In-tank pressure control device for granule pneumatic transportation device, and control method therefor

Abstract

To provide: an in-tank pressure control device for a granule pneumatic transportation device, which is capable of automatically avoiding pressure rise even when in-tank pressure rises during receiving of granules; and a control method therefor.SOLUTION: An in-tank pressure control device 40 for a granule pneumatic transportation device according to the present invention comprises: a pressure sensor 42 for measuring inner pressure of two or more tanks 11, 12 included in a granule pneumatic transportation device 10 after closing a receiving valve 20 and an exhaust valve 22 after it is completed to receive granules in one of the tanks of the granule pneumatic transportation device; and a control unit 44 for performing control by which the inner pressure of the tanks is made to be an in-tank pressure specified value or less by opening the exhaust valve when exceeding the in-tank pressure specified value to which a measured value of the pressure sensor is predetermined via electrical connection of the pressure sensor, and the receiving valve and the exhaust valve of the granule pneumatic transportation device.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention particularly relates to an apparatus and method for controlling pressure within a tank of a powder / granular material pneumatic transport apparatus for continuously transporting powder / granular material from a plurality of tanks in a batchwise manner. [Background technology]

[0002] There is a powder pneumatic conveying device with good conveying efficiency as a means for conveying a large amount of powder (for example, as disclosed in Patent Document 1). In this powder pneumatic conveying device, a receiving valve is installed at the top of a tank, and when the powder is received, the receiving valve is opened to receive the powder into the tank. After the powder is received up to a preset amount, the receiving valve is closed to stop the outflow into the tank. Next, the powder pressure valve installed at the bottom of the tank is opened, compressed air is supplied into the tank, and the pressure inside the tank is increased by the resistance inside the transport pipe connected to the tank. The powder is conveyed to the outside of the tank via the transport pipe while maintaining the pressure inside the tank at a specified pressure during conveying. The conveying principle of the device is to outflow (send) the mixture of high-pressure air and powder inside the tank to a supply destination where the pressure inside the tank is lower than the pressure inside the tank by utilizing the pressure difference. This outflow is generally a batch type, and a pair of twin-drum type and two-way switching valve are often used for two tanks, and the supply and discharge work is performed almost automatically and continuously by repeating the receiving and conveying alternately.

[0003] In such powder pneumatic transport equipment, if the powder generates heat due to incineration ash or if the valves deteriorate over time and pressure leaks from the compressor, the pressure inside the tank will rise after the powder is replenished. This can cause the powder to get caught in the two-way selector valve when switching between pressure feeding and receiving with the twin-drum type, resulting in damage. Normally, the pressure inside the tank does not rise when receiving, but it can rise when air is used for discharging upstream. Conventionally, if the pressure inside the tank rises during receiving, the gate is manually throttled. When receiving is completed, the receiving valve is closed, and then the exhaust valve is manually closed after a certain period of time has passed, which places a heavy burden on on-site workers. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 4-71809 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the problems of the conventional technology described above, the problem to be solved by the present invention is to provide an internal pressure control device for a powder / granular material pneumatic transport device and a control method thereof, which can automatically prevent a pressure increase in the tank even if the pressure increases when powder / granular material is received. [Means for solving the problem]

[0006] As a first means for solving the above problems, the present invention provides a powder / granular material pneumatic transport device having two or more tanks, the device including a pressure sensor for measuring an internal pressure of the tank after the tank has completed receiving powder / granular material and the receiving valve and the exhaust valve are closed; The object of the present invention is to provide an internal pressure control device for a powder / granular material pneumatic transport device, which is characterized in that it is equipped with a control unit that is electrically connected to the pressure sensor, and to the receiving valve and exhaust valve of the powder / granular material pneumatic transport device, and that opens the exhaust valve when the measurement value of the pressure sensor exceeds a predetermined internal pressure value, thereby controlling the internal pressure of the tank to be equal to or lower than the internal pressure value of the tank. According to the first means, even if the pressure in the tank rises when powder or granular material is received, the pressure rise can be automatically prevented. In addition, damage and deterioration of the two-way switching valve caused by the pressure rise in the tank when powder or granular material is received can be prevented, and the life of the entire device can be extended.

