JP4061215B2 - Temperature control method for temperature chamber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a temperature control method of a thermostat, and more particularly, relates to a temperature control method of a thermostat which is to keep the temperature-controlled room at a constant temperature by combining and heating of the cooling and heating in the refrigerator.
[0002]
[Prior art]
As a temperature control to keep the room temperature of the thermostat at the set temperature, a method to turn on / off the heater for temperature control and heating while the refrigerator is in operation, ON / OFF of the refrigerator at the differential temperature set value In addition, the heater is operated when the refrigerator is turned off, or the temperature is raised using the outside air temperature or heat load without operating the heater, and various other methods are performed and proposed. ing. (For example, refer to Patent Document 1).
[0003]
[Patent Document 1]
Japanese Examined Patent Publication No. 7-69104 [0004]
[Problems to be solved by the invention]
In general, the method of turning the heater on and off while the refrigerator is in operation is excellent as a temperature control function, but there is a problem that the power consumption increases because the refrigerator is always operating. Further, there is a problem that moisture in the storage is lost by continuous operation of the refrigerator, and not only the sample in the storage is dried, but also frost formation on the cooler is increased.
[0005]
Further, in the method of turning the refrigerator on and off, the refrigerator and the heater are alternately operated, so that problems such as overcooling and overheating are likely to occur, temperature control accuracy is low, and temperature control heating Since a heater having a relatively large capacity is used, there is a problem that a large amount of power is consumed in the alternate operation of the refrigerator and the heater. Furthermore, the method of naturally raising the temperature with the heater turned off when the refrigerator is turned off has many unstable factors such as the frosting state on the cooler, the heat load inside the cabinet, and the outside temperature, which increases the temperature inside the cabinet. If it takes a long time and the stop time of the refrigerator becomes longer, the temperature of the sample may be affected.
[0006]
Therefore, the present invention is not only excellent in temperature control function and easy to control the temperature, but also can reduce power consumption, defrost the cooler when the refrigerator is stopped, and suppress the decrease in the humidity inside the refrigerator. An object of the present invention is to provide a temperature control method for an incubator that can be used.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a temperature control method for a thermostatic device according to the present invention is such that a cooler of a refrigerator is disposed in a temperature-controlled air passage provided in the inner wall of the thermostatic chamber, and a first heater is disposed above the cooler. and each comprise water receiving tray to the bottom, and the outlet of the temperature control air to the top of the temperature control air passage, only each set of suction port-compartment air in the lower part, a second heater before Symbol water pan portion The refrigerator is provided based on a preset temperature set value, a differential temperature set value for controlling the refrigerator, a proportional band temperature set value for controlling the first heater, and a temperature state in the refrigerator , A temperature control method for a thermostat equipped with a temperature controller for operating either the first heater or the second heater , wherein the temperature setting value (Ts) set in the temperature controller is 1 To control the operation of the heater Proportional band temperature set value (t1), a differential temperature set value (t2) for controlling the operation of the refrigerator with a value smaller than the proportional band temperature set value (t1), and the refrigerator stops operation. The cooling stop time set value (Ta) for using the running time for judgment and the temperature rise time set value (Tb) for using the time during which the internal temperature rises higher than the proportional band temperature set value for judgment ) Is set in advance, and according to the state of the internal temperature (T), the temperature controller is configured so that the internal temperature (T) is set to the temperature set value (Ts) and the proportional band temperature set value (t1) at the start of operation. ), The operation of performing the cooling operation by operating the refrigerator when the heater stop temperature (Ts + t1) is exceeded, and the internal temperature (T) is set to the temperature set value (Ts) and the differential temperature by the cooling operation. Setting value (t2) The operation of starting the heating operation by activating the second heater while stopping the refrigerator and stopping the cooling operation when the required refrigerator stop temperature (Ts-t2) is exceeded, and stopping the cooling operation The refrigerator in which the internal temperature (T) is determined from the temperature setting value (Ts) and the differential temperature setting value (t2) within a time period in which the elapsed time (Tc) does not exceed the cooling stop time setting value (Ta) When the starting temperature (Ts + t2) is exceeded, the second heater is stopped to end the heating operation, and the cooling operation is restarted by starting the refrigerator, and in the heating operation, the internal temperature (T) is When the elapsed time (Tc) from the start of the heating operation exceeds the cooling stop time set value (Ta) when the refrigerator starting temperature (Ts + t2) is not exceeded, the second heater is stopped and the second heater is stopped. 1 heater is operated, and an operation of performing a heat insulation operation for keeping the internal temperature near the temperature set value by PID control of the first heater, and the internal temperature (T) in the heat insulation operation is the heater stop temperature (Ts + t1). When exceeding, the first heater is stopped, and the state in which the internal temperature (T) exceeds the heater stop temperature (Ts + t1) is the elapsed time (Tc) after the first heater is stopped. When the rising time set value (Tb) is exceeded, the cooling operation is performed by operating the refrigerator, and when the internal temperature (T) does not exceed the heater stop temperature (Ts + t1) at the start of the operation, The inside temperature is controlled by operating one heater and performing the heat retaining operation by PID control .
