GB1568793A

GB1568793A - Screen for granular materials

Info

Publication number: GB1568793A
Application number: GB1154578A
Authority: GB
Original assignee: GLOWNE B ST P PRZEROBKI WEGLA
Current assignee: GLOWNE B ST P PRZEROBKI WEGLA
Priority date: 1977-04-09
Filing date: 1978-03-23
Publication date: 1980-06-04
Also published as: PL197341A1; FR2386360A1; DE2813989A1; DE2813989B2; PL108739B1; DE2813989C3

Description

(54) SCREEN FOR GRANULAR MATERIALS (71) We, GLOWNE BIURO STU DIOW i PROJEKTOW PRZEROBKI WEGLA "SEPARATOR" 40952 Katowice, ul. Armii Czerwonej 2, Poland, an Enterprise organised and existing under the laws of Poland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following state ment: This invention relates to a screen for dressing or screening granular materials, especially hard coal in the preliminary clas so cation process in order to isolate the finest grain classes from the fed material.

The screening of granular materials has hitherto been carried out by means of single-plane sieve decks mounted as a single-storey or multi-storey system in vibratory riddles (Stanislaw Blaschke: "Mineral dressing", Slask Publishers, Katowise 1972).

There is also known a screen for dressing granular materials (Polish Patent Application No. P-184416, published on November 6, 1976), the sieve deck of this screen consisting of at least two parallel sieve decks arranged on above the other, and there being in the upper sieve deck at least one slot extending over the entire width thereof.

Further, there are known screens wherein the screening planes are arranged in one or more screen boxes to which vibratory motions are imparted during the operation, the or each box including a number of decks disposed one above the other, and as a result there are obtained a number of screens of diminishing mesh size according to the decreasing sequence of the grain size (GFR Patent Specification No. 1,184,610; U.S. Patent Specification No. 2,572,177 and U.S. Patent Specification No. 3,347,368).

Only low output and screening efficiency can be achieved with the designs described above. As to the sieve decks composed of two sieve panels, the sole function of the upper sieve panel is to lessen the load on the lower sieve panel.

According to the present invention, we provide a screen for granular materials, comprising a vibratory housing provided with upper and lower sieve decks of the same mesh and respectively of greater and lesser widths, the upper sieve deck having therein a transverse slot extending over its full width and dividing same into two panels, directly below only one of which is a roof-shaped chute (as hereinafter defined) built in between the two sieve decks and the lower edges of which extend to outlet slots arranged along side walls of the riddle housing.

Screens in accordance with the invention bring about significant increase of the total working area, of the total width of the layer of the granular material, and also a considerable increase of the output and efficiency of screening of multi-deck screens, due to utilization of both sieve panels of the upper deck for screening, and due to continual discharge directly into a bin of material from the screening process passing the mesh of the upper sieve deck.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing, wherein: Figure 1 is a longitudinal sectional view of a screen; Figure 2 is a plan view of the screen. and Figure 3 is a cross-sectional view of the screen showing also a roof-shaped chute, i.e., a chute having two wings symmetrical about an axis from which they are downwardly inclined.

The screen illustrated in the drawing comprises a vibratory housing 1 which includes an upper sieve deck 2 and a lower sieve deck 3 built thereinto the lower sieve deck 3 being smaller in width than the upper sieve deck 2. Both decks are equipped with sieves of the same mesh.

The upper sieve deck 2 consists of two sieve panels 4 and 5 which are in the same plane and which are spaced apart to define a transverse slot 6 wherethrough can pass onto the lower sieve deck 3 apart of the material being preliminarily screened.

The transverse slot 6 is shielded at both sides of straps 7 in order that the stream of granular material passing therethrough is of the width desired to suit the lower sieve deck 3.

There are three routes of passage into the bin 11, for material fed mechanically onto the upper sieve deck 2 of the vibratory housing and passing the mesh of the decks 2 and 3. One such route is through the sieve panel 4, a second is through the slot 6 onto and through the lower sieve deck 3. and a third is through the sieve panel 5 onto the roof-shaped chute 8 where the oncoming material is divided into two streams. each flowing down one of the wings of the chute and over the lower edge of said wing into one of two outlet slots 9 and 10 formed along the side walls of the riddle.

The roof-shaped chute 8 which rests on carrying profiles 12 limited with angle sections 14, is fastened to one of the flat irons 13 of the upper sieve deck 2.

WHAT WE CLAIM IS: 1. A screen for granular materials, comprising a vibratory housing provided with upper and lower sieve decks of the same mesh and respectively of greater and lesser widths, the upper sieve deck having therein a transverse slot extending over its full width and dividing same into two panels. directly below only. one of which is roof-shaped chute (as hereinbefore defined). built in between the two sieve decks and the lower edges of which extend to outlet slots arranged along side walls of the housing.

2. A screen for granular materials. sub stantiallv as hereinbefore described with reference to the accompanying drawing.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. sieve deck 2. Both decks are equipped with sieves of the same mesh. The upper sieve deck 2 consists of two sieve panels 4 and 5 which are in the same plane and which are spaced apart to define a transverse slot 6 wherethrough can pass onto the lower sieve deck 3 apart of the material being preliminarily screened. The transverse slot 6 is shielded at both sides of straps 7 in order that the stream of granular material passing therethrough is of the width desired to suit the lower sieve deck 3. There are three routes of passage into the bin 11, for material fed mechanically onto the upper sieve deck 2 of the vibratory housing and passing the mesh of the decks 2 and 3. One such route is through the sieve panel 4, a second is through the slot 6 onto and through the lower sieve deck 3. and a third is through the sieve panel 5 onto the roof-shaped chute 8 where the oncoming material is divided into two streams. each flowing down one of the wings of the chute and over the lower edge of said wing into one of two outlet slots 9 and 10 formed along the side walls of the riddle. The roof-shaped chute 8 which rests on carrying profiles 12 limited with angle sections 14, is fastened to one of the flat irons 13 of the upper sieve deck 2. WHAT WE CLAIM IS:

1. A screen for granular materials, comprising a vibratory housing provided with upper and lower sieve decks of the same mesh and respectively of greater and lesser widths, the upper sieve deck having therein a transverse slot extending over its full width and dividing same into two panels. directly below only. one of which is roof-shaped chute (as hereinbefore defined). built in between the two sieve decks and the lower edges of which extend to outlet slots arranged along side walls of the housing.