GB2131330A

GB2131330A - Electrostatic dust separator

Info

Publication number: GB2131330A
Application number: GB08331843A
Authority: GB
Inventors: Wilfred Schnabel; Ehreshover Strasse Ber Colombo
Original assignee: Kloeckner Humboldt Deutz AG
Current assignee: Kloeckner Humboldt Deutz AG
Priority date: 1982-12-01
Filing date: 1983-11-29
Publication date: 1984-06-20
Also published as: BR8306502A; DK547583D0; DK547583A; JPS59109258A; FR2537015A1; DE3244397A1; ES527645A0; ES8406899A1; GB8331843D0

Abstract

In an electrostatic dust separator having a gas inlet 12 near the bottom and discharge and collecting electrodes 7, 4, dust discharge channels 9, 10 are provided, which fan out radially and downwardly below the electrodes, so that dust falling from the electrodes is directed towards the wall of the housing 2 away from the incoming upwardly flowing gas. The electrodes are provided with a mechanical or pneumatic device for cleaning off collected dust. <IMAGE>

Description

SPECIFICATION Dust separator The present invention relates to a dust separator and, in a preferred embodiment, more particularly to an electrostatic dust separator consisting of a housing extending verticually through which the gases flow from the bottom upwards, with discharge and collecting electrodes disposed therein, the collecting electrodes being of tubular construction and the discharge electrodes passing centrally through the tubular collecting electrodes, and devices being provided to clean off the dust deposited on the discharge and collecting electrodes.

A tubular electrostatic filter is known from the DE-OS 29 19989 wherein the tubular collecting electrodes are combined to form a plurality of units in the form of sets which rest on resilient cushions.

These tubular collecting electrodes are in communication with impact shaking-off devices by means of which the collecting electrodes are periodically set in vertical oscillation when the electrostatic filter is in operation. The dust shaken off the collecting electrodes in this manner falls down, counter to the flow of gas, onto a saddle-shaped bottom of the electrostatic filter from where it is taken off into a central funnel by means of worm conveyors. Between the lower end of the tubular collecting electrodes and the crude gas supply there is a screen grid equipped with spiral inserts which is intended to act as a gas-accumulating and gas-distributing medium.

Since, in this case, the dust shaken off the collecting electrodes has to be taken counter to the stream of gas, through the openings of the screen grid, down onto the bottom of the filter, it is impossible to prevent some of the dust which has already been shaken offthecollecting electrodes from being entrained upwards again by the stream of gas which impairs the efficiency of dust separation in the electrical field of the dust separator. Also gas eddies may form on the screen grid and lead to an accumulation of relatively large amounts of dust between the screen grid and the collecting electrodes, which amounts of dust can no longer be handled by the electrostatic filter.

The present invention seeks to provide a dust separator in which one or more of the abovementioned disadvantages are overcome or reduced.

According to the present invention there is provided a dust separator consisting of a housing through which gases flow from the bottom upwards and having dust collecting members disposed therein, wherein dust discharge channels are provided below the dust collecting members, the dust discharge members fanning out downwardly from a central region of the housing.

As a result of the arrangement of dust discharge channels below the collecting members, e.g. electrodes, there is achieved in an advantageous manner a uniform distribution of the stream of crude gas over the whole cross-section of the filtering arrangement without disadvantageous eddy formation occurring. Furthermore the dust shaken offthe collecting members and falling down into the dust discharge channels is not brought into contact with the stream of gas again, as a result of which accumulations of dust or circulations of dust in the separating compartments are reliably avoided.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 shows a longitudinal section through an electrostatic dust separator with a mechanical clean ing device; and Figure 2 shows a partial longitudinal section on a larger scale through a collecting electrode of tubular construction with a pneumatic cleaning device.

The electrostatic dust separator illustrated in Fi gure 1 consists of a cylindrical upper housing portion 1 and a funnel-shaped bottom portion 2. Inn the upper region of the upper housing portion 1, tubular collecting electrodes 4 are loosely sus pended on a supporting structure 3. In the lower region of the upper housing portion 1, the tubular collecting electrodes 4 are guided, with slight play, in a guide plate 5. Acting on this guide plate 5 is a mechanical cleaning device 6 which is disposed externally on the filter housing and which periodical ly sets the collecting electrodes 4 in horizontal oscillation.As a result of the periodic impact im pulses transmitted from the mechanical cleaning device 6, via the guide plate 5 to the collecting electrodes 4, the tubular collecting electrodes 4 are so strongly vibrated horizontally as a result of their slight play in the guide plate 5, that as a result, the dust deposited on the collecting electrodes is detached and discharged from the collecting electrodes towards the bottom.

