CA1059965A - Regrinding structure for hammermill - Google Patents
Regrinding structure for hammermillInfo
- Publication number
- CA1059965A CA1059965A CA234,941A CA234941A CA1059965A CA 1059965 A CA1059965 A CA 1059965A CA 234941 A CA234941 A CA 234941A CA 1059965 A CA1059965 A CA 1059965A
- Authority
- CA
- Canada
- Prior art keywords
- grinding
- grinding chamber
- chamber
- increments
- hammermill
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Crushing And Pulverization Processes (AREA)
Abstract
ABSTRACT
An improvement in the structure of the grinding chamber of a hammermill consisting of a transverse channel ex-tending across the lower portion of the grinding chamber of the hammermill, said channel serving as a barrier to momentarily halt and deflect upwardly increments of the material passing through said grinding chamber whereby said increments of mat-erial are engaged by the hammer blades to have such an effec-tive impact from said blades as to be again crushed or pulver-ized as on the order of the same extent as in connection with the first impact of said material by said blades upon said material first entering said grinding chamber. A very effec-tive crushing or pulverizing action takes place with the material being at a relative standstill when impacted by said hammer blades.
An improvement in the structure of the grinding chamber of a hammermill consisting of a transverse channel ex-tending across the lower portion of the grinding chamber of the hammermill, said channel serving as a barrier to momentarily halt and deflect upwardly increments of the material passing through said grinding chamber whereby said increments of mat-erial are engaged by the hammer blades to have such an effec-tive impact from said blades as to be again crushed or pulver-ized as on the order of the same extent as in connection with the first impact of said material by said blades upon said material first entering said grinding chamber. A very effec-tive crushing or pulverizing action takes place with the material being at a relative standstill when impacted by said hammer blades.
Description
SPE~CI FICATION
The invention herein relates to an improvement in the effective result of the grinding operation in the grinding chamber of a hammermill.
The hammers or cutting blades in a hammermill are carried by a rotor and are carried or driven at a speed of some 17 to 20 thousand fpm ~feet per minute) whereas free flowing material coming into the grinding chamber enters at the rate of some 60 fpm. Hence, the initial contact of the hammer blade with the material in view of their relative rates of speed represents an explosive impact of the blades with the material with a resulting very effective crushing action taking place at the instant of said impact. Once the material entering the grinding chamber has made one revolution, it accelerates very rapidly in approaching the speed of the hammer blades whereas the subsequent impact of the blades on the material 1059g~
is less effective than the first explosive impact. The pur-pose of the invention herein is to provide a structure whereby there may be subsequent impact between the hammer blades and the material being ground on the order of said first mentioned impact. The first impact of the hammer blade with the material being ground may be regarded as a first grinding effort. The invention herein provides at least one subsequent such grinding effort to increase substantially the grinding efficiency or effectiveness of the action within the grinding chamber.
It is an object of this invention therefore to provide means within the grinding chamber whereby there will be a subsequent impact between the hammer blades and the ma-terial being ground on the order of the first explosive impact between said blades and the material upon entering the grinding chamber.
It is another object of this invention to provide means within the grinding chamber of a hammermill whereby suc-cessive increments of the material being centrifuged therein are deflected and momentarily halted in at least one point of travel in moving through the grinding chamber and in being brought to a relative stop there result successive explosive impacts between the hammer blades and the relatively stationary quantities of material thus deflected, said impacts being on the order of the first impact of said blades with said material upon first coming into the grinding chamber whereby there re-sults an effective regrinding of said material.
More generally stated, it is an object of this in-vention to provide a transverse channel extending across the lower portion of the grinding chamber of a hammermill wherein successive quantities of the material moving centrifugally through said chamber engage and become deflected upwardly at said channel in sufficient quantity for crushing engagement by said hammer blades whereby there results what my be regarded
The invention herein relates to an improvement in the effective result of the grinding operation in the grinding chamber of a hammermill.
