JP5753458B2 - Drying equipment - Google Patents

Description

  The present invention relates to a drying apparatus that supplies a drying medium into a drying container to dry a granular material in the drying container.

  2. Description of the Related Art Conventionally, a drying apparatus has been used to dry powder particles such as resin pellets that are resin molding materials. For example, the drying apparatus disclosed in Patent Document 1 sucks the inside of a temporary storage container, a drying container, a blowing unit that supplies dry air to the drying container, a temporary storage container that temporarily stores the material supplied to the drying container, and the like. And a suction means for pneumatically transporting the material to the temporary storage container. The temporary storage container has an opening / closing valve at a material supply port communicating with the drying container. This on-off valve is opened by the weight of the material of the temporary storage container and the weight of the on-off valve.

  In addition, when the inside of the drying container becomes higher than the atmospheric pressure by the dry air supplied to the drying container, the opening / closing valve does not open even if the material is stored in the temporary storage container. In addition, in the drying apparatus of Patent Document 1, the suction means is a means for sucking the temporary storage container and transporting the material, and also serves as a means for decompressing the drying container. Specifically, a three-way valve is provided in the middle of a pipe connecting the suction means and the temporary storage container, and a branch pipe reaching the drying container is connected to the three-way valve. Then, after the inside of the temporary storage container is sucked by the suction means and the material is transported for a predetermined time, when the inside of the drying container is higher than the atmospheric pressure, the three-way valve is brought into a state where the drying container and the suction means communicate with each other. By switching, the inside of the drying container is sucked by the suction means to reduce the pressure.

JP 2010-260185 A

  However, in the drying device of Patent Document 1, after the material is transported to the temporary storage container by the suction means, when the inside of the drying container is higher than the atmospheric pressure, suction is performed only to depressurize the inside of the drying container. Driving means. That is, energy for driving the suction means is required only for decompressing the drying container.

  Then, an object of this invention is to provide the drying apparatus which does not require energy only in order to decompress the drying container.

Means for Solving the Problems and Effects of the Invention

A drying apparatus according to a first aspect of the present invention includes a drying container, a temporary storage container that communicates with the drying container via a material supply port provided with an on-off valve, and temporarily stores the material supplied to the drying container. A blowing means for blowing out the drying medium, a drying medium supply channel connected to the blowing means and the drying container for supplying the drying medium blown from the blowing means to the drying container, and the drying medium supply flow A bypass passage connected to a passage for supplying the drying medium in the drying medium supply passage to the blowing means, and at least a part of the drying medium in the drying medium supply passage passes through the bypass passage. Then, switching means capable of switching between a communication state supplied to the blower means and a shut-off state blocking the bypass flow path , and sucking the inside of the temporary storage container to pneumatically transport the material to the temporary storage container Suction hand With the door, said switching means, wherein said a cut-off state, automatically be switched from the disconnected state to the communicating state when said suction means is stopped when said suction means is driven And

According to this configuration, when the suction unit is driven and the material is being transported to the temporary storage container, the switching unit is in the shut-off state, and thus all the drying medium blown from the blowing unit is supplied to the drying container. Therefore, the drying medium can be sufficiently supplied to the drying container. When the suction means is stopped and the transportation of the material to the temporary storage container is stopped, the switching means is automatically switched from the shut-off state to the communication state. When all of the drying medium blown from the blowing means is supplied to the drying container by setting the switching means in a communicating state and returning at least a part of the drying medium blown from the blowing means to the blowing means through the bypass channel As compared with the above, the pressure in the drying container can be lowered. Therefore, the on-off valve can be opened by the weight of the material of the temporary storage container (and the weight of the on-off valve), and the material of the temporary storage container can be reliably supplied to the drying container.
Further, when the pressure is reduced by sucking the inside of the drying container, the energy for driving the suction means is required only for reducing the pressure of the drying container. In the present invention, the flow of the drying medium sent from the blowing means Since the inside of the drying container is decompressed by changing, the inside of the drying container can be decompressed without requiring new energy just to decompress the drying container.

