JP2009006220A - Scale suppressing electrolysis unit and scale suppressing electrode pair for flowing water electrolyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable the prevention of scale adhesion with a foaming action on a cathode surface by reducing the area of a cathode in an electrolysis unit for a flowing water electrolyzer. <P>SOLUTION: The electrolysis unit is structured so as to perform electrolysis in a tubular member for water passing, containing a cathode and an anode. The tubular member is divided into a plurality of canalicular electrolysis elements 4. Each electrolysis element 4 is formed as a couple of an electrode pair by inserting a rod cathode 8 into a cylindrical anode 6, and in such a structure, scale adhesion onto the cathode surface 20 is inhibited by a foaming action on the cathode surface 20 on the outer periphery of the rod cathode 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a scale-suppressing electrolysis unit and a scale-suppressing electrode pair for a flowing water electrolysis apparatus. More specifically, the present invention relates to an electrolysis unit and an electrode pair in which, for example, the hot spring water is sterilized, and scale is difficult to adhere when electrolyzing electrolyzed water containing hardness components and metal ions. .

  When electrolysis is performed in electrolyzed water containing hardness components such as calcium ions and magnesium ions and metal ions, scales of calcium carbonate, magnesium carbonate, or metal oxide are deposited on the cathode surface, and the electrode surface is covered with the scale. Electrolysis efficiency may drop over time.

    In order to prevent this, in this type of electrolysis apparatus, two electrode plates for anode and cathode are inserted into the electrolysis tank, and both electrodes are used to prevent adhesion of metal ions to the electrode surface. There is known an electrolyzed water generating apparatus configured to reverse + and − of an electrode during energization of the electrode (Patent Document 1).

Similarly, as a flowing water type electrolyzer, a tube wall of a tubular member 100 that also serves as a water passage is used as a first electrode 102 as shown in FIG. 10, and carbon is coaxially formed through three support pieces 106 in the tube wall. It is known that the second electrode 104, which is a rod, is supported and electrolysis is performed between the first and second electrodes (Patent Document 2).
JP 2000-189971 Japanese Patent No. 3370735

    When the reverse operation for inverting the electrode as in Patent Document 1 is performed, the electrode surface is easily peeled off when the electrode is switched, and thus there is a problem that the life of the electrode is shortened.

    Although the electrolysis current is proportional to the electrode area, if the anode and cathode are simply opposed within the range of the electrolytic cell volume, the electrode area becomes limited, and gas (such as chlorine) is generated on the target anode surface. ineffective. In order to improve this point, there has been proposed an arrangement in which the second electrode is arranged on the cylindrical axis of the cylindrical first electrode as in Patent Document 2, but it still cannot be said that the electrode efficiency is sufficiently high. It was.

  The first object of the present invention is to prevent the adhesion of scale by the foaming action on the cathode surface by reducing the area of the cathode.

  The second object of the present invention is to improve the generation efficiency and make the apparatus compact by increasing the electrode area of the anode per unit volume.

The first means is an electrolysis unit for a flowing water type electrolyzer configured to perform electrolysis in a water passage tubular member including a cathode and an anode,
The tubular member is divided into a plurality of thin tubular electrolytic elements 4, and each electrolytic element 4 is used as a pair of electrodes, and one rod-like cathode 8 is coaxially inserted into one cylindrical anode 6. By forming
The foaming action on the cathode surface 20 on the outer periphery of the rod-like cathode 8 is configured to suppress the adhesion of scale to the cathode surface.

  In this means, the water-permeable tubular member is subdivided into a plurality of electrolytic elements that are electrode pairs, so that the anode surface per unit volume (the inner circumference of the tubular anode is compared with that of a single tubular tubular member. The total area (ΣSa) of the surface of the cathode is increased, and the area Sc of the cathode surface of each cathode is decreased, thereby preventing the scale from adhering to the cathode surface.

