WO2006101290A1

WO2006101290A1 - Sensor for measuring chloride concentration, sensor for detecting microorganisms, and water purifying apparatus having the same

Info

Publication number: WO2006101290A1
Application number: PCT/KR2005/001776
Authority: WO
Inventors: Jong-Kwang Lee; Seok-Jae Lee; Moo-Hoon Kim; Yongho Yu; Doo-Hyun Park; Tae-Sik Hwang
Original assignee: Samsung Engineering Co., Ltd.
Priority date: 2005-03-22
Filing date: 2005-06-13
Publication date: 2006-09-28
Also published as: KR20060101973A

Abstract

A chloride concentration-measuring sensor includes a voltage-measuring unit, a reference electrode connected to a first end of the voltage-measuring unit, first and second switches connected to a second end of the voltage-measuring unit in parallel, first and second operational electrodes connected to the first and second switches, respectively, third and fourth switches connected to the first operational electrode in parallel, fifth and sixth switches connected to the second operational electrode in parallel, and a power supply unit having a first end to which the third and fifth switches are connected in parallel and a second end to which the fourth and sixth switches are connected in parallel, wherein a group of the second, third and sixth switches and a group of the first, fourth and fifth switches are alternately opened and closed.

Description

SENSOR FOR MEASURING CHLORIDE CONCENTRATION, SENSOR FOR DETECTING MICROORGANISMS, AND WATER

PURIFYING APPARATUS HAVING THE SAME

Technical Field

[1] The present invention relates to a sensor for measuring chloride concentration, a sensor for detecting microorganisms, and a water purifying apparatus having the same.

Background Art

[2] A variety of analyzing methods for measuring the amounts of a variety of chemical materials or biomaterials contained in an unknown sample have been developed. In recent years, an analyzing method that is very sensitive to a specific chemical material or biomaterial that is to be analyzed and is capable of obtaining an accurate analysis using a minimum amount of the sample.

[3] Particularly, with the need for quickly analyzing a sample for process automation and quality control for medical analysis and environmental sample analysis, a method and apparatus for effectively analyzing the chemical materials have been developed.

[4] The study of the relationship between a material and electrical properties such as potential difference, charge capacities, and conductivity is called electrochemistry. A method for chemically analyzing a material using the study is an electrochemical analyzing method. In potentiometry, a material is analyzed by measuring an electrode potential when no current flows. This can be done after an electrochemical cell is made by dipping a proper electrode into a liquid sample containing electrolyte. Con- ductometry is the measuring of conductivity between electrodes. Coulometry is the measuring of current flowing along an electrode. Amperometry is the analysis of a material by measuring the current flowing therethrough.

[5] In addition, there is a method for performing an analysis by simultaneously measuring two electrical properties. That is, a voltammetering is a technique of measuring the relationship between current and voltage. An example of a voltammetering is polarography. A voltammetry is an electrochemical analyzing methods in which information on a sample is obtained by measuring current variation according to the voltage applied between an operation electrode and a sub-electrode. The voltammetry was invented in the name of the polarography by a Czech chemist, Heyrovsky, in 1920s. As technology and apparatuses have been advanced, metal and organism concentrations of less than 0.5 mg/L can be measured through polarography.

[6] Meanwhile, as the standard of living rises, clean water quality is required for households to be used as drinking water and cleaning water. In response to this re- quirement, a variety of water purifying appliances such as water purifiers, water softeners, humidifiers, and bidets have been widely used. The water used for the water purifying appliances needs to have a quality higher than a predetermined level so that superior water can be obtained through the water purifying appliances.

[7] Generally, tap water is passed through the water purifying appliances. Before being supplied to the home, the tap water goes through a series of purifying processes such as a disinfectant adding process, a filtering process and the like in a water cleaning center. Diseases spread by water containing a large amount of microorganisms may be serious health threats, and thus, the concentration of the microorganisms in the water must be less than a predetermined level. Thus, chloride has been added as the disinfectant to eliminate the microorganisms in the water-cleaning center. The added chloride is generally removed by evaporation into the air during the purifying process or the supplying process to the home. However, some of the added chloride remains in the water. When the concentration of the remaining chloride is higher than a predetermined level, it may be a serious health threat.

[8] The water purifying appliances such as water purifiers, water softeners, humidifiers, and bidets function to reduce the concentrations of the microorganisms and the chloride to allowable levels. However, extended use of a filter deteriorates the performance of the filter, thereby making it impossible to effectively filter the microorganisms and the chloride. Therefore, there is a need for a sensor or another apparatus that can measure the microorganism concentration and the chloride concentration in the purified water.

