Patent Application
20230417453
The present invention relates to a temperature control apparatus that controls the temperature of a load at a desired temperature by supplying temperature-controlled circulating liquid to the load.
A temperature control apparatus that controls the temperature of a load at a desired temperature by supplying temperature-controlled circulating liquid to the load is already widely known, as disclosed in PTL 1, for example. The temperature control apparatus described in the PTL includes a circulation circuit for circulating circulating liquid to and from a load and a cooling circuit for cooling the circulating liquid. The circulation circuit and the cooling circuit are connected to each other through a tank and a valve.
In some cases, as described in PTL 1, the temperature control apparatus is used to control the load at a temperature that greatly exceeds the boiling point of water (100° C.) under atmospheric pressure in a semiconductor manufacturing device or the like. In temperature control apparatuses in which the circulating liquid is at a high temperature, the temperature difference between the high-temperature circulating liquid and a cooling liquid that cools the circulating liquid becomes significantly large, in particular, in a heat exchanger. Accordingly, it is necessary to take measures to prevent the damage to the heat exchanger caused by the temperature difference.
For this reason, the temperature control apparatus described in PTL 1 employs a heat exchanger with a specialized structure that can withstand such a temperature difference. However, it is expected that a temperature control apparatus is developed that even when the circulating liquid is to be used at high temperatures, the temperature control apparatus can employ a heat exchanger designed in a variety of ways in accordance with user's requirements, such as low cost and high heat efficiency. That is, it is expected that a temperature control apparatus is developed having excellent general versatility and safety in terms of the temperature of the circulating liquid.
PTL 1: Japanese Unexamined Patent Application Publication No. 2020-169760
A technical problem of the present invention is to provide a temperature control apparatus that has a high degree of freedom in designing a heat exchanger even when the circulating liquid is used at a high temperature and that has excellent general versatility in terms of the temperature of the circulating liquid.
To solve the above-described technical problem, a temperature control apparatus according to the present invention adjusts the temperature of circulating liquid, supplies the circulating liquid to a load that is external, and controls the temperature of the load at a predetermined temperature. The temperature control apparatus includes a circulation circuit, where the circulation circuit includes a main tank storing circulating liquid and including a heater configured to heat the circulating liquid, a discharge flow passage configured to connect the main tank to a circulating liquid discharge port configured to deliver the circulating liquid to the load, a circulation pump configured to deliver the circulating liquid from the main tank to the discharge flow passage, and a return flow passage configured to connect a circulating liquid return port configured to receive the circulating liquid returned from the load to the main tank, a cooling circuit, where the cooling circuit includes a sub-tank storing the circulating liquid, a heat exchanger configured to cool the circulating liquid in the sub-tank by heat exchange with heat dissipating water, a first cooling flow passage configured to connect the sub-tank to the heat exchanger and guide the circulating liquid in the sub-tank to the heat exchanger, a cooling pump configured to deliver the circulating liquid in the sub-tank to the first cooling flow passage, and a second cooling flow passage configured to connect the heat exchanger to the sub-tank and guide the circulating liquid cooled by the heat exchanger to the sub-tank, and a processor configured to control the flow rate of the circulating liquid flowing through the cooling circuit. The sub-tank is connected to the main tank such that when the amount of the circulating liquid in the main tank exceeds a predetermined amount, excessive circulating liquid is led from the main tank to the sub-tank. The second cooling flow passage of the cooling circuit includes a connecting flow passage that branches from the second cooling flow passage and that is connected to the circulation circuit. The circulation circuit includes a temperature sensor configured to measure the temperature of the circulating liquid flowing in the circulation circuit, and the processor controls an output of the cooling pump based on the temperature of the circulating liquid measured by the temperature sensor so as to control the flow rate of the circulating liquid supplied from the inside of the cooling circuit to the inside of the circulation circuit through the connecting flow passage.
In this case, preferably, the main tank includes an opening that leads the excessive circulating liquid out of the main tank to the sub-tank, and the main tank is connected to the sub-tank with the opening positioned higher than a bottom surface of the sub-tank.
In addition, preferably, the processor is configured to switch the cooling pump between a first power output range and a second power output range that is greater than the first power output range on the basis of the temperature of the circulating liquid measured by the temperature sensor and drive the cooling pump. As a result, during driving of the cooling pump in the first power output range, the circulating liquid in the cooling circuit is circulated in the cooling circuit without being supplied to the circulation circuit through the connecting flow passage. In contrast, during driving of the cooling pump in the second power output range, the circulating liquid in the cooling circuit is supplied to the circulation circuit through the connecting flow passage while being circulated in the cooling circuit.
