Powder supply device

Abstract

The invention provides a technology capable of controlling the supply of a fixed amount of powder. The powder supply device is provided with: a storage unit for storing powder; a supply duct connected to the storage unit; a flexible nozzle disposed in the storage part and configured to spray air into the storage part so as to supply the air and the powder from the supply duct; a measuring unit that measures the weight of the storage unit; and a control unit that controls the injection time of the air injected by the nozzle on the basis of the weight measured by the measurement unit.

Description

Technical Field

[0001] This disclosure relates to a powder supply device. Background Technology

[0002] Patent Document 1 discloses an apparatus for supplying powder to a dust collector. The apparatus includes: a hopper for storing powder; a supply pipe for supplying the powder from the hopper to the dust collector; and a nozzle disposed within the hopper and having flexibility, for injecting air into the hopper. The nozzle's tip is a free end, which moves around within the hopper due to the reaction force of the injection, stirring the powder and causing it to become airborne. The airborne powder, along with the air, is supplied to the dust collector through the supply pipe. The powder supplied to the dust collector mixes with dust, reducing the flammability of the dust. The nozzle is controlled to inject air at a constant cycle for a constant time.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2008-100212

[0004] In the device described in Patent Document 1, the distance between the upper surface of the powder stored in the hopper and the nozzle varies depending on the amount of powder stored in the hopper. Therefore, in the device described in Patent Document 1, the amount of airborne powder varies depending on the amount of powder stored. Since the powder supply varies depending on the amount of powder stored in the hopper, there is a concern that the device described in Patent Document 1 may not be able to supply a fixed amount of powder to the dust collector. This disclosure provides a technique that can control the supply of a fixed amount of powder. Summary of the Invention

[0005] One aspect of the powder supply apparatus disclosed herein includes: a storage section for storing powder; a supply pipe connected to the storage section; a nozzle disposed within the storage section, having flexibility, for injecting air into the storage section to supply air and powder from the supply pipe; a measuring section for measuring the weight of the storage section; and a control section for controlling the injection time of the air injected by the nozzle based on the weight measured by the measuring section.

[0006] According to this disclosure, it is possible to control the supply of powder in quantitative quantities. Attached Figure Description

[0007] Figure 1 This is a schematic diagram illustrating an example of a dust collection system included in a powder supply device according to one embodiment.

[0008] Figure 2 (A) is a time graph showing the relationship between the control time of the solenoid valve, the powder weight, and the supply amount when the injection time is controlled to be constant. Figure 2 (B) is a time graph showing the relationship between the control time of the solenoid valve, the powder weight, and the supply amount when the injection time is varied for control.

[0009] Figure 3 It is a time graph showing the relationship between the control time of the solenoid valve, the measured weight of the force sensor, and the sampled weight.

[0010] Figure 4 This is a flowchart illustrating the powder supply method.

[0011] Figure 5 (A) is a graph showing the time variation of powder weight and the time variation of feed rate in the examples. Figure 5 (B) is a graph showing the time variation of powder weight and the time variation of feed rate in the comparative example.

[0012] Figure 6 This is a schematic diagram illustrating an example of a dust collection system provided in a powder supply device according to another embodiment.

[0013] Figure 7 It is a schematic diagram showing the end face of the injector.

[0014] Figure 8 This is a time graph showing the relationship between the control time of the solenoid valve, the measured weight of the force sensor, and the sampled weight in the powder supply device according to another embodiment.

[0015] Figure 9 This is a schematic diagram illustrating an example of a dust collection system included in a powder supply device according to another embodiment. Detailed Implementation

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same elements, and repeated descriptions are omitted. The scale of the drawings need not be consistent with the description. The terms "upper," "lower," "left," and "right" are used for convenience based on the illustrated states.

