EP0883716A1 - Dispositif d'ecumage de la couche superficielle d'un liquide - Google Patents

Dispositif d'ecumage de la couche superficielle d'un liquide

Info

Publication number
EP0883716A1
EP0883716A1 EP97906363A EP97906363A EP0883716A1 EP 0883716 A1 EP0883716 A1 EP 0883716A1 EP 97906363 A EP97906363 A EP 97906363A EP 97906363 A EP97906363 A EP 97906363A EP 0883716 A1 EP0883716 A1 EP 0883716A1
Authority
EP
European Patent Office
Prior art keywords
liquid
separating
inlet
surface layer
inlet member
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Withdrawn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
EP97906363A
Other languages
German (de)
English (en)
Inventor
Bengt-Olof Gustafsson
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.)
Alfa Laval AB
Original Assignee
Alfa Laval AB
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 Alfa Laval AB filed Critical Alfa Laval AB
Publication of EP0883716A1 publication Critical patent/EP0883716A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B15/00—Cleaning or keeping clear the surface of open water; Apparatus therefor
    • E02B15/04—Devices for cleaning or keeping clear the surface of open water from oil or like floating materials by separating or removing these materials
    • E02B15/10—Devices for removing the material from the surface
    • E02B15/106—Overflow skimmers with suction heads; suction heads
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
    • B01D17/02—Separation of non-miscible liquids
    • B01D17/0208—Separation of non-miscible liquids by sedimentation
    • B01D17/0214—Separation of non-miscible liquids by sedimentation with removal of one of the phases

