Classification apparatus and shot processing apparatus

Abstract

To provide a classification device and a shot processing device capable of improving classification accuracy. [Solution] The classification device 40 includes a sorting mechanism 41 that sorts a group of powders and granules using airflow, a dust collector 44 that generates airflow, a conduit 42 that connects the sorting mechanism 41 and the dust collector 44 so that airflow can pass through it, a measuring instrument 45 that measures the pressure of the air containing the powders and granules upstream of the dust collector 44 in the airflow path, and a control device 46 that controls the airflow velocity based on the measured value measured by the measuring instrument 45.

Description

Technical Field

[0001] The present disclosure relates to a classification device and a shot processing device.

Background Art

[0002] There is known a classification device that separates powder and granular materials using an air flow. For example, Patent Document 1 describes a blasting device that generates an air flow in a classifier by operating a dust collector and recovers reusable projectiles by wind selection using the air flow.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the blasting device described in Patent Document 1, pressure detection means is provided in the secondary side flow path of the dust collection filter of the dust collector, and the rotational speed of the fan of the dust collector is controlled so that the air flow rate grasped based on the differential pressure detected by the pressure detection means approaches the target air flow rate. However, air flow may flow into the dust collector from other than the classifier. Therefore, even if the air flow rate is controlled using the differential pressure in the secondary side flow path of the dust collection filter of the dust collector, the wind speed in the classifier cannot be accurately controlled, and there is a risk that the classification accuracy will decrease.

[0005] The present disclosure describes a classification device and a shot processing device capable of improving classification accuracy.

Means for Solving the Problems

[0006] A classification apparatus relating to one aspect of this disclosure comprises a sorting mechanism, a dust collector, a conduit, a measuring instrument, and a control device. The sorting mechanism sorts a group of powders and granules using airflow. The dust collector generates airflow. The conduit connects the sorting mechanism and the dust collector, allowing airflow to pass through. The measuring instrument measures the pressure of the air containing the powders and granules upstream of the dust collector in the airflow path. The control device performs wind speed control, controlling the speed of the airflow based on the measured value obtained by the measuring instrument. [Effects of the Invention]

[0007] According to each aspect and embodiment of this disclosure, classification accuracy can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing a shot processing apparatus including a classification device according to one embodiment. [Figure 2] Figure 2 is a magnified perspective view showing the area around the measuring instrument shown in Figure 1. [Figure 3] Figure 3 is a schematic diagram illustrating an example of the sorting mechanism shown in Figure 1. [Figure 4] Figure 4 is a flowchart showing an example of a wind speed control method implemented by the control device shown in Figure 1. [Figure 5] Figure 5 is a diagram illustrating the wind speed control method shown in Figure 4. [Figure 6] Figure 6 shows the test results of the shot processing apparatus of the embodiment. [Figure 7] Figure 7 is a schematic diagram illustrating another example of the sorting mechanism shown in Figure 1. [Figure 8] Figure 8 shows another example configuration for achieving wind speed control. [Figure 9] Figure 9 is a schematic diagram showing a shot processing apparatus including a classification device according to another embodiment. [Figure 10] Figure 10 is a magnified perspective view showing the area around the measuring instrument shown in Figure 9. [Figure 11]Figure 11 is a schematic diagram illustrating an example of the sorting mechanism shown in Figure 9. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described in detail below with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0010] A shot blasting apparatus including a classification device according to one embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic configuration diagram showing a shot blasting apparatus including a classification device according to one embodiment. Figure 2 is a perspective view showing an enlarged view of the area around the measuring instrument shown in Figure 1. The shot blasting apparatus 1 shown in Figure 1 is a device that performs shot blasting on a workpiece. Examples of shot blasting include shot blasting and shot peening. The shot blasting apparatus 1 performs, for example, the removal of casting sand (mainly silica sand and carbonized additives) adhering to a cast part after casting (sand removal), and polishing and cleaning the surface of the casting. The shot blasting apparatus 1 includes a cabinet 10, a projection device 20, a recovery device 30, and a classification device 40.

[0011] Cabinet 10 is a housing capable of accommodating a workpiece. Inside Cabinet 10, a processing chamber is formed for applying shot blasting to the workpiece.

[0012] The projection device 20 is a device that performs shot blasting by projecting a blasting material onto a workpiece. The projection method of the projection device 20 may be air-powered or impeller-type (centrifugal). Examples of air-powered methods include gravity-powered, suction-powered, direct-pressure-powered (pressurized), and blower-type. In this embodiment, the impeller-type method will be used for explanation. Examples of blasting materials include steel shot and steel grit. The type of blasting material can be appropriately selected depending on the shot blasting process. The projection device 20 is installed above the cabinet 10. The projection device 20 includes a blasting material tank 21, a gate 22, and an impeller 23.

[0013] The projectile tank 21 stores projectiles. The gate 22 is provided at the lower part of the projectile tank 21. The gate 22 is a member for adjusting the area of the opening in the path from the projectile tank 21 toward the impeller 23 and for adjusting the amount of projectiles from the projectile tank 21 toward the impeller 23. The gate 22 supplies a certain amount of projectiles to the impeller 23. The impeller 23 is configured to project projectiles using centrifugal force. The impeller 23 is rotated at high speed by a driving device (not shown) such as a motor. Due to the centrifugal force generated with this rotation, the projectiles supplied onto the blades (not shown) of the impeller 23 are projected.

[0014] The recovery device 30 is a device for recovering the powder and granule group generated by the shot treatment. The powder and granule group includes the projectiles used in the shot treatment and the cutting powder of the processed object generated by the shot treatment. The recovery device 30 supplies the recovered powder and granule group to the classification device 40. The recovery device 30 includes a screw conveyor 31, a rotary screen 32, and a bucket elevator 33.

[0015] The screw conveyor 31 is a device for conveying the powder and granule group generated by the shot treatment. The screw conveyor 31 is provided below the cabinet 10 and extends horizontally. The screw conveyor 31 receives the powder and granule group generated by the shot treatment from the cabinet 10 and conveys it toward the bucket elevator 33. The screw conveyor 31 includes a shaft and blades provided in a spiral shape on the outer peripheral surface of the shaft. When the shaft rotates, the powder and granule group is conveyed by the blades.

[0016] The rotary screen 32 is a rotating sieve. The rotary screen 32 is provided at one end of the shaft of the screw conveyor 31 and removes foreign objects larger than the projectiles from the powder and granule group conveyed by the screw conveyor 31. The rotary screen 32 includes a cylindrical mesh body. The mesh of the mesh body has a diameter larger than the diameter of the projectiles.

[0017] The bucket elevator 33 conveys the group of granular materials from which foreign matters have been removed above the cabinet 10. The bucket elevator 33 is arranged parallel to the cabinet 10 and circulates a plurality of buckets. Each bucket scoops up the group of granular materials that have passed through the rotary screen 32 and conveys them above the cabinet 10, and supplies them to the classification device 40 through the discharge port 33a (supply port).

[0018] The classification device 40 is a device that selects reusable projection materials from the group of granular materials supplied from the recovery device 30. The classification device 40 is provided above the projection device 20 and supplies reusable projection materials to the projection device 20. The classification device 40 includes a selection mechanism 41, a conduit 42, a conduit 43, a dust collector 44, a measuring instrument 45, and a control device 46.