[0017] [Structure of the powder supply device]

[0018] Figure 1 This is a schematic diagram illustrating an example of a dust collection system included in a powder supply device according to one embodiment. (Example) Figure 1As shown, the dust collection system 100 includes a powder supply device 1 and a dust collector 2. The powder supply device 1 is used, for example, in a dust collector 2 installed in a factory or similar facility. The dust collector 2 uses a filter to capture airborne dust. Dust refers to fine particles small enough to float in the air, including fumes generated during laser processing, plasma processing, and welding. Filters can sometimes become charged due to the adhesion of charged dust particles or friction generated when dust particles come into contact with the filter. Static electricity can be a cause of ignition; therefore, inert powder is supplied to the dust collector 2 through the powder supply device 1, mixing the inert powder with the dust to reduce flammability.

[0019] The powder supply device 1 includes a hopper 10 (an example of a storage section). The hopper 10 stores powder P. Powder P is, for example, an inert powder. As a specific example, powder P is calcium carbonate or calcium hydroxide powder. The hopper 10 has a compressed air inlet 10a and an air outlet 10b. An air source 11 is connected to the compressed air inlet 10a via a pipe 12. Thus, compressed air is supplied from the air source 11 to the interior of the hopper 10 via the pipe 12.

[0020] The powder supply device 1 includes a nozzle 13 disposed within the hopper 10. The nozzle 13 is a cylindrical component and is flexible. The nozzle 13 is made of, for example, nylon, polyurethane, or silicone. The end of the nozzle 13 is connected to a compressed air inlet 10a, where compressed air is supplied. The front end of the nozzle 13 is a free end, which sprays compressed air into the hopper 10. At this time, the nozzle 13 moves irregularly within the hopper 10 under the reaction force of the spray (a so-called turbulent state), stirring the contents of the hopper 10. As a result, accumulated powder P is dispersed. Because the nozzle 13 is flexible, even powder accumulated in the corners of the hopper 10 can be dispersed. The dispersed powder P, along with the air, is discharged to the outside from the outlet 10b of the hopper 10.

[0021] The powder supply device 1 has a supply pipe 14 connected to the hopper 10. The end of the supply pipe 14 is connected to the outlet 10b of the hopper 10, and the front end is connected to the dust collector 2. The powder P stored in the hopper 10 is supplied to the dust collector 2 through the supply pipe 14.

[0022] A solenoid valve 15 is installed in piping 12. The solenoid valve 15 is controlled to open and close by a control unit 16. This changes the amount and timing of compressed air intake. The control unit 16 includes a PLC (Programmable Logic Controller) 161 and a signal converter 162. The PLC is a device that includes a processor, memory, display, input / output units, etc. The signal converter 162 is a device that converts sensor outputs, etc., into electrical signals, etc.

[0023] The control unit 16 controls the injection time of the air ejected by the nozzle 13 based on the weight of the hopper 10. The hopper 10 is supported by a force sensor 17 (an example of a measuring unit). The force sensor 17 outputs a sensor signal related to the weight of the hopper 10 to the control unit 16. The signal converter 162 of the control unit 16 converts the sensor signal from the force sensor 17 into a voltage signal, etc. The PLC 161 obtains the weight of the hopper 10 based on the voltage signal. The PLC 161 controls the opening and closing timing and duration of the solenoid valve 15 based on the measured weight of the hopper 10.

[0024] [Details of the Control Department's Operations]

[0025] Figure 2 (A) is a time graph showing the relationship between the control time of the solenoid valve, the powder weight, and the supply amount when the injection time is controlled to be constant. Figure 2 (B) is a time graph showing the relationship between the control time of the solenoid valve, the powder weight, and the supply amount when the injection time is varied for control.

[0026] like Figure 2 As shown in (A), when the injection time of the solenoid valve 15 is controlled to be constant by the control unit 16, powder P is supplied as time passes, thus reducing the powder weight (curve L1 in the figure). With the reduced accumulation of powder P in the hopper, the distance between the upper surface of the accumulated powder P and the nozzle increases, resulting in less airborne powder. Therefore, the supply rate per unit time (hereinafter also referred to as the supply speed) decreases over time, raising concerns that a fixed amount of powder P may not be supplied to the dust collector 2.