The hammers or cutting blades in a hammermill are carried by a rotor and are carried or driven at a speed of some 17 to 20 thousand fpm ~feet per minute) whereas free flowing material coming into the grinding chamber enters at the rate of some 60 fpm. Hence, the initial contact of the hammer blade with the material in view of their relative rates of speed represents an explosive impact of the blades with the material with a resulting very effective crushing action taking place at the instant of said impact. Once the material entering the grinding chamber has made one revolution, it accelerates very rapidly in approaching the speed of the hammer blades whereas the subsequent impact of the blades on the material 1059g~
is less effective than the first explosive impact. The pur-pose of the invention herein is to provide a structure whereby there may be subsequent impact between the hammer blades and the material being ground on the order of said first mentioned impact. The first impact of the hammer blade with the material being ground may be regarded as a first grinding effort. The invention herein provides at least one subsequent such grinding effort to increase substantially the grinding efficiency or effectiveness of the action within the grinding chamber.
It is an object of this invention therefore to provide means within the grinding chamber whereby there will be a subsequent impact between the hammer blades and the ma-terial being ground on the order of the first explosive impact between said blades and the material upon entering the grinding chamber.
It is another object of this invention to provide means within the grinding chamber of a hammermill whereby suc-cessive increments of the material being centrifuged therein are deflected and momentarily halted in at least one point of travel in moving through the grinding chamber and in being brought to a relative stop there result successive explosive impacts between the hammer blades and the relatively stationary quantities of material thus deflected, said impacts being on the order of the first impact of said blades with said material upon first coming into the grinding chamber whereby there re-sults an effective regrinding of said material.
More generally stated, it is an object of this in-vention to provide a transverse channel extending across the lower portion of the grinding chamber of a hammermill wherein successive quantities of the material moving centrifugally through said chamber engage and become deflected upwardly at said channel in sufficient quantity for crushing engagement by said hammer blades whereby there results what my be regarded
-2--" 1059965 as a regrinding effort.
It is a specific object of this invention to provide structure within the grinding chamber of a hammermill to have more than the initial explosive or crushing impact between the grinding member and the material therein with successive increments of said material being deflected and momentarily stopped well within the grinding chamber to pro-vide a subsequent grinding impact between said grinding member and said material.
These and other objects and advantages of the in-vention will be set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the several views and in which:
Fig. 1 is a view in side elevation of a hammermill structure;
Fig. 2 is a broken view in vertical section on an enlarged scale taken on line 2-2 of Fig. 1 as indicated;
Fig. 3 is a broken view in vertical section on an enlarged scale taken on line 3-3 of Fig. 2 as indicated;
Fig. 4 is a broken view of a detail of structure on an enlarged scale in vertical section taken on line 4-4 of Fig, 3;
Fig~ 5 is a broken view of a detail of structure in vertical section taken on line 5-5 of Fig. 4 as indicated; and Fig. 6 is a broken view of a detail of structure on an enlarged scale in horizontal section taken on line 6-6 of Fig. 4 as indicated.
Referring to the drawings, a hammermill structure is indicated by the reference numeral 10. Only so much of the structure of said hammermill will be disclosed and described as is believed necessary to support a full description of the structure comprising the subject matter of the invention herein.
` 1059965 Said housing 12 comprises a top wall 22, side walls23 and 24, a bottom wall 25 and an underlying supporting frame 27.
Within said housing 12 is a chamber 30. Disposed through said top wall 22 is an inlet chute 32 having diverging plate members 33 and 34 depending inwardly of said chamber 30.
Extending downwardly from said bottom wall 25 is a discharge outlet 36.
Said drive shaft 15 extends inwardly of said housing 12 and carries at its inner end a rotor 38 of a conventional type having mounted thereon hammer blades 40.
Adjacent the bottom of said chamber 30 carried on the back wall 42 thereof and extending forwardly thereof are a pair of spaced brackets 45 and 46. Said brackets respectively have a stub bearing shafts 47 and 48 to which are pivoted the lower end portions of screen retaining members 51 and 52.
