GB2091588A

GB2091588A - Shredding machine

Info

Publication number: GB2091588A
Application number: GB8102115A
Authority: GB
Original assignee: Dresser Europe SPRL
Current assignee: Dresser Europe SPRL
Priority date: 1981-01-23
Filing date: 1981-01-23
Publication date: 1982-08-04
Also published as: GB2091588B

Abstract

A shredding machine comprises a pair of shafts rotatable in opposite directions about parallel, horizontal axes, each shaft carrying a plurality of axially spaced discs of greater diametral dimensions than the shafts and provided with peripheral cutter teeth. The discs of one shaft interdigitate with the discs of the other shaft. A material infeed mouth is defined by mutually converging upper peripheries of the discs and a material discharge opening is defined by mutually diverging lower peripheries of the discs. A static cleaning comb 12 is located adjacent each shaft and incorporates projecting tines which interdigitate with the adjacent discs and terminate adjacent the shaft periphery, below the shaft axis. <IMAGE>

Description

SPECIFICATION Shredding machine This invention relates to a machine for the treatment of material such as domestic refuse, minerals etc. by a shredding, comminuting, shearing etc. action (all hereinafter referred to as shredding).

Known shredding machines comprise a pair of shafts rotatable in opposite directions about parallel, horizontal axes, each shaft carrying a plurality of axially spaced discs of greater diametral dimensions than the shafts and provided with peripheral cutter teeth, the discs of one shaft interdigitating with the discs of the other shaft and the material to be treated being fed to a mouth defined by mutually converging upper peripheries of the discs and emerging from mutually diverging lower peripheries of the discs at a discharge opening.

Such machines have proved acceptable in the shredding of certain materials e.g. tin cans, tyres, etc., which exhibit no adhesive characteristics.

However, with materials such as washed coal, filter cake, paper, plastics etc., difficulties are encountered in achieving a satisfactory throughput and sized product, due to the inherently adhesive nature of the materials.

According to the present invention, there is provided a shredding machine comprising a pair of shafts rotatable in opposite directions about parallel, horizontal axes, each shaft carrying a plurality of axially spaced discs of greater diametral dimensions than the shafts and provided with peripheral cutter teeth, the discs of one shaft interdigitating with the discs of the other shaft ahd a material infeed mouth defined by mutually converging upper peripheries of the discs and a material discharge opening defined by mutually diverging lower peripheries of the discs, a static cleaning comb located adjacent each shaft and incorporating projecting tines which interdigitate with the adjacent discs and terminate adjacent the shaft periphery, below the shaft axis.

Thus, with the shredding machine in accordance with the invention, a stripping effect on the shredded material is produced by the combs, whereby any shredded material tending to adhere between the discs and/or to the shafts is stripped therefrom and discharged rather than being carried around to the infeed mouth.

Preferably, the horizontal axes are located in a common horizontal plane. Combs can additionally be located above the shaft axes to prevent feed material spilling down the back of the discs in the event of shaft and disc reversal or other such circumstance. Furthermore, tines of each comb are preferably of steel.

Although all the discs of both shafts may be of the same diameter, it is preferred for the discs of one shaft to be of greater diametral dimensions than those of the other shaft. Furthermore, each shaft which, together with its discs, constitutes a rotor, is preferably carried in a frame which may be pivotally attached to a base member and swingable e.g. under the control of hydraulic rams, from inner, operational positions to outer servicing posltions.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an end elevation, with outer casing removed for clarity, of a shredding machine in accordance with the invention; Figure 2 is a part sectional side elevation of Figure 1; and Figures 3 and 4 correspond to Figure 1 but show the frame parts of the machine in their inner and outer positions, respectively.

Material to be shredded enters through a feed opening at the top of the main central housing 1, being supplied in a controlled manner by a feed regulating device such as a conveyor (not shown), and is allowed to fall directly into the feed mouth defined by the contrarotating rotors 6, each comprising a shaft and a plurality of axially spaced discs, the shaft axes being located in a common horizontal plane and the discs of one shaft firstly peripherally interdigitating with the discs of the other shaft and secondly having differing diametral dimensions. At the feed mouth the teeth on the discs push the material down to the numerous intersections of the peripheries of the discs on the two rotors 6, where the material is shredded and forced to pass into the space between the rotors 6 above spacing elements 9.

The shaft axes are so spaced that the contra rotation of the two rotors 6 combined with the passing action of the material between the discs allows annuli of material to be formed over the spacing elements.

This material then revolves with the shafts until it is stripped from its position and pushed out of the space between the discs by cleaning combs 1 2 that are situated beneath and nearly touching the shaft peripheries beyond the discharge opening of the shredding machine. This material having been sized becomes the final product from the shredding machine and is usually carried away by a conveyor (not shown) as it falls from the discharge opening.

In detail, the tines are positioned between the cutters and in close proximity to the spacing elements, being mounted on positioning pins 13 and spaced apart by spacing blocks that are always greater in thickness than the thickness of an individual disc.

From this it can be seen that correspondingly the thickness of each tine must also be thinner than the width of gap between adjacent discs or thinner than any spacing element.