[0007] As a second means for solving the above-mentioned problems, the present invention provides an internal pressure control device for a powder / granular material pneumatic transport device, which is characterized in that in the first means, the control unit plots the measurement values ​​of the pressure sensor over time, and when the increase in the internal pressure per unit time exceeds a set value, opens the exhaust valve to control the internal pressure of the tank to be equal to or lower than the specified internal pressure value of the tank. According to the second means described above, even before the measured value exceeds the specified value for the internal pressure, it is possible to predict that the specified value will be exceeded from the increase in internal pressure per unit time, and to quickly control the internal pressure.

[0008] As a third means for solving the above problems, the present invention provides a method for measuring an internal pressure of a tank of a powder / granular material pneumatic transport device having two or more tanks after the tank has completed receiving powder / granular material and the receiving valve and the exhaust valve are closed, The object of the present invention is to provide a method for controlling pressure inside the tank of a powder / granular material pneumatic transport device, comprising a step of controlling the internal pressure of the tank to be equal to or lower than the specified internal pressure value by opening the exhaust valve when the measurement value of the pressure sensor exceeds a predetermined specified internal pressure value. According to the third means, even if the pressure in the tank rises when powder or granular material is received, the pressure rise can be automatically prevented. Also, damage and deterioration of the two-way switching valve caused by the pressure rise in the tank when powder or granular material is received can be prevented, and the life of the entire device can be extended.

[0009] As a fourth means for solving the above-mentioned problems, the present invention provides a method for controlling pressure inside a tank of a powder / granular material pneumatic transport device, which is characterized in that, in the third means, it further comprises a step of plotting the measurement values ​​of the pressure sensor over time, and when an increase in the internal pressure per unit time exceeds a set value, opening the exhaust valve to control the internal pressure of the tank to be equal to or lower than the specified internal pressure value. According to the fourth means described above, even before the measured value exceeds the specified value for the internal pressure, it is possible to quickly control the internal pressure by predicting that the specified value will be exceeded from the increase in internal pressure per unit time. Effect of the Invention

[0010] According to the present invention, even if the pressure in the tank rises when powder or granular material is received, the pressure rise can be automatically prevented. In addition, damage and deterioration of the two-way switching valve caused by the pressure rise in the tank when powder or granular material is received can be prevented, and the life of the entire device can be extended. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing the configuration of an internal pressure control device of a powder / granular material pneumatic transport device of the present invention. [Diagram 2] FIG. 2 is a flow diagram of a method for controlling pressure inside a tank of a powder / granular material pneumatic transport device according to the present invention. [Diagram 3] 1 is a graph showing the relationship between the pressure inside the tank and time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an internal pressure control device for a powder / granular material pneumatic transport device and a control method thereof according to the present invention will be described in detail below with reference to the drawings.

[0013] [In-tank pressure control device 40 for powder and granular material pneumatic transport device] FIG. 1 is a schematic diagram of the internal pressure control device of the powder pneumatic conveying device of the present invention. In the powder pneumatic conveying device 10, two tanks (two in FIG. 1-2, also called tanks) 11, 12 are arranged in parallel, and each tank is equipped with an air supply pipe 14 for high-pressure air from a compressor 13. Two or more tanks may be installed. A two-way switching valve 16 is installed between the tanks, and the powder in the tank can be discharged to the outside through a transport pipe 17 connected to the valve. Each tank is equipped with multiple valves. The receiving valve 20 installed at the top of the tank is a valve that feeds the powder (raw material) from the silo / hopper 18 into the tank. Similarly, the exhaust pipe 21 and exhaust valve 22 installed at the top of the tank are connected to the silo / hopper 18 to reduce the pressure inside the tank. The exhaust pipe 21 is connected to an exhaust pipe purge valve 24 connected to the air supply pipe 14, and the exhaust pipe 21 can be purged with high-pressure air. A ring nozzle 25 is installed in the tank, and high-pressure air is sprayed onto the powder in the tank via a ring nozzle pressure-feed valve 26. A ring nozzle exhaust valve 27 scavenges the ring nozzle 25. In addition, a main nozzle pressure-feed valve 28 and an auxiliary pressure-feed valve 29 spray high-pressure air onto the powder to force it through.

