EP0641601A2 - Broyeur agricole à marteaux et procédé de broyage fin de céréales - Google Patents

Broyeur agricole à marteaux et procédé de broyage fin de céréales Download PDF

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Publication number
EP0641601A2
EP0641601A2 EP94306501A EP94306501A EP0641601A2 EP 0641601 A2 EP0641601 A2 EP 0641601A2 EP 94306501 A EP94306501 A EP 94306501A EP 94306501 A EP94306501 A EP 94306501A EP 0641601 A2 EP0641601 A2 EP 0641601A2
Authority
EP
European Patent Office
Prior art keywords
hammer
rotor
hammers
inlet
screenwall
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.)
Withdrawn
Application number
EP94306501A
Other languages
German (de)
English (en)
Other versions
EP0641601A3 (fr
Inventor
James O. Hudson
Heath Hartwig
Kelsey C. Thom Jr.
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Roskamp Champion
Original Assignee
Roskamp Champion
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Roskamp Champion filed Critical Roskamp Champion
Publication of EP0641601A2 publication Critical patent/EP0641601A2/fr
Publication of EP0641601A3 publication Critical patent/EP0641601A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
    • B02C13/26—Details
    • B02C13/28—Shape or construction of beater elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
    • B02C13/02—Disintegrating by mills having rotary beater elements ; Hammer mills with horizontal rotor shaft
    • B02C13/04—Disintegrating by mills having rotary beater elements ; Hammer mills with horizontal rotor shaft with beaters hinged to the rotor; Hammer mills

Definitions

  • This invention relates generally to grain processing machinery and more particularly to agricultural hammermills for impact grinding of grains.
  • cereal grains and feed grains are commonly dried, ground, mixed, conditioned and pelletised or flaked.
  • conditioning and pelleting may require that the grain be ground to different degrees of coarseness.
  • Agricultural hammermills usually operate with constant speed motors at either 1800 rpm or 3600 rpm.
  • the higher speed mills are usually restricted to smaller sizes; because the high centrifugal loads at high speed require either heavier rotor and frame structures which increases the cost of the mill or a decrease in rotor diameter which causes a decrease in mill capacity.
  • Heavy duty hammermills used in other industries such as mineral dressing and metals processing and recycling may provide higher capacity but at prohibitive cost.
  • particle size of the ground grain is inversely proportional to tip speed of the hammers, so that particles of 800 micron or larger size are produced at about 12,500 feet per minute (3810m/min), 700 to 800 microns at about 17,500 feet per minute (5334m/min), 550 to 700 microns at about 20,000 feet per minute (6096m/min), and less than 500 microns at about 25,000 feet per minute (7620m/min). Therefore, achievement of a fine grind of 500 microns or less requires a high speed hammermill with all the strength and cost penalties already described. These penalties have effectively limited hammermill grinding of grains such that achievement of particle sizes smaller than the 550 to 700 micron range at practical production rates has been very costly if not impossible.
  • an agricultural hammermill for fine grinding of feed grains, comprising: a housing having a grain inlet in an upper portion, a ground particle discharge in a lower portion, and a grinding chamber between said inlet and said discharge; an apertured screenwall, surrounding said grinding chamber, having an open top adjacent said inlet for receiving grain, having apertures of at least 2000 microns, being formed as a portion of a horizontal cylinder above said discharge, and having straight tangential portions converging to said inlet; a rotor on a rotatably driven shaft mounted coaxially within said horizontal cylinder portion of said apertured screenwall, said rotor comprising a plurality of discs mounted on said shaft, each said disc having at least two hammer support pivot pins symmetrically disposed near the periphery of said disc; means for rotating said shaft and rotor at a substantially constant speed of 1800 rpm; and a plurality of hammers, one said hammer being pivotally supported on each said pin
  • a method of fine grinding grain using an agricultural hammermill for fine grinding of feed grains having an apertured screenwall surrounding a grinding chamber, said screenwall having apertures of at least 2000 microns and being formed as a portion of a horizontal cylinder above a discharge, there being a rotor mounted coaxially within said horizontal cylinder portion of said screenwall, said rotor comprising a plurality of discs mounted on said shaft, each said disc having at least two hammer support pivot pins symmetrically disposed near the periphery of said disc and a plurality of hammers, one said hammer being pivotally supported on each said pin, said hammers each have a specified length; and the method including rotating said rotor at a substantially constant speed of 1800 rpm, characterised in that the outboard tip of said hammer swings at substantially 25,000 feet per minute (7620m/min) along a path in close proximity to the cylindrically formed portion of said screenwall.
  • the present hammermill has a housing 100 enclosing the mill from a top-connected inlet 110 to a bottom discharge 200. From the bottom edges of the inlet 100, a screen wall 120 is suspended to separate the inlet 110 from the discharge 200 by virtue of the continuous disposition of the screenwall 120 from one edge to the other edge of the inlet 110.
  • the screen 120 consists of a straight portion 115 extending downwardly and diverging from the vertical centreline of the mill to a point where the straight portion 115 is tangent to and smoothly blends into a cylindrical portion 113 which curves downward and then upward again in a smooth circular path until it reaches another point of tangency with another straight portion 115 which converges to the opposite edge of the inlet 110 from the starting point.
  • the upper portions of straight portions 115 of the screen 120 may not be perforated since grinding does not take place adjacent the inlet above a grain deflector 90.
  • the deflector 90 serves to prevent grains and particles from being driven upwardly into the inlet 110 by impacts with a hammer 140 travelling upwardly at the right side of the illustrated mill.
  • a plurality of hammers 140 are pivotally mounted on hammer support pivot pins 135 and swing freely about the pins 135 which are symmetrically disposed about the peripheries of rotor discs 130 which are mounted upon and rotate with a rotatably driven shaft 125. When the rotor is rotating, the outboard tips of the hammers 140 travel along a path in close proximity to the screen 120.
  • the space between the outer surfaces of the discs 130 and screenwall 120 defines the grinding chamber 150 in which comminution of the grain occurs.
  • the grain has been ground to the desired particle size, it passes through the screen 120 and out of the mill through the discharge 200.
  • grain enters through the inlet 110 and is deflected leftwardly by the deflector 90 into the left side of the grinding chamber 150 where it is struck by the hammers 140, which are swinging past the screen 120 at approximately 1800 rpm, carried on the pins 135 by the discs 130 on the shaft 125, which is driven by a drive motor unit (not illustrated).
  • Figure 2(a) shows the high angle trajectory 122 required for a particle 10 to pass through small holes 20 in the screen 120
  • Figure 2(b) shows that large hole 25 will allow particles 10 through the screen 120 at a low angle trajectory. Since the trajectories indicated in Figures 2(a) and (b) are the minimum for each screen, it is clear that all particles at higher angles will pass through if they are of small enough size. To pass 500 micron particles at the low angle trajectory shown in Figure 2(b), an aperture size of about 2000 microns is required, as seen here. Thus, since the higher hammer tip speeds provided by the longer hammers 140 provide finer single-impact particle size, it follows that, even at the lower angle particle trajectories attending high speed impacts, the present hammermill will maintain practical production rates.
  • Figures 3(a), (b) and (c) show a standard (known) hammer 140, a single taper hammer 145 of the present invention, and a double taper hammer 146 of the present invention, respectively. These three configurations address the desired performance characteristics of hammers.
  • Hammer 140 is reversible so that, when one side is worn, it can be turned over to place the unworn side forward.
  • Pin hole 141 is symmetrical.
  • Single taper hammer 145 has an edge taper portion 144 on one edge between a minimum width portion 142 and a maximum width portion 143. The straight edge of portion 142 maintains the direction of impact of the hammer tangential to the arc of the tip travel.
  • the double taper of hammer 146 provides the desired reduction of hammer tip mass needed to reduce centrifugal forces.
  • the present hammermill provides for fine grinding of agricultural feed grains at practical production rates by providing hammers having increased length and, therefore, higher tip speeds at the same rotor speed (in revolutions per minute) to produce finer particle sizes in a single impact.
  • This produces fine ground particle sizes (less than 500 microns) using large apertured screens which avoids screen plugging and promotes flow of materials and air through the screen.
  • the provision of tapers on the hammer bodies also reduces centrifugal forces on the rotor components and permits operation of larger diameter grinding chambers.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Pulverization Processes (AREA)
EP94306501A 1993-09-02 1994-09-02 Broyeur agricole à marteaux et procédé de broyage fin de céréales. Withdrawn EP0641601A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US11659593A 1993-09-02 1993-09-02
US116595 1993-09-02

