CN113518901A

CN113518901A - Powder processing method and powder processing device

Info

Publication number: CN113518901A
Application number: CN202080018476.1A
Authority: CN
Inventors: 帆山克明
Original assignee: Kawata Manufacturing Co Ltd
Current assignee: Kawata Manufacturing Co Ltd
Priority date: 2019-03-26
Filing date: 2020-03-16
Publication date: 2021-10-19
Also published as: JP2020159839A; WO2020196000A1

Abstract

The present invention relates to a powder particle processing method for estimating the storage amount of resin particles (9) in a storage tank (10) that stores the resin particles (powder particles) (9) as a processing object, a) passing an air flow through an air flow circulation path (air flow path) (31) including the storage tank (10) to pass the air flow through the resin particles (9); b) detecting a differential pressure between a pressure in the air flow circulation path (31) on the upstream side of the storage tank (10) and a pressure in the air flow circulation path (31) on the downstream side of the resin particles (9) in the storage tank (10); c) estimating the amount of resin particles (9) stored in the storage tank (10) based on the differential pressure detected in b).

Description

Powder processing method and powder processing device

Technical Field

The present invention relates to a powder processing method and a powder processing apparatus. More particularly, the present invention relates to a method and an apparatus for estimating the amount of a powder or granule retained.

Background

Conventionally, there has been known an apparatus for roughly understanding a storage amount of a powder or granule (powder and/or granule, hereinafter simply referred to as "powder or granule") in a storage tank for storing the powder or granule as a processing object. Such a device is disclosed in patent document 1, for example.

The drying device (powder processing device) disclosed in patent document 1 includes a drying hopper (10) for storing a powder material to be dried. The drying hopper (10) is provided with a hopper body (11) having a substantially cylindrical upper part and a substantially inverted conical lower part. The hopper body (11) is provided with level gauges (LV1, LV2, LV3, LV4) for detecting a plurality of levels as storage levels (l eve l) of the powdered or granular material in the drying hopper (10). These level gauges (LV1, LV2, LV3, LV4) are provided at predetermined intervals in the vertical direction.

In the drying apparatus disclosed in patent document 1, it is considered that which section of the adjacent level gauges (LV1, LV2, LV3, LV4) the storage level of the powdered or granular material is in is detected based on the detection result of the level gauges (LV1, LV2, LV3, LV 4). In the drying apparatus disclosed in patent document 1, the control of increasing or decreasing the storage level of the powdered or granular material is performed based on the detection result of the level gauges (LV1, LV2, LV3, LV 4).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012 and 63072

Disclosure of Invention

Technical problem to be solved by the invention

However, in the drying device described in patent document 1, a plurality of level meters are required to be provided in order to know the storage level of the powdered or granular material. The level gauge is generally expensive, and particularly when used in a drying device as in patent document 1, the level gauge is limited to a heat-resistant gauge that can be used in a high-temperature portion. Therefore, it is desired to estimate the amount of the particulate material to be stored at a lower cost. Further, if the hopper body is provided with a plurality of level meters as in the drying device described in patent document 1, it is necessary to process a plurality of positions of the hopper body, and the device becomes complicated, and there is room for improvement in this point. Further, in the drying device described in patent document 1, it is only known that the storage level of the particulate material is discrete within a certain range. In detail, since it is only possible to detect which section is located in the adjacent level gauge, the amount of the powder or granular material stored cannot be continuously known.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a powder and granular material processing method and a powder and granular material processing apparatus which can be realized simply and at low cost and which can continuously estimate the storage amount of powder and granular material.

Solution for solving the above technical problem

In order to solve the above-described problems, the invention 1 of the present application provides a powder and granular material processing method for estimating a storage amount of a powder and granular material in a storage tank inside which the powder and granular material as a processing object is stored, and including the following a) to c). In the a), the gas flow is caused to pass through the powder/granular material by passing the gas flow through a gas flow path including the retention tank. In the step b), a differential pressure between a pressure in the gas flow path on the upstream side of the storage tank and a pressure in the gas flow path on the downstream side of the powder/granular material in the storage tank is detected. In the step c), the storage amount of the powder or granule in the storage tank is estimated based on the differential pressure detected in the step b).

The invention 2 of the present application is the powder and granular material processing method according to the invention 1, wherein in the a), dry air is used as the airflow and is passed through the airflow path.

The 3 rd aspect of the present invention is the method for treating a powder or granule according to the 1 st or 2 nd aspect, wherein in the c) the storage amount of the powder or granule in the storage tank is estimated based on a calibration curve showing a correlation between the differential pressure and the storage amount.

The 4 th aspect of the present application is the powder/granular material processing method according to the 3 rd aspect, wherein in the c) the calibration curve is corrected based on a differential pressure detected when a storage amount of the powder/granular material in the storage tank is equal to or greater than a 1 st threshold value.

The 5 th aspect of the present application is the powder/granular material processing method according to the 4 th aspect, wherein in the c) the calibration curve is corrected based on a differential pressure detected when a storage amount of the powder/granular material in the storage tank is less than a 2 nd threshold value which is smaller than a 1 st threshold value.

The 6 th aspect of the present invention is the method for processing a powder or granular material according to any one of the 3 rd to 5 th aspects, wherein in the c), the calibration curve is corrected as long as a change amount of the storage amount of the powder or granular material in the storage tank is smaller than a predetermined amount.

The 7 th aspect of the present invention is the method for treating powder or granule according to any one of the 1 st to 6 th aspects, wherein d) is as follows. In the d), after the c), information related to the storage amount estimated in the c) is displayed on a display unit.

The 8 th aspect of the present application is the method for processing powder and granular material according to any one of the 3 rd to 6 th aspects, wherein in the c) the storage amount is estimated using any one of a plurality of calibration curves corresponding to a plurality of types of powder and granular material having different properties.

The 9 th aspect of the present application provides a powder/granular material processing apparatus including: a retention tank, an air flow path, a differential pressure detection means, and a retention amount estimation means. The storage tank stores therein powder or granular material as a treatment object. The air flow path is an air flow path through which an air flow passes, and includes the retention tank. The differential pressure detection means detects a differential pressure between the pressure in the airflow path on the upstream side of the storage tank and the pressure in the airflow path on the downstream side of the powder/granular material in the storage tank. The storage amount estimating means estimates the storage amount of the powder or granule in the storage tank based on the detection result of the differential pressure detecting means.

The 10 th aspect of the present invention is the powder/granular material processing apparatus according to the 9 th aspect of the present invention, wherein the storage amount estimating means outputs an output signal corresponding to the estimated storage amount.

The 11 th aspect of the present invention is the powder and granular material processing apparatus according to the 9 th or 10 th aspect of the present invention, wherein the storage amount estimating means estimates the storage amount of the powder and granular material in the storage tank based on a calibration curve showing a correlation between the differential pressure and the storage amount. The powder/granular material processing apparatus includes a storage device capable of storing data relating to the calibration curve for classifying types of powder/granular materials having different properties for each type.

The 12 th aspect of the present invention is the powder/granular material processing apparatus according to any one of the 9 th to 11 th aspects of the present invention, further comprising an air volume adjusting mechanism for maintaining a constant flow volume of the air flow in the air flow path.

The 13 th aspect of the present invention is the powder/granular material processing apparatus according to the 10 th aspect of the present invention, further comprising an alarm means for giving an alarm based on the output signal.

