Pressure control device and pressure control method

Abstract

To provide a pressure control device and a pressure control method for appropriately collecting powder and granule from a powder and granule storage container.SOLUTION: A blower device 23 blows air into an interior of a bulk liner 100 fixed inside a dry container 1 by a connecting string for preventing shrinkage. An information acquisition unit 21 acquires information corresponding to an internal pressure of the bulk liner 100 when a suction device 3 is used to suction a powder and granule from the bulk liner 100 storing the powder and granule. An air blowing control unit 22 controls an amount of air blown from the air blower device 23 based on the information corresponding to the internal pressure of the bulk liner 100 acquired by the information acquisition unit 21.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a pressure control device and a pressure control method.

Background Art

[0002] In a thermal power plant using coal as fuel, a large amount of coal ash is generated during combustion. Coal ash mainly includes two types: fly ash and clinker ash. Fly ash is mainly composed of spherical and extremely small fine particles and accounts for 85-95% of the coal ash generation amount. Fly ash can improve the durability, workability, and fluidity when blended into concrete and can reduce the amount of cement. Therefore, the standard for fly ash for concrete is defined by JIS (Japanese Industrial Standards) standard (JIS A 6201), and fly ash that meets this standard is used as a valuable cement admixture and concrete admixture.

[0003] However, in Japan, the demand for cement has been decreasing year by year. Therefore, it is difficult to increase the effective utilization amount of coal ash in the future. Thus, the strong overseas demand for cement has attracted attention, and the export of fly ash for concrete from Japan to overseas has been under consideration. In the export of fly ash, it is assumed to utilize a transportation method in which fly ash is stored in a bulk liner, which is a bag made of a resin sheet installed in a dry container, and is transported by sea to the destination country. After arriving at the destination country, the fly ash is recovered from the bulk liner at a factory or construction site for manufacturing concrete, transferred to storage facilities such as local storage silos, and then used in a batching plant for manufacturing fresh concrete.

[0004] When recovering fly ash from bulk liners in dry containers, one possible method is to tilt the dry container and let the fly ash fall downwards. However, this method requires placing equipment to receive the fly ash below the bottom of the tilted dry container, and securing a suitable location is not always possible. Furthermore, because fly ash is a fine-grained powder, simply tilting the container makes it difficult to recover all of the fly ash inside.

[0005] Here, as a general equipment for recovering powders and granules, a powder suction and pumping vehicle has been proposed, which uses a vacuum pump to suck up the powders and granules with a suction hose and store them in an on-board tank, and then discharges the contents of the on-board tank to another storage facility such as a silo using an on-board compressor and transfers them. In addition, as a suction device from bulk liners installed in containers, a technology has been proposed in which a suction hose is connected to the bulk liner to suck up the bulk materials stored in the bulk liner. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Utility Model Registration No. 3148187 Gazette [Non-patent literature]

[0007] [Non-Patent Document 1] Australian bulk handling review. January / February 2014. pp. 32-33. [Overview of the project] [Problems that the invention aims to solve]

[0008] However, when a suction hose from a powder and granular material suction / pressure transport vehicle is connected to the bulk liner and suction is performed using a vacuum pump, the bulk liner will contract due to the suction force, even if the bulk liner has an opening for air intake. If there is a large amount of powder and granular material remaining in the bulk liner, the contraction will not be very large, but if the air volume is large, the contraction of the bulk liner will be particularly large. The bulk liner is secured inside the dry container with a string to prevent contraction. By securing it with a string, the contraction of the bulk liner is suppressed even when suction is performed. However, when the bulk liner contracts, the force applied to the attached string increases. Normally, only a small force, about the weight of the bulk liner, is applied to the string attached to the dry container, but if a large force is applied due to the contraction of the bulk liner, there is a risk of the bulk liner being damaged. If the bulk liner is damaged, it becomes difficult to recover the powder and granular material stored in the bulk liner.

