United States Patent 3641302

An apparatus for heating liquids by high-frequency energy composed of an outer casing, an inner longitudinally disposed central electrode, and a cylinder separating the inner electrode from the outer casing thereby forming two concentric annular zones. The liquid flows first through the inner zone, and then through the outer zone in series.

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H05B6/62; (IPC1-7): H05B5/00; H05B9/06
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Primary Examiner:
Staubly R. F.
Assistant Examiner:
Jaeger, Hugh D.
What is claimed is

1. In an apparatus for treatment of liquid materials with high-frequency electrical energy, the combination of

2. In apparatus for treatment of liquid materials with high-frequency electrical energy, the combination of an electrode structure comprising

3. The combination defined in claim 2, wherein said means closing said outer zone is an annular end wall; said tube extends outwardly through said end wall; and liquid can be introduced directly into the extended end of said tube.

4. The combination defined in claim 2, wherein said discharge means defines a plurality of discharge openings spaced about said casing at least generally in the location of the end of said rod electrode remote from said disc.

5. The combination defined in claim 4, wherein said discharge means includes means defining two discharge openings which are diametrically opposed across said casing.

This invention relates to apparatus for treating liquids with high-frequency electrical energy, and more particularly to apparatus of the general type covered by my prior U.S. Pat. No. 3,060,297, issued Oct. 23, 1962, and No. 3,184,575, issued May 18, 1965.

In said prior patents I disclosed an electrode structure comprising a horizontally disposed cylindrical casing or shell of conducting material through which the liquid mixture is caused to circulate, a central electrode extending axially of this casing, and a high-frequency electrical generator having one terminal connected to said casing and the other terminal connected to said central electrode. This central electrode is supported at one end only by means of an insulating disc carried at the end of the casing, and is substantially shorter than the casing.

In the first of said patents the liquid is introduced into the casing at a point adjacent the end at which said central electrode is supported, and is discharged axially from the other end.

In the second patent, both ends of the casing are closed, and the liquid is introduced into that end of the casing remote from the supported end of the central electrode, and is discharged from the end adjacent the insulating supporting disc. This is what I have designated as the "reverse flow" arrangement of electrode structure.

In both of these prior designs the liquid passes only once through the annular space between the casing and the central electrode.

An object of the present invention is to devise an improved arrangement in which the liquid passes twice longitudinally through the space between the central electrode and outer casing, the two passes being in opposite directions. To this end I divide the said space into two concentric annular zones, and the liquid flows first through the inner zone and then through the outer zone in series, and is discharged from the same end of the electrode structure that it enters. Since the present invention somewhat resembles the above-mentioned "reverse flow" type, I have designated it as the "double pass reverse flow" arrangement.

In order that the invention may be readily understood, reference is had to the accompanying drawings, forming part of this specification, and in which:

FIG. 1 is a longitudinal section through my improved electrode structure;

FIG. 2 is a transverse section substantially on the line 2--2 of FIG. 1, looking in the direction of the arrows; and

FIG. 3 is a fragmentary longitudinal section, similar to FIG. 1, through one end of the electrode structure, showing a slightly modified construction.

Referring to the drawing in detail, and more particularly first to FIGS. 1 and 2, my improved electrode structure comprises an outer cylindrical casing or shell 1 of conducting material, having one end closed by a head or wall 2. At the opposite end is an insulating disc 3, secured by bolts 4 to a radial flange 1a of the casing and to a supporting wall 5 of a suitable housing. Extending axially of the casing 1 is an inner electrode 6, in the form of a rod, passing through the disc 3 and secured thereto as by means of a pair of clamping nuts 7 and 8, engaging threads on the end portion of the rod, the wall 5 having a relatively large opening 5a providing clearance for the rod. Thus, an open annular space is provided between the casing 1 and inner electrode 6, and this rod electrode is supported at one end only by the disc 3, the other end being free. The rod is substantially shorter than the casing, as shown in FIG. 1. Leads 9 and 10, extending from a high-frequency generator (not shown), are connected respectively with the inner electrode 6 and the casing 1, the latter being grounded. The lead 9, connected with the central electrode, preferably consists of a copper tube, water-cooled by means of hose connections 9a, as shown in FIG. 1 of said prior U.S. Pat. No. 3,184,575, the end of the tube being flattened, fitted over the threaded end of electrode 6, as at 9b, and secured by a nut 9c.

The construction and arrangement so far described are generally the same as shown in my said prior patents.

In the present invention, however, I divide the annular space between the outer casing and inner electrode into two concentric zones by means of a tube of insulating material 11, such as glass, which surrounds and is spaced from the free end portion of the electrode 6.

The end wall 2 is formed with a centrally located, axially projecting, threaded nipple 2a, through which the glass tube extends, and is sealed as by means of packing 12, compressed by means of a nut 13, threaded over the nipple 2a.

Liquid to be treated is introduced under pressure, by suitable piping (not shown) into the free end of the glass tube 11, in which it flows toward the left through the annular space between the tube and the electrode 6, emerging from the open left-hand end of the tube, and flowing thence toward the right, as indicated by the curved arrows, through the annular space between the tube 11 and the casing 1, until it reaches the discharge pipe or pipes. I have shown a pair of such discharge pipes 14, extending radially from the casing near the right-hand end thereof, at diametrically opposite points. Other arrangements of discharge pipe means may be employed.

The high-frequency electrical energy or field pervades and fills all of the space between the electrode 6 and casing 1, regardless of the presence of the insulating tube 11, and hence the liquid is subjected to the action of this energy once as it passes through the inner zone between the electrode and the glass tube, and again as it passes back through the outer zone between the glass tube and the casing. This "double pass" arrangement is much more efficient than the single pass arrangements of my prior patents.

The exact distance of the inner end of the tube 11 from the supporting disc 3 is not believed to be critical, so long as it affords ample free space to permit the liquid to reverse or change its direction of flow without undue friction.

While I have described the insulating tube as made of glass, it may also be made of suitable rigid plastic. This is illustrated in FIG. 3, where I have shown the end wall 2' of the casing 1' as formed integral therewith instead of being bolted on, and have shown the tube 11' as molded from plastic, having the necessary properties. This plastic tube is shown as having an annular rib or flange 15 formed integral therewith, against which flange bears the clamping nut 13'. In this figure I have also indicated how a threaded metal feed pipe can be connected to the lattice tube by screwing it into the same.