US3352501A

US3352501A - Grinding apparatus

Info

Publication number: US3352501A
Application number: US444361A
Authority: US
Inventors: Sr Alfred F Krumholz
Original assignee: Chicago Boiler Co
Current assignee: Chicago Boiler Co
Priority date: 1965-03-31
Filing date: 1965-03-31
Publication date: 1967-11-14
Anticipated expiration: 1984-11-14

Description

NOV. 14, 1967 KRUMHQLZ 5 3,352,501

GRINDING APPARATUS Filed March 31, 1965 2 Sheets-Sheet l FgLg i U L 4' 7| I 70 I Inventor V I JHfr ed Flirumholgsr.

' .flfiornegfi United States Patent 3,352,501 GRINDING APPARATUS Alfred F. Krumholz, Sr., Glenview, Ill., assignor to Chicago Boiler Company, Chicago, 111., a corporation of Illinois Filed Mar. 31, 1965, Ser. No. 444,361 8 Claims. (Cl. 241-74) ABSTRACT OF THE DISCLOSURE A sand or like grinder having impellers, for grinding pigments and the like, is so constructed as to enable the impeller shaft to be easily removed for cleaning.

This invention relates to apparatus for dispersing particulate solids in a liquid media and/ or reducing the size of the particles.

The present invention is particularly adapted for use with the so-called sand grinding process ommonly employed to disperse and deagglomerate pigment in a liquid as described in US. Patent No. 2,855,156. This process has been employed with favorable results while using sand or other grinding media, for example steel balls, glass beads, etc. have also been employed for dispersing and deagglomerating materials. Likewise, the process is used to deagglomerate and disperse a wide variety of materials or particulate solids other than pigments.

Heretofore, known commercial sand grinding apparatus, such as illustrated in US. Patent Nos. 2,855,156 and 3,050,263, have employed a rotatable shaft driven from the top of a mixing vessel in which is disposed the particular solids, grinding medium and liquid. This rotatable shaft carries a series of impellers which agitate the mixture to disperse and deagglomerate the particulate solids. Either at the top or the bottom of the vessel a screen is employed to separate the grinding media from the mixture of particular solids and liquids being discharged through an outlet from the vessel.

In some instances the rotatable shaft is directly connected to a motor supported at the top of the vessel and in other instances the shaft is driven by a drive belt or chain at the top of the vessel leading to a motor. In any event, some difliculties, although admittedly not insurmountable, have been experienced in either type of arrangement when it is desired to clean or service the vessel such as when changing the color or pigment, type of grinding media or screen employed therein, and the primary object .of the present invention is to so construct grinding apparatus as to facilitate cleaning and servicing. More specifically, an object of the invention is a mixing vessel having the top thereof unencumbered by a drive mechanism and having a rotatable impeller shaft extending through the bottom of the vessel for connection to a drive mechanism.

A common occurrence with grinding apparatus of the type exemplified by the above-identified prior art is that the screen for separating the grinding media from the discharged material becomes clogged or covered with dried or solidified material which reduces the flow rate of discharge. Also when changing materials or pigments it is many times required that the screen be replaced by a screen of different size or by a screen free of such dried material. Accordingly, another object of the present invention is to construct a sand grinding machine with a removable upper cover unhampered by a motor for the rotatable shaft to permit ready access to the separating screen.

A further problem with grinding apparatus, as exemplified by the above cited patents, is that deposits of grinding media tend to accumulate on the tops of the disks or impellers. Flushing with a cleaning solvent or rotation of the impeller shaft without fluid medium in the vessel has not proved satisfactory in removing such deposits. Rotation of the shaft without a fluid in the vessel is an undesirable practice because the unsecured lower end of the shaft wobbles and can result in damage to the shaft and to the bearings for the shaft. Accordingly, a further object of the present invention is a sand grinding apparatus in which the impeller shaft can be readily removed outwardly from the top of the vessel without dismantling of the drive for the shaft so that the impellers and the interior of the vessel can be readily serviced or cleaned.

Because of the particular abrasive nature of the sand pigments and particular solids and the penetrating ability of solvents and other liquids used Within the grinder, it has heretofore been a particularly diflicult problem to afford a tight shaft seal at the top of the vessel, no less at the bottom of the vessel. Accordingly, a further object of the invention is a new and improved shaft seal and drive apparatus for the rotatable shaft of the grinding apparatus capable of withstanding such severe operating conditions.

