CA1202602A - Screening system - Google Patents
Screening systemInfo
- Publication number
- CA1202602A CA1202602A CA000416949A CA416949A CA1202602A CA 1202602 A CA1202602 A CA 1202602A CA 000416949 A CA000416949 A CA 000416949A CA 416949 A CA416949 A CA 416949A CA 1202602 A CA1202602 A CA 1202602A
- Authority
- CA
- Canada
- Prior art keywords
- screen
- elements
- screening
- stiffening
- frame
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07B—SEPARATING 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
- B07B1/00—Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
- B07B1/46—Constructional details of screens in general; Cleaning or heating of screens
- B07B1/4609—Constructional details of screens in general; Cleaning or heating of screens constructional details of screening surfaces or meshes
- B07B1/4645—Screening surfaces built up of modular elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07B—SEPARATING 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
- B07B1/00—Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
- B07B1/46—Constructional details of screens in general; Cleaning or heating of screens
- B07B1/48—Stretching devices for screens
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
- B07B—SEPARATING 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
- B07B1/00—Sieving, screening, sifting, or sorting solid materials using networks, gratings, grids, or the like
- B07B1/46—Constructional details of screens in general; Cleaning or heating of screens
- B07B1/48—Stretching devices for screens
- B07B1/49—Stretching devices for screens stretching more than one screen or screen section by the same or different stretching means
Abstract
CANADIAN PATENT APPLICATION
OF
BENGT LARS ARNE DEHLÉN
and SVEN-ERIK DYRUP
FOR
SCREENING SYSTEM
Abstract of the Disclosure:
A screen deck comprises several elongated screen elements and is retained against the supporting elements of a screen frame by means of stiffening elements includ-ed in the screen elements The stiffening elements may serve independently as the one part of a fastening arrange-ment by being elastically deformed against the support-ing elements with a spring-back force resultant which is at least as large as an oppositely directed inertia resultant acting on the screen elements during screening in a dynamic screening machine. On using stiffening elements of magnetic material, the screen elements are retained against the screening frame, or their retention may be increased, by means of permanent magnets magnetical-ly attracting the stiffening elements.
OF
BENGT LARS ARNE DEHLÉN
and SVEN-ERIK DYRUP
FOR
SCREENING SYSTEM
Abstract of the Disclosure:
A screen deck comprises several elongated screen elements and is retained against the supporting elements of a screen frame by means of stiffening elements includ-ed in the screen elements The stiffening elements may serve independently as the one part of a fastening arrange-ment by being elastically deformed against the support-ing elements with a spring-back force resultant which is at least as large as an oppositely directed inertia resultant acting on the screen elements during screening in a dynamic screening machine. On using stiffening elements of magnetic material, the screen elements are retained against the screening frame, or their retention may be increased, by means of permanent magnets magnetical-ly attracting the stiffening elements.
Description
~z~o~
The present invention relates to a screen compris-ing a screen frame with supporting elements for a screen deck inserted in the screen frame, and fastening means for the screen deck.
Many different fastening methods have been used in the mounting of screens for dynamic screening machines.
According to, for example, DE-OS 2,849,838 published September 13, 1979 - Hein L~hm~nn AG, a snap-on system has been used in which the separate screen elements have been snapped onto enlarged supporting elements. Similar modes of fastening are utilized in DE-GM 78 38 335 pub-lished April 5, 1979 - Gummi-Kueper GMBH and Co. KG and DE-OS 2,749,489 published June 1, 1978 - Binder and Co.
In some cases, fastening has been accomplished by pro jections on the underside of the screen cloths and ex-pansion means adapted to urge said projections into engagement with recesses provided in the supporting elements of the screen frame. Such constructions are shown in, for example, U.S. patent specification 4,141,821 issued February 27, 1979 - Steinhaus GMBH and also in U.S. patent specification 3,745,736 issued July 17, 1973 - A. Fisher et al.
