RU2067500C1 - Loose material inertial separator - Google Patents

Abstract

FIELD: separation and sorting of materials after crushing; separation of ready product after grinding solid materials in mills. SUBSTANCE: inertial separator is provided with accumulator bell mouth 4 and guide bell mouth 5 located coaxially forming fixed circular inertial passage between walls. Distance between edges of above-mentioned bell mouths is determined from expression

, where d₁ is diameter of accumulator bell mouth at maximum section over edges and d₂ is inner diameter of cylindrical portion of separator housing. When this inertial separator is used in dust systems with counter-jet mill, power requirements for transportation of product are reduced by 75 to 80 percent. EFFECT: enhanced economical efficiency, enhanced reliability and high quality of product. 5 cl, 1 dwg

Description

 The invention relates to the category of devices for the separation and sorting of material after crushing, in particular it is used in combination with mills for grinding solid materials to separate the finished product. The device gives the greatest effect when used in combination with an anti-jet mill.

 When grinding solid materials, such as coal, cement, limestone, ore, the problem arises of separating the finished dust from the mill product. To solve it, separators of different designs and degrees of complexity are used.

 As a prototype of the alleged invention adopted the separator used in the installation of fine grinding of solid materials (ed. St. USSR N 1003894, CL B 02 C 19/00, 21/00, 1983). The separator contains a conically housing with inlet and outlet nozzles located on the same vertical axis and inserted into the drive in the form of a socket with a spatula. Moreover, the tapering part of the socket faces the inlet pipe and is connected to the estrus of the second return stage. The classification of the material in the separator occurs first in the first gravity stage due to a sharp decrease in air velocity when the air mixture flows into the annular channel between the cone and the bell, and then in the second centrifugal stage due to the twisting of the air mixture with a spatula. Finished dust fineness is controlled by turning the blades of the scapular apparatus.

 This separator has the following disadvantages: a large air flow rate necessary for the operation of the centrifugal stage, the complexity and unreliability of the drive mechanism of the blade apparatus, insufficient fineness of the finished dust.

 The aim of the invention is to increase the efficiency and reliability of the separator, as well as the quality of the finished product due to the appropriate organization of the aerodynamics of the flow of the aerosol.

 This goal is achieved by the fact that the inertial separator of bulk materials, comprising a housing with inlet pipes located on the same vertical axis in the lower part and outlets in the upper part, chutes of the first return stage provided in the lower part of the housing, and a drive installed inside the housing along the specified axis in the form the bell, the tapering part of which faces the inlet pipe and is connected to at least one estrus of the second return stage, further comprises a guide bell, setting enny coaxially with the socket drive with their walls formed between the annular inertial channel, wherein the diameter of the narrow end exceeds the diameter of the guide funnel exit end of the inlet pipe.

где d₁ диаметр раструба накопителя в максимальном сечении по кромкам;
d₂ внутреный диаметр цилиндрической части корпуса сепаратора.The generatrix of the rotation surface of each of the sockets is a smooth arc with a smoothly varying curvature. Moreover, the distance between the edges of two adjacent bells is determined from the expression:

where d _{1 the} diameter of the socket of the drive in the maximum section at the edges;
d _{2 the} inner diameter of the cylindrical part of the separator housing.

 In addition, the edges of the sockets are provided with adjustable sashes. The sockets themselves are suspended from the upper housing lid using at least three rods of adjustable length.

 The causal relationship between the hallmarks and the purpose of the invention is as follows. The presence of a guide bell, the diameter of the narrow end of which exceeds the diameter of the outlet end of the inlet pipe, and installed coaxially with the storage bell to form an annular channel, the value l of which at the exit from it between adjacent edges is determined from the expression mentioned in the formula, allows the mixture to move along a curvilinear trajectories in the presence of centrifugal forces. At the exit from the annular channel, the flow rate of the air mixture decreases many times in comparison with the input speed, and its direction becomes radially diverging in the horizontal plane. Under these conditions, solid particles in the flow lose the upward vertical component of speed.

 From this moment on, only those particles with diameters smaller than the boundary diameter, determined only by the particle velocity and equal to the flow velocity in the annular cross-section of the separator above the upper edge of the socket, are carried upward. Due to the large area of this section, tens of times greater than the sectional area of the inlet pipe, the flow rate is many times lower and all particles with a diameter larger than the boundary drop down and return to the dominus. All this makes it possible to achieve a clear classification of the mill product in the inertial separator with a multiple reduction in air flow and in proportion to energy consumption. Thus, the goal set in the invention is ensured, i.e., increasing the efficiency and reliability of the work, as well as the quality of the finished product.

 The presence of the above distinguishing features in comparison with the prototype allows us to conclude that the proposed technical solution meets the criterion of "novelty."

 An additional search for technical solutions, determined by these distinctive features, did not reveal their combined use in other areas of technology to achieve the goal, which allows us to conclude that the claimed technical solution meets the criterion of "inventive step".