The 14 th aspect of the present invention is the powder/granular material processing apparatus according to the 13 th aspect of the present invention, wherein the notification means is capable of changing a level of the reserve amount at the time of issuing an alarm.

Effects of the invention

According to the 1 st to 14 th aspects of the present invention, there are provided a powder and granular material processing method and a powder and granular material processing apparatus which can be realized simply and at low cost and which can continuously estimate the amount of the powder and granular material stored.

In particular, according to the invention 2 of the present application, the drying treatment of the powder or granule can be performed in the storage tank while taking into consideration the storage amount of the powder or granule in the storage tank. In particular, when the storage tank is a drying hopper, it is advantageous because the storage amount can be estimated using dry air originally used for drying. In this case, the storage amount of the powder or granule in the storage tank can be estimated with a simple configuration or with a small change to the existing equipment.

In particular, according to the 3 rd aspect of the present invention, the storage amount of the powder or granule in the storage tank can be estimated with high accuracy by using the calibration curve.

In particular, according to the 4 th aspect of the present invention, the calibration curve can be appropriately corrected in consideration of the pressure loss when the storage amount of the powder or granule in the storage tank is equal to or greater than the 1 st threshold (for example, full hopper). As a result, the storage amount of the powder or granule in the storage tank can be estimated with higher accuracy.

In particular, according to the 5 th aspect of the present invention, the calibration curve can be appropriately corrected in consideration of the pressure loss when the amount of the powder or granule stored in the storage tank is smaller than the 2 nd threshold (for example, empty bucket). As a result, the storage amount of the powder or granule in the storage tank can be estimated with higher accuracy.

In particular, according to the invention 6 of the present application, the calibration curve can be corrected and updated as long as the storage amount of the powder or granule in the storage tank is kept substantially constant. As a result, a calibration curve clearly reflecting the correlation between the differential pressure and the retention amount can be obtained.

In particular, according to the 7 th aspect of the present invention, the operator can visually confirm the storage amount of the powder or granule in the storage tank. As a result, the operator can easily perform an appropriate operation according to the storage amount of the powder and granular material in the storage tank.

In particular, according to the 8 th aspect of the present invention, the storage amount of the powder or granule in the storage tank can be estimated using a calibration curve appropriately selected according to the type of the powder or granule. As a result, the storage amount of the powder or granule in the storage tank can be estimated with higher accuracy.

In particular, according to the 10 th aspect of the present invention, the operator can know the amount of the powder or granule stored in the storage tank based on the output signal. As a result, the operator can easily perform an appropriate operation according to the storage amount of the powder and granular material in the storage tank.

In particular, according to the 11 th aspect of the present application, for example, the calibration curves corresponding to the respective types of the powder and granular body can be statistically corrected based on the data on the calibration curves stored by the types.

In particular, according to the 12 th aspect of the present application, the storage amount of the powder or granule in the storage tank can be estimated with high accuracy without being affected by the volume of air flowing through the airflow path.

In particular, according to the 13 th aspect of the present invention, the operator can know the storage amount of the powder or granule in the storage tank by an alarm.

In particular, according to the 14 th aspect of the present application, it is possible to provide that an alarm is issued when the storage amount of the powder or granule in the storage tank reaches an arbitrary level. Therefore, the alarm level of the powder and granular body processing apparatus can be customized according to the purpose of the operator.

Drawings

Fig. 1 is a schematic diagram showing a schematic configuration of a powder/granular material processing apparatus according to embodiment 1.

Fig. 2 is a block diagram showing an electrical configuration of the powder/granular material processing apparatus according to embodiment 1.

Fig. 3 is a flow chart illustrating a process for generating and updating a calibration curve.

Fig. 4 is a flowchart showing a process for updating the calibration curve.

Fig. 5 is a flowchart showing a process of estimating the storage amount of the powder based on the calibration curve and the current differential pressure.

Fig. 6 is a conceptual diagram illustrating a process of obtaining the current storage amount of the powder or granule based on the calibration curve and the current differential pressure.

Fig. 7 is a block diagram showing an electrical configuration of the powder/granular material processing apparatus according to embodiment 2.

Fig. 8 is a graph showing the results of an experiment in which the correlation between the differential pressure before and after the storage tank and the storage amount of the powder or granule in the storage tank was examined.

Detailed Description

Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings.

<1 > embodiment 1 >

<1-1. integral constitution of powder and granular Material processing apparatus >

The powder/granular material processing apparatus 1 of the present embodiment uses powder/granular material as a processing object. The powder/granular material processing apparatus 1 is an apparatus for performing a process of drying the resin pellets 9 as powder/granular materials in advance before they are put into a subsequent molding machine. Fig. 1 schematically shows the structure of a powder processing apparatus 1. As shown in fig. 1, a powder/granular material processing apparatus 1 according to the present embodiment includes: a storage tank 10, a material supply mechanism 20, and an air circulation mechanism 30. The subsequent molding machine is, for example, an injection molding machine for molding a resin, but is not limited thereto, and may be other processing equipment such as an extrusion molding machine, an blow molding machine, and a compression molding machine.

The storage tank 10 is a container that stores therein the resin pellets 9 before drying as the object to be processed. The storage tank 10 includes: a substantially cylindrical side wall portion 11; a funnel-shaped bottom portion 12 having a radial dimension gradually decreasing downward from the lower end of the side wall portion 11; and a top plate 13 for closing the upper end of the side wall 11. A space for storing the resin pellets 9 and drying the resin pellets by heating is provided inside the storage tank 10. A supply hopper 21 described later is provided in the top plate 13 of the storage tank 10. A mechanism (not shown) for conveying (discharging) the processed powder or granule to the outside by pneumatic conveyance is connected to the lower end of the bottom 12 of the storage tank 10. The storage tank 10 may be set on a floor of a factory or the like, or may be set on a material input portion of a molding machine.

The material supply mechanism 20 is a mechanism for supplying the resin pellets 9 before drying to the storage tank 10. The material supply mechanism 20 of the present embodiment includes: a supply hopper 21, a tubular supply pipe 22, a supply valve 23, a tank 24, and a conveyance blower 27.

The supply hopper 21 is a container that temporarily stores the resin pellets 9 before supplying the resin pellets 9 to the storage tank 10. The supply hopper 21 is connected to the storage tank 10 through an openable and closable inlet 25 provided in the top plate 13 of the storage tank 10.

The supply pipe 22 is a series of pipes connecting the supply hopper 21 to the tank 24 containing the resin pellets 9 before drying. The upstream end of the supply pipe 22 is connected to a tank 24. The downstream end of the supply pipe 22 is connected to a side wall of the supply hopper 21.

The supply valve 23 is an electromagnetic valve and is switchable between a closed state in which a flow path in the supply pipe 22 is closed and an open state in which the flow path is opened. When the supply valve 23 is opened, the tank 24 and the supply hopper 21 are communicated with each other, and the resin pellets 9 in the tank 24 can be supplied to the supply hopper 21. In this state, the resin pellets 9 in the tank 24 are pneumatically conveyed to the supply hopper 21 through the supply pipe 22 by driving the conveyance blower 27 shown in fig. 1. On the other hand, when the supply valve 23 is closed, the inside of the supply hopper 21 is kept substantially airtight. Therefore, while the lower end portion of the bottom portion 12 of the storage tank 10 is also closed in addition to the supply valve 23, the storage tank 10 is substantially blocked from the outside air.