In addition, preferably, the connecting flow passage branches from the second cooling flow passage of the cooling circuit and extends upward.
In addition, preferably, the temperature sensor is a first temperature sensor provided in the discharge flow passage, and the processor compares a preset target temperature with the temperature of the circulating liquid measured by the first temperature sensor. If the measured temperature measured by the first temperature sensor is lower than the target temperature, the processor drives the cooling pump in the first power output range. If the measured temperature measured by the first temperature sensor is higher than the target temperature, the processor drives the cooling pump in the second power output range.
In addition, preferably, the measured temperature measured by the first temperature sensor is lower than the target temperature, the processor further controls the heater and heats the circulating liquid in the main tank.
In addition, preferably, the connecting flow passage includes a second temperature sensor configured to measure the temperature of the circulating liquid. During driving of the cooling pump in the second power output range, the processor calculates a temperature difference between the target temperature and the measured temperature measured by the second temperature sensor, compares the temperature difference with a preset reference value, and decreases the output of the cooling pump within the second power output range with increasing temperature difference from the reference value.
In addition, preferably, the heat exchanger includes a hollow case, at least three heat transfer plates arranged in parallel with a gap therebetween inside the case, a series of first heat exchange flow passages and a series of second heat exchange flow passages alternately formed from the gaps between the heat transfer plates in an arrangement direction of the heat transfer plates, a circulating liquid inlet provided at one end of the first heat exchange flow passage, where the circulating liquid inlet is connected to the first cooling flow passage, a circulating liquid outlet provided at the other end of the first heat exchange flow passage opposite to the circulating liquid inlet, where the circulating liquid outlet is connected to the second cooling flow passage, a heat dissipating water inlet provided at one end of the second heat exchange flow passage, where the heat dissipating water inlet is used to lead heat dissipating water to the second heat exchange flow passage, and a heat dissipating water outlet provided at the other end of the second heat exchange flow passage opposite to the heat dissipating water inlet, where the heat dissipating water outlet is used to discharge the heat dissipating water subjected to heat exchange from the second heat exchange flow passage.
In the temperature control apparatus according to the present invention, the heat exchanger does not directly cool a circulating liquid flowing through the circulation circuit connected to the main tank and the heat load and, when the amount of the circulating liquid exceeds a predetermined amount, the heat exchanger cools the excessive circulating liquid that has cooled by the low-temperature circulating liquid in the sub-tank. Therefore, even if the circulating liquid in the circulation circuit is to be used at a high temperature, the temperature difference between the circulating liquid and the cooling liquid in the heat exchanger can be reduced. As a result, according to the present invention, a temperature control apparatus can be provided that has a high degree of freedom in designing the heat exchanger and that is excellent in versatility and safety in terms of the temperature of the circulating liquid.
As illustrated in
The main tank 5, the sub-tank 20, the circulation circuit 12, the heat exchanger 33, the cooling circuit 25 and the control unit 40 are all housed in the housing 3. Furthermore, as is described in detail below, a side surface of the outer circumference of the housing 3 has, formed therein, a circulating liquid discharge port 3a and a circulating liquid return port 3b of the circulation circuit 12 and a cooling liquid supply port 3c and a cooling liquid discharge port 3d for the cooling liquid supplied to the heat exchanger 33. As a result, pipes of a target apparatus (a load) subject to temperature control on a user side can be connected to the openings (the ports) 3a, 3b, 3c, and 3d.
In addition, a drain pan 50 for receiving leaked circulating liquid is disposed on the bottom of the housing 3. The drain pan 50 includes a float-type water leakage sensor 51 electrically connected to the control unit 40 and a drain port 52 for discharging liquid accumulated in the drain pan 50 to the outside. As a result, for example, when the water leakage sensor 51 detects that a large amount of circulating liquid leaks in the apparatus 1, the control unit 40 can send a notification and turn off the power of the apparatus 1.
