JPS6129783B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge electrode member for an electrostatic precipitator, the electrode member comprising a tube, the tube having a rigid structure for dispersing and discharging ions by means of projections integral with the tube. It relates to a discharge electrode member that constitutes a structure.

In electrostatic precipitation, suspended dust particles or dispersed fluid are separated by charging the dust particles and forcing them under the action of an electric field to a collecting electrode that is grounded or at another potential. is removed from the gas stream.

To protect the environment against unwanted dust, industrial electrostatic precipitators are used to remove solid particles such as fly ash, mineral dust, cement dust, etc. from gases before they are released into the atmosphere. Widely used.

Electrostatic precipitators are already well known and are known to use discharge electrodes in the form of wires, rods, bars or tubes mounted in rows in a frame between plate-like collecting electrodes. There is.

Furthermore, discharge electrodes are known which have a tubular support and whose discharge arms are divided into pointed discharge tips. Such discharge electrodes are mechanically stable and can reach substantial heights without causing problems, such as lateral vibrations caused by distortion of the support frame when handling hot gases. Can be effectively used in certain electrostatic precipitators. However, such discharge electrodes have the disadvantage that the distribution of the electric field exposes the discharge chips to highly concentrated charges and their discharge, thereby increasing the risk of flashovers. These discharge chips are also exposed to corrosion due to electrostatic corrosion, which often results in burnout of the discharge chips.

It is therefore an object of the present invention to provide an improved discharge electrode of the type consisting of a tubular structure.

According to the invention, this improvement is achieved by designing the discharge electrode to have a projection that is integral with the tube, the projecting end of which has a rounded surface.

By designing the protrusion in this manner, it is possible to obtain a preferably balanced ion emission distribution from substantially all end faces of the protrusion. The risk of arc formation is thus avoided to a considerable extent.
Furthermore, the rounded surface is not significantly exposed to galvanic corrosion and the projections are mechanically very stable.

The discharge electrode according to the present invention has a uniform distribution of ionization and an electric field of sufficient level to achieve the most efficient dust collection.
Suitable for use in large scale industrial electrostatic precipitators.

The protrusions are rod-shaped but can take various forms, either as a single rod integral with the tube or as a continuous wire attached to the tube and bent to form a rod-like protrusion. attached to the tube structure.

In a preferred embodiment of the invention, one or more continuous wires are embedded in a recess in the surface of the tube, and the two branches are preferably joined to create a crease in the wire and the free ends thereof By constructing the rod as having a rounded surface, the folded portion of the wire is projected to form a protrusion.

The recesses may be parallel to the generatrix of the tube, may be helical, or may be concentric. The protrusions are protruded by a distance corresponding to 1/10 of the diameter of the tube to the diameter of the tube, and have an interval corresponding to the degree of protrusion of the protrusions up to 20 times that amount.

In another suitable embodiment of the invention, the protrusion is made to project outwardly from the wall of the tube, and the protrusion has a rounded apex.

The projections forming part of the tube are preferably made in a continuous embossing process, which improves the strength of the electrode and increases its mechanical stability. The projections are rounded at their apex and thus retain their relative size and shape irrespective of possible corrosion or electrostatic corrosion.

In a preferred embodiment of the invention, the rounded apex has a minimum radius of curvature that is less than or equal to the total height of the protrusion.

This relationship between the curvature of the projection and the tube achieves an effective distribution of the dust-carrying and ionizing fields. Furthermore, the harmful effect of burning out the protrusions is avoided and the risk of flashover is largely eliminated.

In one form according to the invention, the rounded apex is substantially spherical.

In one embodiment of the invention, the tube consists of two or more pieces joined longitudinally.

The tube may thus be made on the basis of a metal band with embossed projections and flanged or welded in a continuous process. Such a bond improves the mechanical stability of the electrode.

The discharge electrode structure according to the invention is particularly suitable for electrostatic precipitators with unidirectional collection fields and pulsed ionization fields and with a simple and robust design.

Furthermore, the electrode design according to the present invention allows for a proper unidirectional potential of the tube to create a uniform electric field relative to the collector electrode, while a pulsed potential across the discharge and collector electrodes via the rounded surface of the projection. improves the function of the precipitator in that it creates a uniformly distributed ion cloud at certain intervals.

The tube may be angular and provided with projections on at least two of its edges. Such electrodes may be made on the basis of one piece, bent to the required shape and perhaps embossed, or by joining two or more pieces. and may be shaped to obtain a preferred distribution of dust transport and ionization fields.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Figures 1, 2, 3 and 4 of the attached drawings
9 to 14 show structural examples of discharge electrodes as a premise of the present invention or as an aid to the explanation of the present invention, and the structures of FIGS. 1, 2, 3 and 4 are shown. In the example, the tube 1 is provided with a rod-shaped projection 2 with a rounded end surface 3 or with a wire having turns 5 forming the projection, each projection having a rounded end surface 6. ing.

5, 6, 7 and 8 show an embodiment according to the invention, in which a modified tube structure 7 has a longitudinal recess 8 on its surface. Wires 9 or 10 are embedded in these recesses. The wire 9 is formed with inverted V-shaped wire fold projections 11 having rounded end faces 12, and the wire 10 has rod-shaped projections 13 which likewise have rounded end faces 14. We are prepared.