[9] Methods or apparatuses for measuring microorganism and chloride concentrations contained in water has been developed. For example, there is a stabilized neutral or- thotolidine (SNORT) method utilizing a reagent such as

N,N-diethyl-p-phenylenediamine. However, the SNORT method has a problem in that it is difficult to monitor in real time. In addition, the use of the reagent makes it difficult to use the SNORT method at home due to the problem of the leftover reagent. A measuring apparatus using an electric measuring method is expensive. Furthermore, an electrode must be changed after a predetermined time has lapsed.

[10] The inventors of this application have performed research to solve the above- described problems and developed inventive sensors that can effectively measure the microorganism and chloride concentrations. Disclosure of Invention

Technical Solution

[11] The present invention provides a ch loride concentration-measuring sensor comprising: a voltage-measuring unit; a reference electrode connected to a first end of the voltage-measuring unit; first and second switches connected to a second end of the voltage-measuring unit in parallel; first and second operational electrodes connected to the first and second switches, respectively; third and fourth switches connected to the first operational electrode in parallel; fifth and sixth switches connected to the second operational electrode in parallel; and a power supply unit having a first end to which the third and fifth switches are connected in parallel and a second end to which the fourth and sixth switches are connected in parallel, wherein a group of second, third and sixth switches and a group of first, fourth and fifth switches are alternately opened and closed.

[12] The reference electrode may be formed of Ag/ AgCl. The operational electrode may be formed of Ag.

[13] The operation of the switches are controlled by a control unit.

[14] The present invention further provides a microorganism-detecting sensor comprising: a power supply unit; a first electrode formed of a material impairing microorganism attachment and connected to a first end of the power supply unit; a resistor and a voltage-measuring unit that are connected to a second end of the power supply in parallel; and a second electrode formed of a material facilitating the microorganism attachment and to which the resistor and the voltage-measuring unit are connected in parallel.

[15] The material impairing the microorganism attachment may be selected from the group consisting of gold, silver, platinum, iridium, zirconium, and titanium.

[16] The material facilitating microorganism attachment may be selected from the group consisting of carbon, a mixture containing 60wt% of graphite powder and 40wt% of silicon, and a glass substrate plated with gold wires each having a diameter of 0.01mm and disposed at 0.01 mm interval.

[17] The present invention further provides the chloride concentration-measuring sensor or the microorganism-detecting sensor.

[18] The water purifying apparatus may be applied to one selected from the group consisting of a water purifier, a water softener, a humidifier, and a bidet.

[19] The water purifying apparatus may further comprise a control unit and a display unit controlled by the control unit.

[20] The display unit may be a sound or visual alarming device or an LED that can indicate when a filter should be changing and when a water tank should be sterilized.

Advantageous Effects

[21] According to the present invention, since the corrosion of the electrodes can be prevented, the reliability of the sensor is improved and it becomes possible to semipermanently use the sensor. In addition, the microorganism-detecting sensor can accurately detect microorganisms contained in a liquid sample. Description of Drawings

[22] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

[23] FIG. 1 is a schematic view of a sensor for measuring a chloride concentration according to one embodiment of the present invention;

[24] FIG. 2 is a schematic view of a microorganism detecting sensor according to one embodiment of the present invention; and

[25] FIG. 3 is a schematic view of a water purifier according to an embodiment of the present invention.

Best Mode

[26] The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

[27] FIG. 1 is a schematic diagram of a chloride concentration-measuring sensor according to an embodiment of the present invention.

[28] Referring to FIG. 1, the inventive chloride concentration-measuring sensor includes a voltage-measuring unit 107, a reference electrode 109 connected to a first end of the voltage-measuring unit 107 and two operational electrodes 108 and 110 connected to a second end of the voltage-measuring unit 107 in parallel. Switches 105 and 106 are respectively connected between the operational electrode 108 and the voltage-measuring unit 107 and between the operational electrode 110 and the voltage-measuring unit 107. A power supply unit 111 is connected between the operational electrodes 108 and 110. Four switcheslOl, 102, 103, and 104 are disposed between the power supply unit 111 and the operational electrodes 108 and 110. The switches 101 and 103 are connected to the operational electrode 108 in parallel, and the switches 102 and 104 are connected to the operational electrode 110 in parallel. In addition, the switches 101 and 102 are connected to a first end of the power supply unit 111 in parallel while the switches 103 and 104 are connected to a second end of the power supply unit 111 in parallel.

[29] The voltage-measuring unit may be a potentiometer.

[30] In the chloride concentration-measuring sensor, the reference electrode 109 and the operational electrodes 108 and 110 are to be dipped in a liquid sample.

[31] The reference electrode 109 maintains a constant electric potential regardless of the liquid sample condition. The electric potentials of the operational electrodes 108 and 110 vary according to the chloride concentration in the liquid sample. Therefore, by measuring the voltage variation of the operational electrodes 108 and 110 according to the chloride concentration in the liquid sample, the chloride concentration can be measured.

