GAS CLEANING APPARATUS AND MORE PARTICULARLY TO AN IMPROVED ELECTRICAL ...

3,492,790

Patented Feb. 3, 1970

3,492,790

GAS CLEANING APPARATUS AND MORE PARTICULARLY TO AN IMPROVED ELECTRICAL PRECIPITATOR

Paul Ebert, Haut-Rhin, France, assignor to Societe Anonyme Aeropur A.G., Zug, Switzerland

Continuation-in-part of application Ser. No. 471,559, July 13,1965. This application Mar. 20,1968, Ser. No. 714,469

Claims priority, application France, Mar. 22, 1967, 99 893

Int. CI. B03c 3/41, 3134, 3/01 U.S. CI. 55—118 1 Claim

ABSTRACT OF THE DISCLOSURE

An apparatus for purifying gases and cleaning polluted air by means of water spray and ionization in a cleaning chamber whereby the impurities are deposited on a decanting surface and rinsed away. The specific improvements involved are: (a) rotating a shaft on which electrodes are mounted, in an insulated support which is mounted in a cell separate and sealed from the cleaning chamber, (b) providing a volute shaped inlet for the gases, so that it is more effectively distributed in the cleaning chamber by means of the swirling effect thus provided, (c) adding an internal sleeve constituting additional decanting surfaces in the cleaning chamber open to the inlet so that the swirling gas is distributed both around and within the sleeve, thereby providing additional capacity without additional size, (d) distributing spray nozzles within the chamber in a helical formation and directing the spray for a helical direction thereby adding the swirling and movement of gases more effectively through the chamber, and (e) improved configuration of the rotating electrode carrying members for more complete as well as adjustable ionization in the chamber.

ing nozzles and points. As for the decanting surfaces, they are subjected to a trickling action for the evacuation of the deposits of impurities that accumulate thereon. My copending application for a Precipitator, Ser. No. g 471,5,59 is an example of such devices.

SUMMARY OF THE INVENTION

The present invention provides improvements in the aforementioned installations which are directed in par

10 ticular to the separation of the insulating base of the shaft carrying the propellers and turnstiles from the chamber where the cleansing takes place.

Furthermore, there is provided a device through which is obtained an augmentation of the decanting surfaces

15 without causing any enlargement of the equipment, by imparting a rotative swirling motion to the gases to be evacuated, and subjected to an artificial draft, and at the same time assuring their prior washing while avoiding the fouling of the decanting surfaces. This rotative swirl

20 ing of the gases is obtained by means of a passage in the form of a volute, and by judiciously distributing spray nozzles which, at the end of a washing, further favor this mixing of the gases to be evacuated. The invention likewise extends to a special arrange

25 ment of the turnstiles and propellers equipped with points that are mounted hanging free in the evacuation passages on an insulated support located outside of the summit. The insulators of these supports are likewise mounted exteriorly to the evacuation conduits. This arrangement

30 permits grouping several evacuation conduits together with a common insulated support carrying the freemounted spindles, the supplying of the whole with highvoltage current being assured by a single common cable.

This is a continuation-in-part of my copending application Ser. No. 471,559, dated July 13, 1965, now U.S. Patent No. 3,443,362.

BACKGROUND OF THE INVENTION

The present invention relates to improvements in devices and processes for implementing the process by ionization whose function consists in purifying the gases emanating from smoke passageways or chimneys, and also applicable to ventilation and foul-air-cleaning systems or installations. According to this process, there are provided turnstiles or propellers (referred to generally as turnstiles) connected to a high voltage generator. From these turnstiles and propellers ions escape, enlivened under the effect of the accelerated movement of rotation, and which bombard the gases on their passage and favor, by the stirring thus obtained, the decanting or removal of the impurities.

Several devices directed to this object are already known; recourse has also been had, for accelerating the rotation of the turnstiles or propellers carrying the electrodes or points to blowing the compressed gases enclosed in the hollow of the shaft on which these members are mounted.

