JP2005306393A - Method and device for measuring amount of evaporation of liquid in tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for measuring the amount of evaporation of a liquid in a tank. <P>SOLUTION: The device 10 for measuring the amount of evaporation of the liquid in the tank comprises a measuring container 40 inserted in the underground tank 12 through a detecting hole 20, a float 42 which gives the measuring container 40 buoyancy so that a liquid level 41 of the measuring container 40 is kept almost correspondent to a liquid level 34 of the underground tank 12, a weigher 44 for weighing the measuring container 40, and a processing unit 46 which memorizes a weight measured by the weigher 44 and computes an amount of generation of oil vapor from the oil stored in the underground tank 12. The measuring container 40 is inserted in the underground tank 12 as the container 40 contains the oil stored in the tank 12, and has a string 45 which is locked to the upper end of the container 40 and to a weight measuring part 44a of the weigher 44. The arithmetic unit 46 calculates an amount of generation of oil vapor resulting from evaporation from the liquid level 34 on the basis of a difference ▵W between the total weight W1 of the measuring container 40 before the insertion in the tank 12 and the total weight W2 of the same after the takeout from the tank 12, both weights being measured with the weigher 44, and puts the amount of generation of the oil vapor on a display. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an in-tank liquid evaporation amount measuring method and apparatus, and more particularly to an in-tank liquid evaporation amount measuring method and apparatus for accurately measuring the evaporation amount of liquid stored in a tank.

  For example, in a service station that supplies oil such as gasoline to a vehicle, the remaining amount is managed by measuring the amount of the underground tank in which the oil is stored with a liquid level gauge. In order to grasp this, it is desired to be able to measure how much the oil liquid has evaporated during the next unloading after the oil liquid delivered by the tank truck is unloaded.

Conventionally, since there is no measuring means for measuring the amount of oil liquid evaporated in the underground tank, it is not known what measurement method is better. For example, the concentration of oil vapor (vapor) in the gas phase region of the tank A method of providing a concentration sensor for measurement, a method of providing a flow meter for measuring the discharge amount of oil vapor at the atmosphere opening of a vent pipe connected to a tank, and the like have been studied (for example, see Patent Document 1).
JP 2001-221678 A

  However, in the method of providing a concentration sensor for measuring the concentration of oil vapor (vapor) in the gas phase region of the underground tank as described above, the concentration of oil vapor (vapor) varies depending on the location of the gas phase region of the underground tank, Alternatively, when the atmosphere is introduced from a vent pipe connected to the underground tank, the concentration changes, which causes a problem that it is difficult to accurately measure the concentration.

  In addition, in the method of measuring the amount of oil vapor discharged to the air opening of the vent pipe connected to the underground tank, the oil vapor generated in the underground tank is released into the atmosphere or through the vent pipe. Since the atmosphere is introduced into the underground tank, the flow rate of the oil vapor is not always measured, so that it is difficult to accurately measure only the oil vapor. Furthermore, the amount of oil vapor varies depending on environmental conditions such as liquid temperature, atmospheric pressure, and humidity, and it is necessary to measure it over time. Therefore, generally used flow meters accurately measure oil vapor. I can't.

  Therefore, an object of the present invention is to provide a method and apparatus for measuring the amount of liquid evaporation in a tank that solves the above problems.

  The invention according to claim 1 is a first step of injecting a liquid stored in a tank into a measurement container having an upper end opening, a second step of measuring the amount of liquid injected into the measurement container, and the measurement A third step of inserting the measurement container so that the upper end opening of the container is located above the liquid level in the tank; and a predetermined time has elapsed and the measurement container is removed from the tank and the remaining in the measurement container And a fourth step of measuring the amount, and a fifth step of determining the amount of liquid evaporation in the tank from the difference between the measurement value before insertion of the measurement container and the measurement value after removal of the measurement container.

  The invention described in claim 2 is characterized in that the liquid stored in the tank is an oil liquid.

  The invention according to claim 3 is the method for measuring the amount of liquid evaporation in the tank according to claim 1, wherein in the third step, the measuring container moves up and down according to the fluctuation of the liquid level in the tank. It has the process of maintaining the state which the upper end opening of the measurement container was located above the liquid level in the said tank.

  Invention of Claim 4 is the liquid evaporation amount measuring method in the tank of said Claim 1, Comprising: The time-dependent change of the temperature in the said tank is measured at the said 5th process, The temperature change in the said tank The amount of reduction of the liquid in the measurement container corresponding to is obtained.

