JP2009109238A - Portable liquid detection unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a portable liquid detection unit capable of easily displaying the remaining quantity of a liquid and its consumption period on the basis of the position of a liquid level detected through the use of an ultrasonic beam for measurement by moving along an external surface of a side wall part of a container and excellent in convenience. <P>SOLUTION: When a main switch 105a is at a measuring position, a date display part 104a; a cylinder display part 104b; and a level display part 104c are sequentially selected by pressing a selector switch 105c. Input content is altered in an increasing direction or in a decreasing direction by pressing an input switch 105d. The input content is verified and stored by pressing a verification switch 105e. When the main switch 105a is at a history position, level measurement information to be displayed, on the date display part 104a; the cylinder display part 104b; and the level display part 104c, is selected by pressing the selector switch 105c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a portable liquid detection unit.

  Conventionally, as an example of a so-called ultrasonic level meter (liquid level meter) that detects the liquid level from the outside of a tank or cylinder (container) in a non-contact manner, an ultrasonic wave transmitted through the container wall. Is known to detect the presence or absence of liquid by detecting the reflected wave that passes through the container wall and returns to the transducer. (See, for example, Patent Documents 1, 2, and 3).

Japanese Patent Laid-Open No. 2006-183685 Japanese Patent No. 3081031 JP 2001-304940 A

  In these technologies, the liquid level of liquefied gas, etc. is measured by an ultrasonic level meter, and the liquid level position and the remaining volume are output, so that the consumption time (that is, the container replacement time or liquid filling time) Can be notified. However, in order to notify the consumption time, the remaining amount information obtained by the ultrasonic level meter fixed to the bottom wall is transmitted to the management center through the public network (in the case of Patent Document 1), or a plurality of sets on the side wall. There is a possibility that a liquid level position is detected by fixing an ultrasonic level meter (in the case of Patent Document 2), a large notification system is required, and the cost is increased. Moreover, although the ultrasonic level meter described in Patent Document 3 is configured as a handy type that can move in the vertical direction along the side wall, a communication means and a notification system for transmitting the detection result to the management center are constructed. There is a need. In particular, in the techniques described in these, it is difficult to know the consumption time of the cylinder etc. on the spot where the liquid level of the liquefied gas or the like is measured with an ultrasonic level meter, and by acquiring information from the notification system anew The operation may be complicated.

  The problem of the present invention is that it is possible to easily display the remaining volume of liquid and the time of consumption based on the liquid surface position detected by using the ultrasonic beam for measurement by moving along the outer surface of the side wall of the container. An object of the present invention is to provide a portable liquid detection unit excellent in performance.

Means for Solving the Problems and Effects of the Invention

In order to solve the above problems, the portable liquid detection unit of the present invention is:
A portable liquid detection unit used as a system to be measured with a container containing liquid, being movable along the outer surface of the side wall of the container,
An ultrasonic beam for measurement for exciting the system under measurement is output in the thickness direction of the container, and an ultrasonic wave capable of receiving reverberant ultrasonic waves from the system under measurement and reflected ultrasonic waves in the system under measurement is also available. An ultrasonic transducer including an acoustic wave transmitting / receiving surface, and a liquid level position detecting means capable of detecting the liquid level position of the liquid from the outside of the container;
And a remaining amount display means for displaying the remaining capacity of the liquid contained in the container at a liquid level position level based on the liquid level position detected by the liquid level position detecting means.

  In such a portable liquid detection unit, the remaining volume of the liquid is determined based on the liquid surface position detected by the measurement ultrasonic beam of the liquid surface position detection means by moving along the outer surface of the side wall of the container. Remaining amount display means (for example, a level display by numbers of a 7 segment display system) for displaying at the liquid level position level is provided. Therefore, it is possible to easily display the remaining liquid capacity and the consumption time (that is, the container replacement time and the liquid filling time), and it is possible to configure a portable liquid detection unit having excellent portability and convenience. In particular, it is easy to know the consumption time of the liquefied gas cylinder etc. on the spot where the liquid surface position is measured by the measuring ultrasonic beam, and the portable liquid detection unit can be used as a portable meter such as a cylinder.

Specifically, level input means for artificially inputting the liquid level position level,
A date input means for artificially inputting the date on which the liquid level position level is detected;
Storage means for associating the inputted liquid level position level and date and storing it as level measurement information;
Predicting means for predicting the consumption time when the remaining volume of the liquid becomes a predetermined amount or less from a plurality of level measurement information stored in the storage means can be provided.

  In this way, it is easy to know the consumption time of the container on the spot when the liquid level position is measured, and as a portable liquid detection unit excellent in portability and convenience, it is used as a portable meter such as a liquefied gas cylinder. Can also be suitably used. In particular, by inputting the liquid level position level and the detected date, the user can easily manage the liquid consumption time with a simple configuration.

  For example, an approximate expression is set between the liquid level position level and the date of meter reading from a plurality of level measurement information (past meter reading data), and the remaining capacity of the current liquid becomes zero based on the approximate expression. It is possible to predict (guess) the consumption time when the liquid needs to be filled. Note that the predicted value of the consumption time can be displayed by the remaining amount display means.

Moreover, in order to solve the said subject, the portable liquid detection unit of this invention is the following.
A portable liquid detection unit used as a system to be measured with a container containing liquid, being movable along the outer surface of the side wall of the container,
An ultrasonic beam for measurement for exciting the system under measurement is output in the thickness direction of the container, and an ultrasonic wave capable of receiving reverberant ultrasonic waves from the system under measurement and reflected ultrasonic waves in the system under measurement is also available. An ultrasonic transducer including an acoustic wave transmitting / receiving surface, and a liquid level position detecting means capable of detecting the liquid level position of the liquid from the outside of the container;
A moving distance measuring means for measuring a moving distance in the vertical direction on the outer surface of the side wall portion starting from a measurement start position determined on the outer surface of the side wall portion of the container;
Based on the liquid level position detected by the liquid level position detecting means and the moving distance measured by the moving distance measuring means, the remaining amount for displaying the remaining capacity of the liquid stored in the container as the liquid level position level. And a display means.