The supply valve 23 is not limited to an electromagnetic valve, and may be a valve that is pneumatically driven or a valve that is driven by another driving method. The valve may have another shape such as a ball valve or a gate valve. In addition, the supply valve 23 may be omitted when it is not necessary to block the outside air from the material supply mechanism 20.

The air flow circulating mechanism 30 is a mechanism for circulating the air flow to the storage tank 10. The air circulation mechanism 30 of the present embodiment feeds hot air, which is heated air, to the storage tank 10. In particular, the airflow circulation mechanism 30 of the present embodiment heats the gas discharged from the storage tank 10 and feeds the heated gas into the storage tank 10 again. In other words, the air flow circulation mechanism 30 converts the exhaust gas (air flow) from the storage tank 10 into hot air and circulates the hot air to the storage tank 10 again. The airflow circulation mechanism 30 includes: an air circulation path 31, a filter 32, a cooler 33, a drying blower 34, and a moisture adsorption unit 35 heater 36.

The air flow circulation path 31 is a series of pipes for returning the gas (air flow) discharged from the storage tank 10 to the storage tank 10 again and circulating the gas. As shown in fig. 1, the upstream end of the airflow circulation path 31 is connected to the upper portion of the side wall 11 of the storage tank 10. Further, the downstream end of the airflow circulation path 31 opens inside the bottom 12 of the storage tank 10. A filter 32, a cooler 33, a drying blower 34, a moisture adsorption unit 35, and a heater 36 are provided in this order from the upstream side toward the downstream side on the path of the airflow circulation path 31. With these configurations, the airflow circulation path 31 forms an "airflow path" including the storage tank 10.

The drying blower 34 has a known configuration having a plurality of blades, for example. The drying blower 34 sucks the gas in the retention tank 10 from the upstream end of the gas flow circulation path 31 by rotating the plurality of blades, and generates a gas flow toward the downstream end.

The filter 32 captures fine dust sucked into the airflow circulation path 31 from the storage tank 10. This prevents fine dust from being captured by the downstream equipment.

The cooler 33 cools the gas sucked from the retention tank 10 into the gas flow circulation passage 31 by a known method such as heat exchange. By cooling the gas with the cooler 33, moisture is easily removed from the gas.

The moisture adsorption unit 35 is a device that adsorbs moisture contained in the gas cooled by the cooler 33. As the moisture adsorbing means 35, various known methods can be used, and for example, a honeycomb-shaped ceramic body can be used. In this case, the ceramic body may be made to contain zeolite or the like having a property of adsorbing moisture.

The heater 36 heats the gas whose moisture has been adsorbed and dehumidified by the moisture adsorbing unit 35 by a known method such as an electric heater. The gas that has reached the heater 36 through the path in the gas flow circulation path 31 is heated by the heater 36 to become hot air. Then, the hot air is blown out into the storage tank 10 from the air outlet 46 provided at the downstream end of the airflow circulation path 31. The blow-out port 46 is disposed at a position at a height that can be buried in the resin pellets 9 accumulated in the storage tank 10 when stable.

In the powder/granular material processing apparatus 1 configured as described above, the resin pellets 9 stored in the storage tank 10 are dried by feeding hot air into the layer in which the resin pellets 9 are stacked. That is, the moisture contained in the resin pellets 9 is transferred to the dry hot air, and the gas in the retention tank 10 is in a state of containing relatively much moisture. The gas containing a large amount of moisture passes through the gas flow circulation path 31 from the upstream side to the downstream side in accordance with the gas flow generated by the drying blower 34, is dehumidified during this period, becomes hot air again, and is sent to the storage tank 10. By such circulation of the gas, the drying process of the resin pellets 9 is advanced in the storage tank 10.

When the drying process is completed or a material is required for a subsequent apparatus such as a molding machine, the dried resin pellets 9 are supplied to the subsequent apparatus. When the amount of resin pellets 9 accumulated in the storage tank 10 becomes smaller than the predetermined level, the conveyance blower 27 is operated to generate a negative pressure to the supply hopper 21 and then the supply valve 23 is temporarily opened, so that the resin pellets 9 are pneumatically conveyed from the tank 24 to the supply hopper 21. Thereafter, the inlet 25 is opened, and the resin pellets 9 before the subsequent drying are filled in the storage tank 10.

Various techniques for determining the amount of the powder or granule stored in the storage tank are considered. As a specific example, a configuration may be considered in which a plurality of level gauges are provided at vertically spaced intervals in the storage tank. However, since level gauges are generally expensive, a method that can be implemented with lower costs is desired. As another specific example, a configuration may be considered in which a single level gauge is provided so as to be vertically displaceable with respect to the storage tank. However, in such a configuration, improvement is desired in that the apparatus becomes complicated. More specifically, in any of the above-described embodiments, it is only possible to determine whether or not the powder or granule is located at the position where the level gauge is installed, and therefore it is still difficult to continuously know the amount of the powder or granule stored.

<1-2 > construction specific to the present embodiment

In this regard, the powder based granules processing apparatus 1 of the present embodiment has a unique configuration for enabling the storage amount of the resin pellets 9 to be continuously estimated, while being easily and inexpensively realized. Specifically, the powder/granular material processing apparatus 1 includes: a differential pressure sensor 40, a 1 st level gauge 51, a 2 nd level gauge 52, a temperature sensor 70, an air gauge 80, and a controller 90. These parts will be explained below.

The differential pressure sensor 40 shown in fig. 1 is an embodiment of the "differential pressure detection means". A differential pressure sensor 40 is provided midway along the path of a series of tubular measurement lines 41. One end of the measurement line 41 is connected to a position P1 on the downstream side of the heater 36 midway along the path of the airflow circulation path 31. The other end of the branch passage 41 is connected to a position P2 on the upstream side of the filter 32 in the airflow circulation passage 31. Thus, the differential pressure sensor 40 detects the difference between the pressure of the gas in the gas flow circulation passage 31 at the position P1 on the upstream side of the storage tank 10 and the pressure of the gas in the gas flow circulation passage 31 at the position P2 on the downstream side of the storage tank 10. In other words, the differential pressure sensor 40 can detect the pressure loss in the storage tank 10. The positions of P1 and P2 are not limited to the above positions. Specifically, P1 may be any position as long as it is a position between drying blower 34 and outlet 46. The position of P2 may be any position as long as it is a position between the upper surface of the resin pellet 9 in the storage tank 10 and the drying blower 34.

The 1 st level gauge 51 is a sensor for detecting a full level (full level, upper limit level) of the powder or granule stored in the storage tank 10 when the storage level is full. The 1 st level gauge 51 is attached to the ceiling portion 13 of the storage tank 10.

The 2 nd level gauge 52 is a sensor for detecting when the storage amount of the powder or granule in the storage tank 10 is an empty bucket (lower limit level, level of the necessary material). The 2 nd level gauge 52 is attached to a lower portion of the side wall portion 11 of the storage tank 10.

The temperature sensor 70 detects the temperature of the exhaust gas from the storage tank 10. The temperature sensor 70 of the present embodiment is attached to a position immediately after the air flow has flowed out of the storage tank 10 of the air flow circulation path 31.