[0019] The selection mechanism 41 is a mechanism that selects a group of granular materials using an air flow F (see FIG. 3). Specifically, the selection mechanism 41 separates the group of granular materials into reusable projection materials and dust, which are other granular materials (a general term for cutting powder of the processing object generated by shot processing and projection materials that have become non-reusable sizes). The detailed configuration of the selection mechanism 41 will be described later. The selection mechanism 41 has an inlet 41a and an outlet 41b. The inlet 41a is an opening for introducing outside air into the selection mechanism 41. The outlet 41b is an opening for discharging the air flow containing dust from the selection mechanism 41.

[0020] The conduit 42 is provided between the selection mechanism 41 and the dust collector 44 and connects the selection mechanism 41 and the dust collector 44 so that the air flow can pass through. One end of the conduit 42 is connected to the outlet 41b of the selection mechanism 41, and the other end of the conduit 42 is connected to the dust collector 44. The conduit 43 connects the cabinet 10 and the dust collector 44. One end of the conduit 43 is connected to the side wall of the cabinet 10, and the other end of the conduit 43 joins the conduit 42 and is connected to the dust collector 44.

[0021] The dust collector 44 is a device for collecting dust. The dust collector 44 generates an airflow F that flows from the inlet 41a of the sorting mechanism 41, through the internal space of the sorting mechanism 41, and then through the conduit 42 towards the dust collector 44 by sucking air through the conduit 42. The dust collector 44 includes a housing 51, a filter 52, and a fan motor 53. The housing 51 houses the filter 52, a fan (not shown), the fan motor 53, and an inverter (not shown) that drives the fan motor 53. For the sake of explanation, in Figure 1, the fan motor 53 is shown on the outside of the housing 51.

[0022] The housing 51 has an intake port 51a and an exhaust port 51b. The other end of the conduit 42 is connected to the intake port 51a. The exhaust port 51b is an opening for exhausting clean air to the outside of the classification device 40 (housing 51). The filter 52 is a component for capturing dust sucked in by the dust collector 44. The fan motor 53 generates suction force by rotating the fan. The flow rate (velocity) of the airflow F can change depending on the rotation speed of the fan motor 53. In other words, the fan motor 53 is configured to allow adjustment of the flow rate (velocity) of the airflow F.

[0023] When the dust collector 44 is activated, heavier granular materials (reusable abrasive material) fall downwards within the sorting mechanism 41. Meanwhile, lighter granular materials (dust) are collected in the dust collector 44 via the conduit 42. Furthermore, dust generated in the cabinet 10 is collected in the dust collector 44 via the conduit 43. The dust sucked in by the dust collector 44 is captured using the filter 52. The clean air obtained by removing dust from the dust-containing airflow is discharged to the outside of the housing 51 through the exhaust port 51b.

[0024] The measuring instrument 45 is a device that measures the pressure (static pressure) of air containing powder and granular material upstream of the airflow F path from the dust collector 44. The measuring instrument 45 is, for example, a differential pressure gauge that measures the differential pressure (gauge pressure) relative to atmospheric pressure. In this embodiment, the measuring instrument 45 is installed in the conduit 42. Specifically, the measuring instrument 45 is installed in the conduit 42 at a position closer to the sorting mechanism 41 than to the dust collector 44. More specifically, the measuring instrument 45 is installed in the vicinity of the discharge port 41b of the conduit 42. The measuring instrument 45 measures the pressure of air containing powder and granular material inside the conduit 42. In other words, the measuring instrument 45 measures the differential pressure between the pressure inside the conduit 42 and atmospheric pressure. The differential pressure between the pressure inside the conduit 42 and atmospheric pressure is correlated with the wind speed of the airflow F inside the sorting mechanism 41. The measuring instrument 45 transmits the measured value to the control device 46.

[0025] As shown in Figure 2, the measuring instrument 45 includes a sensor body 81, a pipe 82, a fixing plate 83, and a mounting member 84. The sensor body 81 is located outside the airflow path of the airflow F. The sensor body 81 has ports 81a and 81b. The sensor body 81 measures the pressure in the space communicating with port 81a, using the pressure in the space communicating with port 81b as a reference. In this embodiment, the pipe 82 is connected to port 81a, and port 81b is open to the atmosphere.

[0026] The pipe 82 connects the airflow F to the sensor body 81. The pipe 82 has a cylindrical mounting member 84 inserted through it, with both ends open. One end of the pipe 82 is connected to the port 81a, and the other end of the pipe 82 is located inside the conduit 42. In other words, the sensor body 81 measures the differential pressure between the pressure inside the conduit 42 and atmospheric pressure. The pipe 82 is made of a flexible, soft material. Examples of such materials include polyvinyl chloride, polyurethane, and nylon. An opening 82a is provided at the other end of the pipe 82. The opening 82a faces in a direction intersecting the airflow F. In this embodiment, the pipe 82 extends in a direction perpendicular to the airflow F and opens in a direction perpendicular to the airflow F.

[0027] The outer surface of the mounting member 84 is provided with screw grooves, and the mounting member 84 is screwed into a mounting opening (socket) provided in the conduit 42. The fixing plate 83 is a member for fixing the sensor body 81. The fixing plate 83 has an L-shaped plate form and connects the sensor body 81 and the mounting member 84.

[0028] The control device 46 is a device (controller) that controls the wind speed (wind speed) of the airflow based on the measured value measured by the measuring instrument 45. The control device 46 is configured as a computer including, for example, a processor such as a CPU (Central Processing Unit), memory such as RAM (Random Access Memory) and ROM (Read Only Memory), and a communication device such as a network card. The control device 46 may be configured as a PLC (Programmable Logic Controller), or as a logic circuit using relay circuits and regulators. The control device 46 controls the wind speed so that the measured value measured by the measuring instrument 45 is maintained within the control range R (see Figure 5). In this embodiment, the control device 46 controls the wind speed by changing the rotation speed of the fan motor 53. The wind speed control method will be described later.

[0029] Next, an example of the sorting mechanism 41 will be described with reference to Figure 3. Figure 3 is a schematic diagram showing an example of the sorting mechanism shown in Figure 1. The sorting mechanism 41 shown in Figure 3 is a vertically opposed air flow type separator and includes a supply unit 61, a sorting unit 62, connecting piping 63, and a chamber 64.

[0030] The supply section 61 is the part that defines the supply path for supplying the powder and granular material group supplied from the bucket elevator 33 to the sorting section 62. The supply section 61 includes a grate 61a, a gate 61b, a swing plate 61c, and a dispersed steel plate 61d. The grate 61a is a mesh-like plate material provided below the outlet 33a of the bucket elevator 33 for removing foreign matter from the powder and granular material group. The size of the mesh (through holes) of the grate 61a is large enough for the projectile material to pass through. The gate 61b is a component for adjusting the flow rate of the powder and granular material group. The gate 61b is provided below the grate 61a and is inclined to narrow the supply path of the powder and granular material group as it goes downwards.

[0031] The swaying plate 61c is a component for homogenizing the flow of the powder and granular material. The swaying plate 61c is located downstream of the gate 61b in the supply path. When no powder and granular material is being supplied, the swaying plate 61c narrows the supply path of the powder and granular material, and when a powder and granular material is being supplied, it widens the supply path of the powder and granular material. The dispersed steel plate 61d reduces the falling velocity of the powder and granular material by damming it after it has passed through the grate 61a, gate 61b, and swaying plate 61c in order, and then supplies the powder and granular material to the sorting section 62.