However, the above-mentioned screening machines with small individually fastenable screen elements are not often used since they necessitate reconstruction of existing screening machines. The most commonly used variant of screening machines makes use instead of screen cloths oP substantial size, very often 1-2 m2 per unit.
This type of screen cloths are fastened in the screen frames by providing the screen cloth units with hooks by which the screen cloth units are clamped between opposed edges of the screen frame. An example of such a clamping method is disclosed in DE-OS 2,005,376, published August 19, 1971 - Gummi-Kueper GMBH and Co. KG.
This fastening method is utilized for the majority .~
B
~20;2~0Z
of all screening machines which at present are manufactured all over the world, as a result oE which the frame con-structions of most screening machines are of a similar kind. As will appear from some of the above-mentioned publications, it has been tried to divide the screen deck into smaller units which are readily exchangeable to facilitate rapid exchange o a worn section and also to afford an opportunity for rapidly shifting from one hole size to another within a section of the screen deck.
The disadvantage of known smaller screen elements is that the frame construction of the screening machines used on the market must be redesigned or completed be-fore the readily exchangeable screen element systems according to, for example, DE-OS 2,754,374 published June 13, 1979 - Gummi-Kueper GMBH a~d Co. KG can be utilized.
It is one object of the present invention to pro-vide a far-reaching simplification of prior art screen constructions with smaller screen elements and to allow of a simpler and cheaper mounting on location, without necessitating any essential alteration of the frame construction of the screening machine.
According to the present invention, it is re~uired in a screen comprising a screen frame with supporting ~ID~Z
elements for a screen deck mounted in the screen frame and fastening means for the screen deck, that the said screen deck comprises several elongated screen elements placed adjacent each other and havin~ stiffening ele-ments which are included in the screen elements and which, upon mounting in the screen frame, are prestress-ed against the supporting elements by elastic deforma-tion.
The invention thus is based on the idea that the separate screen elements forming said screen deck should be formed as elongated and rigid plank-like elements and, upon m~unting, be subjected to an elastic deforma-tion in order to provide the required holding-down force against the supporting elements of the screen frame.
Compared with the conventional systems where the separate screen cloths are provided at their edges with retention hooks by which the cloths are prestressed, the present invention makes it much easier to apply the requisite holding-down force against the supporting elements of the screen frame. Thus~ if the screen frame is designed in such a manner that the supporting ele-ments force the screen elements to curve convexly, the screening elements can be formed with straight stif-fening elements. One end of the screen elements is then secured to the frame, and the screen elements are bent over the supporting elements to be secured underneath a hold-down rib at the opposite side of the screen frame. The force required for bending the screen ele-ments will be considerably less than a force directedin the plane of the screen elements and applied in order to stretch the screen elements to such an extent that the same holding-down force is obtained.
The screening system according to the invention can be utilized not only for screening machines in which the screen decks are curved convexly, but also in screen-ing machines with planar decks~ In such a case, it is possible, according to a development o~ the invention, to plastically deform the stiffening elements in a di-rection opposite to the elastic deformation to which the stiffening elements are subjected during mounting of the screen elements in the screening machine. In the present invention, it is best if the stiffening elements~ when the screen elements are mounted in the screen frame, are subjected to an elastic deformation whose spring-back force resultant is at least as large as an inertia resultant acting on the screen elements in the opposite direction, when the screen elements are used in a dynamic screening machine. If it should be difficult ko obtain such a strong elastic deforma-tion, it is possible, according to the present inven-tion! to increase the holding-down force by utilizing permanent magnets which preferably are mounted in the supporting elements of the screen frame and which are caused to act against magnetic inserts in the screening cloth. These magnetic inserts may consist of the said sti~fening elements.
~IL2~;~6~
The present invention therefore provides a screening system comprising a screen frame with supporting elements for a screen deck inserted in the screen frame, and fast-ening means for the screen deck which comprises several screen elements placed adjacent each other and having screen stiffening means consisting of stiffening elements which are included in the screen elements and which are pre-stressed against the supporting elements by elastic deformation upon mounting in the screen frame, wherein the screen elements each have a length to width ratio of at least 3:1, and wherein the stiffening elements are mounted in the screen frame with an elastic deformation whose spring-back force resultant is at least as large as an inertial force resultant acting on the screen deck in a direction opposite to the spring-back force resultant when the screen deck is used in a dynamic screening machine.
