Material drying system

Abstract

A material drying system is provided with a material drying device, a material storage device, and an air blowing device, a material to be dried supplied from the material storage device to the material drying device is dried by a drying gas sent from the air blowing device to the material drying device, and the material drying system is also provided with a switching device for switching the material to be dried by the drying gas sent from the air blowing device to the material drying device. And a switching means for switching between feeding the exhaust gas discharged from the material drying means back to the air blowing means or introducing the exhaust gas into the material storage means. By the adoption of the material drying system, energy can be saved in a real sense.

Description

Technical Field

[0001] This invention relates to a material drying system. Background Technology

[0002] Previously known material drying systems dry powdered materials supplied to a destination such as a molding machine upstream of that destination. Such drying systems typically include a storage tank (material storage device) for storing the powdered material, and a hopper-shaped drying tank (material drying device) for storing and drying the powdered material supplied (replenished) from the storage tank. In these systems, the powdered material is dried in the drying tank using heated or dehumidified drying gas. The gas used to dry the powdered material in the drying tank is usually either directly discharged into the atmosphere or recycled back to the air supply device. Alternatively, to save energy, the gas used to dry the material in the drying tank is sent to a storage tank, where the residual heat of the dried gas is used to pre-dry the material in the storage tank (see Patent Document 1).

[0003] However, in the initial stage of the material drying system, the temperature of the material in the drying tank is low and the humidity is high. As a result, the gas after drying the material in the drying tank is also low in temperature and high in humidity. If it is sent back to the storage tank directly as in Patent Document 1, the material in the storage tank will absorb moisture instead, and the energy-saving effect will not be achieved.

[0004] Patent Document 1: CN111670330B Publication Summary of the Invention

[0005] The present invention addresses the aforementioned problems in the prior art, and its purpose is to provide a material drying system that can reliably achieve energy saving.

[0006] The first material drying system provided by the present invention includes a material drying device, a material storage device, and an air supply device. The material to be dried is supplied from the material storage device to the material drying device and dried using drying gas supplied from the air supply device to the material drying device. The system is characterized by having a switching device that switches between returning the exhaust gas discharged from the material drying device to the air supply device or introducing it into the material storage device.

[0007] The second material drying system provided by the present invention is based on the first material drying system, wherein the switching device switches the state from the exhaust gas discharged from the material drying device to the state of being introduced into the material storage device when the temperature of the exhaust gas reaches a predetermined value or above, or when at least one of the dew point and humidity of the exhaust gas reaches a predetermined value or below.

[0008] The third material drying system provided by the present invention is based on the first material drying system, wherein the switching device switches the exhaust gas discharged from the material drying device to the state of introducing it into the material storage device when a predetermined time has elapsed since the exhaust gas was discharged, or when a predetermined time has elapsed since the air supply device started supplying the drying gas.

[0009] The fourth material drying system provided by the present invention is based on any one of the first to third material drying systems, wherein the exhaust gas introduced into the material storage device is discharged from the material storage device to the outside or sent back to the air supply device.

[0010] The material drying system of this invention can truly achieve energy saving. Attached Figure Description

[0011] Figure 1 This is a schematic diagram illustrating one embodiment of the material drying system of the present invention.

[0012] Figure 2 This is a schematic diagram illustrating another embodiment of the material drying system of the present invention.

[0013] Explanation of reference numerals in the attached figures

[0014] 10: Material Drying System

[0015] 11: Material drying device

[0016] 12: Material storage device

[0017] 13: Air supply device

[0018] 18: Switching device

[0019] 19: Protective gas delivery device Detailed Implementation

[0020] Hereinafter, the preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0021] Figure 1 This is a schematic diagram illustrating one embodiment of the material drying system of the present invention.

[0022] like Figure 1 As shown, the material drying system 10 of the present invention includes a material drying device 11, a material storage device 12, and an air supply device 13. The powder material, which is the material to be dried, is supplied from the material storage device 12 to the material drying device 11 and is dried using drying gas (including recycled drying gas) supplied from the air supply device 13 to the material drying device 11.

