United States Patent
`4,872,351
`Ruesch
`Oct. 10, 1989
`[45]
`Date of Patent:
`
`[11]
`
`Patent Number:
`
`[191
`
`[54] NET OIL COMPUTER
`
`[75]
`
`Inventor:
`
`James R. Ruesch, Boulder, Colo.
`
`[73] Assignee: Micro Motion Incorporated, Boulder,
`Colo.
`
`[21] App1.No.: 339,128
`
`[22] Filed:
`
`Apr. 14, 1989
`
`Related U.S. Application Data
`
`[63]
`
`Continuation of Ser. No. 235,234, Aug. 23, 1988, aban-
`doned, which is a continuation of Ser. No. 916,780,
`Oct. 9, 1986, abandoned.
`
`G01F 1/74
`Int. Cl.4 .
`[51]
`
`[52] U.S. Cl. .................................... .. 73/861.04
`[58] Field of Search ............ .. 73/861.04, 32 A, 861.35
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,689,989
`
`9/1987 Aslesen et al.
`
`................. .. 73/861.04
`
`Primary Examz'ner—Michael J. Tokar
`Assistant Examiner-—Robert P. Bell
`Attorney, Agent, or Fz'rm—Peter L. Michaelson
`
`[57]
`
`ABSTRACI‘
`
`ing both an accurate densimeter and a net oil computer
`utilizing a common Coriolis meter assembly is de-
`scribed. In essence, this apparatus measures density of
`an unknown fluid by first determining the period at
`which both flow tubes contained within a dual tube
`Coriolis meter oscillate while the unknown fluid passes
`therethrough. This apparatus then squares the result.
`Thereafter, the density of the unknown fluid is deter-
`mined as a linear function that relates the squared tube
`period measurement for the unknown fluid, and squared
`tube period measurements and known density values for
`two known fluids, such as air and water, that have pre-
`viously and successively passed through the meter dur-
`ing calibration. When used as a net oil computer, the
`inventive system obtains mass flow and temperature
`measurements from the same flow tubes. By using mea-
`sured density and mass flow values of an oil-water
`emulsion that flows through the same Coriolis meter,
`the inventive system can advantageously provide both
`volumetric and mass based measurements of the flow
`rate and totalized flow of the entire emulsion and of the
`
`individual water and oil components present therein.
`
`Apparatus and accompanying methods for implement-
`
`36 Claims, 27 Drawing Sheets
`
`A DENSIHETEH
`PROCESSOR
`5_°
`
`cmcx
`1/2 FREQUENCY
`INTERHUPT LINE
`
`
`
`(RAN. Novmc:
`EEPRONI
`537
`
`A/D
`(12 Bill
`
`:
`
`RS-232C
`SIGNALS
`
`TUBE
`tl
`l[ERPERAlURE
`
`PULSE NIDTH TO
`
`A-20 mA CONVERTER PULSE NIDlH TO
`
`I
`4-20 In CONVERTER
`‘
`________ __Aw_s_MPyI_cu9uI1i‘56°A-20 mA PROCESS SIGNALS
`DISPLAV
`(Y0 PROCESS
`*;*> DISPLAY
`CONTROL EOUIPHENU
`/540
`57:
`KEYBOARD
`KEYBOARD
`ENCODER
`
`C573
`
`:577
`
`575
`
`511
`
`
`
`
`
`RTD
` LINEARIZING
`
`AND SCALING
`
`CIRCUIY
`536
`
`
`
`
`1
`
`TUBE venmn.
`CLOCK
`[
`L _____________ .£‘§l1“%'iL C_1“€”_1h'
`5E5
`
`= 515131
`CLOCK
`
`SEO
`
`CLOCK
`SIGNALS
`
`vfk DATA AND
`ADDRESS ausszs
`
`1
`1
`
`Micro Motion 1020
`
`Micro Motion 1020
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 1 of 27
`
`4,872,351
`
`U?
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`FIG.1
`
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`
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`
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`
`RTDSIGNAL
`
`
`
`1559155L
`
`195
`
`
`
`2
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 2 of 27
`
`4,872,351
`
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`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 3 of 27
`
`4,872,351
`
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`
`U.S. Patent
`
`Oct. 10,1989
`
`Sheet 4 of 27
`FIG. 3A
`ELON (POSITIVE DIRECTION)
`_.________________._____________________.*x_________..__________..___________.._.\
`
`4,872,351
`
`VELOCITY
`NAVEFORMS
`
`.
