US 3501898 A
Description (OCR text may contain errors)
March 24, 1970 B. LINDHOLM ETAL 3,
EMITTING ELECTRODE ASSEMBLY FOR ELECTROSTATIC PRECIPITATORS Filed March 5, 1966 Z -Z/ 2 gijimw/ United States Patent 3,501,898 EMITTING ELECTRODE ASSEMBLY FOR ELECTROSTATIC PRECIPITATORS Bengt Lindholm and Giista Mildh, Vaxjo, Sweden, assignors to Aktiebolaget Svenska Flaktfabriken, Stockholm, Sweden Filed Mar. 3, 1966, Ser. No. 531,612 Claims priority, application Sweden, Mar. 5, 1965, 2,850/65 Int. Cl. B03c 3/40 US. Cl. 55147 3 Claims ABSTRACT OF THE DISCLOSURE A mounting for the emitting electrode of an electrostatic precipitator which permits easy mounting and dismounting including a mounting plate connected to a frame of the precipitator and having at least one aperture for receiving the electrode. The electrode is provided with an anchoring plug adapted to engage in the aperture. Either the plug or the aperture is tapered so that there is a line contact between the plug and the aperture.
The present invention relates to an emitting electrostatic precipitator comprising a rectangular frame and a plurality of resilient electrodes clamped in the frame between two opposite sides thereof.
Electrostatic precipitators of this type require that the fastening between the frame and the electrodes be as rigid as possible. It must also allow easy mounting of the electrodes and permit easy dismounting of individual electrodes, for example, when exchanging electrodes. Conventional types of exchangeable electrodes are not entirely satisfactory since the contact pressure between the electrodes and the frame is insufficient, which results in considerable current peaks. The current peaks produce flashovers which, under certain physical conditions, destroy the electrodes by corrosion.
The present invention has as its primary object to produce a stable emitting electrode assembly which eliminates the disadvantages of the prior conventional devices. The
invention is characterized in that two of the side members of the frame are provided with the necessary number of electrode holders, each of which comprises a mounting plate parallel to the side member. The plate has at least a first aperture for the application of the electrode either in the form of a slotted opening extending from one of thefree edges of the plate or in the form of a key-holeshaped opening, and at least a second aperture adapted to receive anchoring elements, afiixed to the electrodes. The anchoring elements abut within the second aperture with a line contact between the element and the aperture so that the anchoring elements, due to the resilience of the electrode, are caused to press against the mounting plate only along the common abutment line.
The preferred embodiment of the invention permits simple and easy mounting and dismounting respectively, and in addition, includes the advantage that contact pressure of suflicient strength is maintained, even when the anchoring elements and holders are exposed during operation to corrosion and erosion.
A suitable embodiment of the invention is characterized in that both the first and the second apertures are integral parts of a single slot or opening. The second apertures may also be made as separate elements and be symmetrically disposed on both sides of the first aperture.
If the mounting plate of the electrode holder is provided with a single hole, the anchoring element on the electrode suitably consists of a body or plug having a bore or passage which is threaded over the end of the electrode. The anchoring element in such cases may be "ice secured to the electrode by a welded or soldered fused metallic joint applied at the outwardly facing end of the element. To reduce or prevent bending stress which may arise when the electrode is being connected to the anchoring element, the bore passage in the anchoring element is preferably flared, or formed with a rounded, slightly conical inlet, at the inwardly facing end of the element.
If the mounting plate of the electrode holder is provided with a plurality of second apertures, the anchoring elements or plugs may alternatively be mounted on a plate which is secured to the electrode.
The invention will now be more fully described hereinafter with reference to the accompanying drawing wherein:
FIG. 1 is a fragmentary side view of an emitting elec trode assembly in accordance with the invention showing a single electrode and mounting plate;
FIG. 2is a sectional view taken on the line 2-2 of FIG. 1;
FIGS. 3a, 3b, and 3c are transverse sectional views showing alternative embodiments of the anchoring elements and support plate;
FIG. 4 is a view similar to FIG. 1 showing a modified embodiment of the present invention; and
FIG. 5 is a sectional view taken on the line 55 of FIG. 4.
Referring now to the drawing, a side piece 1 of the frame of the emitting electrode assembly has an electrode holder 2 secured thereto. The holder 2 has a mounting plate 2a parallel with the side piece 1 and terminating at its free edge in a slightly upwardly bent edge 2b. As shown in FIG. 2, a slot or first aperture 3 extends from one of the free edges of the plate 2a, in this case the far edge, and terminates in a hole or second aperture 4.
