CA2178796C - Method for filtering out particles from a fluid - Google Patents

Method for filtering out particles from a fluid Download PDF

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Publication number
CA2178796C
CA2178796C CA002178796A CA2178796A CA2178796C CA 2178796 C CA2178796 C CA 2178796C CA 002178796 A CA002178796 A CA 002178796A CA 2178796 A CA2178796 A CA 2178796A CA 2178796 C CA2178796 C CA 2178796C
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CA
Canada
Prior art keywords
filter
filter element
fluid
particles
housing
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 - Fee Related
Application number
CA002178796A
Other languages
French (fr)
Other versions
CA2178796A1 (en
Inventor
Eric Gustaf Lundin
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.)
Nyfotek AS
Original Assignee
Nyfotek AS
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 Nyfotek AS filed Critical Nyfotek AS
Publication of CA2178796A1 publication Critical patent/CA2178796A1/en
Application granted granted Critical
Publication of CA2178796C publication Critical patent/CA2178796C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D33/00Filters with filtering elements which move during the filtering operation
    • B01D33/06Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums
    • B01D33/073Filters with filtering elements which move during the filtering operation with rotary cylindrical filtering surfaces, e.g. hollow drums arranged for inward flow filtration
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D33/00Filters with filtering elements which move during the filtering operation
    • B01D33/35Filters with filtering elements which move during the filtering operation with multiple filtering elements characterised by their mutual disposition
    • B01D33/37Filters with filtering elements which move during the filtering operation with multiple filtering elements characterised by their mutual disposition in parallel connection
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D33/00Filters with filtering elements which move during the filtering operation
    • B01D33/44Regenerating the filter material in the filter
    • B01D33/52Regenerating the filter material in the filter by forces created by movement of the filter element
    • B01D33/56Regenerating the filter material in the filter by forces created by movement of the filter element involving centrifugal force
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D33/00Filters with filtering elements which move during the filtering operation
    • B01D33/70Filters with filtering elements which move during the filtering operation having feed or discharge devices
    • B01D33/72Filters with filtering elements which move during the filtering operation having feed or discharge devices for feeding
    • B01D33/727Filters with filtering elements which move during the filtering operation having feed or discharge devices for feeding provoking a tangential stream
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2201/00Details relating to filtering apparatus
    • B01D2201/28Position of the filtering element
    • B01D2201/287Filtering elements with a vertical or inclined rotation or symmetry axis

Abstract

A method for filtering out particles from a fluid is disclosed, wherein unfiltered fluid is guided into a filter housing of a filter apparatus and filtered fluid is guided from the filter housing, and wherein a rotary filter element, which has a filter structure and is arranged in the filter housing and is rotatable about an axis thereof, is rotated at a speed which is sufficiently high that all particles passing in a fluid flow into the area of the rotary filter element are affected by its structure and are ejected therefrom, whereas the fluid passes the structure of the rotary filter element substantially freed from the particles and flows off from the filter housing.

