JPH0429954B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat exchange device incorporating a fluidized bed heat exchanger.

Conventional structure and its problems A heat exchange device incorporating a fluidized bed heat exchanger in which solid particles floating and flowing due to the airflow generated by a blower collide with heat transfer tubes and exchange heat with the airflow outside the tubes and the fluid inside the tubes. has the advantage that when the floating solid particles collide with the heat transfer tube, the temperature boundary layer is destroyed and the heat transfer coefficient is significantly improved.
Future development is expected.

However, in such a heat exchange device, when a low-temperature fluid is passed through the heat exchanger tubes to exchange heat with an air flow outside the tubes, when the temperature of the heat exchanger tubes becomes lower than the dew point temperature of the surrounding air, dew condensation occurs on the surfaces of the heat exchanger tubes. Therefore, when floating and flowing solid particles collide with the heat transfer tube, moisture adheres to the solid particles. When moisture adheres, the fluidity of solid particles gradually decreases. Therefore, when the blower is stopped and then restarted, the fluidization state is very poor, and the high heat transfer coefficient, which is a characteristic of the fluidized bed heat exchanger, cannot be fully utilized.

OBJECTS OF THE INVENTION An object of the present invention is to eliminate the above-mentioned conventional drawbacks and provide a heat exchange device that takes advantage of the high heat transfer coefficient that is a feature of a fluidized bed heat exchanger.

Structure of the Invention The present invention provides a fluidized bed heat exchanger comprising a plurality of heat exchanger tubes and solid particles floating and flowing around the outer periphery of the plurality of heat exchanger tubes, and an absolute flow rate of air at the inlet and outlet of the fluidized bed heat exchanger. The above object is achieved by a device that is composed of a detector that detects humidity changes, a blower that generates an airflow that passes through the fluidized bed heat exchanger, and a control device that uses the detector to stop the blower. This is what I did.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the heat exchange device of the present invention is shown in FIG. In FIG. 1, a blower 3 and a motor 4 for the blower 3 are located above a plurality of heat exchanger tubes 1 through which low-temperature fluid flows, and which generate airflow in the direction of the arrow 2. Furthermore, porous plates 6 and 7 are arranged at the inlet and outlet of the heat transfer tube 1 to prevent the solid particles 5 filled therein from falling and scattering, respectively, to constitute a fluidized bed heat exchanger. Detectors 8 and 9 located at the inlet and outlet of the exchanger are detectors that directly detect absolute humidity, and use, for example, ZrO ₂ --MgO ceramics as sensor elements. and detectors 8, 9
is connected to a control device 10 that controls the motor 4 for the blower 3. FIG. 2 is an electrical circuit diagram of the heat exchange device shown in FIG. 1, in which a cycle device 11 through which low-temperature fluid flows is connected to a power source 13 via an operation side of an operation/stop switch 12. Further, in parallel with the cycle equipment 11, a relay 14 is connected to a power source 13 via the operation side of the operation/stop switch 12. The motor 4 for the blower 3 is connected to the power source 13 via the contact 15 of the relay 14 and the operation side of the operation/stop switch 12. Here, when the relay 14 is energized, it instantly closes the contact 15,
This is a type of relay that instantly opens the contact 15 when the power supply is stopped. Further, the aforementioned control device 10 is connected to the power source 13 via the stop side of the run/stop switch 12, and the motor 4 for the blower 3 is connected via the contact 16 of the control device 10 and the stop side of the run/stop switch 12. It is connected to the power supply 13. Here, the control device 10 closes the contact 16 when power is stopped, detects signals from the detectors 8 and 9 when the power is turned on, and controls the contact 16 to open if both absolute humidity values are equal.

