CA1275975C - Method and apparatus for cleaning of screen-cloths in particular at vibrating screening equipment - Google Patents

Method and apparatus for cleaning of screen-cloths in particular at vibrating screening equipment

Info

Publication number
CA1275975C
CA1275975C CA000494641A CA494641A CA1275975C CA 1275975 C CA1275975 C CA 1275975C CA 000494641 A CA000494641 A CA 000494641A CA 494641 A CA494641 A CA 494641A CA 1275975 C CA1275975 C CA 1275975C
Authority
CA
Canada
Prior art keywords
screen cloth
tensioning
tension
screen
profiles
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
CA000494641A
Other languages
French (fr)
Inventor
Karl H. Eggerstedt
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.)
MOGENSEN (FREDRIK) AB
Original Assignee
MOGENSEN (FREDRIK) 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 MOGENSEN (FREDRIK) AB filed Critical MOGENSEN (FREDRIK) AB
Application granted granted Critical
Publication of CA1275975C publication Critical patent/CA1275975C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B07SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07BSEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B1/00Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
    • B07B1/46Constructional details of screens in general; Cleaning or heating of screens
    • B07B1/48Stretching devices for screens
    • B07B1/485Devices for alternately stretching and sagging screening surfaces
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B07SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07BSEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B1/00Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
    • B07B1/46Constructional details of screens in general; Cleaning or heating of screens
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B07SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07BSEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B1/00Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
    • B07B1/46Constructional details of screens in general; Cleaning or heating of screens
    • B07B1/50Cleaning
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B07SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07BSEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B2201/00Details applicable to machines for screening using sieves or gratings
    • B07B2201/04Multiple deck screening devices comprising one or more superimposed screens

Landscapes

  • Combined Means For Separation Of Solids (AREA)
  • Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)

Abstract

ABSTRACT OF THE DISCLOSURE

A method and apparatus is disclosed of cleaning screen cloths such as those used in a vibratory multi-deck screening equipment. The cloth is tensioned in the direction of flow of material.
During the operation, the tension of the cloth is relieved to allow the fluttering thereof with the result that the cloth is at least partially cleaned.
Then, the cloth is tensioned again.

Description

~2~7~9~i METHOD AND APPARATUS FOR CLEANING OF SCREEN-CLOTHS
IN PARTICULAR AT VIBRATING SCREENING EQUIPMENT
_ The invention concerns a method and an apparatus fo~
cleaning of screen cloths especially for vibrating multi deck screening equipment where a screen cloth is held between tensioning profiles and tensioned in the direction of the flow of material on the screen cloth by means of at least one tensioning device connected to ak -~ least one of the tensioning profiles.
When a sticky material is fed through vibrating screening equipment there is frequently a tendency for the matexial to stick to the screen cloth and such an adherence is ofken difficult to remove. Further difficulties can appear when a material contains particles which are nearly the same size as the mesh aperture of the screen cloth and thereby can wedge into the mesh.
-~ These two kinds of problems with screen cloth often result in a more or less rapid reduction of the screening capacity in that th3 screening surface is reduced by the adherence of the material.
`~ It has already been suggested that the removal of par~icles adhering to the apertuxes of the mesh could be made by means o~ applying bouncing or hammering devices to the screen cloth whereby the wedging particles are knocked out of the mesh. With binding caused by sticky or particulate and sticky materials these bouncing or hammering devices have hardly been effective. In this ~- case it has so far often been necessary to stop the screening equipment from time to time and thoroughly clean the screen cloth. Such an effort is hardly commercially defensible because of the downtime of the " equipment and loss of produ~tion.