  The invention according to claim 5 has an upper end opening, a bottomed portion is formed heavy, a measuring container into which liquid stored in a tank is injected and inserted into the tank, and an upper end opening of the measuring container Operating means for operating the measurement container so that is positioned above the liquid level in the tank, the amount of the liquid in the measurement container before being inserted into the tank, and the measurement container inserted into the tank for a predetermined time And measuring means for measuring the amount of liquid in the tank, and calculating means for calculating the amount of liquid evaporation in the tank from the difference between the measured value before insertion of the measuring container and the measured value after removal of the measuring container. To do.

  The invention described in claim 6 is characterized in that the measuring container is formed in a cylindrical shape from a material having high thermal conductivity.

  According to a seventh aspect of the present invention, the actuating means holds the measurement container so that buoyancy is imparted to the measurement container and the upper end opening of the measurement container is positioned above the liquid level in the tank. Features.

  According to an eighth aspect of the present invention, the actuating means moves the measurement container up and down so that the upper end opening is positioned above the liquid level in the tank according to the liquid level height position in the tank. Features.

The invention according to claim 9 measures the weight of the measurement container before being inserted into the tank and the weight of the measurement container inserted into the tank for a predetermined time,
The calculating means calculates a liquid evaporation amount in the tank based on a difference between a weight of the measuring container before being inserted into the tank and a weight of the measuring container inserted into the tank for a predetermined time. To do.

The invention according to claim 10 measures the liquid level position of the measurement container before being inserted into the tank and the liquid level position of the measurement container inserted into the tank for a predetermined time,
The calculation means calculates a liquid evaporation amount in the tank based on a difference between a liquid level position of the measurement container before being inserted into the tank and a liquid level position of the measurement container inserted into the tank for a predetermined time. It is characterized by that.

  According to the present invention, the amount of liquid injected into the measuring container is measured, and then the measuring container is inserted so that the upper end opening of the measuring container is located above the liquid level in the tank, and then for a predetermined time. After that, the measurement container is removed from the tank, the remaining amount in the measurement container is measured, and the difference between the amount before insertion of the measurement container and the amount after removal of the measurement container is obtained to accurately determine the evaporation amount in the measurement container. The evaporation amount of the entire tank can be obtained from the measured evaporation amount.

  In addition, even if the liquid level in the tank fluctuates, the measurement container can follow the liquid level and the conditions in the tank and the measurement container can be kept the same. The amount of oil vapor generated in the tank and the amount of oil vapor generated in the measurement vessel are proportional to the liquid surface area ratio, and the evaporation of the entire tank is based on this area ratio. The amount can be accurately determined.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a liquid evaporation amount measuring apparatus in a tank according to the present invention.
As shown in FIG. 1, the in-tank liquid evaporation amount measuring device 10 is configured to measure, for example, oil vapor generated in an underground tank 12 of a liquid supply station.

  At the liquid supply station, there is installed a measuring device 14 that pumps up the oil liquid in the underground tank 12 and supplies it to the fuel tank of the vehicle, and the underground tank 12 is buried underground. Further, the underground tank 12 is connected to a vent pipe line 16 whose upper end communicates with the atmosphere.

  Furthermore, the upper part of the underground tank 12 is communicated with the ground via a manhole 18, and the manhole 18 is unloaded from a detection hole 20 for examining the inside of the underground tank 12 and a tank truck (not shown). An unloading port (not shown) to which an unloading hose is connected is provided.

  Inside the underground tank 12, temperature sensors 22 to 24 for measuring the liquid temperature are provided at different heights (depths), and a liquid level gauge 28 for detecting the liquid level height position is provided. A temperature sensor 26 for measuring the outside air temperature is also provided on the ground. Further, the interior of the underground tank 12 is divided into a gas phase region 30 and a liquid phase region 32. When unloading from a tank truck is performed, the liquid level 34 rises and the air and oil in the gas phase region 30 are discharged. Vapor is released into the atmosphere via the vent line 16.

  Further, when liquid supply is performed by the weighing machine 14, the liquid level 34 in the underground tank 12 is lowered and outside air is introduced into the underground tank 12 through the ventilation pipe 16.