[0027] Therefore, the control unit 16 controls the injection time of the nozzle 13 to achieve a quantitative supply of powder P. A quantitative supply of powder P means that the amount of powder P supplied per unit time is constant. That is, a quantitative supply of powder P means that the supply rate of powder P is constant. Figure 2 As shown in (B), the control unit 16 sets a short spray time when the weight of powder P is large, and gradually increases the spray time as the weight of powder P decreases (the straight line L1 in the figure). Thus, as enclosed by the dotted line in the figure, a quantitative supply of powder P can be achieved.

[0028] The control unit 16 can also calculate the supply speed of powder P based on the weight of powder P before and after injection and the injection time, and compare the calculated supply speed with the target supply speed, thereby controlling the next injection time. The target supply speed is a value preset by the operator, etc. The control unit 16 records the measurement results of the force sensor 17 along with the time in the storage device. The control unit 16 records the injection time, i.e., the opening and closing time of the solenoid valve 15, along with the time in the storage device. Thus, the control unit 16 can use the weight of powder P before and after injection and the injection time for calculation, thereby calculating the supply speed. The control unit 16 determines the injection time so that the calculated supply speed is close to the target supply speed.

[0029] If the measured supply speed is greater than the target supply speed, the control unit 16 can also set the next injection time to be shorter than the current injection time by a predetermined time. The predetermined time is a time that is appropriately set. If the measured supply speed is less than or equal to the target supply speed, the control unit 16 can also set the next injection time to be longer than the current injection time by a predetermined time. The predetermined time is a time that is appropriately set. If the measured supply speed is within a predetermined range including the target supply speed, the control unit 16 can also use the current injection time as the next injection time without changing it. The predetermined range is a speed range that is appropriately set. By setting the predetermined range, the control unit 16 can control the supply to converge more easily to the target supply speed.

[0030] The control unit 16 can display the determined injection time, calculated supply speed, etc. on the display screen. Thus, the operator can confirm that the powder supply device 1 can quantitatively feed powder P.

[0031] Since powder P is lightweight, the weight variation of hopper 10 with each injection is small, sometimes falling below the measurable limit of force sensor 17. Therefore, control unit 16 can also measure the weight of hopper 10 in cycles of multiple injections. Furthermore, during powder P injection, nozzle 13 moves around due to reaction force, raising concerns that the measurement results of force sensor 17 may contain noise. Therefore, control unit 16 can also stop the injection of air using nozzle 13 while force sensor 17 is measuring the weight of hopper 10. The period during which force sensor 17 measures the weight of hopper 10 refers to the period during which data is sampled, which is the measurement time of force sensor 17.

[0032] Figure 3 This is a time graph showing the relationship between the control time of the solenoid valve, the measured weight of the force sensor, and the sampled weight. For example... Figure 3 As shown, the control unit 16 can also perform multiple injections according to the determined injection time. Figure 3In the example shown, a total of four injections are performed in cycle T1. Cycle T1 includes an injection period t1 and a stop period t2. During the injection period t1, the nozzle 13 moves around, so the measurement of the force sensor 17 includes noise. During the stop period t2, the nozzle 13 stops, so the measurement of the force sensor 17 does not include noise. Therefore, the control unit 16 samples the data output during the stop period t2 and averages the sampled data, thereby setting the weight measured in the measurement cycle T2, which includes four cycles T1. The sampled weight W is determined for each measurement cycle SY, which is the measurement cycle T2 plus the calculation time T3. n For example, in the previous measurement cycle, the sample weight was W. n-1 In the next measurement cycle, the sample weight becomes W. n+1 Control unit 16 via, for example Figure 3 The operation shown can reduce the noise generated by nozzle 13 while properly capturing the weight change of powder P.

[0033] [Operation of the powder supply device (powder supply method)]

[0034] Figure 4 This is a flowchart illustrating the powder supply method. The process begins from the control unit 16 when powder P is filled into hopper 10 and an operator's work instruction is received. Figure 4 The flowchart shown.

