Improvements in or connected with Fluid Meters.
Year: 1898

page_text: Date of Application, 4th Jan., 1898-Accepted, 26th Feb., 1898
[Communicated from abroad by THE PITTSBURGH SUPPLY COMPANY LIMITED, of
Pittsburgh, in the State of Pennsylvania, one of the United States of America.]
Improvements in or connected with Fluid Meters.
I, WILLIAM BURGELAND JOHNSON, of 4, Clayton Square, Liverpool, in the County
of Lancaster, Engineer, 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:--reference being had to the accom-
panying drawings:
-
Figure 1 is a horizontal sectional view, partly in elevation, showing one form of
my proportional meter. Figure 2 is a side elevation of the same; and Figures 3, 4
and 5 are views similar to Figure 1, showing other forms of my apparatus.
My invention relates to the proportional meters which are employed for determining
the volume of fluid passing through a conduit or main, wherein a portion of the
fluid is passed through a tally-meter, and it is designed to cheapen and simplify the
construction of such meters as well as to make them more accurate in measurements,
than has heretofore been possible. To that end it consists in a proportional
meter, having oppositely acting pressure-plates, arranged to control by their balance
It also consists
the valves for the measured and unmeasured volumes of the fluid.
in a valve controlling a direct inlet to the delivery chamber of the meter, a
pressure-plate acted upon by the unmeasured fluid entering the delivery-chamber,
which pressure-plate may be constituted by the inlet valve itself, and a second
pressure-plate acted upon by the measured gas passing from the tally-meter, the
It also consists in the last-named
two pressure-plates controlling the inlet valve.
combination, wherein the meter-delivery valve, as well as the direct inlet valve is
controlled by the pressure plates. It further consists in the construction and
arrangement of the parts as hereinafter more fully described and set forth in the
claims.
In the drawings, referring to Figures 1 and 2 in which I show a simple form of
my apparatus, 2 represents the casing of the proportional meter proper, and 3 the
fluid inlet therefor. The direct delivery-chamber 4 in the meter is separated from
the inlet by a partitition 5, having a central inlet-opening controlled by the direct
inlet-valve 6. This valve is mounted on a stem 7, which slides longitudinally in
guides 8 and 9 within the meter, and moves in the direction of the fluid current to
close the inlet-opening.
To the end of the rod 7 is secured a diaphragm 10, preferably consisting of
the usual centre-plate having a flexible annulus which is secured in the casing.
From the
11 is a tally-meter which is connected to the inlet 3 by the pipe 12.
tally-meter, the fluid which has been measured therein, passes through pipes 12
into a valve-chamber 13. This valve-chamber 13 communicates with the delivery-
chamber 4 of the meter by an opening which is controlled by a valve 14 mounted
upon a stem 15 which at one end is pivotally connected to a bell-crank 16. The
bell-crank lever is provided with a forked-end portion engaging a pin 17 upon the

page_text: valve rod 7 which controls the movements of the meter delivery valve 14.
From the pipe 12, a branch pipe 18 leads into the diaphragm-chamber 19 formed
by the diaphragm 10.
The area of the opening for the meter delivery valve is made such that its ratio to
the area of the opening of the direct inlet valve, shall be equal to the ratio of the
determined capacity of the tally meter to the volume of fluid passing to the direct
delivery, so that under all degrees of opening of the direct delivery-valve and the meter
delivery valve, the proportionate delivery of the meter is constantly equal to the
predetermined fraction of the supply volume with which the capacity of the
tally-meter accords. The effective area of the diaphragm 10, which constitutes
what I term a low pressure-plate, is greater than the effective area of the inlet-valve 6,
which, in this form, is in itself both a valve and what I term the high-pressure-plate.
The operation is as follows: The fluid entering at 3, passes through pipe 12 to
the tally-meter, and having passed through this meter flows through pipe 18 to the
diaphragm-chamber 19, until sufficient pressure has accumulated therein to actuate
the rod 7, so as to move the valve 6 into an open position, this rod at the same
time opening the meter delivery valve 14. The fluid then passes through the direct
admission valve into the delivery-chamber 4, and also, by way of the tally-meter,
pipe 12 and meter delivery valve 14, to the same chamber 4, from which the fluid
passes through the outlet 20. To maintain the required proportion of flow of fluid
through the direct admission valve 6 and the meter delivery valve 14, it is necessary
that there shall be a constant ratio of drop through the direct admission-valve and
the meter-delivery-valve. This ratio of drop or reduction in pressure is obtained
and maintained by means of the high pressure-plate constituted by the valve 6
itself, which is opposed by the low pressure-plate 10 of greater area, which is acted
upon by fluid of a less pressure, namely, that which is passed through the tally-meter.
