US2009624A - Screen - Google Patents

Description

B. G. KLUGH July so, 1935.

SCREEN Filed Oct. 14, 1951 5 Sheets-Sheet 1 INVENTOR I ATTO RNEYS B. G. KLUGH SCREEN July 30, 1935.

0 6 0 2 2 L W T E Z W v F Mi w 2 I 7 fi i 9 i W i -EI 0/ A w 2 7 IR. 400/ 2 k kfi INVENTOR ,3. ifflugh B. G. KLUGH July 30, 1935.

5 Sheets-Sheet 5 R o T N E v m ATTORNEYS 5. G. KLUGH July 30, 1935.

SCREEN Filed 001;. 14, 1931 5 Sheets-Sheet 4 INVENTOR ATTORNEYS Patented July 30, 1935 UNITED STATES SCREEN Bethune G. Klugh, Birmingham, Ala., assignor to Swann Fertilizer Company, a corporation of Delaware Application October 14 12 Claims.

This invention relates to screening apparatus and has for its object the provision of such apparatus which shall be effective to separate a mass of particles of a multiplicity of sizes into separate 5 masses of particles of substantially uniform size, oversize particles, and particles smaller in size than the uniform sized particles sought.

A further object of my invention is to provide screening apparatus especially adapted to separate a mass of elongated particles of material of substantially uniform diameter into separate masses of particles of substantially uniform length, over-length particles, and particles shorter in length than the uniform length particles sought, together with fine material which may find its way into the mass.

A still further object of my invention is to provide screening apparatus effective to subject a mass of material to a plurality of screening operations and in which oversize material separated from the mass in any one of the screening operations is removed from the apparatus without being subjected to subsequent screening operations.

A still further object of my invention is to provide screening apparatus for separating uniform length particles from a mass of material of substantially uniform diameter and various lengths, and which shall embody a plurality of successive screening operations in which fines and shorter particles as well as overlength particles are progressively and separately screened out of the mass of substantially uniform length particles.

Another object of my invention is the provision 'of apparatus embodying a plurality of vibrating screens, and which shall include improved means whereby the amplitude of vibrations may be modified and varied and maintained within extremely narrow limits.

In my application, Serial No. 558,669, filed August 22, 1931, I have shown, described and claimed a process of producing concentrated fertilizer salts in which the salts are produced in the form of relatively dense, hard particles of sub- 45 stantially uniform diameter and of various lengths. The mass of particles is then subjected to screening and breaking operations to remove the fines and reduce the remaining particles to substantially uniform lengths. The apparatus 50 herein described and claimed is particularly adapted for screening the product described in my application aforesaid, though it will be apparent to those skilled in the art that it is equally useful for screening a wide variety of products.

In separating particles of substantially uni- 1931, Serial No. 568,757

form length from a mass of particles of substantially uniform diameter and various lengths, there is a problem involved which is not encountered in other screening operations. The particles must pass over the screen and in a single layer, maintaining their respective axes parallel to the screen surface. The openings in the screen must be of a size limited to pass the desired length particles only therethrough, so that overlength particles will pass over the entire screen surface. It then follows that the amplitude of vibrations must be limited to that necessary to propel the particles lying fiatwise on the screen surface, Without raising any particles to a distance from the said screen surface greater than that of the diameter of said particles.

In overcoming the problem set forth, I have devised a screening apparatus embodying a plurality of superposed overlappinginclincd screen units, each comprising in descending sequence a relatively fine foraminous section, and a coarser foraminous section. The coarser foraminous section overhangs the fine section of the next succeeding screen unit throughout the assembly, whereby particles passing through the coarser section of the upper screen unit are subjected to a plurality of screening operations. Particles passing through the finer section of each unit pass clear of the next succeeding unit to a hopper or bin common to all the finer sections. Oversize particles are carried from each screen unit over oversize aprons to a separate discharge for breaking treatment, and particles passing through the lowest coarser section are caught in a hopper or bin for the collection of the uniform sized product sought.

