Micronized grinding apparatus

• US 4,522,343 A
• Filed: 12/13/1982
• Issued: 06/11/1985
• Est. Priority Date: 12/13/1982
• Status: Expired due to Term

• Current Assignee: Williams Patent Crusher and Pulverizer Company
• Original Assignee: Williams Patent Crusher and Pulverizer Company
• Inventors: Williams, Robert M.
• Primary Examiner(s): Rosenbaum, Mark
• Assistant Examiner(s): Eley, Timothy V.
• Application Number:
  US06/448,950
• Time in Patent Office: 911 Days
• Field of Search: 241/53, 241/56, 241/57, 241/58, 241/61, 241/62, 241/110-119, 241/39, 241/124-129
• US Class Current: 241/58
• 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

Apparatus for grinding coal to micron fineness having a grinding chamber with a grinding surface supported by a circumferential wall in the grinding chamber, a plurality of grinding rolls orbiting in the grinding chamber for grinding the coal, air supply bustle surrounding the grinding chamber, air flow restrictor means opening from the air supply bustle to the grinding chamber to create a back pressure in the air supply bustle for substantially evenly distributing the air supplied to the grinding chamber around the circumference of the grinding chamber, and wherein the restrictor means directs the air flow tangentially relative to the circumferential wall of the grinding chamber so that the coal particles are caught up in a cyclonic movement having a large initial horizontally directed force to maintain a body of coal particles in the orbit of the grinding rolls, which horizontal force gradually diminishes as the vertical force component of the air flow lifts the ground coal particles out of the grinding chamber.

Claims

1. In an apparatus for grinding coal to micron fineness in a grinding chamber having a circumferential wall supporting a grinding surface, grinding rolls operably mounted in the grinding chamber to grind coal against said grinding surface, means for introducing coal to said grinding chamber, air bustle means surrounding the grinding chamber and receiving a supply of air, and a plurality of openings to and spaced around the circumferential wall of the grinding chamber, the improvement characterized in the mounting of air flow restrictor means in the circumferential wall openings, all of said restrictor means comprising tubes having a somewhat restricted throat like a venturi thereby presenting openings between the air bustle and the grinding chamber for directing the air flow at increased velocity into a like number of horizontal streams substantially tangentially along the circumferential wall and to cause rapid spinning of the mass of the coal particles for substantially evenly distributing coal and air along the grinding surface, and said restrictor tubes creating a back pressure on the air in the air bustle to substantially evenly distribute the air throughout the air bustle and direct the air flow at said increased velocity into the grinding chamber so as to force the mass of the coal particles to follow streams substantially tangential to the circumferential wall.

2. The improvement set forth in claim 1 characterized in that said air flow restrictor means are venturi tubes for increasing the velocity of the air flow between said air bustle and said chamber.

3. In a grinding apparatus for grinding precrushed coal to a micronized fineness and having a grinding chamber defined by a peripheral wall formed with air flow openings distributed substantially evenly around the peripheral wall and opening into the grinding chamber, grinding rolls orbiting in the grinding chamber, and an air receiving bustle surrounding the grinding chamber and enclosing the air flow openings, the improvement characterized in the arrangement of air flow directing means mounted in each of the peripheral wall air flow openings and being oriented in the peripheral wall air flow openings to impart a centrifugal spin and an increased velocity to the air as it enters the grinding chamber for presenting the mass of the coal in a substantially uniform distribution of such coal to said grinding rolls, whereby the increased velocity and centrifugal spin forces the coal movement into the orbit of the grinding rolls, and said air flow directing means in each of the peripheral wall air flow openings is a venturi tube for reducing the area of said flow openings and creating a back pressure in said bustle to assure said increased air flow velocity and centrifugal spin in the grinding chamber.