`
`LEFT VELOCITY
`SIGNAL
`
`RIGHT VELOCITY
`SIGNAL
`
`INVERTED LEFT
`POSITION SIGNAL
`
`POSITION WAVEFORMS
`
`INVERTED RIGHT
`POSITION SIGNAL
`
`
`
`START INTEGRATE. DOWN
`
`STOP INTEGRATE. UP
`
`VL"']
`
`}"""""'{
`
`%r—’
`SAMPLE
`
`T"*""""1
`
`["
`
`STOP INTEGRATE, OONN
`VR
`
`START INTEGHATE, Up
`
`RESET
`/T
`
`OUTPUT FROM
`INTEGHATDR 345
`
`+V
`
`“at
`
`ZERO VOLTAGE
`
`5
`
`

`
`U.S. Patent
`
`Oct. 10,1989
`
`Sheet 5 of 27
`
`4,872,351
`
`FIG. 3B
`N0 FLOW
`
`LEFT AND RIGHT
`
`VELOCITY
`
`NAVEFORMS
`
`"-\\\\"__—"l/,»»—--~.\\\\~___"’//,»""“-\\<:i_-
`
`VELOCITY SIGNALS
`
`POSITION
`
`NAVEFORMS
`
`\\‘_”///’//’T—T\\\\\\\\_—’/O/’//ET-T\\\‘\\\\_'/37/’
`
`INVERTED LEFT AND RIGHT
`POSITION SIGNALS
`
`
`
`START INTEGRATE, DONN
`
`STOP INTEGRATE, UP
`
`VL
`
`*—y—J
`SAMPLE
`
`STOP INTEGRATE, OONN
`
`START INTEGRATE’ Up
`
`OUTPUT FROM
`
`[\INTEGRATOR 345
`
`ZERO VOLTAGE
`
`6
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 6 of 27
`
`4,872,351
`
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`

`
`U.S. Patent
`
`4,872,351
`
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`72:1
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`4,872,351
`
`U.S. Patent
`
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`

`
`U.S. Patent
`
`Oct. 10,1989
`
`Sheet 9 of 27
`
`4,872,351
`
`FIG. 7
`
`MAIN PROGRAM
`
`70_0
`
`ENTER
`
`0 POWER ow RESET
`
`INITIALIZE
`
`pp SYSTEM
`
`720
`
`INCLUDING BAUD RATE
`READ CONSTANT DATA.
`AND DECIMAL POINT LOCATION,
`FROM NOVRAM
`AND STORE IN RAM
`
` CONFIGURE AND
`
`
`PROGRAM SERIAL CIRCUITRY IN
`MICROPROCESSOR NITH BAUD RATE
`
`730
`
`P TIMER TO
`SET UP
`GENERATE AN INTERRUPT EVERY 20 mSEC
`
`INTERRUPT SERVICING
`
`740
`
`UNMASK ALL INTERRUPTS
`
`
`
`
`
`INTERRUPT
`OCCUR?
`
`INTERRUPT
`
`PROCESS
`
`76
`
`O
`
`10
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`4,872,351
`
`Sheet 10 of 27
`ENCE OF
`
`ENTER EREUUENCY IN
`
`PT
`
`FIG. 8
`
`TUBE PE
`INTERRUPT
`B00
`
`NE
`
`A
`
` HAS
`BEEN
`
`PREVIOUS TUBE
`PERIOD MEASUR
`EMENT
`
`
`
` B10
`
`NO
`
`EXIT
`
`0
`
`COMPLETED?
`
`READ 16 BIT PERIOD
`MEASUREMENT FROM
`COUNTER 535
`
`E
`
`840
`
`RESET COUNTER 535
`
`FORM 2'3 COMPLEMENT TO
`YIELD UPCOUNT,C,FOR
`CURRENT PERIOD
`
`RECURSIVELY FILTER
`COUNT,C,FOR CURRENT PERIOD
`
`SAVE FILTERED CURRENT PERIOD
`VALUE. Pf,
`IN MEMORY
`
`850
`
`860
`
`37°
`
`rn>< i—I ——a
`
`11
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 11 of 27
`
`4,872,351
`
`FIG_ 9
`
`
`
`ENTER
`0 20 msec INTERRUPT
`903
`
`READ NEM VALUES,
`
`IF ANY,
`
`FRUM KEYBOARD
`905
`
`INCREMENT PASS COUNTER,
`m
`m+1
`
`m
`
`A
`
`20
`
`FIG. 9A
`INTERRUPT
`UTINE
`EAR?
`
`READ EILTERED TUBE PERIOD VALUE. PE
`FROM MEMORY AND SDUARE VALUE TO
`YIELD Tmz,
`STORE RESULT IN MEMORY
`
`90
`
`9
`
`911
`
`READ DIGITAL VALUE OF CURRENT TUBE TEMPERATURE
`t,
`(REFERENCED TO 0°C)
`FROM A/D CONVERTER
`
`91B
`
`RE
`)
`
`SET:
`TEMPSIGN
`
`"FF"
`
`915[TEMP
`BELO
`
`
` SIGN
`BIT OF
`t
`
`
`NEGATIVE?
`
`NO
`
`921
`
`CALCULATE TUBE TEMPERATURE FACTOR,tL
`FOR FLUID BEING MEASURED
`tf
`225*
`t
`
`925
`
`923
`YES
`
`CALCULATE TEMPERATURE CUEFFICIENT
`tcm,
`FUR FLUID BEING MEASURER
`tcm
`(1*I07)
`+ tf
`
`N0
`
`
`
`tcm
`
`CALCULATE TEMPERATURE COEFFICIENT,
`FOR FLUIU BEING MEASURED
`tcm
`(1*107} - tf
`
`
`
`929
`
`CALCULATE
`tCmTm2
`tcmATm’
`C STORE RESULT IN MEMORY
`
`932
`
`NO
`
`CALIBRATION?