[0008]
Furthermore, in the temperature control method , a heating operation immediately after the cooling operation by the refrigerator is completed is performed by the second heater .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
1 to 4 show one embodiment of a thermostat for explaining the temperature control method of the present invention. FIG. 1 is a sectional side view, FIG. 2 is a sectional front view, and FIG. A side view and FIG. 4 are sectional front views of essential parts. This thermostatic device forms a temperature control air passage 13 between a partition plate 11 provided on the back of the chamber and the thermostat back plate 12, and the circulation fan 14, A first heater 15, a cooler (cooling coil) 16, a water tray 17, and a second heater 18 are provided, a temperature-controlled air outlet 19 is provided at the upper part of the partition plate 11, and an internal air inlet 20 is provided at the lower part. Are provided. The air in the chamber is sucked into the temperature-controlled air passage 13 from the suction port 20 and heated or cooled by the first heater 15, the second heater 18 and the cooler 16, and then is stored from the outlet 19 by the circulation fan 14. Circulate within. In addition, since the refrigerator main body which circulates a refrigerant | coolant to a cooler can use the same thing as the past, illustration and description are abbreviate | omitted.
[0010]
The water tray 17 is for receiving the frost or ice that has adhered to the cooler 16 while the refrigerator is stopped, and has fallen down. A drain pipe 21 is provided at the part. The second heater 18 is provided with a flat heater on the bottom surface of the water tray 17, and the second heater 18 has a relatively large capacity compared to the first heater 15. A heater having a small capacity and a capacity that can promote melting of ice falling in the water tray 17 and evaporation of moisture is used.
[0011]
In this way, by providing the second heater 18 at the portion of the water tray 17, the second heater 18 is operated (ON) at an appropriate time zone to promote the evaporation of the water dropped in the water tray 17. Therefore, it can suppress that the humidity in a warehouse falls, and can suppress evaporation of the moisture from a sample. Moreover, since melting of the ice block falling in the water tray 17 can be promoted, drainage from the water tray 17 to the drain pipe 21 can be performed smoothly.
[0012]
Next, an example of the temperature control method in the thermostat formed as described above is an example of the operating state of the first heater, the second heater, and the cooler with respect to the change in the internal temperature in the flowchart shown in FIG. 5 and FIGS. It demonstrates based on the figure which shows. In FIG. 5, “yes” in each determination symbol is a downward arrow direction, and “no” is a horizontal arrow direction.
[0013]
First, as various values for performing temperature control, in order to control the proportional band temperature set value (t1) for controlling the operation (ON-OFF) of the first heater 15 and the operation (ON-OFF) of the refrigerator. Differential temperature setting value (t2), cooling stop time setting value (Ta) for using the time during which the refrigerator is stopped for judgment, and the time during which the internal temperature is higher than the proportional band temperature setting value Is set in advance for each temperature setting value (Ts). The differential temperature setting value (t2) is set to a value smaller than the proportional band temperature setting value (t1). For example, if the differential temperature setting value (t2) is 1 ° C., the proportional band temperature setting value (t1) Is set to about 1.5 ° C.
[0014]
With these respective set values, the heater stop temperature (Ts + t1) is determined from the temperature set value (Ts) and the proportional band temperature set value (t1), and the refrigerator is determined from the temperature set value (Ts) and the differential temperature set value (t2). The stop temperature (Ts−t2) and the refrigerator start temperature (Ts + t2) are determined.
[0015]
In the flowchart shown in FIG. 5, when the operation of the thermostat is started, the first heater 15, the second heater 18, and the cooler 16 are all OFF, and in step 101, the internal temperature (T) and the heater stop. When the temperature (Ts + t1) is compared and the internal temperature (T) exceeds the heater stop temperature (Ts + t1), the process proceeds to step 102 where the refrigerator is turned on, and the internal cooling operation by the refrigerator is started. The inside air sucked from the suction port 20 is cooled by the cooler 16, and the cooled temperature-controlled air is blown out from the outlet 19 into the inside by the circulation fan 14. Subsequently, the process proceeds to step 103, where the internal temperature (T) and the refrigerator stop temperature (Ts-t2) are compared, and the cooling operation is performed until the internal temperature (T) reaches the refrigerator stop temperature (Ts-t2). Will continue.