  The in-tank liquid evaporation amount measuring apparatus 10 maintains the measurement container 40 inserted into the underground tank 12 from the detection hole 20 and the liquid level 41 of the measurement container 40 at substantially the same height as the liquid level 34 of the underground tank 12. As described above, the float (actuating means) 42 for imparting buoyancy to the measurement container 40, the scale (measurement means) 44 for measuring the weight of the measurement container 40, and the weight measured by the scale 44 are stored in the underground tank 12. And an arithmetic device 46 for calculating the amount of oil vapor generated in the stored oil liquid.

  The measuring container 40 is inserted into the underground tank 12 in a state where the oil liquid stored in the underground tank 12 is injected therein, and the string 45 locked at the upper end is locked to the load measuring unit 44 a of the scale 44. ing. The string 45 is in a relaxed state except when the weight of the measurement container 40 is measured.

FIG. 2 is a longitudinal sectional view showing the measurement container 40 in an enlarged manner. FIG. 3 is a perspective view showing the configuration of the float 42.
As shown in FIG. 2, the measurement container 40 is formed of a cylindrical body formed in a bottomed cylindrical shape and has an upper opening 40 a that communicates with the gas phase region 30. The mounting position of the float 42 is adjusted so that the height position H from the liquid level 34 of the underground tank 12 to the upper opening 40a maintains a predetermined value set in advance.

  The measuring container 40 has a center of gravity on the bottom side because the weight 48 is fixed to the bottom, and is maintained in a vertical state by the float 42 and the weight 48. Furthermore, the measurement container 40 is light and thin, and has a high thermal conductivity (for example, copper, iron, aluminum, etc.) so that the oil injected into the inside is at the same temperature as the oil in the underground tank 12. It is formed by.

  As shown in FIG. 3, the float 42 is made of, for example, a buoyancy imparting member such as a polystyrene foam, and is formed in an annular shape so as to be fitted to the outer periphery of the measurement container 40. In addition, since the float 42 is provided with a notch 50 penetrating in a radial direction in a part of the annular shape, the notch 50 is widened and fitted to the outer periphery of the measurement container 40, so that the measurement container 40 can be fitted. Hold the outer periphery.

  The upper part 42a of the float 42 is formed in a tapered shape inclined at a predetermined angle so that the oil liquid does not collect on the upper part, and a groove 42b into which the rubber ring 52 is fitted is provided on the outer periphery of the float 42. Then, after adjusting the mounting position of the float 42, the rubber ring 52 is fitted into the groove 54 of the float 42, so that the float 42 is brought to a predetermined height position on the outer periphery of the measuring container 40 by the tightening force of the rubber ring 52. Can be held.

Here, the procedure of the method for measuring the amount of liquid evaporation in the underground tank 12 using the above-described liquid evaporation amount measuring apparatus 10 in the tank will be described with reference to FIGS.
(Procedure 1) When the oil solution is unloaded from the tank truck to the underground tank 12, the worker injects the oil solution in the underground tank 12 into the measurement container 40 (see FIG. 4A).
(Procedure 2) Next, an operator inserts the measurement container 40 into the underground tank 12 from the detection hole 20 with the string 45 locked to the upper end of the measurement container 40. Then, the weight of the measurement container 40 is measured by the balance 44. At this time, the scale 44 measures the total weight W1 including the weight of the oil injected into the measurement container 40 and the weights of the measurement container 40, the float 42, and the weight 48 (see FIG. 4B).
(Procedure 3) Subsequently, the worker feeds the string 45 so that the measurement container 40 is immersed in the liquid level 34 of the underground tank 12 from the bottom. Then, the measurement container 40 is lowered in a vertical state until the float 42 fitted to the upper end of the measurement container 40 contacts the liquid level 34. And the detection hole 20 is obstruct | occluded with the lid | cover 54, and the string 45 is latched to the lid | cover 54, and the movement of the measurement container 40 is controlled (refer FIG.4 (C)).
(Procedure 4) The measurement container 40 inserted in the vertical state receives the buoyancy from the float 42 even if the liquid level 34 of the underground tank 12 is displaced by liquid supply to the vehicle, and the liquid level 41 of the measurement container 40 becomes underground. The height position is automatically adjusted so as to maintain the substantially same height position as the liquid level 34 of the tank 12. Actually, since the measuring container 40 and the weight 48 are heavy, the liquid level 41 of the measuring container 40 is lower than the liquid level 34 of the underground tank 12.
(Procedure 5) The state in which the measurement container 40 held in the vertical state is immersed in the liquid level 34 of the underground tank 12 is maintained for a predetermined period (for example, about 7 to 14 days) or until the next unloading. During this time, in the underground tank 12, the oil vapor evaporates from the liquid level 34, and the oil vapor evaporates also from the liquid level 41 of the measurement container 40. The amount of oil vapor generated varies depending on conditions such as liquid temperature, air temperature, atmospheric pressure, and humidity. Since the measurement container 40 is inserted into the underground tank 12, the amount of oil vapor generated in the underground tank 12 is as follows. And the amount of oil vapor generated in the measurement container 40 are under the same condition, a proportional relationship is established.
(Procedure 6) After the predetermined period has elapsed, for example, before unloading from the tank truck, the measurement container 40 is raised to a height position away from the liquid level 34 of the underground tank 12, and in that state, the measurement container 40 The total weight W2 is measured by the balance 44. At that time, in order to support the balance 44 on the upper part of the manhole 18, a pair of support plates 56 are horizontally mounted, and a string 45 is inserted between the pair of support plates 56 to be engaged with the load measuring portion 44a of the balance 44, and the measurement is performed. The lower end of the container 40 is suspended from the liquid level 34 (see FIG. 4D).
(Procedure 7) The arithmetic device 46 calculates | requires difference (DELTA) W = (W1-W2) of the total weight W1 before the said measurement container insertion measured by the balance 44, and the total weight W2 after taking out the measurement container. Then, this ΔW is multiplied by the area ratio S1 / S2 between the surface area S1 of the liquid surface 34 of the underground tank 12 and the surface area S2 of the liquid surface 41 of the measuring container 40, and the amount of generated oil vapor evaporated from the liquid surface 34 of the underground tank 12 Is displayed on a display (not shown).