Another object of this invention is to construct sand grinding apparatus having an upper bearing protected by a shaft seal and a lower drive shaft extending upwardly through the bottom of the vesel for connection to the rotatable impeller shaft, the drive shaft being protected by a seal; and a further object is to facilitate service and repair of such apparatus by having the shaft seal for the drive shaft removable with the impeller shaft.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration show preferred embodiments of the present invention and the principles thereof and what is now considered to be the best mode contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention.

In the drawings:

FIG. 1 is a sectional view showing a grinding apparatus incorporating the preferred embodiment of the invention;

FIG. 2 is an enlarged sectional view of the upper end of the impeller shaft and shaft seal;

FIG. 3 is an enlarged sectional view of the drive shaft and its connection to the impeller shaft and of the shaft seal for the drive shaft;

FIG. 4 is a view taken along the line 44 of FIG. 1 in the direction of the arrows showing the mounting of the drive motor;

FIG. 5 is a sectional view taken along the line 55 of FIG. 4 showing the pivotal mounting of the motor for controlling tension in a drive belt; and

FIG. 6 is a sectional view taken along the line 66 of FIG. 4 showing the mounting of the drive motor.

Referring now to the drawings and more particularly to FIG. 1 there is illustrated a sand grinding apparatus incorporating the preferred-embodiment of the invention. The sand grinding apparatus has a generally fiat base 10, an upstanding plate 11 on the base 10 for holding a cylindrical vessel 12 in which is dispersed and deagglomerated particulate solids or the like. The vessel 12 is usually vertically oriented in a generally vertical direction with an impeller shaft 14 disposed on the vertical axis at the center of the cylindrical vessel 12. The rotatable shaft 14 has a series of impellers 15 secured thereto for agitating and mixing the sand and slurry within the vessel 12.

In the grinding apparatus herein described, a slurry mixture consisting of a particulate solid such as a pigment and a fluid or film-forming vehicle would enter through an inlet pipe 18 disposed at the bottom of the vessel 12. The grinding media such as sand would already be within the vessel for mixing with the incoming slurry. The lower interior portion of the vessel 12 is defined by an inner cylindrical wall portion 20, which is surrounded by an annular cooling jacket formed between the wall 20 and the lower portion of an outer cylindrical wall 21 of the vessel 12. Cooling water enters between the

walls

20 and 21 through an inlet pipe 22 and is circulated to cool the surface of the cylindrical wall 20 and exits at the top through an outlet pipe 24.

As the sand and slurry mixture is agitated by the impellers 15, the sand and slurry is forced upwardly into an annular chamber 25 formed within a cylindrical screen member 26 which serves to separate the grinding media from the slurry. The now mixed and dispersed slurry mixture is forced through the screen member 26 into an annular space 30 about the screen member 26 for exiting through an outlet pipe 32 at the top of the vessel 12. The screen member 26 has secured about its upper and lower peripheral edges a pair of spaced

sealing rings

27 and 28. The sealing ring 27 is in tight sealing engagement with a flange 29 on the cylindrical wall 20 to prevent the leakage of the grinding media or slurry between the flange 29 and screen member 26. Likewise, the top cover plate 35 tightly engages the upper sealing ring 28 to prevent leakage of grinding media or slurry from the top edge of the screen member 26.

It will be appreciated that the screening member 26 can be completely cylindrical or semi-cylindrical or of various sizes and shapes. Also, the size of the screen openings can be selected either for the particular type of grinding media involved, such as 'sand or balls of larger diameter than the grains of sand; or the screen can be selected for the type and viscosity of the slurry mixture. After considerable usage, the screen often becomes clogged with particles. Typically, such clogging is caused 'by the accumulation of particles which have not been ground sufficiently to pass through the screen or by the drying of liquids on the screen. Thus, when changing the type of grinding media or changing the type of materials being ground, such as different colors of pigment, it is often necessary or most desirable to afford ready access to the interior of the vessel 12. For instance, the screen member 26 may need to be cleaned of colored pigments or replaced by a screen member having a different size of screen openings.