The air flow meter 80 is a well-known measuring device that can detect the flow rate of the gas passing through the flow path. The air gauge 80 is provided between the moisture adsorption unit 35 and the heater 36 in the flow path of the gas. Thereby, the air flow meter 80 detects the flow rate of the gas flowing into the retention tank 10. The air flow meter 80 measures the flow rate by, for example, obtaining a differential pressure between pipes having different pipe diameters such as venturi tubes, but may be a meter of another flow rate measurement method such as a pitot tube. Further, the wind speed of the duct may be measured by using an anemometer of a hot-wire type, and the measured wind speed may be converted into a flow rate.

<1-3. Electrical construction of apparatus for treating powder and granular Material >

Hereinafter, the configuration of the control system of the powder/granular material processing apparatus 1 according to the present embodiment will be briefly described with reference to fig. 2. Fig. 2 is a block diagram showing the electrical configuration of each part of the powder/granular material processing apparatus 1.

The control unit 90 shown in fig. 1 and 2 is a mechanism for controlling the operation of each unit of the powder/granular material processing apparatus 1. The control unit 90 is an embodiment of the "storage amount estimating means". As shown in fig. 2, the controller 90 is electrically connected to the supply valve 23, the conveyor blower 27, the cooler 33, the drying blower 34, the moisture adsorbing unit 35, the heater 36, the differential pressure sensor 40, the 1 st level gauge 51, the 2 nd level gauge 52, the temperature sensor 70, the air gauge 80, and the like. The control unit 90 of the present embodiment is constituted by a computer having an arithmetic processing unit such as a CPU or a memory (storage unit) 91. However, the present invention is not limited to this, and the control unit 90 may be configured by an electronic circuit. The control unit 90 controls the operations of the above-described units based on a preset program or an input signal from the outside. That is, the above-described hardware and software cooperate with each other to cause each part of the powder and granular material processing apparatus 1 to function. This advances the processing of the resin pellets 9 in the powder and granular material supply apparatus 1. The control unit 90 performs a process of estimating the amount of the powder or granule stored in the storage tank 10 so that the resin pellets 9 can be appropriately processed.

<1-4. initiation of treatment of powder and granular Material >

First, a flow of the process when the control unit 90 starts the process of the resin pellets 9 will be briefly described. First, the control unit 90 opens the supply valve 23 after operating the conveyance blower 27. Thereby, the undried resin pellets 9 in the tank 24 are fed to the supply hopper 21. After that, when the conveyance blower 27 is stopped, the inlet 25 is opened, and the resin pellets 9 in the supply hopper 21 are collectively supplied to the inside of the storage tank 10. Thereby, the storage tank 10 is filled with the resin pellets 9 in a substantially full bucket. Thereafter, the drying blower 34 is driven to supply hot air into the storage tank 10. Thereby, the heating and drying of the resin pellets 9 in the storage tank 10 are started.

Here, there is a correlation between the differential pressure of the gas before and after (upstream and downstream sides) the storage tank 10 and the storage level of the resin pellets 9 in the storage tank 10. Specifically, the storage level of the resin pellets 9 in the storage tank 10 is proportional to the magnitude of the differential pressure between the front and rear of the storage tank 10. The slope of the linear function showing the correlation between the magnitude of the differential pressure before and after the storage tank 10 and the storage level of the resin pellets 9 in the storage tank 10 differs depending on the properties (particle diameter, shape, etc.) of the resin pellets 9. In the present embodiment, the storage amount of the resin particles 9 in the storage tank 10 is estimated from such a viewpoint. Specifically, a calibration curve L described later is generated, and the storage level of the resin pellets 9 in the storage tank 10 is estimated based on the calibration curve L.

<1-5. creation of calibration Curve >

After the start of the processing of the resin pellets 9, the control unit 90 repeats the processing of fig. 3 and 4 in parallel. Thus, the calibration curve L is generated, and is updated (corrected) every time the empty bucket or the full bucket is reached in the storage tank 10 in a state in which the predetermined condition is satisfied.

Fig. 3 is a flowchart showing a process repeated by the control unit 90 to generate and update the calibration curve L. As shown in fig. 3, the control unit 90 determines whether or not the state in which the storage tank 10 is filled with the resin pellets 9 in a full bucket continues for a predetermined time or longer (step S101). Specifically, the control portion 90 determines whether or not the state in which the 1 st level gauge 51 detects that the storage level of the resin pellets 9 has reached the full level continues for a predetermined time or longer.

If the full bucket state in the storage tank 10 does not continue for a predetermined time or longer as a result of the determination in step S101 (no in step S101), the control unit 90 repeats the determination process in step S101 until the condition is satisfied next time.

If the storage tank 10 is kept full of buckets for a predetermined time or longer as a result of the determination in step S101 (yes in step S101), the control unit 90 then determines whether or not the amount of change in the temperature of the airflow flowing out of the storage tank 10 is less than the threshold value for the predetermined time (step S102). Specifically, the control section 90 determines whether or not the amount of change in the temperature in the storage tank 10, which is output from the temperature sensor 70, is smaller than a threshold value.

When the amount of change in the temperature of the air flow flowing out of the storage tank 10 is smaller than the threshold value within the predetermined time period as a result of the determination in step S102 (yes in step S102), it is considered that both the storage amount and the temperature of the resin pellets 9 continue to be in a stable state in the storage tank 10. In other words, it is considered that the drying is still and advanced in the retention tank 10. In this case, it is estimated that the correlation between the differential pressure before and after the storage tank 10 and the storage amount in the storage tank 10 clearly has a proportional relationship without being affected by the increase and decrease in the temperature and the storage amount. In this case, the control unit 90 acquires the differential pressure D1 output from the differential pressure sensor 40 (step S103). The method for determining whether or not the state of the resin pellets 9 in the storage tank 10 is stable may be a method other than the amount of change in the temperature of the exhaust gas, or may be a method based on the temperature of another location such as the material temperature in the storage tank 10. For example, the time index may be acquired in advance so that it can be determined that the material has stabilized after a certain time has elapsed immediately after the replenishment of the material from the material supply mechanism 20, and the determination may be performed based on the time index. Further, it may be determined that the drying is continuously and stably performed in the storage tank 10 after a predetermined time has elapsed from the start of the secondary transportation to the molding machine side.

After step S103, the control unit 90 generates a calibration curve L using a combination of the volume V1 (100%) of the storage tank 10 at the full bucket and the differential pressure D1 obtained at step S103 (step S104). Specifically, a calibration curve L passing through the coordinates (V1, D1) is generated by setting the x-axis as the volume (%) of the storage tank 10 and the y-axis as the differential pressure before and after the storage tank 10. In addition, in the case where the calibration curve L has not been generated before, a default value is used as the value of the y-intercept. On the other hand, when the calibration curve L is generated previously, the calibration curve L passing through the coordinates (V0, D0) described later is generated in addition to the coordinates (V1, D1).

After step S104, the control section 90 stores the latest calibration curve L in the memory 91 to be used in the subsequent processing of the resin pellets 9 and the like (step S105). At this time, in the present embodiment, when the calibration curve L generated previously is stored in the memory 91, it is updated to the latest calibration curve L.

