CA1183019A - Oil detector - Google Patents
Oil detectorInfo
- Publication number
- CA1183019A CA1183019A CA000401768A CA401768A CA1183019A CA 1183019 A CA1183019 A CA 1183019A CA 000401768 A CA000401768 A CA 000401768A CA 401768 A CA401768 A CA 401768A CA 1183019 A CA1183019 A CA 1183019A
- Authority
- CA
- Canada
- Prior art keywords
- oil
- light source
- pulsed
- scatter
- pulsed light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 19
- 230000001360 synchronised effect Effects 0.000 claims description 10
- 239000000203 mixture Substances 0.000 claims description 4
- 239000003921 oil Substances 0.000 abstract description 48
- 238000000034 method Methods 0.000 description 8
- 238000005259 measurement Methods 0.000 description 6
- 238000000149 argon plasma sintering Methods 0.000 description 3
- 239000010762 marine fuel oil Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 101710170231 Antimicrobial peptide 2 Proteins 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000002283 diesel fuel Substances 0.000 description 2
- 230000009977 dual effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 101710170230 Antimicrobial peptide 1 Proteins 0.000 description 1
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/47—Scattering, i.e. diffuse reflection
- G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
- G01N21/53—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke
- G01N21/532—Scattering, i.e. diffuse reflection within a body or fluid within a flowing fluid, e.g. smoke with measurement of scattering and transmission
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
OIL DETECTOR
ABSTRACT OF THE DISCLOSURE
An oil in water detector arrangement wherein the response signal is substantially independent of oil type.
Scattered light signals for an incident beam directed into a scatter cell are measured at two scatter angles (21, 22) and a corrected oil level value is calculated from the difference between the two signals. This obviates the need for recalibration of the arrangement for different oils.
ABSTRACT OF THE DISCLOSURE
An oil in water detector arrangement wherein the response signal is substantially independent of oil type.
Scattered light signals for an incident beam directed into a scatter cell are measured at two scatter angles (21, 22) and a corrected oil level value is calculated from the difference between the two signals. This obviates the need for recalibration of the arrangement for different oils.
Description
BACKGROVND OF THE INVENTION
This invention relates -to the detection of oil in water and in particular to arrangem~nts for detec-ting and measuring the concentrations of different -types of oils in water. Typically, these arranyemen-ts are used in ba]last and bilge monitoring operations on ocean golng -tankers and/or other vessels.
One of the problems in oil-in-water detection and measurement by a light scattering technique results from widely differing responses from different oils that must be measured~ Not only should the detector employed be able to distinguish between suspended solid particles and oil droplets, but it also should be able to compensate for the response speeds of different types of oils. Hitherto this has not been possible~
The intensity of light scattered by a suspension of oil-in-water is a function of the scattering angle and has a maximum value at an angle de-termined primarily by the averaye size of the oil droplets. The droplet size is, in turn, det-ermined by the oil viscosity. The viscosity range of both cr~d,e and refined oils is, of course, very wide. They are also temperature dependerlt. This makes it necessary to recal-ibrate when a single scatter angle cell is employed to measure different types of oil or to measure the same oil a~ widely differing temperatures.
G.D. Pitt 24, U.S. Patent No. 4,265,535 issued May 5, 1981, describes a dual angle scatter cell in which the light scattering ang].es are such that the effects of suspended solid scatter can be reduced from the oil reading.
..
G. D. Pitt et al. 3~-S-lX
SUMMARY OF THE PRESENT INVENTIO~
In accordance with ~he o.il detector of the present invention, there is provided an oil-in-water detector arrangement compr.ising: a scatter cell; a pulsed light source, scattering of light from said pulsed light source being e~ected; drive means for said pulsed l.ight source; a first photodetector disposed in alignment w;th said pulsed light source so as to receive light ~ransmitted directly through ~he oil and water mixture: second and thircl photodetector6 dispos0d respectively at first and second angles to said incident liyht beam~ said incident light beam being generated by said pulsed light source so as to receive light scattered by the oil and water mixture; first, second and third amplifier channels having first, second and third synchronou6 detecto.rs, respectively, associated with said first, second and third pAotodetectors, respectively, and, in use, enabled when said pulsed li.ght source is pulsed by said drive means; gain control means including a feedback loop from said first synchronous datector via an associated amplifier channel to said drive means, control of said pulsed light source intensity being provided by said feedback loop; and means responsive to the difference between the outputs oE said second and third amplifier channels for producing an indication of oil concentration.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings which illustrate exemplary embodiments of the present invention:
Fig. 1 is a diagrammatic view of an oil-in-water detector constructed in accordance with the presen~
invention;
Fig. 2 is a diagrammatic view of circuitry for the detector of Fig. 1:
Fig. 3 is a diagrammatic view alternative to that of Fig. 2; and Figs. 4 and 5 are graphs of the responses of the circuits of Figs. 2 and 3, respectively, ~o various types of oil.
-3- G.D. Pitt: et aL. 3~-5-1 DESCRIPTION OF THE PREFERRED EMBODIMBNTS
. . .
Referring to Fig. 1, the scatter cell of the present invention comprises a housing lL through which water c~rrying suspended oil may flow. Housing 11 is provided with an inlet window 12 for incident light and a plurali-ty of outlet windows 13, 14 and 118 for receivinq light scattered from the suspended oil. Typically, the incident liyht bearn is provided via an infra~red solid state laser (not shown), but a ZED or other light source may also be used.
A baffle 15a may be mounted adjacent the window 12 to ensure that only scattered light reaches the windows 13 and 14.
In some applications the baffle may be mounted perpendicular to the incident ligh~ beam as indicated by the reference 15b.
Scattered light reaching the windows 13 and 14 is fed to respective photodetectors 16 and 17, preferably via optical fibers 18. Advantageously the scatter cell also includes a further output window 118 whereby the intensity of the incident beam may be monitored. Compensation for changes in that intensity may then ~e made.
The outputs of the photodetectors 16 and 17 are coupled to electronic circuitry~ e.g., a microprocessor 19, which is programmed to compute an oil concentration level from the absolute and relative values of the outputs of photodetectors 16 and 17.
In accordance with the present invention, it has been found that the angle at which light is scattered from oil droplets suspended in water and the scattered light intensity depend primarily on the average droplet diameter and refractive index. This, in turn, is determined by the oil viscosity.
Thus, for exampler diesel oil which is relatively light produces small droplets which scatter light through a relatively large angle, whereas a more viscous medium fuel oil produces larger droplets which scatter light predominantly through a relatively small angle. Thus, each oil produces its own characteristic scattering intensity at each of the photodetectors 16 and 17, -~- G.D. Pitt et al. 34~5~LX
and by comparing these two intensities, a measure oE the oil concentration can be obtained~ This technique also provides compensation for the lowee intensity of llght scattered by more viscous oil~.
The difference in scattering response characteristics of different types oE oils is illustrated in the fo]lowing example~
Water containing an injected 100 parts per million of diesel oil or medium fuel oil (MFO) was passed throuyh a ce]l of the type shown with windows 14 and 13 disposed, respectively, lQ at 17, 30 and 38 to an incident gallium arsenide infra-red light source. Photodetector outputs monitored for each type of oil might result as follows (in arbitrary units).
Detector Response Oil Type/Angle 17 30o 38 -Diesel 118118 17 From the above it will be clear that by suitable programming of the circuitry coupled to the photodetectors (photocells), an absolute concentration value for each type of oil can be obtained without individual calibration of the system.
By performing subtractions or ratioing of the light scatter signals at the various scatter angles, the concentration of each individual oil can be obtained. Thus, the detector system requires only a single initial calibration and can then be used on all types of oil without further adjustment.
Cells with perpendicularly mounted baffle l5a can be constructed having scattering angles al and ~2 of 22.5 and 45, respectively, and will be found to give good results with a wide range of oils. Typicallyl scattering angles ~1 and a2 of 20 to 25 and 40 to 50, respectively, are preferred. These scattering angles are given by way o example and are not to be regarded as limiting.
-5- G.D. Pitt et al. 34-5-LX
A square or rectangular ceLl could be used. Such geometries allow for an array of detectors mounted opposite the source on a flat printed circuit board. Other cell cross sections can also be used.
Referring now to Fig. 2, this shows a typical clrcuit arrangement for calculating oil concentration levels from the outputs of the dual angle cell arrangement of E'ig. 1. The cell outputs for scattering angles of zero, ~1 and a2 are fed via photodiode detectors D0, ~1 and D2 to preamplifiers PA0, PAl and PA2. These preamplifiers may each include a Eield efEect transistor or an operational amplifier.
The outputs of the preampliflers PA0, P~l and PA2 are fed via amplifiers AMP0, AMPl and AMP2 to respective synchronous detectors SD0, SDl and SD2.
Light is injected into the scatter cell via a laser or an LED 21 driven in a pulsed mode by driver circuit LDl.
Typically, the light source 21 is operated at a low duty cycle, for example 2%, thus ensuring that the source has an extended lifetime. The driver circuit LDl is coupled to the synchronous detectors SD0, SDl and 5D2 such that the detectors are enabled only when the light source 21 is pulsed on.
The output from the synchronous detector SD0 associated with the direct light path through the cell is fed back to the drive circuit LDl so as to provide an automatic gain control feedback loop whereby compensation is provided both from aging or drift of the light source and from oil fouling of the cell.
This technique ensures that continuous calibration of the detector arrangement is effected.
The outputs of synchronous detectors SDl and 5D2 associated with the scattered light signals are fed to the respective inputs of a differential amplifier DAl whose output comprises an analog signal corresponding to the difference in intehsity between the two scattered light signals. Although oil viscosity has a significant effect on the scatter profile of an incident light beam, we have found that the difference signal obtained from scatter signals received at two suitable angles to an incident light beam is substantially independent of oiL types.
-6 G.D. Pitt et al. 34-5-lX
Typically, the differential amplifier output signal is fed via a buffer stage BSl to a control and displa~i~ arrangement CDl which may include means for recording measured oil levels and for generating a warning signal when a predetermlned oil leve] is exceeded.
The circuit arrangement shown in Fig. 3 is some~hat similar to that of Fig. 2 but employs digital processing techniques. The input circuit stages comprising preamplifiers PA0, PAl and PA2, amplifiers AMP0, AMP1 and AMP2 and synchronous detectors SD0, SDl and SD2 operate in a similar manner to the arrangement of Fig. 2 and need not be further described.
The outputs of the synchronous detectors SD0~ SDl and SD2 are fed via an analog multiplexer to an analog to digital converter A/~l and a microprocessor MPUl programmed to perform the computation of oil concentrations from the digitized detector output signals. The microprocessor output may be used to drive a variety of operating functions including cell flushing and water sampling. The microprocessor can also drive an output recorder and an excess oil alarm syste~.
Typically, the microprocessor is programmed with an algorithm constructed~ e.g., to compensate for droplet-size variations in the fluid flow through the cell or to provide outputs giving an indication of droplet size distribution.
In an alternative embodiment a single synchronous detector preceded by a multiplexer may be employed. The single detector then feeds into an analog to digital converter.
In further applications light scattering may be effected at three or more angles to the incident beam to provide further accuracy in the measurement process.
Fig. 4 illustrates the results obtained from the measurement of various types of oil using the circuits of Figs. 2 and 3. Fig. 5~ which is included for comparison purposes, illustrates the corresponding measurements obtained from a conventional single angle scatter cell. In each case measured quantities of each type of oil were injected into a ~7- G.D~ Pitt et a]. 34-5-lX
water stream flowing through the cell and the correspondlng detector output response was determined. As can be seen from Figs. 4 and 5, the response spread from the various types of oils at an injected level oE 100 parts per million is ~ 27% for a single angle scatter cell ~Fig. S) but this spread is reduced to within _ 20% (Fig. 4) by using the double angle scatter techniques described herein. This represents a s:igniEicant improvement in accuracy over conventional techniques described herein suitable for bilge water monitoring applications without the need for recalibration for different oilsu The algcrithms necessary for the computation process can also be partially dealt with using set gains at different angles on the amplifiers, the ratios/values of these present gains being optimized in prior experiments and tests. This opens up the use of such equipment for generalized measurements on 3 phase systems - e.g. for measuring oil/particles/water etc., and filtering checking systems.
Typically, the algorithm for a particular cell geometry is determined for measurements on known injected oil levels, the ~0 necessary techniques being known to those skilled in the art.
Once a particular scatter cell has been calibrated in this way no further calibration is necessary.
This invention relates -to the detection of oil in water and in particular to arrangem~nts for detec-ting and measuring the concentrations of different -types of oils in water. Typically, these arranyemen-ts are used in ba]last and bilge monitoring operations on ocean golng -tankers and/or other vessels.
One of the problems in oil-in-water detection and measurement by a light scattering technique results from widely differing responses from different oils that must be measured~ Not only should the detector employed be able to distinguish between suspended solid particles and oil droplets, but it also should be able to compensate for the response speeds of different types of oils. Hitherto this has not been possible~
The intensity of light scattered by a suspension of oil-in-water is a function of the scattering angle and has a maximum value at an angle de-termined primarily by the averaye size of the oil droplets. The droplet size is, in turn, det-ermined by the oil viscosity. The viscosity range of both cr~d,e and refined oils is, of course, very wide. They are also temperature dependerlt. This makes it necessary to recal-ibrate when a single scatter angle cell is employed to measure different types of oil or to measure the same oil a~ widely differing temperatures.
G.D. Pitt 24, U.S. Patent No. 4,265,535 issued May 5, 1981, describes a dual angle scatter cell in which the light scattering ang].es are such that the effects of suspended solid scatter can be reduced from the oil reading.
..
G. D. Pitt et al. 3~-S-lX
SUMMARY OF THE PRESENT INVENTIO~
In accordance with ~he o.il detector of the present invention, there is provided an oil-in-water detector arrangement compr.ising: a scatter cell; a pulsed light source, scattering of light from said pulsed light source being e~ected; drive means for said pulsed l.ight source; a first photodetector disposed in alignment w;th said pulsed light source so as to receive light ~ransmitted directly through ~he oil and water mixture: second and thircl photodetector6 dispos0d respectively at first and second angles to said incident liyht beam~ said incident light beam being generated by said pulsed light source so as to receive light scattered by the oil and water mixture; first, second and third amplifier channels having first, second and third synchronou6 detecto.rs, respectively, associated with said first, second and third pAotodetectors, respectively, and, in use, enabled when said pulsed li.ght source is pulsed by said drive means; gain control means including a feedback loop from said first synchronous datector via an associated amplifier channel to said drive means, control of said pulsed light source intensity being provided by said feedback loop; and means responsive to the difference between the outputs oE said second and third amplifier channels for producing an indication of oil concentration.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings which illustrate exemplary embodiments of the present invention:
Fig. 1 is a diagrammatic view of an oil-in-water detector constructed in accordance with the presen~
invention;
Fig. 2 is a diagrammatic view of circuitry for the detector of Fig. 1:
Fig. 3 is a diagrammatic view alternative to that of Fig. 2; and Figs. 4 and 5 are graphs of the responses of the circuits of Figs. 2 and 3, respectively, ~o various types of oil.
-3- G.D. Pitt: et aL. 3~-5-1 DESCRIPTION OF THE PREFERRED EMBODIMBNTS
. . .
Referring to Fig. 1, the scatter cell of the present invention comprises a housing lL through which water c~rrying suspended oil may flow. Housing 11 is provided with an inlet window 12 for incident light and a plurali-ty of outlet windows 13, 14 and 118 for receivinq light scattered from the suspended oil. Typically, the incident liyht bearn is provided via an infra~red solid state laser (not shown), but a ZED or other light source may also be used.
A baffle 15a may be mounted adjacent the window 12 to ensure that only scattered light reaches the windows 13 and 14.
In some applications the baffle may be mounted perpendicular to the incident ligh~ beam as indicated by the reference 15b.
Scattered light reaching the windows 13 and 14 is fed to respective photodetectors 16 and 17, preferably via optical fibers 18. Advantageously the scatter cell also includes a further output window 118 whereby the intensity of the incident beam may be monitored. Compensation for changes in that intensity may then ~e made.
The outputs of the photodetectors 16 and 17 are coupled to electronic circuitry~ e.g., a microprocessor 19, which is programmed to compute an oil concentration level from the absolute and relative values of the outputs of photodetectors 16 and 17.
In accordance with the present invention, it has been found that the angle at which light is scattered from oil droplets suspended in water and the scattered light intensity depend primarily on the average droplet diameter and refractive index. This, in turn, is determined by the oil viscosity.
Thus, for exampler diesel oil which is relatively light produces small droplets which scatter light through a relatively large angle, whereas a more viscous medium fuel oil produces larger droplets which scatter light predominantly through a relatively small angle. Thus, each oil produces its own characteristic scattering intensity at each of the photodetectors 16 and 17, -~- G.D. Pitt et al. 34~5~LX
and by comparing these two intensities, a measure oE the oil concentration can be obtained~ This technique also provides compensation for the lowee intensity of llght scattered by more viscous oil~.
The difference in scattering response characteristics of different types oE oils is illustrated in the fo]lowing example~
Water containing an injected 100 parts per million of diesel oil or medium fuel oil (MFO) was passed throuyh a ce]l of the type shown with windows 14 and 13 disposed, respectively, lQ at 17, 30 and 38 to an incident gallium arsenide infra-red light source. Photodetector outputs monitored for each type of oil might result as follows (in arbitrary units).
Detector Response Oil Type/Angle 17 30o 38 -Diesel 118118 17 From the above it will be clear that by suitable programming of the circuitry coupled to the photodetectors (photocells), an absolute concentration value for each type of oil can be obtained without individual calibration of the system.
By performing subtractions or ratioing of the light scatter signals at the various scatter angles, the concentration of each individual oil can be obtained. Thus, the detector system requires only a single initial calibration and can then be used on all types of oil without further adjustment.
Cells with perpendicularly mounted baffle l5a can be constructed having scattering angles al and ~2 of 22.5 and 45, respectively, and will be found to give good results with a wide range of oils. Typicallyl scattering angles ~1 and a2 of 20 to 25 and 40 to 50, respectively, are preferred. These scattering angles are given by way o example and are not to be regarded as limiting.
-5- G.D. Pitt et al. 34-5-LX
A square or rectangular ceLl could be used. Such geometries allow for an array of detectors mounted opposite the source on a flat printed circuit board. Other cell cross sections can also be used.
Referring now to Fig. 2, this shows a typical clrcuit arrangement for calculating oil concentration levels from the outputs of the dual angle cell arrangement of E'ig. 1. The cell outputs for scattering angles of zero, ~1 and a2 are fed via photodiode detectors D0, ~1 and D2 to preamplifiers PA0, PAl and PA2. These preamplifiers may each include a Eield efEect transistor or an operational amplifier.
The outputs of the preampliflers PA0, P~l and PA2 are fed via amplifiers AMP0, AMPl and AMP2 to respective synchronous detectors SD0, SDl and SD2.
Light is injected into the scatter cell via a laser or an LED 21 driven in a pulsed mode by driver circuit LDl.
Typically, the light source 21 is operated at a low duty cycle, for example 2%, thus ensuring that the source has an extended lifetime. The driver circuit LDl is coupled to the synchronous detectors SD0, SDl and 5D2 such that the detectors are enabled only when the light source 21 is pulsed on.
The output from the synchronous detector SD0 associated with the direct light path through the cell is fed back to the drive circuit LDl so as to provide an automatic gain control feedback loop whereby compensation is provided both from aging or drift of the light source and from oil fouling of the cell.
This technique ensures that continuous calibration of the detector arrangement is effected.
The outputs of synchronous detectors SDl and 5D2 associated with the scattered light signals are fed to the respective inputs of a differential amplifier DAl whose output comprises an analog signal corresponding to the difference in intehsity between the two scattered light signals. Although oil viscosity has a significant effect on the scatter profile of an incident light beam, we have found that the difference signal obtained from scatter signals received at two suitable angles to an incident light beam is substantially independent of oiL types.
-6 G.D. Pitt et al. 34-5-lX
Typically, the differential amplifier output signal is fed via a buffer stage BSl to a control and displa~i~ arrangement CDl which may include means for recording measured oil levels and for generating a warning signal when a predetermlned oil leve] is exceeded.
The circuit arrangement shown in Fig. 3 is some~hat similar to that of Fig. 2 but employs digital processing techniques. The input circuit stages comprising preamplifiers PA0, PAl and PA2, amplifiers AMP0, AMP1 and AMP2 and synchronous detectors SD0, SDl and SD2 operate in a similar manner to the arrangement of Fig. 2 and need not be further described.
The outputs of the synchronous detectors SD0~ SDl and SD2 are fed via an analog multiplexer to an analog to digital converter A/~l and a microprocessor MPUl programmed to perform the computation of oil concentrations from the digitized detector output signals. The microprocessor output may be used to drive a variety of operating functions including cell flushing and water sampling. The microprocessor can also drive an output recorder and an excess oil alarm syste~.
Typically, the microprocessor is programmed with an algorithm constructed~ e.g., to compensate for droplet-size variations in the fluid flow through the cell or to provide outputs giving an indication of droplet size distribution.
In an alternative embodiment a single synchronous detector preceded by a multiplexer may be employed. The single detector then feeds into an analog to digital converter.
In further applications light scattering may be effected at three or more angles to the incident beam to provide further accuracy in the measurement process.
Fig. 4 illustrates the results obtained from the measurement of various types of oil using the circuits of Figs. 2 and 3. Fig. 5~ which is included for comparison purposes, illustrates the corresponding measurements obtained from a conventional single angle scatter cell. In each case measured quantities of each type of oil were injected into a ~7- G.D~ Pitt et a]. 34-5-lX
water stream flowing through the cell and the correspondlng detector output response was determined. As can be seen from Figs. 4 and 5, the response spread from the various types of oils at an injected level oE 100 parts per million is ~ 27% for a single angle scatter cell ~Fig. S) but this spread is reduced to within _ 20% (Fig. 4) by using the double angle scatter techniques described herein. This represents a s:igniEicant improvement in accuracy over conventional techniques described herein suitable for bilge water monitoring applications without the need for recalibration for different oilsu The algcrithms necessary for the computation process can also be partially dealt with using set gains at different angles on the amplifiers, the ratios/values of these present gains being optimized in prior experiments and tests. This opens up the use of such equipment for generalized measurements on 3 phase systems - e.g. for measuring oil/particles/water etc., and filtering checking systems.
Typically, the algorithm for a particular cell geometry is determined for measurements on known injected oil levels, the ~0 necessary techniques being known to those skilled in the art.
Once a particular scatter cell has been calibrated in this way no further calibration is necessary.
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINES AS FOLLOWS:
1. An oil-in-water detector arrangement comprising: a scatter cell: a pulsed light source, scattering of light from said pulsed light source being effected drive means for said pulsed light source: a first photodetector disposed in alignment with said pulsed light source so as to receive light transmitted directly through the oil and water mixture: second and third photodetectors disposed respectively at first and second angles to said incident light beam, said incident light beam being generated by said pulsed light source so as to receive light scattered by the oil and water mixture: first, second and third amplifier channels having first, second and third synchronous detectors, respectively, associated with said first, second and third photodetectors, respectively, and, in use, enabled when said pulsed light source is pulsed by said drive means; gain control means including a feedback loop from said first synchronous detector via an associated amplifier channel to said drive means, control of said pulsed light source intensity being provided by said feedback loop; and means responsive to the difference between the outputs of said second and third amplifier channels for producing an indication of oil concentration.
2. An arrangement as claimed in claim 1, wherein said second photodetector is disposed at a scatter angle of between about 20° to 25° and said third photodetector at an angle of between about 40° to 50° to the incident light beam.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8113073 | 1981-04-28 | ||
| GB8113073 | 1981-04-28 | ||
| GB8206027 | 1982-03-02 | ||
| GB8206027A GB2097529B (en) | 1981-04-28 | 1982-03-02 | Detecting oil in water |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1183019A true CA1183019A (en) | 1985-02-26 |
Family
ID=26279269
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000401768A Expired CA1183019A (en) | 1981-04-28 | 1982-04-27 | Oil detector |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1183019A (en) |
| DE (1) | DE3212734C2 (en) |
| GB (1) | GB2097529B (en) |
| NL (1) | NL8201736A (en) |
Families Citing this family (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE453015B (en) * | 1981-11-25 | 1988-01-04 | Bergstrom Per Hakan Sture | METHOD DEVICE FOR Saturation of the concentration of particles transported by a liquid through a tube |
| SE453016B (en) * | 1981-11-25 | 1988-01-04 | Bergstrom Per Hakan Sture | METHOD FOR SATURING THE CONCENTRATION OF PARTICLES TRANSPORTED BY A FLUID THROUGH A PIPE |
| NL8301701A (en) * | 1983-05-11 | 1984-12-03 | Ihc Holland Nv | SYSTEM AND DEVICE FOR DETECTING DEPOT FORMATION. |
| DE3319922A1 (en) * | 1983-06-01 | 1984-12-06 | Bayer Ag, 5090 Leverkusen | Method and device for controlling processes in which a disperse phase is involved |
| GB2141553B (en) * | 1983-06-14 | 1987-06-03 | Standard Telephones Cables Ltd | Scatter cells for photo sensors |
| US4677298A (en) * | 1983-12-13 | 1987-06-30 | Kollmorgen Technologies Corporation | Method of monitoring ink-water balance on a lithographic printing press |
| GB2166234B (en) * | 1984-10-27 | 1987-12-31 | Stc Plc | Detecting oil in water |
| SE450791B (en) * | 1985-11-19 | 1987-07-27 | Salen & Wicander Ab | SET AND DEVICE FOR DETECTING THE POLLUTION CONTENT IN A FLUID |
| DE3627199A1 (en) * | 1986-08-11 | 1988-02-25 | Henkel Kgaa | METHOD FOR CONTROLLING THE CLEAVING OF OIL / WATER EMULSIONS |
| DE3813718A1 (en) * | 1988-04-22 | 1989-11-02 | Max Planck Gesellschaft | Multi-angle light scattering |
| DE3938142A1 (en) * | 1989-11-16 | 1991-05-29 | Mak Maschinenbau Krupp | METHOD AND DEVICE FOR QUALITATIVE AND QUANTITATIVE DETERMINATION OF INGREDIENTS |
| US5140168A (en) * | 1990-12-03 | 1992-08-18 | Great Lakes Instruments, Inc. | Turbidimeter signal processing circuit using alternating light sources |
| DE4233220A1 (en) * | 1992-10-02 | 1994-04-07 | Conducta Endress & Hauser | Method and device for measuring turbidity in aqueous media |
| GB2272513B (en) * | 1992-11-05 | 1997-05-07 | Apv Rosista Ltd | Adjusting filter aid in response to solid particle compensation |
| FI97083C (en) * | 1993-12-31 | 1996-10-10 | Neste Oy | Method and apparatus for determining the stability of the oil |
| EP0707247B1 (en) * | 1994-10-11 | 2007-02-07 | Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co.KG. | Analyzer, in particular for waste water |
| US5601080A (en) * | 1994-12-28 | 1997-02-11 | Coretech Medical Technologies Corporation | Spectrophotometric blood analysis |
| GB2299161A (en) * | 1995-03-24 | 1996-09-25 | Alan Philip Roper | Electronic digital control unit for measuring pollution levels in liquids |
| GB2371858B (en) * | 2001-02-05 | 2004-10-13 | Abb Offshore Systems Ltd | Monitoring particles in a fluid flow |
| DE10105793B4 (en) * | 2001-02-07 | 2010-03-04 | Iav Gmbh Ingenieurgesellschaft Auto Und Verkehr | Method for evaluating lubricant quality |
| CN110618109A (en) * | 2019-10-31 | 2019-12-27 | 中国科学院长春光学精密机械与物理研究所 | Device for calibrating and measuring impurity particles and free water in liquid oil |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3510666A (en) * | 1967-05-05 | 1970-05-05 | Bowser Inc | Turbidity meter having calibrating light source |
| US3872315A (en) * | 1973-12-21 | 1975-03-18 | Babcock & Wilcox Co | Radiation sensitive fluid analyzer |
| SE387172B (en) * | 1974-08-28 | 1976-08-30 | Svenska Traeforskningsinst | DEVICE FOR SATURING THE CONTENT IN A FLOWING LIQUID EXISTING SUBSTANTIZED SUBJECT |
| GB1556029A (en) * | 1976-10-29 | 1979-11-14 | Standard Telephones Cables Ltd | Oil in water detection |
| GB1602969A (en) * | 1977-08-26 | 1981-11-18 | Standard Telephones Cables Ltd | Oil-in-water detection system |
| GB1588862A (en) * | 1978-05-11 | 1981-04-29 | Standard Telephones Cables Ltd | Measuring oil in water |
-
1982
- 1982-03-02 GB GB8206027A patent/GB2097529B/en not_active Expired
- 1982-04-06 DE DE19823212734 patent/DE3212734C2/en not_active Expired - Fee Related
- 1982-04-27 NL NL8201736A patent/NL8201736A/en not_active Application Discontinuation
- 1982-04-27 CA CA000401768A patent/CA1183019A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3212734C2 (en) | 1994-04-07 |
| NL8201736A (en) | 1982-11-16 |
| GB2097529A (en) | 1982-11-03 |
| DE3212734A1 (en) | 1983-01-13 |
| GB2097529B (en) | 1984-09-19 |
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