US2308572A - Rod screen - Google Patents

Description

L. G. SYMONS Jan. 19, 1943.

ROD SCREEN led May 9; 1940 I r m 5 r n n I n .i

iiarweya jyezezar .Zarezz airy/720w; y M M Patented Jan. 19, 1943 ROD SCREEN Loren G. Symons, Hollywood, Calif., assignor to Nordberg Manufacturing Company, Milwaukee, Wis, a corporation of Wisconsin Application May 9, 1940, Serial No. 334,141

16 Claims.

The invention relates to an improvement in screens, particularly of the bar or rod type.

One purpose is the provision of an improved rod for such screens.

Other purposes will appear from time to time in the course'of the specification and claims.

The invention is illustrated more or less diagrammatically in the accompanying drawing wherein:

Fig. 1 is a verticallongitudinal section through a rod screen illustrating the invention;

Fig. 2 is a partial longitudinal section illustrating the insertion of a rod;

Fig. 3 is a section on the line 3--3 of Fig. 2;

Fig. 4 is an enlarged section on the line 4-4 of Fig. 2; and

Fig. 5 is a detail section through a part of the device.

Like parts are indicated by like symbols throughout the specification and drawing.

Referring to the drawing, I indicates a side frame member, it being understood that a pair of parallel side frame members may be employed to constitute or form part of the screen deck. The deck as a whole may be vibrated in any suitable manner, for example by the unbalanced rotor generally shown at 15. The deck includes a plurality of transversely extending frame members, including, for example, angles 2, 3 at the ends of the deck, an angle 4 interbers 9, H) are arranged back to back on the angles 4. Other channel members ll, upwardly concaved, are mounted on the tops of the intermediate supports 5.

I find it practical to arrange the deck with a plurality of panels, each such panel being formed to receive a plurality of rods l2, which will be later described in detail. The ends of the rods may be received in transversely extending rubber supports or cushions, or positioning members l3, provided with inclined spaced apertures l5, adapted to receive the ends of the rods.

The supports l3 may be received in the end channels I of the cross frame members or angles 2, at the feed end of the screen.

For the intermediate members 4 a different form of transversely extending support may be employed, which is adapted to surround both the channels 9 and I0. Such a member is illustrated at IS in Figs. 1 and 2 and includes downwardly extending flanges l1, 18, each hav- 1 ing inclined holes 20 to receive the rod ends. The face of the member I6 toward the feed end of the screen may be beveled as at 2| to permit the material going over the screen to ride readily over it, and to protect the end of the rod against excessive wear, which tends to take place where the flow of material is arrested. At the discharge end of the screen I may employ a member 22 of rubber or the like, which is similar to the member IS, with a similar inclined face 2|, but is single in that it has but one of the downwardly extending flanges l1 and is located in place as for example by the smaller downwardly extending flange 23.

I find that there is a definite relation between the length and diameter of the rods, the hardness of the rods, etc., whichis in practice exceedingly important. I find it well to employ normally straight rods of a predetermined length. I have selected as one example a standard length of 23%", which may be used for all types and sizes of screens. In order to prevent wear I find that the hardness of the rods should be not less than 300 Brinell. The ratio of rod length (L) to thickness (D) should be L/D not less than 60, and not more than 190. As an example of a table of wire sizes, I may indicate the following:

Diameter (inches) Screen opening 5%", #11 wire .12 Screen opening #8 wire .162 Screen opening #6 wire .192

Screen openings A", 1%" and #3 wire- .244 Screen openings /g", and A", #0 wire .307 Screen openings and 1", #000 wire .362

All of the above diameters are referred to a common length of 23%". This length is such that the ratio between diameter and length produces sufficient resistance to fiexure in rods as small as A3" in diameter so that they cannot be dislodged from their seats by the vibrating action of the screen.

The fiexure of the rod necessary for placing it in the screen deck is approximately 2 Rods after fiexure and before fiexure are shown in Fig. 2. It will be understood that they must be flexed in order to permit the ends to penetrate the apertures l5 or 20 of the various rubber supports and positioning members. The rods are self-locking, due to their resistance to fiexure. The material of the rod should also be such that the fiexure necessary to place it in position does not result in a permanent set or curvature of the rod. Stresses in the rod will be set up varying between 70,000 and 140,000 pounds per square inch, depending upon the diameter of the rod. This represents the approximate yield point in the material, which, if'exceeded, will result in a permanent set, but not necessarily in the failure of the material. I find it desirable, in order to permit this fiexure, to employ steel of not less then .45 carbon, and I also employ manganese in addition, for example to .60. However, there is a, substantial possible variation of carbon and manganese content.