[0023] Specifically, the material drying device 11 is connected to a molding machine (not shown) as the destination, and supplies the dried material to the molding machine. It is also connected to the air supply device 13 via a drying gas supply pipe 11a. In addition, a material supply pipe 14 connects the material drying device 11 and the material storage device 12.

[0024] The material storage device 12 is connected to a material supply source (not shown). The material supplied from the material supply source is first stored in the material storage device 12. At the initial stage of system operation, the material stored in the material storage device 12 is supplied to the material drying device 11 through the material supply pipeline 14. Then, after the material in the material drying device 11 is supplied to the molding machine, the material stored in the material storage device 12 is supplied to the material drying device 11 again through the material supply pipeline 14.

[0025] The air supply device 13, including a dehumidification section (not shown) and a blower, is a device for drying and dehumidifying air from the atmosphere or gas supplied from a circulating pipeline. The dried gas, after being dried and dehumidified in the air supply device 13, is sent to the material drying device 11 via a dry gas supply pipe 11a, where it is heated by a heater 11b installed on the dry gas supply pipe 11a. Furthermore, the air supply device 13 is connected to the exhaust port of the material storage device 12 via exhaust pipes 15a and 15b; the air inlet of the material storage device 12 is connected to the exhaust pipes 15a and 15b via dry gas supply and return pipes 16a and 16b. Simultaneously, the exhaust port of the material drying device 11 is connected to the dry gas supply and return pipes 16a and 16b via a dry gas reuse pipe 17.

[0026] The material drying system 10 of the present invention further includes a switching device 18, which is disposed at the connection between the drying gas supply and return pipes 16a and 16b and the drying gas reuse pipe 17. The function of the switching device 18 is to return the exhaust gas discharged from the material drying device 11 to the air supply device 13 or to the material storage device 12. Specifically, the switching device 18 may be, for example, a three-way switching valve disposed at the connection between the drying gas supply and return pipes 16a and 16b and the drying gas reuse pipe 17. That is, by switching the switching device 18, a portion of the exhaust gas discharged from the material drying device 11 can be sent to the material storage device 12 through the drying gas supply and return pipe 16a, or a portion of the exhaust gas discharged from the material drying device 11 can be sent back to the air supply device 13 through the drying gas supply and return pipe 16b and the exhaust pipe 15b. In this embodiment, the switching device 18 switches the exhaust gas discharged from the material drying device 11 to the material storage device 12 when the temperature of the exhaust gas discharged from the material drying device 11 reaches a predetermined value or above, or when at least one of the dew point or humidity of the exhaust gas reaches a predetermined value or below. Conversely, the switching device 18 switches the exhaust gas discharged from the material drying device 11 to (or maintains) the state of returning it to the air supply device 13 when the temperature of the exhaust gas discharged from the material drying device 11 is lower than a predetermined value, or when at least one of the dew point or humidity of the exhaust gas is higher than a predetermined value. The specified temperature value is set as follows: From a practical perspective, it is set within the range of +2°C to +20°C based on the outside air temperature. However, due to seasonal variations in outside air temperature, or differences in the materials being dried, the hygroscopicity of the materials to be dried will also change. Therefore, the specified temperature value can be set according to the season or the materials used. For example, in winter, the ambient temperature is low, the hygroscopicity of the materials being dried is low, or the materials themselves have low hygroscopicity; therefore, the specified temperature value can be set lower. On the other hand, the specified dew point value is set as follows: From a practical perspective, it is set within the range of -2dp°C to -20dp°C based on the outside air dew point. However, due to seasonal variations in outside air dew point, or differences in the materials being dried, the hygroscopicity of the materials to be dried will also change. Therefore, the specified dew point value can be set according to the season or the materials used. For example, in winter, the ambient temperature is low, the hygroscopicity of the materials being dried is low, or the materials themselves have low hygroscopicity; therefore, the specified dew point value can be set slightly higher.Similarly, the specified humidity value is set as follows: from a practical point of view, it is set within the range of -2% to -20% of the external air humidity. However, due to different seasons, the external air humidity varies, or the materials used for drying are different, and the hygroscopicity of the materials to be dried will also change. Therefore, the specified humidity value can be set according to the season or the materials used. For example, in winter, the ambient temperature is low, the hygroscopicity of the materials to be dried is low, or the materials used themselves have low hygroscopicity. Therefore, the specified humidity value can be set slightly higher.