`
`YES
`
`12
`
`

`
`‘US. Patent
`
`Oct. 10, 1989
`
`Sheet 12 of 27
`
`4,872,351
`
`F “““““““““““““ ‘"1
`
`
`
`i Y
`
`FIG. 93
`
`[F'L"o‘w‘“‘"]
`‘CALIBRATION
`ROUTINE
`1940
`
`
`SET
`
`tca T32
`tc,,,I,,,2
`
`O STORE IN MEMORY AS
`
`A CONSTANT
`
` READ AIR DENSITY VALUE
`da,
`FROM KEYBOARD C STORE
`IN MEMORY AS A CONSTANT
`
`
`
`
`
`SET:
`
`
`
`tCwTw2
`
`
`tCmTm2
`
`
`
`SET:
`
`tCwTw2'tCaTa2
`D
`N STORE IN MEMORY AS A CONSTANT
`
`
`
`aw,
`READ WATER DENSITY VALUE,
`FROM KEYBOARD C STORE IN
`MEMORY AS A CONSTANT
`
`949
`
`951
`
`953
`
`CALCULATE:
`
`n,,—aa & STORE IN
`d
`____“§M_°fl"_3_A CONSIBYL ______ _ __J
`
`951
`
`CALCULATE
`
`'
`
`‘tCaTa2)
`NlCmTm2
`N
`C STORE RESULT IN MEMORY
`
`964
`
`YES
`
`967
`
`"FE"
`
`SET:
`BENSSIGN
`
`N0
`
`13
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 13 of 27
`
`4,872,351
`
`
`
`959
`
`
`
`
`
`CALCULATEI
`
`
`
`O STORE RESULT IN MEMORY
`
`FIG. 9C
`
`
`
`
`
`
`NO [DENSSIGN="FFU
`
`972
`
`DENSSIGN
`=II00|l?
`
`CALCULATE
`
`
`CALCULATE
`da‘dint
`
`dm
`0int‘da
`
`
`
`
`
`
`
`
`CALCULATE DENSITY
`‘ OF MEASURED
`FLUID,
`dm, AS
`dm
`dint+da
`
`
`
`CONVERT dn}TO DESIRED UNIT
`IF NOT SPECIFIC GRAVITY.
`Um
`Om*S
`NHERE 3 IS APPROPRIATE
`SCALING FACTOR
`
` NET
`OIL COMPUTER?
`
`
`
`EXECUTE DRT PARAMETER
`CALCULATION AND TRANSMISSION
`ROUTINE 1000
`-
`
`
`
`
`
`14
`
`

`
`U.S. Patent
`
`Oct. 10,1989
`
`Sheet 14 of 27
`
`4,872,351
`
`FIG. 9D
`
`987
`
`
`
`
`m = 20?
`(20th PASS THROUGH
`20 msec INTERRUPT
`
`
`
`ROUTINE)
`
`994
`
`
`
`UPDATE DISPLAYS
`WITH NEW VALUES DF
`
`T,&
`TEMPERATURE,
`(SCALED) MEASURED DENSITY,dm
`
`
`
`
`
`UPDATE OUTPUT SIGNALS
`WITH NEW VALUES OF
`
`D
`t,
`TEMPERATURE,
`(SEALED) MEASURED DENSITY,dm
`
`
`
`RESET PASS
`0 EX”
`
`
`
`couwren m 0
`
`
`
`15
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 15 of 27
`
`4,872,351
`
`1010
`
`
`
`
`
`dm, CALCULATE
`USING MEASURED DENSITY,
`MASS TO VOLUME CONVERSION FACTOR, MASS CONVERT
`FOR CRUDE OIL AS
`
`FIG. 10
`
`DRT PARAMETER
`CALCULATION AND
`TRANSMISSION ROUTINE
`
`1999
`
`MASS CONVERT
`
`AND STORE RESULT IN NOVRAM
`
`
`
` (A07B)H
`(2710) H*dm
`
`
`
`
` EXECUTE TEMPERATURE COMPENSATED
`OIL DENSITY ROUTINE 1100
`TO YIELD VALUE OF TEMPERATURE
`COMPENSATED OIL DENSITY I t 0i1)H
`
`
`
`1020
`
`
`
`
`
`
`
`EXECUTE TEMPERATURE COMPENSATED
`HATER DENSITY ROUTINE 1200
`TO YIELD VALUE OF TEMPERATURE
`COMPENSATED NATER DENSITY T t Mater)H
`
`
`
`
`103°
`
`
`
`1040
`
`1050
`
`1050
`
`
`am,
`GIVEN MEASURED DENSITY,
`CALCULATE MATER CUT, MC, AS
`d
`_
`.
`WC
`m
`I t 011)H
`_
`I t MaterIR"l
`t ULTJR
`
`
`
`
`
`
`
`CALCULATE OIL AND MATER
`DENSITY RATIDS,DRDi1 C DRwatBF
`( t Di1)H
`
`DR ‘
`
`1-WC‘
`
`
`
`
`
`
`
`
`
`
`t waterIH
`A
`I water 60TH
`NC*
`Dnwater
`
`C STORE IN NOVRAM
`
`
`
`
`
`
`
`
`
`
`SERIALLY TRANSMIT VALUES
`OF MASS CONVERT, DR OIIU DRwater
`TO DRT 60
`
`
`
`
`
`16
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 16 of 27
`
`4,872,351
`
`FIG.
`
`11A
`
`TEMPERATURE
`CUMPENSATED OIL
`1105 DENSITY ROUTINE
`
`
`
`OBTAIN LATEST VALUE OF REFERENCE
`DENSITY UF CRUDE OIL AT 60°F (011 50)
`
`ENTERED THROUGH KE¥BOAHD AS 5
`INTEGERS (1.9. 10 X 011 50
`
`
`
`
`CONVERT LATEST VALUE OF
`10‘ 011 50 TU EQUIVALENT HEX INTEGER.K
`[i.e. 271oR( 111 6oH)} 1 STORE IN NUVRAM
`
`
`
`E STORE RESULT IN NOVRAM
`
`FIG.