Definitions

  • the present invention refers to a device for skimming a surface layer of a liquid, comprising a separating member, which is arranged to be submerged in the liquid, at an operating position and has a first inlet member, positioned at a first inlet level below the free liquid surface of the surface layer and enabling a primary inflow of said surface layer to a space of the separating member, and which separating member has an outlet member arranged to enable an outflow of liquid from said space at a level positioned below the first inlet member.
  • the invention refers to a separating equipment for separating a first relatively light component from a liquid containing at least the first relatively light component and a second relatively heavy component, said equipment comprising a separating member, which is arranged to be submerged in the liquid to an operating position and has a first inlet member, positioned at a first inlet level below a free liquid surface of a surface layer of the liquid, said layer having a high concentration of the relatively light component, and enabling a primary inflow of said surface layer to a space of the separating member, and which separating member has an outlet member arranged to transport a flow of liquid from said space at a level positioned below the first inlet member to a centrifugal separator arranged to separate the first component of this flow from the second component.
  • a tubular separator In order to be able to provide such a separation, t is known to use a tubular separator. This is kept submerged in the liquid by means of floating members in such a manner that an upper edge of the separator is positioned immediately below the surface layer of the liquid. Moreover, such a separator comprises a pump member which transports the liquid flowing into the separator over said edge from the lower part of the separator.
  • separators in practice do not function satisfactorily since they may not be kept in a stable position at the liquid surface. Frequently, this means that the separator will be emptied and thus air will be sucked out through the outlet causing great problems in a subsequent centrifugal separator for the final separation.
  • the problem is due to the fact that if the outflow from the separator is not as large as the inflow thereto the liquid level m the separator will be changed. If, for instance, the outflow from the separator is larger than the inflow the liquid level n the inner space of the separator decreases. This means that the weight of the separator decreases and thus it is lifted to a somewhat higher position n the liquid, leading to a smaller inflow over the edge, and m this way the separator will displace itself from a position of equilibrium with an accelerated velocity.
  • EP-A-679 767 discloses such a device for separating a surface layer of a liquid.
  • This device comprises an inlet member at the level of the surface layer and the liquid flowing into the inner space of the device through the inlet member is sucked away by means of a suction device.
  • the device comprises floating memoers having a lifting force which is controllable by permitting the liquid to flow into the floating members.
  • the inflow of liquid into the floating members is controlled by regulating the pressure m these members by means of pressurized air.
  • SU-A-1 714 040 discloses a surface separator for separating oil being present on the sea surface. Thereby, the separator is submerged in the sea and by means of floating members kept on such a level that an inlet provided m an upper end of the separator will be positioned at essentially the sea surface.
  • the inlet comprises a valve member arranged to open when the separator is at the top of a wave and close when the separator is at the bottom of a wave.
  • JP-A-6 142 647 discloses a sludge separator having a container connected to a pump for the transport of a sludge from the container.
  • the container comprises a floating piston device having an inlet passage being provided centrally and vertically and through which sludge is sucked to the inner space of the container and from there further to an outlet.
  • EP-A-389 275 discloses a surface separator for separating a surface layer of a liquid.
  • the separator is partly submerged in the liquid and comprises a chamber through which the liquid may flow and a slightly sloping separating plate provided in the chamber m such a manner that it slopes upwardly in the flow direction of the liquid. Thereby, the surface layer of the liquid will flow upwardly on the separating plate and out through an outlet passage while the rest of the liquid flowing through the chamber flows beside the separating plate below the same.
  • the object of the present invention is to remedy the problem mentioned above and provide a device enabling an equal and stable separation of a surface layer.
  • it is an aim that the outlet of the device in every situation is provided with liquid, .e. preventing the mixing of air in the liquid separated.
  • the device initially defined and characterized by a second inlet member which, when the separating member is in said operating position, is provided below the first inlet member and arranged to enable a secondary inflow of liquid to said space.
  • a second inlet member which, when the separating member is in said operating position, is provided below the first inlet member and arranged to enable a secondary inflow of liquid to said space.
  • the second inlet member ensures that the primary flow plus the secondary flow are essentially equal to the outflow. Thereby, the mixing of air in the outflow is also effectively prevented.
  • the outlet member is arranged to be connected to members for transporting liquid from said space.
  • the separating member comprises a floating member arranged to keep the separating member in said operating position.
  • means are arranged to enable the displacement of the first inlet member in relation to the free liquid surface of the surface layer for the regulation of the primary inflow.
  • Such a possibility of regulation enables control of the mixing relation between the liquid, which via the primary inflow arrives from the surface layer, being enriched of the relatively light component, and the liquid which via the secondary inflow arrives from a layer below this surface layer, m the outflow which, for instance, is supplied to a centrifugal separator connected to the outlet member.