Said screen retaining members are frame-like in form here shown to define a grinding chamber of tear-drop configuration and having their upper end postions 51a and 51b overlying the de-pending end portions of the plate members 33 and 34. Screenmembers 53 and 54 of appropriate mesh are respectively disposed within said frame members 51 and 52. The upper end portions of said frame members are engaged by locking or clamping members 60 and 61. Said clamping member 60 comprises a plate member 63 secured to the upper end portion of said retaining frame portion 51 and having a tubular rod 64 from which projects a screw rod 65 through the wall 23 being retained by an outer tubular boss or housing 66 through which said rod has at its outer end an operating handle 68. Rotation of said handle swings said retaining member 51 about said shaft 47 to draw the retain-ing member away from said plate member 33 to release the screen member retained therebetween or to secure the same in operating position, as the case may be. Said member 61 is of identical lOS9~65 structure as of said member 60. Said retaining members 51 and 52 and the screens 53 and 54 disposed therein for~ the side walls of a grinding chamber 70.
Shown carried by said depending plate member 34 is a deflection member 72 having its outer wall 73 angled to form a guide for incoming material to direct the same in the direction of rotation of said rotor 38. Said wall 73 has a small inward flange 74 formed at its lower end.
Extending transversely of the bottom of said grind-ing chamber 70 between said brackets 45 and 46 is a material deflection member 76 shown here in the form of a grooved or channel member which is here shown secured and supported at one end to the back wall 42 of said housing by a depending flange portion 77 as by bolts 78. Said channel member may take on various transverse configurations and is here shown being IJ-shaped in form.
Carried at the inner side of said door 18 spaced therefrom by posts 19 is a plate member 21 which overlies the screen retaining members 51 and 52 and forms the front wall of the grinding chamber 70.
The material entering the grinding chamber 70 and being ground therein is indicated by the reference character A.
The invention herein relates to increasing the effec-tiveness of the grinding operation of the grinding chamber of a hammermill and relates to increasing the capability and effectiveness of its grinding effort.
Material for grinding which is gravity fed into the grinding chamber of a hammermill enters the grinding chamber at a rate on the order of a speed of some 60 fpm. The rotor 38 has an average operating speed between 1700 and 2100 RPM
which represents a speed of the tips of the blades 40 on the order of something over 17000 fpm. It is the first impact at which the most crushing or pulverizing in the grinding operation 1~59~65 takes place for the material is at a relative standstill compared to the speed of the hammer blades. It is desirable to have a subsequent impact between the hammer blades and the material as severe or as crushing as said first impact.
The structure comprising the subject matter of the invention herein is designed to provide an additional opportunity for a grinding effort which is substantially equivalent to the crushing effect of the first step above described.
The member 76 as located represents the essential element of the invention in providing a channel across the lower portion of the grinding chamber. As a result of the cen-trifugal action provided by the hammer blades, the material to be ground is driven against the inner surface of the screen.
As increments of this material approach and engage the channel member 76, said increments are deflected upwardly by a wall of said channel and are thus momentarily halted relative to the speed of the hammer blades and at this point said increments of material thus halted are subjected to the explosive impact or crushing effect of the first hammer blades engaging them.
This is a continuous action with successive quantities of the material being deflected and brought to a relative halt so that with the passage of each hammer blade over this area, said material by impact of said hammer blades is crushed and pulver-ized and in being continuously subjected to this explosive im-pact, the result of this is that a very effective grinding or pulverizing of the material takes place. The successive quantities of material being deflected upwardly by the channel member 76 may be likened to a recurrence of the first or initial grinding effort or in effect being subjected to a regrinding effort.
The deflection member 72 as a result of its bottom wall 75 and flange portion 74 creates another area which serves to cause a deflection and a momentary halt of material which again is subjected to an explosive or crushing impact of the hammer blades. Hence 5 as a result of the function of the members 76 and 72, what in effect takes place within the grinding chamber adjacent these members might be regarded as a regrinding of material resulting in a very effective pulverization or re-duction of said material.
The channel member 76 alone or together with the member 72 as here shown substantially reduces the time other-wise required to sufficiently grind material to a desired reduction in size. This invention has materially increased the efficiency and the capability of the grinding operation of a hammermill and has substantially decreased the time required for grinding.
It will of course be understood that various changes may be made in form, details, arrangement and proportions of the parts without departing from the scope of the invention herein which, generally stated, consists in an apparatus capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.