For example, it is assumed that there is an electrode pair having a length L composed of a cylindrical anode having an inner diameter R and a rod-shaped cathode having an outer diameter r (= aR). The area of the anode surface of the electrode pair is Sa = 2πRL, and the volume between both electrodes is V = π (1-a ² ) R ² L. Therefore, the anode area per unit volume is Sa / V = 2 / (1-a ² ) R. Instead of this electrode pair, if the inner diameter of the cylindrical anode is R → R / n, the outer diameter of the rod-shaped cathode is r → r / n (where n is an integer of 2 or more), and the length is the same, a new The anode area of the electrode pair (electrolytic element) is 1 / n times, and the interelectrode volume is 1 / n ² times. Therefore, the anode area per unit volume is n times. If n ² electrolytic elements are prepared to make the flow rate of electrolyzed water equal to one tubular member, the anode area becomes n times, so the amount of target gas (such as chlorine) generated from the anode surface is reduced. Will increase.

  Further, when the outer diameter of the rod-like cathode is reduced, the cathode surface which is the outer peripheral surface of the cathode is also reduced. Gas is also generated from the cathode surface by electrolysis, but the location where the bubbles are generated becomes narrow, so that the electrolytic product is less likely to adhere to the cathode surface, and scale adhesion is suppressed (scale). Since the cathode area that is the basis of growth is small, the generated scale is difficult to stay on the electrode surface, and therefore the scale is difficult to grow). Note that reducing the outer diameter of the cathode acts in the direction of decreasing the electrolysis current, such as increasing the electrical resistance of the cathode, but at the same time, the distance between the cathode and the anode is also reduced. Acts in the direction of increasing current. Since both actions cancel each other, an appropriate amount of current can be obtained even if the outer diameter of the cathode is considerably reduced.

  The “electrolytic element” is a unit of equipment having an electrolysis function, and includes a cylindrical anode, a rod-shaped cathode, and main members. In addition to these members, the electrolysis element includes a terminal for energization attached to the anode and the cathode, respectively, and a support means such as a spacer for appropriately maintaining the gap between the anode surface and the cathode surface. Can do. Each electrolytic element is preferably formed to have the same length. Each electrolytic element may be a member independent of each other, but may have a structure in which a plurality of holes are formed in a disk or square electrode material, for example. That is, the requirement to divide the tubular member means to divide the tube hole that is the electrolysis area.

      In this means, at least the ratio (ΣSc / ΣSa) of the total area ΣSc of the cathode surface to the total area ΣSa of the anode surface may be made smaller than the area ratio between the anode surface and the cathode surface of the tubular member. The area ratio between the anode surface and cathode surface of each electrolytic element may be the same as (a) the area ratio of the original tubular member, (b) may be set smaller than this, (c) depending on the case May be set larger than this. In the above description, (a) has been described as an example for the sake of simplicity, but (b) has a large effect of suppressing the adhesion of scale. This will be described later. However, (c) is also possible in design.

The second means includes the first means, and in a state where the cylindrical anode outer peripheral surfaces of the adjacent electrolytic elements 4 are in contact with each other, these electrolytic elements are bundled so that all the cylindrical anodes 6 are outer peripheral surfaces. It is in a state where it can be energized through.

  In this means, when the connection terminals are attached to one cylindrical anode by bringing the outer peripheral surfaces of the cylindrical anodes into contact with each other, all the cylindrical anodes can be energized through contact points on the outer peripheral surface. For that purpose, it is desirable to make all the cylindrical anodes into a straight cylindrical shape. Further, in a preferred illustrated example, three or more electrolytic elements are bundled in a dense state so that each electrolytic element is in contact with two or more electrolytic elements. As a means for binding, the periphery of the bundle of electrolytic elements may be covered with a binding material (resin tape or the like). It is convenient in terms of maintenance if the binding material is detachably attached around the bundle, and if one of the electrolytic elements becomes clogged, the electrolytic material can be separated by peeling the binding material.