Referring to Figs. 1 and 5, I illustrate a complete screen structure in which the rods it are illustrated as arched in individual panels A, B, C and D, and in which the individual panels A, B, C and D are set at different angles, whereby the screen is steeper at the feed end, beneath the feed spout 50, and is most close to the horizontal at the opposite or discharge end of the screen. The screen frame structure, including the side members I, is mounted upon a flexible link 5!, the details of which do not form part of the present invention. It will be understood, however, that the feed end of the screen is vibratably supported by the inclined link 5| which has a rubber pad 52 at the top thereof, and a second rubber pad 53 at the bottom thereof, the entire structure being held together, for example, by

bolts 54 and flexible rubber bushings 55. At

either side of the screen deck a spring 56, seated 30 between a frame member 51, secured to the base 62 and the screen deck, serves to cushion the movement of said screen deck and link 5|.

The opposite end of the screen deck may be supported for example by a tension member or rod 58, of which one may be located at each side of the screen, such rod having an upper washer 59 and a coil spring 60, compressed between such washer and the top SI of any suitable surrounding outside housing or base 62.

Any suitable vibration producing means, which do not of themselves form part of the present invention, are indicated as at I5, and will not be described in detail. It will be understood, however, that 15 indicates an unbalanced 45 rotor, which is unbalanced when rotated, and which may be rotated by any suitable motor not herein shown, whereby vibration is imparted to the screen structure.

The change in angle as the material travels down the inclined surface of the screen decreases the gravital feed from the feed to the discharge end of the screen and gives a quick settling action, with relative fast travel, at the feed end, and slower travel, and complete screening separation, at the discharge end.

It will be realized that, whereas I have described 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 the invention. I therefore wish the description and drawing to be taken as in a broad sense illustrative 01' digrammatic, rather than as limiting me to the precise showing.

It will be realized, for example, that the invention is not limited to a rod of specific cross sectional shape. Whereas a round rod may be convenient or preferable, a square bar or rod otherwise formed may also be employed. It will be understood also that, in place of a rod, I may employ a relatively flat member, such for example as a perforated or foraminous plate. The same factors apply.

assass n and 22, with the intermediate parts of the rods positioned in slots or concave apertures in the intermediate rubber supports 11. The rods are thus arched and held firmly in position and are laterally spaced in relation to each other, and

vibration or displacement is prevented.

The arrangement of the panels to form a convex screen, or a screen with a varying angle from the horizontal, is highly desirable. The material is fed partially by gravity along the initial or more highly inclined part of the deck, as

will be clear from Fig. 1, gravity supplementing the conveying action of the vibration of the screen in response to the rotation of the member 15. As the fines pass through the initial part of this deck, a slowing of the movement, or

a settling action, is desirable, and this is obtained by the relatively fiat angle of the discharge portion of the deck.

It will be observed that the rods I! may be uniformly spaced by their penetration in the end apertures 20, as shown in Figure 3, and also by their penetration in slots or grooves in the tops of the transverse intermediate members 'Il. Thus, once the rods are clamped in position, they are firmly locked in proper spaced relationship.

I claim:

1. A vibratory screen deck including side frame members and transverse connecting members, and a plurality of screen panels on said 40 deck, each such screen panel including a plurality of longitudinally extending wires, said wires being arched to form a transversely extending convex surface for said panel, the panels being located at different angles in relation to the horizontal and being arranged to form a generally concave screening surface, and upstanding bailles transversely extending across the screen along the abutting edges of adjacent panels, the feed face of said baflies being inclined.

2. A vibratory screen deck including side frame members and transverse connecting members, and a plurality of screen panels on said deck, each such screen panel including a. plurality of longitudinally extending wires, said wires being arched to form a transversely extending convex surface for said panel, the panels being located at different angles in relation to the horizontal and being arranged to form a generally concave screening surface, the angle of the screening surface of the deck, taken as a whole, diminishing from the feed end to the discharge end of the deck, and upstanding baflles transversely extending across the screen along the abutting edges of adjacent panels, the feed face of said baifles being inclined.

3. A screen rod formed of steel having a hardness of not less than 300 Brinell and having a ratio of length to thickness of not less than 60 and not more than 190, and a yield point sufliness of not less than 300 Brinell and having a ratio of length to thickness of not less than 60 and not more than 190, and a yield point sufllcient to permit a fiexure of not less than 2 without permanent set in a length of in the order of two feet, said rod being formed of a steel of a-carbon content of not less than 0.45 and of the general order of 0.60.

5. A generally rectilinear screen rod formed of steel having a hardness of not less than 300 Brinell and having a ratio of length to thickness of not less than 60 and not more than 19.9. and a yield point suflicient to permit a fiexure'of not less than 2 without permanent set in a length of in the order of two feet.

6. A generally rectilinear screen rod formed of steel having a hardness of not less than 300 Brinell and having a ratio of length to thickness of not less than 60 and not more than 190, and a yield point sufficient to permit a i'lexure of not less than 2%" without permanent set in a length of in the order of two feet, said rod being formed of a steel of a carbon content of not less than 0.45 and of the general order of 0.60.