  The arithmetic unit 46 measures the temporal change in the temperature of the underground tank 12 with the temperature sensors 22 to 24 and also measures the temporal change in the outside air temperature with the temperature sensor 26. A reduction amount of the oil liquid in the measurement container 40 below is calculated.

  In this way, the in-tank liquid evaporation measuring device 10 measures the amount (weight) of the liquid injected into the measuring container 40 using the balance 44, and then the upper end opening of the measuring container 40 is in the underground tank 12. The measurement container 40 is inserted so as to be positioned above the liquid level of the liquid, and after a predetermined time has elapsed (when unloading from the tank truck), the measurement container 40 is removed from the underground tank 12 and the remaining in the measurement container 40 is removed. By measuring the amount (weight) and obtaining the difference between the amount before insertion of the measurement container and the amount after removal of the measurement container, the amount of oil vapor generated in the measurement container 40 can be accurately measured, and this evaporation amount The oil vapor generation amount of the entire underground tank 12 can be obtained from the measured value.

  In addition, even when the liquid level in the underground tank 12 fluctuates, the measurement container 40 can follow the liquid level 34 and the conditions in the underground tank 12 and the measurement container 40 can be kept the same. Since it is possible to measure the amount of oil vapor generated while being inserted into the tank 12, the amount of oil vapor generated in the underground tank 12 and the amount of oil vapor generated in the measurement container 40 are proportional to the area ratio of the liquid level. Therefore, the amount of oil vapor generated in the entire underground tank 12 can be accurately obtained based on this area ratio.

FIG. 5 is a longitudinal sectional view showing Embodiment 2 of the tank liquid evaporation measuring apparatus. FIG. 6 is a perspective view showing the lifting mechanism of the second embodiment. In FIGS. 5 and 6, the same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.
As shown in FIG. 5, the in-tank liquid evaporation measuring device 60 includes a measuring container 40 inserted into the underground tank 12 from the detection hole 20, and a liquid surface 41 of the measuring container 40 is a liquid surface 34 of the underground tank 12. The lifting / lowering mechanism (actuating means) 62 for raising and lowering the measuring container 40 so as to maintain substantially the same height position, a scale (measuring means) 44 for measuring the weight of the measuring container 40, and the weight measured by the scale 44 And an arithmetic unit 46 for storing and calculating the amount of oil vapor generated in the oil liquid.

  As shown in FIG. 6, the elevating mechanism 62 includes a guide portion 64 that guides the elevation of the measurement container 40, a wire 66 that is locked to the upper end of the measurement container 40, a pulley 68 that winds the wire 66, and a pulley A stepping motor 70 that rotationally drives the motor 68, and a motor control unit 72 that controls the rotation direction and rotation angle of the rotation shaft of the stepping motor 70.