[0032] The sorting section 62 is a part that sorts the powder and granular material group by mass difference using an airflow F. The sorting section 62 includes a container 62a, a piping section 62b, and a dispersion rod 62c. The container 62a is located above the abrasive material tank 21 and is a cylindrical member with open upper and lower ends. The container 62a has a tapered shape that decreases in diameter towards the bottom. The container 62a communicates with an inlet 41a located below the container 62a. The piping section 62b is a tubular member that extends in the vertical direction. The lower end of the piping section 62b is connected to the upper end of the container 62a. The dispersion rod 62c is located inside the piping section 62b and is a member that reduces the falling speed of the powder and granular material group.

[0033] The connecting pipe 63 connects the sorting section 62 and the chamber 64. One end of the connecting pipe 63 is located above the upper end of the pipe section 62b, and the other end of the connecting pipe 63 extends from the upper wall of the chamber 64 into the chamber 64. In the chamber 64, the powder and granular material contained in the airflow F that flows in through the connecting pipe 63 is further sorted. An outlet 64a is provided at the bottom of the chamber 64. An outlet 41b is provided at the top of the chamber 64.

[0034] When the dust collector 44 is in operation, outside air is drawn in through the inlet 41a, and inside the sorting mechanism 41, an airflow F is generated that flows from the inlet 41a through the container 62a, the piping section 62b, the connecting pipe 63, and the chamber 64 in sequence, and out through the outlet 41b to the conduit 42. In this state, when the group of powders and granules supplied from the supply section 61 falls from the upper end of the piping section 62b, an upward force acts on the group of powders and granules due to the airflow F. At this time, heavier powders and granules (for example, reusable abrasive material) fall downward against the airflow F and are supplied to the abrasive material tank 21 through the container 62a.

[0035] On the other hand, lighter granular materials rise with the airflow F and are transported through the connecting pipe 63 to the chamber 64. At the inlet of the chamber 64, the airflow F is descending, and furthermore, the airflow velocity decreases inside the chamber 64, which is wider than the connecting pipe 63. As a result, among the group of granular materials transported to the chamber 64, relatively heavier granular materials (for example, sand) separate from the airflow F and are discharged from the outlet 64a. The remaining lighter dust is then collected with the airflow F through the outlet 41b and the conduit 42 to the dust collector 44.

[0036] Next, a series of processes of the shot blasting method performed by the shot blasting apparatus 1 will be described. First, the workpiece is brought into the cabinet 10 and placed in a predetermined position. Then, the dust collector 44 is activated to generate an airflow F. Then, a fixed amount of abrasive material is supplied from the abrasive material tank 21 to the impeller 23 via the gate 22, and the impeller 23 uses centrifugal force to project the abrasive material towards the workpiece. In this way, the workpiece is shot blasted.

[0037] The granular material generated by the shot blasting process is supplied to the sorting mechanism 41 via a screw conveyor 31, a rotary screen 32, and a bucket elevator 33. In the sorting mechanism 41, the granular material is separated into reusable abrasive material and dust. The reusable abrasive material is supplied to the abrasive material tank 21, and the dust is collected in the dust collector 44 via a conduit 42. When the processing of the workpiece is complete, the shot blasting processing device 1 is stopped, and the workpiece is removed from the cabinet 10. Then, the next workpiece is brought into the cabinet 10.

[0038] Next, an example of a wind speed control method performed by the control device 46 will be described with reference to Figures 4 and 5. Figure 4 is a flowchart showing an example of a wind speed control method performed by the control device shown in Figure 1. Figure 5 is a diagram illustrating the wind speed control method shown in Figure 4. The series of processes of the wind speed control method shown in Figure 4 are started, for example, when the dust collector 44 starts operating. The measuring instrument 45 periodically transmits measured values ​​to the control device 46.

[0039] As shown in Figure 4, first, when the control device 46 receives a measured value from the measuring instrument 45, it determines whether the measured value is within the control range R (step S1). As shown in Figure 5, the control range R is the range of measured values ​​(here, the measured value of the differential pressure between the pressure inside the conduit 42 and atmospheric pressure) that can obtain an airflow F capable of properly performing sorting in the sorting mechanism 41. The control range R is the range between the upper limit Vu and the lower limit Vl. In this embodiment, the control range R includes the target value Vt. The upper limit Vu is the value obtained by adding a predetermined value to the target value Vt, and the lower limit Vl is the value obtained by subtracting the predetermined value from the target value Vt. In other words, in this embodiment, the difference between the upper limit Vu and the target value Vt is the same as the difference between the target value Vt and the lower limit Vl. The difference between the upper limit Vu and the target value Vt may be different from the difference between the target value Vt and the lower limit Vl.

[0040] The upper limit Vu and lower limit Vl may be calculated based on inference rules. These inference rules may be based on algorithms such as neural networks, Bayesian networks, and support vector machines, or they may be derived from case-based inference. The control range R may be updated each time by monitoring information about the operating environment and taking this information into account when determining the upper limit Vu and lower limit Vl.

[0041] The control device 46 determines, for example, that the measured value is within the control range R if it is less than or equal to the upper limit Vu of the control range R and greater than or equal to the lower limit Vl of the control range R. The control device 46 determines, for example, that the measured value is outside the control range R if it is greater than the upper limit Vu or less than the lower limit Vl. In step S1, if the control device 46 determines that the measured value is within the control range R (step S1: YES), it repeats step S1 using the next measured value.

[0042] On the other hand, in step S1, if the control device 46 determines that the measured value is outside the control range R (step S1: NO), it determines whether that state (abnormal state) continues for the detection time Td (step S2). For example, if all measured values ​​measured by the measuring instrument 45 remain above the upper limit Vu from the time it is determined in step S1 that the measured value is greater than the upper limit Vu until the detection time Td has elapsed, the control device 46 determines that the abnormal state has continued for the detection time Td. If any one of the measured values ​​measured by the measuring instrument 45 becomes less than or equal to the upper limit Vu from the time it is determined in step S1 that the measured value is greater than the upper limit Vu until the detection time Td has elapsed, the control device 46 determines that the abnormal state did not continue for the detection time Td.

[0043] Similarly, if, after it is determined in step S1 that the measured value is smaller than the lower limit Vl, all measured values ​​taken by the measuring instrument 45 remain smaller than the lower limit Vl until the detection time Td has elapsed, the control device 46 determines that the abnormal condition has persisted for the duration of the detection time Td. If, after it is determined in step S1 that the measured value is smaller than the lower limit Vl, any one of the measured values ​​taken by the measuring instrument 45 becomes greater than or equal to the lower limit Vl until the detection time Td has elapsed, the control device 46 determines that the abnormal condition did not persist for the duration of the detection time Td. In step S2, if the control device 46 determines that the abnormal condition did not persist for the duration of the detection time Td (step S2: NO), it repeats step S1 using the next measured value.