In the drying apparatus according to a second aspect of the present invention, in the first aspect, a heater for heating the drying medium is provided in the drying medium supply flow path, and the bypass flow path stores the drying medium that has passed through the heater. It supplies to the said ventilation means, It is characterized by the above-mentioned.

When the bypass passage is configured to supply the drying medium before passing through the heater to the blowing means, the amount of air passing through the heater when the switching means is in communication is greater than when the switching means is in the shut-off state. Less. Therefore, when the switching means is in the communication state, the load applied to the heat source of the heater is large, and the life of the heat source is shortened. Further, when the switching means is switched, the air volume of the drying medium passing through the heater changes, so that it is difficult to heat the drying medium to the target temperature, and the temperature of the drying medium that has passed through the heater fluctuates.
On the other hand, in the present invention, since the bypass flow path is configured to supply the drying medium that has passed through the heater to the blowing means, the air volume passing through the heater is constant. Therefore, it is possible to prevent an increase in load on the heat source of the heater and to prevent fluctuations in the temperature of the drying medium.
Note that “the bypass flow path supplies the drying medium that has passed through the heater to the blowing means” means that the bypass flow path is connected to the outlet of the heater and the downstream side of the heater of the dry medium supply flow path. Including when connected.

Drying apparatus for drying the third invention, in the second invention, on the downstream side of the heater in the drying medium supply passage, and a temperature sensor is provided, the bypass flow path, passing through the temperature sensor A medium is supplied to the blowing means.

Since the heat of the drying medium in the pipe is radiated through the pipe, the temperature in the pipe is lower on the inner peripheral surface side than on the center side, and this temperature gradient increases as the amount of air passing through the pipe decreases.
When the bypass channel is configured to supply the drying medium before passing through the temperature sensor to the blowing unit, the drying medium after passing through the temperature sensor is supplied to the blowing unit as in the present invention. Compared to the case where it is configured, the amount of air passing through the temperature sensor is reduced when the switching means is in the communication state. Therefore, in order to accurately measure the temperature of the drying medium in the pipe, a temperature sensor must be arranged so that the temperature at the pipe center can be detected, and positioning is difficult.
On the other hand, in the present invention, the bypass flow path is configured to supply the drying medium that has passed through the temperature sensor to the air blowing means, and since the amount of air passing through the pipe provided with the temperature sensor is large, the temperature in the pipe The gradient becomes smaller. For this reason, the range in which the temperature can be accurately detected is widened, and the temperature sensor can be easily positioned.

It is a circuit diagram of the drying device concerning the embodiment of the present invention, and is a figure showing the state where materials are being transported to the loader hopper. It is a circuit diagram of the drying device concerning an embodiment of the present invention, and is a figure showing the state where material is supplied to a drying container. It is a flowchart which shows operation | movement of a drying apparatus. It is a figure which shows a part of drying apparatus which concerns on other embodiment of this invention.

Embodiments of the present invention will be described below.
The drying apparatus 1 according to the present embodiment is an apparatus for drying a granular material such as a resin pellet. As shown in FIG. 1, a drying apparatus 1 includes a drying hopper (drying container) 20, a drying blower (blower unit) 21, a heater 22, a temperature sensor 23, a switching valve (switching unit) 24, and a dry air filter. 25, etc., a drying line 2, a loader hopper (temporary storage container) 30, a material tank 31, a transport blower (suction means) 32, and a filter 33 that temporarily store the material supplied to the drying hopper 20. Is constituted by a transport line 3 connected to the control line (not shown).

  The transport line 3 is a line for transporting the material stored in the material tank 31 to the loader hopper 30. The transport line 3 connects the material tank 31 and the loader hopper 30, the transport blower 32, and the loader. A suction flow path 3b connecting the hopper 30;

  The loader hopper 30 is a cylindrical container having a tapered lower portion. The material transport channel 3 a and the suction channel 3 b are connected to the upper wall of the loader hopper 30. The loader hopper 30 is disposed on the upper side of the drying hopper 20, and the lower portion of the loader hopper 30 penetrates the upper wall of the drying hopper 20 and is disposed in the drying hopper 20. A material supply port 30 a is formed at the lower end of the loader hopper 30 located in the drying hopper 20. An open / close valve 34 is provided in the material supply port 30a.

