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EP0247120A1 - Assessing contamination of liquids - Google Patents

Assessing contamination of liquids

Info

Publication number
EP0247120A1
EP0247120A1 EP19860906891 EP86906891A EP0247120A1 EP 0247120 A1 EP0247120 A1 EP 0247120A1 EP 19860906891 EP19860906891 EP 19860906891 EP 86906891 A EP86906891 A EP 86906891A EP 0247120 A1 EP0247120 A1 EP 0247120A1
Authority
EP
European Patent Office
Prior art keywords
groove
plate
sample
liquid
channel
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Withdrawn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
EP19860906891
Other languages
German (de)
French (fr)
Inventor
Peter J. Field House WILSON
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.)
Fawcett Engineering Ltd
Original Assignee
Fawcett Engineering Ltd
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 Fawcett Engineering Ltd filed Critical Fawcett Engineering Ltd
Publication of EP0247120A1 publication Critical patent/EP0247120A1/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Withdrawn legal-status Critical Current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
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/06—Investigating concentration of particle suspensions
    • G01N15/0656—Investigating concentration of particle suspensions using electric, e.g. electrostatic methods or magnetic methods

Definitions

  • the present invention relates to a method and apparatus for assessing the nature and degree of contamination of liquids. It is especially useful for examining lubricating oils with a proportion of metallic contamination.
  • a known method of assessing contamination in lubricating oils uses a plane glass plate. A sample of oil is run down the plate while being subjected to a magnetic force from an electromagnet beneath the plate. The magnetic force pulls down ferromagnetic contaminating particles which are deposited on the plate.
  • the deposited particles are then viewed under red or green light to check the constitution of the contamination.
  • the deposits are photographed for comparison with other photographs of specimen deposits from oil for which the constitution of the contaminating particles is known.
  • the plates are quite large giving a trace about 20 cm long. The liquid spreads out as it runs down yielding a thin widely-spread deposit. A strong magnetic field is needed for it to affect the sample through the glass plate.
  • the present invention provides a method of assessing contamination in a sample of liquid comprising supplying a liquid sample to a channel and causing the sample to flow along the channel in a magnetic field so that contaminating particles are deposited in the channel.
  • the method provides a convenient way of assessing the nature and degree of contamination of liquids. Where necessary the liquids may first be mixed with a solvent to decrease its viscosity. The method produces a deposit of contaminating particles in the bottom of the channel, this deposit can be inspected under normal lighting and may be compared with other examples of deposition patterns.
  • the present invention provides in a second aspect apparatus for assessing contamination in a sample of liquid comprising a channel along which a sample of liquid can flow and means for providing a magnetic field in the path of the sample so that contaminating material is deposited in the channel.
  • the apparatus may also include a means for supplying a sample of viscous liquid to the channel.
  • the channel protects the deposited material so that residual liquid in the channel may be washed away with solvent.
  • a channel with deposit can also be stored for later comparison with samples.
  • a preferred form of channel is formed by a plate having a straight groove extending to or towards at least one edge of the plate, the walls of the groove having a smooth finish, the plate being of effectively homogeneous material such as plastics material.
  • the channel provides a perdetermined path for a sample to flow along.
  • the channel helps to confine the sample to the path. By thus restricting the spread of liquid the deposit is concentrated in the channel and the trace of deposit is easier to see than with the known arrangement in which the liquid can spread over the plate.
  • Liquid may be caused to flow along the channel by gravity for example by inclining the channel, or by other methods for example suction or propelling the liquid mechanically.
  • the channel may provide a depth of liquid above the deposition surface which could not be achieved by simply running a sample of liquid over a plane surface.
  • a channel reduces diversion due to build up of deposited material and allows the deposited material to act as a filter for particles still in suspension.
  • the sides of the channels slope outwardly from bottom to top.
  • the surface over which the sample flows and onto which the particles are initially deposited under the influence of the magnetic field is relatively wide, but the particles thus deposited on the sides of the channel can then slide down the slope to the bottom.
  • the trace is concentrated in the bottom of the channel making it more easily visible.
  • the channel has a flat bottom on which particles are to be deposited.
  • a flat bottom makes photography of the trace easier.
  • Ferromagnetic particles in the sample liquid are attracted towards the bottom of the channel by the magnetic field and deposited. Ferromagnetic particles tend to draw other non ferromagnetic particles, such as rubber, with them.
  • the apparatus is adjusted so that substantially all the particles are deposited within the length of the channel. If the downstream end of the channel is left substantially free of deposit, this ensures that the majority of particles have been deposited.
  • the strength of the magnetic field and the flow rate of the sample will affect the length of the trace.
  • the flow rate of the sample may be varied, for example, by altering the rate of supply of liquid to the channel, the viscosity of the liquid (e.g. by dilution or) or the slope of the channel.
  • the channel preferably has a smooth finish on at least its sides to enable the sample liquid to flow freely and the contaminating particles to slip down the sides of the channel to the bottom where they are to be deposited.
  • the deposition pattern depends on the type of particles in the liquid.
  • the trace tends to be tapered with the greatest density deposited where the liquid is supplied to the plate. Large particles produce a dark short trace, smaller particles give a longer trace of more constant density.
  • Plates produced according to the present invention with deposits can be stored for comparison with other plates.
