GB2062873A - Electrically operated monitoring device for detecting oil pollution - Google Patents

Electrically operated monitoring device for detecting oil pollution Download PDF

Info

Publication number
GB2062873A
GB2062873A GB7938308A GB7938308A GB2062873A GB 2062873 A GB2062873 A GB 2062873A GB 7938308 A GB7938308 A GB 7938308A GB 7938308 A GB7938308 A GB 7938308A GB 2062873 A GB2062873 A GB 2062873A
Authority
GB
United Kingdom
Prior art keywords
monitoring device
water
probe
probes
float
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.)
Withdrawn
Application number
GB7938308A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ILSLEY P
Original Assignee
ILSLEY P
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by ILSLEY P filed Critical ILSLEY P
Priority to GB7938308A priority Critical patent/GB2062873A/en
Publication of GB2062873A publication Critical patent/GB2062873A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/18—Water
    • G01N33/1886—Water using probes, e.g. submersible probes, buoys
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/18—Water
    • G01N33/1826—Organic contamination in water
    • G01N33/1833—Oil in water
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/06—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a liquid
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/20—Controlling water pollution; Waste water treatment

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Medicinal Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

An electrically operated monitoring device for monitoring the presence of oil pollution on the surface of a body of water, comprises a first probe (11), a second probe (12), an electrical detection circuit connected to the first and second probes, and a trigger circuit connected to the detection circuit and operable to trigger operation of an alarm and/or a surface oil recovery device when the detector circuit detects the presence of surface oil by virtue of a change in an electrical parameter e.g. resistance between said first and second probes. The probes are preferably arranged on a float (10) so that the first probe has contact with the liquid below the upper surface of the body of water and the second probe has contact with the liquid at the upper surface of the body of water. <IMAGE>