[32] In the chloride concentration-measuring sensor, the reference electrode 109 may be formed of Ag/ AgCl while the operational electrodes 108 and 110 may be formed of Ag. When the operational electrodes 108 and 110 are formed of Ag, there is no health threat.

[33] A first group of the switches 101, 104 and 106 and a second group of the switches

102, 103 and 105 are alternately opened and closed. The opening/closing operation of the switches may be controlled by a control unit (not shown).

[34] The chloride is hydrolysed in the water as follows:

[35] Cl + H O → HOCl + H⁺ +Cl^" (pK = 4.6)

[36] The HOCl is ionised according to the hydrogen ion concentration of the water as follows:

[37] HOCl → H⁺ + ClO^" (pK₂ = 7.5)

[38] When the switches 101, 104 and 106 are closed and the switches 102, 103 and 105 are opened, the reference electrode 109 is connected to one end of the voltage- measuring unit 107, the operational electrode 110 is connected to the other end of the voltage-measuring unit 107, the power supply unit 111 is connected to the operational electrode 110, and the operational electrode 108 is connected to the power supply unit 111. When electric power is supplied to the sensor, reactions occurring at the operational electrodes 108 and 110 are as follows:

[39] The operational electrode (108) (Reduction): Ag⁺ + e^" → Ag

[40] The operational electrode (110) (Oxidation): HOCl + H⁺ + 2e^" → Cl^" + H O

[41] As indicated above, oxidation occurs on the operational electrode 110 according to the chloride concentration in the water, thereby varying the voltage. Reduction occurs on the operational electrode 108, thereby being refreshed.

[42] On the other hand, when the switches 101, 104 and 106 are opened and the switches

102, 103 and 105 are closed, the reference electrode 109 is connected to one end of the voltage-measuring unit 107, the operational electrode 110 is connected to the other end of the voltage-measuring unit 107, the power supply unit 111 is connected to the operational electrode 108, and the operational electrode 110 is connected to the power supply unit 111. When electric power is supplied to the sensor, oxidation occurs on the operational electrode 108, thereby varying according to the chloride concentration in the water, thereby varying the voltage. Reduction occurs on the operational electrode 110 is reduced, thereby being refreshed. [43] In the chloride concentration-measuring sensor, the oxidation/reduction occurs on the operational electrodes 108 and 110 due to the continuous switching operation. Therefore, corrosion of the electrodes can be prevented, thereby improving the reliability of the sensor and making it possible to semi-permanently use the sensor.

[44] When the voltage variation of the operational electrodes dipped in the liquid sample is outside a predetermined range, it can be determined that the chloride concentration contained in the liquid sample is high. The predetermined voltage variation range can be easily set by those of ordinary skill in the art. For example, the predetermined voltage variation range may be 50-300 mV.

[45] FIG. 2 is a schematic diagram of a microorganism-detecting sensor according to an embodiment of the present invention.

[46] Referring to FIG. 2, the inventive microorganism-detecting sensor includes a first electrode 202 formed of a material impairing the microorganism attachment and a second electrode 205 formed of a material facilitating the microorganism attachment.

[47] The material impairing the microorganism attachment may be selected from the group consisting of gold, silver, platinum, iridium, zirconium, and titanium. The material facilitating the microorganism attachment may be selected from the group consisting of carbon, a mixture of 60wt% of graphite powder and 40wt% of silicon, and a glass substrate plated with gold wires each having a diameter of 0.01mm and spaced at intervals of a 0.01 mm.

[48] In addition, the microorganism-detecting sensor further includes a power supply unit 200 connected to the first electrode 202 and a resistor 203 and a voltage- measuring unit 204 that are connected in parallel between the second electrode 205 and the power supply unit 201.

[49] The microorganisms grown in a water tank utilize organic materials in a bad- nutrition state. In addition, microorganisms attach and grow on a wall of the water tank, thereby increasing the microorganism concentration. Therefore, by using the first electrode 202 formed of the material impairing the microorganism attachment and the second electrode 205 formed of the material facilitating the microorganism attachment and measuring the voltage between the first and second electrodes 202 and 205, the microorganisms grown in the water tank can be detected. Since the microorganisms attached to the electrode generate the metabolic waste in an anaerobic state, the electric potential between the first and second electrodes 202 and 205 are directly affected. When a test parameter of an electric potential difference that can control the number of microorganisms within a limited reference range not undesirably affecting the human body after the potential difference between the first and second electrodes is compared with the colony of the microorganisms, the timing for sterilizing the water tank and exchanging the water in the water tank can be effectively noticed to the user. The test parameter of the electric potential difference may be easily set by those of ordinary skill in the art.

