US2247271A - Screen and means for preventing blinding thereof - Google Patents

Description

R. BARLOW 2,247,27M

SCREEN AND MEANS FOR PREVENTING BLINDING THEREOF June 24, 1941'.

Filed Jan. 6, 1940 2 Sheets-Sheet 1 June 24, 1941. BARLOW 2,247,271

SCREEN AND MEANS FOR PREVENTING BLINDING THEREOF Filed Jan. 6, 1940 2 Sheets-Sheet 2 Patented June 24, 1941 error f SCREEN AND S FQRPREVENTING BLINDING THEREOF Richard Barlow, Milwaukee, ,,-Wis., .assignor to NordbergjManufacturing.Company, Milwaukee, Wis., a corporation'of Wisconsin Application-January 6, 1940, Serial -No.31'2,669

. 3 Claims.

My invention relates to-an improvement in screens-and has for one purpose-the provision of means for preventing the blinding of screen mesh.

Anotherpurpose is the provision-of meansfor independently vibrating-the mesh of a vibrated screen, whereby, in addition'to the normal-conveying and separating vibration'of'the screen, an additional *cleansing or anti-blinding vibration may be imparted to the mesh. I

Other purposes will appear from timeto time in th course of'the specificationfand claims.

PIiIIustrate my invention more orless-diagram- .matically in the accompanying drawings .wherein:

Fig. 1 is' a longitudinalsection;

Fig.2 is a section on an enlarged-'scalezon'the line 2-2 of Fig. 1;

Fig.3 is a'section on anenlarged: scale on the line 33 of Fig.

Fig. '4 is a section on an enlarged scale on the line 44 of Fig, 3; and

Fig. 5 is a section on an enlarged scale on the line 5-5 of Fig. 2.

Like parts are indicated by like symbols throughout the specification and drawings,

Referring to the drawings, l, 2 indicate longitudinally extending, generally parallel base frame members, which may be connected by one or more transverse connecting members 3. 4 generally indicates a screen deck, the details of which do not of themselves form part of the present invention. The deck, however, may include side plates 5, 6, transversely extending supports 1, longitudinally extending frame members 8, and upwardly open channels 9 extending longitudinally along the deck.

The deck as a whole may be mounted on the base by any suitable flexible leaf spring structures l2, the details of which do not form part of the present invention. Spring means I3 may be employed tending to hold the deck structure at a predetermined neutral position, with the springs l2 unflexed. Side weight bars M are illustrated as mounted on similarly inclined leaf springs l5. It will be understood that the bars I4 extend from end to end of the base and that any suitable feed member 16 may be mounted upon the bars.

Also mounted upon the ends of the bar at the right end, when the parts are in the position of Fig. 1, is any suitable vibrating element, the details of which do not form part of the present invention, but which is indicated diagrammatically as at 11. The vibrating element may be connected to the deck as by horizontally extending leaf springs l8.

The description of the particular'screen shown will be understood as merely illustrative,.-.since the present invention may be appliedto anyuone -of anumber of screens and is not dependentupon the details of the particular screen employedpr on the means employed for vibrating the screen or screen deck. It will be understood however, that some suitable mesh or screen :cloth r20 is properly stretched upon a screen deck and is herein shown 7 as resting upon the. tops of -rubber strips or members 2! mountedin the channels .9. Any suitable clamping means :22 may beem- .ployed for transversely tensioning theimeshizll, :and similarly, any suitable end tensioningl-means not herein shown may be employed.

Secured to or mounteduponxthamcshitseliis :an .additional vibrating structure. =I illustrate diagrammatically forvexample. any suitablapneumatic vibrator, the detailscofywhich, aremot; illustrated but which isshown at 25.

It may bebo11- nected as by any suitable flexible conduit 26, with a supply of fluctuating pneumatic pressure. Any suitable valve 21 may be employed between the source of pressure and the vibrator 25. It will be understood that, in response to the supply of pressure, the vibrator 25 is caused to vibrate, and with it to vibrate any parts attached thereto.