Passed centrally through the tubular collecting electrodes 4 are discharge electrodes 7, which are suspended on a carrier 8 which is in operational communication with a knocking device, not illustrated in the drawing, in order to clean off the dust.

Provided below the discharge and collecting electrodes 4 and 7 are dust discharge channels 9 and 10 which are disposed one above the other with spacing in the funnel-shaped bottom portion 2 and which are disposed fanning out centrally from the inside of the housing extending conically radially outwards towards the wall 2 of the housing bottom.

The arrangement of the dust discharge channels 9 and 10 is such that the upper dust discharge channels 10 cover the gap between the two dust discharge channels 9 below them in each case, so that no dust can fall through downwards between the dust discharge channels 9 and 10. The dust falling down into the channels 9 and 10 during the periodic cleaning of the discharge and collecting electrodes 4 and 7 is drawn off very advantageously towards the funnel-shaped wall 2 of the bottom, without coming into contact in this region with the dust-laden gases introduced through the pipeline 12 below the dust discharge channels 9 and 10. The separating zone provided with the discharge and collectiong electrodes 4 and 7 is therefore very advantageously protected from disadvantageous dust loading and as a result a very high effectiveness of dust removal is ensured.In addition, as a result of the arrangement of the dust discharge channels 9 and 10 below the discharge and collecting electrodes 4 and 7, a uniform distribution of the dust-laden gases over the whole cross-section of the dust separator is also very advantageously achieved and renders possible a uniform loading, on all sides, of the discharge and collecting electrodes 4 and 7 disposed in the electrostatic dust separator. The dust separated out of the gases in the dust separator is removed continuously or periodically downwards out of the bottom portion 2 in the direction of the arrow 13 and the gases freed of dust are withdrawn from the dust separator upwards in the direction of the arrow 14.

As Figure 2 shows, the tubular collecting electrodes 15 of the electrostatic dust separator can also be very advantageously provided with a pneumatic cleaning device. For this purpose, the tubular collecting electrodes 15 are connected, in a gas-tight manner, to two cover plates 16 and 17 disposed one above the other with spacing, in the upper region. The tubes 15 are provided, in the region between the plates 16 and 17, with a plurality of slits 18 which are disposed distributed in the form of a ring in the tube wall and which are directed obliquely downwards towards the middle of the tube. Air, stream or another inert gas is periodically blown, at an elevated pressure, for example at 10 atmospheres into these slits 18 from the outside via the space 19 between the cover plates 16 and 17, in the direction of the arrows 20 and as a result the dust adhering to the innerwall of the tubular collecting electrodes 15 is detached. An effective cleaning of the discharge and collecting electrodes of an electrostatic dust separator can also be achieved very advantageously in this manner.

Claims

1. A dust separator consisting of a housing through which gases flow from the bottom upwards and having dust collecting members disposed therein, wherein dust discharge channels are provided below the dust collecting members, the dust discharge members fanning outdownwardly from a central region of the housing.

2. A dust separator according to claim 1, wherein the dust discharge channels extend almost to the wall of the housing.

3. A dust separator according to claim 1, wherein the dust discharge channels are substantially conical.

4. A dust separator according to any preceding claim, wherein gas introducing means are provided below the dust discharge channels at a central region of the housing.

5. A dust separator according to any preceding claim, wherein means are provided for cleaning dust off the dust collecting members.

6. A dust separator according to claim 5, wherein the cleaning means comprise a mechanical cleaning device.

7. A dust separator according to claim 5, wherein the cleaning means comprise a pneumatic cleaning device.

8. A dust separator as claimed in any preceding claim, wherein the housing has a generally cylindrical upper portion and a bottom portion which tapers downwardly, the dust discharge channels being located in the bottom portion.

9. An electrostatic dust separator according to any preceding claim, wherein the dust collecting members comprise discharge and collecting electrodes.

10. An electrostatic dust separator according to claim 9, wherein the collecting electrodes are tubular and the discharge electrodes pass generally entrally through the collecting electrodes.

11. A dust separator substantially as herein de scribedwith reference to Figure 1,orto Figure 1 as modified by Figure 2, of the accompanying drawings.