[0016]
In step 103, when it is determined that the internal temperature (T) is lower than the refrigerator stop temperature (Ts-t2), the routine proceeds to step 104, where the refrigerator is turned off, and at the same time, the timer is started and the refrigerator is turned off. Measurement of the elapsed time (Tc) from when the second heater 18 starts is started, and in step 105, the second heater 18 is turned on. As a result, the heating operation by the second heater 18 starts, and the internal air sucked from the suction port 20 is heated by the second heater 18. The temperature-controlled air heated by the second heater 18 is melted by exchanging heat with frost or ice when passing through the cooler 16 to defrost the cooler 16 and the temperature-controlled air itself is It becomes a cooled state and is blown out from the outlet 19 into the cabinet by the circulation fan 14.
[0017]
In the next step 106, the preset cooling stop time set value (Ta) is compared with the elapsed time (Tc) after the refrigerator stops, and this elapsed time (Tc) is used as the cooling stop time set value (Ta). If not exceeded, the routine proceeds to step 107, where the internal temperature (T) is compared with the refrigerator start temperature (Ts + t2). When the internal temperature (T) does not exceed the refrigerator start temperature (Ts + t2), the process returns to step 106. When the internal temperature (T) exceeds the refrigerator starting temperature (Ts + t2) in step 107, the second heater 18 is turned off in step 108, and then the operation returns to step 102 to turn on the refrigerator and restart the cooling operation. The above procedure is repeated.
[0018]
On the other hand, when it is determined in step 106 that the elapsed time (Tc) after the refrigerator has stopped exceeds the cooling stop time set value (Ta), the routine proceeds to step 109, where the second heater 18 is turned off, and then to step 110. The first heater 15 is turned on. The temperature control by the first heater 15 is performed by the conventional PID control. By turning the first heater 15 on and off at predetermined time intervals, the internal temperature is brought close to the temperature set value (Ts). Insulation operation is performed to maintain.
[0019]
On the other hand, in the comparison of the internal temperature (T) in Step 101 and the heater stop temperature (Ts + t1) at the start of operation of the thermostat, the internal temperature (T) does not exceed the heater stop temperature (Ts + t1). When it is determined, the process proceeds directly from step 101 to step 110 to enter the heat insulation operation state.
[0020]
This heat retention operation is continued until the internal temperature (T) exceeds the heater stop temperature (Ts + t1) by comparing the internal temperature (T) with the heater stop temperature (Ts + t1) in the next step 111. If it is determined in step 111 that the internal temperature (T) has exceeded the heater stop temperature (Ts + t1), the routine proceeds to step 112 where the first heater 15 is turned off, and at the same time, the timer is started and the first heater 15 is turned off. Elapsed time (Tc) after becoming. In this state, the first heater 15, the second heater 18, and the cooler 16 are all OFF, and the internal temperature (T) naturally rises depending on the internal heat load and the outside air temperature. Or descend.
[0021]
During this time, in step 113, the internal temperature (T) and the heater stop temperature (Ts + t1) are compared, and when the internal temperature (T) falls to the heater stop temperature (Ts + t1), the process returns to step 110 to return to the first heater. 15 is turned ON, and the heat insulation operation is resumed. On the other hand, when it is determined in step 113 that the internal temperature (T) has exceeded the heater stop temperature (Ts + t1), the routine proceeds to step 114 where the elapsed time (Tc) after the first heater is turned off and the temperature rise time setting. When the elapsed time (Tc) does not exceed the temperature rise time set value (Tb), the process returns to step 113.
[0022]
If it is determined in step 114 that the elapsed time (Tc) after turning off the first heater has exceeded the temperature rise time set value (Tb), the process returns to step 102 and the refrigerator is turned on to restart the cooling operation. The Hereinafter, the above procedure is repeated according to the change in the internal temperature (T), whereby the internal temperature (T) is controlled to a temperature corresponding to the temperature set value (Ts).