[0027] The temperature, dew point, and humidity of the exhaust gas, as well as the temperature, dew point, and humidity of the outside air, are detected by devices such as sensors or detectors installed in different locations (not shown). The control device of the material drying system 10 of the present invention compares the detected temperature, dew point, and humidity of the exhaust gas and the outside air with pre-set predetermined values, and controls the switching device 18 to switch based on the comparison results. This ensures that when the temperature of the exhaust gas is lower than the predetermined value (or the dew point or humidity of the exhaust gas is higher than the predetermined value) (e.g., at the initial start-up of the material drying system 10), the switching device 18 is switched to (or maintained at) a state where the exhaust gas is returned to the air supply device 13, preventing the low-temperature, humid exhaust gas from being sent to the material storage device 12 and causing the materials in the material storage device 12 to absorb moisture. On the other hand, it also ensures that when the temperature of the exhaust gas reaches a specified value or above (or the dew point or humidity of the exhaust gas reaches a specified value or below) (for example, after the material drying system 10 has been running for a period of time), the switching device 18 is switched to the state of introducing the exhaust gas into the material storage device 12, so that the dried exhaust gas preheats and dries the material stored in the material storage device 12, thereby achieving the purpose of energy saving.

[0028] Furthermore, the exhaust gas returned to the air supply device 13 is reheated and dried by the air supply device 13 before being sent to the material drying device 11. The requirements and settings for the temperature, dew point, and humidity of the drying gas sent from the air supply device 13 to the material drying device 11 are the same as in the prior art, and detailed descriptions are omitted here. Similarly, the control device and control method of the material drying system 10 of the present invention also employ conventional devices and methods, and detailed descriptions are also omitted here. At the same time, the various valves (opening and closing valves, check valves, etc.), switches, and dust removal equipment installed in the system also employ conventional settings in the art, and detailed descriptions are also omitted here.

[0029] Therefore, by employing the material drying system 10 of the present invention, the exhaust gas from the material drying device 11 can be selectively introduced into the material storage device 12 or sent back to the air supply device 13. This achieves greater energy savings compared to not introducing the exhaust gas from the material drying device 11 into the material storage device 12, or introducing the exhaust gas from the material drying device 11 into the material storage device 12 when the temperature is low and the dew point humidity is still high at the initial stage of system startup.

[0030] Furthermore, the material drying system 10 of the present invention can also be modified to... Figure 2 The illustrated embodiment. (Compared to...) Figure 1 Compared to the illustrated embodiment, the modified embodiment adds a protective gas delivery device 19 for supplying protective gas (e.g., nitrogen) and protective gas delivery pipes 19a, 19b, and 19c for delivering the protective gas from the protective gas delivery device 19 to the material drying device 11 and the material storage device 12, respectively. Figure 2 As shown, the portion of the protective gas delivery pipe 19b that delivers the protective gas to the material storage device 12 is directly connected to the protective gas inlet on the material storage device 12; while the portion of the protective gas delivery pipe 19c that delivers the protective gas to the material drying device 11 is connected to the drying gas supply pipe 11a. That is, the protective gas is delivered to the material drying device 11 along with the drying gas via the protective gas delivery pipe 19a, the protective gas delivery pipe 19c, and the drying gas supply pipe 11a. Alternatively, the protective gas delivery pipe 19c can be directly connected to the protective gas inlet of the material drying device 11, meaning the protective gas is directly delivered from the protective gas delivery device 19 to the material drying device 11 via the protective gas delivery pipes 19a and 19c. Therefore, with... Figure 1 Compared to the embodiments shown, Figure 2 The illustrated embodiment also prevents oxidation or yellowing of the material, thus ensuring material quality. Regarding the protective gas delivery device 19, a conventional device in the art is used, and a detailed description of its structure is omitted here. Furthermore, the structure, connection method, and various valves (opening / closing valves, check valves, etc.), switches, etc., installed on the protective gas delivery pipes 19a, 19b, and 19c are also conventional in the art, and their detailed descriptions are also omitted here.

