Abstract:
Provided is a pen type of apparatus for measuring multiple water qualities, which is capable of measuring acidity (pH) and electric conductivity (EC) without interfering with each other in agricultural water for hydroponic cultivation to easily confirm the measured results.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2014-0014686, filed on Feb. 10, 2014, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an apparatus for measuring a water quality, and more particularly, to a pen type of apparatus for measuring multiple water qualities, which is capable of measuring acidity (pH) and electric conductivity (EC) without interfering with each other in agricultural water for hydroponic cultivation to easily confirm the measured results. 
     Description of the Related Art 
     The contamination of water today caused by municipal sewage and industrial wastewater not only destroys ecosystems, but is becoming a serious social concern by causing the depletion of water for industry and agriculture and water resources needed for drinking water. For example, while underground water is still clean, thoughtless development is leading to its accelerated depletion and contamination. 
     Recently, however, as awareness has gradually grown on the importance of managing and using water resources, various management systems for preventing the contamination of water resources and efficiently using them are being developed and implemented, so that water resources can not only be used for industry, but for household drinking water and water for living, and various other uses. 
     Meanwhile, modern living environments are becoming increasingly eco-friendly, whereby hydroponic techniques are becoming widespread in many households which directly cultivate hydroponic plants indoors such as immature stemmed plants or organic vegetables, and small fruit-bearing plants, and various types of household aquariums are being installed to control indoor temperature and humidity. In such cases, the individual households need to be supplied with water with a suitable level of quality for raising the hydroponic plants or the aquarium fish, and users need to personally manage the water to maintain it in an optimal state. 
     That is, in order to provide suitable growing conditions for a normal household to cultivate hydroponically or keep an aquarium, the quality of water used for this purpose must be continuously measured and managed in terms of water level, temperature, acidity, and electric conductivity (EC). It is particularly important that water used for hydroponics or an aquarium be measured and managed in terms of acidity (pH or hydrogen ion concentration) and EC or Total Dissolved Solids (TDS) characteristics. To this end, various types of water quality measuring devices have been disclosed so as to be easily used even by normal households. For example Korean Registered Patent No. 10-0874779 (Cited Patent Document 1) discloses a hydrogen ion concentration measuring device, and Korean Registered Patent No. 10-0865639 (Cited Patent Document 2) discloses an electric conductivity measuring device. 
     Also, multipurpose water quality measuring devices have recently been introduced that can measure both acidity and electric conductivity.  FIG. 1  is a schematic perspective view illustrating the general structure of a multipurpose water quality measuring device according to the related art, which was developed by the present applicant. As illustrated, a water quality measuring device  10  of the related art is configured of a bar-shaped housing  11  having a predetermined length, a measuring unit  12  provided on one side of the housing  11 , and a display unit  13  and a user input unit  14  provided on an outer surface of the housing  11 . A protective cap  15  for protecting a sensor of the measuring unit  12  is provided on one side of the housing. Also, while not shown, a control unit for measuring and displaying acidity and electric conductivity is provided together with a power supply unit within the housing  11 . 
     While various methods may be employed for measuring acidity and electric conductivity using a multipurpose water quality measuring device, in general, a method is used of taking measurements using a voltage that is output according to changes in the hydrogen ion concentration inside and outside a hydrogen sensitive glass bulb, and for electric conductivity, a technique is used in which a current is applied between positive and negative electrodes and the resistance that occurs across a solution in the water being measured is used. To this end, the measuring unit  12  provided on one side of the water quality measuring device  10  is configured of a pH sensor electrode  12   a  for measuring acidity, an EC sensor electrode  12   b  for measuring electric conductivity, and a temperature sensor  12   c  for measuring the temperature of the water being measured. 
     While such a water quality measuring device has the advantage that one device may be used to measure both acidity and electric conductivity, it involves the limitation that the pH sensor electrode  12   a  and the EC sensor electrode  12   b  are disposed close together so that interference occurs between the two sensor electrodes. Specifically, when the pH sensor electrode  12   a  and the EC sensor electrode  12   b  are immersed in the same water being measured, both sensor electrodes simultaneously contact the water being measured and cause interference therebetween. 
     In detail, the pH sensor electrode  12   a  is configured of a measuring electrode within the glass bulb and a reference electrode outside the glass bulb, and measurements are taken by discharging a flow of an electrolyte solution such as potassium chloride (KCl) from the reference electrode. At this point the potassium chloride flowing out from the pH sensor electrode  12   a  side is dissolved in the water being measured and changes the resistance of the water being measured so that an inaccurate value is measured by the EC sensor electrode  12   b  when the electric conductivity is measured. 