  In such a portable liquid detection unit, the liquid surface position detected by the measurement ultrasonic beam of the liquid surface position detection means and the movement distance measurement means are measured by moving along the outer surface of the side wall of the container. A remaining amount display means for displaying the remaining volume of the liquid as the liquid level position level based on the travel distance is provided. Accordingly, it is possible to easily display the remaining liquid volume and the consumption time (that is, the container replacement time and the liquid filling time), and it is possible to configure a portable liquid detection unit that is highly convenient. In particular, the liquid level position is measured by the ultrasonic beam for measurement and the moving distance in the vertical direction is measured by the moving distance measuring means. With the improvement of the measurement accuracy of the remaining liquid volume (liquid level position level), The prediction accuracy of the consumption time of liquefied gas cylinders etc. is also improved.

  Also in this case, storage means for storing the liquid surface position level detected by the liquid surface position detection means and the movement distance measurement means in association with the date when the liquid surface position level is detected is stored as level measurement information. be able to. As described above, by storing the level measurement information (the liquid surface position level and the detected date) in the storage means, it becomes easy to predict and manage the consumption time when the container needs to be replaced or filled with the liquid.

  Furthermore, a predicting means for predicting a consumption time when the remaining volume of the liquid becomes a predetermined amount or less from a plurality of level measurement information stored in the storage means can be provided. By providing such a predicting means, in a plurality of level measurement information, the liquid consumption time can be accurately determined from an approximate expression derived from the correlation between the liquid level position level data and the detected date data. Can be predicted. In this case as well, the predicted value of the consumption time can be displayed by the remaining amount display means.

Specifically, the moving distance measuring means detects the relative rotation angle of the rotating roller that rotates in contact with the outer surface of the side wall of the container,
The liquid surface position detecting means detects the liquid surface position when the ultrasonic transducer receives reflected ultrasonic waves or reverberant ultrasonic waves,
In some cases, the detection of the relative rotation angle of the rotating roller and the detection of the liquid surface position are performed simultaneously.

  In such a case, the moving distance of the liquid detection unit can be measured with high accuracy by detecting the relative rotation angle of the rotating roller, and the liquid level position can be detected with high accuracy by the ultrasonic liquid level position detecting means. it can. Moreover, by simultaneously detecting (for example, synchronizing) detection of the relative rotation angle of the rotating roller and detection of the liquid surface position, the liquid surface position level can be accurately detected in a short time. In order to detect the relative rotation angle of the rotating roller, a rotary encoder, a rotary potentiometer, or the like can be used as the moving distance measuring means.

  For example, the moving distance measuring means has a rotating direction detecting means for detecting the rotating direction of the rotating roller, and the detection of the liquid level shifts from the absence of liquid to the presence of liquid depending on the rotation direction detected by the rotating direction detecting means. It can be discriminated whether it is performed in a state where it is performed or in a state where it is shifted from the presence of liquid to the absence of liquid. Thus, if the rotation direction of the rotation roller is detected by the rotation direction detection means, the movement distance measurement means is moved from the upper (no liquid) to the lower (liquid) when measuring the movement distance on the outer surface of the side wall of the container. The detection error of the liquid surface position level can be suppressed by discriminating between the case of moving to (with) and the case of moving from down (with liquid) to up (without liquid).

  Alternatively, when detection of the liquid surface position is determined by reflected ultrasonic information or reverberant ultrasonic information when transitioning from no liquid to liquid presence, from the measurement start position to the liquid surface position at the time of measurement, The liquid surface position detecting means can stop the output of the measurement ultrasonic beam from the ultrasonic transducer. In this way, since it does not participate in the detection of the liquid surface position from the measurement start position to the liquid surface position at the time of measurement, the output of the ultrasonic beam for measurement from the liquid surface position detection means (ultrasonic transducer) is stopped. Therefore, it is possible to prevent erroneous detection of the liquid level position, suppress power consumption, and promote energy saving.

  On the other hand, when the detection of the liquid surface position is determined by the reflected ultrasonic information or the reverberant ultrasonic information when transitioning from the presence of the liquid to the absence of the liquid, the liquid surface position detecting means detects the ultrasonic wave after detecting the liquid surface position. The output of the ultrasonic beam for measurement from the transducer can be stopped. In this way, since detection of the liquid surface position is not involved after the detection of the liquid surface position, the output of the ultrasonic beam for measurement from the liquid surface position detecting means (ultrasonic transducer) is stopped, so that the liquid surface position is erroneously detected. Detection can be prevented and power consumption can be suppressed to save energy.

The moving distance measuring means measures the total stroke moving distance from the measurement start position defined on the outer surface of the side wall of the container to the end point in the vertical direction on the outer surface of the side wall, and measures the height of the container. At the same time, the liquid surface position is detected at the midway position of the entire travel distance,
The remaining amount display means can display the remaining liquid volume as the liquid surface position level in accordance with the total stroke moving distance and the moving distance to the liquid surface position.