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Other equipment is known where a screen cloth can be slackened in a direction which is at right angle to the flow of material on the screen cloth (U5 - P 3655045).
The disadvantage of that system is, however, that the waves of the fluttering are oriented in ~he direction of the flow of material thereby forcing it to accumulata in the troughs or nodes and thus creating individual flows instead of the even distribution of material across the screen cloth which is desired and important for the ;~ 10 screening process.
As the load of material on a screen cloth always is heaviest on its first part and binding of both kinds most fre~uently appear in this region it is important to concentrate the f luttering there. With a transversely tensioned system this is impossible; on the contrary, one can expect that the heavier load of material on the first part of screen cloth will limit its fluttering movement more than the relatively less loaded second part.
The present invention aims at avoiding the disadvantages of the known equipment and solving the problem so that a sufficient cleaning of the screen cloth is possible also during the continuous operation of the ;- screening machine, i.e. without any real loss of production.
It is therefore suggested that, according to the invention, during the continuous vibration of the screening equipment the screen cloth is slackened ~- longitudinally until the particles sticking to the screen cloth or being wedged into the mesh are removed by the fluttering of the screen cloth and after that the screen cloth is tensioned again. This process of slackening and tensioning of the screen cloth could also be repeated.
It can further be organized so that appropriate intervals ~; are automatically arranged by means of a timing device.
Thereby the degree of slackening of the screen cloth "~
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should be possible to define, ad~ust and repeat and, depending upon type of screen cloth as well as frequency and amplitude of vibration, preferably ad~ustable between 2 and ~ mm.
The slackening of the screen cloth gives a fluttering movement which brings an intensive shaking out and removal of binding or adhered particles so that the screen cloth is kept optimally clean and thereby maintaining maximum possible capacity.
An apparatus to perform the method according to the invention could have tensioning devices which engage the tensioning profiles of the screen cloth and which are equipped with pneumatical cylinders connected to a compressed air supply in a fashion that is in principle already known. The tensioning profiles of the screen cloth could also be connected to the frame of the equipment by means of tensioning springs and the ~- slackening of the screen cloth could then be made bymeans of electromagnetic devices. It could be suitable to link the tensioning device to the tensioning profiles of the screen cloth through guides by means of flexible oints e.g. hinges, leaf springs etc.
It has proven advantageous to arrange covering or deflecting plates for the material above the tensioning ~; 25 profiles and devices.
In order to increase the cleaning effect there could ~` be supporting or hammering profiles at the screen cloth.
According to a broad aspect the invention relates to :~ a method for cleaning screen cloths, particularly screen cloths mounted in a multi-deck screening apparatus having vibratory mechanisms, comprising the steps of: mounting a screen cloth so as to be held between at least firs~
and second tensioning proiles, tensioning said screen cloth between said tensioning profiles in a direction of flow of material on said screen cloth with a tensioning ';;
''' ~

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'~ ' ' ' ' ' . ' . ': ' ' . - ,' ~;275~5 device coupled to at least one of said tensioning profiles, operating said screening equipment so as to vibrate said screen cloth and during said step of operating said screening equipment, decreasing a longitudinal tension of the screen cloth to flutter the screen cloth until at least some of the particles which have adhered to wires forming the screen cloth are removed and retentioning said screen cloth.
According to another broad aspect the invention relates to an apparatus for cleaning screen cloths, particularly screen cloths mounted in a multi-deck screening apparatus having vibratory mechanisms, wherein each said screen cloth is mounted and held between at least first and second tensioning profiles and tensioned in the direction of flow of material on said screen cloth; comprising: a tensioning device coupled to at least one of said tensioning profiles to control the tension of the screen cloth, means for reducing the tension applied by said ~ensioning device so as to slacken said screen cloth as said screen cloth is vibrated by a respective vibrating mechanism whereby s particles which have adhered to wires forming the said screen cloth are at least partially removed and means for retentioning said screen cloth following such partial removal.
With reference to the enclosed drawings the invention will be further explained. The drawings show:
Figure 1 is a schematic view of a multi-deck screening apparatus with three screen cloths;
Figure 2 is an arrangement of a screen cloth with tensioning device in a screening equipment frame, in side view;
- Figure 3 is a partial view from above showing this screen cloth with tensioning device; and Figure 4 is another example of a tensioning device ::