I have found that the elongated particles of material are moved in a single layer over the screen with particles lying parallel to the screen surface when such surface is at an angle slightly less than the angle of repose of the material, and 'when the amplitude of vibration of the surface is just sufiicient to project particles thereon from said surface a distance substantially equal to the diameter of the particles. I have found also that motion of the screen units is to be avoided in order to effect the selective separation sought. It is also necessary to repeat the screening of the product passing through the coarser section of the screen in order to remove all of the particles passing therethrough which exceed the predetermined length sought.

Apparatus embodying features of my invention is illustrated in the accompanying drawings, forming a part of this application, in which:

assembly through a hopper undersize materials are removed from the appa-' Fig. 1 is a side elevation of my improved screening apparatus;

Fig. 2 is a sectional view taken along the line 11-11 of Fig. 3;

Fig. 3 is a detail longitudinal sectional view of a portion of the apparatus showing the relationship of the screens to each other;

Fig. 4 is a longitudinal section through the tightening rod of one of the screen units;

Fig. 5 is a detail longitudinal sectional view illustrating the vibration imparting means employed;

Fig. 6 is a detail transverse sectional view illustrating the screen supporting means; and

Fig. 7 is a sectional view taken at right angles to Fig. 5.

Referring to the drawings for a better understanding of my invention, I show a screening apparatus comprising side frame members l0 supported in an inclined position by upright frame members I and transverse frame members l2. A plurality of screen units l3 are supported in a manner hereinafter to be described between the side frame members 'IO. Material to be treated is fed onto the upper end of the screen |4. Fines and ratus by a hopper or bin l6; and, material of the size sought is removed through a hopper or bin |1,- while oversize material passes directly from the apparatus to breaker rolls I3 for further treatment.

Each of the screen units l3 comprises a frame having longitudinal members I3 and transverse end members 2|. Joining the end members 2| are a plurality of rods 22 threaded on their ends 23 and 24 with right and left hand threads respectively which fit into ferrules 26 and 21 secured in the end members 2|. Secured to the upper side of the end members 2| are metal strips 23 and 23 to which the screen is secured.

The screen of each unit comprises a relatively v fine mesh foraminous section II which is joined to the upper metal strip 23 and extends downwardly to join a vibration strip 32 intermediate the end of the screen unit. Joined to the lower side of the vibration strip 32 is a relatively coarse foraminous screen section 33 which extends downwardly to join a relatively thin sheet metal strip 34 which determines the length of the coarse section. A vibration extension section 36 is Joined to the lower edge of the strip 34 and to the strip 23 secured to the lower end frame member 2|. The three sections of screen just described are joined to the metal strips by crimping, soldering, welding or other suitable joining means and the assembled unit is stretched tight on the screen unit frame by means of the threaded rods 22. v

The reasons for the peculiar construction Just described are that I have found that the total length of screen surface best subject to the control of vibration within the range required for the separation of predetermined length particles is between 24 and 30 inches. I havefurther found that the maximum length of screen over which such particles will fiow, under proper conditions of inclination and vibration, before the increased velocity of the longer sections causes them to collide one with the other and have the longer sections projected into vertical position, causing them to pass through the coarser screen, is between 12 and 14 inches. I have also noted in the develqrment'of this apparatus that the effective vibration of the screen stops along a line about /2 inch to 1 inch from the end.

In order therefore to provide for efficient screening under these determining factors, the

three sections of screen have been assembled into one unit as just described in order to obtain the full length of screen surface within which full and controlled vibration is produced. The finer section of the screen 3| is placed ahead of the coarser section 33 so as to cause the particles passing thereover to assume a fiat position on the screen surface when they reach the coarser section of the screen. The vibration extension screen 36 is finer than either of the sections preceding it and is not intended to pass any material therethrough. It is added for the purpose of maintaining positive vibration over the full length of travel of the product over the section 33 and also to prevent any piling up of oversize material andbuilding up of such material on the lower edge. of the section 33 which would result in projecting oversize material through the apertures of the sections 33.

The screen units are supported and disposed in the apparatus as shown in Figs. 2, 3, 6 and '7 of the drawings, wherein it will be noted that the side frame members IQ of each screen unit rest on angle brackets 3| secured to the side frame members l0, and end frame members 2| rest on angle 54 of the tappet guide frame of the. next succeeding screen unit.