`
`11
`
`FIG. 111
`
`FIG. 118
`
`FIG. 11C
`
`17
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 17 of 27
`
`4,872,351
`
`
`
`FIG. 11B
`
`1140
`
`
`TLUU
`TUBE TEMPERATURE,
`
`t
`
`
`
`
`
`
`
`
`,
`
`
`CALCULATE‘
`
`
`
`
` CALCULATE
`12-38H — ta/d
`J
`
`
`
`
`
`1150
`
`CALCULATE
`
`A
`
`A1 A J
`
`1160
`
` CALCULATE
`J
`NMH-A
`
`
`
`CALCULATE
`
`J
`
`A — 2710A
`
`
`
`
`CALCULATE
`U
`.001F7H *A2
`
`
`
`
`
`18
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 18 of 27
`
`4,872,351
`
`FIG. 11C
`
`
`
`
`
`
`CALCULATE
`Km—m
`0
`AND STORE IN NOVRAM
`AS TEMPERATURE CUMPENSATED
`OIL DENSITY VALUE I E 011)
`AS 5 INTEGERS (1o‘x A 019
`
`
`
`U
`
`
`
`
`
`2710H
`
`
`
`
`
`AND STORE IN NOVRAM
`AS TEMPERATURE COMPENSATED
`OIL DENSITY VALUE
`
`
`
`
`
`CALCULATE
`
`t 0'11
`
`19
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 19 of 27
`
`4,872,351
`
`12A
`FIG.
`TEMPERATURE
`COMPENSATED
`RATER DENSITY
`ROUTINE gg99
`
`1210
`
`1215
`
`Q ENTER
`
`
`
`
`NEW
`RATER 50
`VALUE OF 10‘
`ENTERED THROUGH
`KEYBOARD?
`
`
` N0
`
`
`
`
`OBTAIN LATEST VALUE OF REFERENCE
`
`
`DENSITY OF SALT NATER AT 60"F
`T NATER 60) ENTERED THROUGH KEYBOARD
`
`
`AS 5 INTEGERS (i.e. 10 x
`RATER 50)
`
`
`
`FIG. 12
`
`FIG.
`
`12A
`
`F15- 133
`
`CONVERT LATEST VALUE or
`To‘ AATEA 50 T0 EQUIVALENT HEX
`INTEGER,P. Ti.e. 271oH( RATER BUHT
`
`
`
`
`
`
`CALCULATE
`L
`
`
`NATEET 60) HEX
`
`P
`2710H
`
`
`O STORE RESULT IN NOVRAM
`
`1260
`
`
`
`
`CALCULATE
`
`FLOR TUBE
`
`
`
`TEMPERATURE,
`>138H?
`
`
`ta/d
`J
`
`
`ta d-138H
`
`
`
`2()
`
`20
`
`

`
`U.S. Patent Oct. 10,1989
`
`L
`
`Sheet 20 of 27
`
`4,872,351
`
`
`
`
`CALCULATE:
`
`J
`
`13BH—ta d
`
`
`CALCULATE:
`
`0
`P -(.1B5A64H x J)-(.000554H * J“)
`
`
`
`
`FIG. 12B
`
`CALCULATE:
`
`1290
`
`
`
`8 STORE IN NUVRAM AS TEMPERATURE
`
`COMPENSATED WATER DENSITY VALUE
`
`t WATER
`
`Q
`271oH
`
`
`
`
`
`
`
`EXIT
`
`21
`
`

`
`U.S. Patent
`
`Oct. 10,1989
`
`Sheet 21 of 27
`
`4,872,351
`
`ENTER
`
`FIG . 13
`
`DIGITAL RATE TOTALIZER
`S DISPLAY
`“AI” PROGRAM
`fll
`
`Q POWER UN RESET
`
`1310
`
`
`
`CIIDINCFHIOGPUAAJECESSSIONHITSVENIETI
`
`
`1320
`
`GET SCALE FACTOR. DECIMAL POINT
`LOCATION C BAUD RATE FROM NOVRAM
`
`MEMORY C STORE IN RAM
`
`
`
`
`
`
`
`1330
`
`
`
`(PRESCALERI
`-PROGRAM COUNTER 625
`USING SCALE FACTOR
`-PROGRAM SERIAL CIRCUITRY IN MICROPROCESSOR
`USING BAUD RATE
`
`
`
`
`-PROGRAM COUNTERS 620 C 630 TO BE DONN
`
`COUNTERS O LOAD THESE COUNTERS WITH VALUE
`"FFFF"
`
`-SET VALUES OF OLOCOUNTO C OLDCOUNT2
`TO "FFFF"
`
`1350
`
`SET UP MICROPROCESSOR TIMER TO
`BENERATE AN INTERRUPT EVERY 20 msec
`
`
`
`I360
`
`INTERRUPT
`SERVICING
`
`
`
`INTERRUPT
`OCCUR?