As the circulating liquid, a fluorinated liquid having a boiling point of about 200° C. or higher under atmospheric pressure is used, for example. As the cooling liquid, industrial water having a boiling point of 100° C. under atmospheric pressure is used, for example. According to the present embodiment, as illustrated in
Furthermore, according to the present embodiment, the circulating liquid that is cooled to 25° C. by the heat exchanger 33 is also supplied to the main tank 5 through the connecting flow passage 28. In contrast, the cooling liquid supplied to the heat exchanger 33 through the cooling liquid supply port 3c is heated to 27° C. by heat exchange with the circulating liquid and is discharged from the heat exchanger 33 through the cooling liquid discharge port 3d.
As described above, according to the apparatus 1, as illustrated in
According to the present embodiment, as illustrated in
Inside the main tank 5, a partition wall 5b having a height lower than the aqueous surface of the circulating liquid stored to a predetermined depth is installed upright on the bottom surface of the main tank 5. As a result, the interior of the main tank 5 is divided into two chambers, that is, a first chamber 6 partitioned by one side wall of the main tank 5 and the partition wall 5b and a second chamber 7 partitioned by the partition wall 5b and the other side wall.
Inside the main tank 5, the first chamber 6 and the second chamber 7 communicate with each other through a gap 8 formed in the main tank 5 above the upper end of the partition wall 5b. In addition, an opening 5c is formed at an upper end portion of the side surface of the main tank 5 to open to the sub-tank 20. Thus, the excessive circulating liquid exceeding the maximum capacity of the main tank 5 is discharged into the sub-tank 20. In addition, as illustrated in
As illustrated in
The first chamber 6 of the main tank 5 is provided with an immersion type circulation pump 18 that delivers the circulating liquid to the circulation circuit 12. The circulation pump 18 is also controlled by the control unit 40. Note that according to the present embodiment, inverter-controlled pumps are used as the circulation pump 18 and a cooling pump 55 (described below).
A total of four level switches 21a, 21b, 21c, and 21d are provided inside the sub-tank 20: one above the center in the depth direction of the sub-tank 20 and three arranged in the vertical direction below the center. The level switches 21a to 21d are also electrically connected to the control unit 40. Furthermore, a level gauge 22 for visually checking the amount of circulating liquid in the sub-tank 20 from outside the housing 3 and a circulating liquid fill port 23 for refilling the circulating liquid from outside the housing 3 to the sub-tank 20 are provided on the outer periphery of the sub-tank 20. In addition, a filling pipe 24 with its upper end connected to the side surface of the sub-tank is provided on the side surface so as to extend downward, and a drain cock 24a is attached to an end portion of the filling pipe 24. By opening the drain cock 24a, the drain cock 24a functions as a fill port for the circulating liquid, and the circulating liquid can be pumped into the sub-tank 20. Then, the four level switches 21a, 21b, 21c, and 21d detect the level (the liquid level) of the circulating liquid in the sub-tank 20, thus prompting a user to refill the sub-tank 20 with circulating liquid through the circulating liquid fill port 23 or refill the sub-tank 20 with circulating liquid by opening the drain cock 24a.
As illustrated in
At this time, the return flow passage 14 is connected to the second chamber 7 having the heater 10 disposed therein on the upstream side in the main tank 5. According to the configuration, even if the temperature of the circulating liquid returned from the return flow passage 14 to the main tank 5 changes, the circulating liquid returned to the second chamber 7 is subjected to temperature control by the heater 10 and the circulating liquid from the cooling circuit 25 and is delivered to the discharge flow passage 13, so that the circulating liquid having a more accurately adjusted temperature can be supplied to the load.
The discharge flow passage 13 has a pressure sensor 60, a first temperature sensor (temperature sensor) 61, and a flow rate sensor 62 disposed therein from the upstream side to the downstream side, and a third temperature sensor 63 is provided in the return flow passage 14. The pressure sensor 60, the first and third temperature sensors 61 and 63, and the flow rate sensor 62 are all electrically connected to the control unit 40. As a result, the heater 10, the cooling pump 55, and the circulation pump 18 can be appropriately controlled on the basis of the measured values from the sensors 60 to 63, for example.
As illustrated in
As illustrated in
As illustrated in
As illustrated in
The circulating liquid that has entered from the circulating liquid inlet 38a passes through the first heat exchange flow passage 36 and exits from the circulating liquid outlet 38b. In contrast, the cooling liquid that has entered from the cooling liquid inlet 38c passes through the second heat exchange flow passage 37 and exits from the cooling liquid outlet 38d. Since the plate heat exchanger 33 having such a configuration exchanges heat between the circulating liquid and the cooling liquid in a complete counterflow manner, the heat exchanger 33 has advantages of high performance and extremely high thermal efficiency. In addition, the heat exchanger 33 is compact and lightweight, and can be installed in a small area.
