JP6537846B2 - Silo weighing device - Google Patents

Description

  The present invention relates to a silo measuring device, and more particularly to a device capable of accurately measuring the amount of slaked lime and quicklime stored in a silo storage tank.

  From waste incinerators, there is concern that the exhaust gas contains organic halogen compounds such as dioxins. It is known that this organic halogen compound is generated in the process of cooling in a flue due to HCl present in the exhaust gas. On the other hand, a method is proposed to reduce HCl in exhaust gas and suppress and reduce the formation of organic halogen compounds by injecting and spraying alkaline chemicals such as slaked lime and quicklime into waste incinerators and exhaust gas filters. (Patent Document 1).

  By the way, when slaked lime or quicklime is put into a waste incinerator or an exhaust gas filter and sprayed, it is necessary to accurately manage the amount of slaked lime or quicklime stored in the storage tank of the silo with, for example, a weight of about 100 kg.

  A conventional silo weighing device has an impeller type level meter projecting at different heights on the storage tank side wall of the silo to measure the storage amount, and an ultrasonic type level meter installed at the top of the storage tank There is a method of measuring a storage amount by measuring a time of return of ultrasonic waves from the surface, a method of installing a load cell on the lower side of a storage tank, and a method of measuring a storage amount by detecting a load applied to the load cell.

  However, in the impeller system, although the inside of the storage tank is substantially empty, slaked lime or quick lime adheres to the inner wall surface of the storage tank, and there is a risk of erroneous measurement if there is a storage amount up to the attached height .

  Further, in the ultrasonic method, ultrasonic waves are scattered by the side wall surface due to the vertically long structure of the storage tank, and accurate measurement is difficult if the surface of slaked lime or quick lime is not flat, and there is a possibility of erroneous measurement.

  On the other hand, in the load cell method, the weight of the entire storage tank is measured by the load cell to determine the storage amount, so although it is possible to measure the absolute amount, the weight of slaked lime and quicklime in the storage tank is several tons to several tens Not only does it require a large and expensive load cell, but it also requires a large amount of installation work and increases capital investment.

  On the other hand, a silo measuring device has been proposed in which a strain gauge is attached to a pedestal receiving the storage tank of the silo, the weight of slaked lime and quick lime in the storage tank is determined by the strain gauge, and the storage amount is measured (patented Literature 2).

JP 2001-286726 A JP 2003-240623 A

  However, in the silo measuring device described in Patent Document 2, since the gantry needs to receive a heavy storage tank, it is manufactured as a high-strength structure, and even if it receives the weight of slaked lime or quick lime in the storage tank. The strain was so small that the storage amount could hardly be weighed.

  An object of the present invention is to provide a silo measuring device capable of accurately measuring the storage amount of slaked lime, quick lime, and the like in a storage tank in view of the problems.

  Therefore, in the silo measuring device according to the present invention, the gantry is composed of a circular or square frame and a column for horizontally supporting the frame, and the bottom of the storage tank is formed in an inverted truncated cone or inverted truncated pyramid shape. The frame of the gantry receives the cylindrical body that follows the top of the bottom of the storage tank or above the bottom of the storage tank, while the powder or granular material is stored in the storage tank, and an outlet for storage is formed at the lower end of the storage tank And one or more strain gauges attached to the outer wall surface of the storage tank bottom portion to detect the weight of the stored matter in the storage tank as the magnitude of the strain of the bottom portion outer wall surface; Receiving the signal of the gauge, the inside of the storage tank from the correspondence between the magnitude of distortion of the bottom outer wall of the storage tank, the magnitude of distortion of the outer wall of the bottom of the storage tank, and the amount of the storage in the storage tank Operation to calculate the amount of storage of Characterized by comprising a location, a.

  The main feature of the present invention is to attach a strain gauge to the outer wall surface of the bottom of the inverted frustoconical or inverted truncated pyramidal storage tank, and determine the magnitude of strain corresponding to the weight of the stored material, for example using a function or map The point is to calculate the amount of stock.

  Thereby, the outer wall surface of the bottom of the reservoir receives the weight of the storage and is distorted, which is detected by the strain gauge, but the magnitude of the distortion of the bottom of the storage corresponds linearly to the weight of the storage Compared to the case where the frame of high strength structure is distorted due to the weight of the storage container, the amount of the storage can be accurately measured.

  If there is a large temperature change of the strain gauge under the influence of the high heat of the waste incinerator or exhaust gas filter and there is a concern about the detection error of the strain gauge, it is preferable to detect the atmosphere temperature of the strain gauge to perform temperature compensation.