[0023]
For example, the internal temperature (T) at the start of operation of the thermostat is higher than the heater stop temperature (Ts + t1) (step 101), and the state of the internal heat load and the outside air temperature tends to increase the internal temperature (T). In the state, as shown in FIG. 6, first, the refrigerator is turned on to perform a cooling operation (step 102), and the internal temperature (T) exceeds the refrigerator stop temperature (Ts-t2) by the cooling operation. (Step 103), the refrigerator is turned off to end the cooling operation (step 104), and the second heater is turned on to perform the heating operation (step 105). When the elapsed time (Tc) of the heating operation does not exceed the cooling stop time set value (Ta) (step 106) and the internal temperature (T) exceeds the refrigerator start temperature (Ts + t2) ( Step 107), the second heater 18 is turned off to end the heating operation (Step 108), and the procedure of starting the refrigerator and restarting the cooling operation (Step 102) is repeated.
[0024]
Further, when the rise in the internal temperature (T) due to the internal heat load or the outside air temperature is relatively gradual, first, as shown in FIG. 102) When the internal temperature (T) exceeds the refrigerator stop temperature (Ts-t2) by the cooling operation (step 103), the refrigerator is turned off and the cooling operation is terminated (step 104). A heating operation is performed with the second heater turned on (step 105). When the temperature rise due to this heating operation is slow and the elapsed time (Tc) exceeds the cooling stop time set value (Ta) before the internal temperature (T) exceeds the refrigerator start temperature (Ts + t2) (step) 106), the second heater 18 is turned off (step 109), the first heater 15 is turned on, and the heat insulation operation by PID control is started (step 110).
[0025]
Further, when the rise in the internal temperature (T) due to the internal heat load and the outside air temperature is extremely gradual, as shown in FIG. 8, the refrigerator is turned on (step 102) as in FIG. ), The refrigerator is turned off (step 103, step 104) due to a drop in the internal temperature (T), the second heater is turned on (step 105), and the second heater 18 is turned off when the elapsed time (Tc) is exceeded (step 109). ) And ON of the first heater 15 (step 110), the first heater 15 is continuously turned on, the internal temperature (T) is raised to the temperature set value (Ts), and then the same warming operation state as described above It becomes.
[0026]
On the other hand, as shown in FIG. 9, when the internal temperature (T) exceeds the heater stop temperature (Ts + t1) in the heat insulation operation state by the PID control of the first heater 15 (step 111), the first heater 15 is turned off. (Step 112), and monitors whether the internal temperature naturally falls due to the latent heat of the ice attached to the cooler 16 or the outside air temperature and returns to the proportional band temperature range (step 113), and the temperature rise time When the internal temperature falls below the heater stop temperature (Ts + t1) within the time set to the set value (Tb), that is, when the temperature falls to the proportional band temperature, the PID control by the first heater 15 is resumed (step 110). When the high (T) state exceeds the time set for the temperature rise time set value (Tb) (step 114), the temperature drops to the proportional band temperature range in the natural state. It is determined that there is no Start refrigerator (step 102), it resumes the cooling operation in the refrigerator.
[0027]
Further, as shown in FIG. 10, when the internal temperature (T) is equal to or lower than the heater stop temperature (Ts + t1) due to the thermal load in the internal chamber or the outside air temperature at the start of operation of the thermostat (step 102) PID control by the first heater 15 is started without turning on the refrigerator (step 110).
[0028]
In controlling the inside temperature in this way, after the operation of the refrigerator is stopped (OFF), the second heater 18 is turned on to perform the heating operation, whereby the inside air sucked from the suction port 20 is Since it will be in the state which passes through the cooler 16 after being heated with the 2nd heater 18, defrost and deicing of the cooler 16 can be performed, and the cooling efficiency falls by frost formation to the cooler 16 and icing. Can be suppressed. Further, at this time, the temperature-controlled air passing through the cooler 16 is appropriately cooled by exchanging heat with frost and ice, so that the temperature inside the chamber is higher than that when the temperature-controlled air is heated by the first heater 15. The rise is also relatively gentle. Thereby, since the stop time of a refrigerator can be lengthened moderately, the defrosting and de-icing of the cooler 16 can be performed effectively. In addition, since the evaporation of water in the water tray 17 is also promoted during the heating operation, it is possible to reliably suppress a decrease in the humidity in the cabinet.
[0029]
Furthermore, by using a heater with a smaller heater capacity than the first heater 15 as the second heater 18, it is possible to reduce the amount of power consumed during the heating operation. Since it can be performed effectively, the reduction in cooling efficiency can be suppressed, and the amount of power consumption in the refrigerator can be reduced.