To facilitate transport and storage, the electrode may preferably be designed in the form of a tightly wound coil made of resilient material, as appears from Swedish Patent No. 152,406. An electrode of this type assumes a slightly wave shape when extended between the fastening points as it is clamped. The hole or second aperture 4 is intended to receive an anchoring element or plug 6 mounted at the end of the electrode.
In accordance with one feature of the invention, the contact between the anchoring element 6 and the hole 4 is a line contact. As shown in FIG. 3a, the anchoring element 6 is conical, tapering downward, and the second aperture 4 is cylindrical so that the tapering element 6 abuts the upper edge of the hole 4 with a line Contact. A reversal of parts is shown in FIG. 3b. In this embodiment of the invention, the hole 4b is conical tapering downwardly, and the anchoring element 6b is cylindrical. In this embodiment, the lower edge of the cylindrical element abuts the tapering wall of the hole in a line contact. The anchoring element may also be formed spherically, as shown in FIG. 30. In this embodiment, a spherical ball 60 engages a conical hole 4c, tapering downwardly, with a line contact between the ball and the hole at the point of tangency.
In each of the embodiments described above, the anchoring element is provided with a bore or passage for threading the electrodes therethrough as indicated at 7 in FIG. 3a. The lower end of the passages are flared to provide a rounded, slightly conical inlet at the inwardly facing end of the element, as indicated at 7a in FIG. 3a at 7b in FIG. 3b and at 70 in FIG. 30. The element is rigidly anchored in the bore or passage by a welded or soldered fused metallic joint applied at the outwardly facing end of the element, as indicated at 8 in FIGS. 1 and 3a, at 8b in FIG. 3b, at 8c in FIG. 30.
A further embodiment of an electrode holder is illustrated in FIGS. 4 and 5. In this embodiment of the invention, the side piece 1d of the frame consists of a pair of spaced bars, and a mounting plate 9 spans between the bars. The plate 9 is provided with a first aperture in the form of an elongated slot 10 extending parallel to the bars 1d from a free edge of the plate and communieating with a pair of second apertures or holes 11. Anchoring elements 12 in the form of downwardly tapering plugs are arranged on a common plate 13 which is secured to the electrode d by means of a welded or soldered fused metallic connection 80!. The anchoring elements 12 are arranged symmetrically in relation to the electrode 5a and the slot is provided with a widened portion 14 equally spaced between the second apertures 11 to prevent direct contact between the electrode 5d and the plate 9. Due to the symmetric suspension of the electrode 5d, possible movements of the electrode will not be transferred to the anchoring elements.
1. An emitting electrode assembly for electrostatic precipitators, comprising a rectangular frame including at least one set of two spaced-apart side members opposite to one another, and a given number of resilient electrodes comprising a group of electrodes stretched in the frame between the side members in said set, at least one of said side members being provided with a number of electrode holders corresponding to said given number, each holding mounting one electrode of said group in operating position, each of said electrodes being provided at least at said one end with an anchoring member secured to its associated electrode holder, said anchoring member comprising a plate rigidly connected perpendicularly to the electrode and provided with at least two spaced-apart contact elements, each of said electrode holders comprising a mounting plate parallel to its associated side member, said mounting plate having at least one free edge, aperture means including a slot extending from said free edge inwardly to a point in alignment with said operating position for receiving the electrode, and at least two spacedapart holes in said aperture means each receiving one of said contact elements of the associated anchoring member, said holes and said contact elements being so formed with respect to each other that said contact elements, due to the resilience of the stretched electrode, press against the mounting plate with a wedged line contact.
2. An emitting electrode assembly according to claim 1 wherein said slot intersects with said holes.
3. An assembly according to claim 1 wherein said contact elements are disposed symmetrically on opposite sides of said electrode.
References Cited UNITED STATES PATENTS 1,572,347 2/1926 Beck. 2,708,488 5/1955 Larsson 151 2,708,980 5/1955 Hull 55147 X 2,867,286 1/ 1959 Streuber 28720.5 X 2,870,861 1/1959 Valvo et al. 55147 X 2,874,802 2/1959 Gustafsson et al. 55l0 3,027,970 4/1962 Mueller 55148 X FOREIGN PATENTS 980,435 12/1950 France.
503,495 7/ 1930 Germany.
517,262 2/1931 Germany. 1,016,905 l/1966 Great Britain.
HARRY B. THORNTON, Primary Examiner D. E. TALBERT, 111., Assistant Examiner US. Cl. X.R.