  In this way, the moving distance measuring means can measure the moving distance of the entire stroke from the starting point to the ending point, and can simultaneously measure the moving distance to the liquid surface position. Therefore, if the ratio of the total travel distance (ie, the height of the container) and the distance traveled to the liquid surface position (ie, the height of the area without liquid or the area with liquid) is taken from one measurement result, Regardless of size, the current liquid level position (remaining liquid volume) in the container is immediately obtained.

  By the way, these portable liquid detection units can move along the outer surface of the side wall of the container, and the ultrasonic transducer can also receive reverberant ultrasonic waves from the measured system and reflected ultrasonic waves in the measured system. Accordingly, the liquid surface position detection means includes a side wall transmission inner surface reflection ultrasonic detection method (a method for detecting ultrasonic waves that are transmitted through the side wall of the container and reflected by the inner surface of the opposite container side wall) and a reverberation ultrasonic detection method (measured object). Any liquid detection unit (that is, an ultrasonic level meter (liquid level meter)) of a system that detects reverberant ultrasonic waves from the system) can be provided.

  For example, the container is a metal tank, and the ultrasonic transducer is movable in the vertical direction along the outer surface of the metal side wall of the metal tank, and outputs a measurement ultrasonic beam in the thickness direction of the metal side wall. Further, the present invention can be applied to any portable liquid detection unit of the side wall transmission inner surface reflection ultrasonic detection method and the reverberation ultrasonic detection method. In this case, the metal tank to be measured can be made of a material having a relatively small internal acoustic loss, such as steel. Further, the metal tank can be a fuel tank mounted on a vehicle, a ship or an aircraft (particularly an automobile). Liquids such as liquefied gas (liquefied petroleum gas (LPG), liquefied natural gas (LNG) and other fuel gas, liquefied carbon dioxide gas, liquefied ammonia gas, cylinders of liquid nitrogen, tanks, containers, etc. Can be).

Example 1
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external explanatory view showing an example of liquid level detection by the portable liquid detection unit of the present invention, and FIG. 2 is a cross-sectional explanatory view showing the inside of the container of FIG. A metal tank 10 (container) containing a liquid L made of liquefied petroleum gas (LPG) or liquefied natural gas (LNG) constitutes the system 200 to be measured. The metal tank 10 is made of steel, and the wall thickness of the side wall portion 10S is substantially uniform. Further, the wall thickness of the bottom surface portion 10B and the top surface portion 10U is substantially uniform. Moreover, the gas extraction part 11 incorporating the pressure control valve is formed in the upper center of the top surface part 10U. The ultrasonic level meter 100 (portable liquid detection unit) can detect the presence or absence of the liquid L or the position LV of the liquid surface (liquid surface) from the outside of the metal tank 10 in a non-contact manner.

  The ultrasonic level meter 100 is attached to the outer wall surface 10a of the tank side wall 10S in a form pressed against the metal tank 10 (measuring system 200) containing the liquid L. Therefore, a fixed holding force (generally a holding force by a magnet) F acts toward the metal tank 10 in the attached state (see FIG. 2). The ultrasonic level meter 100 corresponds to a specific liquid level position LV (liquid level) that is a detection target in the metal tank 10 by the holding force F with respect to the wall outer surface 10a of the side wall 10S of the metal tank 10. When pressed by the liquid detection position, it is possible to detect the presence or absence of the liquid L at each liquid detection position, that is, whether or not the liquid L has reached the liquid surface position LV. In the present embodiment, the ultrasonic level meter 100 is configured to detect the ultrasonic wave transmitted through the side wall portion 10S of the metal tank 10 and reflected from the inner surface of the opposite side wall by the side wall transmitted inner surface reflected ultrasonic detection method. The liquid information (liquid level position LV) in the inside can be measured from the outside of the metal tank 10.

  In addition, the ultrasonic level meter 100 can detect the liquid level position LV by moving in the vertical direction along the wall outer surface 10a of the side wall 10S of the metal tank 10. On the wall outer surface 10a, in order to facilitate measurement of the liquid level position LV, the lowest liquid level LV0 (that is, the remaining capacity of the liquid L is zero) and the highest liquid level LV10 (that is, the liquid L The liquid level LV0 to LV10 (liquid level position level) divided into 10 equal parts are marked with scales (scales). Accordingly, by reading and inputting the position of the ultrasonic level meter 100 when the liquid level position LV is detected with the marks of the liquid level LV0 to LV10, the remaining volume of the liquid L (for example, the liquid level LV6) is liquid. Notification can be made by the surface detection display unit 104d and the speaker 106 (see FIG. 4). However, when the liquid level position LV is detected, if the ultrasonic level meter 100 is located in the middle of the scales of the liquid level LV0 to LV10, replenishment and replacement can be performed with a margin. It is desirable to read and input the lower scale. When the ultrasonic level meter 100 is moved from top to bottom along the wall outer surface 10a, the highest liquid level LV10 is the starting point of movement (measurement start position), and the lowest liquid level LV0 is the end point of movement (end of measurement). The total travel distance H from LV10 to LV0 corresponds to the height of the metal tank 10.

  FIG. 3 is a schematic diagram showing a configuration example of the portable liquid detection unit (ultrasonic level meter) together with its electrical configuration. The ultrasonic level meter 100 includes a case body 3 made of a resin or the like that can be held by a user's hand, and a cylindrical ultrasonic transducer 1 (ultrasonic output unit; reflected ultrasonic detection unit; The liquid level position detecting means is fitted (contained and disposed). The front end surface of the ultrasonic transducer 1 serving as the ultrasonic transmission surface 1a (ultrasonic emission surface) is located in the opening formed at the front end of the case body 3, and is in close contact with the ultrasonic transmission surface 1a. A cylindrical acoustic impedance matching layer 2 having a diameter slightly smaller than that of the sonic transducer 1 is attached.