  As shown in FIG. 7, the guide portion 64 has a pair of guide members 74 and 75 formed so as to face the outer periphery of the measurement container 40 in a vertical state, and between the pair of guide members 74 and 75. Are formed with openings 76 and 77 extending in the vertical direction for the oil liquid to flow therethrough.

  The measurement container 40 inserted into the guide portion 64 is guided by the inner walls of the guide members 74 and 75 so that the outer periphery thereof can be moved up and down, and the measurement container 40 flows into the guide portion 64 through the openings 76 and 77. It is kept in a state immersed in oil.

  The motor control unit 72 calculates the rotation direction and rotation angle of the stepping motor 70 according to the liquid level detection signal from the liquid level gauge 28 that detects the liquid level position inside the underground tank 12, and rotates the pulley 68. By controlling the direction and the rotation angle, the measurement container 40 suspended from the wire 66 is raised and lowered so that the liquid level 41 of the measurement container 40 is maintained at substantially the same height as the liquid level 34 of the underground tank 12. The position is adjusted automatically.

  Since the measuring container 40 moves up and down in a vertical state while the rolling due to the lifting operation is suppressed by the guide members 74 and 75, the oil liquid stored in the underground tank 12 may jump and flow from the upper opening 40a. Is prevented.

  In this way, by controlling the rotation direction and rotation angle of the rotation shaft of the stepping motor 70, the liquid level 41 of the measurement container 40 is adjusted to substantially the same height position as the liquid level 34 of the underground tank 12, for example, Even when unloading from a tank truck, it is possible to continue measuring the amount of evaporation, and to measure the amount of oil vapor generated over a long period of time without affecting the operation of the liquid station.

  In this case, the liquid evaporation amount measuring device 60 in the tank measures the amount (weight) of the liquid injected into the measuring container 40 by locking the wire 66 to the load measuring unit 44a of the balance 44, and then the measuring container. The measurement container 40 is inserted so that the upper end opening of 40 is located above the liquid level in the underground tank 12, and then the wire 66 is removed from the pulley 68 after a predetermined time has elapsed (when unloading from the tank truck). The amount of oil vapor generated in the measuring container 40 is accurately measured by measuring the remaining amount (weight) of the measuring container 40 and determining the difference between the amount before insertion of the measuring container and the amount after removal of the measuring container. The amount of oil vapor generated in the entire underground tank 12 can be obtained from the measured evaporation amount.

FIG. 7 is a longitudinal sectional view showing Embodiment 3 of the in-tank liquid evaporation amount measuring apparatus. In FIG. 7, the same parts as those in the above embodiment are denoted by the same reference numerals and the description thereof is omitted.
As shown in FIG. 7, the liquid evaporation amount measuring device 80 in the tank is provided with a liquid level gauge 82 for measuring the liquid level of the liquid level 41 inside the measurement container 40. This level gauge 82 measures a change in liquid level (a decrease in liquid level) according to the evaporation amount of the oil injected into the measuring container 40.

  Then, the arithmetic unit 46 calculates the difference ΔH between the liquid level H1 (liquid level height) before insertion measured by the liquid level gauge 82 and the liquid level H2 (liquid level height) after taking out the measuring container after a predetermined time has elapsed. = (H1-H2) is obtained. Then, this ΔH is multiplied by the area ratio S1 / S2 between the surface area S1 of the liquid surface 34 of the underground tank 12 and the surface area S2 of the liquid surface 41 of the measuring container 40, and the amount of generated oil vapor evaporated from the liquid surface 34 of the underground tank 12 Is displayed on a display (not shown).

  In this manner, the amount of oil vapor generated in the measurement container 40 is measured by measuring the amount of change (ΔH) in the height position (liquid level) of the liquid level 41 of the measurement container 40, and based on this liquid level measurement value. It is possible to determine the amount of oil vapor generated from the liquid level 34 of the underground tank 12.

  In the above embodiment, a method for measuring the amount of oil vapor generated in an underground tank installed in a fuel supply station that supplies fuel such as gasoline to a fuel tank of a vehicle has been described. Of course, the present invention can also be applied to a leak inspection of an underground tank installed in the facility.

  In the above embodiment, the detection hole 20 is used to insert the measurement container 40. However, the present invention is not limited to this, and an opening for mounting the level gauge or an appropriate opening formed in the upper part of the tank is used. Needless to say, the measurement container 40 may be inserted.

