GB2073618A - Vibratory screening panels - Google Patents

Abstract

A plurality of truss-beam supports are secured, as by welding, and in spaced relationship, to the underside of a screen cloth (14). The supported screen cloth is then removably secured in position in a vibrating frame (12) to form therewith a vibrating screen. Each truss-beam support includes a support rod (90) formed of wire rod of predetermined diameter disposed with a major portion thereof spaced from and substantially parallel to the plane of the screen cloth, and with end portions (94, 96) thereof merging into the plane of the end pieces of selected wire rods forming the screen cloth and being welded thereto. A spacer wire (100) formed from wire rod of a diameter less than that of the support rod and to an approximate sinusoidal configuration, is disposed so that the upper tips, formed by the sine configuration, are welded to the bottom surface of the screen cloth and so that the lower such tips are welded to the upper surface of the support rod. <IMAGE>

Description

SPECIFICATION Vibrating screen and screen cloth therefor This invention relates to vibrating screens and screen cloth for vibrating-screens for bulk material processing.

Vibrating screens find many uses in many diverse industries and applications. Their general purpose is to separate by size bulk material placed upon the screen wherein the constituent makeup of the bulk material includes elements which vary in size.

Where the constituent elements making up the bulk material include cbmponents like rock, aggregate or the like, that do not have sticky surface characteristics and therefore do not include lumps of pieces that are stuck together, the vibrating screen merely separates the.

components by size. The- pieces too large to pass through the screen opening pass over the screen deck to be collected by suitable means. The pieces that are smaller than the openings pass therethrough and are either collected at the next lower lever or are again separated by size by another level of screening.

However, some bulk materials, for one reason or another, may have to be processed even though its surfaces are sticky. The sticky surfaces may be natural to the bulk material or it may result from a particular process undergone by the material. No matter what, it may be desirable to utilize the screening function to break up the lumps of stuck together material into their individual pieces in addition to separating such pieces by size. If the pieces when so separated are essentially of uniform size then the screening function is merely to break up the lumps.

Some available vibrating screens utilize perforated plates for the screen deck (screening element). However, these have been found generally unsatisfactory because the interaction between the relatively smooth surfaced deck and the stuck together lumps does not provide as effective a separation of the lumps as is required and/or desired in many applications.

Other vibrating screens utilize screen cloth because the nodules or peaks, formed by the intersecting wire rods, present an irregular surface to the lumps of stuck together material and help abrade and separate same. However, in many applications the lack of rigidity of the installed screen cloth has proved to be detrimental to screen cloth life and has resulted in excessive down time.

Crowning (i.e. upwardly convex arching) of the screen cloth to impart some degree of rigidity to the installed deck while improving that aspect of the installation usually results in a migration of the screened material to the sides of the screen. This hinders collection of the screened material and often results in a disproportionate wear of the side plate and left and right side screen frame components.

Other attempts to providing a more rigidly installed screen deck involve fabricating the screen frame itself so as to be in contact with and to support the wire cloth with the cloth welded to such screen frame. In equipment so constructed when the screen cloth wears out, as it will eventually do, the separation of the welded joints is often so time consuming or impossible that a new screen frame and possibly a new screen may be the less expensive alternative.

In accordance with the present invention, there is provided a screen panel for use in a vibrating screen -- comprising a perforated screen cloth and a support member arranged beneath the screen cloth and secured thereto to support the cloth in a rigid manner.

The invention also includes a vibrating screen incorporating such a screen cloth.

A presently preferred form of vibrating screen and screen cloth in accordance with the invention will now be described in detail with reference to the accompanying drawings in which: Figure 1 is a perspective view of the vibrating screen; Figure 2 is a section across the width of the vibrating screen of Figure 1; Figure 3 is an enlarged vertical section of the left side of the installed screen cloth of Figure 2; Figure 4 is a vertical section of the left side of the screen cloth of Figures 2 and 3 showing it uninstalled; Figure 5 is a top plan view of an end section of the uninstalled screen cloth; Figure 6 is a vertical end view of the uninstalled screen cloth of Figures 4 and 5; and Figure 7 is an enlarged sectional view of one wire rod of the screen cloth of Figures 4 to 6 showing details of its support assembly.