In a preferred embodiment the screen elements have a length to width ratio of at least 4:1, preferably at least 5:1. By this arrangement, the stiffening elements will lie closer to one another, and thus the total holding-down force will be greater, without it being necessary, upon mounting of the individual elements, to exert an inconven-iently great force on the free ends of the elements when they are bent down and mounted in the screen frame.
In a still further embodiment the stiffening elements are mounted in the screen frame with an elastic deformation whose spring-back force resultant is at least as large as an inertial force resultant acting on the screen deck in a direction opposite to the spring-back force resultant when the screen deck is used in a dynamic screening machine.
~92602 I~ permanent magnets are utilized for providing or lmproving tne holding-down force, these magnets should be disposed on the supporting elements of the screen frame, preferably by being connected therewith via elas-tlc dampers.
The invention will be described in more detail in the following, reference being had to the accompa-nying drawings ln which Fig. 1 is a perspective view of an example of a screen element in accordance with the present invention;
Fig. 2 is a perspective view of parts of the screen frame of a screening machine to illustrate ~he mounting of the screen elements;
Fig. 3 is a perspective view of another embodiment o~ a screen element according to the present invention;
Fig. 4 is a longitudinal section oE a part of a screening machine with screen elements accorairlg to a further embodiment of the invention;
Fig~ 5 is a section along line V-V in Fig. 4; and Fig. 6 is a section along line VI-VI in Figl 4;
Fig. 7 is a transverse section through a further embodiment of the screening system where the screening deck is divided into two juxtaposed areas.
Fig. 1 shcws a screen element consisting of an elastomer~ for instance natural or synthetic rubber~
such as polyurethane. The screen element has holes 2 made during the manufacture of the element. Reinforcing or stiffening elements 3 are insertea along the longi-tudinal sides of the screen elementO These reinforcing elements are made of rigid material and may consist of metallic square tubes~ as illustrated in the draw-ings. If necessary, the screen elements may also bereinforced with a suitable number of laid-in stiffening elements 4 extending at right angles to the stiffening or reinforcing elements 3. The screen element is then formed for overlap jointing by being provided with a recess 5 at one long side and an overlap flange 6 at the other long side.
Fig. 2 shows an example of a screen frame in a screening machineO The screen frame has side members 7, hold-down ribs 8 and longitudinal supporting elements 9. The side members 7 also are provided with supporting surfaces 10. In the embodiment illustrated, the support-ing surfaces 10 and the supporting elements 9 are mount-ed at different levels, such that the screen elements 1 will curve upwardly over the supporting elements 9.
As will appear from Fig. 2, the screen elements are mounted by ~lamping their one ends against the sup-porting surface 10 by means of the hold-down rib 8, whereupon the elements are pressed down over the sup-porting elements 9 by being subjected to a force in the direction of the arrow 11. Finally, the elements 1 are retained in this elastically deformed position by securing the hold-down rib 8 to the left in Fig. 2.
The present invention thus utilizes the elasticity or spring ~orce provided by the stiffening elements 3 in order to obtain the requisite holding-down action against the supporting elements 9 during the subsequent use of the screening machine. The holding-down action ~20,~0~
can be very large if an appropriate material is select-ed for the stiffening elements 3. These elements may consist of, for example, metallic material which is rigid and can be subjected to heavy elastic deformation without surpassing the 0.2~ yield strength during mount-ing. However, the stiffening elements 3 may also be formed of other materials, such as glass fiber rods or other rigid bars placed in the screening cloth ele-ments either at the long side edges only, as is shown in Fig. 1, or at suitable intervals in the lateral di-rection of the screen elements (= the screening direc-tion of the screQning machine).