  • Standard plates may be produced using samples with contaminating particles of known type and or size. These can be photographed or stored for comparison.
  • the magnetic field is most conveniently supplied by a magnet beneath the channel.
  • An electromagnet or permanent magnet may be used.
  • a horseshoe magnet is used with pole pieces spaced about 0.5mm apart, the air gap being situated immediately below the channel.
  • the channel is made in a material which is preferably opaque and preferably of a colour that contrasts with the colour of the contaminating particles likely to be deposited on it. White is suitable for most purposes.
  • a preferred form of a channel is a groove in a plate.
  • the plate is preferably of plastics material and preferably white in colour for the reason give above.
  • the plate may be injection moulded. Recesses may be provided in the surface of the plate opposite the groove. The recesses give the plate a more uniform thickness throughout which is of benefit if the plate is formed by injection moulding. If soft iron extensions are used on a permanent magnet it is preferable to magnetise the magnet after the pole pieces have been fitted. If the pieces are fitted after magnetisation the field strength is reduced as part of the magnetic field is lost immediately as its keep plate used during magnetisation is removed.
  • the thickness of the plate at the bottom of the channel is preferably as small as possible whilst preserving the structural strength of the plate so that the liquid in the channel can be placed as close as possible to the air gap between pole pieces of the magnet beneath the plate.
  • Fig. 1 shows a side view of an apparatus for assessing the nature and degree of contamination of liquids
  • Fig. 2 shows a front view of the apparatus of Fig. 1;
  • Fig. 3 shows a top plan view, on an enlarged scale, of a plate of the apparatus of Fig. 1;
  • Fig. 4 shows an underneath plan view of the plate of Fig. 3;
  • Fig. 5 shows an end elevation of the plate of Fig. 3;
  • Fig. 6 shows a section of the plate on the line VI-VI of Fig.
  • Fig. 7 shows a section of the plate on the line VII-VII of Fig. 3.
  • Fig. 8 shows a section of the plate and magnet on the line VIII-VIII of Fig. 3 on an enlarged scale.
  • die-cast metal stand 1 comprises a column portion 2 with a horizontal platform 3 extending to one side of its base.
  • a recess is formed in the upper surface of the platform for locating a beaker 4.
  • An inclined platform 5 is formed on the upper end of the column for supplying a plate 6.
  • a block 7 is supported, with its upper end in contact with the plate 6, by a bracket 8 secured to the stand by screws 9. The lower end of the block 7 is suspended over the beaker 4.
  • a horseshoe magnet 10 is mounted in the support stand 1.
  • the two poles of the magnet have soft iron pole piece extensions 11 mounted on them before the magnet is magnetised.
  • the plate is held in position on the inclined platform 5 by two spring clips 14 which are mounted on the support stand adjacent the upper end of the plate support platform 5.
  • a funnel 15 is positioned above the plate 6.
  • the funnel 15 has an integral mounting bracket 16 by means of which it is mounted in a recess in the side of the stand 1 between the two spring clips 14, and held in place by a screw 17.
  • the plate 6 (Figs. 3 to 8) is 50mm x50mmx3mm and is formed with a groove which is about 36mm long along the bottom of the groove.
  • the plate is 0.8mm thick at the bottom of the groove at its closed end 24 and decreases to 0.2mm thick towards the open end i.e. from 26 -27.
  • the bottom of the groove is 1.5mm wide and the sides slope up from the bottom at an angle of 30° to the vertical.
  • the plate is placed on the support platform 5 (Figs. 1 and 2) so that the magnetic gap 12 lies directly below the relatively thin bottom 22 of the groove with the poles either side of the centre line VI-VI.
  • One end of a needle 18 is set in a handle 19: the other end of the needle is inserted through the neck 20 of the funnel.
  • the needle is formed with a longitudinal groove so as to leave sufficient space for a viscous liquid to pass down, in the groove, between the needle and the inside of the neck of the funnel.
  • the free end of the needle 16 rests in a groove 21 in the plate 6. The handle and needle are free to be moved longitudinally up and down.
  • the plate 6 is approximately square in shape and is made from white plastics material by injection moulding.
  • the upper side of the plate 6 has a straight single groove 21 extending along a line of the plate from one edge of the plate to approximately 4/5 the way across the plate.
  • the groove has a flat bottom 22, sides 23 with curved junctions with the groove bottom.
  • the closed end 24 of the groove slopes down to an inclined portion 25 of the bottom which levels out relative to the surface of the plate at 26 towards the open end 27 of the groove.
  • On the underside of the plate are two recesses 28.
  • the recesses lie on either side of the centre line along which the groove runs.
  • Two notches 31 and 32 are formed in the edges of the plate along the centre line VI-VI.
  • the notch 31 nearest the upper closed end of the groove enables the plate to fit around the mounting bracket 16 for the funnel.
  • the notch 32 at the lower open ends of the groove receives the upper end block 7.
  • On the underside of the plate beneath the open end of the groove is a downward projection 30 which forms a spout for the sample liquid to flow along when leaving the groove.
  • the apparatus is used to test samples of lubricant as follows:
  • a sample of oil for example from a hydraulic system is mixed with solvent in a predetermined ratio.
  • a measured volume of the diluted sample is placed in the funnel 15 and allowed to run from the funnel down the needle groove into the upper end of the groove
  • the handle 19 is used to agitate the needle if the flow is hindered by a build-up of particles in the bottom of the funnel around the needle.
  • the liquid flows along the groove under gravity through the magnetic field of the magnet 10. Ferromagnetic particles are drawn down by the magnetic field onto the bottom and sloping side surfaces of the groove. Particles settling on the sloping sides slip down the sides to the bottom. Other contaminants such as rubber are drawn down with the ferromagnetic particles.
  • the deposited particles also act as a filter for particles still in suspension.
  • the liquid is allowed to drain off the plate into a waste beaker.
  • the plate is inclined to the horizontal to an angle that produces a pattern of deposited material of less than about

