DE1135423B - Device for separating dust from a gas flow with a mechanical pre-separator and an electrostatic main separator - Google Patents

Description

The invention relates to a device for separating dust from a gas stream with an electrostatic precipitator, collecting elements between a main inlet and outlets has, over which a cleaning gas stream is passed. In a known embodiment is before the electrostatic separator is a mechanical pre-separator that removes the dust in such with fine and one with coarse grain size sifts and separates, with a gas line to the pre-separator which leads the fine dust to the main inlet of the electrostatic precipitator.

In this known system, all of the dust separated in the electrostatic precipitator is removed completely returned to the mechanical separator. The pre-separator also sorts the dust here only in fine and in coarse particles. The purge gas flow can also pass through a mechanical auxiliary separator be guided, who removes the fine dust from him, removed, whereupon it is fed back into the main gas flow before the mechanical pre-separator.

In such systems, the separation of the fine dust particles is not entirely satisfactory, so that there is a need for a more efficient and economical separation system. .

According to the invention, therefore, in addition to the mechanical pre-separator, such a device yet another mechanical auxiliary separator is provided, to which the line for the pre-separator the coarse dust particles and the discharge of the dust-laden cleaning gas from the electrostatic precipitator lead and from which the relatively dust-free gas through a discharge into the Line is discharged before or after the pre-separator.

Since the known device has only a single mechanical separator, this must be done accordingly the largest throughput. However, the invention allows through the arrangement of the mechanical auxiliary separator reduces the size of the two mechanical separators. A smaller mechanical separator works more efficiently and economically than a large one. Since a mixing chamber is arranged in front of the auxiliary separator, into which the Derivation for the coarse dust particles and, from the electrostatic precipitator, the derivation for the When the dust-laden cleaning gas flows in, the coarse dust becomes with the fine dust from the electrostatic Mixed separator; This also saves on the size of the fans and their drive. A bigger one This means that it is cost-effective.

Device for separating

of dust from a gas stream

with a mechanical pre-separator

and a main electrostatic precipitator

Applicant:

Apra Precipitator Corporation,
New York, NY (V. St. A.)

Representative: Dr.-Ing. E. Maier, patent attorney,
Munich 22, Widenmayerstr. 4th

Claimed priority:
Great Britain of December 27, 1956 (No. 39 279)

James Edmund Sayers, Bearsden, Dunbartonshire

(Great Britain),
has been named as the inventor

To further increase the economic efficiency of the dedusting system according to the invention, the In addition to separating into fine and coarse dust particles, pre-separators are also used to separate Medium-sized dust particles can be set up, and these can be a secondary electrostatic precipitator are supplied, from which a cleaning gas stream is fed to the auxiliary separator in addition to Flow of the coarse dust particles from the pre-separator and the cleaning flow from the electrostatic Main separator. In the drawing shows

1 shows a schematic view of a device for separating dust from a gas stream according to FIG the invention,

Fig. 2 is a schematic representation of another embodiment.

In the embodiment of the dust extraction system according to the invention described below the dust-laden gas flow 9 is the pre-separator 10, which is preferably a cyclone separator is supplied, which has its most favorable degree of separation in the area of coarse dust particles. Be in it practically all coarse particles are separated from the gas stream. These particles are out of the separator carried away by a small portion of the gas stream.

209 638/336

The small dust particles are practically not separated by this pre-separator 10, and the greater part of the gas, which still carries these fine particles with it, is fed via the line 11 to the main electrostatic separator 14 , in which the dust particles are precipitated. The main electrostatic precipitator 14 is preferably divided into two rows of electrodes, each of which can in turn be shut off from the main gas flow and is then exposed to a high-speed flow of flushing gas; by means of which the dust precipitated in the respective row during the previous working period is removed and discharged via a line 15. For this purge gas flow, a portion of the gas is preferably used which is branched off from the main gas flow either upstream or downstream of the main electrostatic separator.

The mechanical pre-separator 10 is with a further outlet in a zone for the separation of medium-sized particles from the dust-laden gas stream. These particles become via a line 13 through a small partial gas flow to an additional electrostatic secondary separator 16 supplied, in which these particles are deposited.

The additional electrostatic secondary separator 16 is of a similar construction to the electrostatic one Main separator 14, however, can because of the smaller volume of the gas passing through be smaller, with the precipitated · ■ dust, as described above, by a purge gas flow is removed via line 17. That which emerges from each of the electrostatic precipitators Purified gas is combined and discharged through a main gas outlet 18.