In the embodiment according to Figs. 1 and 2, the invention has been utilized in connection with a screen-ing machine with a convexly curved screen deck. As has been mentioned above, the invention may also ~e utilized with screening machines in which the finished screen deck i5 planar, in which case the stiffening elements may have been subjected to a plastic predeformation (see Fig. 3) such that the screen elements are curved in à direction opposite to the elastic deformation im-parted to them during mounting. In Fig. 3, this plastic predeformation is illustrated by the arrows 12 which indicate the amount by which the screen elements de-viate from a straight line 13.
If it is desired, according to a further development of invention, to strengthen the holding-down force or to avoid deformation of the screen elements during mount-ing, it is possible in accordance with Figs. 4-6, to pro-~0~
vide a holding-down force by means of permanent magnets 13 which, by means of resilient holders 14 serving as dampers, are mounted on the longitudinal supporting elements 9 of the screen frame. In the embodiment illu-strated, the holders 14 are fi~edly mounted on the lon-gitudinal supporting elements 9 by means of a holder plate 15 secured by means of bolts 16 (Fig. 5) or by welding (Fig. 6).
The permanent magnets 13 attract the stiffening elements 3 which are inserted in the screen elements and which, in this instance, must consist of magnetic material to be able to function as armatures. As will appear from Fig. 4, the magnets 13 can be placed at suitable intervals across the screening surface, such that the magnets can be used for retaining the stif-fening elements 3 of two juxtaposed screen elements.
The use o~ magnetic retention means makes mounting and dismounting much simpler than in known mounting systems.
With magnets, the magnetic force can be used as the only retention force, but it is also possible to utilize the above-mentioned deformation of the screen elements to produce a more powerful holding~down action.
The invention has been described above with refe-rence to a screen frame in which *he screening cloth elements extend from one side to the other. However, the invention may be used also with screening machines designed in a different manner, in which the screening deck is divided into two or more juxtaposed areas, as shown in Fig. 7.
':
The present invention relates to a screen compris-ing a screen frame with supporting elements for a screen deck inserted in the screen frame, and fastening means for the screen deck.
Many different fastening methods have been used in the mounting of screens for dynamic screening machines.
According to, for example, DE-OS 2,849,838 published September 13, 1979 - Hein L~hm~nn AG, a snap-on system has been used in which the separate screen elements have been snapped onto enlarged supporting elements. Similar modes of fastening are utilized in DE-GM 78 38 335 pub-lished April 5, 1979 - Gummi-Kueper GMBH and Co. KG and DE-OS 2,749,489 published June 1, 1978 - Binder and Co.
In some cases, fastening has been accomplished by pro jections on the underside of the screen cloths and ex-pansion means adapted to urge said projections into engagement with recesses provided in the supporting elements of the screen frame. Such constructions are shown in, for example, U.S. patent specification 4,141,821 issued February 27, 1979 - Steinhaus GMBH and also in U.S. patent specification 3,745,736 issued July 17, 1973 - A. Fisher et al.
However, the above-mentioned screening machines with small individually fastenable screen elements are not often used since they necessitate reconstruction of existing screening machines. The most commonly used variant of screening machines makes use instead of screen cloths oP substantial size, very often 1-2 m2 per unit.
This type of screen cloths are fastened in the screen frames by providing the screen cloth units with hooks by which the screen cloth units are clamped between opposed edges of the screen frame. An example of such a clamping method is disclosed in DE-OS 2,005,376, published August 19, 1971 - Gummi-Kueper GMBH and Co. KG.
This fastening method is utilized for the majority .~
B
~20;2~0Z
of all screening machines which at present are manufactured all over the world, as a result oE which the frame con-structions of most screening machines are of a similar kind. As will appear from some of the above-mentioned publications, it has been tried to divide the screen deck into smaller units which are readily exchangeable to facilitate rapid exchange o a worn section and also to afford an opportunity for rapidly shifting from one hole size to another within a section of the screen deck.
