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Патент USA US2403867

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July 9, 1946.
'
’
‘ '
D. E. LIPFERT ‘
FLOW
'
METER
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‘ Filed Nov. 30., 1943
2,403,867
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2 Sheets-Sheet 1
A
’
INVE NT OR
Damn . E LmFE'RT
July 9, 1946.
D. E. LIPFERT
2,403,867 -
I FLOW METER
Filed Nov. 30, 1943.
2_She'ets-.-Sheet 2
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INVEN+OR
.DMVALD E Lumen?"
AGENT
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Patented July 9, ‘1946
2,403,867 v
V UNITED
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STATES
r
PATENT’ OFFICE ‘
2,403,867
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i
FLOWMETER >>
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7'
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Donald E. Lipfert, Mel-idem] Conn; assignor to,
Chandler-Evans Corporation,- South 'Meriden, ;
Conn., a corporation of Delaware
7
Application November 30, 1943, Serial No. ‘512,309’
' 10 Claims.
1
(or. 734532)
2
.
Figure 1 is a somewhat diagrammatic illustra
tion of the ?uid flow measuring system utilizing
This invention relates to‘meter‘s for measuring '
the ?ow of ?uid in a conduit.
Flow meters of the type in which the measur
ing-element is rotated in accordance with the,
the principles of my invention,
1
Figure 2 illustrates a modi?cation, and
speed of the ?uid ?owing pastit are subject to 5
Figure’3 illustrates another modi?cation.
Referring to Figure 1, there is shown a conduit
error because of the leakage of’ the ?uid past
l0, ‘thru which a flow of ?uid is induced by a
the meter element. This leakage varies with‘ the
pressure differential across the meter element and
pump I2 driven by a motor l4.. A ?ow meter [6, of
any suitable rotary displacement type, is con
hence is difficult to take into account in the
calibration of the meter. It has'been proposed 10 nected in the conduit I0. A branch conduit I8
, conveys a, portion of the ?uid discharged by the
to drive such a meter from an external source
of power so that the pressure differential across
_ pump to a?uid motor 20 and thence thru a
the meter is maintained constant. The error due
conduit 22 back to the inlet side of the pump I 2.
_The:fluid motor 20 rotates a. shaft 30 con
to leakage past the meter element is therefore‘
also maintained constant and may be readily l 15' nectedto the flow meter I6. Ayfriction brake
member 28 is ?xed onv the shaft Wand cooper
compensated by proper calibration of the meter;
Prior devices of this type vcould be used only with I ates with a-relatively' stationary brake, member
a motor driven by an external source of power,
and hence would be limited in their application to
places wheresuch external sources were avail
able. Furthermore, the apparatus requiredwhere
such an external source is used tends to be large
and unwieldy.
_
go
26.‘ The brake member, 26 is held against rota
tion by'guides 24. The brake members 26 and
28 are held in engagementwith a'variable force
which depends upon the pressure differential
across the flow meter IS.
A pressure di?erential responsive device gen
a
An object of the present invention is to provide
. erally indicated at 32 includes a casing 34 divided
improved flow measuring means.
.25 by a ?exible diaphragm 36 into a pair of ex
Another object is to provide a rotary ?owmeter I f'pansible chambers 3-8 and 40. The chamber 38
including means for driving the rotating element
is connected thru a conduit 42 and the conduit 18
of the flow meter by utilizing ‘power- taken from
to the conduit ID at the upstream side‘of ?ow
meter 16. The ‘chamber 43 is connected thru a
ther?uid stream being measured, and at the same
time viriainigaining a substantially constant pres 30 conduit 44 to the conduit 10 at the downstream
sure differential across-the rotary element.
‘ side of the ?ow meter [6. A spring 46 is retained
Anotherobject is to provide fluid‘ flow measur
ing means including a rotary meter element'of
between diaphragm 36 and the housing 34, and
another spring 48 is retained between the dia
the displacement type, and a fluid motor for driv
phragm 36' and the clutch member 26.
ing the meter, and means for controlling the 35 The pressure of the ?uid discharged by the
speed at'which the motor drives the meter ele
pump 12 is controlled by a relief valve generally
ment in accordance with the pressure drop across
indicated at ‘50. The relief valve 50 includes a
housing 52 having 'a partition 54 extending across
the element.
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A further object is to provide ?ow measuring
it.‘ A‘ valve 56 seats in an opening in the parti
means of the type described in which the meter 40 tion. '.A ?exible‘ diaphragm 58 extends across
speed is controlled by varying the loading on a
friction brake which is attached to the motor
shaft.
_
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'
.