An important aspect of the present invention is the facilitating of access to the screen and to the interior of the vessel 12. A problem with prior art apparatus of the general type hereinbefore described is that the drive for the impeller shaft such as the shaft 14 was from the top of the vehicle and required a complete dismantling or at least a partial dismantling of the drive; and often required removal of a portion of the drive from above the impeller shaft 14 before the top cover could be lifted to afford the needed access to the interior of the vessel. However, under the present invention a top cover35 may be easily and quickly detached by loosening fasteners 36 and lifting the cover plate 35 directly from the top of the shaft 14. As best seen in FIG. 2,

the upper end of the shaft 14 is reduced in diameter at 38, this smaller diameter portion 38 being disposed for rotation within a bearing 39 carried in a seal housing 40 welded or otherwise secured to the top plate 35. The bearing 39 rests on an annular shoulder 41 formed in the bore 42 of the seal housing 40. An end cap 44 is threaded into the top portion of the seal housing 40. The end cap 44 seals the bore 42 against the exhausting 42 in the housing 40.

The seal housing 40 has an inner cavity or chamber 45 of upwardly tapering configuration towards the bearing 39. The decreasing diameter of the annular chamber 45 enhances the compressing and trapping of air within the chamber of space 45 upon the initial entry of sand and slurry mixture into the lower portion of, the air chamber 45. This compressed air serves as a sealing means for preventing the movement of the sand and bearing 39 may "be a solid bearing of plastic, bronze,

babbitt; or may be a ball or roller bearing.

Inspection, servicing or repair of the interior of the sand grinder is facilitated by removal of the top plate 35 and bearing 39 from the end of the shaft 14. Thus, the interior of the sand grinder is exposed for servicing or the like. When using sand and certain other types of grinding media, stopping of the rotation of the shaft 14 tends to deposit grinding media on the tops of the impellers 15. This deposited grinding media is diflicult to remove from the impellers 15 without removal of the shaft 14 and its attached impellers 15. Thus, in many instances, it is desired to lift the impeller shaft 14 and to remove the shaft 14 and its impellers 15 for cleaning.

The removal of the impeller shaft 14 is facilitated under the present invention not only by elimination of an upper drive for the impeller shaft, as hereinbefore described, but also by the manner of ready disconnection of the impeller shaft 14 from a drive shaft 50 extending upwardly through a bottom plate 51 at the bottom of the vessel 12.

As best seen in FIG. 3, the lower end of the, shaft 14 has a coupling 52 secured thereto as by welding. The coupling 52 has a generally square socket or internal cavity 53 formed by intersecting flat side walls. A complementary or mating square end 55 of the shaft 50 extends or telescopes into the coupling cavity 53. Thus, rotation of the drive shaft 50 causes rotation of the shaft of the impellers 14 through the coupling 52 wherein the square drive shaft 55 is fitted into the complementary square shaped cavity 53.

g The drive shaft 50 'is journaled for rotation in the upper bearing 57.and in a pair of

lower bearings

58 and 59 held in a bracket 60. The upper bearing 57 is preferably a flange type of bearing having an upper flange 62 serving as a thrust bearing for the coupling 52 and thereby a thrust bearing for the impeller shaft 14. The flange 62 of the bearing 57 rests on the upper annular surface 64 of a cylindrical bearing housing 66 preferably secured as by welding to the lower plate 51. The bearing 57 is fitted Within the circular opening 67 of the bearing housing 66. Also a packing 68 may be disposed against the bottom surface of the bearing 57 and about the drive shaft 50.

The packing 68 or mechanical seal is compressed between the bottom of the upper bearing '57 and the top shoulder of an annular gland 70 which is secured by cap screws 71 to the bottom plate 51. The packing 68 or mechanical seal serves to prevent the loss of air from a sealing means, described hereinafter. This sealing means the side wall 74 of the bell shaped member 75 of the coupling 52. Preferably, both the

side walls

72 and 74 are tapered to assist in the compressing of air by afford- 1ng a smaller and smaller annular cavity for the air as the slurry mixture'moves upwardly into the air chamber to further compress the air therein. That is, upon the initial charge of slurry, the slurry will move upwardly between the

side walls

72 and 74 until stopped by the trapped air, now compressed, at the top portion of the annular air space which thereafter serves as a seal to prevent contamination of the bearing 57 by either the sand or slurry mixture. The compressed air seal also prevents the escape of the slurry out of the sand grinder along the shaft 50. The packing 68 or mechanical seal serves to hold the compressed air from exiting along the shaft 50 of the sand grinder. If it is warranted, a compressed air conduit can be afforded in the bearing housing 66 leading to the annular air chamber formed by

side walls

72 and 74 to assist in maintaining the compressed air serving as the sealing means. Also it is to be understood that either one or both of the surfaces 72 may be tapered or not tapered, as preferred, so long as the compressed air chamber is formed therebetween to protect the bearing 62.