Fig. 4 is a flowchart showing the process repeatedly performed by the control unit 90 to update the calibration curve L. As shown in fig. 4, the control unit 90 determines whether or not the empty state in the storage tank 10 continues for a predetermined time or longer (step S201). Specifically, the control portion 90 determines whether or not the state in which the 2 nd level gauge 52 detects that the storage level of the resin particles 9 has reached the lower limit level or less has continued for a predetermined time or longer.

If the determination result in step S201 indicates that the empty tank 10 does not continue for a predetermined time or longer (no in step S201), control unit 90 repeats the determination process in step S201 until the condition is satisfied next time.

If the empty state in the storage tank 10 continues for a predetermined time or longer as a result of the determination in step S201 (yes in step S201), the control unit 90 then determines whether or not the amount of temperature change in the storage tank 10 is less than the threshold value for the predetermined time (step S202). Specifically, the control section 90 determines whether or not the amount of change in the temperature in the storage tank 10, which is output from the temperature sensor 70, is smaller than a threshold value.

If the amount of change in the temperature in the storage tank 10 during the predetermined time period is smaller than the threshold value as a result of the determination in step S202 (yes in step S202), it is considered that both the storage amount and the temperature of the resin pellets 9 in the storage tank 10 continue to be in a stable state. In this case, it is estimated that the correlation between the differential pressure before and after the storage tank 10 and the storage amount in the storage tank 10 is less likely to be affected by the increase and decrease in the temperature and the storage amount. In this case, the control unit 90 acquires the differential pressure D0 output from the differential pressure sensor 40 (step S203). That is, the differential pressure D0 corresponds to the differential pressure at the time of empty bucket.

After step S203, the control unit 90 updates the calibration curve L using a combination of the volume V0 (0%) of the retention tank 10 during empty bucket and the differential pressure D0 acquired at step S203 (step S204). In detail, the coordinates (V0, D0) are added as drawing points to the calibration curve L generated previously. That is, the calibration curve L is corrected and updated so as to pass through both the coordinates (V1, D1) acquired most recently and the coordinates (V0, D0) acquired this time.

After step S204, the control portion 90 stores the latest calibration curve L in the memory 91 (step S205) to be used in the subsequent processing of the resin pellets 9 and the like. At this time, in the present embodiment, when the calibration curve L generated previously is stored in the memory 91, it is updated to the latest calibration curve L.

In this manner, in the present embodiment, controller 90 corrects calibration curve L based on differential pressure D1 at the full fill time and differential pressure D0 at the empty fill time. This makes it possible to appropriately correct the calibration curve L in consideration of the pressure loss when the amount of the resin pellets 9 stored in the storage tank 10 is full and empty.

The method for obtaining the differential pressure D0 at the time of empty bucket may be a method other than the above-described steps. For example, unlike the full-fill differential pressure D1, the empty-fill differential pressure D0 has small fluctuations due to the material, and therefore the empty-fill differential pressure D0 can be obtained in advance by a preliminary test or the like and used. In this case, the 2 nd level gauge 52 can be omitted. The differential pressure D0 during empty bucket may be manually input. Alternatively, the empty bucket position may be freely set by setting the empty bucket at an arbitrary storage amount and using the differential pressure at that position as the differential pressure at empty bucket D0.

<1-6. estimation of storage amount of powder/granule >

Next, the processing performed by the control unit 90 to estimate the amount of the resin pellets 9 stored in the storage tank 10 will be described with reference to fig. 5 and 6.

Fig. 5 is a flowchart showing the process repeatedly performed by the control section 90 in order to continuously estimate the amount of the resin pellets 9 stored in the storage tank 10. As shown in fig. 5, the control unit 90 first acquires the current differential pressure D between the front and rear of the storage tank 10 (step S301). Specifically, the control unit 90 acquires the current differential pressure D output from the differential pressure sensor 40.

After step S301, the control unit 90 reads the latest calibration curve L from the memory 91 (step S302).

After step S302, the control unit 90 acquires the storage amount S (estimated value) of the resin pellets 9 in the storage tank 10 based on the calibration curve L and the current differential pressure D (step S303). Conceptually, as shown in fig. 6, the value of the x coordinate when the y coordinate is D is read from a set of an infinite number of points arranged on the calibration curve L. The value of the x-coordinate is an estimated value (S) of the amount of resin pellets 9 currently stored in the storage tank 10.

After step S303, the control unit 90 outputs the estimated storage amount S to the display unit. Display deviceThe display unit may be, for example, a control panel (not shown) of the powder/granular material processing apparatus 1. However, the present invention is not limited to this, and for example, a display of an external computer electrically connected to the powder/granular material processing apparatus 1 may be used as the "display unit". Alternatively, a display provided in a device (forming machine in the present embodiment) subsequent to the powder/granular material processing device 1 may be used as the "display unit". The storage amount S may be displayed as volume (%) or (L), (m)³). Alternatively, the information on the volume density of the resin pellets 9 may be input to the control unit 90, and the volume (%) may be converted into weight (kg) and displayed in units of weight (kg). In addition, the display is not limited to the display by numerical values, and abstract expressions such as "large", "medium", "small", "full fight", "empty fight" and "empty fight after X minutes" may be used. Alternatively, the storage level in the storage tank 10 may be shown by an illustration, or a variable arrow may be shown in the illustration of the hopper, or the level may be expressed by a color tone.

As described above, the method for treating powder or granule disclosed in the present embodiment includes the steps of: and a step of passing the gas flow through the resin particles (powder particles) 9 by passing the gas flow through a gas flow path (gas flow circulation path 31) including the storage tank 10. The method for treating a powder or granule includes the steps of: a step of detecting a differential pressure D between the pressure in the airflow path on the upstream side of the storage tank 10 and the pressure in the airflow path on the downstream side of the resin pellets 9 in the storage tank 10 (step S301). The powder/granular material processing method further includes a step of estimating the storage amount S of the resin particles 9 in the storage tank 10 based on the current differential pressure D (step S303). Thus, the storage amount S of the resin pellets 9 in the storage tank 10 can be estimated with a simple and inexpensive configuration without providing a large number of level meters or the like.

In the method for treating powder or granule disclosed in the present embodiment, dry air (gas) is passed through the gas flow path as a gas flow. This allows the drying process of the resin pellets 9 to be performed in the storage tank 10 while taking into account the storage amount S of the resin pellets 9 in the storage tank 10. Specifically, for example, the following operations can be performed: that is, when the storage amount S is too small, the output of the drying blower 34 is reduced to perform the energy saving operation, whereas when the storage amount S is too large, the output of the drying blower 34 is increased to perform the heating and drying strongly. Further, by using the present invention for the storage tank 10 as a drying hopper, the amount of the resin pellets 9 stored can be estimated by directly using the air originally used for drying. In this way, the storage amount of the resin pellets 9 in the storage tank 10 can be estimated with a simple configuration or with a small change to existing equipment.

In the powder/granular material processing method disclosed in the present embodiment, the current storage amount S of the resin pellets 9 in the storage tank 10 is estimated based on the calibration curve L showing the correlation between the differential pressure before and after the storage tank 10 and the storage amount of the resin pellets 9 in the storage tank 10 (step S303). By using the calibration curve L in this manner, the storage amount S of the resin pellets 9 in the storage tank 10 can be estimated continuously and with high accuracy.