[0044] On the other hand, in step S2, if the control device 46 determines that the abnormal condition continues for the detection time Td (step S2: YES), it performs wind speed control (step S3). In step S3, the control device 46 performs wind speed control so that the measured value is maintained within the control range R. Specifically, the control device 46 performs wind speed control by controlling the inverter that drives the fan motor 53 to change the rotational speed of the fan motor 53. For example, if the measured value is greater than the upper limit Vu, the control device 46 reduces the rotational speed of the fan motor 53 by decreasing the drive frequency of the inverter by a predetermined frequency. If the measured value is less than the lower limit Vl, the control device 46 increases the rotational speed of the fan motor 53 by increasing the drive frequency of the inverter by a predetermined frequency. The amount of increase and decrease in the drive frequency may be the same or different.

[0045] Next, the control device 46 determines whether or not a waiting time Tw has elapsed since the completion of wind speed control in step S3 (step S4). If the control device 46 determines that the waiting time Tw has not elapsed (step S4: NO), it repeats the determination in step S4 until the waiting time Tw has elapsed. On the other hand, if the control device 46 determines that the waiting time Tw has elapsed (step S4: YES), it performs step S1 again using the next measured value. In other words, the control device 46 stops wind speed control from the completion of wind speed control until the waiting time Tw has elapsed. Steps S1 to S4 are then repeated. Note that the above wind speed control method may be performed continuously during shot processing (i.e., while the shot processing device 1 is in operation). Alternatively, the above wind speed control method may be performed at predetermined timings, in which case steps S1 to S4 do not need to be repeated. Examples of the above timings include the startup of the shot processing device 1 and predetermined timings while the shot processing device 1 is in operation.

[0046] The contents of this disclosure will be specifically explained below with reference to Figure 6 and using examples. This disclosure is not limited to the following examples. Figure 6 is a diagram showing the test results of a shot processing apparatus of an example. The horizontal axis of Figure 6 shows the time elapsed from the start of operation of the shot processing apparatus. The vertical axis on the left of Figure 6 shows pressure (unit: kPa). The vertical axis on the right of Figure 6 shows the drive frequency (unit: Hz). Figure 6 shows the change over time of the drive frequency fd of the inverter that drives the fan motor, the differential pressure Pd of the dust collector filter, and the pressure Pc in the conduit connecting the sorting mechanism and the dust collector.

[0047] In this embodiment, the shot processing device 1 (shot blasting machine) shown in Figure 1 was used. A single 15kW impeller 23 was used as the impeller 23, and a vertically opposed airflow type separator shown in Figure 3 was used as the sorting mechanism 41. In this embodiment, the wind speed control method shown in Figure 4 was used, with the target value Vt set to 0.6kPa and the control range R set to 0.3kPa to 0.9kPa.

[0048] As shown in Figure 6, in this embodiment, the drive frequency fd fluctuates due to the wind speed control method. As a result, the differential pressure Pd increases as time passes from the start of operation of the shot blasting machine, but the pressure Pc remains stable within a nearly constant range. This indicates that the classification capacity of the classifier is stable.

[0049] In the classification apparatus 40 described above, the group of powders and granules is sorted using the airflow F generated by the dust collector 44, and the airflow velocity is controlled based on the measured value of the pressure of the air containing the powders and granules, measured by the measuring instrument 45 upstream of the airflow F flow path from the dust collector 44. Here, the measuring instrument 45 measures the differential pressure between the pressure in the conduit 42 and atmospheric pressure. Upstream of the airflow F flow path from the dust collector 44, the influence of airflows flowing in from sources other than the sorting mechanism 41 is smaller than that of the exhaust port 51b of the dust collector 44. Therefore, the pressure in the conduit 42 is correlated with the velocity of the airflow F in the sorting mechanism 41. Since the velocity of the airflow F in the sorting mechanism 41 affects the classification accuracy, the velocity of the airflow F in the sorting mechanism 41 can be controlled accurately by measuring the pressure in the conduit 42. As a result, it is possible to improve the classification accuracy.

[0050] Furthermore, the amount of granular material contained in the airflow F within the conduit 42 is less than the amount of granular material contained in the airflow F within the sorting mechanism 41. Therefore, the pressure within the conduit 42 is less affected by the granular material and remains stable, with little fluctuation between processing and non-processing of the workpiece. Consequently, by using the pressure within the conduit 42, the velocity of the airflow F within the sorting mechanism 41 can be controlled with greater precision. As a result, the classification accuracy can be further improved.

[0051] One possible configuration is to control the velocity of the airflow F inside the sorting mechanism 41 by installing an airflow velocity sensor inside the sorting mechanism 41 or near the discharge port 41b and directly measuring the velocity of the airflow F. However, since the airflow F inside the sorting mechanism 41 and near the discharge port 41b contains granular material, there is a risk that the airflow velocity sensor may malfunction due to collisions with the granular material. Therefore, it is difficult to measure the airflow velocity continuously. On the other hand, in the classifier 40, the sensor body 81 is located outside the flow path, and the flow path and the sensor body 81 are connected by a pipe 82. Therefore, the sensor body 81 does not collide with granular material, and thus, malfunction of the sensor body 81 due to granular material can be avoided. Therefore, the pressure inside the flow path (in this case, the pressure inside the conduit 42) can be measured continuously.

[0052] The airflow F passing through the conduit 42 may contain dust (granular material). If the opening 82a of the pipe 82 is positioned facing the airflow F, that is, facing the outlet 41b, then granular material may enter the pipe 82 and accumulate inside it. In this case, the sensor body 81 may not be able to accurately measure the pressure inside the conduit 42. In the classifier 40, the opening 82a of the pipe 82 is oriented in a direction intersecting the airflow F. Therefore, the possibility of granular material entering the pipe 82 is reduced. Consequently, the possibility of a decrease in the accuracy of pressure measurement inside the conduit 42 can be reduced.

[0053] The pipe 82 is made of a flexible material. Therefore, even if powder or granular material collides with the pipe 82, the possibility of the pipe 82 being damaged can be reduced.

[0054] In the classification device 40, the control device 46 controls the airflow velocity by changing the rotational speed of the fan motor 53. When the rotational speed of the fan motor 53 increases, the airflow velocity of the airflow F inside the sorting mechanism 41 increases, and when the rotational speed of the fan motor 53 decreases, the airflow velocity of the airflow F inside the sorting mechanism 41 decreases. Therefore, airflow velocity control can be achieved by changing the rotational speed of the fan motor 53.

[0055] Since the wind speed of the airflow F is prone to fluctuations, the measured value may temporarily fall outside the control range R. If wind speed control is performed in such a case, the wind speed control may be performed frequently, making it impossible to stably maintain the measured value within the control range R. In contrast, in the classifier 40, the control device 46 performs wind speed control in response to the state in which the measured value remains outside the control range R for a detection time Td. With this configuration, wind speed control is performed only when the measured value is continuously outside the control range R, so the situation in which wind speed control is performed frequently can be avoided, and the measured value can be stably maintained within the control range R. As a result, it becomes possible to further improve the classification accuracy.

[0056] After wind speed control is implemented, it takes some time for the wind speed of the airflow F to stabilize. Therefore, immediately after wind speed control is implemented, the measured value may still remain outside the control range R. In such cases, if wind speed control is performed, it may be performed frequently, making it impossible to stably maintain the measured value within the control range R. In contrast, in the classifier 40, the control device 46 stops wind speed control after the wind speed control is completed until a waiting time Tw has elapsed. With this configuration, wind speed control can be stopped after the wind speed control is completed until the wind speed of the airflow F stabilizes, thus avoiding the situation where wind speed control is performed frequently, and the measured value can be stably maintained within the control range R. As a result, it becomes possible to further improve the classification accuracy.