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with the screen cloth in a frame of a screening equipment.
In the drawings, the screen cloths are indicated by 10 which at one end are fitted to stationary tensioning profiles 11. The other end of the screen cloths 10 are connected to moveable tensioning profiles 12. In the example as shown in figure 1 to 3 the tensioning profiles 12 are connected through guides 21 to tensioning devices 14 which are fitted to the frame of the screening equipment 13 and which are equipped with a pneumatic cylinder for e.g. air or oil. When the pneumatic ` pressure is increased the piston of the cylinder moves to the xight in the direction of the arrow and tensions the screen cloths. When the pressure is reduced the lS piston moves in the direction of the arrow to the let and the screen cloth 10 is slackened. The tensioning system could also be organized in a reverse fashion so ~; that an increased pressure slackens the screen cloth and a reduced pressure tensions it. The pneumatic medium is brought to the cylinder 14 through khe conductor 18.
Fig. i shows the arrangement of three screen cloths 10 ~; with tensioning devices 14 in a screening apparatus 20, ;~ equipped with vibrating devices 19.
The arrangement according to figure 4 shows how the screen cloth is tensioned by means of the tensioning profile 12 being mounted of the frame of the screening equipment 13 by means of tensioning springs 15. In this case the slackening of the screen cloth 10 is achieved by the tensioning profile 12 being pulled to the let in the direction of the arrow by m ans or electromagnets 16.
When the eIactromagnets are switched off the springs 15 retension the screen cloth.
There are of course also other suitable tensioning devices which fit the scope of this invention.
. , .
.

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, .. . .
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Claims (11)

1. A method for cleaning screen cloths, particularly screen cloths mounted in a multi-deck screening apparatus having vibratory mechanisms, comprising the steps of:
mounting a screen cloth so as to be held between at least first and second tensioning profiles;
tensioning said screen cloth between said tensioning profiles in a direction of flow of material on said screen cloth with a tensioning device coupled to at least one of said tensioning profiles;
operating said screening equipment so as to vibrate said screen cloth; and during said step of operating said screening equipment, decreasing a longitudinal tension of the screen cloth to flutter the screen cloth until at least some of the particles which have adhered to wires forming the screen cloth are removed; and retentioning said screen cloth.
2. A method according to claim 1, wherein said steps of decreasing a longitudinal tension and retentioning the screen cloth are repeated.
3. A method according to claim 1, wherein said steps of decreasing a longitudinal tension and retentioning the screen cloth are automatically controlled by means of a timing device.
4. A method according to claim 1, wherein the amount of decrease in tension of the screen cloth is predetermined and can be repeated and adjusted.
5. A method according to claim 4, wherein the degree of slackening of the screen cloth is adjustable between approx-imately 2 and 8 mm depending upon the type of screen cloth as well as the frequency and the amplitude of vibration.
6. An apparatus for cleaning screen cloths, particularly screen cloths mounted in a multi-deck screening apparatus having vibratory mechanisms, wherein each said screen cloth is mounted and held between at least first and second tensioning profiles and tensioned in the direction of flow of material on said screen cloth; each end of said screen cloth being connected to a tensioning profile; comprising:
a tensioning device coupled to at least one of said tensioning profiles to control the tension of the screen cloth;
means for reducing the tension applied by said tensioning device so as to slacken said screen cloth as said screen cloth is vibrated by a respective vibrating mechanism whereby par-ticles which have adhered to wires forming the said screen cloth are at least partially removed; and means for retentioning said screen cloth following such partial removal.
7. An apparatus as in claim 6, wherein said tensioning device comprises tensioning means coupling one of said tension-ing profiles of said screen cloth to a machine frame of said apparatus and wherein said means for reducing tension and retentioning said screen cloth include at least one pneumatic cylinder mounted between said tensioning profile and said machine frame and operable to vary a tension applied to said screen cloth.
8. An apparatus as in claim 6, wherein said tensioning device comprises tensioning means coupling one of said tension-ing profiles of said screen cloth to a machine frame of said apparatus and wherein said means for reducing tension and retention said screen cloth include at least one electromagnetic device mounted between said tensioning profile and said machine frame and operable to vary a tension applied to said screen cloth.
9. An apparatus according to claim 6, wherein an elastic coupling is provided between the tensioning profile of the screen cloth and the tensioning device.
10. An apparatus according to claim 6, wherein at least one cover or deflecting plate is provided above the tensioning profile and the tensioning device.
11. An apparatus according to claim 6, wherein the screen cloth is resting against at least one supporting or hammering profile.
CA000494641A 1984-11-06 1985-11-05 Method and apparatus for cleaning of screen-cloths in particular at vibrating screening equipment Expired - Fee Related CA1275975C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19843440403 DE3440403A1 (en) 1984-11-06 1984-11-06 METHOD AND DEVICE FOR CLEANING THE SCREEN BOTTOMS. FOR VIBRATION CLASSIFIERS
DEP3440403.1 1984-11-06