  The on-off valve 34 is made of a metal plate bent in a V shape, and is suspended from the ceiling surface of the drying hopper 20 so as to swing around the bent portion. In a state where the operation of the drying device 1 is not performed, the on-off valve 34 is separated from the material supply port 30a as indicated by a broken line in FIG. When the internal pressure of the loader hopper 30 becomes lower than the internal pressure on the drying hopper 20 side by a predetermined value or more, the open / close valve 34 is drawn toward the material supply port 30a as shown by the solid line in FIG. 2 to close the material supply port 30a.

  The transport blower 32 is provided for sucking the loader hopper 30 through the suction flow path 3b. By sucking the loader hopper 30, the material in the material tank 31 is pneumatically transported to the loader hopper 30 via the material transport channel 3a.

  A filter 33 is provided in the suction channel 3b. The filter 33 is provided to capture dust and material mixed in the air passing through the suction flow path 3b.

  The drying line 2 includes a drying air supply channel (drying medium supply channel) 2 a that connects the drying hopper 20 and the blower outlet of the drying blower 21, and a drying air that connects the drying hopper 20 and the suction port of the drying blower 21. The return flow path 2b has a bypass flow path 2c that connects the middle of the dry air supply flow path 2a and the middle of the dry air return flow path 2b. In the drying line 2, drying air (drying medium) for drying the material in the drying hopper 20 flows.

  The drying hopper 20 is a cylindrical container having a tapered lower portion. A material discharge port 20 a is formed at the lower end of the drying hopper 20. A dry air supply channel 2 a and a dry air return channel 2 b are connected to the side wall of the drying hopper 20. The tip of the dry air supply channel 2 a is disposed in the dry hopper 20. The tip of the dry air supply channel 2a opens downward, and is formed so that the diameter increases toward the lower side. In FIG. 1, the dry air supply flow path 2 a passes through the side wall of the dry hopper 20, but may pass through the lid of the dry hopper 20. In addition, a level meter (not shown) for detecting the amount of material in the dry hopper 20 is provided in the upper part of the dry hopper 20.

  The dry air supply flow path 2 a is a flow path for supplying the dry air blown from the dry blower 21 to the dry hopper 20. The air volume blown from the dry blower 21 is constant.

  The dry air supply channel 2a is provided with a heater 22 for heating the dry air to a target temperature. A temperature sensor 23 is provided at a position downstream of the heater 22 in the dry air supply flow path 2a. The heater 22 performs temperature adjustment by alternately repeating the on state and the off state according to the temperature difference between the temperature detected by the temperature sensor 23 and the target temperature. The heater 22 has two air outlets, and a bypass channel 2c is connected to one of the outlets.

  The dry air return flow path 2 b is a flow path for discharging the dry air in the dry hopper 20 from the dry hopper 20 and supplying it to the dry blower 21. A dry air filter 25, a discharge pipe 26, and an air intake pipe 27 are provided in this order from the dry hopper 20 side in the dry air return flow path 2b. An atmospheric filter 28 is provided in the atmospheric intake pipe 27. After the dust is removed by the dry air filter 25, a part of the dry air discharged from the drying hopper 20 is discharged to the atmosphere through the discharge pipe 26. Further, the air flowing into the air intake pipe 27 is mixed with dry air flowing through the dry air return flow path 2b after dust is removed by the air filter 28.

  The bypass flow path 2 c is a flow path for supplying the dry air in the dry air supply flow path 2 a to the dry blower 21. In the present embodiment, the bypass flow path 2c has one end connected to the outlet of the heater 22 and the other end connected to a portion between the discharge pipe 26 and the atmospheric intake pipe 27 of the dry air return flow path 2b. Yes. Therefore, the bypass flow path 2 c supplies the dry air that has passed through the heater 22 to the dry blower 21.