[0057] In the shot processing apparatus 1, shot blasting is performed by projecting abrasive material onto the workpiece. The resulting powder and granular material is supplied to the classifier 40, where reusable abrasive material is selected and supplied to the projection apparatus 20. In shot blasting, the efficiency of the shot blasting can be improved by using abrasive material with a particle size distribution suitable for processing. Repeated use of abrasive material can cause cracking, chipping, and wear. In the shot processing apparatus 1, the classifier 40, which can improve classification accuracy, can accurately remove abrasive material that does not contribute to shot blasting from the powder and granular material. Therefore, abrasive material with an appropriate particle size distribution can be continuously supplied to the projection apparatus 20. As a result, the efficiency of shot blasting can be improved. By using abrasive material with an appropriate particle size distribution, it becomes possible to process multiple workpieces with the same quality.

[0058] The classification apparatus and shot processing apparatus described herein are not limited to the embodiments described above.

[0059] For example, in sand removal, since attached sand is removed from the casting in the initial stages of the process, a large amount of attached sand is mixed into the granular material generated by shot blasting. From the middle stages of the process onward, the main focus is on polishing and cleaning the casting surface, so the amount of attached sand mixed into the granular material decreases, and surface cutting dust and shot fragments may be mixed into the granular material. If the same control range R is used in these processes, in the initial stages, the removal of attached sand may be insufficient, and the abrasive material may be reused, while in the middle stages and beyond, reusable abrasive material may be discarded. Therefore, the control range R may be set (changed) for each shot blasting process according to its purpose. The operator may set and change the control range R, or a pre-set control range R may be switched for each process. For example, when dust generation is low, the operating power of the dust collector 44 can be reduced, making it possible to reduce power consumption.

[0060] The measuring instrument 45 only needs to be able to measure the pressure in the airflow F upstream of the dust collector 44, and may be installed in the sorting mechanism 41. In this case, the sensor body 81 is placed outside the classifier 40 (for example, on the outer surface of the side wall of the sorting mechanism 41), and the pipe 82 connects the inside of the sorting mechanism 41 to the sensor body 81. The measuring instrument 45 measures the air pressure inside the sorting mechanism 41. In other words, the measuring instrument 45 measures the differential pressure between the pressure inside the sorting mechanism 41 and atmospheric pressure. For this reason, the measured value of the pressure inside the sorting mechanism 41 is used for wind speed control. Although the pressure inside the sorting mechanism 41 is affected by the powder and granules, the degree of influence is relatively small, and the pressure inside the sorting mechanism 41 (the differential pressure between the pressure inside the sorting mechanism 41 and atmospheric pressure) is correlated with the wind speed of the airflow F inside the sorting mechanism 41. Therefore, the velocity of the airflow F inside the sorting mechanism 41 can be controlled with high precision, making it possible to improve the classification accuracy.

[0061] The measuring instrument 45 may be installed at the outlet 33a that supplies the powder and granular material to the sorting mechanism 41. For example, the sensor body 81 is located outside the classifier 40 (for example, on the outer surface of the side wall of the sorting mechanism 41), and the pipe 82 connects the inside of the outlet 33a to the sensor body 81. The measuring instrument 45 measures the air pressure at the outlet 33a. In other words, the measuring instrument 45 measures the differential pressure between the air pressure at the outlet 33a and atmospheric pressure. For this reason, the measured value of the air pressure at the outlet 33a is used for wind speed control. Although the air pressure at the outlet 33a is affected by the powder and granular material, the air pressure at the outlet 33a (the differential pressure between the air pressure at the outlet 33a and atmospheric pressure) is correlated with the wind speed of the airflow F inside the sorting mechanism 41. Therefore, the speed of the airflow F inside the sorting mechanism 41 can be controlled with high precision, making it possible to improve the classification accuracy.

[0062] The measuring instrument 45 only needs to include the sensor body 81, and does not need to include the pipe 82, fixing plate 83, and mounting member 84. The measuring instrument 45 may measure absolute pressure instead of differential pressure.

[0063] In the above embodiment, the control device 46 is a control device dedicated to wind speed control, but the control device 46 may also control the shot processing device 1 in a comprehensive manner.

[0064] In the above embodiment, the control device 46 controls the wind speed so that the measured value from the measuring instrument 45 is maintained within the control range R. The control device 46 may also control the wind speed so that the measured value from the measuring instrument 45 approaches the target value Vt without using the control range R. The control device 46 may convert the measured value from the measuring instrument 45 into the velocity of the airflow F in the sorting mechanism 41 and use that velocity to control the wind speed. For example, the control device 46 may control the wind speed so that the converted velocity is maintained within the control range including the target velocity, or it may control the wind speed so that the converted velocity approaches the target velocity.

[0065] The control device 46 may perform stepwise airflow speed control over a predetermined operating time. In this case, the airflow speed of the airflow F within the sorting mechanism 41 changes gradually, which can suppress turbulence in the airflow F. As a result, the classification accuracy can be further improved.

[0066] In the above embodiment, the sorting mechanism 41 is a vertically opposed airflow type separator, but the sorting mechanism 41 may be a different type of separator. Another example of the sorting mechanism 41 will be described with reference to Figure 7. Figure 7 is a schematic diagram showing another example of the sorting mechanism shown in Figure 1. The sorting mechanism 41 shown in Figure 7 is a horizontal right-angle airflow type separator and includes a supply unit 71 and a chamber 72.

[0067] The supply section 71 defines the supply path for supplying the powder and granular material group supplied from the bucket elevator 33 to the chamber 72. Part of the supply section 71 is located inside the chamber 72. The supply section 71 includes a grate 71a, a gate 71b, a swing plate 71c, and a scattering prevention sheet 71d.

[0068] The grate 71a is a mesh-like plate located below the outlet 33a of the bucket elevator 33, used to remove foreign matter from the powder and granular material. The mesh size (through-holes) of the grate 71a is large enough for the projectile material to pass through. The gate 71b is a component for adjusting the flow rate of the powder and granular material. The gate 71b is located inside the chamber 72, below the grate 71a. The gate 71b is inclined to narrow the supply path of the powder and granular material as it goes downwards.

[0069] The oscillating plate 71c is a component for homogenizing the flow of the powder and granular material. The oscillating plate 71c is installed inside the chamber 72 and is located downstream of the gate 71b in the supply path. When no powder and granular material is being supplied, the oscillating plate 71c narrows the supply path of the powder and granular material, and when a powder and granular material is being supplied, it widens the supply path of the powder and granular material. The scattering prevention sheet 71d is installed inside the chamber 72 and hangs down from the upper wall of the chamber 72. The scattering prevention sheet 71d is a component for preventing the scattering of the powder and granular material after it has passed through the grate 71a, gate 71b, and oscillating plate 71c in order.