These two pressure-plates acting in opposite to each other, force the valve 6 to a
position where equilibrium is established between the pressures acting upon the
pressure-plates.
If the amount of the absorption of pressure by the tally-meter varies, it is evident
that a corresponding variation of pressure will occur in the diaphragın-chamber 19,
thus changing the position of the direct inlet and meter delivery valves to correspond
thereto. The friction of the tally-meter therefore is not allowed to affect the ratio
of the volume of fluid passing through the proportional valves, and changes in the
pressure of the fluid will not change the ratio between the volume of gas passing
through the direct inlet-valve and that passing through the tally-meter and its
delivery-valve.
Thus for instance, if in a meter of this type the effective area of the high
pressure-plate is one-half the effective area of the low pressure-plate, as these two
plates act in opposition to each other, it will require one-half as much pressure acting
on the low pressure-plate as that acting on the high pressure-plate to counteract the
pressure on the latter plate, and force it and the proportional valves to take up such
a position that the supply volume may pass, equilibrium being established between
the pressures acting on the two pressure plates. The difference in the pressures
acting on these two plates is, of course, due to the absorption of pressure by the
tally-meter. If the absorption of the tally-meter is equal to one inch water column,
then the difference in the pressures acting on the two pressure-plates, and the
pressure acting on the high pressure-plate, will be two inches, and the pressure on
the low pressure-plate, one inch. In this case the drop through the direct inlet-valve
will be two inches and the drop through the meter delivery valve one inch, and if the
relative area of opening of the small valve to that of the large valve is 1 per cent.,
the flow through these valves being in proportion to their area and the square root
of the drop through them, the volume per square inch of area passing through the
direct inlet would be 1414 times the volume per square inch of area passing through
the meter-delivery valve, since the square root of two equals 1.414 and the square root
of 1 equals 1.
If the absorption of the tally-meter should increase to say two inches water

page_text: column, the delivery of volume remaining the same, the pressure on the low
pressure-plate or diaphragm 10 would be reduced, and the pressure acting on the
high pressure-plate would remain the same. The proportional valves would be then
forced to a more nearly closed position, until the pressure accumulated and
equilibrium was again established, and the pressure acting on the high pressure-plate
will be equal to 4 inches, and that on the low pressure-plate equal to 2 inches. In
this case the drop through the direct inlet-valve is 4 inches and the drop through
the meter delivery-valve 2 inches. The square root of 4 being equal to 2, and the
square root of 2 being equal to 1.414, 2 divided by 1.414 equals 1414, the same
ratio as before.
If the effective area of the high pressure-plate be equal to one-quarter the effective
area of the low pressure plate, it will take one-quarter as much pressure upon the
low pressure-plate to counteract that on the high pressure-plate and give equilibrium.
In this case, if the absorption of the tally-meter is equal to 1 inch water column,
then the difference in the pressures acting on the high and low pressure plates will
be 1 inch, and the pressure acting on the high pressure-plate will be 1.333, and the
pressure acting on the low pressure-plate will be 333, or one-quarter the pressure on
the high pressure-plate. The square root of 1.333 is equal to 1-154; the square root
of 333 is equal to 577. Dividing 1.154 by 577 we find the relative flow through
the valves is equal to 2, that is one-half as much gas passes through the small valve
per square inch of area as through the direct inlet-valve. If, now, the absorption of
the tally-meter should increase to, say, 2 inches, the valves will be forced into a more
nearly closed position, until equilibrium is again established. The pressure on the
high pressure-plate will then be equal to 2 inches, and the pressure on the low
pressure plate will be equal to of an inch or pressure acting on the other plate.
The square root of 2 equals 1.632. The square root of equals 816 and dividing
1.632 by 816, we that the ratio of the flow through the valves is 2, the same as
where the absorption of the tally-meter was 1 inch.