  A switching valve 24 is provided in the bypass flow path 2c. The switching valve 24 is an electromagnetic valve, and when not energized, the bypass valve 2c is shut off as shown in FIG. 1 (blocked state). When energized, the bypass valve 2c is communicated as shown in FIG. Switch to state. In the communication state, a part of the dry air in the dry air supply flow path 2a is supplied to the dry blower 21 through the bypass flow path 2c.

  Next, operation | movement of the drying apparatus 1 is demonstrated using the flowchart of FIG.

  First, driving of the heater 22 and the drying blower 21 is started (step S1). At this time, the on-off valve 34 is in an open state indicated by a broken line in FIG. 1, and the switching valve 24 is in a non-energized state shown in FIG. Therefore, all the dry air blown out from the dry blower 21 and heated by the heater 22 is supplied to the dry hopper 20. Further, the dry air in the dry hopper 20 is discharged and sucked through the dry air return flow path 2b. The pressure balance of the dry air to the drying hopper 20 is a positive pressure.

  Next, when it is detected by a level meter (not shown) in the dry hopper 20 that the material in the dry hopper 20 is less than a predetermined amount (including the case of no material) (step S2, Yse), the transport blower 32 is started (step S3). The inside of the loader hopper 30 is sucked into the negative pressure by the transport blower 32, whereby the on-off valve 34 is drawn toward the material supply port 30a and closes the material supply port 30a. When the loader hopper 30 is further sucked, the material in the material tank 31 is pneumatically transported to the loader hopper 30.

  The material is transported by continuing to drive the transport blower 32 until a predetermined time elapses after the drive of the transport blower 32 is started (step S4, No). Although the weight of the material applied to the opening / closing valve 34 gradually increases, the suction force of the transport blower 32 is superior and the opening / closing valve 34 does not open.

  Then, when a predetermined time has elapsed from the start of driving (step S4, Yes), the transport blower 32 is stopped to stop the transport of the material (step S5). When the transport blower 32 is stopped, the switching valve 24 is automatically energized to switch the switching valve 24 from the shut-off state to the communication state (step S6). Thereby, a part of the dry air blown out from the dry blower 21 and heated by the heater 22 is returned to the dry blower 21 through the bypass channel 2 c, and the rest is supplied to the dry hopper 20. Therefore, the pressure in the drying hopper 20 decreases. As a result, the opening / closing valve 34 is opened by the weight of the material and the weight of the opening / closing valve 34, and the material in the loader hopper 30 is supplied to the drying hopper 20. And the material supplied in the drying hopper 20 is dried with dry air.

  From the start of energization to the switching valve 24 (after switching to the communication state), until the predetermined time elapses (No in step S7), the switching valve 24 is maintained in the communication state, and the material in the loader hopper 30 is removed. All supplied to the drying hopper 20. When a predetermined time has elapsed from the start of energization to the switching valve 24 (step S7, Yes), the energization to the switching valve 24 is stopped and the switching valve 24 is switched from the communication state to the shut-off state (step S8).

  Next, when it is detected by a level meter (not shown) in the drying hopper 20 that the material in the drying hopper 20 is less than a predetermined amount (No in step S9), step S3 to step S8 until the predetermined amount is reached. repeat. After the material in the drying hopper 20 reaches a predetermined amount, if the material is discharged and falls below the predetermined amount (No at Step S9), Step S3 and subsequent steps are performed again.

According to the drying apparatus 1 of the present embodiment, the switching valve 24 is brought into a communication state, and at least a part of the dry air blown from the drying blower 21 is returned to the drying blower 21 via the bypass flow path 2c, whereby the drying blower Compared with the case where all the dry air blown out from 21 is supplied to the drying hopper 20, the pressure in the drying hopper 20 can be lowered. Therefore, the opening / closing valve 34 can be opened by the weight of the material of the loader hopper 30 and the weight of the opening / closing valve 34, and the material of the loader hopper 30 can be reliably supplied to the drying hopper 20.
Further, when the pressure is reduced by sucking the inside of the drying hopper 20, energy for driving the suction means is required only for reducing the pressure of the drying hopper 20. In this embodiment, the energy is sent from the drying blower 21. Since the inside of the drying hopper 20 is decompressed by changing the flow of the drying air, the inside of the drying hopper 20 can be decompressed without requiring new energy only for decompressing the drying hopper 20.