[0014] The tank pressure control device 40 of the powder / granular material pneumatic transport device is equipped with a pressure sensor 42 and a control unit 44. The pressure sensor 42 is a sensor that measures the pressure (internal pressure) inside the tank. As mentioned above, if the powder / granular material generates heat due to incineration ash or the pressure from the compressor 13 leaks due to aging of the valves, the pressure inside the tank will rise when the powder / granular material is replenished into the tank. The pressure sensor 42 measures the internal pressure of the tank after the powder / granular material is received and the receiving valve 20 and exhaust valve 22 are closed. The pressure sensor 42 can measure the amount of powder / granular material in the tank from the pressure inside the tank. The control unit 44 is a PLC (Programmable Logic Controller) that is electrically connected to the pressure sensor 42, the exhaust valve 22, and the exhaust pipe purge valve 24, and controls the opening and closing of each valve based on the measured values ​​of the sensors. The control unit 44 specifically controls the flow shown in Fig. 2. At this time, the control unit 44 predetermines a specified value for the pressure inside the tank. The specified value for the pressure inside the tank is a specified value determined by the specifications of the tank and various valves, and is a value set to an internal pressure that the accessories can mechanically withstand without being damaged when pressure is generated inside the tank.

[0015] [Method for controlling pressure inside a tank of a powder / granular material pneumatic conveying device] The control method for the tank pressure control device of the powder pneumatic transport apparatus of the present invention having the above-mentioned configuration will be described below. Fig. 2 is a flow chart of the tank pressure control method for the powder pneumatic transport apparatus of the present invention. The powder / granular material pneumatic transport device shown in the figure is a batch type equipped with two tanks (tank A and tank B). As an example, we will explain the method of controlling the pressure inside the tanks when powder / granular material is received in tank A and discharged from tank B. (Step 1) The receiving valve 20 and exhaust valve 22 of tank A are opened to start receiving the powder and granular material. (Step 2) Powder and granular materials are added to tank A (load addition). (Step 3) The amount of powder or granules is measured from the pressure inside the tank using pressure sensor 42, and the powder or granules are continued to be added until the tank is filled to capacity. (Step 4) After the tank is filled, the receiving valve 20 and the exhaust valve 22 are closed.

[0016] (Step 5) The internal pressure of tank A is measured by the pressure sensor 42, and the control unit 44 determines whether or not the internal pressure is equal to or lower than a predetermined tank internal pressure value. (Step 6) If the answer is Yes, the internal pressure of tank A is equal to or lower than the tank internal pressure stipulation value, and therefore the receiving is completed. (Step 7) If the answer is No, the internal pressure of tank A is higher than the specified internal tank pressure value, so the exhaust valve 22 is opened, or the exhaust valve 22 and the exhaust pipe purge valve 24 are opened to reduce the pressure inside the tank. When the exhaust valve 22 is opened, the pressure inside the tank can be reduced. When the exhaust valve 22 and the exhaust pipe purge valve 24 are opened, in addition to reducing the pressure inside the tank, the exhaust pipe 21 can be scavenged. (Step 8) The internal pressure of tank A is again measured by the pressure sensor 42, and the control unit 44 determines whether it is equal to or lower than the predetermined internal tank pressure value. If the result is No, the internal pressure of tank A is higher than the internal tank pressure value, so the process returns to step 7 and the exhaust valve 22 and exhaust pipe purge valve 24 are opened. (Step 9) If Yes, the internal pressure of tank A is equal to or lower than the specified internal tank pressure value, so close the exhaust valve 22 and the exhaust pipe purge valve 24, proceed to step 6, and the receiving is completed. (Step 10) While the powder is being received in tank A, the powder is being discharged from tank B. The tank A side of the two-way switching valve 16 is closed, and the tank B side is opened.