  • the concentration of the components of the liquid separated may be adapted to the centrifugal separator in such a manner that the latter may operate under optimal conditions .
  • the second inlet member has an opening area which is adjustable for the regulation of the secondary inflow.
  • This enables adjustment of the reaction velocity of the device, i.e. the velocity by which the separating member compensate for e.g. a variation in the outflow.
  • the opening area of the second inlet member may advantageously be automatically adjustable n such a manner that if the liquid level in said space sinks below a predetermined level the opening area increases and if the liquid level rises above this predetermined level the opening area decreases .
  • the separating member comprises a container device having an end which opens upwardly and forms the first inlet member.
  • the second inlet member may comprise a passage through a wall of the container device.
  • the opening area of the second inlet member may be adjustable by means of a valve body provided in the passage of the wall. This may be connected to a floating member, which is provided in the container device and arranged to displace the valve body and thus adjust the opening area when the liquid level in the container device is changed with respect to the predetermined level.
  • the first inlet member comprises an edge of the container device, which is adjustable with respect to the free liquid surface m such a manner that said edge is positioned immediately below the free liquid surface of the surface layer when the separating member is in said operating position.
  • the separating device initially defined and characterized in that the separating device comprises a second inlet member which, when the separating member is in said operating position, is provided below the first inlet member and arranged to enable a secondary inflow of liquid to said space.
  • Fig 1 discloses a side-view of a separating arrangement having a separating device according to the present invention.
  • Fig 2 discloses a partly sectional side-view of a separating device according to a first embodiment of the invention.
  • Fig 3 discloses a partly sectional side-view of a separating device according to a second embodiment of the invention.
  • Fig 4 discloses a partly sectional side-view of a separating device according to the third embodiment of the invention.
  • Fig 5-8 disclose four different variants of an inlet member of the separating device according to the invention.
  • a vessel 1 or larger container which opens upwardly.
  • the vessel 1 contains a liquid 2, which in this example is for instance a cutting liquid for a machine tool 3 schematically disclosed as an example.
  • the machine tool 3 sucks cutting liquid via an outlet conduit from the vessel 1 and recirculates contaminated liquid to the vessel 1 via an outlet conduit.
  • the cutting liquid used and recirculated is contaminated and contains different impurities, at least a part of which is a relatively light impurity, such as a oil product. Since the specific weight of such a light impurity is lower than the specific weight of the cutting liquid 2, these impurities will float up to the surface of the liquid 2 and form a surface layer 4.
  • a separating member 5 is submerged in the vessel 1 for separating the surface layer .
  • the separating member 5 comprises a first inlet member 6, which is positioned at the surface layer 4, a second inlet member 7 and an outlet member 8. Furthermore, the separating member 5 comprises floating bodies 9 keeping the separating member 5 at an appropriate level in the liquid 2, 4.
  • the floating bodies 9 are fixedly provided on an annular holder 10 which has an inner thread which is in engagement with an outer thread 11 of the separating member 5 which in the example disclosed is shaped as a circular cylinder.
  • the separating member 5 is, via the outlet member 8 and an outlet conduit 12 connected to a centrifugal separator 13.
  • the surface layer 4 and the liquid 2 which flow into the separating member 5 via the first and second inlet members 6 and 7, are thus supplied to the centrifugal separator 13 in which a final separation of the cutting liquid and the impurities is performed.
  • These impurities are discharged through an outlet conduit 14 and the cutting liquid purified is recirculated via a conduit 15.
  • the separating member 5 is shaped as a container which opens upwardly.
  • the first inlet member 6 is formed by the upper edge of the container 5, which is inclined in the example disclosed in Fig 2.
  • the second inlet member 7 is formed by a passage in the wall of the container 5.
  • the outlet member 8 is formed by a passage extending through the wall of the container 5 and being located in the proximity of the bottom 16 of the container 5.
  • the container 5 encloses a space 17 receiving liquid 2, 4 flowing inwardly through the first inlet member 6 and the second inlet member 7.
  • the floating bodies 9 are adjusted in such a manner that the first inlet member 6 m a basic adjustment will be located immediately below the free liquid surface of the surface layer 4. Furthermore, the floating bodies 9 are adjusted and provide such a lifting force that this basic adjustment is obtained essentially independent of the amount of liquid in the space 17.
  • the centrifugal separator 13 or a pump provided in the outlet conduit 12 is arranged in such a manner that it will transport the liquid from the space 17 m a relatively constant flow.
  • the basic adjustment frequently is such that a primary inflow of the surface layer 4 and a part of the liquid to therebeneath flows m through the inlet member 6, which primary flow is somewhat less than the outlet flow flowing out through the outlet member 8.
  • the liquid level 18 of the liquid present in the space 17 would s nk.
  • a secondary inflow through the second inlet member 7 will prevent the liquid level 18 from sinking.
  • the size of the secondary inflow is determined by the height difference between the free liquid surface of the surface layer 4 and the liquid level 18.
  • the pressure difference from the liquid columns of the liquid on both sides of the wall of the container 5 will result in the secondary inflow.
