RU2118571C1 - Air classifier for separation of loose materials - Google Patents

Abstract

FIELD: material classification machinery and equipment. SUBSTANCE: this relates to devices intended for separation of loose materials according to size of particles by means of air currents and can be used in metallurgical, construction, chemical, mining industries and other branches of national economy. Air classifier has following components: working chamber with bottom which is permeable for air, vertical flat side walls, open discharge end and convex curvilinear covering, classification chamber with open bottom and receiving end. Classification chamber is located above receivers of products to be separated. Working chamber is conjugated by its open discharge end with open receiving end of classification chamber. Width of working chamber is selected to be by order of magnitude less than height of discharge end, and height of working chamber is selected to be not less than length of working chamber. Air current delivered to working chamber takes particles of loose material, thus creating fluidized bed. Covering of specific configuration ensures turning of air current with material to horizontal direction. Currents moving along covering and located in upper part of discharge end have substantial higher velocities than those of lower currents. Air current in classification chamber is shaped in the form of tail where heavier particles are settling in classification receivers closer to discharge end. Length of tail can reach 6 m which allows to determine exact boundaries where materials are separated. Aforesaid embodiment of air classifier allows for separation of dry powder-like materials into larger number of fractions and at high accuracy. EFFECT: higher efficiency. 1 dwg

Description

 The invention relates to a device for the separation of bulk materials by size, particle shape and specific gravity using air flows and can be used in metallurgical, construction, chemical, mining and other industries related to the use of bulk materials.

 Air classifiers are known, for example, by a.s. USSR NN 1692677, 1643117, 1632510, 1505603, 1470359, 1445821. These devices are complex, designed mainly for a homogeneous material and allow rough separation of the source material into two or three fractions, they do not provide the ability to control and obtain the final product in a narrow, advance a given range of sizes or densities.

 The prototype of the proposed solutions selected air classifier (separator) by a. from. USSR N 1685555. This air classifier contains a working chamber (trough) with an air-permeable bottom (for example, of a porous material), side walls (convex and curved), an open discharge end and a ceiling (cover); a device for supplying air located under the working chamber (trough); loading device mounted above the working chamber; receivers of separation products located at the discharge end of the working chamber, as well as a device for changing the angle of inclination of the working chamber.

 Material from the loading device is fed to a wide part of the gutter. Under the action of compressed air entering through the porous bottom, the material is fluidized and flows to a narrow part of the trench, gaining a layer height, while the material is stratified by size: the larger fractions are concentrated in the lower layers of the stream, and the smaller ones in the upper layers, then the fractions are unloaded receivers. To increase separation accuracy, these receivers should be narrow enough.

 Therefore, in the known solution, a rather crude separation of the initial product into two to three fractions is carried out.

 The proposed air classifier allows us to solve the problem of separating powdered dry materials into a large number of fractions or sizes with high accuracy and to provide the ability to control the separation range.

 The proposed air classifier, as well as the prototype, contains a working chamber with an air-permeable bottom, side walls, an open discharge end and a ceiling, an air supply device located under the bottom of the working chamber, a loading device mounted above the working chamber, receivers of separation products located at the discharge end of the working chamber, as well as a device for changing the angle of inclination of the working chamber.

 The difference is that the air classifier further comprises a classification chamber with an open bottom and a receiving end located above the separation product receivers and conjugated by an open receiving end with an open unloading end of the working chamber, the side walls of which are made vertical flat, and the working chamber overlaps between the upper rib open unloading end and the opposite edge of the bottom is made convex curved, the width of the working chamber is an order of magnitude smaller than the height of the unloading end And the height - not less than the length of the working chamber.

 The technical result obtained by carrying out the invention is achieved by using the totality of all the features (both new and known) and consists in increasing the accuracy of separation of bulk materials by size (shape, specific gravity) and increasing the number of separation classes.

 The drawing shows the proposed air classifier, which contains a working chamber 1 with a permeable to air bottom 2 vertical flat side walls 3; open unloading end 4, overlap 5, air supply device 6, located under the working chamber 1, loading device 7, installed above the working chamber 1, separation product receivers 8 located at the unloading end 4, a device for changing the angle of inclination of the working chamber 9, classification chamber 10 with an open bottom and an open receiving end 11 located above the receivers of separation products 8 and conjugated by an open receiving end 11 with an open discharge end 4 of the working chamber 1.

 The bottom 2 of the working chamber 1 is made in a specific example in the form of a frame 12 with a mesh. The frame 12 can be interchangeable to install grids (or porous material) of different denominations. The overlap 5 between the upper edge of the open discharge end 4 and the opposite edge of the bottom 2 is made convex curved. This form of overlap and the execution of the side walls vertically flat during the movement of air in the working chamber 1 exclude the occurrence of turbulent flows.

 The width of the working chamber of classifier 1 is selected by an order of magnitude smaller than the height of the unloading end 4, and the height is not less than the length of the working chamber. The first ratio creates a fluidized bed of material with minimal air flow, and the second - uniform rotation of the mixture in the horizontal direction.

 Air classifier works as follows. Air is supplied from the device for supplying air 6 to the working chamber 1 through a permeable bottom 2, for example, through a frame 12 with a mesh.

 The dry bulk material intended for separation is fed through the loading device 7 into the working chamber 1. Particles of bulk material are picked up by the air flow, and a fluidized bed is created in the working chamber 1.

 Curved overlap 5 provides for the rotation of the air flow with the material in the horizontal direction, and the flows moving along the overlap and located in the upper part of the discharge end 4 have a much greater speed than the lower flows. The material at the time of passage of the unloading end 4 is distributed in the streams in such a way that the heavier (or irregularly shaped) particles were located in the lower streams and had a lower speed, and the lighter (or regular form) had a higher speed and were carried away by the upper streams. The air flow in the classification chamber 10 is formed in the form of a loop, where heavier (larger) particles settle in the receivers of the separation products 8 closer to the receiving end 11, and carries the lighter (smaller) air further. The length of the loop can reach 6 m, which allows you to set the exact boundaries of the separation of the material.

 Setting the air classifier is carried out by changing the angle of inclination of the working chamber 1 and the amount of air supplied to the working chamber. Bulk material can be separated (classified) by size, shape and specific gravity of the particles.

Claims (1)

 An air classifier for separating bulk materials, including a working chamber with an air-permeable bottom, side walls, an open discharge end and a ceiling, an air supply device located under the bottom of the working chamber, a loading device mounted above the working chamber, separation products receivers located at the unloading end of the working chamber, as well as a device for changing the angle of inclination of the working chamber, characterized in that it further comprises a classification chamber AI with an open bottom and a receiving end located above the receivers of separation products, and an open receiving end conjugated with an open unloading end of the working chamber, the side walls of which are made vertical flat, and the overlapping of the working chamber between the upper edge of the open unloading end and the opposite bottom edge is made convex curved , the width of the working chamber is an order of magnitude smaller than the height of the discharge end, and the height is not less than the length of the working chamber.