[0035] As in step S10, the control unit 16 measures the initial weight of the hopper 10. The control unit 16 measures the weight of the hopper 10 based on the signal from the force sensor 17. Next, as in step S12, the control unit 16 causes the solenoid valve 15 to open a predetermined number of times and for a predetermined period of time. As a result, compressed air is blown into the hopper 10, and the compressed air and powder P are fed from the hopper 10 into the dust collector 2.

[0036] Next, as step S14, the control unit 16 measures the weight of the hopper 10. The control unit 16 measures the weight of the hopper 10 based on the signal from the force sensor 17. Then, as step S16, the control unit 16 calculates the difference (weight difference) between the initial weight measured in step S10 and the weight measured in step S14. Then, the control unit 16 calculates the feeding rate based on the weight difference (absolute value). As a specific example, the control unit 16 calculates the feeding rate by dividing the weight difference by the feeding time.

[0037] Next, as step S18, the control unit 16 determines whether the supply speed calculated in step S16 is greater than the target supply speed. If it is determined that the calculated supply speed is greater than the target supply speed (step S18: Yes), as step S20, the control unit 16 reduces the next injection time. If it is determined that the calculated supply speed is not greater than the target supply speed (step S18: No), as step S22, the control unit 16 increases the next injection time.

[0038] If step S20 or step S22 has ended, the control unit 16 determines whether the termination condition has been met. The termination condition is the condition for stopping the powder supply and is preset by the operator, etc. For example, the termination condition includes receiving a termination instruction from the operator, reaching a designated time, or the dust collector 2 stopping. If the termination condition is determined not to be met (step S24: No), the process returns to step S12 and repeats the process from step S12 to step S24. If the termination condition is determined to be met (step S24: Yes), Figure 4 The flowchart shown ends here.

[0039] [Summary of Implementation Methods]

[0040] In the powder supply device 1, powder P in the hopper 10 is atomized by a flexible nozzle 13 disposed within the hopper 10 and fed into the dust collector 2 along with air through the supply pipe 14. The weight of the hopper 10 is measured by a force sensor 17. The injection time of the air ejected by the nozzle 13 is controlled based on the measured weight. Since the powder supply device 1 can control the air injection time according to the weight of the hopper 10, it can control the supply of a fixed amount of powder P to the dust collector 2.

[0041] [Variation Example]

[0042] The above describes various exemplary embodiments, but is not limited to the exemplary embodiments described above. Various omissions, substitutions and changes can also be made.

[0043] For example, in one embodiment, a powder supply device 1 is shown with two nozzles, but it may also have one nozzle, or even three or more nozzles. Alternatively, it may be configured such that the number of nozzles at the front end is greater than the number at the back end by branching the nozzles from the middle.

[0044] The control unit 16 only needs to be able to process the sensor output and control the spraying time of the nozzle 13, and is not limited to a PLC and signal converter. The control unit 16 can, for example, be configured as a computer system including memory such as a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory), input / output devices such as a touch panel, mouse, keyboard, and display, and communication devices such as a network card. The control unit 16 can control the flow rate and pressure of the air sprayed by the nozzle 13.

[0045] In this embodiment, an example of measuring the weight of the hopper 10 using a force sensor 17 is shown. However, the hopper 10 can also be supported by an elastic body such as a spring (other examples of the measuring unit) to measure the weight. Alternatively, the weight of the powder can be directly measured by a sensor such as an image sensor disposed within the hopper 10 (other examples of the measuring unit), and the weight of the hopper 10 can be added to the weight of the empty hopper 10 to measure the weight of the hopper 10. That is, "measuring the weight of the hopper 10" includes directly measuring the weight of the powder.

[0046] The powder supply device 1 can also be applied, for example, to a duct for conveying dust in the air, such as in a factory. The powder supply device 1 is connected to the duct to replace the dust collector 2. If dust accumulates in the duct, it can become a cause of fire due to static electricity. Therefore, by supplying inert powder into the duct through the powder supply device 1, the inert powder mixes with the dust, thereby reducing the flammability.