[0009] The disclosed technology has been made in view of the above, and aims to provide a pressure control device and a pressure control method for appropriately recovering powders and granules from a powder / granule container. [Means for solving the problem]

[0010] In one embodiment of the pressure control device and pressure control method disclosed in this application, the blower device blows air into the interior of a powder and granular material container fixed inside the container by a connecting string for preventing shrinkage. The tension meter measures the tension of the connecting string. The information acquisition unit, when using a suction device to suck up powder and granular material from the powder and granular material container that stores the powder and granular material, Information on the tension of the connecting string measured by a tension meter The blower control unit obtains the information obtained by the information acquisition unit. The tension of the connecting string Based on the information, the amount of air blown from the blower is controlled. [Effects of the Invention]

[0011] In one respect, the present invention enables the proper recovery of granular material from inside a bulk liner. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a perspective view of a dry container. [Figure 2] Figure 2 is a structural diagram showing a bulk liner disposed within the dry container. [Figure 3] Figure 3 is a block diagram of the pressure control device according to Example 1. [Figure 4] Figure 4 is a diagram showing an overview of the fly ash discharge test from the bulk liner. [Figure 5] Figure 5 is a diagram showing the test results of the discharge test. [Figure 6] Figure 6 is a flowchart of the fly ash recovery process using the pressure control device according to Example 1. [Figure 7] Figure 7 is a diagram showing the relationship between the control signal to the inverter and the blower air volume. [Figure 8] Figure 8 is a flowchart of the fly ash recovery process using the pressure control device according to Example 2. [Figure 9] Figure 9 is a block diagram of the pressure control device according to Example 3.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the pressure control device and the pressure control method disclosed in the present application will be described in detail based on the drawings. Note that the pressure control device and the pressure control method disclosed in the present application are not limited by the following embodiments.

Examples

[0014] Figure 1 is a perspective view of a dry container. Figure 2 is a structural diagram showing a bulk liner disposed within the dry container. Figure 2 shows the bulk liner 100 installed within the dry container in Figure 1, and is shown with some of the walls and supports removed for clarity.

[0015] As shown in Figure 1, the dry container 1 has a rectangular parallelepiped shape with a door. A dry container 1 conforming to the ISO (International Organization for Standardization) standard used in maritime transport typically has only one door at the rear that can be opened and closed. Opening the door of the dry container 1 allows access to the bulk liner 100 stored inside. The dry container 1 is positioned with one of its four longitudinally extending faces facing the ground. In the following description, the face facing the ground when the dry container 1 is positioned will be referred to as the bottom, and the face opposite the bottom will be referred to as the top. The door of the dry container 1 is located on one of the longitudinally extending faces.

[0016] As shown in Figure 2, the bulk liner 100 is positioned inside the frame 11 of the dry container 1. The bulk liner 100 has a rectangular parallelepiped shape that adheres tightly to the inner wall of the dry container 1 while maximizing the internal space.

[0017] The bulkliner 100 has loading tubes 101, ventilation tubes 102, and unloading tubes 103 on one end face in the longitudinal direction. The bulkliner 100 is positioned so that the side on which the loading tubes 101, ventilation tubes 102, and unloading tubes 103 are located faces the door side of the dry container 1. That is, when the door of the dry container 1 is open, the loading tubes 101, ventilation tubes 102, and unloading tubes 103 are accessible from the outside.

[0018] Furthermore, the bulk liner 100 is positioned such that the loading tube 101 and ventilation tube 102 are located on the upper side of the dry container 1, and the unloading tube 103 is located on the lower side of the dry container 1.

[0019] The loading tube 101 is used to bring fly ash into the bulk liner 100. The fly ash is pumped into the bulk liner 100 and accumulated through the loading tube 101.

[0020] The unloading tube 103 is used to recover fly ash from inside the bulk liner 100. The fly ash is sucked out and recovered from inside the bulk liner 100 via the unloading tube 103.

[0021] The ventilation tube 102 connects the inside and outside of the bulkliner 100, allowing for the intake and exhaust of air to and from the bulkliner 100. The ventilation tube 102 is opened when fly ash is taken into the bulkliner 100 using the loading tube 101, allowing air inside the bulkliner 100 to be expelled to the outside. The ventilation tube 102 is also opened when the dry container 1 is tilted and dropped downwards for discharge, supplying air into the dry container 1. The ventilation tube 102 also serves as a path for supplying air into the bulkliner 100 when fly ash is sucked out of the bulkliner 100 using the unloading tube 103.

[0022] However, when using the unloading tube 103 to suck fly ash out of the bulk liner 100, if the ventilation tube 102 is simply left open to the outside, the volume sucked out from the unloading tube 103 will be greater than the volume of air taken in from the ventilation tube 102, causing the bulk liner 100 to contract. Therefore, in order to maintain the shape of the bulk liner 100, in this embodiment, air is forcibly supplied from the ventilation tube 102 under predetermined conditions, as will be described later. Conversely, if the amount of air supplied is too large, the bulk liner 100 may expand, potentially leading to rupture or deformation of the dry container 1.

