RU2174452C1 - Dust collector - Google Patents

Abstract

FIELD: cleaning gas flows from dispersed particles and dust. SUBSTANCE: dist collector has cylindrical housing with slotted nozzle mounted tangentially in its upper portion; this nozzle is intended for introducing contaminated gas over generatrices of inner surface of housing; shoulders are provided in way of inlet flow of contaminated gas; shell separating space at housing walls from central part is fitted coaxially in lower portion of housing. Space inside shell is communicated with vertical cylindrical chamber located above shell and then it is communicated with cleaned gas discharge unit through outlet branch pipe. Dust collecting bin is connected to lower portion of housing. EFFECT: simplified construction; ease in maintenance. 10 cl, 4 dwg

Description

 The invention relates to the separation of dispersed particles from gases or vapors using gravitational inertial or centrifugal forces by changing the direction of flow, in particular to devices for cleaning gas flows from dispersed particles and dust.

 Known devices for cleaning gases from dust. Common designs in which cleaning occurs through the use of inertial forces. The attractiveness of such devices lies in the fact that they are structurally simple, but the efficiency of dust cleaning in these devices is not always sufficient.

 Most often, dust collectors using inertial forces are carried out using a cyclone. As an example, the invention can be cited according to RF patents NN 2137528, 2116842, 2006291, UK application N 2284165. In cyclone dust collectors, dispersed particles fly under the influence of inertia and, meeting obstacles, such as cyclone walls, lose energy and are collected in dust collectors by gravity . Such dust collectors are good at catching large dispersed particles, but fine dust, which has a small mass, is usually carried away by the outgoing gas stream.

 The closest is the solution according to the patent of the Russian Federation N 2102115 "Jet-inertial dust collector", published. 01/20/98, IPC B 01 D 45/06. This dust collector contains a slotted nozzle for supplying contaminated gas, oriented downward tangentially to a curved surface, a deposition chamber and a guiding shield. The operation of the dust collector is based on the use of the Coanda effect. The gas flow changes its direction on a curved surface, and dust particles continue to fly under the influence of inertia into the dust bin. By means of a guiding shield, a secondary circulation flow is created in which additional dust deposition occurs.

 This dust collector allows you to clean the gas from coarse and medium-sized dust, fine dust is not captured enough. In addition, a dust collector of this design is difficult to manufacture.

 The present invention solves the technical problem of cleaning the gas stream from coarse and fine dust, combining the ease of manufacture and maintenance.

 The dust collector contains a cylindrical body, in the upper part of which a slotted nozzle for introducing contaminated gas is tangentially mounted. On the generators of the inner surface of the casing, in the direction of the input stream of contaminated gas, ledges are made. A shell is coaxially mounted in the lower part of the housing, separating the space at the walls of the housing from the central part. The space inside the shell is communicated with the cavity of the vertical cylindrical chamber located above the shell. The cavity of the vertical cylindrical chamber through the outlet pipe is in communication with the device for removing purified gas. A dust bin is attached to the bottom of the housing.

 The contaminated gas enters the housing through a slotted nozzle directed tangentially tangentially to the inner wall of the housing. On the path of a flat vertical gas flow ledges are made. A zone of reduced pressure arises behind each step, due to which the main flat vertical flow, according to the Coanda effect, deviates to the wall of the body, as if “sticks” to it. Behind each step, in the zone of low pressure, a vortex circulation flow arises. Thanks to this design, the flow of dusty gas is always located at the inner wall of the housing, making a spiral motion, dropping down the housing.

 During the movement of the polluted gas stream, coarse and medium-sized particles of pollution rub against the walls of the casing, lose mechanical energy and settle down, gathering in the dust collection bin.

 Fine dust particles are carried away in the circulation movement in the vacuum zones behind the ledges and gradually also descend along the generatrix of the housing behind the ledges and fall into the hopper.

 Thus, two processes are used in a dust collector for dust cleaning, one as in cyclones - loss of motion energy due to friction against walls for coarse and medium-sized particles, and the other for fine dust - deposition in circulation zones behind ledges.

 The shell divides the space inside the housing into the central part and the space near the walls of the housing. Dust settles near the walls of the casing, and a suction of purified gas is organized from the central part. In this case, the gas flow velocity in this zone is small, since the outlet pipe is connected to the lower central part of the housing inside the shell by a vertical cylindrical chamber having a diameter larger than that of the outlet pipe. Therefore, even small particles of dust are quietly deposited in the hopper, and the gas rises at low speed and only accelerates in the upper part of the vertical cylindrical chamber. The gas outlet stream is arranged by means of a gas exhaust device.

 This design effectively cleans contaminated gas from large and small particles of dust.

 In order for the gas input through the slot nozzle not to interfere with the circulation, it is better to place the slot nozzle for introducing contaminated gas in the wall behind the edge of one of the steps, and the step depth b can be made not less than the width S of the slot nozzle.

 From four to twelve ledges can be made on the inner surface of the housing.

 If the cross section of the wall behind the edge of the ledge has a semicircular profile, then the circulation flow behind the ledge will be more uniform, which improves the deposition of fine dust particles.

 For better adhesion of the gas stream to the wall behind the ledge and that the movement of the main stream is mainly laminar, the body segment from the recess of the ledge to the edge of the next ledge has a profile that is smooth in cross section.

 In particular, the distance f from the edge of the step to the outer wall of the vertical cylindrical chamber is related to the depth of the steps b by the ratio f ≥ 2b. In this case, the vertical flow does not touch the outer wall of the vertical cylindrical chamber and, therefore, unnecessary additional turbulence does not occur, worsening the gas purification process.

