GB2070576A - Construction of chutes and bunkers for material handling - Google Patents

Abstract

A material conveying length of spiral configuration forming a part of a chute or of a bunker, is formed in such a way that the material support surface (16) is curved in cross-section and meets a cylindrical surface (18) defining the outermost diameter of the spiral at an obtuse angle. The curved cross-section is preferably a circular arc, the tangent to the arc at the inside edge of the cross-section being horizontal. This shape is said to help reduce the amount of material remaining on the length. <IMAGE>

Description

SPECIFICATION Construction of chutes and bunkers for material handling The invention relates to the construction of chutes and bunkers for material handling.

There are many instances where chutes and bunkers for coal handling require to have spiral lengths down which the material is to fall. It has in the past been usual to form these as flat spirals, that is to say, at every transverse section through the spiral the material support surface has been horizontal and has met a vertical cylindrical wall surrounding the spiral at a right angle. In other words, such spirals have had the form of a fairground helter-skelter.

It has been found that previously used.spirals of this kind have tended to retain a certain amount of material on them unless the helix angle of the spiral has been very great. The object of the invention is to at least alleviate this drawback. A further object of the invention is to provide a form of spiral by means of which coal can be more gently handled, that is to say by means of which its rate of travel is reduced so that the larger pieces of coal do not tend to be broken up into smaller pieces.

According to one aspect of the invention, there is provided a material conveying length of spiral configuration forming a part of a chute or of a bunker, the spiral being such that at every transverse section the material support surface is curved and meets a cylindrical surface defining the outermost diameter of the spiral at an obtuse angle. Preferably, the material support surface will be such that at every transverse section through the spiral it defines a lower part of a circle, the lowermost part of the circle preferably coinciding with the radially inner edge of the spiral. The spiral may be formed by a plurality of segments joined together by welding.

According to a further aspect of the invention, there is provided a chute or bunker for material handling, the chute or bunker having a material conveying length of spiral configuration as referred to above.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Fig. 1 is a partly cut-away side view of a bunker embodying the invention for use in coal handling plant, Fig. 2 is a diagrammatic transverse section through a spiral configuration within the bunker, and Fig. 3 is a perspective view illustrating the manner in which the spiral configuration has been formed.

Referring now to Fig. 1 of the drawings, the bunker there illustrated is of generally cylindrical upstanding shape with a frusto-conical lower portion 1Q leading to an outlet aperture 12.

Within the bunker there is disposed a material conveying length 1 4 of spiral configuration, the spiral being such that, as shown in Fig. 2, at every tranverse section the material support surface 1 6 is curved and meets a cylindrical surface 1 8 defining the outermost diameter of the spiral at an obtuse angle. The material support surface, at every transverse section through the spiral, defines a lower part of a circle, the lowermost part of the circle coinciding with the radially inner edge of the spiral.

Referring now to Fig. 3, which is a perspective view of the spiral configuration before it has been installed in the cylindrical casing of the bunker, it will be seen that the spiral has been formed by a plurality of segments 20 joined together by welding. One of the legs 22 on which the bunker is to stand is also visible in Fig. 3, as is one of a number of circular hoops 24 which brace the legs together.

It has been found that by virtue of the invention and without increasing the helix angle of the spiral, it has been possible to reduce the amount of material tending to remain on the spiral this being because at all points radially outwards of the inner diameter of the spiral the effective slope of the material support surface is greater than the helix angle. The rate of travel of the material has also been reduced to a minimum so that when the material being handled is coal, the larger pieces of coal have not tended tq become broken up into smaller pieces.

Various modifications can be made. For example, it will be understood that the invention can be applied to chutes and bunkers with or without an outer cylindrical casing. Although intended mainly for coal handling plant the invention could also be applied to plant for handling other materials.

1. A material conveying length of spiral configuration forming a part of a chute or of a bunker, the spiral being such that at every transverse section the material support surface is curved and meets a cylindrical surface defining the outermost diameter of the spiral at an obtuse angle.

2. A material conveying length according to claim 1, in which the material support surface is such that at every transverse section through the spiral it defines a lower part of a circle, the lowermost part of the circle coinciding with the radially inner edge of the spiral.