[0023] Furthermore, the bulk liner 100 has mounting fixtures 104 on the inner surface of the upper surface of the dry container 1, which is the surface facing the ceiling. In Figure 2, the bulk liner 100 has two mounting fixtures 104 near each vertex of the surface facing the ceiling of the dry container 1. The mounting fixtures 104 are fixed and supported to the frame 11 of the dry container 1 by connecting strings 150 to prevent the bulk liner 100 from shrinking, thereby maintaining the shape of the bulk liner 100.

[0024] The mounting bracket 104 is pulled towards the ceiling by the connecting cord 150 to prevent the bulkliner 100 from collapsing even when the bulkliner 100 contains only a small amount of fly ash and has a large empty space inside. In other words, when the internal pressure of the bulkliner 100 decreases, the mounting bracket 104 moves away from the inner wall of the dry container 1, so the force applied to the mounting bracket 104 by the connecting cord 140 increases. If the force pulling the mounting bracket 104 by the connecting cord 150 increases, there is a risk that the mounting bracket 104 portion of the bulkliner 100 may be damaged.

[0025] Figure 3 is a block diagram of the pressure control device according to Embodiment 1. Figure 3 shows the state in which fly ash is recovered from inside the bulk liner 100. As shown in Figure 3, when recovering fly ash, the suction device 3 is connected to the unloading tube 103 of the bulk liner 100. In addition, the blower 23 of the pressure control device 2 is connected to the ventilation tube 102 of the bulk liner 100.

[0026] The suction device 3 uses a vacuum pump or the like to suck up the fly ash stored inside the bulkliner 100, removing the fly ash from inside the bulkliner 100. The suction of fly ash by the suction device 3 reduces the pressure inside the bulkliner 100. The amount of air sucked in by the suction device 3 varies depending on the ratio of fly ash to air being sucked in, and changes during suction.

[0027] The pressure control device 2 adjusts the internal pressure of the bulkliner 100 by supplying air through the ventilation tube 102 to the bulkliner 100 when recovering fly ash from inside the bulkliner 100. By supplying air when the pressure is low, the pressure control device 2 prevents damage to the bulkliner 100 caused by the mounting fixture 104 being pulled by the connecting string 150 due to a decrease in internal pressure. Furthermore, by stopping the supply of air when the pressure becomes high, the pressure control device 2 prevents over-expansion of the bulkliner 100. The details of the pressure control device 2 are described below.

[0028] As shown in Figure 3, the pressure control device 2 includes an information acquisition unit 21, a blower control unit 22, a blower 23, and a tension meter 200.

[0029] The blower 23 is a blower, compressor, or electric blower, for example. 3 You can use a Roots blower with a / min output, etc.

[0030] A tension meter 200 is installed on each connecting cord 150 that connects the dry container 1 and the bulk liner 100. The tension meter 200 measures the tension exerted on the connecting cord 150 by the dry container 1 and the attachment 104. In other words, the tension meter 200 measures the magnitude (absolute value) of the negative pressure inside the bulk liner 100. Here, the tension applied to one connecting cord 150 is considered the magnitude of the negative pressure inside the bulk liner 100. The tension meter 200 is, for example, a tensile load cell with a measurement range of 0 to 20 kg. The tension meter 200 outputs the measured value in the range of 0 to 20 kg as the tension of the connecting cord 150.

[0031] The information acquisition unit 21 is implemented, for example, by a communication device and a load cell converter. The information acquisition unit 21 is connected to each tension meter 200 by the communication device. The information acquisition unit 21 collects information on the tension of the connecting string 150 measured by each tension meter 200. The information acquisition unit 21 then converts the collected tension information of the connecting string 150 into a current signal in the range of, for example, 4 to 20 mA, using a load cell converter and outputs it to the airflow control unit 22.

[0032] The airflow control unit 22 controls the amount of air that the blower 23 sends into the bulkliner 100 via the ventilation tube 102. The airflow control unit 22 is implemented, for example, by a limiter alarm. The airflow control unit 22 has pre-defined thresholds for adjusting the internal pressure of the bulkliner 100. In this embodiment, the airflow control unit 22 has a threshold for the tension of the connecting string 150 to determine whether there is a risk of damage to the bulkliner 100 due to the attachment 104 being pulled by the connecting string 150. For example, the airflow control unit 22 has an airflow start threshold of 2.5 kg = 6 mA and an airflow stop threshold of 0.5 kg = 4.4 mA.