[0017] (Step 11) The main nozzle pressure feed valve 28 and the ring nozzle pressure feed valve 26 are opened. (Step 12) The powder and granular materials in tank B are discharged to the outside (being pumped). (Step 13) The amount of powder or granules is measured from the pressure inside the tank by the pressure sensor 42, and when the powder or granules have been dispensed, the pressure transfer is complete. (Step 14) Close the main nozzle pressure feed valve and the ring nozzle pressure feed valve 26, and proceed to step 6. (Step 15) Next, in order to receive the powder and granular materials in tank B and discharge the powder and granular materials in tank A, the tank A side of the two-way switching valve is opened and the tank B side is closed. (Step 16) The powder is pumped from tank A (steps 10-14) and the powder starts to be received in tank B (steps 1-9). Similar operations are then repeated.

[0018] FIG. 3 is a graph showing the relationship between the tank pressure and time. In this graph, the vertical axis indicates the tank pressure (MPa) and the horizontal axis indicates the elapsed time (s). The control unit 44 may plot the measured values ​​of the pressure sensor 42 over time, and when the increase in the tank pressure per unit time exceeds a set value, the control unit 44 may open the exhaust valve 22 to control the tank pressure to be equal to or lower than the tank pressure set value. The set value of the increase in the tank pressure is set to a value that is likely to cause damage to the two-way switching valve 16 by powder being caught in the two-way switching valve 16 if the pressure from the compressor side is clearly leaking into the tank due to valve damage, etc., and the receiving valve 20 and the exhaust valve 22 are closed and the two-way switching valve 16 is opened in this state. This makes it possible to quickly control the internal pressure by predicting that the internal pressure will exceed the specified value from the increase in internal pressure per unit time, even before the measured value exceeds the specified value for internal pressure.

[0019] According to the present invention, even if the pressure in the tank rises when powder or granular material is received, the pressure rise can be automatically prevented. Also, damage and deterioration of the two-way switching valve caused by the pressure rise in the tank when powder or granular material is received can be prevented, and the frequency of maintenance can be reduced, thereby extending the life of the entire device. Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications can be made without departing from the spirit and scope of the present invention. Furthermore, the present invention is not limited to the combinations shown in the embodiments, but can be implemented in various combinations. [Explanation of symbols]

[0020] 10. Powder and granular material pneumatic conveying equipment 11, 12 tanks 13. Compressor 14 Air supply pipe 16 Two-way valve 17 Transport pipe 18 Silo Hopper 20 Receiving valve 21 Exhaust pipe 22 Exhaust valve 24 Exhaust pipe purge valve 25 Ring Nozzle 26 Ring nozzle pressure valve 27 Ring nozzle exhaust valve 28 Main nozzle pressure valve 29 Auxiliary pressure valve 40 Pressure control device in a tank for a powder / granular material pneumatic conveying device 42 Pressure Sensor 44 Control section

Claims

1. a pressure sensor for measuring an internal pressure of one of two or more tanks of a powder / granular material pneumatic transport device after the receiving valve and the exhaust valve are closed upon completion of receiving the powder / granular material into the tank; a control unit electrically connected to the pressure sensor, and to the receiving valve and exhaust valve of the powder / granular material pneumatic transport device, and configured to open the exhaust valve when the measurement value of the pressure sensor exceeds a predetermined tank pressure specified value, thereby controlling the internal pressure of the tank to be equal to or lower than the tank pressure specified value.

2. The tank pressure control device of the powder / granular material pneumatic transport device according to claim 1, The control unit plots the measurement values ​​of the pressure sensor over time, and when an increase in the internal pressure per unit time exceeds a set value, opens the exhaust valve to control the internal pressure of the tank to be equal to or lower than the specified internal pressure value.

3. a step of measuring an internal pressure of one of two or more tanks of a powder / granular material pneumatic transport device with a pressure center after the receiving valve and the exhaust valve are closed upon completion of receiving the powder / granular material into the one of the tanks; A method for controlling pressure inside a tank of a powder / granular material pneumatic transport device, comprising the step of opening the exhaust valve to control the internal pressure of the tank to below a predetermined internal pressure value when the measurement value of the pressure sensor exceeds a predetermined internal pressure value.

4. A method for controlling pressure in a tank of a powder / granular material pneumatic transport device according to claim 3, comprising the steps of: a step of plotting the measured values ​​of the pressure sensor over time, and when an increase in the internal pressure per unit time exceeds a set value, opening the exhaust valve to control the internal pressure of the tank to be equal to or lower than the specified internal pressure value of the tank.

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