[0030]
【The invention's effect】
As described above, according to the present invention, reliable temperature control can be performed while reducing power consumption. Also, evaporation of moisture from the sample can be suppressed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional side view showing an example of a thermostat for explaining a temperature control method of the present invention.
FIG. 2 is a sectional front view of the same.
FIG. 3 is a sectional side view of the main part of the same.
FIG. 4 is a sectional front view of the main part of the same.
FIG. 5 is a flowchart showing an example of a temperature control method of the present invention.
FIG. 6 is a diagram illustrating a first operation state example of the first heater, the second heater, and the cooler with respect to a change in the internal temperature.
FIG. 7 is a diagram illustrating a second operation state example of the first heater, the second heater, and the cooler with respect to a change in the internal temperature.
FIG. 8 is a diagram showing a third operation state example of the first heater, the second heater, and the cooler with respect to a change in the internal temperature.
FIG. 9 is a diagram illustrating a fourth operation state example of the first heater, the second heater, and the cooler with respect to a change in the internal temperature.
FIG. 10 is a diagram illustrating a fifth operation state example of the first heater, the second heater, and the cooler with respect to a change in the internal temperature.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Partition plate, 12 ... Constant temperature apparatus back plate, 13 ... Temperature control air path, 14 ... Circulation fan, 15 ... 1st heater, 16 ... Cooler, 17 ... Water tray, 18 ... 2nd heater, 19 ... Air outlet , 20 ... Suction port, 21 ... Drain pipe

Claims (2)

The cooler of the refrigerator is arranged in the temperature control air passage provided in the inner wall of the thermostat, the first heater is provided in the upper portion of the cooler, the water tray is provided in the lower portion, and the upper portion of the temperature control air passage. to the outlet of the temperature control air, only each set of suction port-compartment air in the lower part, a second heater provided with prior Symbol water pan portion, a preset temperature set value, and controls the refrigerator A temperature controller that operates any of the refrigerator, the first heater, and the second heater based on a differential temperature setting value, a proportional band temperature setting value that controls the first heater, and a temperature condition in the refrigerator; A temperature control method for a thermostat , comprising: a proportional band temperature set value (t1) for controlling the operation of the first heater with respect to a temperature set value (Ts) set in the temperature regulator; , The proportional band temperature setting value (t1 A differential temperature setting value (t2) for controlling the operation of the refrigerator with a smaller value, and a cooling stop time setting value (Ta) for using the time during which the refrigerator is stopped for judgment. The temperature rise time set value (Tb) for using the time during which the inside temperature rises above the proportional band temperature set value is used for the determination, depending on the situation of the inside temperature (T). The temperature controller is
When the internal temperature (T) exceeds the heater stop temperature (Ts + t1) obtained from the temperature set value (Ts) and the proportional band temperature set value (t1) at the start of operation, the refrigerator is operated to perform the cooling operation. What to do,
The refrigerator is stopped and cooled when the internal temperature (T) exceeds the refrigerator stop temperature (Ts-t2) obtained from the temperature set value (Ts) and the differential temperature set value (t2) by the cooling operation. An operation of ending the operation and starting the heating operation by operating the second heater;
The chamber internal temperature (T) is set to the temperature set value (Ts) and the differential temperature set value (t2) within a time that the elapsed time (Tc) from the stop of the cooling operation does not exceed the cooling stop time set value (Ta). The operation of restarting the cooling operation by stopping the second heater and ending the heating operation when the refrigerator starting temperature (Ts + t2) calculated from
When the internal temperature (T) does not exceed the refrigerator start temperature (Ts + t2) in the heating operation, the elapsed time (Tc) from the start of the heating operation exceeds the cooling stop time set value (Ta). Sometimes, the second heater is stopped, the first heater is operated, and the operation of performing a heat insulation operation for keeping the inside temperature near the temperature set value by PID control of the first heater;
The first heater is stopped when the internal temperature (T) exceeds the heater stop temperature (Ts + t1) in the heat insulation operation, and the internal temperature (T) exceeds the heater stop temperature (Ts + t1). , When the elapsed time (Tc) after the first heater has stopped exceeds the temperature rise time set value (Tb), an operation of operating a refrigerator and performing a cooling operation;
An operation of operating the first heater when the internal temperature (T) does not exceed the heater stop temperature (Ts + t1) at the start of operation and performing the heat insulation operation by PID control;
The temperature control method of the thermostat characterized by controlling the inside temperature by performing . The temperature control method for a thermostat according to claim 1 , wherein the heating operation immediately after the cooling operation by the refrigerator is completed is performed by the second heater .

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