Improvements in Proportional Meters.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Proportional Meters.
I FRED E. YOUNGS, of Pittsburg, in the County of Allegheny, and State of
Pennsylvania, United States of America, Mechanical Engineer, do hereby declare the
nature of this invention and in what manner the same is to be performed to he
particularly described and ascertained in and by the following statement :-
This invention consists in the combination of an inlet chamber, a proportional
valve operated by a diaphragm, a prossure equalizing valve also operated by a
diaphragm, a tally meter, and an outlet passage or chamber; all of which will be
more fully described hereinafter.
The object of my invention is to provide a proportional meter which will accurately
maintain the ratio between the measured and unmeasured portions of the gas without
regard to changes of pressure or changes of volume or amount of flow, of course
within the limits of the capacity of the meter, and which will absorb but a very
small amount of the flowing pressure of the gas or fluid.
In the drawing, Fig. I, is a sectional elevation of a meter embodying my
invention.
Fig. 2 is a modification of the same.
The accuracy of the proportional meters may be said to depend almost on
keeping the ratio between the measured and unmeasured portions of the gas or
fluid, constant or invariable. In proportional meters as usually constructed, a serious
difficulty has been encountered in maintaining this ratio, owing to the fact that the
friction in the tally meter is a variable quantity sometimes more and sometimes less,
changing with the different conditions of pressure and volume of gas or fluid flowing
through the meter. Muny ways have been suggested for overcoming this difficulty,
but the objection to the most of thein lies in the fact that they cause the device
or meter to absorb too much of the pressure of the gas or fluid in passing
through it.
A, is the inlet-pipe; B, the inlet-chamber; C, a proportional valve; D, the
diaphragm, which operates the proportional valve; E a balance valve operated by
the diaphragm F; G, the tally meter feeding chamber; H, the chamber into which
the unmeasured gas flows; I, the outlet chamber; J, the outlet pipe; K, the tally
meter. In operation the gas or fluid enters through the inlet pipe A, into the inlet
chamber B, where a small but definite portion of the gas or fluid flowing through the
device passes through the small opening of the proportional valve C, into the meter
feeding chamber G; thence it passes through the tally meter K, to the outlet
chamber I. The larger portion of the gas passes from the inlet chamber B, through
the larger opening in the proportional valve C into the chamber H, thence through
the balance valve E, to the outlet chamber I, where it again mingles with the
measured portion of the gas, and leaves the device through the outlet coupling J.
The diaphragm D, in Fig. 1, is counter-weighted in any suitable manner, or as here
shown, by the lever and ball L, or as shown in Fig. 2, the diaphragm is placed at
the top of the inlet chamber above the levers M, and rods N and O. "This diaphragm
is connected to the proportional valve of any preferred form or construction by the
bell crank lever M, and the connecting rods N, O. The pressure of the gas in the
inlet chamber B, has a tendency to press down in Fig. 1, or up in Fig. 2, and by
the action of the lever M, to open the proportional valve C. This action is resisted
by the action of the lever and weight L, Fig. 1, or weight L, Fig. 2.
valve C, is opened by the pressure of the gas in the chamber B, a portion of the
pressure of the gas passes through into the chambers H and G. The pressure in
the chamber H, combined with the action of the weight L, balances the pressure in
the chamber B, but the pressure in the chamber H, will be less than the pressure
When the

page_text: in the chamber B, by an amount depending on the size or weight of the weight L.
The pressure of the portion of the gas, which passes through the small opening C³,
in the proportional valve into the meter K, is backed up or throttled by the friction
of the meter which throttles or obstructs the flow of the gas or fluid; or in other
words if the friction of the meter K, were say one-fourth of an inch water pressure,
the pressure in the chamber G, would be higher than in the chamber I, by one-
fourth inch.
•
If it were not for the action of the diaphragm F, and balance valve E, the pressure
in the chambers I, and H, would be the same, or in other words the fall in the
pressure of the gas or fluid in passing through the two openings in the proportional
valve C, and would he unequal. The fall in prossure of the gas or fluid in
passing from the chamber B, into the chambers E and I, would be more than the
fall in prossure in passing from the chamber B, into the chamber G, by the amount
of the friction of the tally meter K, which in the case supposed above was one-
fourth inch. Now the pressure of the gas in the chamber G, pressing against the
diaphragm F, has a tendency to close the balance valve E, while the pressure in the
chamber H, on the other side of the tally meter K, and diaphragm Facts to open
the balance valve E, while the friction of the tally meter K, throttling or backing
up the pressure into the chamber G, bas a tendency to make it higher than the
chamber H. The excess of pressure in the chamber (i, crowds the diaphragm F,
over and closes or partially closes the balance valve E. This has the effect of
throttling the flow of the gas or fluid from the chamber H, into the chamber I,
until the pressure in the chamber H becomes the same as the pressure in the
chamber G. The diaphragm F, is hung in any suitable manner so as to move the
valve E, back and forth with as little friction as possible. If it were mechanically
possible to operate this balancing diaphragm F, and the balancing valve E, with
absolutely no friction, the pressure in the chambers H and G, would be at all times,
and under all conditions of flow absolutely the same. Then the diaphragm D', and
proportional valve C, could be dispensed with and an opening made from the
chamber B, into the chamber H, of a certain size, and an opening made from the
chamber B, into the chamber G, of any other suitable size smaller than the opening
into the chamber H. The flow of the gas then from the chamber B, into the
chambers H, and G, would always be in the ratio of the areas of these two openings;
but owing to the fact that there will always be more or less friction, the motion of
the diaphragm F and the balance valve C, will cause a very minute difference in
the pressure in the chambers H, and G. In case of a very small flow of volume
passing through the device the fall in pressure in passing from the chamber B, into
the chamber H, and G, might become so small that the error in balancing the
pressure in the chambers H and G, by the diaphragm F and the balance valve E,
would exceed the fall in pressure through the orifices between the chamber B, and
chambers H and G. This being the case the gas or fluid would either flow all
through the chamber H, to the outlet J, and none pass through the meter K, or
in case the error was the other way, the whole volume might pass through the
chamber G, and meter K. Now it is only necessary to insure enough fall in
pressure in passing from the chamber B, into the chambers H and G, to make this
minute error a small factor of the total fall in pressure through the valve C. The
volume of gas in passing through an orifice with differing falls of pressure, varies
about as the square root of the fall in pressure. This being the case of the fall in
pressure in passing from the chamber B, into the chamber H, is a certain definite
aniount, and the fall n pressure in passing from the chamber B, into the chamber G,
is the same minus or plus the error due to the friction of the diaphragm F, and the
balance valve E. The error caused in the flow into the two chambers will vary as
the square root of the fall in pressure in passing into the chambers. I have found
that it is perfectly practical to keep the pressure in the chambers H and G, within
one-hundredth of an inch water pressure of each other, this being the case the
actual fall in pressure in passing from the chamber B, into the chambers H and G,
may be made very low.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what i
claim is:
The combination in a proportional meter, of an inlet chainber, a balance chamber,
ameter feeding chamber, and outlet chamber, a weighted diaphragm placed
between the inlet chamber and the balance chamber, a proportional valve placed
with the large opening leading to the balance chamber and the small opening leading
to the meter feeding chamber, and operated by the weighted diaphragm, a balance
valve placed between the balance chamber and the outlet chamber, a diaphragm
placed between the meter feeding chamber and the balance chamber and operating
the balance valve and a tally meter placed or connected between the meter feeding
chamber and the outlet chamber substantially as shown.
C1080
WE WHEN
HERBERT & Co.,
18, Buckingham Street, Strand, W.C., London, Agents to Applicant.