[0047] [Evaluation of supply speed]

[0048] The following describes an embodiment using the powder supply device 1 for evaluating the supply speed. However, this disclosure is not limited to these embodiments.

[0049] (Example)

[0050] Powder P was fed into dust collector 2 using powder supply device 1. After passing through... Figure 3 Sampling is performed as shown to improve the accuracy of the weight of hopper 10, while... Figure 2 Quantitative control was performed as shown in (B). The conditions are as follows.

[0051] Powder P: Calcium carbonate powder

[0052] Period T1: 30 seconds

[0053] Cycle SY measured: 180 seconds

[0054] Target supply rate TP: 0.1 g / s

[0055] (Comparative Example)

[0056] Powder P was fed into dust collector 2 using powder supply device 1. After passing through... Figure 3 Sampling is performed as shown to improve the accuracy of the weight of hopper 10, while... Figure 2 The injection time was set to a constant time as shown in (A). Other conditions were the same as in the embodiment.

[0057] Figure 5 (A) is a graph showing the time variation of powder weight and the time variation of feed rate in the examples. Figure 5 (B) is a graph showing the time variation of powder weight and feed rate in the comparative example. For example... Figure 5 (A) and Figure 5 As shown in (B), it was confirmed that the powder weight of both the examples and the comparative examples decreased over time, decreasing by approximately 6 kg from the start of the apparatus until 20 hours had elapsed. Furthermore, as... Figure 5 As shown in (A), in the powder supply apparatus of the embodiment, it was confirmed that the supply rate of powder P was maintained at a value close to the target supply rate TP during the period from device startup to 20 hours. In contrast, in the powder supply apparatus of the comparative example, the supply rate was 2 to 3 times the target supply rate TP during the period from device startup to several hours, the supply rate was greater than the target supply rate TP during the period from device startup to 10 hours, and the supply rate was less than the target supply rate TP during the period from 10 hours to 20 hours. In this way, it was confirmed that the powder supply apparatus 1 of the embodiment can be controlled to supply a fixed amount of powder.

[0058] The following is for reference Figure 6 , Figure 7 and Figure 8 The powder supply device according to another embodiment will be described. Figure 6 This is a schematic diagram illustrating an example of a dust collection system provided in a powder supply device according to another embodiment. Figure 6 The powder supply device 1A shown has a supply pipe 14A instead of a supply pipe 14. Hereinafter, the powder supply device 1A will be described with a focus on the differences between the powder supply device 1A and the powder supply device 1, and repeated descriptions will be omitted.

[0059] The powder supply device 1A also includes a housing 18. A solenoid valve 15 and a control unit 16 are disposed within the housing 18. A force sensor 17 is disposed on the housing 18. In the powder supply device 1A, the housing 18, the force sensor 17, and the hopper 10 are arranged sequentially from bottom to top.

[0060] The supply duct 14A has an ejector 20. The ejector 20 uses compressed air to generate an airflow from the powder supply device 1A to the dust collector 2. Figure 6 In the example shown, the supply pipe 14A also has a first pipe 20a and a second pipe 20b. The first pipe 20a connects the outlet 10b of the hopper 10 to the ejector 20. The second pipe 20b connects the ejector 20 to the dust collector 2. The ejector 20 is configured to spray a drive flow into the second pipe 20b. The ejector 20 can be fixed to the housing 18.

[0061] Figure 7 This is a schematic diagram showing the end face of the injector. (For example...) Figure 7 As shown, the ejector 20 includes a suction section 21, a supply section 22, and an air nozzle 23. The suction section 21 is connected to the hopper 10. For example, the suction section 21 is connected to the hopper 10 via a first pipe 20a. The supply section 22 is configured to supply air and powder P. For example, the supply section 22 is configured to be connected to the dust collector 2 via a second pipe 20b, and supply air and powder P to the dust collector 2 via the second pipe 20b.

