RU2159144C2 - Jet-type inertial dust collector - Google Patents

Abstract

FIELD: cleaning air from medium- and coarse-dispersed dust, for example dust of building material materials in aspiration systems of pneumatic transport. SUBSTANCE: dust collector has slotted nozzle located at angle relative to horizontal axis and used for supply of gas flow; this nozzle is oriented tangentially downward relative to convex curvilinear surface adjoining upper part of nozzle; dust collector includes also vertical wall of settling chamber; semicylindrical wall having slots in its lower portion adjoins this chamber. EFFECT: high efficiency of dust collection, up to 75-99% depending on dust characteristics. 1 dwg

Description

 The invention relates to techniques for cleaning gas from dry medium and coarse dust of building materials.

 Currently, inertial dust collectors have become widespread in the dry dust gas cleaning technique, the main disadvantages of which include high aerodynamic drag, difficulty in manufacturing, insufficient reliability in working with weakly sticking dusts and the associated low degree of gas dust cleaning.

 Known inertial apparatus of the precipitation system of the grinding plant (av. St. USSR N1400646, MKI B 01 D 45/04, 1988), which works as follows. The dust and gas flow passes through the inlet duct. Under the influence of inertial forces, its particles rush to the outer wall of the gas duct. Then they fall into the slots formed by vertical ribs, and with a small amount of gas cut off by a concave sheet, they are diverted through the distribution chamber to the deposition chamber. After this, the flow rushes upward towards the purified gas and through the opening in a round horizontal central gas duct is directed to a further gas purification system. The following features coincide with the essential features of the claimed invention: inlet duct, slots for removing particles due to inertial forces, a deposition chamber (hopper) and a discharge duct. The disadvantages of this apparatus include a relatively low degree of purification, since the separation of particles occurs only in the separation zone of the dust and gas stream. There is no circulation flow and secondary low-pulse jet, forming an additional stage of particle separation.

 As a prototype, a jet-inertial dust collector having the largest number of matching essential features was selected (patent RU 2102115, class B 01 D 45/06, 01/20/98). The dust collector operates as follows. Dusty gas enters the receiver and flows out of the nozzle. The gas flow “sticks” to the convex curved surface and propagates along it in the circumferential direction according to the Coanda effect. Under the action of centrifugal forces, dust particles fly out of the jet and fall into the deposition chamber. After separation from the curved surface, the stream propagates according to the laws of an ordinary flooded stream to a vertical wall at an arbitrary angle, while a stream line is established in the stream. Purified gas with a low dust concentration, located above this line, enters the device for removal of purified gas. A stream with a high concentration of dust spreads down from the dividing line along the surface of the vertical wall and part of the dust is removed from it through the slot. To create a circulation zone of the flow and to eliminate the breakthrough of this stream, a guide plate is installed on the wall on the wall, flowing down from which the dusty gas collides with the peripheral part of the main stream. In this case, a secondary low-pulse jet is formed, with which part of the contaminated stream leaves the deposition chamber and a significant amount of dust is carried out. As industrial tests have shown, the main drawback of this design is the deposition of dust on the shield, its gradual accumulation and subsequent termination of separation through the adjacent gap.

 The proposed jet-inertial dust collector is aimed at solving the problem of reducing aerodynamic drag and increasing the reliability of operation. The expected technical result in the implementation of the invention is to increase the degree of purification of gas from dust.

 The invention is illustrated in the drawing, which shows a longitudinal section of a dust collector.

 The positions in the drawing indicate: a gas flow receiving device 1, a slotted nozzle 2, a convex curved surface 3, a device for removing the purified gas 4, a dust collecting sedimentation chamber 5, a semi-cylindrical wall 6, slots 7, a flat wall 8, a dividing current line 9, a secondary low impulse jet 10, circulation current 11.

 The dust collector operates as follows. Dusty gas enters the device 1 and flows out of the slot nozzle 2. The gas stream adheres to the convex curved surface 3 and propagates in the circumferential direction according to the Coanda effect. Under the action of inertia forces, relatively large particles fly out of the jet and fall into the deposition chamber 5. After separation from the curved surface, the flow propagates according to the laws of an ordinary flooded turbulent jet. When the jet flows on the walls 6 and 8, a stream dividing line 9 is established in the stream. The gas located above this line enters the device for removing purified gas 4. A stream with a high concentration of dust flows downward from the dividing line along the half-cylindrical wall 6, forming a circulation flow 11. Under the influence of centrifugal and gravity particles are separated through slots 7 located in the lower part of the wall 6 and are removed into the deposition chamber 5. The radius of the semi-cylindrical wall 6 is selected so as to separate The continuous streamline 9 fell on the boundary of the plane 8 and semi-cylindrical 6 walls.

 When comparing the proposed device with the prototype, a clear analogy in the design. The following essential features coincide: a gas flow receiving device 1, a slotted nozzle 2, a convex curved surface 3, a device for removing purified gas 4, a trapped dust sedimentation chamber 5, a flat wall 8, a dividing stream line 9, a secondary low-pulse jet 10. Similar to the principle of action is the use of the Coanda effect.

 In this dust collector, unlike the prototype (patent RU 2102115, class B 01 D 45/06, 01/20/98), the vertical wall on which the stream flows is replaced by a flat 8 and a half-cylindrical 6. One slot formed by a vertical wall and shield in the prototype, replaced by several slots in the lower part of the semi-cylindrical wall. The slots 7 in the lower part of the semi-cylindrical wall 6 do not allow dust deposits on it, the dust is separated through the slots and enters the deposition chamber. The lower part of the semi-cylindrical wall 6 plays the role of a shield in the prototype. Draining from it, the dusty stream collides with the peripheral part of the jet emerging from the slotted nozzle 2 and forms a secondary low-pulse jet 10. In the proposed device, the aerodynamic drag decreases: by installing a semi-cylindrical wall, it is possible to avoid frontal leakage of the jet onto a flat wall 8 below the dividing streamline. Inertial inertial dust collector containing a slotted nozzle for supplying a gas stream located at an angle to the horizontal axis, oriented downward tangentially to a convex curved surface located adjacent to the upper part of the nozzle, a vertical wall of the deposition chamber located opposite the outlet section of the nozzle and semicylindrical adjacent to it from below a wall having gaps in the lower part provides the desired technical result.

 The degree of purification of the dust collector can be 75-99%, depending on the characteristics of the dust.

Claims (1)

 An inertial inertial dust collector containing a slotted nozzle for supplying a gas stream located at an angle to the horizontal axis, oriented downward tangentially to a convex curved surface located adjacent to the upper part of the nozzle, a vertical wall deposition chamber opposite the nozzle exit section, characterized in that a vertical wall at the bottom adjoins a semicylindrical wall having gaps in the lower part, with the possibility of forming a dividing stream line in the flow between these walls.