     Additionally, when the water quality measuring device is stored, the pH sensor electrode  12   a  needs to always be maintained in a state of wet contact with the electrolyte solution (KCl), while the EC sensor electrode, on the other hand,  12   b  needs to be kept in a clean state. Thus, when the electrolyte solution on the pH sensor electrode  12   a  side contacts the EC sensor electrode  12   b  and contaminates the EC sensor electrode  12   b , the inconvenience arises of having to wash the EC sensor electrode  12   b  for each use in order to maintain the clean state thereof and produce accurate electric conductivity measurements. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a pen type of apparatus for measuring multiple water qualities, which is capable of measuring acidity and electric conductivity of water to be measured by using one apparatus without interfering with each other that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
     The present invention is also directed to a pen type of apparatus for measuring multiple water qualities, in which a display part for displaying a measured value is synchronized in a direction of each of measuring sensors for measuring to automatically change a direction of a display, thereby easily confirming the result measured in each of measuring modes. 
     According to an aspect of the present invention, there is provided a pen type of apparatus for measuring multiple water qualities, the apparatus including: a housing having an accommodation space therein and a predetermined length; a first measuring module disposed on one end of the housing in a longitudinal direction to measure a first characteristic of water to be measured; a second measuring module disposed on the other end of the housing in the longitudinal direction to measure a second characteristic of the water to be measured; an inclination direction detection sensor accommodated in the housing to detect an inclined direction of the housing; a display module disposed on an outer circumferential surface of the housing to display values measured by the first and second measuring modules, wherein a first display unit for displaying the value measured by the first measuring module is disposed in one direction, and a second display unit for displaying the value measured by the second measuring module in the other opposite direction to overlap each other; and a control module accommodated in the housing to control measuring operations of the first and second measuring modules according to the inclined direction of the housing, which is detected by the inclination direction detection sensor, the control module controlling the display module so that each of the values measured by the first and second measuring modules is displayed on the display module through the first or second display unit. 
     The first measuring module may include an acidity measuring module for measuring acidity of the water to be measured, and the second measuring module may include an electric conductivity measuring module for measuring electric conductivity of the water to be measured. 
     The inclination direction detection sensor may include a gyro sensor. 
     The apparatus may further include a manipulation unit disposed on the outer circumferential surface to input a user command. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective of a water quality measuring apparatus according to a related art. 
         FIG. 2  is a front view of a water quality measuring apparatus according to an embodiment of the present invention. 
         FIG. 3  is a block diagram illustrating constitutions of the water quality measuring apparatus according to an embodiment of the present invention. 
         FIGS. 4A and 4B  are side views of an acidity measuring module and an electric conductivity measuring module, respectively, which are main parts of  FIG. 2 . 
         FIGS. 5A, 5B, and 5C  are front views of a display module that is a main part of  FIG. 2  and display units. 
         FIG. 6  is a view illustrating an acidity measuring state using the water quality measuring apparatus of  FIG. 2 . 
         FIG. 7  is a view illustrating an electric conductivity measuring state using the water quality measuring apparatus of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention and the technical objects achieved by the embodiment of the present invention will be clear by the exemplary embodiments that are described below. Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. 
       FIG. 2  is a front view of a water quality measuring apparatus according to an embodiment of the present invention,  FIG. 3  is a block diagram illustrating constitutions of the water quality measuring apparatus according to an embodiment of the present invention,  FIGS. 4A and 4B  are side views of an acidity measuring module and an electric conductivity measuring module, respectively, which are main parts of  FIG. 2 .  FIGS. 5A, 5B , and  5 C are front views of a display module that is a main part of  FIG. 2  and display units. In descriptions of the present invention, the same or similar parts are denoted by the same reference numerals although they are differently shown. 
     As illustrated in  FIGS. 2 and 3 , a water quality measuring apparatus  100  according to the present invention includes a bar-shaped housing  110  having a predetermined length, an acidity measuring module  120  (hereinafter, referred to as a “pH measuring module”) disposed on one end of the housing  110 , an electric conductivity measuring module  130  (hereinafter, referred to as an “EC measuring module”) disposed on the other end of the housing  110 , and a display module  140  disposed on an outer circumferential surface of the housing  110 . Also, an inclination direction detection sensor  150  for detecting an inclined direction of the water quality measuring apparatus  100 , a control module  160  for controlling operations of the pH measuring module  120  and the EC measuring module  130  and a display operation of the display module  140 , and a power source module  170  providing a power for operating the water quality measuring apparatus  100  are built in the housing  110 . Also, a manipulation unit  180  for inputting a user command is disposed on an outer circumferential surface of the housing  110 . In the water quality measuring apparatus  100  including the above-described constitutions, a protection cap (see reference numeral  190  of  FIGS. 6 and 7 ) may be coupled to the housing  110  outside the pH measuring module  120  and the EC measuring module  130  to protect the measuring modules  120  and  130 . 