Description

METHOD FOR FILTERING OUT PARTICLES
FROM A FLUID
The invention relates to a method for filtering out particles from a fluid, wherein unfiltered fluid is guided into a filter housing of a filter apparatus and filtered fluid is guided from the filter housing. A filter element is positioned in rotary manner in the filter housing and may be provided with a substantially cylindrical configuration and with a structure, through which the fluid flows from the outside to the inside.
In general, methods for filtering out particles from a fluid and filter to apparatus are known, in which a fluid containing contaminants in the form of particles is forced or sucked through the pores of a filter medium. The particles are left behind on the filter medium, whereas the fluid passes through said filter medium. Such a filter medium provided with pores has a certain flow resistance, which increases over a period of time with an increasing degree of contamination of the filter medium. After a certain time the flow resistance becomes so high that the filter medium must be cleaned. This gives rise to considerable manual effort and costs.
The object of the invention is to provide a method for filtering out particles from a fluid which is operable without the need for cleaning a filter 2 o medium from contamination, which avoids the increase of the flow resistance resulting from contamination of the filter medium, and which is therefore more economical.
According to the invention this object is achieved by a method for filtering out particles from a fluid, wherein unfiltered fluid is guided into a filter 2 s housing of a filter apparatus and filtered fluid is guided from the filter housing, and wherein a rotary filter element, which has a filter structure and is arranged in the filter housing and is rotatable about an axis thereof, is rotated at a speed which is sufficiently high that all particles passing in a fluid flow into the area of the rotary filter element are affected by its structure and are ejected therefrom, whereas the fluid passes the structure of the rotary filter element substantially freed from the particles and flows off from the filter housing.
From a flow standpoint, the filter is designed in such a way that within the filter the fluid flows along a circular path on the filter element, the fluid being able to pass through the filter element, and whereas particles contained in the fluid are ejected away by the filter element rotating at a correspondingly high speed.
A particularly good filtering action is obtained if the fluid flow direction coincides with the rotation direction of the filter element.
An advantage of the filter according to the invention is that the particles to be filtered out cannot jam in the pores of the filter element or be deposited on the filter element, and consequently the latter is not contaminated.
Therefore, there is no need to replace the filter element or clean the same.
Instead the particles to be filtered out sink downwards into the filter housing and are deposited there. On its underside the filter housing has a discharge lock through which the deposited particles can be removed.
The filter for practising the method of the present invention is a filter for filtering out particles being carried in a fluid. The filter has a substantially-cylindrical filter housing into which the fluid enters, and a filter element rotatably arranged within the housing. Fluid flow is from the outside to the inside of the filter element. The filter element is rotatable at a sufficiently high speed that all of the particles in the fluid come into contact with a structure of the filter element and are ejected outwardly away from that structure. Fluid flow into the filter housing is guided so as to be substantially tangential to the structure of the filter element, and the direction of the fluid flow corresponds to the rotation direction of the filter element.
The filter element may be cylindrical, and may have a cylindrical cage. The structure of the filter element may be formed by bars running substantially parallel to its longitudinal axis, and may be grid-like. The structure may have a filter cloth or a porous ceramic material layer. The filter element may comprise a substantially-tubular flexible filter cloth which at the operating speed is subject to the centrifugal force of its substantially-cylindrical filtration arrangement.
The filter housing may have a substantially-circular cross-section, and may have a fluid inlet so positioned that the fluid flows substantially in a tangential direction into the filter housing. The filter housing may have a substantially-circular-cylindrical configuration, and on its top the filter housing may have an outlet for the fluid which is positioned substantially centrally in the filter housing. The filter housing may have a discharge lock on its underside. The filter element may have an upper part and a disk-shaped lower part, between which is located a filter medium; this filter element has a substantially-circular-cylindrical outer contour, and the upper part has a discharge opening.
The invention is a process for filtering out particles from a fluid using a filter that comprises a substantially-cylindrical filter housing into which the fluid enters, and a filter element rotatably arranged within the housing. Fluid flow is from the outside to the inside of the filter element. The process comprises a first step of feeding the fluid into the filter housing at a tangential angle to the filter element and in the same direction as the rotation direction of the filter element.