As will be noted in Fig. 3 of the drawings, the screen units are arranged in superposed relation with the coarse section 33 of each unit overhanging the finer section 3| of the next succeeding screen unit, whereby material passing through the coarser sections 33 is subjected to repeated screening in order that oversize particles which may have passed through an upper section 33 of the previous unit are removed before passing through the final coarse section 33 into the bin Joined to the lower edge of each of the screen units beneath the overhanging metal strips 29 and spanning the next succeeding coarser section 33 is an oversize apron 4| so that the oversize material passing over each coarse section 33 is not subjected to further screening operation, but passes downwardly over'the oversize apron 4| to the end of the screen assembly. In order to prethe material flows by gravity downwardly over these oversize aprons.-

The means for imparting controlled vibrations to the screen units comprises a hammer and anvil mechanism which will now be described. Mounted in each of the vibration strips 32 are a plurality of anvil members 44. Each'of these anvil members is provided with a central cylindrical bore 43 and an upper fiange 41 and each is externally threaded on its lower end at 43. Each of the anvil members passes through a hole 49 provided in the vibration strip 32 and is maintained" in a true vertical position by means of beveled washers {ii and 52 fitting against the vibration strip 32 and held in place by means of the flange 41 and a nut 53 screwed onto the lower threaded end of the anvil member 48.

Joined to the side frame member |9 of each of the screen units is a tappet guide frame consisting of upper angle member 54 and lower angle member 57 extending transversely across the screen and secured to side frame member l9 by side angle member 60. The angle member 54 is directly above the anvil members 44 and is bored and internally threaded above each of the anvil members to accommodate a guide bushing 56 which is threaded to screw into the angle member 54. Angle member 57 is drilled and threaded beneath each of the anvil members 44 to accommodate a lower guide bushing 58.

Extending downwardly through the upper guide bushing 56, the anvil member 44, and the lower guide bushing 58, is a vertically disposed rod 59. The rod 59 is threaded at 6| to accommodate a hammer member 62 screwed onto it. The hammer member 62 is adjustably positioned on the rod 59 to impart the desired length of stroke and is held in place thereon by means of a lock member 63. It will be apparent that when the rod 59 is raised and released, the hammer member 62 will fall downwardly to strike the 'anvil members 44 and vibrate the screen. In order to prevent material coming in contact with and clogging the hammer members 62, I provide a sleeve 64 which surrounds the rod 59 and hammer members 62 and 63, and fitting into a hole 66 provided in the lower screen unit frame member 2|. This sleeve is formed with sufficient clearance to allow ready removal and free movement of the rodiand hammer members. The sleeve 64 has its lower terminus sufficiently high in hole 66 to permit extension of bushing 56 to register in the respective seats thereby formed and thus lock each succeeding screen unit in assembly.

Joining the lower angle member 51 and the next succeeding screen unit frame member 2| is an apron 61 for directing material downwardly onto the next succeeding fine section 3|, or in the case of the lowest screen unit, for directing the uniform sized product into the bin H. The lower edge of the vibration strip 32 is turned downwardly at 68 to form an apron for directing material passing through the upper end of the coarser section 33 onto the apron 61.

The rods 59 with their accompanying hammer members 62 are actuated by means of cams 1| mounted on shaft 12. All of the cam shafts 12 are driven through pulleys l3 and belt 14. The belt 14 is likewise passed over pulleys 16 mounted on the shafts 43 and thus drive the oversize brushes 42. The belt 14 is driven from any suitable source of power not shown.

From the foregoing description of my improved apparatus, its operation will be readily understood. A feeder roll I! mounted at the lower end of the hopper l4 serves to feed a controlled amount of material onto the upper screen unit I3 where it is first subjected to vibration from the vibrating strip 32 of that unit, causing it to move in a single layer downwardly over the screen surface. The major portion of the fine material passes directly through the section 3| into the bin l6 which spans the space determined by all the finer sections. The coarser material passes downwardly onto the coarser screen section 33 of the upper unit and the particles of the desired size together with some oversize particles pass through the upper coarse screen section 33 to fall upon the finer section 3| of the next succeeding screen unit. Oversize material passes over the top of the screen to the lower edge thereof, where it is removed by the brush 42 downwardly onto the oversize apron 4|, onto the next succeeding oversize apron 4|, and so on over all the oversize aprons to be subjected to a breaking operation in the rolls l8.