[0070] Chamber 72 has two side walls 72a and 72b at its upper part, facing each other horizontally. Between side walls 72a and 72b, a supply section 71 extends from the upper wall of chamber 72 toward the bottom of chamber 72. Side wall 72a is inclined to expand the internal space of chamber 72 as it goes downwards. An inlet 41a is provided in side wall 72a. An outlet 41b is provided in side wall 72b. At the bottom of chamber 72, outlets 72c, 72d, and 72e are provided in that order, from side wall 72a toward side wall 72b.

[0071] When the dust collector 44 is in operation, outside air is drawn in through the inlet 41a, and an airflow F is generated inside the chamber 72 from the inlet 41a towards the outlet 41b. The flow path of the airflow F is curved downwards to avoid the supply unit 71. In this state, when a group of powders and granules is supplied from the supply unit 71, the airflow F acts on the group of powders and granules in a nearly horizontal direction. At this time, heavier powders and granules (for example, reusable abrasive material) fall near the inlet 41a and are supplied to the abrasive material tank 21 through the outlet 72c. Lighter powders and granules are carried toward the outlet 41b by the airflow F.

[0072] As the airflow F passes below the supply unit 71, it rises towards the discharge port 41b. At this time, a portion of the granular material carried by the airflow F that is relatively heavy (a mixture of abrasive material and fine powder) separates from the airflow F and is discharged from the discharge port 72d, supplied to an overflow tank (not shown). The granular material supplied to the overflow tank is then supplied again to the sorting mechanism 41. Further, a portion of the remaining granular material that is relatively heavy (fine powder) separates from the airflow F and is discharged from the discharge port 72e. Meanwhile, the remaining lighter dust is collected by the dust collector 44 through the conduit 42 from the discharge port 41b along with the airflow F.

[0073] The sorting mechanism 41 may also be a cyclone-type sorting mechanism.

[0074] In the above embodiment, the control device 46 controls the wind speed by changing the rotational speed of the fan motor 53, but the method of realizing wind speed control is not limited to this. Another method of realizing wind speed control will be described with reference to Figure 8. Figure 8 is a diagram showing another example configuration for realizing wind speed control. In the example configuration shown in Figure 8, the classifier 40 further includes a damper 47 (flow regulator). The damper 47 is a device for adjusting the suction force of the dust collector 44. The damper 47 is provided in the flow path (conduit 42) between the sorting mechanism 41 and the dust collector 44. The damper 47 is configured so that its opening degree can be adjusted.

[0075] In the configuration example shown in Figure 8, the control device 46 controls the airflow velocity by changing the opening degree of the damper 47. The flow rate of the airflow from the sorting mechanism 41 to the dust collector 44 is adjusted by changing the opening degree of the damper 47. For example, when the opening degree of the damper 47 is increased, the flow rate of the airflow from the sorting mechanism 41 to the dust collector 44 increases, so the airflow velocity of the airflow F increases. When the opening degree of the damper 47 is decreased, the flow rate of the airflow from the sorting mechanism 41 to the dust collector 44 decreases, so the airflow velocity of the airflow F decreases. Therefore, airflow velocity control can be achieved by changing the opening degree of the damper 47.

[0076] The control device 46 may control the wind speed by changing both the rotational speed of the fan motor 53 and the opening degree of the damper 47. For example, the control device 46 may first change the rotational speed of the fan motor 53, and then change the opening degree of the damper 47 in accordance with the rotational speed of the fan motor 53 reaching an upper or lower limit.

[0077] Next, a shot processing apparatus including a classification device according to another embodiment will be described with reference to Figures 9 to 11. Figure 9 is a schematic configuration diagram showing a shot processing apparatus including a classification device according to another embodiment. Figure 10 is a perspective view showing an enlarged view of the area around the measuring instrument shown in Figure 9. Figure 11 is a schematic diagram showing an example of the sorting mechanism shown in Figure 9. The shot processing apparatus 1A shown in Figure 9 is a device that applies shot processing to a workpiece, similar to the shot processing apparatus 1. The shot processing apparatus 1A mainly differs from the shot processing apparatus 1 in that it includes a projection device 20A and a classification device 40A instead of the projection device 20, recovery device 30, and classification device 40.

[0078] The projection device 20A is a device that performs shot blasting by projecting abrasive material onto a workpiece inside the cabinet 10. In this embodiment, an air-powered projection device is exemplified as the projection device 20A. The projection device 20A mainly differs from the projection device 20 in that it includes a nozzle 24 instead of an impeller 23. The nozzle 24 is installed inside the cabinet 10 so that the nozzle's nozzle opening faces the workpiece. The nozzle 24 injects the abrasive material supplied from the abrasive material tank 21 together with compressed air C. The lower part of the cabinet 10 defines a recovery space that, for example, has a tapered shape that narrows in width towards the bottom. The abrasive material sprayed from the nozzle 24 toward the workpiece is recovered in the recovery space of the cabinet 10.

[0079] The classifier 40A differs from the classifier 40 mainly in that it includes a sorting mechanism 41A, a measuring instrument 45A, and a recovery pipe 48 instead of the sorting mechanism 41, conduit 43, and measuring instrument 45. The recovery pipe 48 is provided between the cabinet 10 and the sorting mechanism 41A and connects the cabinet 10 and the sorting mechanism 41A so that an airflow F can pass through. One end of the recovery pipe 48 is connected to the bottom of the cabinet 10, and the other end of the recovery pipe 48 is connected to the sorting mechanism 41A. The recovery pipe 48 provides an airtight connection between the cabinet 10 and the sorting mechanism 41A. The recovery pipe 48 carries the powder and granular material generated by the shot blasting process to the sorting mechanism 41A on the airflow F.

[0080] Measuring instrument 45A, like measuring instrument 45, measures the pressure (static pressure) of the air containing the powder and granular material upstream of the airflow F path from the dust collector 44. Measuring instrument 45A is, for example, a differential pressure gauge that measures the differential pressure (gauge pressure) relative to atmospheric pressure. In this embodiment, measuring instrument 45A is installed in the recovery pipe 48. Specifically, measuring instrument 45A is installed in the recovery pipe 48 closer to the sorting mechanism 41A than to the cabinet 10. More specifically, measuring instrument 45A is installed in the recovery pipe 48 near the inlet 41a of the sorting mechanism 41A. Measuring instrument 45A measures the pressure of the air containing the powder and granular material inside the recovery pipe 48. In other words, measuring instrument 45A measures the differential pressure between the pressure inside the recovery pipe 48 and atmospheric pressure. The differential pressure between the pressure inside the recovery pipe 48 and atmospheric pressure is correlated with the wind speed of the airflow F inside the sorting mechanism 41A. The measuring instrument 45A transmits the measured value to the control device 46.

[0081] As shown in Figure 10, the measuring instrument 45A differs from the measuring instrument 45 mainly in that it does not include the pipe 82, the fixing plate 83, and the mounting member 84. In this embodiment, a socket 48a is provided on the side of the piping section that constitutes the recovery pipe 48. The socket 48a is a tubular member that connects the inside of the recovery pipe 48 to the outside of the recovery pipe 48. The socket 48a does not protrude into the recovery pipe 48. Port 81a of the sensor body 81 is connected to the socket 48a, and port 81b (see Figure 2) is open to the atmosphere.

[0082] The sorting mechanism 41A, like the sorting mechanism 41, is a mechanism that sorts powder and granular material using an airflow F. In this embodiment, a cyclone-type sorting mechanism is exemplified as the sorting mechanism 41A.