In the powder/granular material processing method disclosed in the present embodiment, the calibration curve L is updated (corrected) based on the differential pressure D1 detected when the amount of resin pellets 9 stored in the storage tank 10 is equal to or greater than the 1 st threshold (full hopper) (step S104). Thus, the calibration curve can be appropriately corrected in consideration of the pressure loss when the storage amount of the resin pellets 9 in the storage tank 10 is equal to or greater than the 1 st threshold (full bucket in the present embodiment). As a result, the storage amount S of the resin pellets 9 in the storage tank 10 can be estimated with higher accuracy.

In the powder/granular material processing method disclosed in the present embodiment, the calibration curve L is updated (corrected) based on the differential pressure D0 detected when the amount of the powder/granular material stored in the storage tank 10 is less than the 2 nd threshold (empty bucket) which is less than the 1 st threshold (step S204). Thus, the calibration curve can be appropriately corrected in consideration of the pressure loss when the storage amount of the resin pellets 9 in the storage tank 10 is smaller than the 2 nd threshold (in the present embodiment, the empty bucket). As a result, the storage amount S of the resin pellets 9 in the storage tank 10 can be estimated with higher accuracy.

In the powder/granular material processing method disclosed in the present embodiment, the calibration curve L is corrected as long as the amount of change in the storage amount of the resin pellets 9 in the storage tank 10 and the amount of change in the temperature are respectively smaller than the predetermined amounts (yes in step S102 and yes in step S202). Thereby, the storage amount of the resin pellets 9 in the storage tank 10 is kept substantially constant, and the calibration curve L can be corrected and updated as long as the temperature change is small. As a result, a calibration curve clearly reflecting the correlation between the differential pressure D and the reserve amount S can be obtained.

In the method for processing powder or granular material disclosed in the present embodiment, information on the estimated storage amount S is displayed on the display unit (step S304). This enables the operator to visually confirm the amount of resin pellets 9 stored in the storage tank 10. As a result, the operator can easily perform an appropriate operation according to the amount of the resin pellets 9 stored in the storage tank 10. Specifically, for example, the operator can advance the supply of the resin particles 9 to the powder/granular material processing apparatus 1 so that the resin particles 9 in the powder/granular material processing apparatus 1 are just empty at the end of production by reversing the supply amount at the secondary side based on the storage amount S visually recognized.

The powder/granular material processing apparatus 1 disclosed in the present embodiment includes: a storage tank 10, an air flow path (air flow circulation means 30), a differential pressure sensor (differential pressure detection means) 40, and a control unit (storage amount estimation means) 90. This makes it possible to estimate the storage amount S of the resin pellets 9 in the storage tank 10 with a simple configuration while suppressing the cost.

In the powder/granular material processing apparatus 1 disclosed in the present embodiment, the differential pressure sensor 40 is provided not on the side wall 11 of the storage tank 10 but on the middle part of the airflow path (airflow circulation path 31). Therefore, the powder/granular material processing method (the method of estimating the storage level) can be easily introduced without performing complicated processing on the side wall portion 11 of the storage tank 10.

<2 > embodiment 2 >

Hereinafter, the powder based granules processing apparatus 2 according to embodiment 2 will be described mainly with reference to fig. 7 and 8. In the powder/granular material processing apparatus 1 according to embodiment 1, the single calibration curve L is automatically updated every time the storage tank 10 is empty or full in a state in which a predetermined condition is satisfied. In contrast, in the powder/granular material processing apparatus 2 according to embodiment 2, the calibration curve L is generated and stored for each of the plurality of types of resin particles 9 having different properties, and the calibration curve L is statistically corrected.

Hereinafter, the components (portions) constituting the powder/granular material processing apparatus 2 according to embodiment 2 have the same configurations and functions as those described in embodiment 1, and the same reference numerals are given thereto, and redundant description thereof is omitted.

The control unit 90 shown in fig. 7 is a mechanism for controlling the operation of each unit of the powder/granular material processing apparatus 2. The control unit 90 is an embodiment of the "storage amount estimating means" and is also an embodiment of the "air volume adjusting means". The control part 90 is electrically connected to the supply valve 23, the cooler 33, the drying blower 34, the moisture adsorption unit 35, the heater 36, the differential pressure sensor 40, the 1 st level gauge 51, the 2 nd level gauge 52, the temperature sensor 70, and the air gauge 80, respectively. The control unit 90 of the present embodiment is electrically connected to the input unit 93 and the notification mechanism 97, respectively.

<2-1. initiation of treatment of powder and granular Material >

First, a flow of processing when the processing of the resin pellets 9 is started by the powder/granular material processing apparatus 2 will be briefly described. First, the operator sets the storage tank 10 to an empty state. Next, the operator sets the resin pellets 9 as the processing object of this time in the tank 24. After the resin pellets 9 of this time are set in the tank 24, the operator operates the input unit 93 to input the type of the resin pellets 9 of this time (for example, "type a"). Then, the powder/granular material processing apparatus 2 is started. Thereby, the control unit 90 opens the supply valve 23 and operates the conveyance blower 27. In this way, the undried resin pellets 9 in the tank 24 are fed to the supply hopper 21. After that, when the conveyance blower 27 is stopped, the inlet 25 is opened, and the resin pellets 9 in the supply hopper 21 are supplied into the storage tank 10 at once. Thus, the storage tank 10 is filled with the resin pellets 9 almost fully, but the data of the differential pressure D1 at this time is not stored in the memory 91. That is, when the storage tank 10 is initially full, the recording of the differential pressure D1 is abandoned. Next, data of the differential pressure D1(D0) when the storage tank 10 is filled with the resin pellets 9 to full or empty is stored in the memory 91. This is because, at the time point when the storage tank 10 is first filled, the conditions such as the temperature in the storage tank 10 are unstable, and it is not appropriate to generate the calibration curve.

<2-2. creation of calibration Curve >

The memory 91 of the control unit 90 stores (stores) data of the differential pressure D1(D0) when the resin pellets 9 are filled in the storage tank 10 in a full bucket or in an empty bucket, in classification for different types of resin pellets 9 having different properties. That is, for example, when the operator inputs 3 types (type a, type B, and type C) of the resin pellets 9 to the input unit 93, data of the differential pressure D1(D0) between the full-bucket time and the empty-bucket time is stored for each type. Further, the operation parameters of the equipment, such as other measured values of temperature, pressure, and air volume, the frequency of the blower, the output of the heater, and the input/output signals from other equipment, are also recorded at the same time.

Then, for example, when there are a plurality of pieces of data of the differential pressure D1 at the time of full-filling of the resin pellets 9 of the type a, the controller 90 statistically processes the pieces of data to calculate the coordinates (V1, D1). Specifically, the coordinates (V1 ', D1') used for generating the calibration curve are determined by taking the average or median value of the data of the plurality of differential pressures D1. Alternatively, the coordinates (V1 ', D1') for generating the calibration curve are determined by taking the average value or the median value of the data remaining after removing the data with low reliability from the data of the plurality of differential pressures D1.

Similarly, when there are a plurality of pieces of data of the differential pressure D0 when the resin pellet 9 of the type a is empty, for example, the control unit 90 statistically processes the pieces of data to calculate the coordinates (V0, D0). Specifically, the coordinates (V0 ', D0') used for generating the calibration curve are determined by taking the average or median value of the data of the plurality of differential pressures D0. Alternatively, the coordinates (V0 ', D0') for generating the calibration curve are determined by taking the average value or the median value of the data of the plurality of differential pressures D0, excluding the data with low reliability. In addition, the empty-bucket differential pressure D0 may be a method of statistically processing the measurement value, or may be a method of using the empty-bucket differential pressure D0 acquired in advance as a fixed set value.