     Here, the housing  110  may provide a main body of the measuring apparatus  100  for accommodating the various constitutions therein. For this, the housing  110  may have an accommodation space therein and a bar type having a predetermined length. Also, the housing  110  may have a circular or oval shape in cross-section to allow a user to grasp the housing  110 . Also, the housing  110  may be injection-molded by using a plastic material. The pH measuring module  120 , the EC measuring module  130 , and the display module  140  may be coupled to the inside and outside of the housing  110  to maintain sealing of the housing  110 . 
     The pH measuring module  120  may be a part for measuring acidity (i.e., hydrogen ion concentration) of water to be measured (hereinafter, referred to as “measured water”). Here, a pH meter that measures acidity by using a voltage outputted according to a change in hydrogen ion concentration inside and outside a hydrogen sensitive glass bulb may be used as the pH measuring module  120 . For this, as illustrated in  FIG. 4A , the pH measuring module  120  may include a pH sensor electrode  121  including a measuring electrode and a reference electrode. Also, the pH measuring module  120  may further include a temperature sensor electrode  122  for measuring a temperature of the measured water to compensate a pH value according to the temperature of the measured water. The pH measuring module  120  may be coupled to one end of the housing  110 . Also, the pH measuring module  120  may be connected to the control module  160  that is provided within the housing  110  to operate according to a control signal of the control module  160 . 
     The EC measuring module  130  may be a part for measuring electric conductivity of the measured water. Here, an EC meter applying current between both electrodes to measure electric conductivity by using resistance generated in a solution of the measured water may be used as the EC measuring module  130 . For this, as illustrated in  FIG. 4B , the EC measuring module  130  may include an EC sensor electrode  131  including a pair of conductive electrodes that are spaced a predetermined distance from each other. Here, a temperature sensor electrode  132  for measuring a temperature of the measured water to compensate an EC value according to the temperature of the measured water. The EC measuring module  130  may be coupled to the other end (i.e., a side opposite to the pH measuring module) of the housing  110  to operate according to a control signal of the control module  160 . 
     The display module  140  may be a part for displaying the acidity and electric conductivity which are measured by the pH measuring module  120  and the EC measuring module  130 . Here, the acidity and electric conductivity may be alternately displayed on one display window. For this, a pH display unit  141  and an EC display unit  142  may be displayed on the display window at the same time. Particularly, as illustrated in  FIG. 5C , the pH display unit  141  and the EC display unit  142  may be disposed so that the display units that are capable of mutually displaying the measured values overlap each other and are displayed in reverse directions. That is, as illustrated in  FIG. 5B , the acidity may be displayed by the pH display unit  141  in one direction, and as illustrated  FIG. 5C , the electric conductivity may be displayed by the EC display unit  142  in the other opposite direction. 
     The inclination direction detection sensor  150  may be a part for detecting whether the water quality measuring apparatus  100  is in an acidity measuring mode or electric conductive measuring mode with respect to the pH measuring module  120  and EC measuring module  130 , which are spaced apart from each other at both ends of the housing  110 . Since the water quality measuring apparatus has a predetermined length and both ends to which the pH measuring module  120  and the EC measuring module  130  are coupled, the water quality measuring apparatus (i.e., housing) may be inclined in a specific direction to measure the acidity and electric conductivity. Thus, the inclination direction detection sensor  150  may detect an inclined direction of the housing  110  to detect whether the water quality measuring apparatus is in the acidity measuring mode or electric conductivity measuring mode. A gyro sensor may be used as the inclination direction detection sensor  150 . The inclination direction detection sensor  150  may be disposed within the housing  110  to detect an inclination and direction of the housing  110 . 
     The power source module  170  may be a part for supplying a power required for operating the devices such as the pH measuring module  120 , the EC measuring module  130 , the display module  140 , and the control module  160 . The power source module  170  may be directly connected to an external power source. However, the power source module  170  may be provided as a general changeable battery or a charging module that is chargeable by using the external power source. 