  • This also means that if the liquid level in the space 17 sinks this level difference will be greater and the pressure by which the secondary inflow is influenced increases leading to a greater secondary inflow and thus resulting in the rise of the liquid level 18.
  • the secondary inflow will decrease if the liquid level 18 rises since the level difference and thus the pressure by which the secondary inflow is influenced will decrease.
  • the outlet member 8 comprises an outlet conduit 19 extending downwardly into the space 17 and having an orifice m a lower part of the space 17.
  • the outlet conduit 19 is connected to the centrifugal separator 13 m tne same way as the outlet conduit 12.
  • this second embodiment comprises an annular member 20 which has an inner thread and which is in engagement with an outer thread 21 of the cylindrical separating member 5.
  • the outer thread 21 is located in the area of the second inlet member 7 and has such a length that the member 20 may be turned in relation to the separating member 5 in such a way that the member 20 covers a variable part of the opening area of the second inlet member 7. In this way the sensitivity of the separating member 5 and by which the secondary inflow compensate for the deviation of the liquid level 18 from a position of equilibrium may be adjusted in advance.
  • Fig 4 discloses a third embodiment of the invention.
  • the second inlet member 7 is provided as a passage in the bottom 16 of the separating member 5.
  • this embodiment has a valve device for automatically regulating the opening area of the secondary inlet member 7 in such a way that if the liquid level 18 sinks under a predetermined level the opening area increases and if the liquid level rises above this predetermined level the opening area decreases.
  • the valve device comprises a conical valve body 22 and a floating element 23.
  • the valve body 22 is mechanically connected to the floating element 23 by means of a bar 24.
  • the floating element 23 will lift the upwardly tapered conical valve body 22 upwardly in such a manner that the opening area of the annular passage of the second inlet member 7 will decrease. If the liquid level 18 in the space 17 sinks below said predetermined level, the valve body 22 will due to its weight be pulled downwardly and thus the opening area of the passage of the second inlet member 7 increases.
  • the secondary inflow may thus be increased m an accelerating manner when the liquid level 18 sinks and be decreased in a corresponding way when the liquid level 18 rises.
  • the reaction velocity by which the separating member 5 compensates for a deviation from a position of equilibrium will increase.
  • the first inlet member 6 may, as is disclosed in Fig 5-8, be shaped in many different ways.
  • the first inlet member 6 is formed by the separating member 5 being obliqually cut. Thereby, the width of the first inlet member 6 increases when the separating member 5 sinks in relation to the free liquid surface of the surface layer 4.
  • the first inlet member 6 may also m a simple embodiment be formed by an edge perpendicularly cut, as is disclosed in Fig 6. By such an edge a maximal length of the first inlet member 6 is obtained which enables the greatest possible inflow of the surface layer 4.
  • such an inlet member is very sensitive, i.e. a small deviation from a position of equilibrium rapidly results in a great change of the primary inflow.
  • the first inlet member 6 comprises a plurality of slotted recesses 25 provided in the wall of the separating member 5.
  • Fig 8 discloses a recess 28 provided m the wall of the separating member 5 and tapering downwardly. Such a recess 26 will function in essentially the same manner as the inclined edge disclosed in Fig 1-5. It should be noted that the edge disclosed m Fig 5-8 and forming the inlet member may be displaceable in a vertical direction in relation to the separating member 5 as an alternative or complement to the adjustability of the floating bodies 9.
  • the thickness of the surface layer 4 merely is schematically disclosed.
  • the surface layer 4 may in certain applications be very thick and for instance extend downwardly below the first inlet member 6.
  • the surface layer 4 may be a thin film on the surface of the liquid 2 or accumulations of impurities floating on the surface.
  • the container of the separating member 5 may have another than a circular cylindrical shape, it may e.g. be square or rectangular in a cross-section.
  • the floating bodies 9 may be attached to the separating member 5 in many different ways. For instance, they may by means of a holder be fixedly provided onto the separating member 5 and each of the floating bodies may be displaced on its respective holder.
  • the valve device disclosed in Fig 4 may be shaped in many different ways. For instance, it may comprise an inner cylinder which is raised ana lowered m relation to a passage provided m a side wall of the separating member 5.
  • a filter may be provided around the separating member 5 and in particular outside the first inlet member 6 and the second inlet member 7 in order to prevent larger particles, fibres and for instance mould accumulations from being sucked into the separating member 5.
  • the separating device according to the invention is applicable for purifying many different types of liquids.
  • the mere requirement is that the liquid components to be purified should have specific weight which deviates from the specific weight of the component contaminated and that the relatively lighter component thus will float on the surface of the relatively heavier component.
  • Beside purifying cutting liquid the separating device according to the invention may thus be used to separate oil products and other greases from water and cleaning liquid within the industry. This is of special interest for the modern cleaning liquids which nowadays are used within the industry and in which oil impurities rises to the surface.
  • the separating device may be used when collecting oil from the sea, lakes and other pools of water.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Environmental & Geological Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Removal Of Floating Material (AREA)
  • Centrifugal Separators (AREA)