`
`13
`
`BO
`
`PROCESS
`INTERRUPT
`
`UNMASK ALL INTERRUPTS
`(20 msec C SERIAL INPUT)
`
`22
`
`22
`
`

`
`U.S. Patent
`
`Oct. 10, 1939
`
`Sheet 22 of 27
`
`4,872,351
`
`SEBI
`
`INTERRUPT WEE
`
`PUT
`
`osERIAL1
`
`NPUT
`
`pf
`
`INTERRU
`
`YES
`
`RESET CHARACTER COUNTER
`T0 ZERO
`
` 1410
`
`1415
`
`SET
`REcpLAg
`
`"pp"
`
`RESET
`RECFLAG_
`
`"00"
`
`0 Em
`
`1425
`
`1430
`
`
`
`TRANSFER DATA FROM
`SERIAL BUFFER TO
`CORRESPONDING MEMORY
`LOCATION
`
`0 EXIT
`
`1440
`
`INCREMENT
`CHARACTER
`COUNTER
`
`1445
`
`CONVERT SERIAL
`BYTE FROM
`ASCII TO HEX
`
`1450
`
`STORE HEX
`CHARACTER 10
`SERIAL BUFFER
`
`>
`
`Q EXIT
`
`23
`
`23
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 23 of 27
`
`4,872,351
`
`FIG. 15
`
`ENTER
`Q 20 msec INTEHFTUPT
`1502
`ENABLE INTERRUPTS TO PERMIT
`NESTING OF SERIAL INPUT
`INTEFTRUPT
`
`15A
`FIG.
`DIGITAL RATE
`TOIALIZEFI AND
`DISPLAY
`20 msec INTERFTUPT ROUTINE
`
`1599
`
`1504
`
`DECREMENT PASS COUNTER N
`N
`11-1
`
` FIG. 155
`
`FIG.
`
`1511
`
`FIG. 15E
`
`1505
`
`YES
`
`T" ““““““““““““““““““““““““ ‘"1
`T
`1511
`T
`
`T
`I
`
`T
`
`T
`
`T
`
`T
`
`T
`
`T
`
`T
`
`T
`T
`
`TTIATITI“
`‘
`1510
`
`T
`T
`T
`
`T
`T
`
`T
`
`T
`
`T
`
`T
`
`T
`T
`
`TO 25
`
`1513
`READ CONTENTS OF COUNTER 630
`
`1515
`OLOCOUNTO - NENCOUNTO
`
`OLOCOUNTO
`
`1517
`
`RATE
`
`RATE + OLDCOUNTO
`
`1519
`
`1520
`
`YES
`
`N0
`
`24
`
`24
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 24 of 27
`
`4,872,351
`
`I I I I I
`
`1530
`
`I
`
`FIG. 15B
`
`I522
`
`MULTIPLY RATE BY MASS TO VOLUME CONVERSION
`FACTOR, MASS CONVERT, OBTAINED FROM DENSIMETER
`PROCESSOR TO YIELD MAXIMUM VOLUME
`E VOL R
`RATE * MASS CONVERT
`
`
`
`
`
`
`(WATER VOLUME MODEI
`
`
`
`
`.MULTIPLY MAXIMUM VOLUME BY DIL CUT DENSITY RATIO, DD031,
`OBTAINED FROM DENSIMETEFI PROCESSOR
`T0 YIELD ACTUAL OIL VOLUME:
`
`OIL VOL R E VOL II x DFIQ11
`
`
`
`I I
`
`A I
`
`I I
`
`MULTIPLY MAXIMUM VOLUME BY WATER CUT DENSITY RATIO
`
`
`
`DRwatgp, OBTAINED FROM DENSIMETER PROCESSOR
`TO YIELD ACTUAL NATER VOLUME
`N VDL R
`E VOL R X DR water
`
`
`
`
`1534
`YES
`
`1536
`
`RATE
`
`SET:
`FIDISPLAY
`
`NO
`
`25
`
`I I I I I I I I I I I I I I I I
`
`A
`I
`
`25
`
`

`
`U.S. Patent
`
`Oct. 10,1989
`
`Sheet 25 of 27 E 4,872,351
`
`I 1 1 1 1 1 1 1 1
`
`:
`
`'
`,
`
`'
`
`5
`
`1507
`
`FIG.
`
`1539
`
`YES
`
`1541
`
`SE1
`RDISPLAY
`
`E VOL R
`
`NO
`
`%
`
`SET:
`RDISPLAY
`
`OIL VOL R
`
`
`
`SET:
`RDISPLAY
`
`
`W VOL H
`
`
`15411
`
`CONVERT VALUE or
`
`1151311111 111 BED
`
`1550
`
`DISPLAY CUNVERTED VALUE
`or 11111311111 AS FLOW 11115
`
`1552
`
`SET:
`OLDCUUNTO
`RATE
`OLDCOUNTO
`NEWCUUNTO
`
`26
`
`1 1 1 1 1 1 1 1 1 1 1 1 1
`
`26
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 26 of 27
`
`4,872,351
`
`I 1 T a T i i i
`
`FIG.
