GB2094663A - Crush roll pair for relatively soft material such as coal - Google Patents

Abstract

A crush roll pair (1, 2) for relatively soft material such as coal, the surfaces of said rolls being provided with tooth rings (3, 4) affixed in annular configuration. The rolls rotate at different peripheral velocities in opposite directions, whereby the interspace of the rolls constitutes the nip of a crusher. The tooth rings (3, 4) on different rolls (1, 2) are located to be intercalated with each other. <IMAGE>

Description

SPECIFICATION Crush roll pair for relatively soft material such as coal The present invention concerns a pair of crush rolls for relatively soft material such as coal, the surfaces of said rolls being provided with annularly affixed tooth rings, and said rolls rotating with different circumferential speeds in opposite directions, whereby the interspace of the rolls constitutes the crusher throat.

A pair of rolls of this type known in the art is disclosed for instance in the German application print No. 27 02 177. The drawback encumbering the roll pair of prior art is that the teeth on the rolls must have large enough intervals in the peripheral direction to leave space therebetween for the teeth of the opposed roll, with the result that the teeth are few in number. The greater the peripheral velocity differential between the rolls, the larger must the peripheral spacing of the teeth be. The peripheral velocities of the rolls must also be synchronized so that the teeth on the two rolls might not collide.

The object of the present invention is to eliminate the drawbacks mentioned. The crush roll pair of the invention is characterized in that the tooth rings of the two rolls are intercalated with each other.

It is possible by the aid of the invention to construct the shell surfaces of the rolls to be full of crushing teeth. Since the teeth are intercalated it is achieved that the coal particle to be crushed is subjected to combined compression and shearing effect. The shearing force has been boosted by the different circumferential velocity, known in itself in the art. The teeth of one crush roll pass by the teeth of the other crush roll and at this stage the coal will be sheared. It has been found that expressly the shearing effect is advantageous in coal crushing. It becomes possible to comminute the coal with low energy expenditure.

One favourable embodiment of the invention is characterized in that the teeth of the roll rotating with higher peripheral velocity have a chamfered trailing surface. As a result, pieces of coal impacted between teeth will be detached with greater ease and will not remain jammed.

The invention is described in the following with the aid of an example with reference to the attached drawing, wherein:- Figure 1 presents the crush roll pair in end view.

Figure 2 presents the crush roll pair in front view.

The surfaces of the rolls 1,2 have been provided with tooth rings 3,4 affixed in annular configuration.

The rolls 1, 2 rotate with different peripheral velocities in opposite directions. The smaller roll rotatets in Figure 1 clockwise and the larger roll rotates counterclockwise with higher peripheral velocity.

The interspace of rolls 1,2 constitutes the crusher throat. The tooth rings 3, 4 of different rolls 1, 2 are intercalated as Figure 2 reveals. The trailing surface 5 of the teeth on the roll 2 rotating with higher peripheral velocity is chamfered, whereby pieces of coal impacted in the interval will come loose more easily. Owing to the great number of teeth on the surfaces of rolls 1, 2, the rolls present a great abundance of cutting edges. The larger crush roll 2 has a peripheral velocity higher than that of the smaller roll. Since the smaller crush roll 1 has teeth with rectangular shape as seen from the side, their trailing edge constitutes a cutting edge too. The throat defined by the rolls 1, 2 presents quite markedly more numerous teeth and edges compared with any design of prior art.

It is self-evident to any person skilled in the art that various embodiments of the invention may vary within the scope of the claims following below.

1. Crush roll pair (1, 2) for relatively soft material such as coal, the surfaces of said rolls being provided with tooth rings (3, 4) affixed in annular configuration, and the rolls rotating with different peripheral velocities in opposite directions, characterized in that the tooth rings (3, 4) on different rolls (1, 2) are located so asto be mutually intercalated.

2. Crush roll pair according to claim 1,characte- rized in that the trailing surface (5) of the teeth on the roll (2) rotating with higher peripheral velocity are chamfered.

3. Crush roll pair substantially as described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Crush roll pair for relatively soft material such as coal The present invention concerns a pair of crush rolls for relatively soft material such as coal, the surfaces of said rolls being provided with annularly affixed tooth rings, and said rolls rotating with different circumferential speeds in opposite directions, whereby the interspace of the rolls constitutes the crusher throat. A pair of rolls of this type known in the art is disclosed for instance in the German application print No. 27 02 177. The drawback encumbering the roll pair of prior art is that the teeth on the rolls must have large enough intervals in the peripheral direction to leave space therebetween for the teeth of the opposed roll, with the result that the teeth are few in number. The greater the peripheral velocity differential between the rolls, the larger must the peripheral spacing of the teeth be. The peripheral velocities of the rolls must also be synchronized so that the teeth on the two rolls might not collide. The object of the present invention is to eliminate the drawbacks mentioned. The crush roll pair of the invention is characterized in that the tooth rings of the two rolls are intercalated with each other. It is possible by the aid of the invention to construct the shell surfaces of the rolls to be full of crushing teeth. Since the teeth are intercalated it is achieved that the coal particle to be crushed is subjected to combined compression and shearing effect. The shearing force has been boosted by the different circumferential velocity, known in itself in the art. The teeth of one crush roll pass by the teeth of the other crush roll and at this stage the coal will be sheared. It has been found that expressly the shearing effect is advantageous in coal crushing. It becomes possible to comminute the coal with low energy expenditure. One favourable embodiment of the invention is characterized in that the teeth of the roll rotating with higher peripheral velocity have a chamfered trailing surface. As a result, pieces of coal impacted between teeth will be detached with greater ease and will not remain jammed. The invention is described in the following with the aid of an example with reference to the attached drawing, wherein:- Figure 1 presents the crush roll pair in end view. Figure 2 presents the crush roll pair in front view. The surfaces of the rolls 1,2 have been provided with tooth rings 3,4 affixed in annular configuration. The rolls 1, 2 rotate with different peripheral velocities in opposite directions. The smaller roll rotatets in Figure 1 clockwise and the larger roll rotates counterclockwise with higher peripheral velocity. The interspace of rolls 1,2 constitutes the crusher throat. The tooth rings 3, 4 of different rolls 1, 2 are intercalated as Figure 2 reveals. The trailing surface 5 of the teeth on the roll 2 rotating with higher peripheral velocity is chamfered, whereby pieces of coal impacted in the interval will come loose more easily. Owing to the great number of teeth on the surfaces of rolls 1, 2, the rolls present a great abundance of cutting edges. The larger crush roll 2 has a peripheral velocity higher than that of the smaller roll. Since the smaller crush roll 1 has teeth with rectangular shape as seen from the side, their trailing edge constitutes a cutting edge too. The throat defined by the rolls 1, 2 presents quite markedly more numerous teeth and edges compared with any design of prior art. It is self-evident to any person skilled in the art that various embodiments of the invention may vary within the scope of the claims following below. CLAIMS

1. Crush roll pair (1, 2) for relatively soft material such as coal, the surfaces of said rolls being provided with tooth rings (3, 4) affixed in annular configuration, and the rolls rotating with different peripheral velocities in opposite directions, characterized in that the tooth rings (3, 4) on different rolls (1, 2) are located so asto be mutually intercalated.

2. Crush roll pair according to claim 1,characte- rized in that the trailing surface (5) of the teeth on the roll (2) rotating with higher peripheral velocity are chamfered.

3. Crush roll pair substantially as described with reference to the accompanying drawing.