[0033] The airflow control unit 22 turns off the airflow device 23 when suction by the suction device 3 begins, stopping the airflow to the bulkliner 100. When fly ash is being sucked from the bulkliner 100, the airflow control unit 22 receives a current signal input from the information acquisition unit 21 that represents the tension of each connecting cord 150. The airflow control unit 22 then uses a limiter alarm to determine whether the tension on any of the connecting cords 150 is above the airflow start threshold based on whether the current signal is above the airflow start threshold. If the tension is not above the airflow start threshold, the airflow control unit 22 maintains the state in which the airflow from the airflow device 23 is stopped.

[0034] In response to this, if the tension exceeds the blowing start threshold, the blowing control unit 22 turns on the blower 23 to start blowing air to the bulkliner 100. That is, the blowing control unit 22 turns on the blower 23 to start blowing air to the bulkliner 100 when the magnitude of the negative pressure inside the bulkliner 100 exceeds the blowing start threshold. Subsequently, the blowing control unit 22 determines whether the tension on all connecting cords 150 has fallen below the blowing stop threshold by using a limiter alarm to determine whether the current signal is below the blowing stop threshold. If all tensions have fallen below the blowing stop threshold, the blowing control unit 22 turns off the blower 23 to stop blowing air to the bulkliner 100.

[0035] While the fly ash is being sucked up by the suction device 3, the air blower control unit 22 repeatedly controls the on / off state of the air blower 23 based on the tension applied to the connecting string 150 described above. Then, when the air blower control unit 22 confirms that the fly ash has been sucked up by the suction device 3, such as when the operator requests it to stop, it stops controlling the on / off state of the air blower 23.

[0036] In this embodiment, the suction device 3 was controlled by monitoring the tension of each connecting string 150. However, the suction device 3 may be controlled by monitoring the tension of only the connecting string 150 that is thought to have the most tension, or a few connecting strings 150 including that string.

[0037] Next, we will describe the test results of the fly ash discharge test from the bulk liner 100. Figure 4 is a diagram showing an overview of the fly ash discharge test from the bulk liner. In this test, the dry container 1 was tilted so that the fly ash would collect on the side of the unloading tube 103. The amount of fly ash in the bulk liner 100 during the discharge test was 19 tons.

[0038] In the discharge test, a granular material suction and pumping vehicle 30 was used. The granular material suction and pumping vehicle 30 pumped fly ash sucked from the bulk liner 100 to the mobile silo. The performance of the granular material suction and pumping vehicle 30 was as follows: dump angle of 45 degrees, suction airflow of 80 m³ 3 The value is / min (at -13kPa), the static pressure is -93kPa, and the compressed air volume is 8.0m³. 3 The rate is / min. Furthermore, the powder and granular material suction and pumping vehicle 30 has a dry, self-cooling rotary blower as its suction device 3.

[0039] Furthermore, the blower 23 has an airflow of 74 m³. 3 An electric blower with a motor output of 2.2 kW was used, with a flow rate of / min. In this case, the blower 23 can supply air at approximately the same rate as the suction airflow of the powder and granular material suction and pumping vehicle 30.

[0040] Figure 5 shows the results of the discharge test. In Figure 5, the vertical axis on the left side of the page shows the amount of dry ash remaining, and the vertical axis on the right side shows the tilt angle of dry container 1. The horizontal axis of Figure 5 represents the passage of time. Graph 301 shows the change in the amount of fly ash remaining. Graph 302 shows the change in the tilt angle of dry container 1.

[0041] In the discharge test, as shown in Figure 5, the discharge time was approximately 2 hours and 30 minutes. However, times 311 and 312 represent the time spent on external pumping operations due to the onboard tank of the granular material suction and pumping vehicle 30 becoming full. Excluding times 311 and 312, the time during which the granular material suction and pumping vehicle 30 performed suction was approximately 2 hours. By switching the blower 23 on and off according to the tension of the connecting string 150 during suction by the granular material suction and pumping vehicle 30, all of the fly ash in the bulk liner 100 was recovered without reducing the amount of suction by the granular material suction and pumping vehicle 30, as shown in Figure 5.