Collars

84 and 85 are secured to the drive shaft 50 and spaced to accommodate the

bearings

58 and 59 against which the

collars

84 and 85 engage, respectively, with vertical movements of the drive shaft 50. Thus, the

bearings

58 and 59 function as thrust bearings for the drive shaft 56. The

bearings

58 and 59 are held by the bracket 60 having a generally vertical extending arm 90 secured by fasteners 91 to-the bottom of the vessel 12.

The manner of mounting the vessel 12 and the motor M on the upstanding supporting plate 11 is more readily apparent from a consideration of FIGS. 1, 4, 5 and 6. As best seen in FIGS. 1 and 5, the outer wall 21 of the vessel 12 is secured to a vertically oriented plate 95 by a pair of vertically extending

gussets

96 and 97 each of which is welded along one edge to the cylindrical wall 21 and along the other edge to the support plate 95. Bolt and nut fasteners 98 are inserted through aligned apertures in the

plates

95 and 11 and are tightened to detachably mount the vessel 12 to the upstanding plate 11 on the base 10.

The upstanding plate 11 is bent at right angles at the vertical edges thereof to form a pair of rearwardly extending gussets 100, FIG. 1, of generally triangular shape which extend rearwardly from the vessel 12 and plate 11. The gussets 100 are welded along bottom edges thereof to the top plate of the base 10. Thus, the gussets 100 and the upstanding plate 11 constitute a generally U-shaped support, FIG. 5, within which is disposed the mounting bracket 105 for the motor 83.

The motor 83 is secured by bolts 106, FIG. 4, to a mounting member 108 having an inwardly turned, upper flange 109 and an inwardly turned, downward flange 110. The upper flange 109 is adapted to rest on a horizontal leg of an angle brace 112 welded or otherwise secured to the rear of the upstanding plate 11. The inward turned flange 110 is disposed for cooperation with a horizontal leg of an angle 113 welded or otherwise secured to the rear surface of the upstanding plate 11.

For control of tension of the drive belts 80 on the

sheaves

78 and 81, it is preferred that the motor 83 be pivotally mounted by its bracket means 105. Hence, the motor shaft 82 can be moved to the drive shaft 50 to loosen the drive belts 80 so that the belts 80 can be removed. Conversely, the drive shaft 50 can be moved to tighten the drive belts to their proper tension. For this purpose the support member 108 is pivotally mounted by

studs

115 and 116 to the

respective angle brackets

112 and 113 and slots such as 118, FIG. 5, are formed to receive locking

bolts

119 and 120 to lock the bracket 105 against pivotal movement about the

studs

115 and 116 while preventing pivotal movement of the motor 83 thereabout.

To afford a relatively fine adjustment when tensioning the drive belt 80, the support member 108 has a nut 123 welded thereto through which is threaded a bolt 124.

6 Thus, turning of the bolt 124 in the nut 123 in one direction will permit the swinging of the motor 83 toward the upstanding plate 11 to loosen the drive belts 80, and turning of the bolt 124 in the opposite direction will exert a force on the belts to tension or tighten the belts 80 to the requisite degree required.

From the foregoing, it will be seen that the present invention affords a novel grinding apparatus having a bottom drive facilitating the removal and cleaning of the interior of the grinding apparatus without disconnecting or dismantling the screen member such as 26 could be employed at the bottom of the vessel and still be retained ,accessable for removal and inspection without necessitating disconnecting the drive at the top of the lever as was heretofore the practice.

Hence, while preferred embodiments of the invention have been described and illustrated, it is to be understood that they are capable of variation and modification.

I claim:

1. Apparatus for the deagglomerating and dispersing of particulate solids in a liquid by a means of a grinding medium comprising: an upright vessel for a mixture of the grinding medium liquid and solids therein, a top plate means at the top of said vessel and detachable therefrom, a bottom plate means on said vessel, an impeller shaft means extending vertically downward from said top plate means and journaled for rotation in said top plate means, a screen means in said vessel adjacent an outlet from said vessel for screening the grinding medium from the mixture of particulate solids and the liquid, a drive shaft means extending upwardly from the bottom plate means and adapted to be rotated, coupling means for coupling said drive shaft means to said impeller shaft means for rotating said impeller shaft means with said drive shaft means, sealing means for sealing said drive shaft means for preventing the flow of particular solids, grinding medium or liquid, downwardly along said drive shaft means and from said vessel, and drive means for driving said shaft.