 For better gas cleaning, the distance L from the lower edge of the slot nozzle to the plane passing through the upper edge of the shell may be greater than or equal to 1 / 3h, where h is the height of the slot nozzle.

 In particular, in order for the purified gas flow at the bottom of the casing to move at a low speed and not to entrain precipitating fine dust particles behind itself, the ratio of the internal diameters of the outlet pipe and the vertical cylindrical chamber is 1: (3 - 5).

 A device for removing purified gas, in a particular case, can be made in the form of a suction fan.

 The invention is illustrated by drawings.

 In FIG. 1 shows the overall design of the dust collector in section.

 In FIG. 2 - section along AA in the diametrical plane.

 In FIG. 3 - a section along AA in the diametrical plane for a structure with a semicircular cross-sectional wall of the housing behind the ledge.

 In FIG. 4 shows a general view of the dust collector.

 The dust collector comprises a cylindrical housing 1 (Fig. 1). A slotted nozzle 2 for introducing contaminated gas is tangentially mounted in the upper part of the housing 1. On the generators of the inner surface of the housing 1, in the direction of the input stream of contaminated gas, ledges 3 are made (Fig. 1, 2). In the lower part of the housing 1, a shell 4 is coaxially mounted, separating the space at the walls of the housing 1 from the central part. The space inside the shell 4 is communicated with the cavity 6 of the vertical cylindrical chamber 5 located above the shell 4. The cavity 6 of the vertical cylindrical chamber 5 through the outlet pipe 7 is in communication with the device 8 for removal of purified gas (Fig. 4). To the lower part of the housing 1 is attached a hopper 9 for collecting dust (Fig. 1, 4).

 In special cases, the design of the dust collector is characterized by the following features and parameters.

 The slit nozzle 2 for introducing contaminated gas is located in the wall 10 behind the edge 11 of one of the ledges 3. The cross section of the wall 10 behind the edge 11 of the ledge 3 may have a semicircular profile (Fig. 3).

 The housing segment 12 from the recess of the ledge 3 to the edge of the next ledge 3 has a smooth cross-sectional profile. The distance f from the edge of the ledge 3 to the outer wall of the vertical cylindrical chamber 5 is connected with b by the depth of the ledges 3 by the ratio f ≥ 2b (Fig. 2) so that the flow does not touch the walls of the chamber 5.

 The distance L from the lower edge of the slotted nozzle 2 to the plane passing through the upper edge of the shell 4 (Fig. 1) should be chosen to be better than or equal to 1 / 3h to better clean the gas stream from fine dust, where h is the height of the slotted nozzle 2.

 The dust collector operates as follows.

 The gas flow with dust enters the housing 1 through the slotted nozzle 2. The slotted nozzle 2 forms a vertical flat stream that propagates along the wall of the housing 1. Encountering the ledges 3, the gas flow deviates to the wall of the housing 1, and behind the ledge 3 there is a low pressure zone, which in turn causes a circulation flow. Large and medium dust particles rub against the walls of the housing 1, lose energy and fall down the wall into the hopper 9 to collect dust. Small particles circulate in the area behind the ledge 3 and gradually lower also into the hopper 9.

 The gas flow in a spiral gradually moves down the housing 1. From the zone inside the shell, it is sucked up, entering first into the cavity 6 of the vertical cylindrical chamber 5, and then into the outlet pipe 7 under the action of the device 8 for removing the purified gas. The device 8 may be a fan or an ejector.

 Since the diameter d of the outlet pipe 7 is connected with the diameter D of the vertical cylindrical chamber 5 (Fig. 1) by the ratio 1: (3 - 5), the air flow inside the shell 4 and in the chamber 5 has a low speed and does not carry away dust particles.

 The design of the body and the main parts can be made of sheet material by welding.

 The dust collector is efficient in operation, practically maintenance-free and can be cleaned by running a gas stream with coarse particles into the dust collector.

Claims (10)

 1. A dust collector, characterized in that it contains a cylindrical body, in the upper part of which a slotted nozzle for introducing contaminated gas is tangentially mounted, and ledges are made along the generators of the inner surface of the body, in the direction of introducing the contaminated gas flow, a shell is coaxially mounted on the bottom of the body, separating the space at the walls of the housing from the central part, the space inside the shell is communicated with the cavity of the vertical cylindrical chamber located above the shell, and then through the outlet the tubes are communicated with a device for removing purified gas, and a dust collection bin is attached to the lower part of the housing.  2. The dust collector according to claim 1, characterized in that the step depth is made not less than the width of the slot nozzle.  3. The dust collector according to claim 1, characterized in that the slotted nozzle for introducing contaminated gas is located in the wall behind the edge of one of the ledges.  4. The dust collector according to claim 1, characterized in that from four to twelve steps are made on the inner surface of the housing.  5. The dust collector according to claim 1, characterized in that the cross-section of the wall behind the edge of the ledge has a semicircular profile.  6. The dust collector according to claim 1, characterized in that the housing segment from the recess of the ledge to the edge of the next ledge has a smooth profile in cross section.  7. The dust collector according to claim 1, characterized in that the distance f from the edge of the ledge to the outer wall of the vertical cylindrical chamber is associated with the depth of the ledges b by the ratio f ≥ 2b.  8. The dust collector according to claim 1, characterized in that the distance L from the lower edge of the slotted nozzle to the plane passing through the upper edge of the shell is greater than or equal to 1 / 3h, where h is the height of the slotted nozzle.  9. The dust collector according to claim 1, characterized in that the ratio of the inner diameters of the outlet pipe and the vertical cylindrical chamber is 1: (3 - 5).  10. The dust collector according to claim 1, characterized in that the device for removing gas is made in the form of a suction fan.

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