[0062] The air nozzle 23 includes an opening 24 configured to spray a drive flow toward the supply unit 22. The drive flow creates a negative pressure in the suction unit 21. For example, the air nozzle 23 includes a compressed air inlet 23a. The compressed air inlet 23a communicates with the opening 24 of the air nozzle 23. The air source 11 is connected to the compressed air inlet 23a via a piping 19. Compressed air is supplied to the opening 24 of the air nozzle 23, and the drive flow is sprayed from the opening 24. A solenoid valve 15A is provided in the piping 19. The solenoid valve 15A is controlled to open and close by a control unit 16. This changes the amount and timing of compressed air supply. The control unit 16 can also control the amount of compressed air supplied to the inlet 23a of the air nozzle 23 to be greater than the amount of compressed air supplied to the inlet 10a of the hopper 10. In this case, the suction unit 21 more easily generates a negative pressure.

[0063] According to the powder supply device 1A, a drive flow is ejected from the ejector 20 in the supply pipe 14A. The drive flow supplies the portion of powder P retained between the ejector 20 and the dust collector 2 in the supply pipe 14A from the supply pipe 14A to the dust collector 2. Therefore, according to the powder supply device 1A, the amount of powder P retained in the supply pipe 14A is reduced. As a result, the powder supply device 1A can stabilize the quantitative supply of powder P.

[0064] exist Figure 7In the example shown, the suction section 21, air nozzle 23, and supply section 22 divide a flow path F extending in one direction AX. The air nozzle 23 is positioned between the suction section 21 and the supply section 22. The suction section 21, air nozzle 23, and supply section 22 are arranged sequentially in one direction AX. An opening 24 includes a slit S extending circumferentially around the flow path F along the inner surface 23d of the air nozzle 23 that divides a portion of the flow path F. Compressed air supplied from the inlet 23a is supplied to the slit S via a groove 23b extending circumferentially around the flow path F. The inner surface 21a of the suction section 21 that divides a portion of the flow path F includes a conical surface that widens towards the opening end of the suction powder P. The inner surface 22a of the supply section 22 that divides a portion of the flow path F includes a conical surface that widens towards the opening end of the supply powder P. Furthermore, the structure of the ejector is not limited to... Figure 7 The example shown. The suction unit 21 can also be configured between the air nozzle 23 and the supply unit 22. In this case, powder P and air can be suctioned in a direction that intersects the direction in which the drive flow flows from the air nozzle 23 toward the supply unit 22.

[0065] The slit S is formed by a first conical surface 24a and a second conical surface 24b. The first conical surface 24a and the second conical surface 24b are inclined in the direction in which the compressed air supplied via the slot 23b forms a drive flow that is injected toward the supply section 22. The first conical surface 24a is adjacent to the supply section 22. The second conical surface 24b is opposite to the first conical surface 24a in a direction AX. In the ejector 20, the powder P in the flow path F flows along a direction AX, thus the ejector 20 can stabilize the metered supply of the powder P. According to the slit S, the drive flow is ejected from around the flow path F, thus stabilizing the drive flow.

[0066] The control unit 16 can also be configured to prevent the injection of the drive flow using the air nozzle 23 during the period when the force sensor 17 measures the weight of the hopper 10. Figure 8 This is a time graph showing the relationship between the control time of solenoid valves 15 and 15A in the powder supply device 1A, the measured weight of the force sensor 17, and the sampled weight. Figure 8 In the example shown, injection using the drive flow of air nozzle 23 is performed according to the injection cycle T4. The injection cycle T4 is the period following the calculation time T3. The control unit 16 can also be configured to perform injection using the drive flow of air nozzle 23 after the force sensor 17 measures the weight of hopper 10. The control unit 16, through methods such as... Figure 8 Controlling the injection of the drive flow as shown can reduce the noise generated by the air nozzle 23 while properly capturing the weight change of powder P.

