Patent Publication Number: US-2022221323-A1

Title: Water-level measuring device using gear ratio

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2021-0005396, filed on Jan. 14, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Field 
     One or more embodiments relate to a water-level measuring device using a gear ratio, and more particularly, to a water-level measuring device using a gear ratio, the water-level measuring device measuring a water level by using a weight balance between a plot and a weight pendulum and measuring a water level of a water pool in a non-power mechanical fashion through a gear ratio between a first gear connected to the plot and a cable and a second gear connected to the weight pendulum. 
     2. Description of the Related Art 
     In general industrial sites, a water gauge for measuring a water surface of various tanks and heaters is used. The water gauge used in the industrial sites may include a reflex-type water gauge, a plain glass-water gauge, etc. 
     However, these water gauges are problematic as below. The reflex-type water gauge, the plain glass-water gauge, etc. check a water surface from the outside by observing the water surface through transparent glass, and due to contamination of a glass portion for identifying a water surface or interference with a steam portion, it may be difficult to identify the water surface. 
     In the case of one or more water pools used in the industrial sites, it may be difficult to apply the water gauge, and thus, the water level is measured by using a measuring device, such as ultrasonic waves, a radar, a laser, etc. The measuring of the water level by using the measuring device, such as the ultrasonic waves, the radar, the laser, etc., uses waves reflected by the ultrasonic waves, the radar, the laser, etc. 
     However, the previous water gauge used in the industrial sites has the following problems. When the water level is measured by using the waves reflected by the ultrasonic waves, the radar, the laser, etc., an error may occur in the measurement of the water level due to diffused reflection generated on a water surface. 
     Also, vapors or bubbles are generated in a high-temperature environment, and in an environment in which the vapors or bubbles are generated, it may be difficult to use an ultrasonic measuring device. 
     In addition, in the case of a previous water-surface gauge and a previous water-level gauge, a measuring device is arranged in a vertically upper area of a region for which a water surface and a water level are to be measured. However, in the case of a region exposed to a hazardous environmental condition, due to for example radioactivity, corrosiveness, and acidity, it may be difficult to manage and maintain the measuring device. 
     Also, the previous water-level gauge uses electricity and electronic equipment, and thus, may have to be mounted in a location appropriate for the mounting of the electricity and the electronic equipment. However, in the case of the region exposed to the hazardous environmental condition, due to for example radioactivity, corrosiveness, and acidity, it may be difficult to mount the water-level gauge. 
     SUMMARY 
     One or more embodiments relate to a water-level measuring device using a gear ratio, and more particularly, to a water-level measuring device using a gear ratio, the water-level measuring device measuring a water level by using a weight balance between a plot and a weight pendulum and measuring a water level of a water pool in a non-power mechanical fashion through a gear ratio between a first gear connected to the plot and a cable and a second gear connected to the weight pendulum. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure. 
     According to one or more embodiments, a water-level measuring device measuring a water level by using a gear ratio includes: a water pool filled with a liquid; a plot receiving buoyancy by being floated over a water surface of the liquid filled in the water pool; a cable connected to the plot and extending to the outside of the water pool; a first gear connected with the cable; a second gear connected with the first gear; a weight pendulum connected with the second gear and moving in up and down directions, wherein when the water level of the water pool descends, the weight pendulum ascends due to a weight of the plot, and when the water level of the water pool ascends, the weight pendulum descends due to the buoyancy of the plot. 
     The water-level measuring device may further include a water-level indicator connected with the first gear and configured to indicate the water-level of the water pool to the outside via rotation of the first gear. 
     The weight of the plot may be greater than a weight of the weight pendulum, and the weight of the weight pendulum may be greater than a weight of the cable. 
     The weight of the plot may be greater than a sum of the weight of the weight pendulum and the weight of the cable. 
     The water pool may include a support wall which vertically extends and into which the plot is inserted. 
     The water-level measuring device may further include a connector connected with the weight pendulum and configured to slidingly move in up and down directions and a bracket which vertically extends and into which the connector is inserted. 
     The water-level measuring device may further include a water-surface indicator connected with the weight pendulum and arranged outside the water pool, the water-surface indicator being configured to indicate a level of the water surface of the water pool. 
     The water-level measuring device may further include a water-level transmitter including a space into which the weight pendulum is inserted and in which the weight pendulum is configured to move, wherein the weight-level transmitter may be configured to transmit a signal to the outside according to a movement of the weight pendulum. 