It is a specific object of this invention to provide structure within the grinding chamber of a hammermill to have more than the initial explosive or crushing impact between the grinding member and the material therein with successive increments of said material being deflected and momentarily stopped well within the grinding chamber to pro-vide a subsequent grinding impact between said grinding member and said material.
These and other objects and advantages of the in-vention will be set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the several views and in which:
Fig. 1 is a view in side elevation of a hammermill structure;
Fig. 2 is a broken view in vertical section on an enlarged scale taken on line 2-2 of Fig. 1 as indicated;
Fig. 3 is a broken view in vertical section on an enlarged scale taken on line 3-3 of Fig. 2 as indicated;
Fig. 4 is a broken view of a detail of structure on an enlarged scale in vertical section taken on line 4-4 of Fig, 3;
Fig~ 5 is a broken view of a detail of structure in vertical section taken on line 5-5 of Fig. 4 as indicated; and Fig. 6 is a broken view of a detail of structure on an enlarged scale in horizontal section taken on line 6-6 of Fig. 4 as indicated.
Referring to the drawings, a hammermill structure is indicated by the reference numeral 10. Only so much of the structure of said hammermill will be disclosed and described as is believed necessary to support a full description of the structure comprising the subject matter of the invention herein.
` 1059965 Said housing 12 comprises a top wall 22, side walls23 and 24, a bottom wall 25 and an underlying supporting frame 27.
Within said housing 12 is a chamber 30. Disposed through said top wall 22 is an inlet chute 32 having diverging plate members 33 and 34 depending inwardly of said chamber 30.
Extending downwardly from said bottom wall 25 is a discharge outlet 36.
Said drive shaft 15 extends inwardly of said housing 12 and carries at its inner end a rotor 38 of a conventional type having mounted thereon hammer blades 40.
Adjacent the bottom of said chamber 30 carried on the back wall 42 thereof and extending forwardly thereof are a pair of spaced brackets 45 and 46. Said brackets respectively have a stub bearing shafts 47 and 48 to which are pivoted the lower end portions of screen retaining members 51 and 52.
Said screen retaining members are frame-like in form here shown to define a grinding chamber of tear-drop configuration and having their upper end postions 51a and 51b overlying the de-pending end portions of the plate members 33 and 34. Screenmembers 53 and 54 of appropriate mesh are respectively disposed within said frame members 51 and 52. The upper end portions of said frame members are engaged by locking or clamping members 60 and 61. Said clamping member 60 comprises a plate member 63 secured to the upper end portion of said retaining frame portion 51 and having a tubular rod 64 from which projects a screw rod 65 through the wall 23 being retained by an outer tubular boss or housing 66 through which said rod has at its outer end an operating handle 68. Rotation of said handle swings said retaining member 51 about said shaft 47 to draw the retain-ing member away from said plate member 33 to release the screen member retained therebetween or to secure the same in operating position, as the case may be. Said member 61 is of identical lOS9~65 structure as of said member 60. Said retaining members 51 and 52 and the screens 53 and 54 disposed therein for~ the side walls of a grinding chamber 70.
Shown carried by said depending plate member 34 is a deflection member 72 having its outer wall 73 angled to form a guide for incoming material to direct the same in the direction of rotation of said rotor 38. Said wall 73 has a small inward flange 74 formed at its lower end.
Extending transversely of the bottom of said grind-ing chamber 70 between said brackets 45 and 46 is a material deflection member 76 shown here in the form of a grooved or channel member which is here shown secured and supported at one end to the back wall 42 of said housing by a depending flange portion 77 as by bolts 78. Said channel member may take on various transverse configurations and is here shown being IJ-shaped in form.
Carried at the inner side of said door 18 spaced therefrom by posts 19 is a plate member 21 which overlies the screen retaining members 51 and 52 and forms the front wall of the grinding chamber 70.
The material entering the grinding chamber 70 and being ground therein is indicated by the reference character A.
The invention herein relates to increasing the effec-tiveness of the grinding operation of the grinding chamber of a hammermill and relates to increasing the capability and effectiveness of its grinding effort.