  The acoustic impedance matching layer 2 has an acoustic impedance intermediate between the ultrasonic transducer 1 (piezoelectric ceramic) and the tank side wall 10S (steel) (preferably the geometric average value of both). Further, the front end surface 2a of the acoustic impedance matching layer 2 opposite to the close contact side with the ultrasonic transmission surface 1a is exposed to the outside of the case body 3, and the outer wall surface 10a of the side wall portion 10S of the metal tank 10 is exposed. The container contact surface which contacts is comprised. The acoustic impedance matching layer 2 is a flexible elastic material (for example, silicone resin) so that when the front end surface 2a (container contact surface) is pressed against the tank side wall portion 10S, the acoustic impedance matching layer 2 can be deformed following and closely adhered to the outer wall surface 10a. It is composed of.

  The ultrasonic transducer 1 outputs to the signal processing circuit 103 an electric signal (reception signal) by receiving an ultrasonic wave transmission function of transmitting an ultrasonic beam for measurement SW by applying a driving voltage from the driving circuit 101 and receiving a reflected ultrasonic wave. And an ultrasonic reception function (reflection ultrasonic detection function). Specifically, the piezoelectric ceramic diaphragm 1v polarized in the plate thickness direction, and electrode pairs 1e and 1e formed to face each other with the piezoelectric ceramic diaphragm 1v sandwiched between the main surfaces of the piezoelectric ceramic diaphragm 1v. With. The electrode pairs 1e and 1e serve as drive electrodes to which a drive voltage for ultrasonically vibrating the piezoelectric ceramic diaphragm 1v is applied during transmission of the measurement ultrasonic beam SW, and the piezoelectric ceramic diaphragm when receiving reflected ultrasonic waves. It becomes an output electrode that outputs an electrical signal accompanying 1v vibration. The connection between the electrode pair 1e, 1e and the driving circuit 101 and the signal processing circuit 103 is switched by a changeover switch 101s.

  The drive circuit 101 amplifies the output of the oscillation circuit (here, VCO (Voltage Controlled Oscillator)) 101b having a variable output frequency and the oscillation circuit 101b, and outputs the amplified output to the piezoelectric ceramic diaphragm 1v. A main circuit (amplifier) 101a. The output frequency of the oscillation circuit 101b is changed according to the frequency instruction voltage input from the frequency setting unit 102.

  The drive circuit 101, the changeover switch 101s, the frequency setting unit 102, and the signal processing circuit 103 are connected to a microcomputer 107 (liquid level detection control means) that controls these operation sequences. An input unit 105 and a display unit 104 are also connected to the microcomputer 107. The input unit 105 includes a push button switch and a keyboard, and is used for a liquid detection start trigger operation and a frequency setting process. Further, the display unit 104 visually outputs the detection determination result of the presence / absence of a liquid, and is configured as an LED lighting unit, for example. Furthermore, the speaker 106 acoustically outputs a detection determination result of the presence or absence of liquid.

  FIG. 4 is an explanatory diagram illustrating a configuration example of an input unit and a display unit of a portable liquid detection unit (ultrasonic level meter). The input unit 105 artificially inputs the date when the liquid level LV0 to LV10 is detected, and the cylinder input for artificially inputting the cylinder size (for example, L, M, S size) of the metal tank 10 Means and level input means for artificially inputting the liquid level LV0 to LV10.

  Specifically, the input unit 105 includes a four-position switching type main switch 105a, a push button type measurement start / end switch 105b, a push button type selection switch 105c, and a pressing direction switching type input switch 105d. And a push button type confirmation switch 105e.

  The main switch 105a detects the liquid level LV0 to LV10 by the ultrasonic transducer 1 on one side (for example, the right side) across the “off” position where all operations are stopped, and measures the level together with the detected date and cylinder size. A “measurement” position is provided for storage as information. On the other side (for example, the left side) across the “off” position, the “history” position where the level measurement information detected in the past is displayed on the display unit 104, and the remaining volume of the liquid L from the plurality of level measurement information is the lowest A “prediction” position is provided for predicting the consumption time (for example, the replacement time of the metal tank 10 or the filling time of the liquid L) at which the liquid level LV0 is reached. When the main switch 105a is in the “measurement” position, the measurement start / end switch 105b starts to detect the liquid level LV0 to LV10 when the main switch 105a is in the “measurement” position, and is pressed again after detecting the liquid level LV0 to LV10. Then, the detection of the liquid level LV0 to LV10 is finished.

  When the main switch 105a is in the “measurement” position, the date display unit 104a, the cylinder display unit 104b, and the level display unit 104c are sequentially selected by pressing the selection switch 105c, and the input content is increased or decreased by pressing the input switch 105d. The input content is confirmed and stored by pressing the confirmation switch 105e. When the main switch 105a is in the “history” position, the level measurement information to be displayed on the date display unit 104a, the cylinder display unit 104b, and the level display unit 104c is selected by pressing the selection switch 105c.

  The display unit 104 includes a date display unit 104a that displays a 6-digit LED for the year, month, and day using segments or dots, a cylinder display unit 104b that displays a single-digit LED for the cylinder sizes L, M, and S using segments or dots, and a liquid level. It includes a level display unit 104c that displays 2-digit LEDs of LV0 to LV10 using segments or dots, and a liquid level detection display unit 104d that displays the presence / absence of liquid level detection with one LED.