The disadvantage of known smaller screen elements is that the frame construction of the screening machines used on the market must be redesigned or completed be-fore the readily exchangeable screen element systems according to, for example, DE-OS 2,754,374 published June 13, 1979 - Gummi-Kueper GMBH a~d Co. KG can be utilized.
It is one object of the present invention to pro-vide a far-reaching simplification of prior art screen constructions with smaller screen elements and to allow of a simpler and cheaper mounting on location, without necessitating any essential alteration of the frame construction of the screening machine.
According to the present invention, it is re~uired in a screen comprising a screen frame with supporting ~ID~Z
elements for a screen deck mounted in the screen frame and fastening means for the screen deck, that the said screen deck comprises several elongated screen elements placed adjacent each other and havin~ stiffening ele-ments which are included in the screen elements and which, upon mounting in the screen frame, are prestress-ed against the supporting elements by elastic deforma-tion.
The invention thus is based on the idea that the separate screen elements forming said screen deck should be formed as elongated and rigid plank-like elements and, upon m~unting, be subjected to an elastic deforma-tion in order to provide the required holding-down force against the supporting elements of the screen frame.
Compared with the conventional systems where the separate screen cloths are provided at their edges with retention hooks by which the cloths are prestressed, the present invention makes it much easier to apply the requisite holding-down force against the supporting elements of the screen frame. Thus~ if the screen frame is designed in such a manner that the supporting ele-ments force the screen elements to curve convexly, the screening elements can be formed with straight stif-fening elements. One end of the screen elements is then secured to the frame, and the screen elements are bent over the supporting elements to be secured underneath a hold-down rib at the opposite side of the screen frame. The force required for bending the screen ele-ments will be considerably less than a force directedin the plane of the screen elements and applied in order to stretch the screen elements to such an extent that the same holding-down force is obtained.
The screening system according to the invention can be utilized not only for screening machines in which the screen decks are curved convexly, but also in screen-ing machines with planar decks~ In such a case, it is possible, according to a development o~ the invention, to plastically deform the stiffening elements in a di-rection opposite to the elastic deformation to which the stiffening elements are subjected during mounting of the screen elements in the screening machine. In the present invention, it is best if the stiffening elements~ when the screen elements are mounted in the screen frame, are subjected to an elastic deformation whose spring-back force resultant is at least as large as an inertia resultant acting on the screen elements in the opposite direction, when the screen elements are used in a dynamic screening machine. If it should be difficult ko obtain such a strong elastic deforma-tion, it is possible, according to the present inven-tion! to increase the holding-down force by utilizing permanent magnets which preferably are mounted in the supporting elements of the screen frame and which are caused to act against magnetic inserts in the screening cloth. These magnetic inserts may consist of the said sti~fening elements.
~IL2~;~6~
The present invention therefore provides a screening system comprising a screen frame with supporting elements for a screen deck inserted in the screen frame, and fast-ening means for the screen deck which comprises several screen elements placed adjacent each other and having screen stiffening means consisting of stiffening elements which are included in the screen elements and which are pre-stressed against the supporting elements by elastic deformation upon mounting in the screen frame, wherein the screen elements each have a length to width ratio of at least 3:1, and wherein the stiffening elements are mounted in the screen frame with an elastic deformation whose spring-back force resultant is at least as large as an inertial force resultant acting on the screen deck in a direction opposite to the spring-back force resultant when the screen deck is used in a dynamic screening machine.
In a preferred embodiment the screen elements have a length to width ratio of at least 4:1, preferably at least 5:1. By this arrangement, the stiffening elements will lie closer to one another, and thus the total holding-down force will be greater, without it being necessary, upon mounting of the individual elements, to exert an inconven-iently great force on the free ends of the elements when they are bent down and mounted in the screen frame.
In a still further embodiment the stiffening elements are mounted in the screen frame with an elastic deformation whose spring-back force resultant is at least as large as an inertial force resultant acting on the screen deck in a direction opposite to the spring-back force resultant when the screen deck is used in a dynamic screening machine.
