Grinding apparatus with vertical static separators

• US 6,446,888 B1
• Filed: 11/08/2000
• Issued: 09/10/2002
• Est. Priority Date: 11/08/2000
• Status: Expired due to Fees

• Current Assignee: Williams Patent Crusher and Pulverizer Company
• Original Assignee: Williams Patent Crusher and Pulverizer Company
• Inventors: Williams, Robert M. Sr.
• Primary Examiner(s): Rosenbaum, Mark
• Application Number:
  US09/708,844
• Time in Patent Office: 671 Days
• Field of Search: 241/79.1, 241/80, 241/97
• US Class Current: 241/79.1
• CPC Class Codes: B02C 15/001 Air flow directing means positioned on the periphery of the horizontally rotating milling surface
• CPC Class Codes: B02C 15/02 Centrifugal pendulum-type mills
• CPC Class Codes: B02C 2015/002 combined with a classifier

Abstract

An improvement to the conventional grinding mill and separator designs which facilitates the use of larger diameter grinding surfaces and additional numbers of grinding rollers by equalizing the gas velocity around the grinding rollers and journal with the gas velocity employed to fluidize the feed particulate material. A plurality of peripheral vertical static separators are located about the grinding chamber and above the grinding rollers to provide an increase in the cross-sectional area of the grinding mill vertical shaft, thereby reducing the gas velocity around the grinding rollers and journal. The peripheral vertical static separators are configured with a trapezoidal sectional area, such that oversize particulate material falling into the peripheral vertical static separators is redirected into the grinding chamber, resulting in an increase in the number of grinding chamber material introduction points. Centrifugal action of the grinding journal ejects oversize particulate material directly into the peripheral vertical static separators before it reaches the separator chamber, thereby functioning as a first stage separator and permitting the separator chamber to be run at a slower speed, reducing overall power consumption.

Claims

1. In an apparatus for grinding material to predetermined fineness in a grinding chamber having a circumferential wall supporting a grinding surface, grinding rollers mounted in the grinding chamber to grind material against said grinding surface, material feed mechanisms configured to introduce particulate material into the grinding chamber, an air bustle surrounding the grinding chamber and receiving a supply of air or other fluidizing gas, and a plurality of openings to and spaced around the circumferential wall of the grinding chamber through which the air or other fluidizing gas in the air bustles passes to convey the particulate material upward past the grinding rollers and grinding surface, the improvement characterized by:

at least one peripheral vertical static separator formed in the circumferential wall of said grinding chamber, said peripheral vertical static separator sized to enlarge the cross-sectional area of said grinding chamber through which said air or fluidizing gas conveys said ground particulate material, wherein an upward velocity of said air or fluidizing gas past said grinding rollers is substantially equivalent to a velocity of said air or fluidizing gas upon entering said grinding chamber.

2. The improvement set forth in claim 1 wherein said at least one peripheral vertical static separator is continuous about the circumference of said circumferential wall of said grinding chamber.

3. The improvement set forth in claim 1 wherein said at least one peripheral vertical static separator includes upper and lower surfaces, said upper and lower surfaces configured to redirect impinging particulate material into said grinding chamber.

4. The improvement set forth in claim 1 wherein said at least one peripheral vertical static separator includes first and second end walls, said first and second end walls configured to redirect impinging particulate material into said grinding chamber.

5. In an apparatus for grinding material to predetermined fineness in a grinding chamber having a circumferential wall supporting a grinding surface, grinding rollers mounted in the grinding chamber to grind material against said grinding surface, material feed mechanisms configured to introduce particulate material into the grinding chamber, an air bustle surrounding the grinding chamber and receiving a supply of air or other fluidizing gas, and a plurality of openings to and spaced around the circumferential wall of the grinding chamber through which the air or other fluidizing gas in the air bustles passes to convey the particulate material upward past the grinding rollers and grinding surface to a separator chamber wherein oversize particulate material is separated, the improvement characterized by:

at least one return pathway for said separated oversize particulate material which is isolated from said upward conveyed particulate material in the separator chamber, said return pathway terminating in at least one peripheral vertical static separator formed in the circumferential wall of said grinding chamber adjacent the grinding rollers, said peripheral vertical static separator sized to enlarge the cross-sectional area of said grinding chamber through which said air or fluidizing gas conveys said ground particulate material, wherein an upward velocity of said air or fluidizing gas past said grinding rollers is substantially equivalent to a velocity of said air or fluidizing gas upon entering said grinding chamber.

6. The improvement set forth in claim 5 wherein said at least one peripheral vertical static separator is continuous about the circumference of said circumferential wall of said grinding chamber.

7. The improvement set forth in claim 5 wherein said at least one peripheral vertical static separator includes upper and lower surfaces, said upper and lower surfaces configured to redirect impinging particulate material into said grinding chamber.

8. The improvement set forth in claim 5 wherein said at least one peripheral vertical static separator includes first and second end walls, said first and second end walls configured to redirect impinging particulate material into said grinding chamber.

9. In a material separator apparatus for classifying ground material discharged from a grinding chamber into fine and oversize particles, having a material grinding mechanism receiving material to be ground and an outlet for ground material, a separator operably connected to the outlet of said grinding mechanism for receiving the ground material to be classified, and an enclosure in the separator having an outlet formed with an internal space in which the ground material is classified and an external space communicating with said internal space, the improvement comprising:

at least one peripheral vertical static separator formed in a circumferential wall of said grinding chamber, said peripheral vertical static separator in communication with said external space and sized to enlarge the cross-sectional area of said grinding chamber through which said air or fluidizing gas conveys said ground particulate material, wherein an upward velocity of said air or fluidizing gas conveying said ground material into said separator is substantially equivalent to a velocity of said air or fluidizing gas upon entering said grinding chamber.

10. An apparatus for grinding particulate material to predetermined fineness comprising:

a grinding chamber having a circumferential wall supporting a grinding surface, said circumferential wall having at least one opening formed therein through which fluidizing gas can pass to convey the particulate material upward past the grinding rollers and grinding surface;

apparatus for introducing fluidizing gas into said grinding chamber;

grinding rollers mounted in the grinding chamber to grind particulate material against said grinding surface;

at least one material feed mechanism configured to introduce particulate material into the grinding chamber; and

a first stage separator comprising at least one peripheral vertical separator on the grinding chamber wherein oversize particulate material is separated and directed back to the grinding rollers.

11. The apparatus of claim 10 further comprising a second stage separator at an outlet of the grinding chamber wherein oversize particulate material is separated and directed back to the grinding rollers.

12. In an apparatus for grinding material to predetermined fineness in a grinding chamber having a circumferential wall supporting a grinding surface, grinding rollers mounted in the grinding chamber to grind material against said grinding surface, material feed mechanisms configured to introduce particulate material into the grinding chamber, an air bustle surrounding the grinding chamber and receiving a supply of air or other fluidizing gas, and a plurality of openings to and spaced around the circumferential wall of the grinding chamber through which the air or other fluidizing gas in the air bustles passes to convey the particulate material upward past the grinding rollers and grinding surface, the improvement characterized by:

means for enlarging the cross-sectional area of said grinding chamber through which said air or fluidizing gas conveys said ground particulate material, whereby an upward velocity of said air or fluidizing gas past said grinding rollers is substantially equivalent to a velocity of said air or fluidizing gas upon entering said grinding chamber.