3. A material conveying length according to either one of the preceding claims, in which the spiral is formed by a plurality of segments joined together by welding.

4. A chute or bunker for material handling, the chute or bunker having a material conveying length of spiral configuration according to any one of the preceding claims.

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

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Construction of chutes and bunkers for material handling The invention relates to the construction of chutes and bunkers for material handling. There are many instances where chutes and bunkers for coal handling require to have spiral lengths down which the material is to fall. It has in the past been usual to form these as flat spirals, that is to say, at every transverse section through the spiral the material support surface has been horizontal and has met a vertical cylindrical wall surrounding the spiral at a right angle. In other words, such spirals have had the form of a fairground helter-skelter. It has been found that previously used.spirals of this kind have tended to retain a certain amount of material on them unless the helix angle of the spiral has been very great. The object of the invention is to at least alleviate this drawback. A further object of the invention is to provide a form of spiral by means of which coal can be more gently handled, that is to say by means of which its rate of travel is reduced so that the larger pieces of coal do not tend to be broken up into smaller pieces. According to one aspect of the invention, there is provided a material conveying length of spiral configuration forming a part of a chute or of a bunker, the spiral being such that at every transverse section the material support surface is curved and meets a cylindrical surface defining the outermost diameter of the spiral at an obtuse angle. Preferably, the material support surface will be such that at every transverse section through the spiral it defines a lower part of a circle, the lowermost part of the circle preferably coinciding with the radially inner edge of the spiral. The spiral may be formed by a plurality of segments joined together by welding. According to a further aspect of the invention, there is provided a chute or bunker for material handling, the chute or bunker having a material conveying length of spiral configuration as referred to above. In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Fig. 1 is a partly cut-away side view of a bunker embodying the invention for use in coal handling plant, Fig. 2 is a diagrammatic transverse section through a spiral configuration within the bunker, and Fig. 3 is a perspective view illustrating the manner in which the spiral configuration has been formed. Referring now to Fig. 1 of the drawings, the bunker there illustrated is of generally cylindrical upstanding shape with a frusto-conical lower portion 1Q leading to an outlet aperture 12. Within the bunker there is disposed a material conveying length 1 4 of spiral configuration, the spiral being such that, as shown in Fig. 2, at every tranverse section the material support surface 1 6 is curved and meets a cylindrical surface 1 8 defining the outermost diameter of the spiral at an obtuse angle. The material support surface, at every transverse section through the spiral, defines a lower part of a circle, the lowermost part of the circle coinciding with the radially inner edge of the spiral. Referring now to Fig. 3, which is a perspective view of the spiral configuration before it has been installed in the cylindrical casing of the bunker, it will be seen that the spiral has been formed by a plurality of segments 20 joined together by welding. One of the legs 22 on which the bunker is to stand is also visible in Fig. 3, as is one of a number of circular hoops 24 which brace the legs together. It has been found that by virtue of the invention and without increasing the helix angle of the spiral, it has been possible to reduce the amount of material tending to remain on the spiral this being because at all points radially outwards of the inner diameter of the spiral the effective slope of the material support surface is greater than the helix angle. The rate of travel of the material has also been reduced to a minimum so that when the material being handled is coal, the larger pieces of coal have not tended tq become broken up into smaller pieces. Various modifications can be made. For example, it will be understood that the invention can be applied to chutes and bunkers with or without an outer cylindrical casing. Although intended mainly for coal handling plant the invention could also be applied to plant for handling other materials. CLAIMS

1. A material conveying length of spiral configuration forming a part of a chute or of a bunker, the spiral being such that at every transverse section the material support surface is curved and meets a cylindrical surface defining the outermost diameter of the spiral at an obtuse angle.

2. A material conveying length according to claim 1, in which the material support surface is such that at every transverse section through the spiral it defines a lower part of a circle, the lowermost part of the circle coinciding with the radially inner edge of the spiral.

3. A material conveying length according to either one of the preceding claims, in which the spiral is formed by a plurality of segments joined together by welding.

4. A chute or bunker for material handling, the chute or bunker having a material conveying length of spiral configuration according to any one of the preceding claims.

5. A material conveying length of spiral configuration and forming a part of a chute or of a bunker, the conveying length being constructed, and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.