  In order to obtain high detection accuracy of the strain gauges, it is preferable to use a thin plate full bridge type or thin plate half bridge type strain gauge. Moreover, a thin-type resistance temperature sensor or a thin-type thermocouple can be used for a temperature sensor.

  The cradle is preferably constructed of three or four columns and a circular or square frame, and the reservoir is preferably received at its barrel by the frame of the cradle.

It is a schematic side view showing a silo in a preferred embodiment of a silo measuring device according to the present invention. It is a plane block diagram showing the above-mentioned silo. It is the principal part enlarged view which shows the said silo. It is a figure which shows the example of the distortion sensor used in the said embodiment. It is a functional block diagram showing the operation system in the above-mentioned embodiment. It is a whole block diagram which shows the incineration apparatus to which the said embodiment is applied. It is a figure which shows 2nd Embodiment.

  Hereinafter, the present invention will be described in detail based on specific examples shown in the drawings. 1 to 5 show a preferred embodiment of a silo weighing device according to the present invention. In the figure, the silo 10 is composed of a reservoir 11 and a rack 12, and the reservoir 11 is composed of an inverted truncated conical bottom 11A and a cylindrical body 11B continuous above the bottom 11A. Slaked lime (or quick lime) is stored, and a discharge port 11C is formed at the lower end of the bottom 11A of the storage tank 11.

  On the other hand, the gantry 12 is configured by fixing the columns 12B at four corners of a rectangular frame 12A and horizontally supporting the frame 12A, and a mounting bracket 11D is fixed near the boundary between the bottom 11A and the body 11B of the storage tank 11 The mounting bracket 11D is fixed to the frame 12A so that the boundary between the bottom 11A of the storage tank 11 and the body 11B can be received by the frame 12A of the gantry 12.

  Further, one set or plural sets of the strain sensor 15 and the temperature sensor 16 are attached in close proximity to the outer wall surface of the bottom portion 11A of the storage tank 11, and the strain sensor 15 has a thin plate shape full shown in FIG. The bridge type or thin plate half bridge type strain sensor shown in FIG. 4B is used, the temperature sensor 16 is a thin type thermocouple or resistance temperature detector, and both the strain sensor 15 and the temperature sensor 16 are used. It is sealed by the jig of sealed structure.

  FIG. 5 shows an example of the configuration of an arithmetic system according to this embodiment, which shows an example using four sets of strain sensors and temperature sensors. In the figure, 100A to 100D are strain gauges, 101A to 101D are temperature sensors, 102A to 102D are load cell amplifier AD conversion bases for AD converting the signals of the strain sensors 100A to 100D, 104 generates a reference voltage and the temperature sensor 101A. A reference voltage generating circuit that AD converts a signal of ̃101D and converts it to an output level and outputs it. 103 is a PIO photo conversion circuit that photoconverts signal PIO of conversion base 102A to 102D and outputs it. Touch panel unit for data display / setting with temperature correction of signals from strain sensors 100A to 100D with signals from temperature sensors 101A to 101D with signal PIO of 102D, signal of reference voltage generation circuit 104, and signal of PIO photo conversion circuit as input. 106, RS 422 Arithmetic circuit for outputting the rent loop conversion circuit) 108 and a soft debug EA8 Emireta connection terminals 109, 107 is an output circuit of the weighing data.

  Here, an H8 / 36109G (made by Renesas Electronics Corp.) 1-chip microcomputer can be used as the CPU of the arithmetic circuit 105, the supply voltage can be 5 V, 128 K flash memory can be used in the program area, and 5 K RAM memory can be used in the memory area. . The arithmetic circuit 105 incorporates RS232C (3CH), connects the PIO1 terminal to the outputs of the load cell amplifier AD conversion boards 102A to 102D, and also connects the PIO2 terminal to the IO port (4 inputs, 4 of the photo isolated PIO photo conversion circuit 103). Connected to the output).

  The supply voltage of the load cell amplifier AD conversion base 102A to 102D is + -5V, the distortion sensor supply voltage is 10V, and the reference voltage is amplified and leveled to approximately 2.5V full scale by the feedback power from the amplifier power supply. Convert. The conversion sampling rate and the moving average count of the AD conversion bases 102A to 102D can be changed by the system setting of the operation panel. The zero point and span adjustment of the measured value are calculated by microcomputer software using the AD conversion input value. This value can also be changed by the system setting of the operation panel. Software correction is also performed by weight correction based on the measurement position and temperature correction based on temperature input. This basic coefficient can also be changed by the system setting.

