US2050607A - Electrode for electrically heated steam boilers and the like - Google Patents

Description

N. HALLMAN Aug. 11, 1030.,

ELECTRODE FOR ELECTRICALLY HEATED STEAM BOILERS AND THE LIKE Filed Feb. 2, 1955 Patented Aug. 11 1936 UNITED STATES PATENT OFFICE] ELECTRODE FOR ELECTRICALLY HEATED STEAM BOILERS AND THE LIKE Application February 2, 1935, Serial No. 4,644 In Sweden February 10, 1934 2 Claims.

The present invention relates to electrically heated steam boilers and the like constructed with a substantially circular cross-section and provided with a plurality of current admission electrodes.

The main object of the invention is to provide for the greatest possible uniformity in respect of the distribution of the current density within the boiler when in use, so as thereby to secure the greatest possible distribution of the steam generation to the whole cross sectional area of the boiler, and a facilitated escape of the steam mainly formed in the proximity of the electrode rods.

In the art to which the invention relates it is known to construct the electrodes in the shape of a group of vertically extending rods arranged in a circle and supported by a common current admission member. It is also known to provide a plurality of electrodes each of which is triangular in shape and having outer faces concentric with the shell and inner faces parallel to each other.

The object of my invention is to provide a novel arrangement of electrodes having certain characteristic features of both these known constructions but embodying also other specific features, novel per se and in combination, whereby there are insured a more nearly uniform distribution of the current density and uniformity of the steam generation.

A preferable embodiment of the invention is illustrated in the accompanying drawing in which:-

Fig. 1 shows a steam boiler constructed according to the invention and provided with three current admission electrodes, seen in vertical section, and

Fig. 2 is a cross section of the boiler at the line AB in Fig. 1.

Referring to the drawing, 1 is the boiler shell which is closed at the upper end by a cover 2 supporting the electrodes. Each of the electrodes consists of a support plate 3 conductively connecting a plurality of substantially vertical electrode rods inclining downwardly at a small angle towards each other. In each electrode, these rods are positioned in an annular, or squirrel-cage, configuration, and the main characteristic of the invention is that the cross (horizontal) section of this configuration forms a circle sector, as will be seen from Fig. 2.

If the boiler is provided with three current admission electrodes, as shown in the drawing, the angle of each of the sectors will be about (Cl. 2l940) 129, and since all of the sectors, besides having an equal radius, have also the same centre coinciding with the longitudinal axis of the circular boiler shell, the arcs of the same will be concentrio with the said shell.

While still adhering to the same principle of construction it is naturally possible also to employ another number of electrode aggregates than that shown in the drawing for the sake of explanation.

In addition to the current admission electrodes described above, the boiler ought also to be provided with at least one current escape electrode, or zero voltage electrode, and this last mentioned electrode may consist of the boiler shell a manner known per se. In order to arrive at the greatest possible uniformity in respect of the distribution of the current density, and steam generation, this is not entirely sufiicient in all instances, however, when the current admission electrodes are constructed according to the invention. In such instances the preferred embodiment of the invention includes the provision of radial metal plates within the boiler between the separate current admission electrode aggregates 3, 4 such plates being, preferably, conductively connected with the boiler shell and serving to increase the area of the current escape, or zero voltage, electrode.

The boiler shown in the drawing may naturally be fed both with single-phase and three-phase alternating current, as all of the electrode aggregates 3, 4 may be connected with the same phase, or each of them with a separate phase, respectively.

In case the boiler is intended to be fed with three-phase alternating current, the plates 5 may be omitted so that a direct current transmission between the phases may be obtained at the substantially radially extending portions of the sector-shaped electrode aggregates.

What I claim and desire to secure by Letters Patent is:

1. In an electrically heated steam generation means of the character described and which comprises a boiler shell of a substantially circular cross-sectional shape and having a substantially vertical axis and a multiplicity of current admission electrode rods extending downward within the shell, the improvement which comprises such rods arranged in a uniformly distributed plurality of groups, the rods of each group being electrically connected with each other and arranged in three rows to form in horizontal cross-section the radii and are of a circle sector, the separate electrode of each group being positioned so to have a slight inclination toward each other in a downward direction so that the horizontal areas of sectors formed at difierent levels progressiveily decrease in a downward direction.

2. In an electrically heated steam generation means according to claim 1, the additional feature of current escape electrodes comprising vertically extending plates each positioned substantially radially of the shell and between and spaced from and approximately parallel to the rows of rod electrodes which in cross-section form adjacent radii of two adjacent sectors as specified.

NILS HALLMAN.

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