A purge fan 20 sucks the purge gas flows from the lines 15, 17 from both electrostatic separators and conveys them to a mixing chamber 40 and then to the mechanical auxiliary separator 22. The gas flow 12 carrying the coarsest particles is also fed to the mixing chamber 40 at the auxiliary separator 22, in which essentially the entire residual dust is separated from the gas and then collected in a funnel 23 below the auxiliary separator. The mechanical auxiliary separator 22 is preferably a multi-cell deflector separator.

The gas cleaned in the auxiliary separator 22 is then returned to the main gas flow with the aid of a further blower 24 via a line 25 either upstream or downstream of the mechanical pre-separator 10. In most cases it is preferable to conduct this gas of the main gas flow between the pre-separator 10 and the main electrostatic separator 14, ie into the line 11 after the pre-separator 10.

In each of the lines carrying the purge gas flows and in the coarse dust gas flow to the mechanical Auxiliary separators 22 are expediently provided with throttle devices or control valves 26, 27, 28.

The dedusting system described has the advantage that by separating the main part of the dust particles from the main gas flow before it Entering the main electrostatic separator 14, only a small amount of dust is deposited in the latter needs to be, so that the power consumed to wash away this dust is less than with the previously known systems. Also for rinsing the additional electrostatic secondary separator 16 required power is small because it is small in size.

Another embodiment of the dedusting system is shown in FIG. The main separator A is a multicyclone in which the dust-laden gas is passed through a large number of cells and the coarse dust is separated by a vortex effect in each cell. A main gas flow 11 A still carrying fine dust particles is fed to the electrostatic separator 14 A , in which the fine dust is separated off. A small part of the gas carrying the coarse dust particles is fed via a line 13 A to a mixing chamber 40 A, which is arranged below the main separator 10A , and to a mechanical auxiliary separator 22 A, preferably a multi-cell deflector. A sucked through the duct by the blower 20A ISA purge gas stream is used to remove dust from the electrostatic precipitator 14 A and promotion of the same to the mixing chamber 4OA used.

The gas and dust, which are taken from the mixing chamber 40A, are then fed to the mechanical Hilfsabscheider 22 ^ 4, in which the dust separated from the gas and is collected in a hopper 23 A. The cleaned gas is returned to the main gas flow 9 A upstream of the pre-separator 10 Λ by a fan 24 A or can also be passed into the electrostatic separator 14 A.

Claims (3)

PATENT CLAIMS: 1. Device for separating dust from a gas flow with an electrostatic separator, which has collecting elements between a main inlet and outlets, an outlet on the electrostatic separator leading a cleaning gas flow over the collecting elements and a mechanical pre-separator which is arranged in front of the electrostatic separator, which collects the dust sifts and separates those with a fine and one with a coarse grain, and a gas line is connected to the mechanical pre-separator, which leads the fine dust to the main inlet of the electrostatic separator, characterized in that in addition to the mechanical pre-separator (10, 10 ^ 4) Another mechanical auxiliary separator (22, 22A) is available, to which the line for the coarse dust particles (12) from the pre-separator (10, 10 A ) and the discharge line (15) of the dust-laden cleaning gas lead from the electrostatic separator (14, 14A) , and from which the relatively dust-free gas d is discharged through a discharge line (25) into the line upstream or downstream of the mechanical pre-separator (10, 10A) . 2. Apparatus according to claim 1, characterized in that a mixing chamber (40, 40/4) is arranged in front of the mechanical auxiliary separator (22, 22A) , into which from the mechanical pre-separator (10, 10A) the discharge for the coarse dust particles ( 12, ISA) and from the electrostatic precipitator (14, 14 ^ 4) die The discharge line for the dust-laden cleaning gas (15/15/1) opens. 3. Apparatus according to claim 1 or 2, characterized in that the mechanical pre-separator (10) apart from fine and coarse dust particles also separates those of medium size and these are fed to an electrostatic secondary separator (16), from which a cleaning gas stream (17) the mechanical auxiliary separator (22) is fed in addition to the flow of coarse dust particles (12) from the mechanical Pre-separator (10) and the cleaning gas flow (15) from the main electrostatic separator (14). Considered publications:
German Patent No. 935 123;
German Auslegeschrift M 27360 VIIIc / 12e, (published on November 15, 1956. 1 sheet of drawings