Abstract

Dispositif permettant de séparer la couche superficielle (4) d'un liquide (2) au moyen d'un élément de séparation (5) disposé de manière à rester imergé dans le liquide en position de fonctionnement. Cet élément séparateur (5) comprend une première admission (6) disposée en position de fonctionnement, en un premier niveau d'admission situé au dessous de la surface de liquide libre de la couche superficielle (4), ce qui autorise un premier afflux de ladite couche superficielle dans un espace (17) de l'élément séparateur, et un élément de sortie (8) disposé de manière à permettre un afflux de liquide depuis l'espace précité (17) à un niveau situé en deçà du premier élément d'admission. L'élément séparateur (5) comprend en outre un deuxième élément d'admission (7) qui, lorsque l'élément séparateur est en position de fonctionnement, se situe au dessous du premier élément d'admission (6) et permet un deuxième afflux de liquide dans l'espace précité (17).
EP97906363A 1996-03-01 1997-02-14 Dispositif d'ecumage de la couche superficielle d'un liquide Withdrawn EP0883716A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE9600823A SE506242C2 (sv) 1996-03-01 1996-03-01 Anordning för att avskilja ett ytskikt hos en vätska
SE9600823 1996-03-01
PCT/SE1997/000249 WO1997032087A1 (fr) 1996-03-01 1997-02-14 Dispositif d'ecumage de la couche superficielle d'un liquide

Publications (1)

Publication Number Publication Date
EP0883716A1 true EP0883716A1 (fr) 1998-12-16

Family

ID=20401645

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97906363A Withdrawn EP0883716A1 (fr) 1996-03-01 1997-02-14 Dispositif d'ecumage de la couche superficielle d'un liquide

Country Status (4)

Country Link
EP (1) EP0883716A1 (fr)
AU (1) AU2107797A (fr)
SE (1) SE506242C2 (fr)
WO (1) WO1997032087A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999057378A1 (fr) 1998-05-06 1999-11-11 Mantis Oil Separation Limited Recuperateur a deversoir et systeme de flottation

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2781688B1 (fr) * 1998-07-28 2000-09-29 Georges Ceresoli Separateur de liquides non miscibles
FR2788229A1 (fr) * 1999-01-12 2000-07-13 Yves Guibert Crepine flottante pour aspiration de liquides de surface
BR0000655C1 (pt) * 2000-02-22 2002-05-14 Edson De Sousa Dispositivo para limpar a superfìcie de interface lìquido e ar, a céu aberto
FR2816339B1 (fr) * 2000-11-09 2003-07-11 Sorelec Procede et installation de recuperation d'une nappe flottant a la surface d'un liquide

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5075014A (en) * 1990-05-04 1991-12-24 Imc-International Marketing Of Canada Corp. Oil recovery system and apparatus

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IN170493B (fr) * 1989-03-22 1992-04-04 Saleam Essop
US4956100A (en) * 1989-06-13 1990-09-11 Aqua-Aerobic Systems, Inc. Method and apparatus for mixing and surface skimming water treatment basins
CH680342A5 (fr) * 1989-11-21 1992-08-14 Wagner Umweltschutz Ag
DE9406918U1 (de) * 1994-04-26 1994-06-30 JPM Ingenieurtechnik GmbH, 24558 Henstedt-Ulzburg Vorrichtung zur Absaugung von Flüssigkeiten aus Gewässern

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5075014A (en) * 1990-05-04 1991-12-24 Imc-International Marketing Of Canada Corp. Oil recovery system and apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999057378A1 (fr) 1998-05-06 1999-11-11 Mantis Oil Separation Limited Recuperateur a deversoir et systeme de flottation

Also Published As

Publication number Publication date
AU2107797A (en) 1997-09-16
SE9600823D0 (sv) 1996-03-01
WO1997032087A1 (fr) 1997-09-04
SE9600823L (sv) 1997-09-02
SE506242C2 (sv) 1997-11-24

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