     The water-level transmitter may include: a housing including a space into which the weight pendulum is inserted and in which the weight pendulum is configured to move; an input terminal connected with the housing and configured to supply a voltage; and an output terminal connected with the housing and configured to generate a voltage according to the movement of the weight pendulum. 
     The input terminal may include a battery. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a view of a water-level measuring device using a gear ratio, according to an embodiment; 
         FIG. 2  is a view illustrating that a cable and a weight pendulum are connected to each other through a first gear and a second gear, and the cable and a water-level indicator are connected to each other through the first gear and a third gear; 
         FIG. 3  is a view of a water-level indicator according to an embodiment; 
         FIG. 4  is a view of a water-surface indicator connected to a weight pendulum according to an embodiment; 
         FIG. 5  is a view illustrating a water-level transmitter configured to generate a signal to the outside according to a motion of a weight pendulum, according to an embodiment; and 
         FIG. 6  is a view illustrating an input terminal and an output terminal provided in a water-level transmitter, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. 
     In this specification, principles of the disclosure are described and embodiments are disclosed, in order to clarify the scope of the claims of the disclosure and clearly convey the disclosure for one of ordinary skill in the art to implement the disclosure. Embodiments may be implemented in various forms. 
     The terms “comprises” or “comprising” used in various embodiments of the disclosure specify the presence of disclosed functions, operations, components, or the like, but do not preclude the addition of one or more functions, operations, components, or the like. It will be further understood that the terms “comprises” or “comprising” used herein specify the presence of stated features, integers, steps, operations, members, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and/or groups thereof. 
     When it is described that one or more components are “connected” or “coupled” to another component, it should be understood that the one or more components may be directly connected or coupled to the other component, but other intervening components may also be present between the one or more components and the other component. In contrast, when an element is referred to as being “directly on,” “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. 
     Although the terms first, second, etc. used in this specification may be used herein to describe various elements, these terms do not limit the components. These terms are only used to distinguish one element from another. 
     One or more embodiments relate to a water-level measuring device using a gear ratio, and more particularly, to a water-level measuring device using a gear ratio, the water-level measuring device measuring a water level by using a weight balance between a plot and a weight pendulum and measuring a water level of a water pool in a non-power mechanical fashion through a gear ratio between a first gear connected to the plot and a cable and a second gear connected to the weight pendulum. Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. 
     Referring to  FIG. 1 , a water-level measuring device using a gear ratio according to an embodiment may include a water pool  110 , a plot  120 , a cable  130 , a first gear  140 , a second gear  150 , and a weight pendulum  160 . 
     The water pool  110  may be filed with a liquid. The water pool  110  may include various tanks and heaters used in industrial sites and may include various types of water pools which may be filled with a liquid. 
     The plot  120  may receive buoyancy from the liquid of the water pool  110 , by floating over a water surface of the liquid filled in the water pool  110 . The plot  120  may include various materials which may receive buoyancy from the liquid of the water pool  110 . 
     The cable  130  may be connected to the plot  120  and may extend to the outside of the water pool  110 . Referring to  FIG. 1 , the cable  130  may be supported by a supporter  131  and may extend to the outside of the water pool  110 . The cable  130  may maintain tension while being connected to the plot  120 , and the plot  120  may be vertically moved through the cable  130 . 
     Referring to  FIG. 2 , the first gear  140  may be connected to the cable  130 . The first gear  140  may rotate via the movement of the cable  130  and may be connected with the second gear  150 . 
     The second gear  150  may be connected with the first gear  140 . The first gear  140  and the second gear  150  may be connected with each other through a first connection chain  141 . The weight pendulum  160  may be connected with the second gear  150  and may move in up and down directions. 
     The second gear  150  may rotate via the movement of the weight pendulum  160 , and via the rotation of the second gear  150 , the first gear  140  may rotate. When the first gear  140  rotates, the cable  130  may move via the first gear  140 . The weight pendulum  160  may be directly connected to the second gear  150 . However, the weight pendulum  160  may be connected to the second gear  150  through other components, such as an auxiliary gear  153 . 
     The water-level measuring device using the gear ratio according to an embodiment may measure a water level of the water pool  110  through the movements of the plot  120 , the cable  130 , the first gear  140 , the second gear  150 , and the weight pendulum  160 . 