As illustrated in
The setting item preset on the display/setting panel 41 is a delivery temperature, which is the target temperature of the circulating liquid supplied to the load. According to the present embodiment, the set value of the delivery temperature of the circulating liquid is, for example, 160° C., and the set value is input from the display/setting panel 41. Therefore, a method for controlling the cooling pump 55 and the circulation pump 18 using the control unit 40 in terms of the set temperature of the circulating liquid is described below with reference to
First, when the delivery temperature (the measured temperature) of the circulating liquid measured by the first temperature sensor 61 in the discharge flow passage 13 is lower than the set temperature, the inverter control cooling pump 55 is driven in a low rotational speed range (a first power output range) by the processor 43 of the control unit 40, and the rotational speed is maintained at a predetermined low rotational speed (low frequency), as illustrated in
When the measured temperature of the circulating liquid measured by the first temperature sensor 61 exceeds the target temperature, the heater 10 is turned OFF, and the driving of the cooling pump 55 is switched to driving in a high rotational speed range (a second power output range) to maintain a predetermined high rotational speed (high frequency) by the processor 43, as illustrated in
If the amount of circulating liquid in the main tank 5 exceeds a predetermined amount while the circulating liquid in the sub-tank 20 is being supplied to the main tank 5, an excessive circulating liquid flows into the sub-tank 20 through the opening 5c so that the temperature is decreased due to the low-temperature circulating liquid, and the temperature-lowered circulating liquid is cooled by the heat exchanger 33. Part of the circulating liquid cooled by the heat exchanger 33 is returned to the sub-tank 20, and the other circulating liquid is supplied to the main tank 5 through the connecting flow passage 28. Therefore, in the heat exchanger 33, since the temperature of the circulating liquid flowing into the heat exchanger 33 is decreased, the temperature difference between the circulating liquid and the cooling liquid to be heat-exchanged with the circulating liquid can be reduced.
Herein, the processor 43 may calculate the temperature difference between the target temperature of the circulating liquid flowing through the discharge flow passage 13 and the temperature measured by the second temperature sensor 30 while the cooling pump 55 is driven in the second power output range, compare the temperature difference with a preset reference value, and decrease the output of the cooling pump 55 within the second power output range as the temperature difference increases from the reference value. When the measured temperature of the circulating liquid flowing through the connecting flow passage 28 changes, the calculated temperature difference also changes, and the difference from the reference value also changes. Since the temperature of the circulating liquid flowing the connecting flow passage 28 decreases and the cold energy increases with increasing difference between the temperature difference and the reference value, the flow rate of the circulating liquid for cooling the high-temperature circulating liquid accumulated in the main tank 5 can be decreased. However, since the temperature of the circulating liquid flowing through the connecting flow passage 28 increases with decreasing difference between the temperature difference and the reference value and, thus, the cold energy decreases, it is necessary to increase the flow rate of the circulating liquid for cooling the high-temperature circulating liquid accumulated in the main tank 5. For this reason, when the temperature difference becomes greater than the reference value, the flow rate of the circulating liquid supplied to the main tank 5 can be decreased, so that the output of the cooling pump 55 can be reduced within the second power output range.
Note that the processor 43 may turn on the heater 10 when the third temperature sensor 63 detects that the temperature of the circulating liquid that flows through the return flow passage 14 and that is returned from the load is lower than a preset temperature. As a result, the circulating liquid returned from the load can be rapidly heated by the heater 10.
As described above, according to the present embodiment, the heat exchanger 33 does not directly cool the circulating liquid flowing through the circulation circuit 12 connected to the load and, when the amount of circulating liquid in the main tank 5 exceeds a predetermined amount, the heat exchanger 33 cools the excessive circulating liquid that has been cooled by the low-temperature circulating liquid in the sub-tank 20. For this reason, even if the circulating liquid in the circulation circuit 12 is to be used at high temperature, the temperature difference between the circulating liquid in the heat exchanger 33 and the cooling liquid for the circulating liquid can be reduced. As a result, even when the circulating liquid is to be used at high temperature, the temperature control apparatus 1 can be provided that has a high degree of freedom in designing (selecting) the heat exchanger 33 and that has excellent general versatility in terms of the temperature of the circulating liquid.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-103706 | Jun 2022 | JP | national |