Publications (2)

Publication Number Publication Date
EP0641601A2 true EP0641601A2 (fr) 1995-03-08
EP0641601A3 EP0641601A3 (fr) 1995-08-16

Family

ID=22368134

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94306501A Withdrawn EP0641601A3 (fr) 1993-09-02 1994-09-02 Broyeur agricole à marteaux et procédé de broyage fin de céréales.

Country Status (2)

Country Link
EP (1) EP0641601A3 (fr)
DK (1) DK100094A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103263956A (zh) * 2013-06-05 2013-08-28 上海申德机械有限公司 一种双转子粉碎机
CN103521300A (zh) * 2013-10-17 2014-01-22 丹阳市正大油脂有限公司 一种高效水滴型锤片式粉碎机
CN113694996A (zh) * 2021-08-31 2021-11-26 江苏中意建筑材料有限公司 一种新型铝酸盐水泥制备用粉磨机

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4466376A (en) * 1982-09-29 1984-08-21 Wells Homer D Traffic cone

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3904134A (en) * 1974-05-08 1975-09-09 Robert P Olson Regrinding structure for hammermill
GB2171331A (en) * 1985-01-14 1986-08-28 Christy & Norris Ltd Improvements in and relating to mills

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103263956A (zh) * 2013-06-05 2013-08-28 上海申德机械有限公司 一种双转子粉碎机
CN103263956B (zh) * 2013-06-05 2015-06-17 上海申德机械有限公司 一种双转子粉碎机
CN103521300A (zh) * 2013-10-17 2014-01-22 丹阳市正大油脂有限公司 一种高效水滴型锤片式粉碎机
CN113694996A (zh) * 2021-08-31 2021-11-26 江苏中意建筑材料有限公司 一种新型铝酸盐水泥制备用粉磨机
CN113694996B (zh) * 2021-08-31 2022-11-15 江苏中意建筑材料有限公司 一种铝酸盐水泥制备用粉磨机

Also Published As

Publication number Publication date
EP0641601A3 (fr) 1995-08-16
DK100094A (da) 1995-03-03

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