US2684813A

US2684813A - Rotating-plate and lever-mounted grinding-roll mill, with upwardlydirecting carrier-air means adjacent the plate periphery

Info

Publication number: US2684813A
Application number: US270434A
Authority: US
Inventors: Loesche Ernst-Guenther
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-02-07
Filing date: 1952-02-07
Publication date: 1954-07-27
Anticipated expiration: 1971-07-27

Description

Filed Feb. 7, 1952 y 27, 1954 ERNST-GUENTHER LOESCHE 8 3 ROTATING-PLATE AND LEVER-MOUNTED GRINDING-ROLL MILL, WITH UPWARDLY-DIRECTING CARRIER-AIR- MEANS ADJACENT THE PLATE PERIPHERY 2 Sheets-Sheet 1 y 7, 1954 ERNST-GUENTHER LOESCHE 4,313

ROTATING-PLATE AND LEVER-NOUNTED GRINDING-ROLL MILL, WITH UPWARDLY-DIRECTING CARRIER-AIR MEANS ADJACENT THE PLATE PERIPHERY Filed Feb. 7, 1952 2 Sheets-Sheet 2 V J r2221) 1512101 E. C-ZLoea Che Patented July 27, 1954 ROTATING-PLATE AND LEVER-'MOUNTED GRINDING-ROLL MILL, WITH UPWARDLY- DIRECTING CARRIER-AIR MEANS ADJA- CENT THE PLATE PERIPHERY Ernst-Guenther Loesche, Dusseldorf, Germany .Application February '1, 1952, Serial No. 270,434

2 Claims.

This invention relates to spring controlled .roller mills having a vertical axis, in which on the outside of the grindingplate there is arranged a bladed rim or similar device imparting .a Jde'sire'd direction to the current of air and having an outer ring which together with a ring provided on the casing ensures tightness. In spring .controlled roller mills of this type, the

periphery of the mill at about the height of the grinding plate. An already recognized advantage in the use of carrier air consists in the fact that this air produces sifting of the heavy and undesirable constituents of the material being ground from the other constituents thereof. In resilient roller mills of known construction, however, it was difiicult to adjust the speed of the air sufliciently accurately to render possible clear separation of the constituents of the material being ground.

The invention consists in a resilient-roller mill in which the current of air enters through openings arranged somewhat below the grinding plate. This current of air is then guided through specially shaped channels under the grinding plate and then passes through a bladed rim provided on the outside of the grinding plate, or through a similar device imparting a desired direction to the air stream, into the space above the grinding table, and there takes with it the material which has been sufiiciently finely ground.

In one preferred embodiment of the invention, downwardly inclined discharge passages are arranged in the base of the spring controlled roller mill, and the channels disposed under the grinding table slope downwards towards these discharge passages. Thus, undesired constituents such as pieces of iron and the like, which because of their high specific gravity cannot be carried away by the carrier air, can collect in the discharge passages and be emptied out from time to time.

One embodiment of the invention is illustrated by way of example in the accompanying drawings, in which:

Figure 1 is a view of a roller mill in section, certain parts being shown in elevation,

Figure 2 is a plan view, in section on section plane 22 of Figure 1,

Figure 3 is a side view, in elevation, of the resilient roller mill illustrated in section in Figure 1, and

Figure 4 is a view in elevation, on a larger scale, corresponding to a portion of Figure l, certain parts being shown in section.

Cir

:entryof the carrier air took place along the 2 The main components of the spring controlled roller mill illustrated in Figure 1 consist of a basen, which in the embodiment illustrated consists of concrete, but may alternatively be made of steel, a transmission mechanism 9 accommodated in the base, an air inlet 0, a grinding plate 0! driven by means of the transmission mechanism disposed underneath it, and two grinding rollers p whichroll on the rotating grinding plate 11 and are pivotally mounted on shafts 7 through the intermediary of oscillatinglevers sand resiliently pressed against the grinding plate (2 by means of a spring 1'.

As mentioned above, the entry of the carrier air takes place through openings 0 disposed on two opposite sides of the spring controlled roller mill, as shown in Figures 1 and 3. The inlet openings 0 lead into channels m disposed below the grinding plate (1. Figure 2 shows that these channels m slope downwards towards discharge passages i, two of which are disposed on each side of the spring controlled roller mill (see Figure 2). These discharge passages are each provided, at the outlet, with a flap 2; attached in a freely rotatable manner at its upper end only, whereby when fragments accumulate these flaps open spontaneously and therefore have a selfclearing action. On the periphery of the grinding plate are arranged blades 0 (see Figure 4). On the outer edge of these blades 0 is disposed a continuous ring D which projects above the top edge of the blades 0 and together with a ring 1 disposed on the casing produces tightness by reason of the fact that the ring 1 overlaps on the inside of the ring 27. The casing a is reinforced at this point by the arrangement of a plurality of plates. The ring 1 is adapted to the desired course of the current of air and is made of wear-resistant material, for instance cast electric steel. On the outer edge of the grinding plate 03 is provided a further ring it which is used for retaining the material being ground and is formed as a bulge corresponding to the desired course of the current of air, and is also made of a wear-resistant material. By means of screws 1' this ring it is arranged so as to be vertically adjustable, preferably by the insertion of make-up pieces k. The arrow in Figure 4 shows the required direction of flow of the carrier air.

The grinding plate (1 is provided with specially wear-resistant parts q fixed to the grinding plate at by means of clamping members t. In the centre of the grinding plate a truncated-conical elevation to is provided in order to prevent the accumulation of material there.

The arrangement of the grinding rollers p is as follows:

The grinding rollers are each arranged between a pair of oscillating levers s (see Figure 3). Resilient pressure of the grinding rollers p against the grinding plate (1 is efiected by a pair of springs r disposed laterally of the mill casing. Alternatively however it is possible to provide for instance one spring which in that case will pass through the mill casing itself.

I claim:

1. A spring controlled roller mill for grinding coal, limestone and like materials, comprising: a casing having lateral air inlets therein, a grinding plate mounted for rotation about a vertical axis within said casing, said grinding plate having a fiat grinding surface located above said air inlets, grinding rollers, levers carrying said grinding rollers and mounted to swing about horizontal axes to locate said rollers on said flat grinding surface in rolling contact therewith, spring means applied to said levers to press the grinding rollers against the grinding surface for grinding the material during the rotation of the grinding plate, a peripheral retaining ring on the grinding plate projecting above the grinding surface thereof, air conduits in said casing for conducting air from said air inlets to the underside of the grinding plate, said air conduits having downwardly and outwardly inclined bottom walls, peripheral blades on the outside of said grinding plate,

arranged to convey air upwardly from said air conduits to the upper side of the grinding plate, a continuous shroud ring on the outer edges of said blades, said shroud ring projecting above the top edges of the blades, a ring on the inside of the casing above said blades and overlapping the projecting part of the shroud ring, and a base under said casing having inclined discharge passages therein below said air inlets for the discharge of undesired constituents.

2. A spring controlled roller mill as set forth in claim 1, in which the retaining ring and the ring on the inside of the casing are adapted to cooperate with one another to guide the air current delivered by the blades along the desired path into the space above the grinding surface.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,473,478 Kreutzberg Dec. 25, 1923 2,112,359 Crites Mar. 29, 1938 2,206,145 Wood July 2, 1940 2,342,255 Doyle Feb. 22, 1944 2,378,681 Bailey June 19, 1945 FOREIGN PATENTS Number Country Date 428,237 Great Britain May 9, 1935