[0067] Refer again Figure 6The structure of the powder supply device 1A will be described. The hopper 10 may also have a supply port 10c and a cover 10d. The supply port 10c communicates with the interior of the hopper 10. The cover 10d is configured to open and close the supply port 10c. For example, an operator opens the cover 10d to fill the hopper 10 with powder P via the supply port 10c. The control unit 16 may also be configured to control the ejection of a drive flow from the opening 24 of the air nozzle 23 when the supply port 10c is not closed by the cover 10d. For example, the hopper 10 may also have an opening / closing sensor for detecting the opening and closing of the cover 10d. For example, the opening and closing of the solenoid valve 15A may be linked to the opening and closing of the cover 10d.

[0068] If a driving flow is ejected from the opening 24 of the air nozzle 23, a negative pressure is generated in the suction section 21, thus drawing powder P and air from the outlet 10b. Therefore, when the cover 10d is opened to fill the hopper 10 with powder P, powder P and air are drawn from the outlet 10b, thus the powder supply device 1A can suppress the scattering of powder P in the hopper 10.

[0069] The following is for reference Figure 9 A powder supply device according to another embodiment will be described. Figure 9 The powder supply device 1B shown has, in addition to, the following features Figure 6 In addition to the structure of the powder supply device 1A shown, it also includes a pressure regulator 30. Hereinafter, the powder supply device 1B will be described focusing on the differences from the powder supply device 1A, and repeated descriptions will be omitted.

[0070] like Figure 9 As shown, the piping extending from the air source 11 branches into two piping sections at the branch point 12A. One piping is piping 12, which supplies air to the hopper 10, and the other piping is piping 19, which supplies air to the injector 20.

[0071] Pressure regulator 30 is provided on pipe 12. As a more specific example, pressure regulator 30 is provided between solenoid valve 15 and branch 12A on pipe 12. Pressure regulator 30 is connected to control unit 16 and configured to adjust the pressure supplied to nozzle 13 (see reference 12A) based on control signals from control unit 16. Figure 1 The pressure of compressed air.

[0072] As described in the above embodiments, when it is desired to control the injection time to supply a small amount of powder P, even if the injection time is shortened sufficiently, the amount of powder P supplied will be too large, and sometimes the target supply speed cannot be achieved.

[0073] Therefore, in addition to controlling the injection time, the control unit 16 also controls the pressure (injection pressure) of the air injected from the nozzle 13. For example, in Figure 4In the flowchart, when the supply speed calculated in step S16 is greater than the target supply speed (step S18: Yes), the control unit 16 reduces the injection time (step S20). In addition, for example, when the injection time reaches a predetermined lower limit, the control unit 16 also controls the pressure regulator 30 to reduce the pressure of the compressed air supplied to the nozzle 13.

[0074] If the pressure of the supplied air decreases, the reaction force of the jet from nozzle 13 decreases, and the movement of nozzle 13 within hopper 10 becomes slower. Consequently, the amount of powder P that is agitated and dispersed within hopper 10 decreases, further reducing the amount of powder P supplied from supply pipe 14A. Thus, according to the powder supply device 1B, the control unit 16 uses both jet time and jet pressure as control parameters, thereby enabling more precise control of the powder P supply amount and achieving more stable quantitative supply.

[0075] [Summary of embodiments of this disclosure]

[0076] This disclosure includes the following methods.

[0077] (Item 1) A powder supply device comprising: a storage section for storing powder; a supply pipe connected to the storage section; a nozzle disposed within the storage section, having flexibility, for injecting air into the storage section to supply air and the powder from the supply pipe; a measuring section for measuring the weight of the storage section; and a control section for controlling the injection time of the air injected by the nozzle based on the weight measured by the measuring section.

[0078] In this powder supply device, powder in the storage compartment is atomized by a flexible nozzle disposed within the storage compartment and introduced to the outside along with air through a supply pipe. The weight of the storage compartment is measured by a measuring unit. The injection time of the air ejected from the nozzle is controlled based on the measured weight. This powder supply device can control the air injection time according to the weight of the storage compartment, thus enabling the supply of a fixed amount of powder.