     According to an embodiment, a weight of the plot  120  may be greater than a weight of the weight pendulum  160 , and the weight of the weight pendulum  160  may be greater than a weight of the cable  130 . In addition, the weight of the plot  120  may be greater than a sum of the weight of the weight pendulum  160  and the weight of the cable  130 . 
     Hereinafter, an operating method of the water-level measuring device using the gear ratio is described in detail, according to an embodiment. 
     When a water-level of the water pool  110  stands still, the weight of the plot  120 , to which buoyancy is applied, and the weight of the weight pendulum  160  may form a balance. Here, when the water level of the water pool  110  falls, the buoyancy applied to the plot  120  may be reduced. 
     As described above, the weight of the plot  120  may be greater than the sum of the weight of the weight pendulum  160  and the weight of the cable  130 , and thus, when the buoyancy applied to the plot  120  is reduced, the plot  120  may descend due to the weight of the plot  120 . 
     When the plot  120  descends, the cable  130  connected with the plot  120  may be pulled down, and thus, the first gear  140  may rotate, and via the rotation of the first gear  140 , the second gear  150  may rotate. 
     The weight pendulum  160  may ascend via the rotation of the second gear  150 . When the plot  120  descends and reaches a descending water level of the water pool  110 , the plot  120  may receive again the buoyancy from the liquid of the water pool  110 . When the plot  120  receives the buoyancy again, the weight of the plot  120  and the weight of the weight pendulum  160  may form a balance, so that the plot  120  may stop descending. 
     When the water level of the water pool  110  rises, buoyancy may be additionally generated in the plot  120 , and thus, the tension of the cable  130  may be loosened. When the tension of the cable  130  is loosened, the weight of the weight pendulum  160  may become greater than the weight of the plot  120  to which the buoyancy is applied. 
     When the weight of the weight pendulum  160  increase, the weight pendulum  160  may descend, and when the weight pendulum  160  descends, the second gear  150  connected with the weight pendulum  160  may rotate. 
     When the second gear  150  rotates, the first gear  140  may also rotate, and via the rotation of the first gear  140 , the cable  130  may be wound. When the cable  130  is wound, the tension of the cable  130  may be maintained, and the plot  120  may ascend. When the plot  120  ascends and reaches an ascending level of the water pool  110 , a portion of the buoyancy applied to the plot  120  may be eliminated. 
     When the portion of the buoyancy applied to the plot  120  is eliminated, the weight of the plot  120  and the weight of the weight pendulum  160  may form a balance, and thus, the plot  120  may stop ascending. 
     Based on this method, the locations of the plot  120 , the cable  130 , and the weight pendulum  160  may be changed according to a level of the water surface of the water pool  110 . The water-level measuring device using the gear ratio according to an embodiment may measure the water level and the water surface of the water pool  110  according to the locations of the cable  130  and the weight pendulum  160  that are changed according to the water surface of the water pool  110 . 
     The cable  130  and the weight pendulum  160  may be connected with a measuring portion  170  configured to measure the water level and the water surface of the water pool  110 , through a gear, etc., and the water level and the water surface of the water pool  110  may be indicated to the outside through the measuring portion  170 . 
     Here, movement distances of the cable  130  and the weight pendulum  160  may be different from each other. The movement distance of the weight pendulum  160  may be less than the movement distance of the cable  130 , and thus, by adjusting a gear ratio between the first gear  140  and the second gear  150 , the relative movement distance between the cable  130  and the weight pendulum  160  may be adjusted. 
     The gear ratio between the first gear  140  and the second gear  150  may be changed according to a mounting environment (a weight of the weight pendulum, a length of the cable, etc.) of the plot  120 , the cable  130 , and the weight pendulum  160 . Also, types of the first gear  140  and the second gear  150  may be changed according to the mounting environment of the plot  120 , the cable  130 , and the weight pendulum  160 . 
     Also, a type of the first connection chain  141  configured to connect the first gear  140  with the second gear  160  may also be changed according to the mounting environment of the plot  120 , the cable  130 , and the weight pendulum  160 . 
     A previous water-surface and water-level measuring device may directly measure a water surface and a water level in a location near to a region to be measured, and thus, in an environmental condition hazardous due to radioactivity, acidity, corrosiveness, etc., it may be difficult for an operator to maintain and manage the measuring device. 