Material for grinding which is gravity fed into the grinding chamber of a hammermill enters the grinding chamber at a rate on the order of a speed of some 60 fpm. The rotor 38 has an average operating speed between 1700 and 2100 RPM
which represents a speed of the tips of the blades 40 on the order of something over 17000 fpm. It is the first impact at which the most crushing or pulverizing in the grinding operation 1~59~65 takes place for the material is at a relative standstill compared to the speed of the hammer blades. It is desirable to have a subsequent impact between the hammer blades and the material as severe or as crushing as said first impact.
The structure comprising the subject matter of the invention herein is designed to provide an additional opportunity for a grinding effort which is substantially equivalent to the crushing effect of the first step above described.
The member 76 as located represents the essential element of the invention in providing a channel across the lower portion of the grinding chamber. As a result of the cen-trifugal action provided by the hammer blades, the material to be ground is driven against the inner surface of the screen.
As increments of this material approach and engage the channel member 76, said increments are deflected upwardly by a wall of said channel and are thus momentarily halted relative to the speed of the hammer blades and at this point said increments of material thus halted are subjected to the explosive impact or crushing effect of the first hammer blades engaging them.
This is a continuous action with successive quantities of the material being deflected and brought to a relative halt so that with the passage of each hammer blade over this area, said material by impact of said hammer blades is crushed and pulver-ized and in being continuously subjected to this explosive im-pact, the result of this is that a very effective grinding or pulverizing of the material takes place. The successive quantities of material being deflected upwardly by the channel member 76 may be likened to a recurrence of the first or initial grinding effort or in effect being subjected to a regrinding effort.
The deflection member 72 as a result of its bottom wall 75 and flange portion 74 creates another area which serves to cause a deflection and a momentary halt of material which again is subjected to an explosive or crushing impact of the hammer blades. Hence 5 as a result of the function of the members 76 and 72, what in effect takes place within the grinding chamber adjacent these members might be regarded as a regrinding of material resulting in a very effective pulverization or re-duction of said material.
The channel member 76 alone or together with the member 72 as here shown substantially reduces the time other-wise required to sufficiently grind material to a desired reduction in size. This invention has materially increased the efficiency and the capability of the grinding operation of a hammermill and has substantially decreased the time required for grinding.
It will of course be understood that various changes may be made in form, details, arrangement and proportions of the parts without departing from the scope of the invention herein which, generally stated, consists in an apparatus capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.
Claims (4)
1. The grinding chamber of a hammermill, having in combination an inlet chute feeding material into said grinding chamber, a grinding member in said grinding chamber ro-tating at a speed substantially greater than the speed of travel of said material feeding thereinto, a channel forming member extending transversely of said grinding chamber, said channel member having a portion thereof deflecting upwardly increments of said material received therein passing through said grinding chamber and halting the forward movement thereof, and said grinding member impacting said upwardly deflected increments of material.
2. The structure set forth in claim 1, wherein said channel member is substantially U-shaped in cross section having a chamber therein to receive said material, and a side wall member deflecting upwardly said material.
3. The structure set forth in claim 1, wherein said channel member extending across the bottom of said grinding chamber in close proximity to the patch of said grinding member, and means removable securing said channel member.
4. The structure set forth in claim 1, including a deflecting means for a second deflection of material comprising a depending plate member carried by a side wall portion of said chamber, and a flange portion of said plate member stopping and deflecting increments of material passing through said chamber slowing down the passage of said material for impaction by said grinding member.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA234,941A CA1059965A (en) | 1975-09-08 | 1975-09-08 | Regrinding structure for hammermill |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA234,941A CA1059965A (en) | 1975-09-08 | 1975-09-08 | Regrinding structure for hammermill |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1059965A true CA1059965A (en) | 1979-08-07 |
Family
ID=4103985
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA234,941A Expired CA1059965A (en) | 1975-09-08 | 1975-09-08 | Regrinding structure for hammermill |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1059965A (en) |
-
1975
- 1975-09-08 CA CA234,941A patent/CA1059965A/en not_active Expired
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