The third means inserts the rod-like cathode 8 along the cylinder axis of the tubular anode 6, and forms the anode surface 18 formed by the inner peripheral surface of the tubular anode 6 and the cathode surface formed by the outer peripheral surface of the rod-shaped cathode 8. 20 and a scale-preventing type electrode pair that is a circumferential surface centered on the cylinder axis O,
The distance L between the anode surface 18 and the cathode surface 20 is constant over the circumferential direction, and is not changed in the longitudinal direction.
Furthermore, bubbles are generated on the cathode surface 20, and the area ratio of the cathode surface 20 to the anode surface 18 is made small to such an extent that the foaming action can suppress the adhesion of the scale to the cathode surface.

  In this means, an electrode pair suitable as an electrolysis element which is a part of the electrolysis unit of the first means or as an electrode for a single electrolysis apparatus is proposed. Therefore, the area of the cathode surface relative to the anode surface is reduced. The area ratio Sc / Sa is preferably in the order of a fraction to a few tenths. More specifically, it is set according to the concentration of impurities (cations such as calcium ions and magnesium ions) that cause scale in the electrolyzed water.

  In this means, the distance between the anode surface and the cathode surface is constant over the circumferential direction of the cylindrical anode, and is also constant with respect to the longitudinal direction. This is because if there is a variation in the distance between the poles, there will be places where the amount of energization is locally large and small, and the degree of scale adhesion may vary. In the preferred illustrated example described later, the anode surface and the cathode surface are large and small when viewed from the cross-sectional direction, but any shape can be used as long as the distance between the electrodes is constant, for example, large and small ellipses similar to each other. It may be a shape. In addition, separation means (such as a spacer) for making the distance between the electrodes in the longitudinal direction constant may be provided at an appropriate position of the electrode pair. The distance between the electrodes can be, for example, about 1 cm.

According to the 1st means, there exist the following effects.
O By reducing the area ratio of the cathode surface 20 to the anode surface 18, the current density at the cathode surface can be increased, and the generation of hydrogen from the vicinity of this surface can be promoted to suppress the adhesion of scale.
○ Since there is no need for reverse operation, electrode deterioration can be prevented.
O Since the cylindrical anode and the rod-shaped cathode are combined, the electrode area per unit volume is increased compared to the case where two types of electrode plates are simply opposed, and the gas generation efficiency at the anode is increased.

  According to the second aspect of the invention, since the connection terminal for the anode can be a single terminal, the structure is simple and the handling is easy.

  According to the third aspect of the invention, scale adhesion can be suppressed as a part of the above-described electrolysis unit or as a single electrode pair for the electrolyzer, so that maintenance is easy.

  1 to 6 show an electrolysis unit 2 according to an embodiment of the present invention.

  The electrolysis unit 2 includes a plurality of electrolysis elements 4, a binding material 12, and electrical terminals 14 and 16.

  Each electrolytic element 4 is formed by a cylindrical anode 6, a rod-like cathode 8, and a separating means 10.

  The cylindrical anode 6 is formed in a straight cylindrical shape having a circular cross section, and the rod-shaped cathode 8 is formed in a circular rod shape. These electrodes can be formed of platinum-plated titanium, iridium oxide-plated titanium, carbon or the like.

  As shown in FIG. 3, the spacing means 10 is inserted between the cylindrical anode and the rod-shaped cathode as a spacer for maintaining a constant distance L between the cylindrical anode 6 and the rod-shaped cathode 8. This spacer is fitted to the outer peripheral surface of the rod-like cathode 8, has protrusions protruding in the radial direction at three or more locations in the circumferential direction, and the tip of the protrusion is in contact with the inner surface of the cylindrical anode 6. A gap for the liquid to flow is formed between these protrusions. Two or more such spacers may be attached in the longitudinal direction of the electrolytic element.

  These electrolytic elements are combined into one bundle, and a binding material 12 is wound around and bonded to the outer peripheral surface of the bundle. The cylindrical anode of each electrolytic element is in contact via the outer peripheral surface, and at least one anode terminal 14 for the cylindrical anode is provided. Each rod-like cathode 8 is provided with a cathode terminal 16.