[0083] As shown in Figure 11, the sorting mechanism 41A includes a cyclone body 65, an inlet 41a, and an outlet 41b. The cyclone body 65 includes a straight section 65a and a reduced-diameter section 65b. The straight section 65a has a hollow cylindrical shape with a substantially constant radius. The reduced-diameter section 65b is provided continuously downward from the straight section 65a. The reduced-diameter section 65b has a hollow conical shape that narrows in diameter as it extends downward. The central axis of the reduced-diameter section 65b is coaxial with the central axis AX of the straight section 65a. An outlet 65c is provided at the bottom of the reduced-diameter section 65b.

[0084] The inlet 41a is an opening that introduces the airflow F containing the powder and granular material into the cyclone body 65. The inlet 41a is located at the top of the cyclone body 65. Specifically, the inlet 41a is located on the side of the straight section 65a. The other end of the recovery pipe 48 is connected to the inlet 41a. The discharge port 41b is an opening that discharges the airflow F containing dust from the cyclone body 65. The discharge port 41b is located at the top of the cyclone body 65. One end of the conduit 42 is connected to the discharge port 41b. Due to the suction force of the dust collector 44, a downward airflow swirling around the central axis AX is generated inside the cyclone body 65, and in the reduced diameter section 65b, the downward airflow changes into an upward airflow.

[0085] In the shot processing device 1A, when the dust collector 44 is in operation, outside air is drawn in from an inlet (not shown) located at the top of the cabinet 10, and an airflow F is generated that travels from the cabinet 10 through the recovery pipe 48, the cyclone body 65, and the conduit 42 in order towards the dust collector 44. The airflow F transports the group of powders and granular materials, including the used abrasive material collected in the recovery space of the cabinet 10, through the recovery pipe 48 to the cyclone body 65.

[0086] Inside the cyclone body 65, the airflow F descends while swirling around the central axis AX. At this time, the heavier granular material (reusable abrasive material) is separated to the outside by centrifugal force, detached from the airflow F, and descends, being discharged from the outlet 65c into the abrasive material tank 21. Then, at the reduced diameter section 65b, the airflow F changes into an upward airflow, and the lighter granular material rises with the upward airflow (airflow F), is collected from the outlet 41b through the conduit 42 into the dust collector 44.

[0087] In the shot processing device 1A, the same effects as in the shot processing device 1 can be obtained with the same configuration as in the shot processing device 1. In the classifier 40A, the same effects as in the classifier 40 can be obtained with the same configuration as in the classifier 40. When a cyclone-type sorting mechanism is used as the sorting mechanism 41A, if the velocity of the airflow F inside the sorting mechanism 41A (cyclone body 65) fluctuates, the centrifugal force inside the cyclone body 65 fluctuates, which may reduce the sorting accuracy. Even when a cyclone-type sorting mechanism is used as the sorting mechanism 41A, upstream of the dust collector 44 in the airflow path of the airflow F, the influence of airflows flowing in from sources other than the sorting mechanism 41 is smaller than that of the exhaust port 51b of the dust collector 44. Therefore, the pressure upstream of the dust collector 44 in the airflow path of the airflow F is correlated with the velocity of the airflow F inside the sorting mechanism 41A. Consequently, by measuring this pressure, the velocity of the airflow F inside the sorting mechanism 41A can be controlled with high precision. As a result, it is possible to improve the sorting accuracy.

[0088] In the classification device 40A, the measuring instrument 45A measures the differential pressure between the pressure inside the recovery pipe 48 and atmospheric pressure. Since the recovery pipe 48 is connected to the inlet 41a, the pressure inside the recovery pipe 48 has a strong correlation with the velocity of the airflow F introduced into the cyclone body 65 from the inlet 41a (i.e., the airflow F inside the sorting mechanism 41A). Therefore, by measuring the pressure inside the recovery pipe 48, the velocity of the airflow F inside the sorting mechanism 41A can be controlled with greater precision. As a result, the classification accuracy can be further improved.

[0089] The airflow F passing through the recovery pipe 48, the sorting mechanism 41A, and the conduit 42 contains granular material. In the classifier 40A, the sensor body 81 is located outside the flow path, and the flow path and the sensor body 81 are connected by a socket 48a. Therefore, the sensor body 81 does not come into contact with the granular material, thus preventing damage to the sensor body 81 due to the granular material. Furthermore, since neither the measuring instrument 45A nor the socket 48a protrudes into the flow path, the possibility of turbulence in the airflow F is reduced. This improves the accuracy of pressure measurement.

[0090] The classification device 40 may include measuring instrument 45A instead of measuring instrument 45. The classification device 40A may include measuring instrument 45 instead of measuring instrument 45A.

[0091] The combination of the projection method of the projection device and the sorting method of the sorting mechanism can be changed as needed. For example, a combination of an impeller-type (centrifugal) projection device and a cyclone-type sorting mechanism as shown in Figure 11 may be used, or an air-type projection device and an air-selection type sorting mechanism as shown in Figure 3 or Figure 7 may be used.

[0092] This disclosure includes the forms described in the following clauses.

[0093] (Clause 1) A sorting mechanism that uses airflow to separate groups of powders and granules, A dust collector that generates the aforementioned airflow, A conduit connecting the sorting mechanism and the dust collector so that the airflow can pass through, A measuring instrument for measuring the pressure of air containing powder and granular material, located upstream of the dust collector in the airflow path, A control device that controls the wind speed based on the measured values ​​measured by the measuring instrument, A classification device equipped with the following features.

[0094] (Article 2) The classification apparatus according to Clause 1, wherein the measuring instrument includes a sensor body provided outside the flow path and a pipe connecting the flow path and the sensor body.

[0095] (Article 3) The classification apparatus according to Clause 2, wherein the pipe has an opening in a direction intersecting the airflow.

[0096] (Article 4) The classification apparatus according to Clause 2 or Clause 3, wherein the pipe is made of a flexible material.

[0097] (Article 5) The classification apparatus described in any one of Clauses 1 to 4, wherein the pressure of the air is a differential pressure with respect to atmospheric pressure.

[0098] (Article 6) The measuring instrument is a classification device according to any one of Clauses 1 to 5, which measures the pressure of the air in the conduit.

[0099] (Article 7) The measuring instrument is a classification device according to any one of Clauses 1 to 5, which measures the pressure of the air within the sorting mechanism.

[0100] (Clause 8) The classification apparatus according to any one of Clauses 1 to 5, wherein the measuring instrument measures the pressure of the air at the supply port for supplying the group of powders to the sorting mechanism.

[0101] (Article 9) The system further includes a recovery pipe that connects the cabinet containing the workpiece to be processed and the sorting mechanism so that the airflow can pass through it. The sorting mechanism is a cyclone-type sorting mechanism, as described in any one of Clauses 1 to 5.

[0102] (Clause 10) The measuring instrument is a classification device according to Clause 9, which measures the pressure of the air in the recovery pipe.

[0103] (Article 11) A classification apparatus as described in any one of Clauses 1 to 8, A projection device that performs shot blasting by projecting a projectile onto a workpiece, A recovery device for recovering the granular material generated by the shot processing and supplying the granular material to the classification device, Equipped with, The classification apparatus is a shot processing apparatus that selects reusable abrasive material from the group of powders and granules and supplies the abrasive material to the projection apparatus.