~92602 I~ permanent magnets are utilized for providing or lmproving tne holding-down force, these magnets should be disposed on the supporting elements of the screen frame, preferably by being connected therewith via elas-tlc dampers.
The invention will be described in more detail in the following, reference being had to the accompa-nying drawings ln which Fig. 1 is a perspective view of an example of a screen element in accordance with the present invention;
Fig. 2 is a perspective view of parts of the screen frame of a screening machine to illustrate ~he mounting of the screen elements;
Fig. 3 is a perspective view of another embodiment o~ a screen element according to the present invention;
Fig. 4 is a longitudinal section oE a part of a screening machine with screen elements accorairlg to a further embodiment of the invention;
Fig~ 5 is a section along line V-V in Fig. 4; and Fig. 6 is a section along line VI-VI in Figl 4;
Fig. 7 is a transverse section through a further embodiment of the screening system where the screening deck is divided into two juxtaposed areas.
Fig. 1 shcws a screen element consisting of an elastomer~ for instance natural or synthetic rubber~
such as polyurethane. The screen element has holes 2 made during the manufacture of the element. Reinforcing or stiffening elements 3 are insertea along the longi-tudinal sides of the screen elementO These reinforcing elements are made of rigid material and may consist of metallic square tubes~ as illustrated in the draw-ings. If necessary, the screen elements may also bereinforced with a suitable number of laid-in stiffening elements 4 extending at right angles to the stiffening or reinforcing elements 3. The screen element is then formed for overlap jointing by being provided with a recess 5 at one long side and an overlap flange 6 at the other long side.
Fig. 2 shows an example of a screen frame in a screening machineO The screen frame has side members 7, hold-down ribs 8 and longitudinal supporting elements 9. The side members 7 also are provided with supporting surfaces 10. In the embodiment illustrated, the support-ing surfaces 10 and the supporting elements 9 are mount-ed at different levels, such that the screen elements 1 will curve upwardly over the supporting elements 9.
As will appear from Fig. 2, the screen elements are mounted by ~lamping their one ends against the sup-porting surface 10 by means of the hold-down rib 8, whereupon the elements are pressed down over the sup-porting elements 9 by being subjected to a force in the direction of the arrow 11. Finally, the elements 1 are retained in this elastically deformed position by securing the hold-down rib 8 to the left in Fig. 2.
The present invention thus utilizes the elasticity or spring ~orce provided by the stiffening elements 3 in order to obtain the requisite holding-down action against the supporting elements 9 during the subsequent use of the screening machine. The holding-down action ~20,~0~
can be very large if an appropriate material is select-ed for the stiffening elements 3. These elements may consist of, for example, metallic material which is rigid and can be subjected to heavy elastic deformation without surpassing the 0.2~ yield strength during mount-ing. However, the stiffening elements 3 may also be formed of other materials, such as glass fiber rods or other rigid bars placed in the screening cloth ele-ments either at the long side edges only, as is shown in Fig. 1, or at suitable intervals in the lateral di-rection of the screen elements (= the screening direc-tion of the screQning machine).
In the embodiment according to Figs. 1 and 2, the invention has been utilized in connection with a screen-ing machine with a convexly curved screen deck. As has been mentioned above, the invention may also ~e utilized with screening machines in which the finished screen deck i5 planar, in which case the stiffening elements may have been subjected to a plastic predeformation (see Fig. 3) such that the screen elements are curved in à direction opposite to the elastic deformation im-parted to them during mounting. In Fig. 3, this plastic predeformation is illustrated by the arrows 12 which indicate the amount by which the screen elements de-viate from a straight line 13.
If it is desired, according to a further development of invention, to strengthen the holding-down force or to avoid deformation of the screen elements during mount-ing, it is possible in accordance with Figs. 4-6, to pro-~0~
vide a holding-down force by means of permanent magnets 13 which, by means of resilient holders 14 serving as dampers, are mounted on the longitudinal supporting elements 9 of the screen frame. In the embodiment illu-strated, the holders 14 are fi~edly mounted on the lon-gitudinal supporting elements 9 by means of a holder plate 15 secured by means of bolts 16 (Fig. 5) or by welding (Fig. 6).