In the example shown in Figures 1 and 2, the single
The rod-like protrusion may be welded to the tubular structure or may be joined to the tubular structure in other well known manners. The surface of the tube structure itself is substantially smooth, and a uniform electric field is created around the tube structure when a voltage is applied to the electrodes, while the rounded ends of the rod-like protrusions A concentrated electric field is established. The ion cloud generated by this concentrated electric field is emitted in a dispersed manner, but arcing does not occur because the rounded surface spreads the discharge electrode.

Therefore, the charging of dust is significantly improved, and the efficiency of collecting solid particles is increased.

In the example construction shown in FIGS. 3 and 4, the protrusion is created by a wire 4 attached to the tube. This structure is very easy to manufacture and
The protrusions are interconnected with wires so that one protrusion cannot be accidentally knocked off or burned out. However, in this structure example, parts other than the protrusions of the wire also protrude from the surface of the tube, and this protruding part of the wire may cause unnecessary electrical discharge or dust may accumulate on that part. It turns out that there is.

Therefore, in the embodiments of the present invention shown in FIG. 5, FIG. 6, FIG. 7, and FIG. 8, the advantage of the structure example of FIG. 3 and FIG. In order to solve the above-mentioned problems of the structural examples shown in FIGS. 3 and 4 while maintaining the
is provided in the tube, with only the protrusion 11 protruding from the surface of the tube 7, and the other wire portions are buried in the recess 8. Therefore, the surface of the tube has projections 11
It is made to be substantially uniform except for the part. This consists of wires 9 or 10 along the surface of the tube.
to avoid causing uncontrolled discharge. Furthermore, the wires 9 or 10 prevent dust deposits on the electrodes, which could otherwise destroy the desired distribution of the electric field.

The form of the projections 11 or 13 depends on the preferred discharge from the electrode, the diameter of the wire 9 or 10, the spacing between the projections, their length, etc.

Figures 9 to 14 show electrodes in which the protrusions are embossed on the tube wall and are therefore integral with the tube.

The tube can have various cross-sections as shown and may be formed in one piece;
It may also be formed by longitudinally connecting or flanging multiple sections.

In the example structure shown in FIGS. 11 and 12, projections are provided in a plane that is parallel or perpendicular to the direction of the collecting electrode during use in order to obtain a favorable directional distribution of the ionizing field. Directed.

The electrode according to the invention is used in an electrostatic precipitator having a unidirectional electric field created by a unidirectional voltage and an ionizing field created by a pulsed voltage. Unidirectional voltages are typically less than the voltage limit that causes flash flash in the precipitator, while pulsed voltages are generally above this limit.

With the electrodes of the invention, the unidirectional electric field, which acts as a transport field for suspended particles or dispersed fluid, is uniformly distributed over the surface of the tube structure, while the ionizing electric field is directed outward from the protrusions. Therefore, the configuration of the protrusions determines the distribution of the ionizing electric field. The rounded configuration of the apex of the projections confines the ionization field so that the distribution of the ionization field emanates from a substantial portion of the surface of each projection and at the same time from a specific area of the discharge electrode.

The width of the pulse voltage is short enough to achieve effective charging of the dust particles while avoiding flashover.

When the electrostatic precipitator is of substantial height, mechanical vibrations in the long tube structure can be controlled by loading the tube. For example, this could be done by inserting a weight, perhaps in the form of a column of gravel, in a position within the tube such that this weight suppresses mechanical vibrations by absorbing their energy. achieved.

[Brief explanation of the drawing]

FIG. 1 is a side view of the first discharge electrode as a premise of the present invention or as an aid to the explanation of the present invention, and FIG. 2 is a side view of the first discharge electrode.
FIG. 3 is a side view of the second discharge electrode as a premise of the present invention or as an aid to the explanation of the present invention; FIG. 4 is a cross-sectional view taken along the line - in FIG. 5, 6, 7, and 8 are views showing embodiments of the discharge electrode according to the present invention, and FIG.
FIG.
Figure 0 is a sectional view taken along the - line in Figure 9,
The figure is a side view of an electrode having an elliptical tube as a premise of the present invention or as an auxiliary to the present invention, and Figure 12 is the same as Figure 11.
13 is a sectional view taken along the line XII-XII, FIG. 13 is a side view showing still another discharge electrode as a premise of the present invention or as an aid to the explanation of the present invention, and FIG. 14 is a -
It is a sectional view along a line. DESCRIPTION OF SYMBOLS 1...Pipe, 2...Protrusion, 3...Rounded end surface, 4...Wire, 5...Wound, 6...Rounded end surface, 7...Deformed tube structure, 8 …
...dented part, 9, 10... wire, 11, 13...
...Protrusion, 12, 14...Rounded end surface.

Claims (1)

[Claims] 1 A support tube having one or more recesses formed on its surface and a plurality of discharge protrusions, the protrusions being bent to provide each protrusion with a rounded tip surface. A discharge electrode for an electrostatic precipitator, characterized in that the wire is disposed within the recessed portion so that each of the protrusions extends to the outside of the tube.