`
`15D
`
`
`
` TOTALIZE MASS
`
`MASS TOTAL
`
`MASS TOTAL+
`OLOCOUNT2
`O STORE RESULT IN NOVRAM
`
`1568
`
`MULTIPLY OLOCOUNT2 BY MASS TO
`
`
`
`VOLUME CONVERSION FACTOR, MASS CONVERT
`OBTAINED FROM OENSIMETER PROCESSOR
`TO GET AOOITIONAL EMULSION VOLUME
`NEW EMULSION VOLUME
`NEW EMULSION VOL
`OLOCOUNT2
`* MASS CONVERT
`
`
`
`1570
`
`
`TOTALIZE EMULSION VOLUME
`EMULSION TOTAL
`EMULSION TOTAL +
`
`NEW EMULSION VOL
`& STORE RESULT IN NOVRAM
`
`
`
`1572
`
`CALCULATE NEW OIL VOLUME FROM CURRENT
`EMULSION VOLUME USING TEMPERATURE
`COMPENSATEO OIL OENSITY RATIO, OR0i1
`OBTAINED FROM OENSIMETER PROCESSOR
`
`
`
`
`
`
` NEW OIL
`
`NEH EMULSION VOL 36 090-11
`
`
`
`
`
`
`
`
`TOTALIZE OIL VOLUME
`OIL TOTAL
`OIL TOTAL + NEW OIL
`O STORE RESULT IN NOVRAM
`
`1574
`
`27
`
`
`
`
`
`I a T I T T i T T i 2 1
`
`27
`
`

`
`U.S. Patent
`
`Oct. 10, 1989
`
`Sheet 27 of 27
`
`4,872,351
`
`155
`
`1575
`
`
`
`CALCULATE NEH WATER VOLUME FROM CURRENT EMULSION
`VOLUME USING NATER DENSITY RATIO, Dflwaten
`OBTAINED FROM DENSIMETER PROCESSOR
`
`NEW NATER
`
`NEN EMULSION VOLUME * DR water
`
`
`
`
`
`1578
` TOTALIZE WATER VOLUME
`NATER TOTAL
`NATER TOTAL + NEW WATER
`C STORE RESULT IN NOVRAM
`
`
`
`
`
`
`
`1583
`
`SET:
`1584
`TOTAL
`MASS
`TOTAL
`
`
`SEL
`TOTAL
`EMULSION
`TOTAL
`
`SET:
`
`
`TOTAL
`OIL
`TOTAL
`
`
`
`
`
`NATER TOTAL
`
`
`
`SET:
`TOTAL
`
`
`CONVERT VALUE OF TOTAL TO BCD
`
`28
`
`FIG.
`
`I i T T a T E i T T T T 1 i
`
`28
`
`

`
`1
`
`NET OIL COMPUTER
`
`4,872,351
`
`2
`through. Inasmuch as the total mass will vary as the
`density of the fluid flowing through the tube varies, the
`resonant frequency will likewise vary with any changes
`in density.
`in my US. Pat. No.
`Now, as specifically taught
`4,491,000 (issued Jan. 1, 1985 to the same assignee as the
`present application and hereinafter referred to as the
`’009 patent), the density of an unknown fluid flowing
`through an oscillating flow tube is proportional to the
`square of the period at which the tube resonates. In the
`’009 patent, I described an analog circuit that computes
`density through use of two serially connected integra-
`tors. A reference voltage is applied to the first integra-
`tor. Inasmuch as the spring constant of each flow tube
`varies with temperature and thereby changes the reso-
`nant frequency, the reference voltage is appropriately
`compensated for temperature variations of the tube.
`Both integrators operate for a period of time equivalent
`to the square of the resonant period. In this manner, the
`output signal generated by the analog circuit provides a
`product of a temperature dependent function and the
`square of the value of the resonant period. With appro-
`priate scaling of the reference voltage, the output ana-
`log signal provides a direct readout of the density mea-
`surements (in specific gravity units) of the unknown
`fluid that flows through the flow tube.
`While this circuit provides accurate density measure-
`ments unfortunately it possesses several drawbacks.
`First, for certain applications, density measurements to
`an accuracy of one part in 10,000 are necessary. An
`accuracy of this magnitude is generally not available
`through an analog circuit unless highly precise analog
`components are used. Such components are disadvanta-
`geously quite expensive. Second,
`the analog circuit
`disclosed in the ’009 patent can not be independently
`calibrated to compensate for changing characteristics of
`the electronic components—such as offset, drift, aging
`and the like. Specifically, this circuit is calibrated on a
`“lumped” basis, i.e. by first passing a known fluid, such
`as water,
`through the meter and then adjusting the
`circuit to provide the proper density reading at its out-
`put. This process compensates for any errors that occur
`at the time of calibration that are attributable either to
`physical (empirical) errors in measuring density using a
`Coriolis mass flow meter or to errors generated by the
`changing characteristics of the electrical components
`themselves. Unfortunately, after the circuit has been
`calibrated in this fashion, component characteristics
`will subsequently change over time and thereby inject
`errors into the density readings produced by the circuit.
`This, in turn, will eventually necessitate an entire re-
`calibration. Third, it is often desirable in many applica-
`tions to provide density measurements in units other
`than specific gravity units, e.g. % sucrose (or “brix”)
`for the food industry; API units and/or pounds/barrel
`for the oil industry; and % solids, grams/cubic centime-
`ter
`(cc),
`kilograms/cubic meter,
`pounds/gallon,
`pounds/cubic foot, or the like for other industries. Al-
`though an analog density signal can be readily scaled to
`other units, doing so often necessitates the use of cus-
`tomized circuitry with accompanying added expense.