[0042] Figure 6 is a flowchart of the fly ash recovery process using the pressure control device according to Example 1. Next, referring to Figure 6, the flow of the fly ash recovery process from the bulk liner 100 mounted on the dry container 1 using the pressure control device 2 according to Example 1 will be explained.

[0043] The suction device 3 sucks fly ash from the bulk liner 100 via the unloading tube 103 (step S1).

[0044] The information acquisition unit 21 acquires the measurement result of the tension of the connecting string 150 by the tension meter 200 (step S2).

[0045] The airflow control unit 22 receives the measurement result of the tension of the connecting cord 150 from the information acquisition unit 21. The airflow control unit 22 then determines whether the tension of the connecting cord 150 is equal to or greater than the airflow start threshold (step S3).

[0046] If the tension of the connecting cord 150 is greater than or equal to the airflow start threshold (step S3: affirmative), the airflow control unit 22 turns on the air blower 23 to blow air to the bulkliner 100 via the ventilation tube 102 (step S4).

[0047] In contrast, if the tension of the connecting cord 150 is less than the airflow start threshold (step S3: negative), the airflow control unit 22 proceeds to step S5.

[0048] Next, it is determined whether the tension of the connecting cord 150 is below the airflow stop threshold (step S5). If the tension of the connecting cord 150 is greater than the airflow stop threshold (step S5: negative), the airflow control unit 22 proceeds to step S7.

[0049] If the tension of the connecting cord 150 is below the airflow stop threshold (step S5: affirmative), the airflow control unit 22 turns off the airflow device 23 to stop the airflow to the bulkliner 100 via the ventilation tube 102 (step S6).

[0050] Subsequently, the blower control unit 22 determines whether or not fly ash collection has been completed based on whether or not there is a stop command from the operator (step S7). If fly ash collection has not been completed (step S7: negative), the collection process returns to step S1.

[0051] In response to this, if the fly ash collection is completed (step S7: affirmative), the pressure control device 2 terminates the pressure control inside the bulkliner 100.

[0052] As described above, the pressure control device according to this embodiment determines that the internal pressure inside the bulk liner is low when the tension of the connecting string that secures the bulk liner to the dry container is above the blowing start threshold during fly ash suction. The pressure control device then blows air into the bulk liner when the internal pressure inside the bulk liner becomes low. Furthermore, the pressure control device determines that the internal pressure inside the bulk liner is not low when the tension of the connecting string that secures the bulk liner to the dry container is below the blowing stop threshold during fly ash suction, and stops blowing air into the bulk liner. In this way, the pressure control device suppresses the pressure drop inside the bulk liner due to fly ash suction, thereby suppressing damage to the bulk liner, and also suppresses over-expansion of the bulk liner due to excessive blowing. Therefore, it becomes possible to properly recover the powder and granular material inside the bulk liner. [Examples]

[0053] Next, Example 2 will be described. The pressure control device 2 in this example differs from Example 1 in that it gradually changes the amount of air blown by the blower 23 in proportion to the output of the tension meter 200. The pressure control device 2 in this example is also represented by the block diagram in Figure 3. In the following description, the operation of each part, which is the same as in Example 1, will be omitted.

[0054] The airflow control unit 22 stores in advance the amount of increase or decrease in the airflow volume of the air blower 23 for each step. For example, the airflow control unit 22 sets the amount of increase or decrease for each step to 20% of the maximum airflow volume of the air blower 23. The airflow control unit 22 then acquires information on the tension of the connecting string 150, measured by the tension meter 200, from the information acquisition unit 21.

[0055] The airflow control unit 22 then calculates the amount of air blown by the air blower 23 according to the tension of the connecting cord 150. Specifically, the airflow control unit 22 calculates the amount of air blown by the air blower 23 so that it increases in proportion to the tension of the connecting cord 150. The airflow control unit 22 then causes the air blower 23 to blow air to the bulkliner 100 via the ventilation tube 102 with the calculated amount of air blown. For example, the airflow control unit 22 controls the amount of air blown by the air blower 23 as follows.