  Next, FIG. 5 is a block diagram showing an electrical configuration of the input unit and the display unit of the portable liquid detection unit (ultrasonic level meter). The microcomputer 107 of the ultrasonic level meter 100 includes a CPU (Central Processing Unit) 107a (prediction means) that is an arithmetic unit, a ROM (Read Only Memory) 107b that is a read-only storage device for storing programs, a work area, and various counters. Are provided with a RAM (Random Access Memory) 107c (storage means) which is a readable / writable storage device, and an input / output (I / O) 107d which is an input / output interface. ) Are connected to each other.

  Operation signals from the main switch 105a, the measurement start / end switch 105b, the selection switch 105c, the input switch 105d, and the confirmation switch 105e are input to the microcomputer 107, respectively. A liquid level detection signal from the ultrasonic transducer 1 is also input to the microcomputer 107.

  The microcomputer 107 drives and controls the LEDs of the date display unit 104a, the cylinder display unit 104b, and the level display unit 104c to display level measurement information. Further, the microcomputer 107 drives and controls the LED of the liquid level detection display unit 104d to display and output the presence / absence of liquid level detection, and drives and controls the speaker 106 to acoustically output the presence / absence of liquid level detection.

  Next, the flowchart of the liquid level detection process shown in FIG. 6 will be described with reference to a timing chart representing an example of ultrasonic wave transmission / reception by the ultrasonic transducer of FIG. First, the microcomputer 107 confirms whether or not the main switch 105a is set to “measurement” in S1. When the main switch 105a is set to “measurement” (YES in S1), a detection date (for example, “07.09.30”) is input in S2, and a cylinder size (for example, “L” in S3). ). Specifically, the input switch 105d is operated to display “07” in the left two digits (year column) of the date display unit 104a. After the selection switch 104c is pressed to shift to the middle two digits (month field), the input switch 105d is operated again to display “09”. After pressing the selection switch 104c to shift to the right two digits (day field), the input switch 105d is operated again to display “30”. Further, after the selection switch 104c is pressed to shift to the cylinder display portion 104b, the input switch 105d is operated again to display the cylinder size “L”.

  In S4, it is confirmed whether or not the measurement start is turned ON from the measurement start / end switch 105b of the input unit 105. When the measurement start is input ON (YES in S4), the changeover switch 101s switches to a drive connection state in which the ultrasonic transducer 1 is connected to the drive circuit 101 in S5, and the drive circuit 101 is set by the frequency setting unit 102. A drive AC voltage is applied to the ultrasonic transducer 1 at a frequency. Thereby, the ultrasonic beam SW for measurement is output from the ultrasonic transducer 1 to the tank side wall 10S at the measurement execution position, and this is acoustically excited. Next, in S <b> 6, the changeover switch 101 s switches to a signal detection connection state in which the ultrasonic transducer 1 is connected to the signal processing circuit 103. Then, after the acoustic excitation by the ultrasonic transducer 1 in S7, the reflected ultrasonic wave that is transmitted through the side wall 10S of the metal tank 10, reflected by the inner surface of the opposite side wall, and transmitted through the side wall 10S again within a predetermined time T. It is confirmed whether or not the ultrasonic transducer 1 has detected it. Note that the arrival time of reflected ultrasonic waves can be measured with a built-in clock of the microcomputer 107 or the like.

By the way, as shown in FIG. 2, the inside of the side wall part 10S of the metal tank 10 becomes a space | gap in the non-existing part (liquid absence part) of the liquid L, and the side wall part 10S of the side part 10S exists in the liquid L existence part (liquid presence part). The liquid L exists inside. In general, the density of the liquid serving as a medium in the metal tank 10 is extremely large (for example, about 10 ³ times) compared to the density of the gas. Therefore, as shown in FIG. 7, in the portion with liquid, it passes through the side wall 10 </ b> S of the metal tank 10, is reflected by the inner surface of the opposite side wall, passes through the side wall 10 </ b> S again, and is detected by the ultrasonic transducer 1. The However, in the no-liquid portion, the reflected wave is not detected by the ultrasonic transducer 1 due to the diffusion of the ultrasonic waves.

  Returning to FIG. 6, if the reflected ultrasonic wave is detected by the ultrasonic transducer 1 within the predetermined time T (YES in S7), an output with liquid is output by the liquid level detection display unit 104d of the display unit 104 and the speaker 106 in S8. (For example, the liquid level detection display unit 104d is turned on and the speaker 106 is a continuous sound). At this time, in S9, the detected liquid level is read from the scale (see FIG. 2) of the outer wall surface 10a of the side wall 10S (for example, the liquid level “LV6”) and input to the level display unit 104c. Specifically, after the selection switch 104c is pressed to shift to the level display unit 104c, the input switch 105d is operated to display the liquid level “6”. Further, in S10, level measurement information (date = “07.09.30”; cylinder size = “L”; liquid level = “6”) is collectively stored in the RAM 107c, and measurement start / end is used in S11. It is confirmed whether the measurement end is input ON from the switch 105b. If measurement end is input ON (YES in S11), the liquid level detection process is terminated. If measurement end is not input ON (NO in S11), an alarm is output in S12 (eg, liquid level detection display unit) 104d is lit red, and the speaker 106 is a warning sound).

  On the other hand, if no reflected ultrasonic wave is detected by the ultrasonic transducer 1 within the predetermined time T (NO in S7), the liquid level detection display unit 104d of the display unit 104 and the speaker 106 output no liquid at S13. (For example, the liquid level detection display unit 104d blinks and the speaker 106 is intermittent sound), and the liquid level detection process is terminated. When the main switch 105a is not set to “measurement” (NO in S1) and when the measurement start is not input ON (NO in S4), the liquid level detection process is finished as it is.