Publications (1)

Publication Number Publication Date
CA1275975C true CA1275975C (en) 1990-11-06

Family

ID=6249545

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000494641A Expired - Fee Related CA1275975C (en) 1984-11-06 1985-11-05 Method and apparatus for cleaning of screen-cloths in particular at vibrating screening equipment

Country Status (9)

Country Link
EP (1) EP0184006A1 (en)
JP (1) JPS61181578A (en)
AU (1) AU4941685A (en)
CA (1) CA1275975C (en)
DE (1) DE3440403A1 (en)
DK (1) DK510285A (en)
FI (1) FI854345A (en)
NO (1) NO854386L (en)
ZA (1) ZA858531B (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3771722D1 (en) * 1987-11-13 1991-08-29 Inst Cerna Metalurgija VIBRATION SCREEN.
DE4344199C1 (en) * 1993-12-23 1995-02-23 Ivt Industrietechnik Gmbh Stretching device for screens
FI20011927A (en) * 2001-10-02 2003-04-03 Pertti Tommila vibrating screens
CN107999370B (en) * 2017-12-22 2024-02-09 农业部南京农业机械化研究所 Self-cleaning anti-blocking peanut grading device
CN112774971B (en) * 2020-12-29 2022-04-26 颍上县健辉农牧有机肥有限公司 Organic fertilizer screening equipment capable of automatically cleaning animal hair and broken stones
CN115626496B (en) * 2022-12-19 2023-04-11 常州速稳智能机械有限公司 Piezoelectric drive-based screening and conveying device and working method thereof
CN116955961B (en) * 2023-08-25 2024-02-09 江苏秦郡机械科技有限公司 Intelligent roller cage screen cleaning effect evaluation method and system
CN118122614B (en) * 2024-05-06 2024-07-23 山东铭城环保新材料科技有限公司 Red mud classification screening system for preparing high-strength slope protection stone

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2279042A (en) * 1940-08-03 1942-04-07 Inland Lime & Stone Company Screening apparatus
GB1086474A (en) * 1965-05-27 1967-10-11 G Pk I Gipromashugleobogaschen Device for mounting of wire screens on screening machines
DE1263467B (en) * 1967-01-10 1968-03-14 Gutehoffnungshuette Sterkrade Device for fixing sieve panels in sieve frames
US3655045A (en) * 1969-10-30 1972-04-11 Ajax Flexible Coupling Co Inc Method and apparatus for conveying and separating materials
DE2131976B2 (en) * 1971-06-26 1975-03-27 Maschinenfabrik Jaeger & Co Kg, 3253 Hessisch Oldendorf Continuously-operating sifting machine - with alternately taut and slackened base and single vibratory system with stepped sieve base
DE2226968A1 (en) * 1972-06-02 1973-12-13 Albert Wehner ELASTIC CONVEYOR, SCREEN OR FILTER BASE WITH VIBRATION DRIVE
DE2924506A1 (en) * 1979-06-18 1981-01-29 Mogensen Gmbh & Co Kg Multi-layered sieve for fine granular material - has two sieve bases of equal mesh size avoiding overloading when sieving mostly fine material
AU545288B2 (en) * 1980-10-13 1985-07-11 Dabmar Manufacturing Co. Pty. Ltd. Vibrating screen

Also Published As

Publication number Publication date
DK510285D0 (en) 1985-11-05
EP0184006A1 (en) 1986-06-11
JPS61181578A (en) 1986-08-14
ZA858531B (en) 1986-07-30
FI854345A0 (en) 1985-11-05
DK510285A (en) 1986-05-07
AU4941685A (en) 1986-05-29
DE3440403C2 (en) 1990-04-05
NO854386L (en) 1986-05-07
FI854345A (en) 1986-05-07
DE3440403A1 (en) 1986-05-07

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