[0056] The airflow control unit 22 includes, for example, an inverter. The inverter converts the commercial power supply to DC, then converts it to AC of an arbitrary frequency in the inverter circuit, and changes the rotational speed of the motor of the blower 23. The relationship between the input control signal sent to the inverter and the airflow rate of the blower connected to the inverter is shown in Figure 7. Figure 7 is a diagram showing the relationship between the control signal to the inverter and the airflow rate of the blower. A three-phase 200V inverter with a maximum output of 15kW was used. For example, the airflow control unit 22 sets a function in the inverter that associates the operating frequency required for a blower airflow rate of 0 to 50 m³ / min with a 4 to 20 mA signal input from the information acquisition unit 21 as shown in Figure 7. The airflow control unit 22 then inputs the current signal from the information acquisition unit 21 to the inverter and controls the motor of the blower at the corresponding frequency, operating the blower 23 so that the required airflow rate is secured.

[0057] In this embodiment, the airflow control unit 22 calculates the airflow rate using a function that represents the relationship between the tension of the connecting cord 150 and the airflow rate, but the method of calculating the airflow rate is not limited to this. For example, the airflow control unit 22 may divide the period from airflow stop to maximum airflow into several sections and use a table in which the tension of the connecting cord 150 is registered for each section to calculate the airflow rate according to the tension of the connecting cord 150. Alternatively, for example, the airflow control unit 22 may calculate the airflow rate using the increase or decrease amount for each step.

[0058] For example, the airflow control unit 22 may change the airflow rate of the blower 23 in steps as follows: When the tension of the connecting string 150 is above a threshold, the airflow control unit 22 increases the airflow rate of the blower 23 by one step. That is, if the tension of the connecting string 150 is above the threshold repeatedly, the airflow control unit 22 gradually increases the airflow rate of the blower 23, up to the maximum airflow rate limit. Also, when the tension of the connecting string 150 is below the threshold, the airflow control unit 22 decreases the airflow rate of the blower 23 by one step. That is, if the tension of the connecting string 150 is below the threshold repeatedly, the airflow control unit 22 gradually decreases the airflow rate of the blower 23, up to the point where the airflow stops.

[0059] Figure 8 is a flowchart of the fly ash recovery process using the pressure control device according to Example 2. Next, referring to Figure 8, the flow of the fly ash recovery process from the bulk liner 100 mounted on the dry container 1 using the pressure control device 2 according to Example 2 will be explained.

[0060] The suction device 3 sucks fly ash from the bulk liner 100 via the unloading tube 103 (step S11).

[0061] The information acquisition unit 21 acquires the measurement result of the tension of the connecting string 150 by the tension meter 200 (step S12).

[0062] The airflow control unit 22 receives the measurement result of the tension of the connecting string 150 as input from the information acquisition unit 21. The airflow control unit 22 then calculates the amount of airflow corresponding to the tension of the connecting string 150 (step S13).

[0063] Next, the airflow control unit 22 controls the air blower 23 to the calculated airflow rate and blows air to the bulkliner 100 via the ventilation tube 102 (step S14).

[0064] Subsequently, the blower control unit 22 determines whether or not fly ash collection has been completed based on whether or not there is a stop command from the operator (step S15). If fly ash collection has not been completed (step S15: negative), the collection process returns to step S11.

[0065] In response to this, if the fly ash collection is completed (step S15: affirmative), the pressure control device 2 terminates the pressure control inside the bulkliner 100.

[0066] As described above, the pressure control device according to this embodiment gradually changes the airflow rate of the blower in accordance with the output of the tension meter. This makes it possible to more appropriately manage the pressure inside the bulk liner, suppress damage and over-expansion of the bulk liner, and enable proper recovery of the powder and granular material inside the bulk liner. [Examples]

[0067] Figure 9 is a block diagram of the pressure control device according to Embodiment 3. The pressure control device 2 according to this embodiment differs from Embodiment 1 in that it uses a pressure sensor 201 installed in the bulkliner 100 to detect changes in the pressure inside the bulkliner 100 and control the airflow rate. In the following description, the operation of each part, which is the same as in Embodiment 1, will be omitted.

[0068] The pressure control device 2 according to this embodiment has a pressure sensor 201. The pressure sensor 201 is placed inside the bulk liner 100. The pressure sensor 201 measures the pressure inside the bulk liner 100. Here, since the pressure change inside the bulk liner 100 due to fly ash suction is a negative pressure of several hPa, it is preferable to use a differential pressure gauge for the pressure sensor 201.

[0069] The information acquisition unit 21 is connected to the pressure sensor 201. The information acquisition unit 21 acquires information on the internal pressure of the bulkliner 100 measured by the pressure sensor 201 and outputs it to the airflow control unit 22.