  Further, in the present embodiment, when the transport blower 32 is driven and the material is transported to the loader hopper 30, the switching valve 24 is in the shut-off state, so that all the dry air blown from the dry blower 21 is the dry hopper. 20 is supplied. Therefore, the dry air can be sufficiently supplied to the dry hopper 20.

  Moreover, in this embodiment, when the transport blower 32 is stopped and the transport of the material to the loader hopper 30 is stopped, the switching valve 24 is automatically switched from the shut-off state to the communication state. As a result, the drying hopper 20 is depressurized, the on-off valve 34 is opened, and the material in the loader hopper 30 is supplied to the drying hopper 20. Therefore, the supply of the material to the drying hopper 20 can be smoothly started after the transportation of the material to the loader hopper 30 is stopped.

When the bypass flow path is configured to supply the dry air before passing through the heater to the dry blower, the amount of air passing through the heater when the switching valve is in communication is when the switching valve is in the shut-off state. Less than the amount of air passing through the heater. For this reason, when the switching valve is in communication, the load applied to the heat source of the heater is large, and the life of the heat source is shortened. Further, when the switching valve is switched, the air volume of the dry air that passes through the heater changes, so that it is difficult to adjust the temperature of the dry air to the target temperature, and the temperature of the dry air that has passed through the heater fluctuates.
On the other hand, in this embodiment, since the bypass flow path 2c is configured to supply the dry air that has passed through the heater 22 to the dry blower 21, the amount of air passing through the heater 22 is constant. Therefore, an increase in load applied to the heat source of the heater 22 can be prevented, and fluctuations in the temperature of the dry air that has passed through the heater 22 can be prevented.

  The preferred embodiment of the present invention has been described above, but the above embodiment can be modified as follows. In addition, about the thing which has the structure similar to the said embodiment, the description is abbreviate | omitted suitably using the same code | symbol.

  In the above embodiment, the switching valve 24 is automatically switched from the shut-off state to the communication state when the transport blower 32 is stopped. The timing for switching the switching valve 24 from the shut-off state to the communication state is as follows. It is not limited to this. For example, a pressure sensor for detecting the pressure in the drying hopper 20 is installed, and after step S5, the switching valve 24 is switched from the shut-off state to the communication state only when the pressure in the drying hopper 20 is equal to or higher than a predetermined value. It may be.

In the above embodiment, the upstream end of the bypass flow path 2c is connected to one of the two outlets of the heater 22 of the dry air supply flow path 2a, but is not limited to this configuration.
For example, a bypass channel may be connected upstream of the heater 22 of the dry air supply channel 2a.
Further, for example, a bypass channel may be connected to the downstream side of the heater 22 of the dry air supply channel 2a. In this case, since the amount of air passing through the heater 22 is constant as in the above embodiment, an increase in the load applied to the heat source of the heater 22 can be prevented and fluctuations in the temperature of the dry air can be prevented.

Further, when the bypass flow path is connected to the downstream side of the heater 22 of the dry air supply flow path 2a, the bypass flow path may be connected between the temperature sensor 23 and the heater 22, and further to the downstream side of the temperature sensor 23. A bypass channel may be connected. However, in the following points, it is preferable to connect a bypass flow path downstream from the temperature sensor 23.
Since the heat of the dry air in the pipe is radiated through the pipe, the temperature in the pipe is lower on the inner peripheral surface side than on the center side, and this temperature gradient increases as the amount of air passing through the pipe decreases. When the bypass flow path is connected between the temperature sensor 23 and the heater 22, the temperature sensor 23 is turned on when the switching valve 24 is in a communication state as compared with the case where the bypass flow path is connected downstream of the temperature sensor 23. The amount of air passing through decreases. Therefore, in order to accurately measure the temperature of the dry air in the pipe, the temperature sensor 23 must be arranged so that the temperature at the pipe center can be detected, and positioning is difficult. On the other hand, when the bypass flow path is connected to the downstream side of the temperature sensor 23, since the air volume passing through the pipe provided with the temperature sensor 23 is large, the temperature gradient in the pipe becomes small. For this reason, the range in which the temperature can be detected with high accuracy is widened, and positioning of the temperature sensor 23 is facilitated.