1. A shredding machine comprising a pair of shafts rotatable in opposite directions about parallel, horizontal axes, each shaft carrying a plurality of axially spaced discs of greater diametral dimensions than the shafts and provided with peripheral cutter teeth, the discs of one shaft interdigitating with the discs of the other shaft, a

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Shredding machine This invention relates to a machine for the treatment of material such as domestic refuse, minerals etc. by a shredding, comminuting, shearing etc. action (all hereinafter referred to as shredding). Known shredding machines comprise a pair of shafts rotatable in opposite directions about parallel, horizontal axes, each shaft carrying a plurality of axially spaced discs of greater diametral dimensions than the shafts and provided with peripheral cutter teeth, the discs of one shaft interdigitating with the discs of the other shaft and the material to be treated being fed to a mouth defined by mutually converging upper peripheries of the discs and emerging from mutually diverging lower peripheries of the discs at a discharge opening. Such machines have proved acceptable in the shredding of certain materials e.g. tin cans, tyres, etc., which exhibit no adhesive characteristics. However, with materials such as washed coal, filter cake, paper, plastics etc., difficulties are encountered in achieving a satisfactory throughput and sized product, due to the inherently adhesive nature of the materials. According to the present invention, there is provided a shredding machine comprising a pair of shafts rotatable in opposite directions about parallel, horizontal axes, each shaft carrying a plurality of axially spaced discs of greater diametral dimensions than the shafts and provided with peripheral cutter teeth, the discs of one shaft interdigitating with the discs of the other shaft ahd a material infeed mouth defined by mutually converging upper peripheries of the discs and a material discharge opening defined by mutually diverging lower peripheries of the discs, a static cleaning comb located adjacent each shaft and incorporating projecting tines which interdigitate with the adjacent discs and terminate adjacent the shaft periphery, below the shaft axis. Thus, with the shredding machine in accordance with the invention, a stripping effect on the shredded material is produced by the combs, whereby any shredded material tending to adhere between the discs and/or to the shafts is stripped therefrom and discharged rather than being carried around to the infeed mouth. Preferably, the horizontal axes are located in a common horizontal plane. Combs can additionally be located above the shaft axes to prevent feed material spilling down the back of the discs in the event of shaft and disc reversal or other such circumstance. Furthermore, tines of each comb are preferably of steel. Although all the discs of both shafts may be of the same diameter, it is preferred for the discs of one shaft to be of greater diametral dimensions than those of the other shaft. Furthermore, each shaft which, together with its discs, constitutes a rotor, is preferably carried in a frame which may be pivotally attached to a base member and swingable e.g. under the control of hydraulic rams, from inner, operational positions to outer servicing posltions. The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an end elevation, with outer casing removed for clarity, of a shredding machine in accordance with the invention; Figure 2 is a part sectional side elevation of Figure 1; and Figures 3 and 4 correspond to Figure 1 but show the frame parts of the machine in their inner and outer positions, respectively. Material to be shredded enters through a feed opening at the top of the main central housing 1, being supplied in a controlled manner by a feed regulating device such as a conveyor (not shown), and is allowed to fall directly into the feed mouth defined by the contrarotating rotors 6, each comprising a shaft and a plurality of axially spaced discs, the shaft axes being located in a common horizontal plane and the discs of one shaft firstly peripherally interdigitating with the discs of the other shaft and secondly having differing diametral dimensions. At the feed mouth the teeth on the discs push the material down to the numerous intersections of the peripheries of the discs on the two rotors 6, where the material is shredded and forced to pass into the space between the rotors 6 above spacing elements 9. The shaft axes are so spaced that the contra rotation of the two rotors 6 combined with the passing action of the material between the discs allows annuli of material to be formed over the spacing elements. This material then revolves with the shafts until it is stripped from its position and pushed out of the space between the discs by cleaning combs 1 2 that are situated beneath and nearly touching the shaft peripheries beyond the discharge opening of the shredding machine. This material having been sized becomes the final product from the shredding machine and is usually carried away by a conveyor (not shown) as it falls from the discharge opening. In detail, the tines are positioned between the cutters and in close proximity to the spacing elements, being mounted on positioning pins 13 and spaced apart by spacing blocks that are always greater in thickness than the thickness of an individual disc. From this it can be seen that correspondingly the thickness of each tine must also be thinner than the width of gap between adjacent discs or thinner than any spacing element. CLAIMS

1. A shredding machine comprising a pair of shafts rotatable in opposite directions about parallel, horizontal axes, each shaft carrying a plurality of axially spaced discs of greater diametral dimensions than the shafts and provided with peripheral cutter teeth, the discs of one shaft interdigitating with the discs of the other shaft, a material infeed mouth defined by mutually converging upper peripheries of the discs and a material discharge opening defined by mutually diverging lower peripheries of the discs, and a static cleaning comb located adjacent each shaft and incorporating projecting tines which interdigitate with the adjacent discs and terminate adjacent the shaft periphery, below the shaft axis.

2. A machine as claimed in Claim 1, wherein the horizontal axes are located in a common horizontal plane.

3. A machine as claimed in Claim 1 or Claim 2, wherein combs are additionally located above the shaft axes to prevent feed material spilling down the back of the discs.

4. A machine as claimed in any preceding Claim, wherein the tines of the or each comb are of steel.

5. A machine as claimed in any preceding Claim, wherein all the discs of both shafts are of the same diameter.

6. A machine as claimed in any one of Claims 1 to 4, wherein the discs of one shaft are of greater diametral dimensions than those of the other shaft.

7. A machine as claimed in any preceding Claim, wherein each shaft which, together with its discs, constitutes a rotor, is carried in a frame.

8. A machine as claimed in Claim 7, wherein each frame is pivotally attached to a base member and swingable from inner, operational position to outer, servicing position.

9. A machine as claimed in Claim 8, wherein each frame is swingable under the control of a hydraulic ram.

1 0. A shredding machine, substantially as hereinbefore described with reference to the accompanying drawings.