A further object is to provide an improved sys
tem for measuring the flow of ?uid supplied by a
pump provided with a by-pass valve for control
ling the discharge pressure,. including a rotary
?ow meter, a ?uid motor connected across-the
pump for driving the flow meter, and means re
spo'nsiveto the pressuredi?erential across the
flow meter for controlling the by-pass valve.
'
Other objects and advantages of the present
invention will become apparent from a considera
tion of the appended speci?cation, claims and
drawings, in which
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>
the casing 52 forming a chamber 66 between
the diaphragm 58 and partition 54 and a chamber
'62 between the diaphragmi? andlcasing 52.‘ ‘The
chamber 62 is vented, as at 64, to the atmosphere,
or to any suitable source of substantially con
stant pressure. A spring 13 is retained in cham
ber 62 between diaphragm 58 and housing 52.
The chamber 60 is connected thru a conduit 66
to the discharge side of the pump l2, and a cham
50. ber 69 onthe oppositefside of partition 54 from
.‘chamber 60 is connected thru a conduit ‘68 to the
inlet side of pump I2.
The relief valve 50 operates in accordance with _
well-known principles to ‘maintain a substan
55. tially constant pressure at the discharge'side 01f
2,408,867
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3
The valve I35 seats against the edge of the open
ing of conduit II8 into chamber I32. A spring
I38 is retained between the diaphragm I30 and
the casing I20 in the chamber I34, and biases
pump I2. The value of this pressure depends
upon the strength of spring ‘I0. If desired, means
may be provided for adjusting the initial loading
of the spring ‘I0.
‘
5 the valve I36 towards closed position thru the
stem I28, which also is attached to the center
As long as the ‘quantity of ?uid ?owing thru
of diaphragm I30. Means may be provided for
adjusting the loading or spring I38. .
the conduit 1c remains constant‘, the speed of,
flow meter It remains constant and may be indi
rI’he chamber I34 is vented, as at I40, to at
cated or recorded by any suitable apparatus for lOmosphere or any other source of substantially
measuring the velocity of a rotating element.
constant pressure. The chamber I32 is con
Since the power for rotating the meter I6 is sup
. nected thru a conduit I42 to the inlet side of
plied by the motor 20, the amount of power re
pump. I02. The chamber I24 is connected thru
quired by the particular indicating or recording
a-conduit vHi5‘ to the downstream side of meter
apparatus used does not aiiect the meter reading, . 1 5. I05‘; The chamber I25 is vented to the atmos
as the motor 20 will supply any amount of power ‘ ' 'phere at ‘I45, and the chamber I26 is connected
thru a conduit 'I46‘to'the upstream side of meter
necessary to rotate the meter and itsassociated '
indicating or recording apparatus at the speed _ _ I66.
Operation of Figure 1
he double diaphragm construction and the
required to maintain a substantially constant -
‘ 20 chamber I25 are provided to eliminate difficulties
pressure drop across the meter.
If the quantity of ?uid ?owing thru conduit: I0
which may occur when a single diaphragm is
used and the loading on spring I38 is very small.
increases, the pressure drop across the ?ow meter
I0 tends to increase. This pressure differential,
Under such conditions, the system maintains a
acting on diaphragm 36, moves the latter down
very small pressure differential across the ?ow
wardly, thereby decreasing the braking force 25-“.meter, and when the ?ow is changing, the di
which opposes motor 20, and causing the speed
rection of the resultant force may reverse. If a
of the meter to increase until the pressure differ—
single diaphragm is used, the direction of the
ential across it is restored to its previous value.
- , bulge in the diaphragm reverses at such times.
Strictly speaking, the pressure differential
If the volumetric capacity of the bulge is appre
across the meter is not restored to its exact pre gdi'ciable as compared to the capacity of conduits
vious value. It may be observed that the braking
Hi4 ‘and I46, ‘as is usually the case, then the
force applied varies inversely as the-pressure dif- .
change in direction of the bulge delays the move
ferential across the meter. Because of the Very
ment of the valve I36‘until the quantity of ?uid
small travel of diaphragm 36 required to produce
a substantial-‘variation inthe braking force,-a
necessary to make ‘up for the change in the rela
‘tive- capacities of chambers I 24 and I26 has moved
thru the conduits I04 and I46. This time lag
small variation in the pressure differential across‘
the meter is sumcient to cause a variation of the
may cause an‘ undesirable “hunting” condition to
braking force throughout its effective range.
Therefore, an increase in the quantity of ?uid
be initiated, wherein the diaphragm ?aps back
‘and forth from one direction to the other, result
?owing results in a small increase in the pres
40 mg in ?uctuating operation of the-meter. '
By' using the'double diaphragm construction
and the intermediate vented chamber I25, this
force and a consequent increase in the motor and
dif?culty may be avoided, since the pressures in
meter speed proportional to the increase in ?ow.
chambers‘ I24 and I26 are always above atmos
It has been found that by proper design of the 45 pheric and the diaphragms I22 and- I23 always
diaphragm 33 and» the springs 46 and 48, the vari-.
bulge toward-the chamber I25.
sure differential across the meter, just so much '
as is necessary to cause a decrease in the braking
ation in the pressure differential may be made
sumciently small that there is no substantial er- >
ror in the ?ow measurement due to the varying
leakage thru the meter.
p
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1
> Figure 2
'
I
I. Operation of-Figure. 2 . " '
It may-be seen thatthejpressure drop across
'60 the meter;l_i_l6 acts on diaphragms I22 and I23 to
control the valve I36; The‘ diaphragm ISO-is pro
vided to balance the valve I36 against the (pres
sure in chamber I32; The spring I38 establishes
In this ?gure there is shown a conduit I00,'in"'
the value of'the constant pressure differential
which a ?ow of ?uid is induced by a pump I02
driven by a motor I04. A ?ow meter IE5 is con 55 maintainedacross diaphragms I22 and I23.
‘If the quantity of ?uid ?owing thru the vcon
nected in the conduit I00. The flow meter I00‘
duit I00 increases, the vpressure diiferential across
is driven by a ?uid motor I83, which receives its
meter IE3 increases, causing the valve I36 to
move toward closed position, thereby increasing
I02 thru a conduit III). The ?uid discharged by
motor I08 is conveyed by a conduit II2 to the 60 the pressure of the ?uid discharged by pump
motive ?uid from the discharge side of pump
inlet side of pump
I02.
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I02.’ This increased pressure causes the motor
IEO to run faster, thereby increasing the speed
The pressure at the discharge side of pump- I02
of meter I06 until it is again a true measure of
is controlled by a valve mechanism generally in
-_ the ‘quantity of-?uid ?owingrthru conduit I00.
dicated at H4; The valve mechanism H4 in
cludes a housing II? connected by a conduit II8 65 The “pressure differential across the ?ow meter
I06‘ is thereby reduced to the préviouslyestab~
to another housing I20. The housing H6 is
separated'by a pair of diaphragms I22 and I23
into three expansible chambers I24, I25 and I26;
The central portions of the diaphragms I22 and
lished
constant value.
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r
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Strictly speaking, the pressure differential
across ‘themeter is not restored to its exact pre
I23 are attached to a spacer 'block'I2-‘Iand to a 70 vious value.‘ It may be observed-that the motor
valve stem I28 which extends thru the conduit
speed varies directly'as the pressure of the ?uid
I I8 into the housing I20. The housing I20 is sep- "
arated by a ?exible diaphragm I30 into a pair
small travel ‘of valvefl36 required- to (produce a;
discharged'by the pump.
Because of the very
of expansible chambers I32 and I34.- Inside the t ,_ substantial variation in‘ the meter, speed, a small
_ chamber I32, the stem I28 carries a valve‘ I36: 75' variation in the pressure differential across the
2,403,837’;
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meter ‘is sufficientfto cause a variationofsthe.
pressures substantially to its previous ‘value. ’
Simultaneously,'the increase .7 in the pump outlet
pressure causes an increase in the speed of motor
I60‘ and meter I52 which is effective to'reduce
meter speed throughout. its effective :range. '
Therefore, an increase‘ in the quantity of‘ ?uid.
?owing results in a. small increase in ‘the pres.
sure differential across the meter, just so much as
I the'pressure differential thru the meter.’ It has
been‘ found that if the diaphragm I12 and the
valve I64 are- properly‘ proportioned, the speed’
is necessary to cause an increase in the pump
discharge pressure and .a consequent increasein
the motor and meter speed proportional to the
of the‘motor I60 and meter I52 may be main
increase in flow. It has been found that by prop
tained'substantially proportional to the ?uid ?ow.
er design of; the diaphragm I22 andthe spring
' 'While'I: have‘ shown and described certain pre
I38, the variation inthe. pressure differential I ferred embodiments of my invention, other modi-'
may be made su?iciently smallxthat there 'isno'
fications thereof will readily occur to those skilled»
in 'the- art, and I therefore intend my invention
substantial error in the? ?ow~measurement due
to the varying leakage'thru the meter.
-1 to be 1imited'on1y by the appended claims.