It is a block diagram which shows one Example of the liquid evaporation amount measuring device in a tank which becomes this invention. It is a longitudinal cross-sectional view which expands and shows the measurement container. FIG. 3 is a perspective view showing the configuration of the float 42. 3 is a perspective view showing a configuration of a float 42. FIG. FIG. 4 is a process diagram for explaining the procedure of the method for measuring the amount of liquid evaporation in the underground tank 12. It is a longitudinal cross-sectional view which shows Example 2 of the liquid evaporation amount measuring apparatus in a tank. It is a perspective view which shows the raising / lowering mechanism of Example 2. FIG. It is a longitudinal cross-sectional view which shows Example 3 of the liquid evaporation amount measuring apparatus in a tank.

Explanation of symbols

10, 60, 80 In-tank liquid evaporation measuring device 12 Underground tank 14 Weighing machine 18 Manhole 20 Detection holes 22-24, 26 Temperature sensor 30 Gas phase region 32 Liquid phase region 34, 41 Liquid level 40 Measuring container 42 Float 44 Scale 46 arithmetic unit 48 weight 52 rubber ring 62 lifting mechanism 64 guide part 66 wire 70 stepping motor 72 motor control part 74, 75 guide member 82 level gauge

Claims (10)

A first step of injecting a liquid stored in a tank into a measurement container having an upper end opening;
A second step of measuring the amount of liquid injected into the measurement container;
A third step of inserting the measurement container so that the upper end opening of the measurement container is positioned above the liquid level in the tank;
A fourth step of taking out the measurement container from the tank after a predetermined time and measuring the remaining amount in the measurement container;
A fifth step of determining the amount of liquid evaporation in the tank from the difference between the measurement value before insertion of the measurement container and the measurement value after removal of the measurement container;
A method for measuring a liquid evaporation amount in a tank, comprising:   The method for measuring a liquid evaporation amount in a tank according to claim 1, wherein the liquid stored in the tank is an oil liquid. The method for measuring a liquid evaporation amount in a tank according to claim 1,
In the third step, the measurement container moves up and down according to a change in the liquid level in the tank, and the upper end opening of the measurement container is maintained above the liquid level in the tank. A method for measuring the amount of liquid evaporation in the tank. The method for measuring a liquid evaporation amount in a tank according to claim 1,
A method for measuring the amount of liquid evaporation in a tank, wherein a time-dependent change in the temperature in the tank is measured in the fifth step, and a decrease amount of the liquid in the measurement container corresponding to the temperature change in the tank is obtained. . A measurement container having an upper end opening, a bottomed portion formed heavy, and a liquid stored in a tank is injected into the tank,
An operating means for operating the measurement container so that the upper end opening of the measurement container is positioned above the liquid level in the tank;
Measuring means for measuring the amount of liquid in the measuring container before being inserted into the tank and the amount of liquid in the measuring container inserted into the tank for a predetermined time;
Calculation means for calculating the amount of liquid evaporation in the tank from the difference between the measurement value before insertion of the measurement container and the measurement value after removal of the measurement container;
An in-tank liquid evaporation amount measuring device comprising:   The in-tank liquid evaporation measuring device according to claim 5, wherein the measuring container is formed in a cylindrical shape from a material having high thermal conductivity.   The said actuating means gives the said measurement container buoyancy, and hold | maintains the said measurement container so that the upper end opening of the said measurement container may be located above the liquid level in the said tank. For measuring the amount of liquid evaporation in the tank.   The said operation | movement means raises / lowers the said measurement container so that the said upper end opening may be located above the liquid level in the said tank according to the liquid level height position in the said tank. For measuring the amount of liquid evaporation in the tank. The measuring means measures the weight of the measurement container before being inserted into the tank and the weight of the measurement container inserted into the tank for a predetermined time,
The calculating means calculates a liquid evaporation amount in the tank based on a difference between a weight of the measuring container before being inserted into the tank and a weight of the measuring container inserted into the tank for a predetermined time. The in-tank liquid evaporation amount measuring apparatus according to claim 5. The measuring means measures the liquid level position of the measurement container before being inserted into the tank and the liquid level position of the measurement container inserted into the tank for a predetermined time,
The calculation means calculates a liquid evaporation amount in the tank based on a difference between the liquid level position of the measurement container before being inserted into the tank and the liquid level position of the measurement container inserted into the tank for a predetermined time. The in-tank liquid evaporation measuring device according to claim 5.

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