WATER-CIRCULATING STERILIZER

Abstract

The object of the invention is to provide a water-circulating sterilizer that uses no chlorine-base bactericidal agents, has no effect on the human body with no change of water quality, with no running cost and completely free from maintenance while effective sterilization is possible within shorter time.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects of the present invention will become readily apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 shows an embodiment of the water-circulating sterilizer according to the invention, where FIG. 1A is a vertical cross section; FIG. 1B is a cross section along the line A-A in FIG. 1A; FIG. 1C is a cross section along the line B-B in FIG. 1A; FIG. 1D is a cross section along the line C-C in FIG. 1A;

FIG. 2 is a perspective view of the test apparatus equipped with the water-circulating sterilizer according to the invention; and

FIG. 3 shows a schematic block diagram of installation of the water-circulating sterilizer according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

One embodiment of the water-circulating sterilizer will be described with reference to FIG. 1. Pipes 5, 6 are connected to a water inflow port and a water outflow port, respectively, of a cylinder 2 of the water-circulating sterilizer 1 made of a hardly corrodable material such as stainless steel with interposition of respective joints 3, 4. Three plates of a first alloy plate 10, a second alloy plate 11 and a third alloy plates 12 are combined into a set, and plurality sets of these first, second and third alloy plates 10, 11 and 12 are disposed in the cylinder 2 from the inflow port toward the outflow port of water (three sets in this embodiment).

The first alloy plate 10 comprises an alloy containing at least copper and tin. An alloy comprising five metals of nickel, zinc and iron in addition to copper and tin was used in this embodiment. The alloy is able to extract electrons from Legionella pneumophila by allowing the alloy to contain copper and tin.

The second alloy plate 11 comprises an alloy containing at least silicon and titanium. An alloy comprising six metals of nickel, zinc, copper and silver in addition to silicon and titanium was used in this embodiment. The alloy is able to electrically adsorb Legionella pneumophila by allowing the alloy to contain silicon and titanium.

The third alloy plate 12 comprises an alloy containing at least iron, molybdenum and manganese. An alloy comprising eight metals of nickel, zinc, copper, tin and aluminum in addition to iron, molybdenum and manganese was used in this embodiment. The alloy is able to charge Legionella pneumophila by allowing the alloy to contain molybdenum and manganese.

Each of the first, second and third alloy plates 10, 11 and 12 has a surface area from ¼ or more to ⅔ or less of the cross sectional area within the inner diameter of the cylinder 2. However, a surface area from ⅓ or more to ½ or less is preferable in terms of pressure loss. The first, second and third alloy plates 10, 11 and 12 are disposed by being shifted to one another so that water is able to easily contact the plates. While the first, second and third alloy plates 10, 11 and 12 are formed in a semi-circular shape in this embodiment, the shape is not particularly restricted and may be configured as perforated alloy disks.

The water-circulating sterilizer 1 configured as described above is used by being attached in a circulating flow passageway. When water flows in the water-circulating sterilizer 1, electrons of Legionella pneumophila in water are extracted with the first alloy plate 10 at first, the bacteria are electrically adsorbed on the second alloy plate 11, and the bacteria are charged on the third alloy plate 12. Viability of Legionella pneumophila declines by repeating the steps for contacting the first, second and third alloy plates 10, 11 and 12, and the bacteria finally become extinct. Although Legionella pneumophila survives after the bacteria passed through the water-circulating sterilizer 1 once, the bacteria are extinct while they circulate through the water-circulating sterilizer 1 plural times.

Effective sterilization in a shorter period than in the related art is possible with combined three alloy plates of the first, second and third alloy plates 10, 11 and 12 having different performances to one another, by repeating the steps of: extracting electrons from Legionella pneumophila at the first alloy plate 10; electrically adsorbing the bacteria on the second alloy plate 11; and charging the bacteria on the third alloy plate 12. Since the first, second and third alloy plates 10, 11 and 12 do not dissolve in water and are not ionized in water, the function of the water-circulating sterilizer 1 may be maintained for 20 years or more. The sterilizer neither affects the human body nor changes the quality of water since chlorine-base bactericidal agents are not used. There is no need of the running cost at all while the sterilizer is free from maintenance.

The results of bactericidal tests with the water-circulating sterilizer 1 will be then described. The test using the test apparatus shown in FIG. 2 was requested to Japan Food Research Laboratories. The water-circulating sterilized 1 was connected to pipelines 20 of the test apparatus. The pipeline 20 is a zinc-plated steel pipe with a diameter of 20 A and a length of 1845 mm. The capacity of the pump 21 used was 29 liters/min. Culture medium of Legionella pneumophila containing 2.8×10⁶ cells/m³ of the bacteria was filled in the circulating apparatus from the test solution inflow port 22 at the room temperature of 21 to 23° C., and the solution was allowed to continuously flow (circulate) for 48 hours at a flow rate of 1.5 m/sec with a pump 21.

The results shown in Table 1 were obtained by the test. Table 1 shows that almost all Legionella pneumophila at a concentration of 2.8×10⁶ cell/m³ at the start of the test was killed after 24 killed.

	TABLE 1
	Number of Legionella
	pneumophila in the
	test apparatus
Before circulation	2.8 × 106	cells/m3
1 hour after the start of circulation	2.8 × 105	cells/m3
6 hours after the start of circulation	1.6 × 103	cells/m3
24 hours after the start of circulation	10	cells/m3 or less
48 hours after the start of circulation	10	cells/m3 or less

FIG. 3 shows an example of installation of the water-circulating sterilizer of the invention. Warm water in a pool or bathtub 30 flows into a heat source 32 such as a boiler after removing impurities such as hairs, scales and dusts floating in water by a filter 31. Water heated with the heat source 32 is circulated with a pump 33 through the pool or bathtub 30 after passing through the water-circulating sterilizer 1. Effective sterilization of Legionella pneumophila as described above is possible by disposing the water-circulating sterilizer 1 in the circulating flow passageway. It is needless to say that the water-circulating sterilizer 1 according to the embodiment of the invention may be widely used in the circulating flow passageway of, for example, the hot spring and cooling tower other than the above-mentioned pool and bathtub 30.

It is readily apparent that the above-described embodiments have the advantage of wide commercial utility. It should be understood that the specific form of the invention hereinabove described is intended to be representative only, as certain modifications within the scope of these teachings will be apparent to those skilled in the art. Accordingly, reference should be made to the following claims in determining the full scope of the invention.

Claims

1. A water-circulating sterilizer disposed in a pipeline of circulating water for sterilizing Legionella pneumophila surviving in circulating water, wherein plural sets of a first, second and third alloy plates are sequentially disposed from a water inflow port,the first alloy plate comprising an alloy containing at least copper and tin,the second alloy plate comprising an alloy containing at least silicon and titanium, andthe third alloy plate comprising an alloy containing at least iron, molybdenum and manganese.

2. The water-circulating sterilizer according to claim 1, wherein the first alloy plate comprises an alloy of five metals of nickel, zinc and iron in addition to copper and tin, the second alloy plate comprises an alloy of six metals of nickel, zinc, copper and silver in addition to silicon and titanium, and the third alloy plate comprises an alloy of eight metals of nickel, zinc, copper, tin and aluminum in addition to iron, molybdenum and manganese.

3. The water-circulating sterilizer according to claim 1 or 2, wherein the first, second and third alloy plates are disposed so as to be shifted to one another in a cylinder, and these alloy plates has a surface area from ¼ or more to ⅔ or less of the cross sectional area within the inner diameter of the cylinder.