     Referring to  FIG. 1 , the cable  130  according to an embodiment may extend to the outside of the water pool  110 . Because the cable  130  extends to the outside of the water pool  110 , the water level of the water pool  110  may be measured from other locations than a region where environment conditions are hazardous due to, for example, radioactivity, acidity, corrosiveness, etc. 
     The water-level measuring device using the gear ratio according to an embodiment may further include a water-level indicator  171 . The water-level indicator  171  may be connected with the first gear  140 , and thus, may indicate the water level of the water pool  110  to the outside according to the rotation of the first gear  140 . 
     Referring to  FIG. 2 , the water-level indicator  171  may be connected with a third gear  151 , and the third gear  151  may be connected with the first gear  140 . The third gear  151  may be connected with the first gear  140  through a second connection chain  152 , and when the first gear  140  rotates, the third gear  151  may also rotate. 
     The water-level indicator  171  may be configured to indicate the water level of the water pool  110  to the outside, and the water level of the water pool  110  may be changed due to the rotation of the third gear  151 . 
     The first gear  140  may rotate via the cable  130 , and according to a location of the cable  130 , a rotation location of the first gear  140  may also be changed. As described above, the location of the cable  130  may be changed according to the water level of the water pool  110 , and thus, the rotation location of the first gear  140  may also be changed according to the water level of the water pool  110 . The water-level indicator  171  may be configured to indicate the water level by using the rotation location of the first gear  140  that is changed according to the water level of the water pool  110 . 
     Referring to  FIG. 3 , the water-level indicator  171  may include a water-level display  171   a  configured to display the water level of the water pool  110  to the outside, and the water-level display  171   a  may display the water level of the water pool  110  by using a number. However, the water-level display  171   a  is not limited thereto, and the water-level display  171   a  may display the water level of the water pool  110  by using various other available ways and structures which may enable recognition by the outside. 
     The water-level measuring device using the gear ratio according to an embodiment may further include a water-surface indicator  172 . The water-surface indicator  172  may be connected to the weight pendulum  160  and may be arranged outside the water pool  110 . The water-surface indicator  172  may indicate a level of the water surface. 
     Referring to  FIG. 4 , the water-surface indicator  172  may be moved while being synchronized with the weight pendulum  160 . As described above, the location of the weight pendulum  160  may be changed according to the water level of the water pool  110 , and the water-surface indicator  172  may indicate the water surface of the water pool  110  to the outside based on the changed location of the weight pendulum  160 . 
     According to an embodiment, the water-surface indicator  172  may be arranged on a line that extends in parallel with the water surface of the water pool  110 , and the level of the water surface of the water pool  110  may be identified in the outside through the water-surface indicator  172 . 
     The cable  130  according to an embodiment may extend to the outside of the water pool  110 , and thus, the water level and the water surface of the water pool  110  may be measured in a location other than a location where environmental conditions are hazardous due to, for example, radioactivity, acidity, corrosiveness, etc. 
     The water-level indicator  171  may be mounted at a safe external wall  10 , rather than a location of the hazardous environmental condition due to radioactivity, acidity, corrosiveness, etc., and the water-surface indicator  172  may also be mounted at a safe location to observe the water surface of the water pool  110 . 
     According to an embodiment, a gear ratio of the first gear  140 , the second gear  150 , and the third gear  151  may be changed to indicate the water level of the water pool  110  by using the water-level indicator  171 . Also, the gear ratio of the first gear  140 , the second gear  150 , and the third gear  151  may be changed to indicate the water surface of the water pool  110  by using the water-surface indicator  172 . 
     That is, the water-level measuring device using the gear ratio according to an embodiment may adjust the gear ratio of the first gear  140 , the second gear  150 , and the third gear  151  to indicate the water level and the water surface of the water pool  110  to the outside through the relative locations of the plot  120 , the cable  130 , and the weight pendulum  160 . 
     However, the water-level measuring device using the gear ratio according to an embodiment is not limited to including the first gear  140 , the second gear  150 , and the third gear  151  and may further include other gears according to necessity. 
     According to an embodiment, the support wall  111  which vertically extends and into which the plot  120  is inserted may be provided in the water pool  110 . The plot  120  may float over the water surface of the water pool  110  and may move along the water surface of the water pool  110 . 
     When the plot  120  moves along with the water surface of the liquid, the plot  120  may sway in right and left directions due to waves or bubbles generated on the water surface. The support wall  111  may be configured to prevent the swaying of the plot  120 , and the support wall  111  may be provided to have a slightly greater width than the plot  120 . 