[0079] (Item 2) Based on the powder supply device described in Item 1, the control unit may stop the air jetting using the nozzle while the measuring unit is measuring the weight of the accumulated portion. In this case, the influence of the air jetting using the nozzle on the weight measurement of the accumulated portion can be avoided, and the powder supply device can properly measure the weight of the accumulated portion.

[0080] (Item 3) Based on the powder supply device described in Item 1 or 2, the control unit may, after repeatedly injecting air through the nozzle, have the measuring unit measure the weight of the accumulated portion. In this case, even if the weight change of the accumulated portion caused by a single injection is below the detection limit of the measuring unit, the powder supply device can appropriately measure the weight of the accumulated portion.

[0081] (Item 4) Based on the powder supply device described in any of Items 1 to 3, the control unit may calculate the powder supply speed based on the weight measured by the measuring unit and control the injection time of the air ejected from the nozzle so that the calculated supply speed is close to a preset target supply speed. In this case, the powder supply device can adjust the injection time to make the powder supply speed the target supply speed.

[0082] (Item 5) Based on the powder supply device described in Item 4, the control unit may further control the injection pressure of the air ejected from the nozzle to make the calculated supply speed close to the target supply speed. In this case, the powder supply device can adjust the injection pressure to make the powder supply speed the target supply speed.

[0083] (Item 6) Based on the powder supply device described in any of Items 1 to 5, the supply pipe may also have an injector, which includes: a suction section connected to the storage section; a supply section configured to supply the air and the powder; and an air nozzle including an opening configured to spray a drive flow toward the supply section, causing a negative pressure in the suction section. In this case, the powder retained in the supply pipe is supplied by the drive flow of the injector. Therefore, the amount of powder retained in the supply pipe is reduced, and the powder supply device can stabilize the quantitative supply of powder.

[0084] (Item 7) Based on the powder supply device described in Item 6, the aforementioned storage section may also include: a supply port communicating with the interior of the storage section; and a cover configured to open and close the supply port, wherein the control unit is configured to control the injection of the drive flow from the opening of the air nozzle when the supply port is not closed by the cover. In this case, when the cover is opened to fill the storage section with powder, powder and air are drawn from the storage section to the suction unit, thus the powder supply device can suppress the scattering of powder within the storage section.

Claims

1. A powder supply device, characterized in that, have: Storage section, storing powder; A supply pipe is connected to the storage section; A nozzle, disposed within the storage compartment, is flexible and injects air into the storage compartment, thereby supplying the air and the powder from the supply pipe. The measuring unit measures the weight of the storage unit; as well as The control unit controls the injection time of the air ejected from the nozzle based on the weight measured by the measuring unit.

2. The powder supply device according to claim 1, characterized in that, While the measuring unit is measuring the weight of the storage unit, the control unit stops the air jetting using the nozzle.

3. The powder supply device according to claim 1 or 2, characterized in that, After the control unit causes the nozzle to perform the air injection process multiple times, the measuring unit measures the weight of the storage unit.

4. The powder supply device according to claim 1 or 2, characterized in that, The control unit calculates the powder supply rate based on the weight measured by the measuring unit, and controls the injection time of the air ejected by the nozzle so that the calculated supply rate is close to the preset target supply rate.

5. The powder supply device according to claim 4, characterized in that, The control unit also controls the injection pressure of the air ejected by the nozzle so that the calculated supply speed is close to the target supply speed.

6. The powder supply device according to claim 1, characterized in that, The supply pipe has an ejector. The injector includes: The suction section is connected to the storage section; The supply unit is configured to supply the air and the powder; and An air nozzle includes an opening configured to spray a drive flow toward the supply section to generate negative pressure in the suction section.

7. The powder supply device according to claim 6, characterized in that, The storage section has: The supply port is connected to the storage section; and The cover is configured to open and close the supply port. The control unit is configured to control the injection of the drive flow from the opening of the air nozzle when the supply port is not closed by the cover.

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