Thereafter, the controller 90 generates the calibration curve L so that the calibration curve L passes through both the coordinates (V1 ', D1') and the coordinates (V0 ', D0') determined in the latest step. When the new data of the differential pressure D1(D0) is added to the memory 91, the controller 90 recalculates the coordinates (V1 ', D1') and the coordinates (V0 ', D0'), and updates the calibration curve L.

The control section 90 stores the latest calibration curve L in the memory 91 to be used in the subsequent processing of the resin pellets 9 of the type a.

The control unit 90 performs the same processing on the resin pellets 9 of the type B and the resin pellets 9 of the type C. In this way, the latest calibration curve L generated by category is stored in the memory 91.

<2-3. estimation of storage amount of powder/granule >

The control unit 90 of the present embodiment also estimates the storage amount S of the resin pellets 9 in the storage tank 10 by the same method as that described in embodiment 1. That is, the control unit 90 obtains the current estimated value of the storage amount based on the current differential pressure D between the front and rear sides of the storage tank 10 and the calibration curve L corresponding to the currently processed resin pellet 9 among the plurality of calibration curves L (S).

The control section 90 outputs an output signal corresponding to the estimated storage amount S. The output signal is input to, for example, a control panel of the powder/granular material processing apparatus 2, a display of a subsequent apparatus (in the present embodiment, a molding machine), a wireless communication terminal held by an operator, and the notification mechanism 97. Specifically, the notification means 97 may be a lighting lamp, a buzzer, or the like. The operator can change the level of the stored amount in the storage tank 10 when the alarm is issued by operating the input unit 93. Therefore, the operator can customize the alarm material level of the notification mechanism 97 according to the purpose, which is very convenient. Specifically, it is conceivable to set the alarm level to a lower limit value that affects the production efficiency if the stock amount is further reduced, for example.

Alternatively, the notification means 97 may be configured to issue an alarm in the following case. That is, the controller 90 may monitor the differential pressure D1 obtained when the hopper is full, and may output the differential pressure D1 to the notification mechanism 97 when the differential pressure D1 is largely different from the previous one even if the operator does not input a new "type" of the resin pellets 9 to the input unit 93. In other words, even if the non-input processing object is replaced with a different type of resin pellet 9, the notification means 97 may be configured to notify that the processing object is abnormal when the pressure loss at the full bucket largely fluctuates (to be equal to or more than the threshold value). In this way, if the characteristics of the pressure loss are different depending on the type of material, it is possible to find the misdischarge of the material by monitoring the differential pressure D1, which is advantageous.

In the present embodiment, the control unit 90 is configured to maintain the flow rate of the airflow flowing through the airflow circulation path 31 constant by performing feedback control on the drying blower 34 based on the output result of the air flow meter 80. This eliminates the fluctuation of the pressure loss due to the change in the flow rate of the gas, and accurately captures the correlation between the amount of resin pellets 9 retained in the retention tank 10 and the differential pressure across the retention tank 10 from the front to the rear by the calibration curve L.

As described above, in the powder/granular material processing method disclosed in the present embodiment, the storage amount S is estimated using any one of the plurality of calibration curves L corresponding to the plurality of types of resin pellets 9 having different properties. Thus, the amount of the resin pellets 9 stored in the storage tank 10 can be estimated using the calibration curve L appropriately selected according to the type of the resin pellets 9.

In the powder/granular material processing apparatus 2 disclosed in the present embodiment, the control unit (storage amount estimating means) 90 outputs an output signal corresponding to the estimated storage amount S. Thus, the operator can know the amount of the resin pellets 9 stored in the storage tank 10 based on the output signal. As a result, the operator can easily perform an appropriate operation according to the storage amount S of the resin pellets 9 in the storage tank 10.

In the powder/granular material processing apparatus 2 disclosed in the present embodiment, the memory 91 may store data on the calibration curve L for each type of resin pellet 9 having different properties. Thus, for example, the calibration curves L corresponding to the respective kinds of the resin particles 9 can be statistically corrected based on the data on the calibration curves L stored by the kinds.

In the powder/granular material processing apparatus 2 disclosed in the present embodiment, the control unit 90 maintains the flow rate of the airflow in the airflow circulation path 31 constant. This makes it possible to estimate the storage amount S of the resin pellets 9 in the storage tank 10 with high accuracy without being affected by the air volume of the air flowing through the airflow circulation path 31.

The powder/granular material processing apparatus 2 disclosed in the present embodiment further includes an alarm notification mechanism 97 that outputs an alarm in response to the output signal. Thus, the operator can recognize the amount S of the resin pellets 9 stored in the storage tank 10 by an alarm.

In the powder/granular material processing apparatus 2 disclosed in the present embodiment, the notification means 97 can change the level of the storage amount S when the alarm is issued. This can cause an alarm to be issued when the storage amount S of the resin pellets 9 in the storage tank 10 reaches an arbitrary level. Therefore, the alarm level of the powder/granular material processing apparatus 2 can be customized according to the purpose of the operator, and the apparatus is more user-friendly.

<3. Experimental example >

Next, an experiment for examining the correlation between the differential pressure before and after the storage tank and the volume (%) of the resin pellets stored in the storage tank and the results thereof will be described with reference to fig. 8. Fig. 8 is a graph showing a correlation between the differential pressure before and after the retention tank and the volume of the resin particles retained in the retention tank, which is obtained by the present experiment.

In this experiment, a powder and granular material processing apparatus having the same configuration as that shown in fig. 1 was used. As the resin particles, a white, flat polyethylene terephthalate resin having a bulk specific gravity of 0.85 was used. During this experiment, the flow rate of the airflow in the airflow circulation path was kept constant by performing feedback control while monitoring the detection result of the air gauge. In addition, the drying temperature was maintained at 80 ℃ during the experiment. A known volume of resin particles is intermittently replenished into the interior of the storage tank in an empty bucket state. After the resin pellets were replenished, the operation of checking the detection value of the differential pressure sensor was repeated after leaving for a predetermined time, and the checked value was recorded. Experiments of the same content were performed 2 times.

The x axis is the total volume of the resin pellets replenished into the storage tank, and the y axis is the differential pressure between before and after the storage tank, and the obtained experimental results are plotted as a graph, which is shown in fig. 8. An approximate straight line approximately plotted for each plotted point is shown in fig. 8. As is clear from fig. 8, the correlation between the volume of the resin particles in the storage tank and the differential pressure between the front and rear of the storage tank is expressed by a linear function. However, in a region where the volume of the resin particles in the storage tank is small, the separation distance between the plotted point obtained by the experiment and the approximate straight line is relatively wide. This is presumably because the storage level of the resin pellets in the storage tank becomes lower than the position of the outlet port of the airflow circulation path.

On the upper side of the 2 nd level gauge, the storage level of the resin pellets in the storage tank becomes higher than the position of the blow-out port, and therefore, it is considered that the deviation between the value on the approximate straight line and the actual value becomes smaller. In summary, it is considered that, when the storage level of the resin particles in the storage tank exceeds the lower limit level (the installation position of the 2 nd level gauge), the correlation between the volume of the resin particles in the storage tank and the differential pressure before and after the storage tank is grasped as a linear function.