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  • Chemical & Material Sciences (AREA)
  • Biochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
  • Sampling And Sample Adjustment (AREA)

Abstract

On laisse s'écouler un liquide contaminé, tel qu'une huile lubrifiante, éventuellement diluée, verticalement le long d'un canal formé par une rainure à section trapézoïdale dans une plaque d'échantillons (6) en plastique blanc maintenue sur un support (2), la rainure présentant une pente vers le bas dans un champ magnétique créé entre des pièces polaires (11) sur un aimant permanent (10) en fer à cheval. L'échantillon de liquide est versé sur l'extrémité supérieure de la rainure par une entonnoir (15). Tout liquide restant dans la rainure est éliminé en douceur par lavage à l'aide d'un solvant et le dépôt restant dans la rainure est comparé visuellement avec des plaques d'échantillon standard préparées au préalable avec des liquides dont la contamination est connue.A contaminated liquid, such as a lubricating oil, possibly diluted, is allowed to flow vertically along a channel formed by a trapezoidal section groove in a sample plate (6) of white plastic held on a support ( 2), the groove having a downward slope in a magnetic field created between pole pieces (11) on a permanent magnet (10) in horseshoe. The liquid sample is poured over the upper end of the groove through a funnel (15). Any liquid remaining in the groove is gently removed by washing with a solvent and the deposit remaining in the groove is visually compared with standard sample plates prepared beforehand with liquids of known contamination.