7. In combination with a rod screen deck and means for vibrating it, a screen rod formed of steel having a hardness of not less than 300 Brinell and having a ratio of length to thickness of not less than 60 and not more than 190, and a yield point sufficient to permit a flexure of not less than 2 without permanent set in a length of in the order of two feet.

8. In combination with a rod screen deck and means for vibrating it, a screen rod formed of steel having a hardness of not less than 300 Brinell and having a ratio of length to thickness of not less than 60 and not more than 190, and a yield point sufiicient to permit a fiexure of not less than 2%" without permanent set in a length of in the order of two feet, said screen rod being generally rectilinear, and supports for said rod, on said deck, adapted to receive the opposite ends of said rod, said rod being insertable and removable by flexure into said supports.

9. In combination with a rod screen deck and means for vibrating it, a screen rod formed of steel having a hardness of not less than 300 Brinell and having a ratio of length to thickness of not less than 60 and not more than 190, and a yield point sufiicient to permit a flexure of not less than 2%" without permanent set in a length of in the order of two feet, said screen rod being generally rectilinear, and supports for said rod, on said deck, adapted to receive the opposite ends of said rod, said rod being insertable and removable by fiexure into said supports, and

means for maintaining such rod in fiexure on said deck.

10. In combination with a rod screen deck and means for vibrating it, a screen rod formed of steel having a hardness of not less than 300 Brinell and having a ratio of length to thickness of not less than 60 and not more than 190, and a yield point sufficient to permit a fiexure of not less than 2 /2" without permanent set in a length of in the order of two feet, said screen rod being generally rectilinear, and supports for said rod, on said deck, adapted to receive the opposite ends of said rod, said rod being insertable and removable by flexure into said supports, and means for maintaining such rod in fiexure on said deck, and upwardly flexed in relation to said deck.

11. A vibratory screen deck including side frame members, and transverse connecting members, and not less than three screen panels on said deck, each such screen panel including a plurality of longitudinally extending wires, said wires being arched to form a transversely extending convex surface for each said panel, said panels being located at. difierent angles in relation to the horizontal and being arranged to form a generally concave screening surface.

12. A vibratory screen deck including side frame members, and transverse connecting members, and not less than three screen panels on said deck, each such screen panel including a plurality of longitudinally extending wires, said wires being arched to form a transversely extending convex surface for eachsaid panel, said panels being located at different angles in rela-- tion to the horizontal and being arranged to form a generally concave screening surface, the panel nearest the feed end of the screen being the most highly inclined, the inclination of the panels from the horizontal being reduced progressively from the feed to the discharge end of the screen.

13. A vibratory screen deck including side frame members, and transverse connecting members, and not less than three screen panels on said deck, each such screen panel including a plurality of longitudinally extending wires, said wires being arched to form a transversely extending convex surface for each said panel, said panels being located at different angles in relation to the horizontal and being arranged to form a generally concave screening surface, and agitating baflies transversely extending across the decks between each adjacent pair of panels, said bafiies being of sufficient height to impart a substantial agitation to the material passing thereover, the convexity of the individual panels being suflicient to vary substantially the angular relation of the feed and discharge end of each panel to the horizontal.

14. A vibratory screen deck including side frame members, and transverse connecting members, and not less than three screen panels on said deck, each such screen panel including a plurality of longitudinally extending wires, said wires being arched to form a transversely extending convex surface for each said panel, said panels being located at different angles in relation to the horizontal and being arranged to form a generally concave screening surface, the panel nearest the feed end of the screen being the most highly inclined, the inclination of the panels from the horizontal being reduced progressively from the feed to the discharge end of the screen, and agitating baflles transversely extending across the decks between each adjacent pair of panels, said baffles being of sufficient height to impart a substantial agitation to the material passing thereover, the convexity of the individual panels being sufficient to vary substantially the angular relation of the feed and discharge end of each panel to the horizontal.

15. A vibratory screen deck, including not less than three screen panels on said deck, each such screen panel being arched to form a transversely extending convex surface for each panel, said panels being located at different angles in relation to the horizontal and being arranged to form a generally concave screening surface, the panel nearest the feed end of the screen being the most highly inclined, the inclination of the panels from the horizontal being reduced progressively from the feed to the discharge end of the screen, the convexity of the individual panels being sufficient to vary substantially the angular relation of the ieed and the discharge end of each panel to the horizontal.

16. A vibratory screen deck, including not less than three screen panels on said deck, each such screen panel being arched to form a transversely extending convex surface for each panel, I

said panels being located at different angles in relation to the horizontal and being arranged to form a generally concave screening surface, the panel nearest the feed end of the screen being the most highly inclined, the inclination of the panels from the horizontal being reduced progressively from the feed to the discharge end of 10 agitation to the material passing thereover.

LOREN G. BYMONS.

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