  The connection between the data display / setting touch panel 106 and the computing device 105 uses the RS232C terminal 1, and the data display / setting touch panel unit 106 1) displays the weighing value and setting value, and displays the status (error signal Output, etc.) 2) Display of strain gauge input value and temperature input value, 3) Display of PIO output monitor, 4) Display of system setting screen.

  Transmission of the measured value to the internal data logger uses RS232C terminal 2 of the arithmetic unit 105, and is transmitted by RS422 (curent loop conversion circuit) 108. The input to the PIO isolated conversion circuit is connected as an interlock signal input by a push button switch on the board, an external PLC, or the like. The output of the PIO isolated conversion circuit is connected to an external PLC, a relay on the board, or the like, and is used as an output signal for stopping measurement of measured value, abnormal stop, and the like.

  Next, the method of analyzing the signal from the strain gauge and the temperature sensor will be described. A direct current voltage of about 10 V is applied to the strain gauge 15 from the arithmetic unit, and the weight of the storage is on the bottom wall 11A of the storage tank 11 The distortion corresponding to the magnitude of the distortion occurs, and each strain gauge 15 outputs a DC voltage proportional to the magnitude of the distortion of the bottom portion 11A, and is input to the arithmetic unit.

  On the other hand, the temperature characteristic of the output signal of strain gauge 15 when the load is fixed is previously determined, and in the arithmetic unit, the signal of each strain gauge 15 does not change due to temperature based on the output signal from temperature sensor 16 After being processed, it is added, averaged and displayed as the weight of the silo 10 stock.

  FIG. 6 shows an incinerator to which the silo measuring device of this embodiment is applied. The incinerator comprises a slaked lime hopper 10, an incinerator 20, a table feeder 21, a blower 22, a gas chamber 23, a bag filter 24, a fan 25 and a chimney 26.

  The combustion level of the incinerator 20 is determined according to the incineration temperature and the amount of waste, and the signal a is given to the calculation control system. In the arithmetic control system, the fuel valve control motor is controlled according to the input signal a and the opening and closing of the air damper valve 27 are controlled, and the fuel and slaked lime are input to the incinerator 20 by the blower 22, thereby generating dioxins. Waste is incinerated while being controlled.

  The exhaust gas from the incinerator 20 is sent from the gas chamber 23 to the bag filter 24, but slaked lime is sprayed in the front stage of the bag filter 24, which also suppresses the generation of dioxins and purifies the exhaust gas and discharges it from the chimney 26 Be done.

  Moreover, although the modification of the slaked-lime hopper 10 is shown in FIG. 7, it can replace with the table feeder 21 and the blower 22, and can also be comprised by the mono pump 28. FIG.

  In addition, although the above-mentioned example demonstrated slaked lime silo, it can apply to silos, such as sand and straw.

DESCRIPTION OF SYMBOLS 10 silo 11 storage tank 11A bottom part 11B trunk | drum 11C discharge port 12 mount frame 12A flame | frame 12B support 15 distortion sensor 16 temperature sensor

Claims (2)

The frame comprises a circular or square frame and a column for supporting the frame horizontally, the bottom of the reservoir is formed in an inverted truncated cone or inverted truncated pyramid, and extends above the top or bottom of the bottom of the reservoir. In a silo of a structure in which powdery or granular materials are stored in the storage tank while a discharge port for stored products is formed at the lower end of the storage tank, while the cylindrical body is received by the frame of the gantry.
One or more thin plate full bridges attached to the outer wall surface of the storage tank bottom (11A) and detecting the weight of stored matter in the storage tank (11) as the magnitude of distortion of the outer wall surface of the bottom (11A) Type or thin plate half bridge strain gauge (15),
In response to the signal of the strain gauge (15), the magnitude of distortion of the outer wall surface of the bottom (11A) of the reservoir (11), the magnitude of distortion of the outer wall surface of the reservoir bottom (11A) and the reservoir determined in advance (11) A computing device for computing the amount of stored matter in the storage tank (11) from the correspondence relationship with the amount of stored matter in the storage tank (11);
The silo measuring device characterized by having. It further comprises a thin RTD or a thin thermocouple temperature sensor for detecting the temperature in the vicinity of the strain gauge, and the arithmetic unit receives the output of the temperature sensor and functions to temperature compensate the output of the strain gauge. The silo weighing device according to claim 1, comprising:

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