[0104] (Article 12) The classification apparatus described in Clause 9 or Clause 10, The aforementioned cabinet, A projection device that performs shot blasting by projecting a projectile onto the workpiece inside the cabinet, Equipped with, The recovery pipe carries the group of powder and granular material generated by the shot processing to the sorting mechanism via the airflow. The classification apparatus is a shot processing apparatus that selects reusable abrasive material from the group of powders and granules and supplies the abrasive material to the projection apparatus.

[0105] In the classification apparatus described in Clause 1, the group of powders and granules is sorted using the airflow generated by the dust collector, and the airflow velocity is controlled based on the measured pressure of the air containing the powders and granules, measured by a measuring instrument upstream of the dust collector in the airflow path. The air pressure upstream of the dust collector is correlated with the velocity of the airflow within the sorting mechanism. Therefore, the velocity of the airflow within the sorting mechanism can be controlled with high precision. As a result, the classification accuracy can be improved.

[0106] In the classification apparatus described in Clause 2, the sensor body is located outside the flow path, and the flow path and the sensor body are connected by a pipe, so that the sensor body does not come into contact with any powder or granular material. Therefore, the pressure inside the flow path can be measured continuously.

[0107] In the classification apparatus described in Clause 3, the possibility of powder or granular material entering the pipe is reduced. Therefore, the possibility of a decrease in the accuracy of pressure measurement in the flow path can be reduced.

[0108] In the classification apparatus described in Clause 4, even if the powder or granular material collides with the pipe, the possibility of the pipe being damaged can be reduced.

[0109] In the classification apparatus described in Clause 5, a differential pressure based on atmospheric pressure is used. In this case as well, the velocity of the airflow within the sorting mechanism can be controlled with high precision, making it possible to improve the classification accuracy.

[0110] In the classification apparatus described in Clause 6, the measured air pressure in the conduit is used for airflow velocity control. The air pressure in the conduit correlates with the airflow velocity within the sorting mechanism. Therefore, the airflow velocity within the sorting mechanism can be controlled with high precision, thereby improving the classification accuracy.

[0111] In the classification apparatus described in Clause 7, the measured air pressure within the sorting mechanism is used for airflow velocity control. The air pressure within the sorting mechanism is correlated with the airflow velocity within the sorting mechanism. Therefore, the airflow velocity within the sorting mechanism can be controlled with high precision, thereby improving the classification accuracy.

[0112] In the classification apparatus described in Clause 8, the measured air pressure at the supply port for supplying the powder and granular material to the sorting mechanism is used for air velocity control. The air pressure at the supply port correlates with the airflow velocity within the sorting mechanism. Therefore, the airflow velocity within the sorting mechanism can be controlled with high precision, thereby improving the classification accuracy.

[0113] In the classification apparatus described in Clause 9, a cyclone-type sorting mechanism is used as the sorting mechanism. Even in this case, the velocity of the airflow within the sorting mechanism can be controlled with high precision. As a result, it is possible to improve the classification accuracy.

[0114] In the classification apparatus described in Clause 10, the measured air pressure in the recovery pipe is used for airflow velocity control. Since the recovery pipe connects the cabinet and the sorting mechanism in a way that allows airflow to circulate, the pressure in the recovery pipe has a strong correlation with the airflow velocity in the sorting mechanism. Therefore, the airflow velocity in the sorting mechanism can be controlled with greater precision, and the classification accuracy can be further improved.

[0115] In the shot processing apparatus described in Clause 11, shot processing is performed by projecting abrasive material onto the workpiece. The resulting powder and granular material is supplied to a classifier, from which reusable abrasive material is selected and supplied back to the projection apparatus. Since a classifier capable of improving classification accuracy is used, abrasive material that does not contribute to shot processing can be accurately removed from the powder and granular material. As a result, the efficiency of shot processing can be improved.

[0116] In the shot processing apparatus described in Clause 12, shot processing is performed by projecting abrasive material onto the workpiece within the cabinet. The resulting powder and granular material is sent to a sorting mechanism, from which reusable abrasive material is selected and supplied to the projection apparatus. Since a classification apparatus capable of improving classification accuracy is used, abrasive material that does not contribute to shot processing can be accurately removed from the powder and granular material. As a result, the efficiency of shot processing can be improved. [Explanation of Symbols]

[0117] 1,1A...Shot processing device, 10...Cabinet, 20,20A...Projection device, 30...Recovery device, 33a...Outlet (supply port), 40,40A...Classification device, 41,41A...Sorting mechanism, 42...Conduit, 44...Dust collector, 45,45A...Measuring instrument, 46...Control device, 47...Damper, 48...Recovery pipe, 53...Fan motor, 81...Sensor body, 82...Pipe, 82a...Opening.

Claims

1. A sorting mechanism that uses airflow to separate groups of powders and granules, A dust collector that generates the aforementioned airflow, A conduit connecting the sorting mechanism and the dust collector so that the airflow can pass through, A measuring instrument for measuring the pressure of air containing powder and granular material, located upstream of the dust collector in the airflow path, A control device that controls the wind speed based on the measured values ​​measured by the measuring instrument, A classification device equipped with the following features.

2. The classification apparatus according to claim 1, wherein the measuring instrument includes a sensor body provided outside the flow path and a pipe connecting the flow path and the sensor body.

3. The classification apparatus according to claim 2, wherein the pipe has an opening in a direction intersecting the airflow.

4. The classification apparatus according to claim 2 or 3, wherein the pipe is made of a flexible material.

5. The classification apparatus according to any one of claims 1 to 3, wherein the pressure of the air is a differential pressure with respect to atmospheric pressure.

6. The classifier according to any one of claims 1 to 3, wherein the measuring instrument measures the pressure of the air inside the conduit.

7. The classification apparatus according to any one of claims 1 to 3, wherein the measuring instrument measures the pressure of the air within the sorting mechanism.

8. The classification apparatus according to any one of claims 1 to 3, wherein the measuring instrument measures the pressure of the air at the supply port for supplying the group of powders to the sorting mechanism.

9. The system further includes a recovery pipe that connects the cabinet containing the workpiece to be processed and the sorting mechanism so that the airflow can pass through it. The sorting mechanism is a cyclone-type sorting mechanism, according to any one of claims 1 to 3.

10. The classification apparatus according to claim 9, wherein the measuring instrument measures the pressure of the air in the recovery pipe.

11. A classification apparatus according to any one of claims 1 to 3, A projection device that performs shot blasting by projecting a projectile onto a workpiece, A recovery device for recovering the granular material generated by the shot processing and supplying the granular material to the classification device, Equipped with, The classification apparatus is a shot processing apparatus that selects reusable abrasive material from the group of powders and granules and supplies the abrasive material to the projection apparatus.

12. A classification apparatus according to claim 9, The aforementioned cabinet, A projection device that performs shot blasting by projecting a projectile onto the workpiece inside the cabinet, Equipped with, The recovery pipe carries the group of powder and granular material generated by the shot processing to the sorting mechanism via the airflow. The classification apparatus is a shot processing apparatus that selects reusable abrasive material from the group of powders and granules and supplies the abrasive material to the projection apparatus.

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