A second step involves rotating the filter element at a sufficiently high speed that all of the particles in the fluid come into contact with a structure of the filter element and are ejected outwardly away from that structure.
The invention is next described in greater detail by means of preferred embodiments utilizing the accompanying drawings, in which:
Figure 1 is a cross-sectional side view of a filter illustrating the method of the invention;
Figure 2 is a cross-sectional plan view of the filter of Figure 1;
Figure 3 is a schematic representation of the interaction between a rotating filter element and particles in a fluid;
Figure 4a is a partially-sectioned side view of another filter illustrating the method of the invention;
Figure 4b is a cross-sectional plan view of the filter of Figure 4a, the view being along the line 4b-4b in Figure 4a;
Figure 4c is a cross-sectional side view of a strut of the filter of Figure 4a, the view being along the line 4c-4c in Figure 4a; and, Figure 5 is a schematic perspective view of another filter in accordance with the invention, the view illustrating a series of filter elements arranged to act in parallel within a single housing.
According to Figures 1 and 2, the filter has a filter housing 10, in which is rotatably mounted a filter element 6. The filter housing 10 has a substantially-cylindrical shape, which is funnel-shaped at its lower end. In a lower area of the filter housing is located an inlet 12 for a fluid to be filtered.
The filter housing 10 and inlet 12 are so designed that the fluid entering through the inlet flows substantially at right angles to the longitudinal axis and tangentially to the wall of the cylindrical filter housing 10 into the filter. An outlet 13 for the filtered fluid is located on the top of the filter housing 10.
The filter element 6 also has substantially-cylindrical outer contours.
The filter element 6 is so mounted in the filter housing 10 that a spacing is maintained between the wall of the filter housing 10 and the outer contour of the filter element 6. In this area the fluid flowing through the inlet 12 tangentially to the wall of the filter housing 10 flows around the filter element 6 until the fluid passes through the filter element and then flows out of the filter via the outlet 13.
Thus, a flow forms around the filter element 6. The flow rotation direction coincides with the rotation direction of the rotary filter element 6.
The operation of the filter according to the invention will now be described having regard to Figure 3. The fluid circulating in the area around the rotary filter element 6 has on its circular path a much lower circumferential speed than the filter element. This naturally also applies to the particles entrained in the fluid on which acts a centrifugal force, directed away from the filter element, due to the circular movement.
However, when the fluid passes through the filter element in order to leave the filter through the outlet 13 in a cleansed form, the particles that are to be filtered are entrained in the direction of the filter element despite the centrifugal force. Those particles then strike against the filter element rotating at a sufficiently high speed, rebound therefrom, and consequently remain on a circular path in the area between the filter element 6 and the housing 10.
This process can be repeated many times, until finally the circulating particles sink downwards under the force of gravity, and are deposited in the lower part of the filter housing. Since the particles striking against the filter element are ejected therefrom due to the high speed of the filter element before they penetrate the pores of the filter element and since, due to the centrifugal force acting thereon, the particles do not have an adequate energy to remain in the pores of a filter medium, no contamination of the filter element occurs.
Optimum flow conditions in the area between the filter element 6 and the filter housing 10 occur if there is a minimum of turbulence. Particularly on the wall of the filter housing there is a laminar surface flow layer. The particles preferably sink downwards in that layer. The particles enter that layer on the one hand because the centrifugal force acts thereon, and on the other hand on rebounding from the filter element.
A particularly uniform flow distribution is assisted in that the inlet 12 is located at the bottom, and the outlet 13 at the top, of the filter housing 10. This leads to an upwardly-directed circular flow in the spacing area, with a very uniform distribution of the particle-charged fluid over the entire filter element surface.
Virtually all standard filter materials can be used as the filter medium, provided that they have a structure running in a cylindrical longitudinal direction. It is also possible to use smooth filter cloths, as will be described in greater detail hereinafter.
Filter element 6, suitable for the filter according to the invention, can essentially have the following structure. Between a disk-shaped upper part and a disk-shaped lower part is fitted a tubular filter element. In the centre of the upper part there is an opening through which can pass out the filtered fluid.
The upper part and/or lower part are mounted in rotary manner in the filter housing.
According to Figure 1, a filter element comprises a perforated sheet.