     The control module  160  may be a part for controlling an overall operation of the water quality measuring apparatus. That is, the control module  160  may control the pH measuring module  120  and the EC measuring module  130  to measure the acidity and electric conductivity and compensate the measured values according to the temperature, thereby displaying the compensated values through the display module  140 . Particularly, the pH measuring module  120  and the EC measuring module  130  may operate according to the inclined direction of the water quality measuring apparatus, which is detected by the inclination direction detection sensor  150 , and simultaneously, the measured values may be displayed through the pH display unit  141  or the EC display unit  142 . That is, when the control module  160  determines that the water quality measuring apparatus is in the acidity measuring mode according to the detected result of the inclination direction detection sensor  150 , the control module  160  may control an operation of the pH sensor electrode  121  through a pH power source control unit  123 . Also, when the control module  160  determines that the water quality measuring apparatus is in the electric conductivity measuring mode, the control module  160  may control an operation of the EC sensor electrode  131  through an EC power source control unit  133 . The control module  160  may include a central processing unit  161  for controlling an operation of each device, an AD converter  162  for converting the values measured by the pH measuring module  120  and the EC measuring module  130  into digital values, and a memory  163  for storing various data. 
     The manipulation unit  180  may be a part for inputting a control command by the user. The manipulation unit  180  may include a button switch for turning on/off the water quality measuring apparatus  100 . 
       FIG. 6  is a view illustrating an acidity measuring state using the water quality measuring apparatus of  FIG. 2 , and  FIG. 7  is a view illustrating an electric conductivity measuring state using the water quality measuring apparatus of  FIG. 2 . 
     As illustrated in  FIG. 6 , when it is intended to measure the acidity of the measured water, the user may immerse the pH measuring module  120  disposed at one side into the measured water. Here, the pH measuring module  120  of the water quality measuring apparatus  100  may be inclined downward. Here, the inclination direction detection sensor  150  may detect whether the water quality measuring apparatus  100  is in the acidity measuring mode by the inclined direction, and the control module  160  may operate the pH measuring module  120  according to the signal detected by the inclination direction detection sensor  150  to measure acidity of the measured water, thereby displaying the measured result on the pH display unit  141  of the display module  140 . 
     Similarly, as illustrated in  FIG. 7 , when it is intended to measure the electric conductivity of the measured water, the user may immerse the EC measuring module  130  disposed at the other side into the measured water. Here, the EC measuring module  130  of the water quality measuring apparatus  100  may be inclined downward. Here, the inclination direction detection sensor  150  may detect whether the water quality measuring apparatus  100  is in the electric conductivity measuring mode by the inclined direction, and the control module  160  may operate the EC measuring module  130  according to the signal detected by the inclination direction detection sensor  150  to measure electric conductivity of the measured water, thereby displaying the measured result on the EC display unit  142  of the display module  140 . 
     As described above, in the water quality measuring apparatus  100 , the pH measuring module  120  and the EC measuring module  130  may be coupled to both sides of the housing  110  without interfering with each other to measure accurate values. Since the values corresponding to the acidity and the electric conductivity which are measured in the opposite directions are displayed in the opposite directions, the user may easily confirm the measured value in the each mode. 
     In the descriptions of the present invention, although the pH measuring module and the EC measuring module are exemplified as the measuring modules, the present invention is not limited thereto. For example, the pH measuring module and the EC measuring module may be substituted with a pair of measuring modules for measuring different characteristics to various characteristics of the water quality. 
     According to the present invention, since the first measuring module (the pH measuring module) and the second measuring module (the EC measuring module) for measuring the water quality characteristics different from each other are disposed on both ends of the housing in a longitudinal direction, each of the measuring modules may accurately measure the water quality without interfering with each other because interruption factors generated from the pH electrode sensor preservation solution and the conductive solution discharged from the reference are removed. 
     Also, the first and second measuring modules may be selectively operated in the inclined direction of the measuring apparatus by the inclination direction detection sensor without performing a separate manipulation to measure the corresponding water quality characteristic. 
     Also, the first and second display units for displaying the values measured by the first and second measuring modules are disposed to turn around and overlap each other. Also, while the first and second display units are inclined in directions different from each other, the value measured by the first and second measuring modules may be respectively displayed on the corresponding display units. Thus, the user may easily confirm the measured values. 
     Also, it may be unnecessary to provide separate devices for measuring the acidity and electric conductivity. 
     Accordingly, a person having ordinary skill in the art will understand from the above that various modifications and other equivalent embodiments are also possible.