 The drawing schematically shows an inertial separator, a longitudinal section. The inertial separator comprises a conical housing 1 with inlet and outlet nozzles 2 and 3, respectively, and located inside the storage bell 4 and the guide bell 5 with shutters 6 and 7, respectively. In the lower part of the housing 1, estruses 8 of the first return stage are provided, and the tapering part of the bell of the drive 4 is directed towards the inlet pipe 2 and is connected to the estrus 9 of the second return stage. The sockets 4 and 5 with the body 1 are fastened with the help of rods 10. The size of the annular channel between the indicated sockets, determined by the distance l between the edges of the socket, is fixed with the help of pins 11 fastening them.

 Inertial separator operates as follows.

 The flow of air mixture from the mill at high speed through the pipe 2 enters the separator and, by inertia, rushes into the annular channel between the pipes 4 and 5 with curvilinear generators. The cross-sectional area of the annular channel increases with increasing radii of the ring, and the flow rate of the air mixture decreases inversely with the area of this cross-section. Due to the curvilinear shape of the forming sockets, the axial direction of flow at the inlet to the socket 5 smoothly passes into a radial at the exit of the annular channel. When the flow moves along a curved annular channel, particles of solid material are centrifugally pressed against the outer surface of the bell 4 and then slide along its surface until it exits. Thus, at the exit from the annular channel, a two-layer flow with a small radial and zero axial velocity components is obtained.

где d_r диаметр частиц уносимой тонкой пыли;
d_m диаметр частиц, удовлетворяющих условию витания;
W скорость потока воздуха в кольцевом сечении между кромками раструба 5 и корпусом сепаратора 1 (соответствует скорости витания частиц с диаметром d_m);
ρ_в плотность воздуха;
ρ_m плотность размалываемого материала.In this case, the flow of a higher concentration of solid particles is at the top, and a low concentration of fine dust is at the bottom. After the flows exit from the edges 6 of the bell 4, a slightly dusty stream of fine dust from below rises upward and passes through the stream of solid particles and removes only those particles from it whose sizes satisfy the aerodynamic condition of particle flapping:

where d _{r the} diameter of the particles carried away fine dust;
d _{m is the} diameter of the particles satisfying the condition of soaring;
W is the air flow rate in the annular section between the edges of the socket 5 and the casing of the separator 1 (corresponds to the velocity of particles with a diameter of d _m );
ρ _in air density;
ρ _{m is the} density of the milled material.

This boundary condition provides a clear classification of the mill product by particle size. Then particles with a diameter of d _r <d _m are taken out of the separator in the form of finished dust, and particles with a diameter of d _r ≥ d _m fall out of the air stream and flow back to the domok 8. Large solid particles randomly introduced by the air flow into the upper part of the separator 1 fall into the socket 4 and return to the mill along the estrus 9.

The fineness of the finished dust is controlled by changing the air velocity in the annular section AA between the edges 6 and the separator body 1. When changing the height of the sockets 4 and 5 using the rods 10, the edges 6 approach or move away from the conical surface of the housing 1. At the same time, the area changes annular cross-section A-A and inversely proportional to it changes the air flow rate, which is the speed of soaring W for particles with a diameter of d _m .

где d₁ диаметр раструба в максимальном сечении по кромкам;
d₂ внутренний диаметр цилиндрической части корпуса сепаратора.The velocity of the mixture flow at the exit of the annular channel is determined by the distance l between the edges of the sockets 4 and 5. Based on the condition of equality of the velocities at the exit of the said annular channel and the annular section between the edges 6 of the socket 4 and the conical part of the separator body 1, the specified distance is determined from the expression:

where d _{1 the} diameter of the socket in the maximum section at the edges;
d _{2 the} inner diameter of the cylindrical part of the separator housing.

 To adjust the dust fineness, edges 6 and 7 are also used. In this case, the more the edges are downward deflected, the more large particles return to the dominant and the finer the finished dust.

 The proposed inertial separator when working in a dust system with an anti-jet mill can reduce energy consumption by 75 80 for transporting the mill product and dust.

Claims (5)

 1. Inertial separator of bulk materials, comprising a housing with inlet pipes located on the same vertical axis in the lower part and output in the upper part, provided in the lower part of the estrus body of the first return stage and installed in the housing along the specified axis of the drive in the form of a bell, the tapering part of which facing the inlet pipe and connected to at least one estrus of the second return stage, characterized in that it further comprises a guide bell mounted coaxially with a drive bell with the formation of a fixed annular inertial channel between their walls, and the diameter of the narrow end of the guide bell exceeds the diameter of the output end of the inlet pipe.  2. The separator according to claim 1, characterized in that the generatrix of the surface of each of the sockets is a smooth arc with a smoothly varying curvature. 3. The separator according to paragraphs. 1 and 2, characterized in that the distance between the edges of two adjacent sockets is determined from the expression

where d _{1 the} diameter of the socket of the drive in the maximum section at the edges;
d ₂ inner diameter of the cylindrical part of the separator housing.  4. The separator according to paragraphs. 1 and 3, characterized in that the edges of the sockets are provided with sashes.  5. The separator according to paragraphs. 1 to 4, characterized in that the sockets are attached to the upper part of the housing using at least three rods with adjustable length.