The successive screening of the particles passing through the coarser sections of the upper screen units serves finally to remove all of the oversize particles as well as the fines and a product of substantially uniform length is finally delivered into the hopper H.

The amplitude of vibration imparted to the screens may be modified and adjusted by adjusting the position of the hammer members 62 on the. rods 59,by increasing or decreasing the weight of hammer members 92, and by varying the speed and impact rate of cams 1|, so that all the particles will be propelled over the screen surface in single layer fiatwise positions.

In Fig. 5 of the drawings, I have indicated oversize particles of material 18, fines and undersize particles 19, and particles of the uniform length sought 8|. The vibration of the coarser screen section 33 should be such that no particles will be raised upwardly from the screen a distance greater than the diameter of the particles and all lie fiat on the screen, to prevent overlengths passing through the coarser screen section.

From the foregoing it will be apparent that I have devised an improved screening apparatus which is efiective to separate particles of substantially uniform length from a mass of particles of material of various lengths, together with separating out the fine materials from the size sought and the oversize, which apparatus is simple and sturdy of design and reliable in operation.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In a screen apparatus, an inclined supporting frame, a plurality of screen units mounted in the frame, each screen unit comprising in descending sequence a relatively fine foramlnous section, and a coarser foraminous section, the units being arranged in overlapping relation so that the coarser foraminous section overlies the next succeeding finer section, means for vibrating the screen units, oversize conveying means extending dowwardly from the lower end of each coarser section and spanning the next succeeding coarser section, power driven brushes for moving material from the lower end of each screen unit onto the next succeeding oversIze conveying means, and separate material receiving means for the material passing through the finer and coarser sections respectively of the screen units and for the oversize material.

2. In a screening apparatus, a screen unit comprising a frame adapted for disposal in'a downwardly inclined position at an angle less than the angle of repose of the material tobe screened, a

relatively fine foraminous section on the upper a relatively coarse foraminous section joining the lower edge of the vibrating strip, adjusting means for simultaneously tensioning both said foraminous sections and means to impart vibrations to the screen through the vibrating strip.

3. In a screening apparatus, a screen unit comprising a frame adapted for disposal in a down-v wardly inclined position at an angle less than the angle of repose of the-material to be screened, a relatively fine foraminous section on the upper side of the screen frame, a vibrating strip joining the lower edge of the relatively finesection, a relatively coarse foraminous section joining the lower edge of the vibrating strip, a metal strip joining the lower end of the coarser section, a vibration extension section joined to the lower edge of the metal strip and the screen frame, adjusting means for simultaneously tensioning both said foraminous sections and means to impart vibrations to the screen through the vibrating strip.

4. In a screening apparatus, a screen unit comprising a frame adapted for disposal in a downwardly inclined position at an angle less than the angle of repose of the material to be screened, a relatively fine foraminous section on the upper side of the 'screen frame, a vibrating strip joining the lower edge of the relatively fine section, a relatively coarse foraminous section joining the lower edge of the vibrating strip, a metal strip joining the lower end ofthe coarser section, a vibration extension section joined to the lower edge of the metal strip and the screen frame, means for simultaneously tensioning both said foraminous sections,-an anvil member secured to the vibrating strip, a hammer member adapted upon actuation to strike the anvil member, and a rotary cam for actuating the hammer member.

5. In a screening apparatus, a screen unit comprising a frame adapted for disposal in a downwardly inclined position at an angle less than the angle of repose of the material to be screened, a relatively fine foraminous section on the upper side of the screen frame, a vibrating strip joining the lower edge of the relatively fine section, a relatively coarse foraminous section joining the lower edge of the vibrating strip, a metal strip joining the lower end of the coarser section, a vibration extension section joined to the lower edge of the metal strip and the screen frame, means for simultaneously tensioning said foram-' inous sections without altering substantially the position of said vibrating strips, an anvil member secured to the vibrating'strip, a hammer member for coacting with the anvil member and comprising a vertically disposed rod adapted to be raised and fall on the anvil member when released, and a rotary cam for raising and re leasing the hammer member.