[0031] The following modifications can also be made to the above embodiments of the present invention.

[0032] The switching device 18 is configured to switch the exhaust gas discharged from the material drying device 11 to the state of being introduced into the material storage device 12 when a predetermined elapsed time has elapsed since the exhaust gas began to be discharged, or when a predetermined elapsed time has elapsed since the air supply device 13 began to supply the drying gas. Specifically, the control system of the material drying system 10 of the present invention starts timing from the time the exhaust gas begins to be discharged from the material drying device 11 after the system starts. When a predetermined elapsed time has elapsed since the exhaust gas begins to be discharged from the material drying device 11, the switching device 18 is used to switch the exhaust gas discharged from the material drying device 11 to the state of being introduced into the material storage device 12. Conversely, if the predetermined elapsed time has not elapsed since the exhaust gas begins to be discharged from the material drying device 11 after the system starts, the switching device 18 will switch the exhaust gas discharged from the material drying device 11 to (or maintain) the state of being returned to the air supply device 13. Alternatively, the switching device 18 can be modified to switch the exhaust gas discharged from the material drying device 11 to the state of introducing it into the material storage device 12 after a predetermined elapsed time has elapsed since the drying gas was first supplied from the air supply device 13. Specifically, the control system of the material drying system 10 of the present invention starts timing from the time the drying gas is first supplied from the air supply device 13 after the system starts. When a predetermined elapsed time has elapsed since the air supply device 13 starts supplying air, the switching device 18 switches the exhaust gas discharged from the material drying device 11 to the state of introducing it into the material storage device 12. Conversely, if the predetermined elapsed time has not elapsed since the air supply device 13 starts supplying air after the system starts, the switching device 18 switches the exhaust gas discharged from the material drying device 11 to (or maintains) the state of returning the exhaust gas to the air supply device 13. Furthermore, from a practical standpoint, the specified time intervals mentioned above can be set between 60 and 120 minutes. However, due to seasonal variations in external air temperature and the hygroscopicity of the materials being dried, the specified time intervals can be adjusted according to the season, such as in winter.

[0033] When the ambient temperature is low, the material being dried has low hygroscopicity; therefore, the specified time can be set to be shorter.

[0034] In addition, the exhaust gas introduced into the material storage device 12 can also be discharged directly from the material storage device 12 to the outside without being sent back to the air supply device 13.

[0035] In addition, the material drying system 10 of the present invention can also be applied to the drying of materials other than powder materials.

Claims

1. A material drying system comprising a material drying device, a material storage device, and an air supply device, wherein the material to be dried supplied from the material storage device to the material drying device is dried using a drying gas supplied from the air supply device to the material drying device, characterized in that, It has a switching device that switches between returning the exhaust gas discharged from the material drying device to the air supply device or introducing it into the material storage device.

2. The material drying system as described in claim 1, characterized in that, The switching device switches the exhaust gas discharged from the material drying device to the material storage device when the temperature of the exhaust gas reaches a specified value or above, or when at least one of the dew point or humidity of the exhaust gas reaches a specified value or below.

3. The material drying system as described in claim 1, characterized in that, The switching device switches the exhaust gas discharged from the material drying device to the state of introducing it into the material storage device when a predetermined time has elapsed since the exhaust gas was discharged, or when a predetermined time has elapsed since the air supply device started supplying the drying gas.

4. The material drying system according to any one of claims 1 to 3, characterized in that, The exhaust gas introduced into the material storage device is either discharged from the material storage device to the outside or returned to the air supply device.

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