The meshes of the perforated sheet are arranged in the longitudinal and transverse directions to the rotation axis of the filter element. The webs of the perforated sheet running in the cylindrical longitudinal direction are essential for the filtering action.
In another construction, the filter element merely comprises longitudinally-directed bars, which are uniformly circumferentially distributed. The spacing between the bars is e.g. 1 mm, and the bar thickness is e.g. 4 mm. The filter element has a diameter of e.g. 6 to 8 cm, and a height of e.g. 20 cm.
The bars or perforated sheet can be covered with a filter cloth, which could then be referred to as a "filter medium".
In a third filter element construction, a filter cloth is fitted between the upper part and the lower part. It is particularly appropriate for the filter cloth to be constituted by a fabric, which has thicker threads running in the cylindrical longitudinal direction, and thinner threads in the circumferential direction.
Compared with a perforated sheet or bars in a filter element covered with a filter cloth, the same filtering action is obtained with a lower filter element rotation speed. This advantageous effect is due to the denser arrangement of the vertical structural elements essential for the filtering action. Nevertheless, the filter cloth must naturally have sufficiently large passages for the fluid to be filtered.
Due to the lower rotary speed, the loading of the bearings and the intensity of the vibrations if an imbalance occurs are lower.
In another construction the filter element has a hollow ceramic body which, from its outside to its inside, has pores extending towards the outlet.
This construction is particularly suitable for filtering liquids.
Figure 4a is a partially-sectioned side view of another embodiment of a filter according to the invention. The filter housing 10 has a design essentially in the form of a cylinder of revolution. At its upper end the filter housing 10 is closed by a cover 1, which is fixed by clips 2 to the filter housing. In the centre of the cover is located a ball bearing 3, in which is mounted the upper part 5 of the filter element 6. The bearing shaft of the upper part 5 is hollow and extends through the cover 1 through a corresponding opening therein. The hollow bearing shaft of the upper part 5 forms the outlet 13 through which the filtered fluid can leave the filter.
A rotary seal 4 seals the cover 1 in the vicinity of the ball bearing 3 against the bearing shaft of the filter element 6.
The lower end of the filter housing 10 tapers in a funnel-shaped manner and ends in a connecting piece with a discharge lock 11. By opening the discharge lock the dirt which has collected in the lower part of the filter housing can be removed. Above the funnel-shaped taper of the filter housing 10 is located a bearing block 9, which carries a ball bearing 8 located in the centre of the filter housing 10. The bearing block 9 has four radially-directed struts (cf. the sectional representation of Figure 4b), which extend radially to the wall of the filter housing 10, and by means thereof the bearing block 9 is connected to the filter housing 10.
In the lower area of the filter housing 10, but above the struts of the bearing block 9, there is an inlet 12 for the fluid that is to be filtered.
A filter medium, e.g. a filter cloth, is positioned between the upper part 5 and the lower part 7. To the underside of the lower part 7 is fitted a plurality of radially-directed laminations, whose lower end is approximately level with the inlet 12. The upper part 5, the filter medium and the lower part 7 form a rotor, which can be driven from the outside by means of the bearing shaft. By means of the laminations located on the lower part 7 and which act in the manner of a blower or fan, the fluid flowing in through the inlet 12 is given a circular flow in the spacing area between the rotating filter medium and the wall of the filter housing 10.
Figure 4b is a cross-sectional plan view of the filter, by means of which it is possible to see the central position of the filter element 6 within the filter housing 10. It is also possible to see the struts 16 of the bearing block 9, and the arrangement of the inlet 12.
Figure 4c is a cross-sectional side view of a strut of the bearing block 9. The struts 16 have an elongated, elliptical cross-section. The particles sinking in the spacing area between the filter element 6 and the wall of the filter housing 10 consequently drop between the struts 16, through into the funnel-shaped taper of the filter housing 10 without being deposited on the struts 16.
Figure 5 is a schematic perspective view of a third embodiment of a filter according to the invention, in which three filter elements 6 are juxtaposed to within a common filter housing 10. A distributing pipe 15 is positioned laterally at the bottom of the filter housing 10; it distributes the fluid to be filtered over three inlets associated with the three filter elements 6. On the top of the filter housing there is a common outlet 13'. In addition, at the top of the filter housing 10 is provided a drive machine 14, which by means of a drive belt or other suitable drive means can rotate the three filter elements 6. The filter housing is subdivided into two chambers, one chamber containing the rotating filter element 6. The outlets of the three filter elements issue into the second chamber with the common outlet 13'.