[50] The above-described sensors may be included in a water purifying apparatus.

[51] The water purifying apparatus may be selected from the group consisting of a water purifier, a water softener, a humidifier, and a bidet.

[52] FIG. 3 is a schematic diagram of a water purifying apparatus according to an embodiment of the present invention.

[53] Referring to FIG. 3, water (tap water) 301 is supplied to the apparatus and passes through a series of filters 302. The filtered water 304 is stored in a storage tank 303 to be released by the user.

[54] The chloride concentration-measuring sensor and/or the microorganism-detecting sensor may be provided at a variety of locations in the water purifying apparatus. Referring again to FIG. 3, the sensors may be installed near an upstream portion A of the filters 302, a portion B between the filters 302 and the storage tank 303 or a portion C in the storage tank.

[55] When the sensors are installed at the upstream portion A, it is possible to measure the chloride concentration and the presence of the microorganisms in the tap water 301. When the sensors are installed at the portion B, it is possible to measure the chloride concentration and the presence of the microorganisms in the water that have passed through the filters 302. In this case, it can be possible to determine when to change the filters 302. In addition, when the sensors are installed on the portion C, it is possible to measure the chloride concentration and the presence of the microorganisms in the water stored in the storage tank 303, and thus, it can be possible to determine when the storage tank should be cleaned and when the water in the storage tank 303 should be changed.

[56] In the above-description, although the sensors are installed at a single location, the sensors can be installed at at least two locations.

[57] When the sensors are installed at the portions A and B, it is possible to compare the chloride and microorganism concentrations of the tap water 301 flowing to the filters with the water that has passed through the filters 302, and thus, it is possible to estimate when the filters 302 should be changed. The sensors installed at the portions A and B may be connected to a microprocessor 305. According to the potential difference between the sensors connected to the microprocessor, a sound or visual alarm may be used to alert a user.

[58] When the sensors are installed at the portions A and C, it is possible to compare the chloride and microorganism concentrations of the tap water 301 flowing to the filters 302 with the water stored in the storage tank 303, and thus, it is possible to estimate when the storage tank 303 should be cleaned and when the water in the storage tank 303 should be changed . The sensors installed at the portions A and C may be connected to the microprocessor 305. According to the potential difference between the sensors connected to the microprocessor 305, a sound or visual alarm may be used to alert a user.

[59] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

[1] A chloride concentration-measuring sensor comprising: a voltage-measuring unit; a reference electrode connected to a first end of the voltage-measuring unit; first and second switches connected to a second end of the voltage-measuring unit in parallel; first and second operational electrodes connected to the first and second switches, respectively; third and fourth switches connected to the first operational electrode in parallel; fifth and sixth switches connected to the second operational electrode in parallel; and a power supply unit having a first end to which the third and fifth switches are connected in parallel and a second end to which the fourth and sixth switches are connected in parallel, wherein a group of the second, third and sixth switches and a group of the first, fourth and fifth switches are alternately opened and closed. [2] The chloride concentration-measuring sensor of claim 1, wherein the reference electrode is formed of Ag/ AgCl. [3] The chloride concentration-measuring sensor of claim 1, wherein the operational electrode is formed of Ag. [4] The chloride concentration-measuring sensor of claim 1, wherein the operation of the switches are controlled by a control unit. [5] A microorganism-detecting sensor comprising: a power supply unit; a first electrode formed of a material impairing microorganism attachment and connected to a first end of the power supply unit; a resistor and a voltage-measuring unit that are connected to a second end of the power supply in parallel; and a second electrode formed of a material facilitating the microorganism attachment and to which the resistor and the voltage-measuring unit are connected in parallel. [6] The microorganism-detecting sensor of claim 5, wherein t he material impairing the microorganism attachment is selected from the group consisting of gold, silver, platinum, iridium, zirconium, and titanium. [7] The microorganism-detecting sensor of claim 5, wherein t he material facilitating microorganism attachment is selected from the group consisting of carbon, a mixture containing 60wt% of graphite powder and 40wt% of silicon, and a glass substrate plated with gold wires each having a diameter of 0.01mm and disposed at 0.01 mm interval. [8] A water purifying apparatus comprising the sensor according to claim 1 or the sensor according to claim 5. [9] The water purifying apparatus of claim 8, wherein the water purifying apparatus is selected from the group consisting of a water purifier, a water softener, a humidifier, and a bidet. [10] The water purifying apparatus of claim 8, further comprising a control unit and a display unit controlled by the control unit. [11] The water purifying apparatus of claim 10, wherein the display unit is a sound or visual alarming device or an LED that can indicate when a filter should be changed and when a water tank should be sterilized.