  In the above configuration, when energized between both terminals, bubbles are generated around the cathode surface as shown in FIGS. The generation of bubbles prevents the electrolytic product causing the scale from adhering to the cathode surface 20. On the other hand, since the pole area per unit volume is large on the anode surface 18, an object such as chlorine is sufficiently generated. In FIGS. 5 and 6, the structure of the spacer is omitted for explanation.

  FIGS. 7A and 7B are examples in which several cylindrical anodes 6 are bundled in a polygonal cylinder having a round hole. When the outer surface is uneven as shown in FIG. 5B, a case having a shape corresponding to the binding material can be used.

  FIGS. 8A and 8B are examples in which the peripheral walls of the cylindrical anode of each electrolytic element are combined. In other words, a large number of holes may be passed through one plate-like electrode member, and a rod-shaped cathode may be inserted into each hole.

  FIG. 9 shows an embodiment of the flowing water type electrolysis apparatus 30. This apparatus expands the diameter of a part of a circulation path 32 for taking water from a bathtub 46 in a hot spring area, and the electrolytic unit 2 of the present invention is built in the expanded diameter portion 34, and hot water sterilized by electrolysis is stored in the bathtub. It is configured to return. 36 is a valve, 38 is an external power source, 40 is a water supply pump, and 42 is a vent hole.

It is a cross-sectional view of the scale inhibition type electrolysis unit according to the present invention. It is a longitudinal cross-sectional view of the electrolysis unit of FIG. It is a cross-sectional view of the principal part (electrolytic element) of the electrolysis unit of FIG. It is a longitudinal cross-sectional view of the principal part of FIG. It is a cross-sectional view which shows the action state of the principal part of FIG. It is a longitudinal cross-sectional view which shows the action state of FIG. 2 is one example of the electrolysis unit of FIG. 1. It is another one Example of the electrolysis unit of FIG. It is the Example which applied the electrolysis unit of FIG. 1 to the flowing water type electrolysis apparatus. It is a partial cross section figure of the conventional flowing water type electrolysis apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Electrolytic unit 4 ... Electrolytic element 6 ... Cylindrical anode 8 ... Rod-shaped cathode 10 ... Separation means 12 ... Bundling material 14 ... Terminal for anode 16 ... Terminal for cathode 18 ... Anode surface 20 ... Cathode surface 30 ... Flowing water type electrolysis apparatus 32 ... Circulation path 34 ... Diameter expansion part 36 ... Valve 38 ... External power supply 40 ... Water supply pump 42 ... Gas vent hole

Claims (3)

An electrolysis unit for a flowing water type electrolysis apparatus configured to perform electrolysis in a tubular member for water passage including a cathode and an anode,
The tubular member is divided into a plurality of thin tubular electrolytic elements 4, and each electrolytic element 4 is used as a pair of electrodes, and one rod-like cathode 8 is coaxially inserted into one cylindrical anode 6. By forming
A scale-inhibiting electrolytic unit for a flowing water type electrolyzer configured to suppress adhesion of scale to the cathode surface by a foaming action on the cathode surface 20 on the outer periphery of the rod-shaped cathode 8.   In a state in which the cylindrical anode outer peripheral surfaces of adjacent electrolytic elements 4 are in contact with each other, these electrolytic elements are bundled so that all the cylindrical anodes 6 can be energized through the outer peripheral surface. A scale-suppressing electrolysis unit for a flowing water type electrolyzer according to claim 1. The rod-shaped cathode 8 is inserted along the tube axis of the tubular anode 6, and the anode surface 18 formed on the inner peripheral surface of the tube-shaped anode 6 and the cathode surface 20 formed on the outer peripheral surface of the rod-shaped cathode 8 are both formed into a tube. In the anti-scale type electrode pair that is a circumferential surface centered on the axis O,
The distance L between the anode surface 18 and the cathode surface 20 is constant over the circumferential direction, and is not changed in the longitudinal direction.
Further, the scale is characterized in that bubbles are formed on the cathode surface 20 and the area ratio of the cathode surface 20 to the anode surface 18 is reduced to such an extent that the foaming action can suppress the adhesion of the scale to the cathode surface. Suppressive electrode pair.

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