<4. modified example >

The present invention is not limited to the above-described embodiments, but an exemplary embodiment of the present invention is described above.

In the above-described embodiment, the resin particles 9 are the powder or granular material to be processed, but the present invention is not necessarily limited thereto. That is, the "object to be processed" may be any powder or granule, and may be used as a raw material in various fields such as pharmaceuticals, chemicals, foods, and building materials instead of the resin particles 9.

In the above-described embodiment, the differential pressure detection means is the differential pressure sensor 40, but the present invention is not necessarily limited thereto. For example, a static pressure meter may be provided at each of the position P1 and the position P2, and the difference between the detection results may be used instead of the above-described method. Alternatively, a pressure gauge may be used as the differential pressure detection means.

The calibration curve L generated for each of the powdered or granular materials having different properties may be stored in advance, and when the powdered or granular material having a certain property is to be processed next time, the calibration curve L of another material having similar properties, which has been generated in the past, may be read and used.

The calibration curve L may be generated only when maintenance such as replacement of powder or granule in the powder or granule processing apparatus 1 or 2 is performed.

In embodiment 2, data (for example, values of the differential pressure D0 and D1) relating to the calibration curve L stored for each different characteristic may be deleted sequentially from the old data.

Instead of air, an inert gas such as nitrogen gas may be filled in the storage tank 10, the supply pipe 22, the gas flow circulation line 31, the measurement line 41, and the like.

Instead of the configuration of the material supply mechanism 20, the powder or granule (material) may be supplied to the storage tank 10 by another method. For example, the upper part of the storage tank 10 may be opened, and the powder or granule may be supplied from a supply mechanism in the upper part by gravity. Alternatively, the powder or granular material may be put into the storage tank 10 manually by an operator or by using an elevator or the like.

In the above embodiment, the conveyance blower 27 and the drying blower 34 are used as the pneumatic power generation source, but the manner of generating the air flow is not limited to this. For example, compressed air, a gas cylinder, or the like may be used to generate the air flow instead of the above.

In the above embodiment, the air gauge 80 may be omitted. In this case, the air volume may be determined based on the frequency during operation based on the characteristic value of the drying blower 34.

The airflow path does not necessarily have to be a circulation path for returning the airflow from the retention tank to the retention tank again. The storage groove is positioned in the middle of the airflow path.

The storage tank may be a simple storage container other than the drying hopper, and the inert gas or the dry air may be supplied as the gas flow through the gas flow path only when necessary. In such a case, the method for estimating the storage amount of the powder or granule disclosed in the present application can be applied.

In the above embodiment, the moisture adsorption unit 35 may be omitted.

Further, the details of the configuration, layout, and control method of each part may be different from those shown in the drawings of the present application. For example, the order of arrangement of the devices provided in the middle of the path of the airflow circulation path 31 may be different from the illustrated order.

Description of the reference numerals

1 powder treating apparatus

2 powder treating apparatus

9 resin particles

10 storage tank (air flow path)

11 side wall part

12 bottom

13 ceiling part

20 material supply mechanism

21 feeding hopper

22 supply pipe

23 supply valve

24 pot

25 throw-in mouth

27 conveying blower

30 airflow circulating mechanism

31 air circulation path (air path)

32 filter

33 cooler

34 drying blower

35 moisture adsorption unit

36 heater

40 differential pressure sensor

41 measuring pipeline

46 air outlet

51 st level indicator

52 nd 2 charge level indicator

70 temperature sensor

80 air gauge

90 control part

91 memory

93 input part

97 to the institution.

Claims

1. A method of processing a powder or granule by estimating the amount of the powder or granule stored in a storage tank in which the powder or granule to be processed is stored,

a) passing a gas flow through a gas flow path including the retention tank, thereby passing the gas flow through the powder;

b) detecting a differential pressure between a pressure in the airflow path on an upstream side of the storage tank and a pressure in the airflow path on a downstream side of the powder/granular material in the storage tank;

c) estimating the storage amount of the powder or granule in the storage tank based on the differential pressure detected in the step b).

2. The method for treating powder according to claim 1, wherein the powder is treated by the method,

in the a), dry air is passed through the air flow path as the air flow.

3. The method for treating powder according to claim 1 or 2,

in the step c), the storage amount of the powder and granular material in the storage tank is estimated based on a calibration curve showing a correlation between the differential pressure and the storage amount.

4. The method for treating powder according to claim 3, wherein the powder is treated by the method,

in the step c), the calibration curve is corrected based on a differential pressure detected when the storage amount of the powder/granular material in the storage tank is equal to or greater than a 1 st threshold value.

5. The method for treating powder according to claim 4, wherein the powder is treated by the method,

in the step c), the calibration curve is corrected based on a differential pressure detected when the amount of the powder or granule stored in the storage tank is less than a 2 nd threshold value that is smaller than the 1 st threshold value.

6. The method for treating powder according to any one of claims 3 to 5, wherein the powder is treated by the method,

in the step c), the calibration curve is corrected when the variation of the storage amount of the powder/granular material in the storage tank is smaller than a predetermined amount.

7. The method for treating powder according to any one of claims 1 to 6, wherein the powder is treated by the method,

d) after the c), displaying the information related to the storage amount estimated in the c) on a display unit.

8. The method for treating powder according to any one of claims 3 to 6, wherein the powder is treated by the method,

in the step c), the storage amount is estimated using any one of a plurality of calibration curves corresponding to a plurality of types of powder and granular bodies having different properties.

9. A powder/granular material processing apparatus is characterized by comprising:

a storage tank for storing therein a powder or granule as a treatment object;

an air flow path through which an air flow passes, the air flow path including the retention tank;

a differential pressure detection means for detecting a differential pressure between a pressure in the airflow path on an upstream side of the storage tank and a pressure in the airflow path on a downstream side of the powder/granular material in the storage tank;

and a storage amount estimating means for estimating the storage amount of the powder or granule in the storage tank based on the detection result of the differential pressure detecting means.

10. The powder treating apparatus according to claim 9, wherein the powder treating apparatus further comprises a mixer for mixing the powder with the granular material,

the storage amount estimating means outputs an output signal corresponding to the estimated storage amount.

11. The powder treating apparatus according to claim 9 or 10, wherein the powder treating apparatus further comprises a mixer for mixing the powder with the granular material,

the storage amount estimating means estimates the storage amount of the powder or granule in the storage tank based on a calibration curve showing a correlation between the differential pressure and the storage amount,

the powder processing device is provided with:

the storage device can store data relating to the calibration curve for each classification of powder and granular material having different properties for each classification.

12. The powder treating apparatus according to any one of claims 9 to 11, wherein the powder treating apparatus further comprises a mixer for mixing the powder with the powder,

the air volume adjusting mechanism is provided to maintain the flow volume of the air flow in the air flow path constant.

13. The powder treating apparatus according to claim 10, wherein the powder treating apparatus further comprises a mixer for mixing the powder with the powder,

and an alarm mechanism for giving an alarm according to the output signal.

14. The powder treating apparatus according to claim 13, wherein the powder treating apparatus further comprises a mixer for mixing the powder with the powder,

the notification mechanism can alter the reserve volume when an alarm is issued.