  Next, the flowchart of the information output process shown in FIG. 8 will be described with reference to the explanatory diagrams of FIGS. First, the microcomputer 107 confirms whether or not the main switch 105a is set to “history” in S21. When the main switch 105a is set to “history” (YES in S21), the latest level measurement information is displayed on the display unit 104 in S22. The level measurement information is stored in the RAM 107c in the order of measurement as shown in FIG. Therefore, here, the level measurement information stored in the RAM 107c in S11 (FIG. 6), that is, “07.09.30” in the date display unit 104a, “L” in the cylinder display unit 104b, and “6” in the level display unit 104c. Are respectively displayed (FIG. 11A).

  Next, in S23, it is confirmed whether the selection switch 105c is turned on. When the selection switch 105c is turned on (YES in S23), the previous level measurement information is displayed on the display unit 104 in S24. Here, the level measurement information stored in the second row in FIG. 9, that is, “07.09.22” is displayed on the date display unit 104a, “L” is displayed on the cylinder display unit 104b, and “7” is displayed on the level display unit 104c. (FIG. 11B). Then, in S25, it is confirmed whether or not the selection switch 105c has been continuously turned on for 2 seconds or more. If the selection switch 105c has been operated for 2 seconds or more (YES in S25), the information output process is terminated. However, if the selection switch 105c has not been operated (NO in S23) and if the selection switch 105c has been operated for less than 2 seconds (NO in S25), both return to S21.

  When the main switch 105a is not set to “history” (NO in S21), it is confirmed in S26 whether the main switch 105a is set to “prediction”. When the main switch 105 a is set to “prediction” (YES in S 26), consumption time prediction information is displayed on the display unit 104 in S 27. The consumption time prediction information is obtained from an approximate expression derived from the correlation between the liquid level data and the detected date data among the plurality of level measurement information (FIG. 9) stored in the RAM 107c. Is predicted (FIG. 10). Here, level measurement information represented by the intersection of the approximate straight line and the x-axis in FIG. 10, that is, “07.12.01” in the date display unit 104a, “L” in the cylinder display unit 104b, and “0” in the level display unit 104c. "Is displayed (FIG. 11 (c)). Further, in S28, the process waits until another switch operation is performed on the input unit 104. If there is a switch operation (YES in S28), the information output process is terminated.

  In this way, the remaining level of the liquid L and the consumption time (that is, the replacement time of the metal tank 10 and the filling time of the liquid L) can be easily displayed, and the ultrasonic level meter 100 excellent in portability and convenience is configured. can do. It is easy to know the consumption time of the liquefied gas cylinder etc. on the spot where the liquid level position LV is measured by the ultrasonic beam for measurement, and the ultrasonic level meter 100 can be used as a portable meter such as a cylinder. In addition, by inputting the liquid level LV0 to LV10 and the detected date, the user can easily manage the consumption time of the liquid L with a simple configuration.

  Specifically, an approximate expression is set between the liquid level LV0 to LV10 and the meter reading date from a plurality of level measurement information (past meter reading data), and the remaining capacity of the current liquid L is zero from the approximate expression. Thus, it becomes possible to predict (estimate) the consumption time when the replacement of the metal tank 10 or the filling of the liquid L is necessary.

(Example 2)
FIG. 12 is an explanatory view showing another configuration example of the input unit and display unit of the portable liquid detection unit (ultrasonic level meter), FIG. 13 is a schematic diagram showing the electrical configuration of the input unit and display unit, and FIG. FIG. 9 is a flowchart showing another example of the liquid level detection process. In the ultrasonic level meter 100 ′ of this embodiment, the wall portion starts from the measurement start position (for example, the highest liquid level LV10) determined on the wall portion outer surface 10a of the side wall portion 10S of the metal tank 10 (container). A rotary encoder 5 (moving distance measuring means) is provided to measure the moving distance in the vertical direction (for example, downward) on the outer surface 10a. The rotary encoder 5 detects the liquid level position LV by the ultrasonic transducer 1 (ultrasonic output unit; reflected ultrasonic wave detection unit; liquid level position detection means) and simultaneously detects (synchronizes with) the side wall portion 10S of the metal tank 10. The relative rotation angle of the rotating roller 4 rotating in contact with the wall outer surface 10a is detected.

  The rotary encoder 5 starts from the uppermost liquid level LV10 of the metal tank 10 and travels a full stroke moving distance H (up to the vertical end point (for example, the lowermost liquid level LV0) on the wall outer surface 10a of the side wall 10S. 2), the height of the metal tank 10 is measured to identify the size, and the liquid level position LV is detected at a midway position of the entire stroke movement distance H. Accordingly, the level display unit 104c (remaining amount display means) sets the remaining capacity of the liquid L to the liquid level LV0 to LV10 (liquid level position level) according to the total stroke moving distance H and the moving distance to the liquid level position LV. Display as.

  The microcomputer 107 ′ (liquid level detection control means) includes a built-in clock 107e, and automatically stores the detection date of the liquid level position LV by the ultrasonic transducer 1 in the level measurement information (see FIG. 11) of the RAM 107c (storage means). be able to. Therefore, the input unit 105 ′ does not require an input switch and a confirmation switch, and thus the configuration is further simplified.

  The flow chart of the liquid level detection process shown in FIG. 14 is an alternative to FIG. 6 (Example 1). First, the microcomputer 107 confirms whether or not the main switch 105a is set to “measurement” in S1. When the main switch 105a is set to “measurement” (YES in S1), it is checked in S4 whether the measurement start is input from the measurement start / end switch 105b of the input unit 105. When the measurement start is turned ON (YES in S4), the rotary encoder 4 starts measuring the movement distance from the starting point (the highest liquid level LV10) in S41. However, to save energy, the measurement ultrasonic beam SW is not yet output at this time.