It will be understood that, whereas I have illustrated two of said vibrators, as in Fig. 1, a larger or a smaller number may be employed, depending upon the length or area of the screen and the service for which the screen is employed.

In order to transmit the vibration of the vibrator 25 to the screen mesh I illustrate a transversely extending member 30, secured to each said vibrator, as at 3|. It may be secured to the mesh itself by the intermediary of spacing sleeves 32 and washers 33, 34, engaging the upper and lower faces of the screen mesh 20. Any suitable securing means, such as the hook bolt 35, with its nuts 36, may be employed to hold the member 30 against the upper ends of the sleeves 32, and also to lock the lower ends of the sleeves 32 to the mesh. Thus when a vibrator 25 is vibrated, the vibration is transmitted to the mesh 20 itself. This vibration has no conveying effect on the material going over the screen and is in addition to the normal vibration of the screen which is obtained by rotation of the vibrating member l1 above alluded to. Since the conduits or pipes 26 are flexible, the normal screening vibration of the screen is not interfered with by the connections between the source of pneumatic pressure and the vibrators 25.

It will be realized that whereas I have deand stay there.

,blinding particles. be constantly applied, or it may be intermittently 1 ;applied when conditions call for it.

scribed and illustrated a practical and operative device, nevertheless many changes may be made in the size, shape, number and disposition of parts without departing from the spirit of my invention. I therefore wish my description and drawings to be taken as in a broad sense illustrative or diagrammatic, rather than as limiting me to my precise showing.

The use and operation of my invention are as follows:

In screening, and particularly wet screening, the screen mesh not infrequently tends to blind. This blinding may result from the application of sticky material to the screen, or it may result from the shapes of the particles. A frequent cause of blinding is the passage of wedge-shaped or cone-shaped particles or slivers across the screen. A particle which is long and narrow,

and which may have for example a sharp point, may become wedged in an aperture in the mesh The conveying vibration, it will be understood,

is at a substantial angle from the vertical and .may, in fact, be almost or entirely horizontal in some types of screens at some part of the screen surface.

The pneumatic vibrator above described may be. employed to impart to the mesh itself, in addition to the screening vibration, a generally vertical vibration, which causes the particles to .dance on the screen mesh and which in practice proves highly effective in preventing the mesh from blinding, or in freeing blinded mesh from This additional vibration may It will be understood also that a pneumatic or :supplemental vibrator may be employed to subject the mesh to vibration at a substantial angle gto the vibration imparted to the deck by the main deck vibrating means, and also at a different frequency. Preferably the vibrations are of higher frequency. The additional vibrator may be employed intermittently to clear the screen, or, if desired, it may be employed continuously or substantially continuously in order to increase the screening capacity of the screen.

I claim:

1. In a screen structure, a screen deck and means for imparting a screening vibration thereto, screen mesh on said deck, and additional means for imparting an additional vibration to said mesh, said additional means including a pneumatic vibrator and means for actuating it, said pneumatic vibrator being supported upon the screen mesh.

2. In a screen structure, a screen deck and means for imparting a screening Vibration thereto, screen mesh on said deck, said screen including mesh supporting members extending beneath said mesh, and'additional means for imparting an additional vibration to the mesh, including a pneumatic vibrator supported on and connected to the mesh itself in an unsupported mesh area, a source of pneumatic pressure, and a flexible actuating connection between said source and said vibrator.

3. In a screen structure, a screen deck and means for imparting a screening vibration thereto, screen mesh on said deck, said screen including mesh supporting members extending beneath said mesh, and additionalmeans for imparting an additional vibration to the mesh, including a frame secured directly to unsupported portions of the mesh at a plurality of points, a pneumatic vibrator mounted on said frame, a source of pneumatic pressure, and a flexible actuating connection between said source and said vibrator.

RICHARD BARLOW.

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