The permanent magnets 13 attract the stiffening elements 3 which are inserted in the screen elements and which, in this instance, must consist of magnetic material to be able to function as armatures. As will appear from Fig. 4, the magnets 13 can be placed at suitable intervals across the screening surface, such that the magnets can be used for retaining the stif-fening elements 3 of two juxtaposed screen elements.
The use o~ magnetic retention means makes mounting and dismounting much simpler than in known mounting systems.
With magnets, the magnetic force can be used as the only retention force, but it is also possible to utilize the above-mentioned deformation of the screen elements to produce a more powerful holding~down action.
The invention has been described above with refe-rence to a screen frame in which *he screening cloth elements extend from one side to the other. However, the invention may be used also with screening machines designed in a different manner, in which the screening deck is divided into two or more juxtaposed areas, as shown in Fig. 7.
':
Claims (4)
1. A screening system comprising a screen frame with supporting elements for a screen deck inserted in the screen frame, and fastening means for the screen deck which comprises several screen elements placed adjacent each other and having screen stiffening means consisting of stiffening elements which are included in the screen elements and which are pre-stressed against the supporting elements by elastic deformation upon mounting in the screen frame, wherein the screen elements each have a length to width ratio of at least 3:1, and wherein the stiffening elements are mounted in the screen frame with an elastic deformation whose spring-back force resultant is at least as large as an inertial force resul-tant acting on the screen deck in a direction opposite to the spring-back force resultant when the screen deck is used in a dynamic screening machine.
2. A screening system according to claim 1, wherein the length to width ratio of the screen elements is at least 4:1.
3. A screening system according to claim 1, wherein the length to width ratio of the screen elements is at least 5:1.
4. A screening system according to claim 1, 2 or 3, wherein the stiffening elements are mounted in the screen frame with an elastic deformation whose spring-back force resultant is at least as large as an inertial force resultant acting on the screen deck in a direction opposite to the spring-back force resultant when the screen deck is used in a dynamic screening machine.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE8107293-6 | 1981-12-07 | ||
| SE8107293 | 1981-12-07 | ||
| SE8201272A SE428763B (en) | 1981-12-07 | 1982-03-02 | Arrangement for a screen |
| SE8201272-5 | 1982-03-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1202602A true CA1202602A (en) | 1986-04-01 |
Family
ID=26658032
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000416949A Expired CA1202602A (en) | 1981-12-07 | 1982-12-03 | Screening system |
Country Status (11)
| Country | Link |
|---|---|
| EP (1) | EP0081471B1 (en) |
| JP (1) | JPS58502040A (en) |
| AT (1) | ATE28414T1 (en) |
| AU (1) | AU554492B2 (en) |
| CA (1) | CA1202602A (en) |
| DE (1) | DE3276789D1 (en) |
| DK (1) | DK151461C (en) |
| ES (1) | ES517937A0 (en) |
| FI (1) | FI73901C (en) |
| NO (1) | NO156438C (en) |
| WO (1) | WO1983002075A1 (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3628418A1 (en) * | 1986-08-21 | 1988-02-25 | Krupp Gmbh | Screen with exchangeable screen lining |