In Figure 3 I show another form, wherein the diaphragm 10 is placed in a
diaphragin-chamber 19¹ at the inlet-end of the meter, the diaphragm rod 20 con-
necting with the bell-crank 21, which is connected with the rod 71 of the inlet-
valve 6. The pipe 12¹ leads from the inlet side of the meter to the tally-meter 11!,
and from the tally-meter leads the pipe 12 to the meter delivery valve 141, the
pipe 181 leading to the diaphragın-chamber. In this form, the inlet-valve seats in
opposition to the fluid current, whereas in Figure 1 it seats with the current, the
direction which it moves in seating being immaterial; the action will evidently be
the same as in the form of Figure 1.
In Figure 4 I show a form which may be employed, where the area of the direct
delivery-valve is insufficient where this valve is small and the friction of the moving
parts is large. In this form I employ an auxiliary diaphragm 22, in the diaphragm
chamber 23, to which leads a pipe 24 from the inlet end of the meter. The
diaphragm 22 is connected to the diaphragm 1011 by the rod 20" which is connected
by the bell-crank 21" to the rod 711 of the main inlet-valve 611. It is evident that
in this form the entering fluid pressing upon the high pressure-plate 61, will pass
through the pipe 24, and acting upon the diaphragm 22, will act in conjunction with
the inlet-valve, their two effective areas being opposed by the area of the
diaphragm 1011.
In Figure 5 I show a form similar to that of Figure 4, except that the direct
inlet-valve 611 seats in opposition to the fluid current, the bell-crank 21 being
correspondingly changed, so that the diaphragm 22111 will co-operate with the same,
the effective areas of these high pressure-plates being opposed by the low pressure-
plate 10111.
It is evident that in all these forms the principle of operation is identical; that is,
the drop in pressure through the direct delivery valve is so regulated that the drop
in pressure through the meter delivery valve will always be the same fractional part
of it; and in every form is employed the elements necessary to carrying out this
principle, namely, one or more pressure plates which are opposed by one or more

page_text: pressure plates acted upon by the fluid which has passed through the tally-meter.
It is evident that the high pressure-plate may be constituted by the inlet valve itself,
or by some other diaphragm or valve acted upon by the fluid, or by a combination of
the two.
By the word "pressure plate" in the claims, I intend to cover any form of
diaphragm, valve or plate, which is acted upon by the fluid and is so connected as to
carry out the principle of my invention, whether this pressure-plate is constituted by
the valve or valves, or by an element separate therefrom.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is-
1. A proportional meter containing oppositely acting pressure-plates connected to
each other, said plates controlling by their balance the valves for the measured and
unmeasured currents of fluid.
2. A proportional meter containing a valve controlling the flow of measured fluid
from the measuring instrument, and having oppositely acting pressure-plates con-
nected to and arranged to control said valve.
3. A proportional meter containing a valve controlling the flow of the unmeasured
current of fluid, and another valve controlling the flow of measured fluid passing
from the measuring instrument, said meter having oppositely acting pressure-plates
connected to and arranged to control both the said valves.
4. In a proportional meter, a valve controlling the direct inlet to the delivery-
chamber, a pressure-plate acted upon by the entering gas, and a second pressure-
plate acted upon by the gas which has passed through the tally-meter, said pressure
plate being arranged to control the direct inlet valve.
5. In a proportional meter, the combination with a valve controlling a direct inlet
to the delivery-chamber, said valve constituting a pressure-plate acted upon by the
entering gas, of a second pressure-plate acted upon by the gas which has passed the
tally-meter, a valve controlled passage from the tally-meter to the delivery-chamber,
and connections between the direct delivery and meter delivery valves and the low
pressure-plate.
6. In a proportional meter, the combination with a direct inlet-valve arranged to
close in the direction of the current, said valve acting as a pressure-plate acted upon
by the entering fluid; of a tally-meter connected to the inlet-end of the proportional-
meter; a pipe leading from the tally-meter delivery to a meter delivery-valve open-
ing into the delivery-chamber, a pipe leading from the tally-meter to a chamber
containing a low pressure-plate, and actuating connections between the two valves
and the low pressure-plate.