IN GAS METERS
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Samuel Johnson at the Office of the
Commissioners of Patents on the 14th December 1876.
"IMPROVEMENTS
SAMUEL JOHNSON, of Wood Green, in thic County of Middlesex.
IN GAS METERS."
"
This Invention relates to that form of meter used for the purpose of measuring
the quantity of gas passing through it which is known as a
wet" meter, and has
for its objects improved methods of constructing and arranging the parts of such
meters so that they are simpler, cheaper, and more effective than "wet" gas meters
as heretofore constructed and used.
I take a cylindrical drum or measuring vessel of sheet metal or other suitable
material, which is fixed upon a horizontal axis revolving in bearings formed upon
or attached to an outer case or box within which the measuring drum is contained.
The drum has a part of its circumference (preferably about one-fourth, or 90°) re-
moved, and the remaining part is divided into two equal chambers by a radial
internal division extending from the axis to the circumference. At the bottom of
the outer case I arrange two pipes (or one pipe divided into two by a longitudinal
division), which rise vertically into the interior of the measuring drum, passing
through the latter where its circumference is removed, and being bent or curved
laterally so as to escape the axis and rise to a sufficient height into one of the two
chambers into which the drum is divided. Two precisely similar pipes (or one pipe
divided into two by a longitudinal division) are arranged side by side with those
first described, and rise to the same height into the other of the two divisions into
which the drum is divided.
By the method of construction and arrangement described the drum cannot make
a complete revolution, but can oscillate backward and forward to an extent limited
by the extent of its circumference, which is removed as already described, and
through which the pipes pass. The upper ends of the two pipes (or the divided
pipe), which rise into each compartment of the drum, are provided with a slide
valve capable of a certain amount of lateral travel, and the size of each valve and
of the opening in the pipes which it covers are so proportioned that whilst only one
of the pipes can be opened at once each is opened alternately by moving the slide
valve backward and forward. I arrange a horizontal sliding bar having teeth or
lugs upon its edge, which are actuated by a toothed wheel or segment or lever
fixed to the axis of the drum, so that when the latter is made to oscillate back-
[Price 2d.]

page_text: ward and forward as already described, the sliding bar is also made to slide or
travel simultaneously backward and forward; and at or near each end of the
sliding bar I arrange bars, pins, or levers, which strike or actuate the slide valves,
and drive them backward and forward. I arrange the pins, bars, or levers, so that
they only actuate the slide valves at the extreme ends of the stroke of the
sliding bar (and of the oscillating drum), and I attach upon the upper part of the
drum, or upon a lever on its axis, an adjustable weight which aids the movement of
the drum and of the sliding bar at the ends of their stroke. I connect one of each
of the pipes (or one division of cach divided pipe), after it leaves the drum case,
with an inlet gas pipe, and the other of cach of the pipes (or the other division
of each divided pipe), with an outlet gas pipe, and I fill the drum case and drum
with water.
The proper level of the water may be regulated by any of the methods well
known and practised for the purpose in "wet" gas meters; but I prefer to adjust
and maintain it by the following novel arrangements. I make an external chamber
in communication with the drum case of the meter, so that the water stands at the
same level in each; the bottom of this chamber is provided with a hollow screwed
socket, into which is screwed a vertical pipe; the hollow socket outside the chamber
is provided with a moveable watertight cap; the upper end of the vertical pipe is
provided with a hole, square or of other suitable shape, to fit a key which is intro-
duced through an opening in the top of the external chamber; by this means the
pipe can be screwed up or down until its upper edge exactly coincides with the
level of the water in the meter when the latter is indicating correctly, and any
surplus water passes down the pipe and can be removed by means of the moveable
cap when required. When the pipe has been adjusted to its proper height the
opening in the top of the external chamber is closed by a plate or screw cap, which
may be sealed so that it cannot be interfered with. I arrange an adjustable valve,
actuated by a float upon the surface of the water, and adjusted in such manner
that if the level of the water falls too low the valve closes the inlet pipe and so
shuts off the supply of gas from the meter until the proper level of the water has
been restored by the addition of a fresh supply, which may be supplied by any of
the methods ordinarily used and practised.
I sometimes provide an external cistern or reservoir, and I arrange in connection
with it a float valve which admits water into the meter if the level of the water in
the latter should fall too low.
The pipes and slide valves described are arranged so that when the drum is at
one end of its oscillation the inlet pipe into the chamber which is lowest is un-
covered by its valve whilst the outlet pipe is closed; and in the other chamber,
which is highest, the outlet pipe is opened by its valve, and the inlet pipe is closed;
at the other end of the oscillation the contrary is the case.
By the novel method of construction and arrangement described the measuring
druin is made to oscillate backward and forward continuously by the pressure of the
gas so long as the latter is admitted through the gas inlet pipe and allowed to pass
away through the outlet pipe, the position of the valves being reversed at each
end of each oscillation, the direction of which is accordingly reversed at the
same time.
Indicating apparatus of the kind ordinarily used may be attached to the
drum case, being operated by a pall or lever attached to the axis of the drum
and actuating a ratchet wheel connected to or forming part of the indicating
apparatus.