     The swaying of the plot  120  in the right and left directions due to waves or bubbles of the water surface may be minimized by the support wall  111 , and thus, the accuracy of the water-level measuring device using the gear ratio according to an embodiment may be improved. 
     The weight pendulum  160  may be connected to the second gear  150 , and the weight pendulum  160  may be connected to the second gear  150  through a connector  161  and a bracket  162 . 
     Referring to  FIGS. 2 and 4 , the connector  161  may be connected to the weight pendulum  160  and may slidingly move in up and down directions. The connector  161  may be configured to slidingly move in up and down directions according to the up and down movement of the weight pendulum  160 , and the weight pendulum  160  and the second gear  150  may be connected with each other by the connector  161 . The connector  161  may be directly connected with the second gear  150  or may be connected with the second gear  150  through the auxiliary gear  153 . 
     The bracket  162  may vertically extend and the connector  161  may be inserted into the bracket  162 . The weight pendulum  160  may move in up and down directions, and when the weight pendulum  160  moves in up and down directions, the weight pendulum  160  may sway in right and left directions. 
     The bracket  162  may be configured to prevent the swaying of the weight pendulum  160 . The bracket  162  may vertically extend and restrict the right and left movement of the connector  161 , so that the connector  161  may move only in up and down directions and may not sway in right and left directions. 
     The right and left movement of the connector  161  may be restricted by the bracket  162 , and thus, the weight pendulum  160  connected with the connector  161  may be prevented from swaying in right and left directions. 
     The water-level measuring device using the gear ratio according to an embodiment may indicate the water level and the water surface of the water pool  110  through the water-level indicator  171  and the water-surface indicator  172 . However, the water-level measuring device using the gear ratio is not limited to using the water-level indicator  171  and the water-surface indicator  172 . The water-level measuring device using the gear ratio according to an embodiment may include various measuring devices. 
     Referring to  FIGS. 5 and 6 , the water-level measuring device using the gear ratio according to an embodiment may further include a water-level transmitter  180  configured to transmit a signal for measuring a water level of the water pool  110  to the outside. 
     The water-level transmitter  180  may be configured to transmit the signal corresponding to the water level of the water pool  110  to the outside. The water-level transmitter  180  may transmit the signal to the outside according to a movement of the weight pendulum  160 . The water-level transmitter  180  may include a space into which the weight pendulum  160  may be inserted and in which the weight pendulum  160  may move. 
     Referring to  FIGS. 5 and 6 , the water-level transmitter  180  may include a housing  181 , an input terminal  182 , and an output terminal  183 . 
     The housing  181  may include a space into which the weight pendulum  160  may be inserted and in which the weight pendulum  160  may move. The input terminal  182  and the output terminal  183  may be connected to the housing  181  and may include an electric wire coil. 
     The input terminal  182  may be connected to the housing  181  and may be configured to supply a voltage. The output terminal  183  may be connected to the housing  181  and may be configured to generate a voltage according to a movement of the weight pendulum  160 , wherein the voltage generated by the output terminal  183  may be the signal transmitted to the outside. 
     As described above, the weight pendulum  160  may move according to a water level of the water pool  110 . When the weight pendulum  160  moves according to a change in the water level of the water pool  110 , the weight pendulum  160  may move while being inserted into the housing  181 . Here, the weight pendulum  160  may include a material for generating the voltage in the output terminal  183  according to the movement of the weight pendulum  160 . 
     When the input terminal  182  included in the housing  181  supplies a voltage, and the weight pendulum  160  is inserted into the housing  181  and moves, the output terminal  183  may generate a voltage. 
     The voltage generated by the output terminal  183  may be changed according to up and down movement of the weight pendulum  160 . The voltage changed according to the up and down movement of the weight pendulum  160  may be transmitted to the outside, and the water level of the water pool  110  may be identified by detecting the voltage. 
     The water-level transmitter  180  may be configured to transmit water level information to the outside of the water pool  110 . The water level information of the water pool  110  may be identified outside the water pool  110  through the water-level transmitter  180 . 
     Referring to  FIG. 6 , the input terminal  182  may include a battery. The input terminal  182  may receive power from the outside and there may be a risk of blockage of the power supply according to an external environment. 
