BE IT REMEMBERED, that on the Sixteenth day of January,
in the year of our Lord 1840, the aforesaid John Hemming came before our
said Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that
purpose.
Inrolled the Sixteenth day of January, in the year of our Lord One
thousand eight hundred and forty.