[0070] The air blower control unit 22 stores in advance an air blowing start pressure threshold and an air blowing stop pressure threshold for determining the risk of damage to the bulkliner 100. For example, the load on the connecting cord 150 when a differential pressure of 1 hPa is applied to the inside and outside of the bulkliner 100 is estimated to be 20 to 40 kg / cord on average. Therefore, the air blower control unit 22 stores, for example, the air blowing start pressure threshold as 0.1 hPa, which is a negative pressure from the atmospheric pressure outside the container, and the air blowing stop pressure (negative pressure) as 0.025 hPa.

[0071] The airflow control unit 22 obtains information on the internal pressure of the bulkliner 100, measured by the pressure sensor 201, from the information acquisition unit 21. The airflow control unit 22 then determines whether the absolute value of the negative pressure inside the bulkliner 100, measured by the pressure sensor 201, is equal to or greater than the airflow start pressure threshold. The airflow control unit 22 also determines whether the absolute value of the negative pressure in the bulkliner 100, measured by the pressure sensor 201, is equal to or less than the airflow stop pressure threshold.

[0072] If the absolute value of the negative pressure inside the bulkliner 100 is equal to or greater than the blowing start pressure threshold, the blowing control unit 22 turns on the blower 23 to start blowing air to the bulkliner 100. Also, if the absolute value of the negative pressure inside the bulkliner 100 is equal to or less than the blowing stop pressure threshold, the blowing control unit 22 turns off the blower 23 to stop blowing air to the bulkliner 100.

[0073] In this embodiment, the amount of air blown was adjusted by on / off control of the blower 23, similar to Embodiment 1. However, even when using a pressure sensor 201 as in this embodiment, the amount of air blown may be gradually changed in proportion to the measurement value of the pressure sensor 201, as in Embodiment 2.

[0074] As described above, the pressure control device according to this embodiment measures the pressure inside the bulk liner and controls the blower based on the measurement results. In this way, even when using the pressure inside the bulk liner, the pressure control device can suppress the pressure drop inside the bulk liner due to fly ash suction, thereby suppressing damage to the bulk liner, and can also suppress over-expansion of the bulk liner due to excessive blowing. Therefore, it becomes possible to properly recover the powder and granular material inside the bulk liner. [Explanation of Symbols]

[0075] 1 dry container 2. Pressure control device 3 Suction device 11 frames 21 Information Acquisition Department 22 Air blower control unit 23 Blower 100 Bulkliner 101 Loading tube 102 Ventilation tube 103 Unloading tube 104 Mounting hardware 150 connecting cords 200 tension meter 201 Pressure Sensor

Claims

1. A blower that blows air into the container holding powders and granules, which is fixed inside the container by connecting strings to prevent shrinkage, A tension meter for measuring the tension of the connecting string, When suctioning granular material from a container containing granular material using a suction device, an information acquisition unit acquires information on the tension of the connecting string measured by the tension meter, Based on the tension information of the connecting string acquired by the information acquisition unit, the airflow control unit controls the amount of air blown from the blower. A pressure control device characterized by being equipped with the following:

2. The pressure control device according to claim 1, characterized in that the air supply control unit causes the air supply device to supply air when the tension of the connecting string is equal to or greater than the air supply start threshold.

3. The pressure control device according to claim 2, characterized in that the air blowing control unit stops the air blowing of the air blowing device when the tension of the connecting string is below an air blowing stop threshold.

4. The pressure control device according to claim 1, characterized in that the airflow control unit controls the amount of airflow in proportion to the tension of the connecting string.

5. The container for containing the powder and granules further includes a pressure sensor for measuring the pressure inside the container, The information acquisition unit acquires information on the pressure inside the powder container measured by the pressure sensor, The air blowing control unit controls the amount of air blown from the blowing device based on information about the tension of the connecting string and information about the pressure inside the powder container. The pressure control device according to claim 1.

6. The powder and granular material are sucked out of the container, which is fixed inside the container by connecting strings to prevent shrinkage, using a suction device. The tension of the connecting string is measured using a tension meter. Information corresponding to the pressure inside the container containing the powder and granules is obtained, Based on the tension information of the connecting string measured by the tension meter, the amount of air blown by the blower is controlled to blow air into the container holding the powder or granular material. A pressure control method characterized by the following:

Images