2. Apparatus of claim 1 wherein said coupling means has a socket for receiving a portion of said driving shaft means, said impeller shaft means and said drive shaft means adapted for disconnection upon removing said socket from said portion of said drive shaft means.

3. Apparatus of claim 1 wherein said sealing means includes an air chamber for trapping air under pressure to prevent movement of said particulate solids past said air chamber and along said drive shaft means.

4. Apparatus of claim 1 wherein said drive means includes a driving motor spaced from said drive shaft means, and belt means extending between said driving motor and said drive shaft means for rotating said drive shaft means.

5. Apparatus for deagglomerating and dispersing particulate solids in liquids by a grinding medium comprising: a generally cylindrical vessel having an inlet for introduc ing a mixture of particulate solids and liquids under pressure and having an outlet for discharge of dispersed and ground particles in said liquid, a screen means in said vessel for separating said grinding medium from said dispersion intended for said outlet, a separate top access plate on said vessel, an air bell secured to said top plate, a rotatable impeller shaft means extending into said air bell and downwardly into said vessel for agitating said mixture and grinding medium, a top bearing for said impeller shaft means disposed outwardly of said air bell which serves as a shaft seal to prevent the entrance of said solids, liquids or grinding medium into said top bearing, a bottom plate on said vessel having an opening therein, a drive shaft extending upwardly through said opening in said bottom plate, coupling means coupling said drive shaft to said impeller shaft means, means for sealing said drive shaft at said opening in said bottom plate, and drive means for driving said drive shaft.

6. Apparatus of claim 5 including a bearing support secured to said bottom plate, a bearing supported on said bearing plate and having a portion thereof serving as a thrust bearing surface 'for the rotatableimpeller shaft means, said sealing means sealing said bearing against contamination by said grinding medium, particulate solids or liquids.

7. Apparatus of claim 5 including a bracket means, a bearing means for said drive shaft secured in said bracket means for journaling therein said drive shaft.

8. Apparatus of claim 5 including a support means, said driving means including a motor mounted on said support means for pivotal movement on said support means, means to lock said motor means in a pivotal position, and driving belt means extending between said motor means and said drive shaft for driving said drive shaft and said impeller shaft means to deaggl'o'rnerate and disperse said particulate solids in said liquid.

References Cited UNITED STATES PATENTS Hoxt.

Fuller 24174 Ahlr'nann 241-172 X Tr'ede a 30836.3 Schwaneke 259108 Rohling'er E 241-74 De Gail 24174 Norris 241179 Goeser 24174 X Tight 241- 172 X FOREIGN PATENTS ANDREW R. JUHASZ, Primary Examiner.

HARRY F.7PEPPER, JR., Examiner.

Claims

1. APPARATUS FOR THE DEAGGLOMERATING AND DISPERSING OF PARTICULATE SOLIDS IN A LIQUID BY A MEANS OF A GRINDING MEDIUM COMPRISING: AN UPRIGHT VESSEL FOR A MIXTURE OF THE GRINDING MEDIUM LIQUID AND SOLIDS THEREIN, A TOP PLATE MEANS AT THE TOP OF SAID VESSEL AND DETACHABLE THEREFROM, A BOTTOM PLATE MEANS ON SAID VESSEL, AN IMPELLER SHAFT MEANS EXTENDING VERTICALLY DOWNWARD FROM SAID TOP PLATE MEANS AND JOURNALED FOR ROTATION IN SAID TOP PLATE MEANS, A SCREEN MEANS IN SAID VESSEL ADJACENT AN OUTLET FROM SAID VESSEL FOR SCREENING THE GRINDING MEDIUM FROM THE MIXTURE OF PARTICULATE SOLIDS AND THE LIQUID, A DRIVE SHAFT MEANS EXTENDING UPWARDLY FROM THE BOTTOM PLATE MEANS AND ADAPTED TO BE ROTATED, COUPLING MEANS FOR COUPLING SAID DRIVE SHAFT MEANS TO SAID IMPELLER SHAFT MEANS FOR ROTATING SAID IMPELLER SHAFT MEANS WITH SAID DRIVE SHAFT MEANS, SEALING MEANS FOR SEALING SAID DRIVE SHAFT MEANS FOR PREVENTING THE FLOW OF PARTICULAR SOLIDS, GRINDING MEDIUM OR LIQUID, DOWNWARDLY ALONG SAID DRIVE SHAFT MEANS, AND FROM SAID VESSEL, AND DRIVE MEANS FOR DRIVING SAID SHAFT.