| US5586661A (en) * | 1994-12-15 | 1996-12-24 | Illinois Tool Works Inc. | Dam member for a screen deck |
| BR9500893A (en) * | 1995-02-24 | 1997-04-29 | Aco Paulista Sa | Modular vibrating screen |
| US5755334A (en) * | 1996-03-19 | 1998-05-26 | Illinois Tool Works Inc. | Method and apparatus for mounting a panel on a support member |
| AUPQ012999A0 (en) * | 1999-05-03 | 1999-05-27 | Usf Johnson Screens Pty Ltd | Screening equipment |
| US7922003B2 (en) * | 2006-09-29 | 2011-04-12 | M-I L.L.C. | Magnetic screen clamping |
| CN102873025A (en) * | 2012-09-29 | 2013-01-16 | 山东润科机电设备有限公司 | Vibrating screen |
| CN113893599B (en) | 2020-07-06 | 2022-07-01 | 河北冠能石油机械制造有限公司 | Vibrating screen mesh for a shale shaker |
| EP4176981A1 (en) * | 2021-11-09 | 2023-05-10 | Steinhaus GmbH | Magnetic screen bottom attachment system with automatic positioning |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2910180A (en) * | 1955-03-07 | 1959-10-27 | Tyler Co W S | Screen deck structure |
| NL138604C (en) * | 1968-09-25 | |||
| JPS4915993Y1 (en) * | 1969-05-16 | 1974-04-22 | ||
| JPS5521037B1 (en) * | 1971-03-23 | 1980-06-06 | ||
| DE2461237C3 (en) * | 1974-12-23 | 1980-01-24 | Hein, Lehmann Ag, 4000 Duesseldorf | Tensionable, elastic sieve bottom |
| AT344629B (en) * | 1976-05-21 | 1978-08-10 | Steinhaus Gmbh | SIEBFELD |
| US4120784A (en) * | 1976-06-16 | 1978-10-17 | N. Greening Limited | Screening apparatus |
| DE2754374A1 (en) * | 1977-12-07 | 1979-06-13 | Kueper Gummi | Screen for screening or sifting machine - has interlocking tongue edge panels which can be replaced in sections when worn |
| DE2932696A1 (en) * | 1979-08-11 | 1981-02-19 | Heinz D Gaertner Gmbh | Sieve bottom for tied or loose sieve plates - has tie rods through plate ribs to support rails |
| JPS6018525Y2 (en) * | 1979-09-04 | 1985-06-05 | 不二サッシ株式会社 | Pulling device at the end of the sliding door |
-
1982
- 1982-11-29 WO PCT/SE1982/000406 patent/WO1983002075A1/en active IP Right Grant
- 1982-11-29 AT AT82850244T patent/ATE28414T1/en not_active IP Right Cessation
- 1982-11-29 JP JP83500031A patent/JPS58502040A/en active Pending
- 1982-11-29 EP EP82850244A patent/EP0081471B1/en not_active Expired
- 1982-11-29 DE DE8282850244T patent/DE3276789D1/en not_active Expired
- 1982-11-29 AU AU10160/83A patent/AU554492B2/en not_active Ceased
- 1982-12-03 CA CA000416949A patent/CA1202602A/en not_active Expired
- 1982-12-06 ES ES517937A patent/ES517937A0/en active Granted
-
1983
- 1983-04-25 NO NO83831442A patent/NO156438C/en unknown
- 1983-05-11 FI FI831639A patent/FI73901C/en not_active IP Right Cessation
- 1983-06-16 DK DK278683A patent/DK151461C/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| NO831442L (en) | 1983-06-23 |
| ES8308232A1 (en) | 1983-08-16 |
| EP0081471B1 (en) | 1987-07-22 |
| DK151461C (en) | 1988-05-30 |
| AU554492B2 (en) | 1986-08-21 |
| FI73901C (en) | 1987-12-10 |
| WO1983002075A1 (en) | 1983-06-23 |
| ES517937A0 (en) | 1983-08-16 |
| DE3276789D1 (en) | 1987-08-27 |
| FI831639A0 (en) | 1983-05-11 |
| FI831639L (en) | 1983-06-08 |
| FI73901B (en) | 1987-08-31 |
| NO156438B (en) | 1987-06-15 |
| NO156438C (en) | 1987-09-23 |
| DK151461B (en) | 1987-12-07 |
| DK278683A (en) | 1983-06-23 |
| EP0081471A1 (en) | 1983-06-15 |
| ATE28414T1 (en) | 1987-08-15 |
| DK278683D0 (en) | 1983-06-16 |
| JPS58502040A (en) | 1983-12-01 |
| AU1016083A (en) | 1983-06-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |