Pneumatic Unloader

Abstract

To reduce maintenance frequency by eliminating clearance adjustment work.SOLUTION: A pneumatic unloader comprises: a receiver tank 2 storing a sucked load; a first slide gate G1 and a second slide gate G2 provided in series in the order from below at an outlet portion 31 of the receiver tank; a first level sensor S1 for detecting the presence or absence of a load at a position between the first slide gate and the second slide gate; a second level sensor S2 for detecting the presence or absence of a load at a position above the second slide gate; and a control device E controlling the first slide gate and the second slide gate on the basis of the detection result of the first level sensor and the second level sensor.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This disclosure relates to a pneumatic unloader.

Background Art

[0002] Generally, in a port, a pneumatic unloader is installed to lift and discharge goods such as grains carried by ships.

[0003] This pneumatic unloader is equipped with a rotary feeder to discharge (cut off) the lifted goods at a substantially constant flow rate. The rotary feeder is designed to efficiently discharge the goods from the vacuum side to the atmosphere while minimizing air leakage by adjusting the gap between the blades at the tip of the rotor and the side cover and casing.

[0004] The position of the blade and the gap can be adjusted by attaching bolts inserted into the long holes of the blade to the rotor. When the blade wears due to long-term use, the gap becomes larger, the air leakage increases, and the efficiency decreases. Therefore, in such a case, an adjustment is made to shift the mounting position of the blade to reduce the gap.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, rotary feeders present a problem due to the adjustment and maintenance required as blades wear down. When the blades wear down, their position needs to be adjusted, and eventually, the blades need to be replaced. These maintenance tasks must be performed in the cramped space on the unloader machine. In addition, rotary feeders are sometimes transported to the factory for maintenance, in which case the rotary feeder must be removed in the cramped space on the unloader machine.

[0007] Furthermore, even if the gaps are adjusted, air leakage is unavoidable due to the inherent structure, which could negatively impact the efficiency of the unloader.

[0008] Therefore, this disclosure was conceived in view of these circumstances, and one of its purposes is to provide a pneumatic unloader that can reduce the frequency of maintenance by eliminating the need for gap adjustment work.

[0009] Another object of this disclosure is to provide a pneumatic unloader that can reduce the amount of leaked air by reducing the gap and improve efficiency. [Means for solving the problem]

[0010] According to one aspect of this disclosure, A receiver tank for storing the sucked-in load, The receiver tank outlet is provided with a first slide gate and a second slide gate arranged in series from below, A first level sensor for detecting the presence or absence of a load at a position between the first slide gate and the second slide gate, A second level sensor for detecting the presence or absence of a load at a position above the second slide gate, A control device that controls the first slide gate and the second slide gate based on the detection results of the first level sensor and the second level sensor, A pneumatic unloader is provided, characterized by having the following features.

[0011] Preferably, the control device controls the first slide gate and the second slide gate so as to fill the space in the receiver tank between the first slide gate and the first level sensor with a load.

[0012] Preferably, the pneumatic unloader includes a third level sensor for detecting the presence or absence of a load at a position above the second level sensor. The control device also controls the first slide gate and the second slide gate based on the detection result of the third level sensor.

[0013] Preferably, the pneumatic unloader includes a third slide gate located below the first slide gate.

[0014] Preferably, if the control device sends an open command to the fully closed first slide gate or the second slide gate, but the first slide gate or the second slide gate does not open, the control device fully closes the third slide gate. [Effects of the Invention]

[0015] According to this disclosure, the need for gap adjustment work can be eliminated, reducing the frequency of maintenance. In addition, efficiency can be improved by reducing the amount of leaked air by narrowing the gap. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram of a pneumatic unloader according to an embodiment of the present disclosure. [Figure 2] This is a side cross-sectional view showing the feeding device of this embodiment. [Figure 3] This is a plan view showing the fixed gate member. [Figure 4] This is a plan view showing the movable gate member. [Figure 5] This is a plan view showing the first slide gate when fully open. [Figure 6]It is a side cross-sectional view showing the first slide gate when fully open. [Figure 7] It is a side cross-sectional view showing the first slide gate when half open. [Figure 8] It is a side cross-sectional view showing the first slide gate when fully closed. [Figure 9] It is a flowchart showing the content of normal control in the feeding device. [Figure 10] It is a flowchart showing the content of diagnostic recovery control.

Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that it should be noted that the present disclosure is not limited to the following embodiments.

[0018] As shown in FIG. 1, in the harbor, a ship S on which a load B of bulk goods such as grains is loaded in a cargo hold K is docked. And on the quay wall Q of the harbor, a pneumatic unloader (hereinafter simply referred to as an unloader) 100 for sucking up and discharging the load B stored in the cargo hold K is installed. For the sake of convenience, the respective directions of front, rear, left, right, up, and down are defined as shown in the figure.

[0019] A pair of rails R extending along the quay wall Q are installed on the quay wall Q, and the unloader 100 is provided with a traveling gantry 1 that can travel on the rails R. The unloader 100 also includes a receiver tank 2 that can rotate on the traveling gantry 1. The receiver tank 2 can rotate around a vertical rotation axis C1 with respect to the traveling gantry 1 as shown by an arrow a.

[0020] One end of an air suction pipe 3 is connected to the top of the receiver tank 2, and the other end of the air suction pipe 3 is connected to a vacuum pump 4 composed of, for example, a roots blower. The vacuum pump 4 is installed in a machine room 5 connected to the receiver tank 2.

[0021] The base end of a horizontally extending pipe 6 is connected via a ball joint 19 to the inlet 35 (see Figure 2), which is the inlet for the load B of the receiver tank 2. The horizontal pipe 6 is extendable and retractable in its longitudinal direction as indicated by arrow b, allowing adjustment of the position of the nozzle 7, which is the suction port for the load B, in the horizontal direction or along the longitudinal direction of the horizontal pipe.

[0022] The receiver tank 2 has a boom 8, indicated by a dashed line, attached to its base so as to be able to be raised and lowered as shown by arrow c. The horizontal pipe 6 is attached along the boom 8 and is able to be raised and lowered together with the boom 8. In the illustrated example, the horizontal pipe 6 and boom 8 extend toward the sea side or toward the ship S side (forward side).

[0023] The base end of a curved pipe 9, which is bent downwards at a 90° angle, is integrally attached to the tip of the horizontal pipe 6. The base or upper end of a vertical pipe 10, which extends vertically, is rotatably connected to the tip of the curved pipe 9 via a swing joint 11, as indicated by arrow d.

[0024] During cargo handling operations, the vertical pipe 10 is inserted into the cargo hold K through the hatch H of the ship S. The vertical pipe 10 is extendable and retractable in its longitudinal direction as indicated by arrow e, allowing the height of the nozzle 7 to be adjusted according to the height of the cargo B or the ship S.

[0025] A nozzle 7 is attached to the tip or lower end of the vertical pipe 10. The nozzle 7 approaches or comes into contact with the cargo B in the cargo hold K to suck up the cargo B in the cargo hold K.

[0026] To allow for fine adjustment of the position and orientation of the nozzle 7, the upper and lower ends of the vertical tube 10 are formed by flexible tubes 12.

[0027] A filter, or bag filter 13, is provided at the upper end of the receiver tank 2 to prevent load B from being sucked into the vacuum pump 4.

[0028] Furthermore, a chute 14 is provided below the receiver tank 2, which is used to drop and supply the load B discharged from the outlet of the receiver tank 2 to one end of the in-machine conveyor 15.

[0029] A ground chute 16 is provided projecting downward from the other end of the in-machine conveyor 15. The load B that has been transported to the other end of the in-machine conveyor 15 is dropped and supplied to the ground conveyor 17 through the ground chute 16. In this embodiment, multiple (two) ground chutes 16 are provided to correspond to multiple (two) ground conveyors 17. A slide gate 18 is provided at the upper end of each ground chute 16, allowing selection of the ground chute 16 to be used for supplying load B to the ground conveyor 17.

[0030] Furthermore, the chute 14 and the internal conveyor 15 are installed on the side of the travel frame 1 and do not rotate together with the receiver tank 2. The ground chute 16 may be reduced to one, and the slide gate 18 may be omitted.

[0031] Conventionally, a rotary feeder, which serves as a vacuum dispensing or feeding device, is installed in the middle of the chute 14. This rotary feeder controls the discharge flow rate of load B to the in-machine conveyor 15 (the amount of load B discharged per unit time) to be approximately constant, and also separates the vacuum side from the atmospheric side. That is, the area above the rotary feeder is the vacuum side, and the area below it is the atmospheric side.

[0032] However, using a rotary feeder presents the aforementioned challenges, namely the troublesome maintenance required and reduced efficiency due to gaps.

[0033] Therefore, this embodiment solves the above problem by installing a different feeding device in place of the rotary feeder.

[0034] Figure 2 shows the dispensing device of this embodiment. The dispensing device 30 includes the above-mentioned receiver tank 2 for storing the sucked load B, and a first slide gate G1 and a second slide gate G2 which are provided in series from below at the outlet portion 31 of the receiver tank 2.

[0035] The dispensing device 30 also includes a first level sensor S1 for detecting the presence or absence of load B at a position between the first slide gate G1 and the second slide gate G2, a second level sensor S2 for detecting the presence or absence of load B at a position above the second slide gate G2, and a control device E that controls the first slide gate G1 and the second slide gate G2 based on the detection results of the first level sensor S1 and the second level sensor S2.

[0036] Furthermore, the dispensing device 30 of this embodiment is equipped with a third level sensor S3 for detecting the presence or absence of load B at a position above the second level sensor S2. The control device E controls the first slide gate G1 and the second slide gate G2 based on the detection result of the third level sensor S3.

[0037] Furthermore, the feeding device 30 of this embodiment includes a third slide gate G3 located below the first slide gate G1.

[0038] The following describes each part in detail. The receiver tank 2 is a vertically elongated cylindrical container having a central axis C2 that is coaxial with the pivot axis C1. Hereinafter, the axial, radial, and circumferential directions with respect to the central axis C2 will simply be referred to as the axial, radial, and circumferential directions.

[0039] The receiver tank 2 has a main cylindrical section 32 with a constant radius, a tapered cylindrical section 33 connected to the lower end of the main cylindrical section 32 and gradually decreasing in diameter as it extends downward, and an outlet cylindrical section 34 connected to the lower end of the tapered cylindrical section 33 and having a constant radius smaller than that of the main cylindrical section 32. An inlet 35 for supplying or depositing load B into the receiver tank 2 is connected at a predetermined height position of the main cylindrical section 32, extending diagonally downward. This inlet 35 is connected to the ball joint 19 shown in Figure 1, and receives load B from the ball joint 19. The outlet cylindrical section 34 defines the outlet 36 for load B in the receiver tank 2. The outlet cylindrical section 34 is connected in series with the aforementioned chute 14.

[0040] The first slide gate G1 and the second slide gate G2 are located at a height below the input opening 35 in the main cylinder section 32. The first slide gate G1 is located at a height near the lower end of the main cylinder section 32, and the second slide gate G2 is located at a height a predetermined distance higher than the first slide gate G1. The third slide gate G3 is located in the outlet cylinder section 34. These slide gates G1 to G3 open and close the corresponding cylinder sections to allow or block the flow of cargo.

[0041] Since each slide gate has a generally identical configuration, we will use the first slide gate G1 as an example for this explanation.

[0042] Figure 2 is a side cross-sectional view showing the first slide gate G1 when fully open. Figure 3 is a plan view showing the fixed gate member 37, which is a component of the first slide gate G1. Figure 4 is a plan view showing the movable gate member 38, which is a component of the first slide gate G1.

[0043] As shown in Figures 2 to 4, the first slide gate G1 comprises a fixed gate member 37 and a movable gate member 38. The fixed gate member 37 has a plurality of (five in the illustrated example) lattices 39 extending in a direction perpendicular to the axial direction, i.e., in the horizontal direction. These lattices 39 are arranged parallel to each other and extend to traverse the inside of the main cylinder portion 32. In this embodiment, a circular ring-shaped rim 40 is attached to the inner circumferential surface of the main cylinder portion 32, and both ends of each lattice 39 are fixed to this rim 40. However, the rim 40 may be omitted, and both ends of each lattice 39 may be directly fixed to the main cylinder portion 32. A total of several (six in the illustrated example) fixed slits 41 for passing the load B are formed between each lattice 39.

[0044] The upper surface of the lattice 39 is inclined to allow the load B that falls there to slide smoothly into the fixing slit 41, and is specifically formed in a mountain-shaped cross-section. In this embodiment, the cross-sectional shape of the lattice 39 is a home plate-shaped pentagon, and the lattice 39 has a solid structure. However, the configuration and shape of the lattice 39 are not limited to this, and for example, the lattice 39 may be formed from a plate material with an L-shaped cross-section (e.g., L-shaped steel) and arranged so that the upper surface is mountain-shaped.

[0045] The movable gate member 38 is formed from a flat plate material that is rectangular in plan view, and is superimposed on the lower surface of the fixed gate member 37 so as to be slidable in the front-rear direction as indicated by arrow f. The main cylinder portion 32 is provided with support members (not shown) that slidably support the left and right side edges of the movable gate member 38. The movable gate member 38 has a plurality of (six in the illustrated example) movable slits 42 that fully open the fixed slit 41 when the first slide gate G1 is fully open. Between the movable slits 42, there is a closing portion 43 that fully closes the fixed slit 41 when the first slide gate G1 is fully closed.

[0046] The lattice 39, fixed slit 41, movable slit 42, and closing part 43 extend in a direction perpendicular to the sliding direction f.

[0047] The width W1 of the movable slit 42 in the sliding direction f is equal to the width W2 of the fixed slit 41. The width W3 of the closing portion 43 is also equal to the width W4 of the lattice 39. In this embodiment, W1=W2=W3=W4. However, these dimensions can be set arbitrarily.

[0048] The first slide gate G1 is equipped with an actuator 44, such as a hydraulic cylinder, that drives the movable gate member 38. This actuator 44 is electrically connected to a control device E. When the actuator 44 operates according to a command from the control device E, the movable gate member 38 slides in the sliding direction f, and is opened and closed.

[0049] Figures 5 and 6 are a plan view and a side cross-sectional view showing the first slide gate G1 when fully open. At this time, the fixed slit 41 and the movable slit 42 are aligned perfectly in the vertical or up-and-down direction with the same width, and the fixed slit 41 is completely opened by the movable slit 42. Also at this time, the lattice 39 and the closing part 43 are aligned perfectly in the vertical or up-and-down direction with the same width.

[0050] Figure 7 is a side cross-sectional view showing the first slide gate G1 when it is half-open or at an intermediate opening. At this time, the movable gate member 38 slides further back (or forward) than when it is fully open. A portion of the fixed slit 41 in the width direction is opened by the movable slit 42, but the remaining portion of the fixed slit 41 is closed by the closing part 43 or the movable gate member 38, so the fixed slit 41 is in a half-open state.

[0051] Figure 8 is a side cross-sectional view showing the first slide gate G1 when fully closed. At this time, the movable gate member 38 slides further to the rear than when it is half-open. The closing part 43 is aligned perfectly with the fixed slit 41 in the vertical direction with the same width, and the fixed slit 41 is completely closed by the closing part 43 or the movable gate member 38. At this time, the movable slit 42 is also aligned perfectly with the lattice 39 in the vertical direction with the same width.

[0052] When fully closed, the fixed slit 41 is completely closed, and the movable gate member 38 is brought into close contact with the fixed gate member 37 by suction. This reduces the gap between the fixed gate member 37 and the movable gate member 38, thereby suppressing air leakage through the first slide gate G1.

[0053] The first level sensor S1 is the 2 Slide gate G 2 It is located lower down, at a height position near that point. The second level sensor S2 is located at the second slide gate G 2 The third level sensor S3 is located at a higher position, near the same height. The third level sensor S3 is located at a height above the second level sensor S2 and below the input opening 35. The first to third level sensors S1 to S3 are composed of, for example, well-known paddle-type level sensors, and are turned on when load B is detected (when load B is at the height of the level sensor) and turned off when load B is not detected (when load B is not at the height of the level sensor). Note that the first to third level sensors S1 to S3 may be composed of sensors other than paddle-type level sensors.

[0054] The control device E is composed of a well-known control unit equipped with a CPU, memory, etc., and is electrically connected to the first to third level sensors S1 to S3 and the first to third slide gates G1 to G3.

[0055] The feed device 30 has a gate position sensor 45 for each slide gate to detect the actual position of the movable gate member 38. The gate position sensor 45 is configured, for example, by a well-known encoder. These gate position sensors 45 are also electrically connected to the control device E. Based on the signals from the gate position sensors 45, the control device E controls the position of the movable gate member 38 and, consequently, the opening degree of the slide gate.

[0056] Next, the operation of the unloader 100 and the feed device 30 will be explained.

[0057] As shown in Figure 1, during cargo handling operations of the unloader 100, the vacuum pump 4 is activated, and cargo B in the cargo hold K is sucked in through the nozzle 7. This sucked-in cargo B rises through the vertical pipe 10 and reaches the horizontal pipe 6 through the curved pipe 9. It then moves through the horizontal pipe 6 and is fed into the receiver tank 2 through the input port 35.

[0058] After that, load B passes through the dispensing device 30, at which point the flow rate of load B is controlled. Load B discharged from the dispensing device 30 is sent to the ground conveyor 17 via the chute 14, the in-machine conveyor 15, and the ground chute 16.

[0059] Inside the receiver tank 2, the load B introduced from the inlet 35 falls as indicated by arrow g, and the airflow rises as indicated by arrow h, separating the load B from the airflow. The rising airflow passes through the bag filter 13, where any dust contained in the airflow is filtered out. After this, the airflow reaches the vacuum pump 4 and is released into the atmosphere through the exhaust pipe.

[0060] During these cargo handling operations, the first to third slide gates G1 to G3 are controlled by the control device E as follows. An example of the control is described below.

[0061] Figure 9 is a flowchart showing the normal operation and control of the dispensing device 30. The symbol Sn (where n is an integer) represents the step number. Here, we assume that the initial state (S0) is one in which the receiver tank 2 is empty (no load B), and therefore the first to third level sensors S1 to S3 are off, and the first to third slide gates G1 to G3 are fully closed.

[0062] From this initial state, the cargo handling operation begins, and when cargo B is supplied into the receiver tank 2, cargo B accumulates on the second slide gate G2 inside the receiver tank 2. First, the second level sensor S2 turns on (S1), and then the third level sensor S3 turns on (S2).

[0063] Then the second slide gate G2 is fully opened (S3). As a result, the load B that was accumulated on the second slide gate G2 passes through the second slide gate G2 and falls, accumulating on the first slide gate G1. Also, the level of load B decreases, the third level sensor S3 turns off (S4), and the second level sensor S2 turns off (S5).

[0064] Subsequently, the level of load B accumulated on the first slide gate G1 rises, the first level sensor S1 turns on (S6), and the second level sensor S2 turns on (S7).

[0065] Then, the first and second slide gates G1 and G2 are opened halfway, and the third slide gate G3 is opened fully (S8). As a result, the load B that had been accumulated on the first slide gate G1 falls little by little, passes through the third slide gate G3, and is sent to the chute 14 and the in-machine conveyor 1. In this way, the load B is discharged from the dispensing device 30 with the flow rate controlled to be approximately constant. The openings of the first and second slide gates G1 and G2 are set so that the supply flow rate of load B to the dispensing device 30 and the discharge flow rate of load B from the dispensing device 30 are approximately equal.

[0066] As a result, the level of load B decreases, and the second level sensor S2 turns off (S9).

[0067] Subsequently, if the discharge flow rate is greater than the supply flow rate, the level of load B decreases and the first level sensor S1 turns off (S10). In response, the first slide gate G1 is fully closed (S11). This stops the discharge of load B, the level of load B accumulated in the first slide gate G1 rises, and the first level sensor S1 turns on (S12).

[0068] Subsequently, when the second level sensor S2 is turned on (S7), step S8 is repeated. In this way, the level of load B is maintained so as not to fall below the second slide gate G2 as possible.

[0069] On the other hand, if the supply flow rate is greater than the discharge flow rate after step S9, the second level sensor S2 is turned on (S13). In response, the first slide gate G1 is fully opened (S14). This increases the discharge flow rate of load B and decreases the level of load B accumulated in the first slide gate G1.

[0070] After that, when the second level sensor S2 turns off (S15), the process returns to step S8, and the first slide gate G1 is returned to its original half-open state.

[0071] Thus, in this embodiment, the level of load B is maintained between the first level sensor S1 and the second level sensor S2 during the discharge of load B. That is, at least the space in the receiver tank 2 between the first slide gate G1 and the first level sensor S1 is filled with load B. Therefore, the filled load B can substantially seal the receiver tank 2, preventing air leakage from the atmospheric side (below the filled load B) to the vacuum side (above the filled load B). Thus, compared to conventional unloaders using rotary feeders, the gap can be reduced (substantially eliminated), the amount of leaked air can be reduced (substantially eliminated), and efficiency (e.g., the energy efficiency of the unloader) can be improved.

[0072] Furthermore, gap adjustment is not required for each slide gate G1 to G3. Therefore, the need for gap adjustment work can be eliminated, reducing the frequency of maintenance. This also significantly reduces the burden of maintenance.

[0073] Incidentally, the first to third slide gates G1 to G3 of this embodiment have a structure that minimizes air leakage when fully closed. On the other hand, when the first slide gate G1 or the second slide gate G2 is fully closed, their movable gate members 38 may be attracted to the fixed gate member 37, increasing sliding resistance and potentially preventing the movable gate members 38 from sliding. Therefore, in this embodiment, a diagnostic recovery control is performed by the control device E to address this situation.

[0074] Figure 10 is a flowchart showing the contents of the diagnostic recovery control. Diagnostic recovery control is performed individually for the first slide gate G1 and the second slide gate G2. An example for the first slide gate G1 is shown here, but the same applies to the second slide gate G2. Here, we assume that the initial state (S20) is when the first slide gate G1 is fully closed and the third slide gate G3 is fully open.

[0075] The control device E sends an open command to the first slide gate G1 (S21). The open command is a command signal to open the first slide gate G1. There are no limitations on the degree of opening after the opening operation; it may be half-open or fully open.

[0076] Subsequently, the control device E determines whether the first slide gate G1 has actually opened based on the signal from the gate position sensor 45 corresponding to the first slide gate G1 (S22). That is, the control device E detects the actual position of the movable gate member 38 after the open command from the signal from the gate position sensor 45 and determines whether the opening degree corresponding to that position is equal to the commanded opening degree.

[0077] The control device E terminates when the first slide gate G1 actually opens. However, if it does not actually open, the movable gate member 38 is expected to be attracted by negative pressure.

[0078] Therefore, in this case, the control device E completely closes the third slide gate G3 (S23). When this is done, the third slide gate G3 above By creating negative pressure on the side, the 1 Slide gate G 1 This reduces the pressure difference between the upper and lower parts. As a result, it becomes possible to release the suction of the movable gate member 38 and operate the movable gate member 38.