  Further, in S42, it is confirmed that the previous liquid level LV0 to LV10 has been reached (YES in S42), and in S5, the changeover switch 101s switches to the drive connection state in which the ultrasonic transducer 1 is connected to the drive circuit 101, and the drive is performed. The circuit 101 applies a driving AC voltage to the ultrasonic transducer 1 at a frequency set by the frequency setting unit 102. Thereby, the ultrasonic beam SW for measurement is output from the ultrasonic transducer 1 to the tank side wall 10S at the measurement execution position, and this is acoustically excited. Next, in S <b> 6, the changeover switch 101 s switches to a signal detection connection state in which the ultrasonic transducer 1 is connected to the signal processing circuit 103. Then, after the acoustic excitation by the ultrasonic transducer 1 in S7, the reflected ultrasonic wave that is transmitted through the side wall 10S of the metal tank 10, reflected by the inner surface of the opposite side wall, and transmitted through the side wall 10S again within a predetermined time T. It is confirmed whether or not the ultrasonic transducer 1 has detected it. Note that the arrival time of reflected ultrasonic waves can be measured by the built-in clock 107e of the microcomputer 107.

  If the reflected ultrasonic wave is detected by the ultrasonic transducer 1 within the predetermined time T (YES in S7), the liquid presence output is made by the liquid level detection display unit 104d of the display unit 104 and the speaker 106 in S8 (for example, The liquid level detection display unit 104d is turned on and the speaker 106 is a continuous sound). In order to save energy, the subsequent output of the ultrasonic beam SW for measurement is stopped. At the same time, the liquid level LV0 to LV10 is measured from the output of the rotary encoder 4 at this time in S81 and stored in the RAM 107c (see FIG. 9). Further, in S82, it is confirmed that the rotary encoder 4 has reached the end point (the lowest liquid level LV0) (that is, the total travel distance H has been overcome) (YES in S82), and the cylinder size is determined in S83. The measurement date is stored in the RAM 107c (see FIG. 9), and the liquid level detection process ends.

  On the other hand, if no reflected ultrasonic wave is detected by the ultrasonic transducer 1 within the predetermined time T (NO in S7), the liquid level detection display unit 104d of the display unit 104 and the speaker 106 output no liquid at S13. (For example, the liquid level detection display unit 104d blinks and the speaker 106 is intermittent sound), and the liquid level detection process is terminated. When the main switch 105a is not set to “measurement” (NO in S1) and when the measurement start is not input ON (NO in S4), the liquid level detection process is finished as it is.

  Thus, since the liquid level position LV is measured by the ultrasonic beam SW for measurement and the moving distance in the vertical direction is measured by the rotary encoder 5, the measurement accuracy of the remaining capacity of the liquid L (liquid level LV0 to LV10) is measured. With this improvement, the prediction accuracy of the consumption time of liquefied gas cylinders and the like is also improved.

  In this embodiment, the detection of the liquid surface position LV is determined based on the reflected ultrasonic information when shifting from the absence of liquid to the presence of liquid (see FIG. 7). Since the output of the ultrasonic beam SW for measurement from the ultrasonic transducer 1 is stopped from the measurement start position (top liquid level LV10) to the liquid level LV at the time of measurement, the liquid level LV Can be prevented and power consumption can be suppressed to save energy.

  Further, the travel distance H of the entire stroke from the starting point (uppermost liquid level LV10) to the end point (lowermost liquid level LV0) is measured by the rotary encoder 5, and the moving distance to the liquid level position LV is also measured between them. Simultaneous measurement is possible. Therefore, if the ratio between the total stroke moving distance H (height of the metal tank 10) and the moving distance to the liquid surface position LV (height of the liquid-free region) is taken from one measurement result, Regardless of the size, the current liquid level LV0 to LV10 (remaining capacity of the liquid L) in the metal tank 10 is immediately obtained.

  In Example 2 (FIGS. 12 to 14), parts having the same functions as those in Example 1 (FIGS. 1 to 11) are denoted by the same reference numerals and description thereof is omitted.

  In the second embodiment, the moving direction of the ultrasonic level meter 100 ′ (the rotating direction of the rotating roller 4) can be identified by the reflected ultrasonic detection signal (see FIG. 7), but can also be identified by the rotary encoder 5. Is possible. Further, in the second embodiment, when the movement distance H of the entire stroke is not measured by the rotary encoder 5, the cylinder size may be input by the input switch 105d or the confirmation switch 105e as in the first embodiment.

Explanatory drawing which shows an example of the liquid level detection by the portable liquid detection unit of this invention. Cross-sectional explanatory drawing which shows the container inside of FIG. The schematic diagram which shows the structural example of the portable liquid detection unit of FIG. 1 with the electrical structure. Explanatory drawing which shows the structural example of the input part and display part of a portable liquid detection unit. The block diagram which shows the electrical structure of the input part and display part of the portable liquid detection unit of FIG. The flowchart which shows a liquid level detection process. The timing chart showing the example of transmission / reception of the ultrasonic wave by an ultrasonic transducer in a liquid level detection process. 7 is a flowchart showing data output processing following FIG. Explanatory drawing which shows the memory | storage form of level measurement information. Explanatory drawing which shows the consumption time prediction based on level measurement information. Explanatory drawing which shows the example of a display in a display part. Explanatory drawing which shows the other structural example of the input part and display part of a portable liquid detection unit. The schematic diagram which shows the electrical structure of the input part and display part of the portable liquid detection unit of FIG. The flowchart which shows the other example of a liquid level detection process.