     However, when the battery is included in the input terminal  182 , even when power is lost according to a change in the external environment, the voltage may be supplied through the input terminal  182 . In detail, when the power is lost according to a change in the external environment, a relay voltage may be lost, and thus, a switch is changed from an off-state to an on-state, so that power may be applied from the battery for a predetermined period of time. Based on this operation, the reliability of the water-level measuring device using the gear ratio according to an embodiment may be improved. 
     The water-level measuring device using the gear ratio according to an embodiment may have the following effects. 
     The water-level measuring device using the gear ratio according to an embodiment may measure a water level by using a weight balance of the plot and the weight pendulum and may measure a water level of the water pool in a non-power mechanical fashion by using the gear ratio between the first gear connected with the plot and the cable and the second gear connected with the weight pendulum. Thus, the water-level measuring device using the gear ratio may measure the water level without being affected by an external environment. 
     Also, the water-level measuring device using the gear ratio according to an embodiment may measure a water surface by making the cable connected with the plot extend to the outside of the water pool to be connected with the weight pendulum, and then, measuring the water surface through the weight pendulum. Thus, the water surface of the water pool which is not available for measurement due to an external environment may be measured without deteriorating the readability of the water gauge. 
     In particular, the water-level measuring device using the gear ratio according to an embodiment may not physically read a level of the water surface in the water pool. Rather, the water-level measuring device may recognize the level of the water surface through the plot, the cable, and the weight pendulum, and thus, the readability and the accuracy may be improved, compared with a previous water gauge. 
     Also, the water-level measuring device using the gear ratio according to an embodiment may simultaneously measure the water surface and the water level by making the cable connected with the plot extend to the outside of the water pool and connecting the cable with the weight pendulum. 
     Also, the water-level measuring device using the gear ratio according to an embodiment may make the cable connected with the plot extend to the outside of the water pool and may mount the measuring portion outside the water pool, and thus, an exposure of an operator to an external environment during a maintenance operation of the measuring portion may be minimized. 
     The previous water-surface and water-level measuring device may directly measure a water surface and a water level in a location adjacent to a region to be measured, and thus, where environmental conditions are harmful due to, for example, radioactivity, acidity, corrosiveness, etc., it may be difficult for an operator to maintain and manage the measuring portion. 
     However, the water-level measuring device using the gear ratio according to an embodiment may mechanically measure the water surface and the water level by using the plot, the cable, and the weight pendulum, and thus, may semi-permanently measure the water surface and the water level. 
     Also, the water-level measuring device using the gear ratio according to an embodiment may make the cable connected to the plot extend to the outside of the water pool and connect the cable with the weight pendulum, and thus, the measuring portion may be mounted to be apart from the region to be measured. Thus, it may be possible to mount the measuring portion in a region having an environmental condition (with respect to radioactivity, acidity, corrosiveness, etc.) having a good accessibility for an operator. 
     In addition, in the case of a previous measuring device using an indirect measuring method, such as a measuring device using ultrasonic waves, laser beams, etc., it may be highly probable that an error may occur according to a mounting environment, etc. However, the water-level measuring device using the gear ratio according to an embodiment may not use electrical and electronic equipment and may use non-power mechanical equipment. Thus, a probability of error occurrence may be reduced, and the reliability of the operation of the measuring device may be improved. 
     According to an embodiment, a water level may be measured by using a weight balance of the plot and the weight pendulum, and a water level of the water pool may be measured in a non-power mechanical fashion by using the gear ratio between the first gear connected with the plot and the cable and the second gear connected with the weight pendulum. Thus, the water level may be measured without being affected by an external environment. 
     Also, according to an embodiment, a water surface may be measured by making the cable connected with the plot extend to the outside of the water pool to be connected with the weight pendulum, and then, measuring the water surface through the weight pendulum. Thus, the water surface of the water pool which is not available for measurement due to an external environment may be measured without deteriorating the readability of the water gauge. 
     Also, according to an embodiment, a water surface and a water level may be simultaneously measured by making the cable connected with the plot extend to the outside of the water pool and connecting the cable with the weight pendulum. Also, the cable connected with the plot may extend to the outside of the water pool, and the measuring portion may be mounted outside the water pool, and thus, an exposure of an operator to an external environment during a maintenance operation of the measuring portion may be minimized. 
     Furthermore, according to an embodiment, electrical and electronic equipment may not be used, and non-power mechanical equipment may be used. Thus, a probability of the error occurrence may be reduced, and the reliability of the operation of the measuring device may be improved. 
     It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, 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 as defined by the following claims.