[0079] Subsequently, the control device E sends an open command to the first slide gate G1 again (S24). Then, the control device E determines again whether or not the first slide gate G1 has actually opened (S25).

[0080] If the control device E determines that the gate has actually opened, it fully opens the third slide gate G3 (S26) and terminates.

[0081] On the other hand, if the control device E determines that the opening operation did not actually occur, it assumes that some kind of malfunction has occurred, and activates a warning device (warning light, alarm, etc.) (not shown) (S27) and then terminates. At this time, the vacuum pump 4 or the unloader 100 may also be stopped.

[0082] As described above, the diagnostic and recovery control of this embodiment makes it possible to diagnose whether or not a temporary abnormality due to suction has occurred in the first slide gate G1 and the second slide gate G2, and if it has occurred, it can be immediately resolved and restored. Therefore, it is possible to ensure the stable operation of the unloader 100.

[0083] Diagnostic recovery control is preferably performed in conjunction with the main control shown in Figure 9. However, it may also be performed independently of the main control.

[0084] Although embodiments of the present disclosure have been described in detail above, various embodiments and modifications of the present disclosure are conceivable. (1) For example, in the first to third slide gates G1 to G3, the fixed gate member 37 may have a grid instead of multiple lattices 39. Also, in the above embodiment, the fixed slit 41 and the movable slit 42 were rectangular or substantially rectangular in shape when viewed from above, but they may have other shapes such as circles. (2) In the above embodiment, the level of load B was kept between the first level sensor S1 and the second level sensor S2, but instead, it may be kept between the second level sensor S2 and the third level sensor S3. (3) A simplified embodiment is also possible in which at least one of the third slide gate G3 and the third level sensor S3 is omitted.

[0085] The embodiments of this disclosure are not limited to those described above, but include any variations, applications, and equivalents encompassed within the spirit of this disclosure as defined by the claims. Therefore, this disclosure should not be constrained, but can be applied to any other art that falls within the scope of the spirit of this disclosure. [Explanation of symbols]

[0086] 2 Receiver Tanks 31 Exit section 100 Pneumatic Unloader B cargo E Control device G1 First Slide Gate G2 2nd Slide Gate G3 3rd Slide Gate S1 First level sensor S2 Second level sensor S3 Third-level sensor

Claims

1. A receiver tank for storing the sucked-in load, The outlet of the receiver tank is provided with a first slide gate and a second slide gate arranged in series from below, A first level sensor for detecting the presence or absence of a load at a predetermined height position between the first slide gate and the second slide gate, A second level sensor for detecting the presence or absence of a load at a predetermined height position above the second slide gate, A control device that controls the first slide gate and the second slide gate based on the detection results of the first level sensor and the second level sensor, Equipped with, During cargo handling operations, the control device controls the first slide gate and the second slide gate so as to fill the space in the receiver tank between the first slide gate and the first level sensor with cargo. During cargo handling operations, the control device will When the first slide gate is fully closed and the second slide gate is fully open, and the second level sensor detects that there is a load, the first slide gate and the second slide gate are controlled to a half-open state. Subsequently, after the second level sensor detects that there is no load, When the first level sensor detects that there is no load, the first slide gate is controlled to be fully closed. When the second level sensor detects the presence of a load, the first slide gate is controlled to be fully open. A pneumatic unloader characterized by the following features.

2. A third level sensor is provided for detecting the presence or absence of a load at a predetermined height position above the second level sensor. The control device also controls the first slide gate and the second slide gate based on the detection result of the third level sensor. The pneumatic unloader according to claim 1.

3. It includes a third slide gate located below the first slide gate. The pneumatic unloader according to claim 1.

4. If the control device sends an open command to the fully closed first slide gate or the second slide gate, but the first slide gate or the second slide gate does not open, the control device will fully close the third slide gate. The pneumatic unloader according to claim 3.

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