6. In a screening apparatus, a screen unit comprising a frame adapted for disposal in a downwardly inclined position at an angle less than the angle of repose of the material to be screened, a relatively fine foraminous section on the upper side of the screen frame, a vibrating strip joining the lower edge of the relatively fine section, -.a relatively coarse foraminous section joining the lower edge of the vibrating strip, a metal strip joiningthe lower end of the coarser section, a vibration extension section joined to the lower edge of the metal strip and the screen frame, means for simultaneously tensioning said foraminous sections, a plurality of anvil members secured to the vibrating strip, a hammer member for coacting with each of the anvil members and comprising a vertically disposed rod adapted to be raised and fall on the anvil member when re leased, and synchronously driven rotary cam members for raising and releasing the hammer members.

7. In a screening apparatus, a screen unit comprising "a frame adapted for disposal in a downwardly inclined position at an angle less than the angle of repose of the material to be screened, a relatively fine foraminous section on the upper side of the screen frame, a vibrating strip joining the lower edge of the relatively fine section, a relatively coarse foraminous section joining the lower edge of the vibrating strip, a metal strip joining the lower end of the coarser section, a vibration extension section of foraminous material joined to the lower edge of the metal strip and the screen frame, means for simultaneously tensioning said foraminous sections, a plurality of anvil members secured to the vibrating strip, a hammer member for coacting with each of the anvil members and comprising a vertically disposed rod adapted to be raised and fall on the anvil member when released, means for adjusting the length of stroke of the hammer member, and synchronously driven rotary cam members for raising and releasing the hammer members.

8. In a screening apparatus, a plurality of overlapping inclined screen units each comprising in descending sequence a relatively fine foraminous section, a vibrating strip, a relatively coarse foraminous section, a metallic strip and a vibration extension section of foraminous material, the relatively coarse section of each unit overlapping the relatively fine section of the next succeeding unit, and synchronously driven means for imparting vibrations to the screen units through the vibrating strips.

9. In a screening apparatus, a plurality of overlapping inclined screen units each comprising in descending sequence a relatively fine adjustably tensioned foraminous section, a vibrating strip, a relatively coarse adjustably tensioned foraminous section, a metallic strip and a vibration extension section, the relatively coarse section of each unit 45 overlapping the relatively fine section of the next succeeding unit, a plurality of anvil members carried by each vibrating strip, a plurality of adjustable hammer members cooperating with the anvil members for imparting vibrations thereto, and synchronously driven rotary cam members for actuating the hammer members.

10. In a screening apparatus, a plurality of overlapping inclined screen units each comprising in descending sequence a relatively fine foraminous section, a vibrating strip, a relatively coarse foraminous section, a metallic strip and a vibration extension section, the relatively coarse section of each unit overlapping the relatively fine section of the next succeeding unit, a screen frame provided with screen tensioning means for each unit, a plurality of anvil members carried by each vibrating strip, a plurality of adjustable hammer members cooperating with the anvil members for imparting vibrations thereto, a guide frame for said hammer members and rigidly attached to the screen frame units, and synchronously driven rotary cam members for actuating the hammer members.

tion of each unit overlapping the relatively fine section of the next succeeding unit, a screen frame for each unit, means for tensioning said foraminous sections simultaneously, a plurality of anvil members carried by each vibrating strip, a plurality of adjustable hammer members cooperating with the anvil members for imparting vibrations thereto, a guide frame for said hammer members rigidly disposed transversely over said screen unit and adapted to coact in locking position with the lower frame member of the preceding screen unit in the assembly, and synchronously driven cam members for actuating the hammer members.

12. In a screening apparatus, a plurality of overlapping inclined screen units each comprising in descending sequence a relatively fine foraminous section, a vibrating strip, a relatively coarse foraminous section, a metallic strip and a vibration extension section, the relatively coarse section of each unit overlapping the relatively fine section of the next succeeding unit, means for tensioning said foraminous sections simul taneously without substantially altering the position of said vibrating strip, a screen frame for each unit, a plurality of adjustable vertically disposed and removable rod-like hammer members cooperating gath the anvil members for imparting vibrations thereto, a guide frame for the hammer members extending transversely of the screen frame, a protecting tube for each hammer member disposed in the screen frame and covering the upper end of each of the hammer members, and means for actuating the hammer members.

BETHUNE G. KLUGH.

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