`In addition, many currently available densimeters do
`not provide density measurements based upon the full
`stream of a process fluid that flows through a process
`line and thus, in many applications, provide inaccurate
`density measurements of the fluid. Specifically, these
`meters disadvantageously utilize flow tubes that have a '
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`
`The reader is referred to my co-pending United
`States patent application entitled “APPARATUS
`AND METHODS FOR MEASURING THE DEN-
`SITY OF AN UNKNOWN FLUID USING CORIO-
`LIS METE ”, Ser. No. 06/916,973, filed Oct. 19, 1989
`now abandoned has been assigned to the present as-
`signee and which claims subject matter described
`herein.
`
`This application is a continuation of my co-pending
`patent application Ser. No. 07/235,234, filed Aug. 28,
`1988, and entitled “NET OIL COMPUTER,” which is
`a continuation of my patent application Ser. No.
`06/916,780, filed Oct. 9, 1986, now abandoned.
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The present invention relates to apparatus and ac-
`companying methods for implementing both an accu-
`rate densimeter and a net oil computer utilizing a com-
`mon Coriolis mass flow rate meter.
`2. Description of the Prior Art
`Very often, the need arises to measure the density of
`a process fluid. This can be seen in two different exam-
`ples. First, in the food industry, liquid sucrose is fre-
`quently used as a sweetening agent in a food sweetener.
`To provide an acceptably sweet taste, the amount of
`sucrose appearing in tho sweetener, and hence the den-
`sity of the sweetener, must fall within a prescribed
`range. Therefore, manufacturers must constantly mea-
`sure the density of the sweetener as it is being manufac-
`tured and accordingly adjust various process parame-
`ters to ensure that the sweetener contains sufficient
`sucrose to produce the proper taste. Second,
`in the
`petroleum industry, the lubricating ability of oil is re-
`lated to its density which changes with temperature.
`Thus,
`to ensure that a quantity of oil will provide
`proper lubrication in a given application, the density of
`the oil must be known before the oil is placed into ser-
`vice. Therefore, during the oil refining process,
`the
`density of refined oil is first measured, and then, once
`known, is visibly marked on its container in terms of a
`range, e.g. 10W30, situated within a scale established by
`the American Petroleum Institute (API).
`Coriolis mass flow meters can be used to measure
`density of an unknown process fluid. In general, as
`taught, for example, in U.S. Pat. No. 4,491,025 (issued
`to J. E. Smith et. al. on Jan. 1, 1985), a Coriolis meter
`can contain two parallel conduits, each typically being
`a U-shaped flow tube. Each flow tube is driven such
`that it oscillates about an axis. As the process fluid flows
`through each oscillating flow tube, movement of the
`fluid produces reactionary Coriolis forces that are per-
`pendicularly oriented to both the velocity of the fluid
`and the angular velocity of tube. These reactionary
`Coriolis forces cause each tube to twist about a torsional
`axis that with U-shaped flow tubes is normal to its bind-
`ing axis. Both tubes are oppositely driven such that each
`tube behaves as a separate tine of a tuning fork and
`thereby advantageously cancels any undesirable Vibra-
`tions that might otherwise mask the Coriolis forces. The
`resonant frequency at which each flow tube oscillates
`depends upon its total mass, i.e. the mass of the empty
`tube itself plus the mass of the fluid flowing there-
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`29
`
`29
`
`

`
`4,872,351
`
`3
`rather small diameter. Consequently, if such a meter is
`used to measure the density of a fluid flowing through a
`rather large line, then the line is tapped and a small
`portion of the fluid in the line is diverted from the line,
`in what is commonly referred to as a “side stream”, and
`routed through the meter. Oftentimes, the fluid flowing
`in the side stream does not accurately represent the
`entire process fluid flowing through the line. For exam-
`ple, in certain applications, the process fluid may be a
`slurry containing relatively light liquid matter and rela-
`tively heavy solid matter. The solid matter, being
`denser than the liquid matter, will tend to flow along
`the bottom of the fluid stream with the liquid matter
`flowing immediately above. As a result, the side stream,
`depending where the line has been tapped along its
`cross-section, may contain a greater percentage of the
`liquid over the solid matter than that which occurs in
`the slurry that actually flows through the line. Some
`densimeter manufacturers claim that if the tap is taken
`along the middle of the line, then the density of the side
`stream will accurately represent the average density of
`the slurry hen flowing through the line. In practice, the
`actual percentage of solids that constitutes the slurry
`will dictate whether the density of the side stream,
`taken along the midpoint of the line, truly represents the
`density of the entire process fluid. Inasmuch as this
`percentage rarely equals 50%, this claim is generally
`not true. Consequently, in many applications, erroneous
`density measurements are produced by those meters
`that rely on measuring the density of the process fluid
`that flows in a side stream.
`
`4
`lating the percentage and volumetric measure of crude
`oil. Given the large quantities of crude oil that are usu-
`ally involved, any small inaccuracies in measuring den-
`sity can disadvantageously accumulate, over a rela-
`tively short interval of time, to a large error in a total-
`ized volumetric measure. Unfortunately, many pres-
`ently available densimeters do not provide a sufficiently
`accurate density reading, to one part in 10,000 as noted
`above, to yield a relatively large totalized volumetric
`measurement with an acceptably low error.
`Therefore, a need exists in the art for a densimeter
`which is accurate to at least one part in 10,000; which
`uses relatively inexpensive components; which substan-
`tially eliminates any error caused by changing charac-
`teristics of any of the electronic components; which
`provides easy conversion of density measurements from
`specific gravity units to any other unit, and which does
`not measure density using a side stream or require the
`use of a temperature controlled calibration fluid.
`
`SUMMARY OF THE INVENTION
`
`Accordingly, an object of the present invention is to
`provide an accurate densimeter.
`Another object is to provide such a densimeter which
`use relatively inexpensive components.
`A further object is to provide such a densimeter that
`is relatively insensitive to changing component charac-
`teristics, such as drift, aging, offset and the like.
`A further object is to provide such a densimeter that
`readily converts measured density readings into any
`other desired unit.
`
`A further object is to provide such a densimeter
`which does not measure density through a side stream.
`A further object
`is to provide such a densimeter
`which does not require the use of a temperature con-
`trolled calibration fluid.
`
`Lastly an additional object is to provide an accurate -'
`net oil computer.
`These and other objects are achieved in accordance
`with the principles of the present invention by a meter-
`ing system that employs a common Coriolis mass flow
`rate meter to implement both an accurate densimeter
`and a net oil computer. In essence, this apparatus mea-
`sures density of an unknown fluid by first determining
`the period at which one of two flow tubes contained
`within the Coriolis meter oscillates while the unknown
`fluid passes therethrough This apparatus then squares
`the result. Thereafter, the density of the unknown fluid
`is determined as a linear function of the squared tube
`period measurement for the unknown fluid, and squared
`tube period measurements and known density values for
`two known fluids, such as air and water, that have pre-
`viously and successively passed through the meter dur-
`ing calibration The inventive system advantageously
`functions as a net oil computer by obtaining mass flow
`and temperature measurements from the same flow
`tubes. By using the measured density and mass flow
`values of an oil-water emulsion that flows through the
`same Coriolis meter,
`the inventive system provides
`volumetric measurements of the flow rate and totalized
`flow of the entire emulsion and of the individual water
`and oil components present therein.
`In accordance with a- specific embodiment of the
`invention,
`the inventive metering system contains a
`mass flow rate circuit, a densimeter processor and a
`digital rate totalizer and display circuit (DRT). The
`mass flow rate circuit determines tho mass flow rate of
`a fluid as it passes through two parallel vibrating flow
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`Moreover, all densimeters need to be calibrated using
`a fluid (a calibration fluid) having a known density. This
`density is specified at a certain temperature. Unfortu-
`nately, the density of most fluids varies with tempera-
`ture: some fluids exhibit a significant variation, while 0
`other fluids exhibit relatively little variation. Conse-
`quently, many currently available densimeters require
`that the temperature of the calibration fluid must be
`carefully controlled before the fluid is injected into the
`densimeter for calibration. First, this necessitates that
`the container holding the fluid must be placed in a tem-
`perature bath for a sufficiently long period of time so
`that the fluid will stabilize to a desired temperature.
`Second, provisions must ba made to ensure that the
`temperature of the fluid will not change as the fluid is
`pumped through the meter. Accurately controlling the
`temperature of a fluid and then accurately maintaining
`its temperature, while the fluid is being pumped through
`the meter, is both a costly and tedious process.
`Furthermore, as one can appreciate, density measure-
`ments also find particular utility in ascertaining the
`percentage and volumetric measure of each of two
`immiscible substances flowing in a two component flow
`stream (emulsion). One common use involves determin-
`ing the amount of oil that occurs in an oil-water stream
`flowing through a pipeline. Specifically, saltwater often
`co-exists with crude oil in a common geologic forma-
`tion. As such, both substances are often pumped up
`together by a working oil well and simultaneously
`travel
`through piping to a downstream location at
`which the saltwater is ultimately separated from the
`crude oil. To accurately determine the amount of crude
`oil traveling through the pipe, well operators utilize a
`“net oil computer” to ascertain the amount of crude oil,
`on a percentage and volumetric basis of the total oil-
`water flow stream, that emanates from the well Net oil
`computers often utilize density measurements in calcu-
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`5
`tubes of the Coriolis meter. This circuit relies on using
`tube velocity information obtained from ferromagnetic
`velocity sensors attached to the tubes, and flow tube
`temperature obtained through a temperature sensor,
`such as an RTD, mounted to one of the flow tubes. The
`measured mass flow rate is provided as an output from
`the inventive system for connection to downstream
`process control equipment and is also applied, as an
`input, to the DRT.
`The densimeter processor, which is a microprocessor
`based system, determines the density of this fluid as it
`passes through the flow tubes. To do so, the densimeter
`processor processes velocity information provided by
`one of the ferromagnetic sensors to determine the per-
`iod at which the flow tubes vibrate. In addition, the
`densimeter processor has previously measured the tube
`periods and temperatures for two fluids, having known
`density values, that have successively passed through
`the flow tubes during meter calibration Based upon
`these past measurements obtained during calibration,
`the densimeter processor calculates density of the un-
`known fluid as a linear function relating the squared
`tube period measurement for the unknown fluid and the
`squared tube period measurements and known density
`values for the two known fluids. The assured density
`value is available as an output from the inventive system
`for connection to downstream process control equip-
`ment and, along with other parameters, is also serially
`supplied as an input to the DRT.
`In applications where the inventive system is used as
`a net oil computer, the unknown fluid is a crude oil-salt-
`water emulsion that flows through the meter. As such,
`the density of the unknown fluid is that of the emulsion.
`In order for the inventive system to provide separate
`volumetric flo