Next, the operation of the above configuration will be explained. driving·
When the stop changeover switch 12 is set to the operating side, the cycle equipment 11 that flows low-temperature fluid is activated, and the relay 1 is activated.
4 is also energized, so contact 15 closes and blower 3
The motor 4 also operates. Therefore, since the blower 3 starts operating, an air current is generated, and the solid particles 5 start floating and flowing around the outer periphery of the heating tube 1. Further, heat exchange is performed between the low temperature fluid flowing inside the heat exchanger tube 1 and the airflow generated by the blower 3. At this time, when the floating solid particles 5 collide with the heat transfer tube 1, the temperature boundary layer is destroyed and the heat transfer coefficient is significantly improved. When the heat exchanger tube temperature becomes lower than the dew point temperature of the surrounding air, dew condensation occurs on the heat exchanger tube surface. Therefore, water gradually adheres to the floating and flowing solid particles 5.

Next, when the operation/stop switch 12 is set to the stop side, the cycle equipment 11 stops operating and the low temperature fluid stops. Also, since the relay 14 is no longer energized, the contact 15 is opened, but the normally closed contact 1
Since the motor 4 for the blower 3 is energized via the motor 6, the blower 3 continues to operate. Also, since the control device 10 is energized, the control device 10 detects absolute humidity signals from the detectors 8 and 9.

At this time, since the low-temperature fluid is stopped, no heat exchange takes place, but material exchange takes place between the air flow generated by the blower 3 and the moisture attached to the solid particles 5. The attached moisture then evaporates and is discharged to the outside of the heat exchange device by the airflow. Therefore, while moisture is attached to the solid particles 5, the absolute humidity value indicated by the detector 9 is higher than the value indicated by the detector 8. Here, the control device 10 performs control to open the contact 16 if the absolute humidity values indicated by the detectors 8 and 9 are equal, so the blower 3 continues to operate until the solid particles 5 are dried.

Therefore, even when the operation of the cycle equipment 11 is restarted, good fluidity can be obtained, and the desired function of the fluidized bed heat exchanger can be fully performed. Furthermore, since the control is performed based on changes in absolute humidity, the removal of moisture from the solid particles 5 is directly detected, so reliability is high. Although ZrO ₂ --MgO ceramics were used as a sensor element in one embodiment, the present invention has been described, but it goes without saying that sufficient effects can be obtained by using other detectors that detect absolute temperature.

Effects of the Invention A fluidized bed heat exchanger comprising a plurality of heat exchanger tubes and solid particles floating and flowing around the outer periphery of the plurality of heat exchanger tubes, and a fluidized bed heat exchanger that measures absolute humidity changes of air at the inlet and outlet of the fluidized bed heat exchanger. This heat exchange equipment is equipped with a control device that uses a detector to stop the blower, so even when the cycle equipment is stopped and restarted, it has good fluidity because no moisture is attached to the solid particles. is obtained, the temperature boundary layer is destroyed, and the heat transfer coefficient is greatly improved. Therefore, the heat transfer area can be reduced, and the heat exchange device can be made smaller. Furthermore, since control is performed based on changes in absolute humidity, the removal of water from solid particles can be directly detected, resulting in high reliability. In addition, if fluidity is improved as mentioned above, even when frosting occurs, the frost layer will be compressed evenly and the height of frost adhesion will be lowered, preventing a decrease in the air passage area and reducing air volume. . Furthermore, the frost layer is compressed to become an ice layer with high thermal conductivity, reducing thermal resistance, thereby significantly reducing the reduction in heat exchange amount.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a heat exchange device according to an embodiment of the present invention, and FIG. 2 is an electric circuit diagram of the heat exchange device. 1...Heat transfer tube, 3...Blower, 4...Blower motor, 5...Solid particles, 8, 9...Detector, 1
0...control device.

Claims (1)

[Claims] 1. A fluidized bed heat exchanger including a plurality of heat exchanger tubes and solid particles floating and flowing around the outer periphery of the plurality of heat exchanger tubes, and detecting changes in absolute humidity of air at the inlet and outlet of the fluidized bed heat exchanger. A heat exchange device comprising a detector, a blower that generates an airflow passing through the fluidized bed heat exchanger, and a control device that uses the detector to stop the blower.