In addition, it has been proposed to make these turnstiles in a doughnut-like form provided with electrodes and flanked at the ends by hollow cross members carry

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BRIEF DESCRIPTION OF THE DRAWINGS

FIGURES 1 to 6 relate to two forms of construction directed to the amplification of the decanting surfaces, as well as to a pneumatic propulsion of the electrode-bearing shaft; and

40 FIGURES 7 to 9 relate to another form of construction including electrode carrying free-mounted spindles. More particularly:

FIGURE 1 shows an elevation in section of an evacuation chimney with amplified decanting surfaces in com45 bination with a volute passage;

FIGURE 2 relates to this volute in a cross-section view along the line 2—2;

FIGURE 3 relates to another form of construction of an evacuation chimney; 50 FIGURE 4 is a transverse section thereof along line 4—4;

FIGURE 5 is a transverse section along the line 5—5; FIGURE 6 shows the schematic of a turnstile carrying shaft driven by means of compressed air; 55 FIGURE 7 shows in profile and in vertical section, the arrangement of the top mounted shaft;

FIGURE 8 shows the combination of the two evacuation conduits of the FIG. 1; and

FIGURE 9 represents a plan view of this twin instal00 lation.

DESCRIPTION OF THE PREFERRED
EMBODIMENT

sleeves 78 and 79 of variable length. The gases, a according to the arrow are obliged to flow along these walls 78 and 79 through two annular axial flow channels defined by the first sleeve 79 and the second sleeve 78 and by the second sleeve 78 and the chimney 77, respectively. The gases are prevented from escaping through the center by the first sleeve 79. Spray nozzles 80 are located preferably in a helical arrangement, on the shields 77 and 78 to spray fluid into the flow channels tangentially to the walls 77 and 78, with the possibility also of a flow of water 81 from pipes 82, as in my prior application.

The introduction of the gases a into the chimney takes place through an inlet 83 developing into a volute 84 (FIGURE 2), likewise provided with spray nozzles 80 acting in the form of a fan in such a way as to produce, from the start, a vigorous swirling movement. The first sleeve 79 extends into the volute 84 to define its inner wall. The spray nozzles 80 spray fluid into the flow channels in the direction of swirl imparted to the gases by the volute 84 to increase the swirling motion and to precleanse the gases. I thus succeed in increasing the draft and accelerating the scrubbing of the gases, while increasing the feed and the yield without any enlarging of the installation being necessary.

The electrode turnstiles 85 and 86, whether they are fixed or rotative, are located in such a way that the gases to be cleansed, on coming out of the volute 84 through the two flow channels are ionized and impurities are collected in a conventional manner on the walls 77 and 78, respectively, from whence the impurities are decanted by the trickling water 81 along the shields 77 and 78 before the gases escape into the middle of the evacuation chimney.

With respect to the electrode turnstiles 85 and 86, there is advantage, for the purpose of regulating the appropriate distance from the decanting screens 77 and 78, in articulating them in such a way as to be able to move them and contract them, and bring them for example into the positions 85' and 86'. This regulation may take place, either by means of centrifugal force through a reduction or an increase of their movement of rotation or mechanically by the movement of articulation collars, or even by an oleo-pneumatic control.

The arrangement of FIGURE 3 differs from that of FIGURE 1 especially with respect to the form of the rotative electrodes. One of these is comprised of a hollow drum 87 equipped with points in combination with vaned wheels 88 likewise equipped with points mounted above and below the drum 87 (FIG. 4). The other electrode 89 includes straight blades 90 alternating with curved blades 91, both equipped with points. The drum 87 which may be in the shape of a truncated cone, or cylindrical, has the mission of driving the gases coming from the entrance 92 and directing them against the decanting screens 77 and 78, and the vaned wheels 88 have the effect of accelerating this projection.