For convenience the invention will be described as applied to a vibrating screen having a pair of horizontally disposed spaced screen decks each including a single screen panel and all of which being supported by a vibrating frame that is spring-mounted on cement pads, and wherein the vibrating mechanism is mounted across the width of the screen and over the top of the upper screen deck, it should be understood, nevertheless, that without departing from the scope of this invention, the vibrating screen may have only one deck or two or more than two decks, that each deck may include any desired and appropriate number of screen panels, that the frame need not be horizontally disposed or spring mounted on cement pads as long as other suitable mounting means are provided, and that the vibrating mechanism can be positioned other than across and over the top screen deck as long as it is disposed to yibrate the frame and screen decks in arWåppropriate manner.

With reference to Figures 1 and 2, there is generally shown at 10 a vibrating screen including a spring mounting vibrating frame assembly 12 a pair of spaced screen deck assemblies 14, 1 6 (Figure 1) and a vibratory mechanism assembly 1 8 supported on and spanning vibrating frame assembly 12.

Vibrating or live frame assembly 12 includes a pair of spaced side plates 30, 32 spanned by and freely secured together by a plurality of support frame members 34 (only one shown in Figure 2).

Channel members 36, and other appropriately fabricated and suitably positioned members complete vibrating frame assembly 12 in substantially conventional manner.

A plurality of spring assemblies 40 facilitate the mounting of vibrating screen 12 on cement pads 42, it being understood that other suitable means such as pedestals (not shown) may be used for this purpose.

The vibratory mechanism 18 is of conventional construction and is conventionally mounted across the top of and between side plates 30, 32.

When connected to a suitable means of motive power and through suitable controls mechanisms 1 8 will impart vibrations to vibrating frame assembly 12 of predetermined characteristics to vibrate frame assembly 12, screen decks 14. 16, and any material disposed thereupon.

Screen decks 14, 16 each include a single screen panel assembly 50 (Figures 2 to 6) sized to span the space between side plates 30, 32 and to extend the length of vibrating screen 10. Each deck 14, 1 6 may however, just as easily consist of a plurality of screen panels sized to span the space between sideplates 30, 32 but each being shorter than the length of screen 12, the number of such panels being selected to provide a screen deck of appropriate length. In either instance 'the construction of each screen panel assembly 50 will be substantially identical.

Each screen panel assembly 50 includes a screen cloth section 52 fabricated in substantially conventional manner from a plurality of wire rods 54, 56 predetermined size and cross sectional configuration. Rods 54, from side to side across the width of screen 10 and are spaced from each other and secured as by welding to rods 56 which extend front to back (in the direction of material flow) and are also spaced from each other The spacing between rods 54, 56 is determined by the size of the desired screening openings 60. The weaving process for screen cloth 50 creates bumps or nodules 62 which coact with lumps of material 66 (Figure 2) when disposed upon vibrating screen deck 14 to abrade same and facilitate separation of such lumps 66 into its individual particles 66a, 66b etc.

A plurality of truss-like screen cloth support assemblies (or truss beams) 70 (Figures 2, 4 and 6) and 72, 74, 76, 78, 80 (Figure 6) are secured (as by welding) to the underside of screen cloth section 52 to impart rigidity-thereto and render same self-supporting. Each assembly 70-80 includes a support rod 90 (Figures 2, 4, 6 and 7) of predetermined diameter extending the width of screen cloth section 52. A major portion of rod 90 is formed so as to be spaced from the underside of screen cloth section 52. End portions 94 (Figure 2) and 96.(Figures 2 4, and 7) of rod 90 are formed to bend upwards and into the plane of screen cloth section 52.The extreme ends 98 of each support rod 90 are bent soyas to lie in the plane of the ends of wire rods 54 of screen cloth section 52; and are each disposed adjacent selected ones of such rod ends (see Figures 5 to 7) and are secured thereto as by welding.