Claims (13)

1. A method for filtering out particles from a fluid, wherein unfiltered fluid is guided into a filter housing of a filter apparatus and filtered fluid is guided from the filter housing, and wherein a rotary filter element, which has a filter structure and is arranged in the filter housing and is rotatable about an axis thereof, is rotated at a speed which is sufficiently high that all particles passing in a fluid flow into the area of the rotary filter element are affected by its structure and are ejected therefrom, whereas the fluid passes the structure of the rotary filter element substantially freed from the particles and flows off from the filter housing.
2. A method according to claim 1, wherein the fluid flow is directed from a radial spacing between the filter housing and the filter element through the structure of the filter element to the inside of the filter element.
3. A method according to claim 1 or 2, wherein the particles are ejected outwards from the rotating filter element.
4. A method according to claim 1, 2 or 3, wherein the fluid flow is guided substantially tangentially to the filter element.
5. A method according to any one of claims 1 to 4, wherein the rotary filter element is substantially cylindrical and the fluid flow in a radial spacing between the filter housing and the substantially cylindrical filter element is directed in a circumferential direction which corresponds to the rotary direction of the filter element.
6. A method according to any one of claims 1 to 5, wherein the particles which rebound from the rotating filter element move to a particle outlet.
7. A method according to claim 6, wherein the particles are discharged continuously through the particle outlet.
8. A method according to any one of claims 1 to 7, wherein the fluid flow is guided through the structure of the filter element which is formed by bars extending substantially parallel to the rotational axis.
9. A method according to claim 8, wherein the fluid flow is guided through the bars which are disposed in an essentially uniform circumferential arrangement with a spacing between the bars of about 1 mm and a bar thickness of about 4 mm.
10. A method according to claim 8 or 9, wherein the bars are covered by a filter cloth.
11. A method according to any one of claims 1 to 7, wherein the structure of the filter element is formed by a grid or perforated sheet.
12. A method according to any one of claims 1 to 7, wherein the structure of the filter element is formed of porous ceramics.
13. A method according to any one of claims 1 to 12, wherein the fluid is a gaseous fluid.
CA002178796A 1995-06-16 1996-06-11 Method for filtering out particles from a fluid Expired - Fee Related CA2178796C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19521963A DE19521963C1 (en) 1995-06-16 1995-06-16 Filtering of particles in a fluid
DE19521963.5 1995-06-16

Publications (2)

Publication Number Publication Date
CA2178796A1 CA2178796A1 (en) 1996-12-17
CA2178796C true CA2178796C (en) 2000-11-14

Family

ID=7764546

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002178796A Expired - Fee Related CA2178796C (en) 1995-06-16 1996-06-11 Method for filtering out particles from a fluid

Country Status (6)

Country Link
EP (1) EP0748645B1 (en)
JP (1) JPH09826A (en)
AT (1) ATE195437T1 (en)
CA (1) CA2178796C (en)
DE (2) DE19521963C1 (en)
ES (1) ES2151979T3 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19844441A1 (en) * 1998-09-28 2000-04-06 Lundin Filter Gmbh Device and method for separating particles from a fluid
JP4542749B2 (en) * 2003-04-23 2010-09-15 前澤工業株式会社 Filtration device
ITAN20100014A1 (en) * 2010-02-11 2011-08-12 Crea Srl SELF-CLEANING SELF-CLEANING FILTER CONTINUOUS.
NL2011332C2 (en) * 2013-08-23 2015-02-24 Flamco Bv Dirt and/or gas removal device.
DE102015015285A1 (en) * 2015-10-02 2017-04-06 Mr. Wash Autoservice AG Apparatus and method for cleaning service water

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1207441A (en) * 1958-04-15 1960-02-16 Rotary filter
US3152078A (en) * 1963-03-14 1964-10-06 Pennsalt Chemicals Corp Stationary-walled centrifuge
US3392114A (en) * 1965-05-26 1968-07-09 Ingersoll Rand Canada Apparatus and method for decontaminating pulp and paper machine effluent
US3443696A (en) * 1967-05-01 1969-05-13 Little Inc A Solid-fluid separating device
CH602161A5 (en) * 1975-12-11 1978-07-31 Escher Wyss Ag
WO1990007968A1 (en) * 1989-01-10 1990-07-26 The Coca-Cola Company Frontal separator system for separating particles from fluids

Also Published As

Publication number Publication date
ATE195437T1 (en) 2000-09-15
DE59605748D1 (en) 2000-09-21
EP0748645A3 (en) 1997-04-02
CA2178796A1 (en) 1996-12-17
DE19521963C1 (en) 1996-10-24
EP0748645A2 (en) 1996-12-18
JPH09826A (en) 1997-01-07
EP0748645B1 (en) 2000-08-16
ES2151979T3 (en) 2001-01-16

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