The flow 81 emanating from pipes 82 takes place as before but without nozzles. The arrows at a indicate the direction of the movement of the gases to be cleansed.

In the precited two forms of construction, the insulated base 114 of the shaft 115 carrying the turnstiles and propellers 85 and 86 or 87, 88 and 89 is completely separated from the chamber where the cleansing takes place. In the form shown in FIGURE 1, a separate cell 116 is defined by a wall 117. In FIGURE 3 the flow from the washing device 82 is confined by the concentric sleeve construction to provide the separate location for the insulator 114.

When compressed air is utilized for the propulsion of the shaft 115 carrying the turnstiles 93 (FIGURE 6), this shaft includes a fixed tube 94 mounted on the insulating base 95 at the top of which is located the pneumatic motor 96, fed by the flexible conduit 97 coming from an appropriate compressor not shown. By the intermediary

of ball bearings 98 a second tube 99 carrying the turnstiles 93 covers the first and is driven by the motor 96 through a cap 100 which engages a tenon 101 projecting from the motor 96. This arrangement permits modifying the speed of rotation at will by varying the pressure. Furthermore, the addition of oil to the compressed air assures good lubrication and the ball bearings 98 are thereby protected against excessive stresses and are appropriately cooled.

In the form of construction of FIGURES 7 to 9, different from those previously described (FIGURES 1 and 3), the shafts .109 carrying the turnstiles or propellers 110 are suspended from a superstructure 107 and 112 provided exteriorly to the output end of the conduit. This arrangement permits grouping several evacuation conduits 102 supplied with high voltage current over a single cable.

The evacuation conduit 102 (FIGURE 7) consists of a cylindrical or truncated-cone-shaped shaft into which opens the entrance 103 of the gases to be purified along the line of the arrow a. This shaft includes on its walls the installation of a flow of water 104 with a collector 105 and a check point 106, and is surmounted by a support 107 on insulators 108. On the support .107 is suspended the downward hanging spindle 109 carrying the turnstiles or propellers 110 equipped with points. The downwardly suspended spindle 109 may be solid or hollow, fixed or rotatable, but it should not be able to oscillate. The supply of high voltage current is assured by the cable 111. This arrangement permits the grouping of several conduits 102. The FIGURES 8 and 9 show the combination of two of these units. The entrance conduit 103 for the gases to be treated may, in this case, be branched at 113 (FIGURE 9) towards the different units of the treatment apparatus 102. A single cable 111 suffices to supply the whole simultaneously with high voltage current.

Instead of the trickling with water or other appropriate liquid, the cleaning of the decanting screens may be performed dry by providing, according to the case, a vibrating device, tremblers, beaters or scrapers. I claim:

1. An electrical precipitator for the purification of gases comprising:

a chimney defining a cleaning chamber;
a volute-shaped inlet disposed at one axial end of said
chamber for driving said gas into said chamber in
a swirling motion;
a first sleeve internally concentric with said chamber
and extending axially into and defining the inner
wall of said volute;
a second sleeve internally concentric with said cham-
ber disposed intermediate said first sleeve and said
chimney and extending axially to the exit of said
volute entrance, thereby providing said cleaning
chamber with two annular axial flow channels for
said swirling gas, the first said channel being de-
fined by said chimney and said second sleeve and
the second said channel being defined by said second
sleeve and said first sleeve;
a carrying shaft disposed axially within said first sleeve;
an insulated support positioned outside of said clean-
ing chamber channels for supporting said carrying
shaft;

two electrode turnstiles having points connected to a
high voltage source mounted for rotation on said
carrying shaft, the first said turnstile being posi-
tioned to ionize gas passing through said chan-
nel and the second said turnstile being positioned
to ionize gas passing through said second channel,
said points being mounted on radially adjustable
vanes;

a plurality of spray nozzles disposed around the inner walls of said chimney and said second sleeve adapt75 ed to spray fluid essentially tangential to said walls

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