  Moreover, in the said embodiment, although the downstream end of the bypass flow path 2c is connected between the discharge pipe 26 and the atmospheric | air intake pipe | tube 27 of the dry air return flow path 2b, it is not limited to this structure. The downstream end of the bypass flow path 2c may be connected to a portion other than the above of the dry air return flow path 2b, or may be connected to the suction port of the dry blower 21.

  In the above embodiment, the switching valve 24 is disposed in the middle of the bypass flow path 2c, but may be disposed at a connection portion between the bypass flow path 2c and the dry air supply flow path 2a. You may arrange | position in the connection part with the dry air return flow path 2b.

  Moreover, in the said embodiment, when the switching valve 24 is a communication state, it is comprised so that a part of dry air in the dry air supply flow path 2a may pass the bypass flow path 2c, but a switching means is a communication state. In this case, all of the dry air in the dry air supply flow path 2a may pass through the bypass flow path 2c. Specifically, for example, as shown in FIG. 4, the switching valve 124 is a three-way valve provided at a connection portion between the bypass flow path 102 c and the dry air supply flow path 102 a, and is blown out from the dry blower 21. It may be possible to switch between a communication state in which all the dry air passes through the bypass channel 102c and a blocking state in which the bypass channel 102c is blocked. In this case, the temperature sensor 23 is provided between the switching valve 124 of the dry air supply flow path 102 a and the heater 22.

  The switching valve 24 is not limited to a solenoid valve. For example, a valve that can be manually switched between a communication state and a cutoff state may be used.

  The on-off valve 34 is not limited to the configuration of the above-described embodiment as long as it opens and closes according to the pressure difference between the loader hopper 30 and the drying hopper 20.

  In the above embodiment, the material is pneumatically transported into the loader hopper 30 by suctioning the loader hopper 30 with the transport blower 32, but the configuration for supplying the material to the loader hopper 30 is not limited to this. For example, the material may be manually supplied to the loader hopper 30.

DESCRIPTION OF SYMBOLS 1 Drying apparatus 2a, 102a Dry air supply flow path (Dry medium supply flow path)
2c, 102c Bypass channel 20 Drying hopper (drying container)
21 Drying blower (air blowing means)
22 Heater 23 Temperature sensor 24, 124 Switching valve (switching means)
30 Loader hopper (temporary storage container)
30a Material supply port 32 Transport blower (suction means)
34 On-off valve

Claims (3)

A drying container;
A temporary storage container that communicates with the drying container via a material supply port provided with an on-off valve, and temporarily stores the material supplied to the drying container;
A blowing means for blowing out the drying medium;
A drying medium supply channel connected to the blowing means and the drying container for supplying the drying medium blown from the blowing means to the drying container;
A bypass flow path connected to the dry medium supply flow path for supplying the dry medium in the dry medium supply flow path to the blowing means;
Switching means capable of switching between a communication state in which at least a part of the drying medium in the drying medium supply flow path passes through the bypass flow path and is supplied to the blower means, and a shut-off state that blocks the bypass flow path and,
A suction means for sucking the inside of the temporary storage container and pneumatically transporting the material to the temporary storage container ;
The switching means is in the shut-off state when the suction means is driven, and is automatically switched from the shut-off state to the communication state when the suction means stops. . A heater for heating the drying medium is provided in the drying medium supply channel,
The drying apparatus according to claim 1, wherein the bypass passage supplies the drying medium that has passed through the heater to the blowing unit. A temperature sensor is provided downstream of the heater in the drying medium supply channel,
The drying apparatus according to claim 2 , wherein the bypass passage supplies the drying medium that has passed through the temperature sensor to the blowing unit.

Images