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Figure‘)? "
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'I'claim as my invention: - '
'
1. Apparatus for- measuring the l?ow ofv ?uid’
In the ‘modi?cation shown'in Figure 3, the
thru a ‘conduit,<comprising a rotary ?ow meter in '
quantity of ?uid ?owing thru a conduit I5!) is ‘
said conduit, 2. pump for forcing ?uid thru said;
measured by a‘rotary ?ow meter I52. ' This ?ow '
conduit, ?uid motor means for driving said meter, '”
is produced by a pump I55, driven by a motor :56. "20 means for conveying motive ?uid to said motor v
A-portion of the ?uid- discharged by the pump
means from the upstream side of said meter, and‘
I54 is conveyed thru a‘ conduit I58 to a ?uid motor
means responsive to the pressure di?erential '
I69, which drives the meter I52. The-?uid dis
across said meter for controlling the supply of
charged by motor I66 is conveyed thru a conduit
?uid tovsaid motor means.
>
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I
I62 to the inlet of pump I54.
.
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2. Apparatus for measuring the ?ow ‘or ?uidii ,
thru-'a conduit, comprising a rotary ?ow metérin
said conduit,"a pump for forcing ?uidthru said
conduit,'flui_d motor means for driving said meter,
The pressure at the discharge side of pump [5s
is controlled by a relief valve I554. The valve I64
is attached .to a'valve stem IE5-"Whl0h extends?
thru a’ casting I68 into a chamber I76 formed a
means for conveying motive ?uid to said motor ,
’
‘
between the casting I58 and a ?exible diaphragm 30, means from the discharge side of .said pump,
I'I2. Another expansible. chamber I14, 501:1 ‘the
means for conveying‘ ?uid discharged by said
opposite side of diaphragm I‘izyis‘connected thru
motor means'to the inlet side of said pump; ‘and
a conduit» I16. to the downstream side of the ?ow: , means‘ responsive to the pressure differential
meter I52. The chamber H0 is vented, as at Its,
‘across ‘said meter for controlling the pressure
to atmosphere or any other vsuitable source'of
differentialacross said pump.
_
,
substantially constant pressure.
-
On the opposite side of valve I64,'the stem IE8
is attached to the center of a diaphragm
which separates a pair of expansible chambers
I82 and I84 formed in the casting I68.v A spring
I86 is retained between diaphragm I80 and the
casting I68, and biases the valve I64 toward closed
position.
motor means, to the inlet side of said pump, valve
'me'an-s'for by-passing ?uid from the discharge
side to the inlet side of said pump to control the
pressure at said discharge side, and means re
Operation of Figure 3
sponsive to the pressure differential across said
meter for controlling said valve means.
The diaphragm I80 is provided to balance the
4. Apparatus for measuring the ?ow of ?uid
valve I64 against changes in pressure in the 50 thru a conduit, comprising a rotary ?ow meter
chamber I82. The spring I86 establishes a con
in said conduit, a pump for forcing ?uid thru
stant force required to open the valve I64. The
said conduit, ?uid motor means ‘for driving said
pressure at the discharge sideof pump I54 acts
meter, means for conveying motive ?uid tosaid
on the valve I64 in an opening direction. The
motor means from the discharge side of said
pressure on the downstream side vof ?ow meter 65
I52 also acts, thru diaphragm I12, on the valve
I64 in an opening direction.
Since the pump outlet pressure and the meter
outlet pressure act together on the‘valve I64, it
pump, means for conveying ?uid discharged by
said motor means to the inlet side of said pump,
valve means for by-passing ?uid from the dis
charge side‘to the inlet side of said pump to con
maybe seen that the valve I64 regulates the 60 trol the pressure at the discharge side, and means
responsive to the pressure at the downstream
side of said meter for controlling said valve
of that pressure and the meter outlet pressure.
means.
'
Furthermore, the meter outlet pressure varies
5. Apparatus for measuring the ?ow of ?uid
directly with the pump outlet pressure. However,
the meter outlet pressure differs from the pump 65 thru a'conduit, comprising a rotary ?ow meter
in said conduit, ?uid motor means for driving
outlet pressure by ‘the pressure differential across
pump outlet pressure as a function of the sum
the meter.
The pressure differential across the meter tends
said meter, brake means for retarding said motor
means and said meter, means for conveying mo
tive ?uid to said motor means from the upstream
Therefore, an increase in the rate of ?ow results 70 side of said meter and means responsive to the
pressure differentialacross said meter for con
in a decrease in the sum of the pump outlet pres
trolling the force of said brake means to control
sure and the, meter outlet-pressure. This causes
the speed of said motor means.
a closing movement of valve I64 and a consequent
6. Apparatus. for measuring the ?ow‘ of ?uid
"increase in both the pump outlet pressure and the
thru a conduit, comprising a rotary ?ow meter
meter outlet pressure to restore the sum of those
to vary directly with the rate of ?ow, however.