Explanation of symbols

1 Ultrasonic transducer (Ultrasonic output unit; Reflected ultrasonic wave detection unit; Liquid surface position detection means)
1a Ultrasonic wave transmitting / receiving surface 2 Acoustic impedance matching layer 2a Tip surface (container contact surface)
3 Case body 4 Rotating roller 5 Rotary encoder (moving distance measuring means; rotating direction detecting means)
10 Metal tank (container)
10S tank side wall (container wall)
10a Tank wall outer surface (outer wall surface of container)
100 Ultrasonic level meter (portable liquid detection unit)
104 display unit 104a date display unit 104b cylinder display unit 104c level display unit (remaining amount display means)
104d Liquid level detection display unit 105 Input unit 105a Main switch 105b Measurement start / end switch 105c Selection switch (level input means; date input means; cylinder input means)
105d input switch (level input means; date input means; cylinder input means)
105e Confirmation switch (level input means; date input means; cylinder input means)
106 Speaker 107 Microcomputer (liquid level detection control means)
107a CPU (prediction means)
107c RAM (storage means)
107e Built-in clock (date confirmation means)
200 System under test H Total travel distance (container height)
L Liquid LV Liquid level (Liquid surface) position LV0 to LV10 Liquid level (Liquid level position)
Ultrasonic beam for SW measurement

Claims (10)

A portable liquid detection unit used as a system to be measured with a container containing liquid, being movable along the outer surface of the side wall of the container,
An ultrasonic beam for measurement for exciting the system under measurement is output in the thickness direction of the container, and an ultrasonic wave capable of receiving reverberant ultrasonic waves from the system under measurement and reflected ultrasonic waves in the system under measurement is also available. An ultrasonic transducer including an acoustic wave transmitting / receiving surface, and a liquid level position detecting means capable of detecting the liquid level position of the liquid from the outside of the container;
Portable liquid detection comprising: a remaining amount display means for displaying a remaining volume of the liquid contained in the container at a liquid level position level based on the liquid level position detected by the liquid level position detection means. unit. Level input means for artificially inputting the liquid level position level;
Date input means for artificially inputting the date on which the liquid level position level is detected;
Storage means for associating the inputted liquid level position level and date and storing it as level measurement information;
The portable liquid detection unit according to claim 1, further comprising: a predicting unit that predicts a consumption time when the remaining capacity of the liquid becomes a predetermined amount or less from a plurality of level measurement information stored in the storage unit. A portable liquid detection unit used as a system to be measured with a container containing liquid, being movable along the outer surface of the side wall of the container,
An ultrasonic beam for measurement for exciting the system under measurement is output in the thickness direction of the container, and an ultrasonic wave capable of receiving reverberant ultrasonic waves from the system under measurement and reflected ultrasonic waves in the system under measurement is also available. An ultrasonic transducer including an acoustic wave transmitting / receiving surface, and a liquid level position detecting means capable of detecting the liquid level position of the liquid from the outside of the container;
A moving distance measuring means for measuring a moving distance in the vertical direction on the outer surface of the side wall portion starting from a measurement start position determined on the outer surface of the side wall portion of the container;
Based on the liquid level position detected by the liquid level position detecting means and the moving distance measured by the moving distance measuring means, the remaining amount for displaying the remaining capacity of the liquid stored in the container as the liquid level position level. A portable liquid detection unit comprising a display means.   4. The storage device according to claim 3, further comprising a storage unit that stores the liquid level position level detected by the liquid level position detecting unit and the moving distance measuring unit as level measurement information in association with a date when the liquid level position level is detected. Portable liquid detection unit.   The portable liquid detection unit according to claim 4, further comprising a predicting unit that predicts a consumption time when the remaining capacity of the liquid becomes a predetermined amount or less from a plurality of level measurement information stored in the storage unit. The moving distance measuring means detects a relative rotation angle of a rotating roller that rotates in contact with an outer surface of the side wall of the container;
The liquid surface position detecting means detects the liquid surface position when the ultrasonic transducer receives reflected ultrasonic waves or reverberant ultrasonic waves,
The portable liquid detection unit according to any one of claims 3 to 5, wherein the detection of the relative rotation angle of the rotary roller and the detection of the liquid surface position are performed simultaneously.   The moving distance measuring means has a rotation direction detecting means for detecting the rotation direction of the rotating roller, and the detection of the liquid surface position changes from no liquid to presence of liquid depending on the rotation direction detected by the rotation direction detecting means. The portable liquid detection unit according to claim 6, wherein the portable liquid detection unit identifies whether the process is performed in a state of transition or in a state of transition from presence of liquid to absence of liquid.   When the detection of the liquid surface position is determined by reflected ultrasonic information or reverberant ultrasonic information when transitioning from no liquid to liquid presence, the time from the measurement start position to the liquid surface position at the previous measurement The portable liquid detection unit according to any one of claims 3 to 6, wherein the liquid surface position detection means stops the output of the measurement ultrasonic beam from the ultrasonic transducer.   When the detection of the liquid surface position is determined based on reflected ultrasonic information or reverberant ultrasonic information when transitioning from the presence of liquid to the absence of liquid, the liquid surface position detection means performs the superposition after the detection of the liquid surface position. The portable liquid detection unit according to claim 3, wherein the output of the ultrasonic beam for measurement from the sonic transducer is stopped. The moving distance measuring means measures the total stroke moving distance from the measurement start position defined on the outer surface of the side wall of the container to the end point in the vertical direction on the outer surface of the side wall to measure the height of the container And detecting the liquid level position at a midway position of the entire travel distance,
The remaining amount display means displays the remaining volume of the liquid as a liquid surface position level according to the total stroke moving distance and the moving distance to the liquid surface position. Portable liquid detection unit.

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