A support wire 100 (Figures 2M4) is formed into a substantially sinusoidal configuration within the upper tips 102 (Figure 3) thereof spaced from the lower tips 104 so as to fill the space between the -lower surface of screen cloth section 52 and an upper surface 106 of support rod 90. Support wire 100 is secured in position by welding or otherwise suitably attaching tips 102 to the wires of screen cloth section 52, and alternate tips 104 to surface 106 of rod 90.

An end piece 110 (Figures 3, 4 and 6) secured atop and to- each side of screen cloth section 52, to facilitate its installation into frame assembly 12, completes screen panel assembly 50.

A ledge 120 (Figures 2 and 3) is secured to the inside wall of each side plate 30, 32 so as to run the length thereof and to receive the ends of each screen panel assembly 50. Once a screen panel assembly 50 is disposed a top ledge 120 it is secured in position-by one or more clamp block assemblies 1 22 (Figure 3) of substantially conventional configuration and operation. If desired a wear plate T24 may be disposed as shown in Figure 3 to protect the elements of clamp block assembly 122 from the accumulating and possibly abrasive effects 9f the material to be screened.

Each screen panel assembly 50 is thus of rigid construction with its screen cloth section 52 substantially self supported, due to truss like assemblies or truss beams 70-80 and so supported in substantially a horizontal plane.

Installation and removal of such screen panel assembly or assemblies 50 in vibrating frame assembly 12 is easily accomplished as described hereinabove. When so installed material deposited in lumps 66 on top of screen deck 14 will be vibrated, due to the coaction of vibrator 18, vibrating frame 12 and deck 14, and will coact with screen cloth 52 and its nodules 62 to be separated and sifted into its component particles 66a, 66b etc. If desired screen 10 can include material flow shelves 120' appropriately secured to side plates 30, 32 to direct the flow of the sifted and sorted material From the above description it will thus be seen that there has been provided a novel and improved apparatus for sorting and sifting bulk material; which apparatus incorporates a substantially selfsupported screen cloth disposed between the side plates of a vibrating frame to form therewith a vibrating screen with screen cloth decks supported in a rigid and substantially horizontal disposition.

Claims (14)

1. A screen panel for use in a vibrating screen comprising a perforated screen cloth and a support member arranged beneath the screen cloth and secured thereto to support the cloth in a rigid manner.

2. The screen panel of claim 1 wherein the support member is formed as a truss-beam comprising a support rod having a major portion thereof spaced from the under surface of the screen cloth and further having end portions directed towards the screen cloth, the extremities of said end portions being secured to respective opposed edges of the s.creen cloth, and support wire means formed into a substantially sinusoidal configuration with the tips thereof secured in contact with the under surface of the screen cloth and the support rod, respectively.

3. The screen panel of claim 3, comprising a plurality of said support means the said trussbeams spaced from each other.

4. The screen panel of claim 2 or 3 wherein the or each truss beam is disposed to lie across the width of the screen cloth.

5. The screen- panel of claim 2, 3 or 4 wherein the said support rod and the support wire means are secured to each other by welding;

6. The screen panel of any preceding claim, wherein the screen cloth is formed by a woven assembly of rod-like members.

7. The screen panel of claim 6 wherein the rod like members are so woven as to form nodules or bumps where the rods cross each other, to give the screen cloth an irregular surface.

8. The screen panel of any one of claims 2 to 5 wherein the said extremities of the end portions are secured to the end portions of respective said rod-members.

9. A vibrating screen comprising a live frame, at least one screen panel in accordance with any preceding claim, and a vibratory mechanism to effect vibration of the frame and panel.

1 0. The vibrating screen of claim 9, wherein the frame supports the screen panel in a substantially horizontal position.

11. The vibrating screen of claim 10 comprising a plurality of screen panels arranged at different levels.

12. The vibrating screen of claim 9 or 10 comprising a plurality of the said screen panels.

1 3. A screen panel substantially as herein described with reference to the accompanying drawings.

14. A vibrating screen incorporating at least one screen panel in accordance with claim 13.