Description

SPECIFICATION Electrically operated monitoring device for detecting oil pollution This invention relates to an electrically operated monitoring device for monitoring the presence of oil pollution on the surface of a body of water.
As used in this specification, the term "a body of water" should include liquid mixtures composed mainly of water, but including liquid and/or solid pollutants, and including sewage effluent and industrial effluents.
Many different types of industrial process involve the use of very substantial volumes of water, and this water is often polluted by oil during the process, so that the polluted water has to be discharged to a lagoon or collecting tank at which the oil pollution has to be removed before the water can be re-used or discharged to a water course.
It is known to use so-called "oil recovery equipment" in order to remove oil pollution from the surface of a body of water, and this takes the many forms, including skimmers which attempt to skim-off the surface layer of oil, and surface-acting equipment using oleophilic separators which are moved along the polluted surface and attract the oil thereto.
One particularly efficient piece of surface acting equipment, as supplied by Oil Recovery International, uses a so-called "rope mop which is made of oleophilic material and is guided along an endless path in the polluted surface. The rope attracts oil pollution which aderes to the rope, and which is then removed from the rope, when the latter is out of the water and over a collecting tank, by passing the rope between rollers. The rope then returns to the polluted surface to carry out further oil recovery.
Whenever it is observed that a water surface e.g. of a lagoon is unduly polluted by oil, an operator starts-up the power for the rope mop, and keeps the rope mop operating until it is observed that the water surface has been cleaned to a satisfactory extent, when the power is switched-off by the operator.
Evidently, this requires an operator to keep a watch on the state of the surface of the lagoon (a) to determined when an oil recovery operation should be started-up and (b) to determine when the operation should be stopped. Since it would not be practical or economic for an operator to keep a permanent watch on the lagoon, it is possible, in some circumstances, for a large scale surface oil pollution to occur and to remain undetected for an excessive period before an oil recovery operation can be initiated.
Accordingly, in order to eliminate the human factor (both from a labour cost point of view, and also to avoid delays due to human error), there is a need to provide means for automatically monitoring the state of a water surface, and to trigger operation of an alarm and/or operation of an oil recovery system whenever surface oil pollution is detected.
According to the invention there is provided an electrically operated monitoring device for monitoring the presence of oil pollution on the surface of a body of water, said device comprising: a first probe; a second probe; an electrical detection circuit connected to said first and second probes; and a trigger circuit connected to said detection circuit and operable to trigger operation of an alarm and/or a surface oil recovery device when the detector circuit detects the presence of surface oil by virtue of a change in an electrical parameter between said first and second probes, the first probe being arranged in use to have contact with the liquid below the upper surface of the body of water and the second probe being arranged in use to have contact with the liquid at the upper surface of the body of water.
Preferably, the first and second probes are provided on a float which is so arranged that, in use, the first probe is located below the surface of the body of water and the second probe is located just at said surface. When there is substantially no surface oil pollution, the first and second probes will have contact with liquid having substantially similar electrical properties. However, when there is surface oil pollution, the second probe will have contact with liquid having different electrical properties from the liquid contacting with the first probe, and this will cause a change in an electrical parameter between the probes which is detected by the detector circuit to cause operation of the trigger circuit.
It is preferred that the change in electrical parameter which is detected by the detection circuit is a change in electrical resistance, and therefore electrical current, in the electrical circuit which is completed between the first and second probes within the body of water.
However, it should be understood that changes in other electrical parameters may be detected, if desired.
In order to control the positions of the probes relative to the surface of the body of water (so that the second probe can be located at or in the surface), it is preferred that a weight should be attached to the float in order to adjust the degree of immersion of the float. This weight may have to be varied in accordance with the nature of the "water" e.g. depending on the presence and nature of other pollutants in the water which may vary its overall density and therefore the height of the float.
In order to minimise the risk of faulty operation, it is preferred that a plurality of second probes is provided on the float, spaced apart around the periphery thereof, so that the float has a number of "sites" in the surface of the body of water, at which oil pollution can be monitored.
The preferred arrangement of the probes is on a float. However, it should be understood that other arrangements, including static arrangements, are possible if desired. Thus, by way of example, first and second probes could operate in conjunction with a sampling device which operates, continuously or intermittently, in order to expose the second probe to contact with liquid at the surface of the body of water and the first probe to contact with liquid other than that at the surface of the body of water.
In order to prevent premature operation of the monitoring device, e.g. due to pitching of the float by wind or the movement of the water (when the second probe(s) may be removed from the surface and exposed momentarily to contact with the atmosphere, or may dip below the surface of the water), it is preferred that a delay circuit is provided which only allows detection of the change in electrical parameter by the detection circuit when the change is maintained for a period greater than a given delay period as set by the delay circuit.
When the monitoring device operates in conjunction with surface oil recovery apparatus, the monitoring device will maintain automatically the apparatus in operation until there is no detectable surface oil pollution remaining. The monitoring device will then instruct switch-off of the apparatus. However, to avoid premature switch-off of the apparatus e.g. due to possible localised oil pollution removal in the region of the probes, it is preferred that the monitoring device includes a further delay circuit which is operable to maintain the operation of the alarm and/or the oil recovery apparatus for a predetermined period after the detection circuit indicates apparent removal of surface oil pollution. This predetermined period may be adjustable according to requirements, and may be, say, half an hour up to one hour, or may be adjustable up to ten hours.This can ensure that the oil recovery apparatus operates until substantially all of the surface oil pollution is removed from the body of water.
One embodiment of electrically operated monitoring device according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawing in which: Figure 1 is a schematic illustration of the monitoring device; and Figure 2 is a diagrammatic illustration of a surface oil monitoring arrangement for use in the monitoring device.
Referring now to the drawing, there is shown an electrically operated monitoring device for monitoring the presence of oil pollution on the surface of a body of water which comprises a float 10, a first probe 11 and a set of second probes 1 2 provided on the float 10, an electrical detection circuit connected to the first and second probes, and a trigger circuit connected to the detection circuit and operable to trigger operation of an alarm and/or a surface oil recovery device.
As shown in Fig. 2, the second probes 1 2 are located substantially at or in the surface of a body of water, whereas the first probe 11 is located at a lower level within the body of water. When there is substantially no surface oil pollution, the first probe 11 and the second probes 1 2 will each have contact with liquid having substantially the same electrical properties, and electrical circuits will be completed through the body of water between the second probes 1 2 and the first probe 11.
When there is surface oil pollution on the body of water, the second probes 1 2 will have contact with this oil, and therefore there will be a substantial change in an electrical parameter of the electrical circuit which is completed between the first and second probes.
The change in the electrical parameter between the first and second probes is detected by the detection circuit, so as to cause operation of the trigger circuit which operates an alarm and/or a surface oil recovery device.
In the illustrated embodiment, the electrical parameter, the change of which is monitored, comprises the electrical resistance between the first and second probes. The probes comprise electrodes which are connected to a transistorised relay which detects the change in resistance, by looking at the current flow, into a transistor base. Adjustments are supplied on the transistorised relay to compensate for the resistivity of the water in the range of 2 to 2000 Kohms (de-ionised water has a very high resistance, say up to 200K ohms, whereas dirty water has a resistance of less than 25K ohms.) The initial adjustments are necessary in order to compensate for different types of "water" which are to be treated.
Evidently, different types of polluted water will have different electrical properties, and the monitoring device will have to be set-up initially according to the operating environment.
Fig. 1 is a general layout of the monitoring device, comprising float 10, an amplifier 13, a first delay circuit 14 and a second delay circuit 15. The alarm which is triggered into operation by the monitoring device may comprise an audible or visual alarm, and the oil recovery system (alternatively or in addition) which may be triggered into operation by the monitoring device comprises any suitable surface oil recovery device.
In order to control the depth of immersion of the float 10 so that the second probes 1 2 can be located at or in the surface of the body of water, a weight 1 Q .s attached to the float 10. This weight 1 6 may have to be varied in accordance with the nature of the "water" e.g. depending on the presence and nature of other pollutants in the water which may vary its overall density and therefore the depth of immersion of the float.
The purpose of the first delay circuit 14 is to prevent premature operation of the monitoring device due to pitching of the float by wind or the movement of the water, when the second probes 1 2 may be removed from the surface and exposed momentarily to contact with the atmosphere, or may dip down below the surface into substantially oil-free regions of the body of water. The delay circuit only allows detection of the change in electrical parameter by the detection circuit when the change is maintained for a period greater than a given delay period as set by the delay circuit. This delay period may be set as small as three seconds, since the float has several second probes spaced apart around the centre line of the float.
The purpose of the second delay circuit 1 5 is to maintain the oil recovery device in operation for a predetermined period after the monitoring device has indicated that there is no detectable surface oil pollution. The reason for this is that, although the probes may indicate no detectable surface oil pollution in the region of the probes, possibly there may be further regions of the surface of the body of water which are still contaminated with oil, and the oil recovery device is therefore operated for a further period. This further period of operation may be set according to operating requirements, in which case the second delay circuit 1 5 will be adjusted to any desired predetermined period e.g. half an hour up to an hour, or adjustably up to ten hours.This is necessary because most recovery systems can clear a patch of oil before the entire surface of the body of water is completely clear.
Tests carried out with one embodiment of monitoring device according to the invention have detected the presence of surface oil pollution down to 1.5 parts per million.
Reverting to the first and second probes, these may be suitably positioned in many different ways, including the use of floating media such as commercial fishing floats or buoys. The second probes 1 2 are positioned around the central region of the float so as to be just in contact with the surface of the body of water. In this condition, an electrical current flows between the first and second probes when a voltage is applied, since water is capable of conducting electricity. However, when surface oil pollution occurs, the second probes 12 have contact with this oil, and the electrical current between the first and second probes is reduced, or interrupted. The reduction in electrical current is detected using a transistorised relay which detects the change in resistance by looking at the current flow into a transistor base. This system also applies to alternative deployment of probes/electrodes.
When a substantial volume of surface oil pollution occurs e.g. providing an oil surface layer of 5 mm, the second probes 1 2 rise up through this surface as shown in Fig. 2b.
While there have been described a first probe and at least one second probe provided on a float 10, it should be understood that the monitoring device may provide other arrangements for the probes. The only essential requirement is that the second probe should be exposed to contact with the liquid at the surface of the body of water, whereas the first probe is exposed to contact with liquid other than that at the surface of the body of water.
A sampling arrangement (not shown) operating continuously or intermittently, may be provided in order to supply appropriate portions of the liquid to the probes.

Claims (11)

1. An electrically operated monitoring device for monitoring the presence of oil pollution on the surface of a body of water, said device comprising: a first probe; a second probe; an electrical detection circuit connected to said first and second probes; and a trigger circuit connected to said detection circuit and operable to trigger operation of an alarm and/or a surface oil recovery device when the detector circuit detects the presence of surface oil by virtue of a change in an electrical parameter between said first and second probes, the first probe being arranged in use to have contact with the liquid below the upper surface of the body of water and the second probe being arranged in use to have contact with the liquid at the upper surface of the body of water.
2. A monitoring device according to claim 1, in which the first and second probes are provided on a float which is so arranged that, in use, the first probe is located below the surface of the body of water and the second probe is located just at said surface.
3. A monitoring device according to claim 2, in which a weight is attached to the float in order to adjust the degree of immersion of the float.
4. A monitoring device according to claim 2 or 3, including a plurality of second probes provided on said float, spaced apart around the periphery thereof.
5. A monitoring device according to any one of the preceding claims, in which the detection circuit is arranged to detect a change in electrical resistance, and therefore electrical current, in the electrical circuit which is completed between the first and second probes within the body of water.
6. A monitoring device according to claim 1, including a sampling device arranged to operate, continuously or intermittently, in order to expose the second probe to contact with liquid at the surface of the body of water and the first probe to contact with liquid other than that at the surface of the body of water.
7. A monitoring device according to any one of the preceding claims, including a delay circuit arranged to allow detection of the change in electrical parameter by the detection circuit only when the change is maintained for a period greater than a given delay period as set by the delay circuit.
8. A monitoring device according to any one of the preceding claims, and arranged to operate in conjunction with surface oil recovery apparatus so as to maintain automatically the apparatus in operation until there is no detectable surface oil pollution remaining.
9. A monitoring device according to claim 8, including a further delay circuit which is operable to maintain the operation of the alarm and/or the oil recovery apparatus for a predetermined period after the detection circuit indicates aparent removal of surface oil pollution.
1 0. A monitoring device according to claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawing.
11. Surface oil recovery apparatus provided with a monitoring device according to any one of the preceding claims.
GB7938308A 1979-11-06 1979-11-06 Electrically operated monitoring device for detecting oil pollution Withdrawn GB2062873A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB7938308A GB2062873A (en) 1979-11-06 1979-11-06 Electrically operated monitoring device for detecting oil pollution

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB7938308A GB2062873A (en) 1979-11-06 1979-11-06 Electrically operated monitoring device for detecting oil pollution

Publications (1)

Publication Number Publication Date
GB2062873A true GB2062873A (en) 1981-05-28

Family

ID=10508986

Family Applications (1)

Application Number Title Priority Date Filing Date
GB7938308A Withdrawn GB2062873A (en) 1979-11-06 1979-11-06 Electrically operated monitoring device for detecting oil pollution

Country Status (1)

Country Link
GB (1) GB2062873A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3127312A1 (en) * 1980-10-17 1982-05-13 Emhart Industries Inc., Farmington, Conn. SENSOR ARRANGEMENT

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3127312A1 (en) * 1980-10-17 1982-05-13 Emhart Industries Inc., Farmington, Conn. SENSOR ARRANGEMENT

Similar Documents

Publication Publication Date Title
ATE132623T1 (en) METHOD AND DEVICE FOR LINING OPEN POOLS CONTAINING LIQUID
BR9907347A (en) Method for detecting the condition of a fluid in a fluid system
US4583039A (en) Electrical testing device for insulating gloves
US5192932A (en) Sensing mat, and methods of constructing and utilizing same
KR840009136A (en) Method and apparatus for detecting and measuring particles in molten metal
GB2324374A (en) measuring residues present on the surface of circuit assemblies
GB2062873A (en) Electrically operated monitoring device for detecting oil pollution
US3800219A (en) Method and apparatus for detecting oil pollution in water
GB2245736B (en) Monitoring a bed underlying water
US4720669A (en) Geomembrane leak assessment shell shaped probe
ES2008052B3 (en) PROCEDURE AND APPARATUS FOR DETECTION OF MODIFICATIONS OF A SURFACE STATE AND CONTROL OF THIS
FR2682190B1 (en) METHOD FOR THE SELECTIVE DETECTION OF A RESISTANT FAULT IN AN ELECTRICAL POWER DISTRIBUTION NETWORK AND DEVICE FOR ITS IMPLEMENTATION.
KR890015811A (en) Electrolytic finishing process
JPH09210836A (en) Water shielding sheet and laying structure of its protective member
JP2000088691A (en) Apparatus and method for measurement of leak of water
SE8106028L (en) DEVICE FOR THE DETECTION OF A SUBSTANCE ON A WASHER
JP3192101B2 (en) Water level detection method in the water tank
JPH10312723A (en) Salt contamination predicting apparatus for insulator
JPS6034066B2 (en) Magnetic particle testing equipment
EP1446646A1 (en) A liquid leak multi-layer detector
KR0134926Y1 (en) Alarmer for preventing pollution of water
FR2606153B1 (en) METHOD AND DEVICE FOR DETECTING THE NATURE OF A MEAT MEDIUM
JPS56152537A (en) Liquid level monitor for electric discharge machining device
TWM623746U (en) Sludge scraper including scraping board debug device
DE4410953A1 (en) Conductivity sensor

Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)