Description

ASSESSING CONTAMINATION OF LIQUIDS
The present invention relates to a method and apparatus for assessing the nature and degree of contamination of liquids. It is especially useful for examining lubricating oils with a proportion of metallic contamination.
A known method of assessing contamination in lubricating oils uses a plane glass plate. A sample of oil is run down the plate while being subjected to a magnetic force from an electromagnet beneath the plate. The magnetic force pulls down ferromagnetic contaminating particles which are deposited on the plate.
The deposited particles are then viewed under red or green light to check the constitution of the contamination. The deposits are photographed for comparison with other photographs of specimen deposits from oil for which the constitution of the contaminating particles is known. The plates are quite large giving a trace about 20 cm long. The liquid spreads out as it runs down yielding a thin widely-spread deposit. A strong magnetic field is needed for it to affect the sample through the glass plate.
The present invention provides a method of assessing contamination in a sample of liquid comprising supplying a liquid sample to a channel and causing the sample to flow along the channel in a magnetic field so that contaminating particles are deposited in the channel.
The method provides a convenient way of assessing the nature and degree of contamination of liquids. Where necessary the liquids may first be mixed with a solvent to decrease its viscosity. The method produces a deposit of contaminating particles in the bottom of the channel, this deposit can be inspected under normal lighting and may be compared with other examples of deposition patterns.
The present invention provides in a second aspect apparatus for assessing contamination in a sample of liquid comprising a channel along which a sample of liquid can flow and means for providing a magnetic field in the path of the sample so that contaminating material is deposited in the channel. The apparatus may also include a means for supplying a sample of viscous liquid to the channel. The channel protects the deposited material so that residual liquid in the channel may be washed away with solvent. A channel with deposit can also be stored for later comparison with samples.
A preferred form of channel is formed by a plate having a straight groove extending to or towards at least one edge of the plate, the walls of the groove having a smooth finish, the plate being of effectively homogeneous material such as plastics material.
The channel provides a perdetermined path for a sample to flow along. The channel helps to confine the sample to the path. By thus restricting the spread of liquid the deposit is concentrated in the channel and the trace of deposit is easier to see than with the known arrangement in which the liquid can spread over the plate. Liquid may be caused to flow along the channel by gravity for example by inclining the channel, or by other methods for example suction or propelling the liquid mechanically.
The channel may provide a depth of liquid above the deposition surface which could not be achieved by simply running a sample of liquid over a plane surface. A channel reduces diversion due to build up of deposited material and allows the deposited material to act as a filter for particles still in suspension.
Preferably the sides of the channels slope outwardly from bottom to top. With this arrangement, the surface over which the sample flows and onto which the particles are initially deposited under the influence of the magnetic field is relatively wide, but the particles thus deposited on the sides of the channel can then slide down the slope to the bottom. Thus the trace is concentrated in the bottom of the channel making it more easily visible.
Preferably the channel has a flat bottom on which particles are to be deposited. Such a flat bottom makes photography of the trace easier.
Ferromagnetic particles in the sample liquid are attracted towards the bottom of the channel by the magnetic field and deposited. Ferromagnetic particles tend to draw other non ferromagnetic particles, such as rubber, with them.
Preferably the apparatus is adjusted so that substantially all the particles are deposited within the length of the channel. If the downstream end of the channel is left substantially free of deposit, this ensures that the majority of particles have been deposited. The strength of the magnetic field and the flow rate of the sample will affect the length of the trace. The flow rate of the sample may be varied, for example, by altering the rate of supply of liquid to the channel, the viscosity of the liquid (e.g. by dilution or) or the slope of the channel. The channel preferably has a smooth finish on at least its sides to enable the sample liquid to flow freely and the contaminating particles to slip down the sides of the channel to the bottom where they are to be deposited.
The deposition pattern depends on the type of particles in the liquid. The trace tends to be tapered with the greatest density deposited where the liquid is supplied to the plate. Large particles produce a dark short trace, smaller particles give a longer trace of more constant density.
Plates produced according to the present invention with deposits can be stored for comparison with other plates. Standard plates may be produced using samples with contaminating particles of known type and or size. These can be photographed or stored for comparison.
The magnetic field is most conveniently supplied by a magnet beneath the channel. An electromagnet or permanent magnet may be used. In the preferred embodiment a horseshoe magnet is used with pole pieces spaced about 0.5mm apart, the air gap being situated immediately below the channel.
The channel is made in a material which is preferably opaque and preferably of a colour that contrasts with the colour of the contaminating particles likely to be deposited on it. White is suitable for most purposes.
A preferred form of a channel is a groove in a plate. The plate is preferably of plastics material and preferably white in colour for the reason give above.
The plate may be injection moulded. Recesses may be provided in the surface of the plate opposite the groove. The recesses give the plate a more uniform thickness throughout which is of benefit if the plate is formed by injection moulding. If soft iron extensions are used on a permanent magnet it is preferable to magnetise the magnet after the pole pieces have been fitted. If the pieces are fitted after magnetisation the field strength is reduced as part of the magnetic field is lost immediately as its keep plate used during magnetisation is removed.
The thickness of the plate at the bottom of the channel is preferably as small as possible whilst preserving the structural strength of the plate so that the liquid in the channel can be placed as close as possible to the air gap between pole pieces of the magnet beneath the plate.
The present invention is further described by example with reference to the accompanying drawings, of which:-
Fig. 1 shows a side view of an apparatus for assessing the nature and degree of contamination of liquids;
Fig. 2 shows a front view of the apparatus of Fig. 1;
Fig. 3 shows a top plan view, on an enlarged scale, of a plate of the apparatus of Fig. 1;
Fig. 4 shows an underneath plan view of the plate of Fig. 3;
Fig. 5 shows an end elevation of the plate of Fig. 3;
Fig. 6 shows a section of the plate on the line VI-VI of Fig.
3;
Fig. 7 shows a section of the plate on the line VII-VII of Fig. 3; and
Fig. 8 shows a section of the plate and magnet on the line VIII-VIII of Fig. 3 on an enlarged scale.
As shown in Figs. 1 and 2, die-cast metal stand 1 comprises a column portion 2 with a horizontal platform 3 extending to one side of its base. A recess is formed in the upper surface of the platform for locating a beaker 4. An inclined platform 5 is formed on the upper end of the column for supplying a plate 6.
A block 7 is supported, with its upper end in contact with the plate 6, by a bracket 8 secured to the stand by screws 9. The lower end of the block 7 is suspended over the beaker 4.
A horseshoe magnet 10 is mounted in the support stand 1. The two poles of the magnet have soft iron pole piece extensions 11 mounted on them before the magnet is magnetised. There is an air gap 12 of 0.5mm between the pole piece extensions. The plate is held in position on the inclined platform 5 by two spring clips 14 which are mounted on the support stand adjacent the upper end of the plate support platform 5.
A funnel 15 is positioned above the plate 6. The funnel 15 has an integral mounting bracket 16 by means of which it is mounted in a recess in the side of the stand 1 between the two spring clips 14, and held in place by a screw 17.
The plate 6 (Figs. 3 to 8) is 50mm x50mmx3mm and is formed with a groove which is about 36mm long along the bottom of the groove. The plate is 0.8mm thick at the bottom of the groove at its closed end 24 and decreases to 0.2mm thick towards the open end i.e. from 26 -27. The bottom of the groove is 1.5mm wide and the sides slope up from the bottom at an angle of 30° to the vertical.
The plate is placed on the support platform 5 (Figs. 1 and 2) so that the magnetic gap 12 lies directly below the relatively thin bottom 22 of the groove with the poles either side of the centre line VI-VI.
One end of a needle 18 is set in a handle 19: the other end of the needle is inserted through the neck 20 of the funnel. The needle is formed with a longitudinal groove so as to leave sufficient space for a viscous liquid to pass down, in the groove, between the needle and the inside of the neck of the funnel. The free end of the needle 16 rests in a groove 21 in the plate 6. The handle and needle are free to be moved longitudinally up and down.
Referring again to Figs. 3 to 8, the plate 6 is approximately square in shape and is made from white plastics material by injection moulding.
The upper side of the plate 6 has a straight single groove 21 extending along a line of the plate from one edge of the plate to approximately 4/5 the way across the plate. The groove has a flat bottom 22, sides 23 with curved junctions with the groove bottom. The closed end 24 of the groove slopes down to an inclined portion 25 of the bottom which levels out relative to the surface of the plate at 26 towards the open end 27 of the groove. On the underside of the plate are two recesses 28. The recesses lie on either side of the centre line along which the groove runs. Two notches 31 and 32 are formed in the edges of the plate along the centre line VI-VI. The notch 31 nearest the upper closed end of the groove enables the plate to fit around the mounting bracket 16 for the funnel. The notch 32 at the lower open ends of the groove receives the upper end block 7. On the underside of the plate beneath the open end of the groove is a downward projection 30 which forms a spout for the sample liquid to flow along when leaving the groove.
The apparatus is used to test samples of lubricant as follows:
A sample of oil for example from a hydraulic system, is mixed with solvent in a predetermined ratio. A measured volume of the diluted sample is placed in the funnel 15 and allowed to run from the funnel down the needle groove into the upper end of the groove
21 on the plate 6. The handle 19 is used to agitate the needle if the flow is hindered by a build-up of particles in the bottom of the funnel around the needle. The liquid flows along the groove under gravity through the magnetic field of the magnet 10. Ferromagnetic particles are drawn down by the magnetic field onto the bottom and sloping side surfaces of the groove. Particles settling on the sloping sides slip down the sides to the bottom. Other contaminants such as rubber are drawn down with the ferromagnetic particles. The deposited particles also act as a filter for particles still in suspension. The liquid is allowed to drain off the plate into a waste beaker. The plate is inclined to the horizontal to an angle that produces a pattern of deposited material of less than about
20mm long. An angle of from 5 to 10° may be suitable.
After the entire sample has been run along the plate, excess oil is removed by gentle flushing with more solvent. The plate is then examined to assess the shape and density of the trace and is compared with plates produced from oil samples of known degree and type of contamination. These standard plates are produced by filtering samples to give contaminating particles of known size.

Claims

1. A method of assessing contamination in a sample of liquid comprising supplying a liquid sample to a groove in a plate and causing the sample to flow along the channel in a magnetic field so that contaminating particles are deposited in the groove.
2. A method according to claim 1 in which the groove is inclined to the horizontal and the sample caused to flow along the groove by gravity.
3. A method according to claim 1 or 2 in which liquid remaining in the groove is gently flushed away with solvent.
4. A method according to claim 1, in which the deposit formed in the groove is visually compared with one or more plates carrying deposits produced from liquids of known contamination.
5. Apparatus for assessing contamination in a sample of liquid comprising a plate having a groove along which a sample of liquid can flow, means for providing a magnetic field and support means for supporting the plate with the path of the sample in the magnetic field so that contaminating material is deposited in the groove.
6. Apparatus according to claim 5 in which the sides of the groove slope outwards from bottom to top.
7. Apparatus according to claim 6 in which the groove has a flat bottom.
8. Apparatus according to claim 5 in which the support means inclined to the horizontal and including means for supplying a sample of liquid to the upper end of the groove.
9. A plate for assessing contamination in a sample of viscous liquid having a groove forming a channel extending to or towards at least one edge of the plate, the walls of the groove having a smooth finish, the plate being of homogeneous material.
10. A plate according to claim 9 in which the material is opaque and of a colour, such as white, to contrast with contaminating particles.
11. A plate according to claim 9 in which the sides of the groove slope outwards from bottom to top and the width of the bottom of the groove is less than the depth of the groove.
EP19860906891 1985-11-22 1986-11-24 Assessing contamination of liquids Withdrawn EP0247120A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB08528767A GB2185570A (en) 1985-11-22 1985-11-22 Assessing contamination of liquids
GB8528767 1985-11-22

Publications (1)

Publication Number Publication Date
EP0247120A1 true EP0247120A1 (en) 1987-12-02

Family

ID=10588605

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860906891 Withdrawn EP0247120A1 (en) 1985-11-22 1986-11-24 Assessing contamination of liquids

Country Status (4)

Country Link
EP (1) EP0247120A1 (en)
AU (1) AU6721187A (en)
GB (1) GB2185570A (en)
WO (1) WO1987003368A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5540089A (en) * 1994-03-17 1996-07-30 Diagnetics, Inc. Ferrous particle collection apparatus
US5708198A (en) * 1994-03-17 1998-01-13 Diagnetics, Inc. Ferrous particle counter

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1168316A (en) * 1967-06-09 1969-10-22 Zeiss Jena Veb Carl Object Carrier, particularly for Interference Microscopes
US3554631A (en) * 1968-01-22 1971-01-12 Zeiss Jena Veb Carl Grooved object slide for interference microscope
DE2241143C3 (en) * 1971-08-25 1987-04-16 The Foxboro Co., Foxboro, Mass. Method and device for examining particles suspended in a fluid
US3947121A (en) * 1973-07-30 1976-03-30 Corning Glass Works Method for aligning microstructures
US4047814A (en) * 1974-02-27 1977-09-13 Trans-Sonics, Incorporated Method and apparatus for segregating particulate matter
WO1985004715A1 (en) * 1984-04-09 1985-10-24 The University College Of Swansea Method and apparatus for assessing particle deposits

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8703368A1 *

Also Published As

Publication number Publication date
WO1987003368A1 (en) 1987-06-04
GB8528767D0 (en) 1985-12-24
GB2185570A (en) 1987-07-22
AU6721187A (en) 1987-07-01

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