I
I
3. Apparatus for‘measurin'g the flow of ?uid .
thru a conduit; comprising a rotary ?ow meter in.
said conduit, a pump for forcing ?uid thru said
40 conduit, ?uid motor means for driving said meter,
"means for conveying motive ?uid to said motor
means from the discharge side of said pump,
means for conveying ?uid discharged by said
The chamber I82 is connected thrua ~
conduit I88 to the inlet side of pump I54. A con
duit I90 connects the discharge side of pump I56.
to a chamber I92 under the valve I64.
‘
2,408,867 ‘
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insaid conduit, a pump for forcing ?uid thru ; ' - and a second movable wail subject to the pres
said conduit, ?uid motor means for driving said
meter, means for conveying motive ?uid to said
motor means from the discharge side of said
pump, means for conveying ?uid discharged by
said motor means to the inlet side of said pump,
valve means for by-passing ?uid from the dis
charge side to the inlet side of said pump to
control the pressure at the discharge side, means
sure at the upstream side of said meter, at least
the second of said walls being associated with
said valve-means for positioning the same.
9. Apparatus for measuring the ?ow of ?uid
thru a conduit, comprising a rotary flow meter
in said conduit, a pump for forcing ?uid thru
saiduconduit, ?uid motor means for driving said
meter, passage means for conveying a part of
responsive to the'pressure at the downstream side 10 the ?uid discharged by said pump to said motor
means for use therein as a motive ?uid, means for
of said meter for controlling said valve means,
conveying all the fluid discharged by said motor
and means responsive to the pressure at the dis
means to the inlet sideof said pump, valve means
charge side of said pump to additionally control
for by-passing?uid from the discharge side to
'7. Apparatus for measuring the ?ow of ?uid 15 vthe inlet side of said pump, means including a
first movable wall subject to the pressure drop
thru a conduit, comprising a, rotary ?ow meter
across said meter for controlling the speed of
in said conduit, ?uid motor means for driving
said motor means to maintain said pressure drop
said meter, a pump for forcing ?uid thru said
substantially constant, and means for control- '
conduit, means for conveying motive?uid to said
motor means from the upstream side of said 20 ling the pressure at the discharge side of said
pump including a second movable wall subject to.
meter, and means responsive to the pressure dif
the pressure at the upstream side of said meter,
ferential across said meter for controlling the
speed with which said meter is driven by said
and a connection between said second wall and
said valve means for positioning the same.
'motor, said last-named means comprising three
aligned expansible chambers separated by two
10. Apparatus for measuring the ?ow of ?uid
?exible diaphragms, means connecting the end
thru a conduit, comprising a rotary ?ow meter
in said conduit, a pump for forcing ?uid thru
chambers to the opposite sides of said meter, and
means for venting the intermediate chamber.
said conduit, ?uid motor means for driving said
8. Apparatus for measuring the ?ow of ?uid
meter, means 'for conveying motive ?uid to said
thru‘a conduit, comprising a rotary ?ow meter 30 motor means from, the discharge side of said
pump, means for conveying ?uid discharged by,
in said‘ conduit, a pump for forcing ?uid thru
saidmotor means to the inlet side of said pump, .
said conduit, ?uid motor means for driving said
valve means for by-passing ?uid from the dis
meter, passage means for conveying a part of
charge side to the inlet side of said pump, and
thef?uid discharged by said pump to said motor
means for controlling the pressure drop across,
means vfor use therein as a motive ?uid, means
for conveying all the ?uid discharged by said
said meter to maintain said pressure drop sub
stantially constant and for controlling the pres
motor means to the inlet side of said pump, valve
means for by-passing ?uid from the discharge
sure at the discharge side of said pump, said
controlling means including a ?rst movable wall
side to the ‘inlet side of said pump, and means
for controlling the pressure drop across said meter 40 subject to the pressure at the ‘downstream side
to maintain said pressure drop substantially con
or said meter, and a second movable wall sub
ject to the pressure at the upstream side of said
stant and for controlling the pressure at the
discharge side of said pump, said controlling
meter, both of said walls being associated with _
means‘including a ?rst movable wall subject to
said valve means for positioning the same.
DONALD E. LIPFERT.
the pressure at the downstream side of said meter,
said valve means.
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