JPH06341751A - Inside temperature controller for showcase - Google Patents

Abstract

PURPOSE:To provide an inside temperature controller for a showcase, which is capable of surely controlling the inside temperature by only one set of temperature sensor. CONSTITUTION:The input units of an inside temperature measuring unit or a temperature sensor S, an inside temperature setting unit 12, a clock circuit 13 and the like, the output unit of a valve driving unit 14 and the like for driving the opening and/or closing of a solenoid valve 3 in a refrigerating cycle, and a memory means (memory) 15 and the like, which stores data, are connected to a central operation processing unit(CPU) 11. The CPU 11 compares an inside temperature signal from the temperature sensor S with a set temperature stored in the memory 15 and outputs a valve opening and closing signal to a valve driving unit 14 based on the result of the comparison and the opening and closing time of the solenoid valve 3 of previous time to change the operating time of the refrigerating cycle by opening and/or closing the solenoid valve 3 with a predetermined period of time and keep the inside temperature at a predetermined temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a showcase internal temperature control device, and more specifically, it shows the internal temperature set in the internal temperature setting section and the internal temperature detected by the internal temperature measuring section. In comparison, the present invention relates to a device that controls the opening / closing time of a solenoid valve provided in a refrigeration cycle to control the temperature in a freezing / refrigerating showcase within a predetermined range.

[0002]

2. Description of the Related Art Generally, a refrigerating / refrigerating showcase is cooled by cooling a cooling coil by opening a solenoid valve in the refrigerating cycle to allow a refrigerant gas to flow through the cooling coil and cooling the air inside the duct with an air curtain. By cooling the internal air, the displayed products are cooled.

Conventionally, such a temperature control device for a showcase includes a refrigerator temperature setting unit and a refrigerator temperature measuring unit (temperature sensor), valve driving means for opening and closing an electromagnetic valve in the refrigeration cycle, and a refrigerator temperature. The temperature sensor installed in the showcase detects the temperature inside the showcase, which is composed of a control unit that operates the valve driving means by comparing the inside temperature set in the setting unit with the inside temperature detected by the inside temperature measurement unit. A means for opening and closing the solenoid valve based on the magnitude relationship between the value and a certain reference value to maintain the internal cold storage temperature within a certain range is generally adopted.

FIG. 8 shows a temperature change in the refrigerator when the solenoid valve is controlled with a constant temperature range of ± d ° C. by the conventional device. As is clear from FIG. 8, in the conventional device,
Immediately after the solenoid valve is turned on or off, the internal cold storage temperature does not drop or rise, and Δdon ° C rises after a certain Δton time or Δdoff ° C falls after a Δtoff time. This situation also varies depending on the load (difference between ambient temperature and internal temperature) and the sensor mounting position. For example, when the load is large, Δ in FIG.
There is a tendency that doff and Δtoff decrease, Δdon increases, and Δton decreases. Further, when the load is small, Δdoff tends to be large, Δtoff tends to become small, and Δdon and Δton tend to become small. Further, when the temperature sensor has poor response such as when mounted in a refrigerator, Δdon, Δdoff and Δto
Both n and Δtoff tend to increase.

[0005]

A showcase of the type in which the solenoid valve is opened to allow the refrigerant gas to flow through the cooling coil to cool the cooling coil to cool the air inside the duct and to cool the air inside the chamber with an air curtain. In, for example, when one temperature sensor is attached to the inside of the refrigerator and the solenoid valve is controlled with a constant temperature fluctuation range by the above-mentioned conventional device, the fluctuation range of the inside temperature tends to be large, and in terms of responsiveness. There's a problem.
Further, in such temperature control, in order to reduce the fluctuation range of the internal temperature, it is sufficient to narrow the temperature range of the reference value for operating the solenoid valve, but if the temperature range of the reference value is too narrow, the chattering phenomenon will occur. There is a limit because there is a possibility that such things will occur.

Therefore, in the conventional showcase, a plurality of temperature sensors are installed at different places in the showcase,
Control is performed based on the temperature sensed by these temperature sensors to reduce the fluctuation range of the temperature inside the refrigerator, but this requires complicated control.

Therefore, a temperature sensor is attached to the inside of the duct or the outlet to improve the responsiveness of the temperature sensor and suppress the fluctuation range. However, with this means, a constant temperature difference occurs between the inside of the refrigerator and the blowing duct, so that it becomes necessary to control the temperature to be lower than the original internal temperature of the refrigerator by a certain temperature. Moreover, since this temperature difference changes due to load fluctuations according to day and night and the four seasons, there is a problem that this means cannot sufficiently follow the load fluctuations in the refrigerator and the environmental fluctuations.

As described above, in the showcase, it is ideal that the sensor is attached to the portion to be controlled to control the temperature, but in the conventional control devices, there is a limit in reducing the fluctuation range. .

Therefore, as a result of repeated tests and research by the present inventors, the conventional control device is a temperature-based control in which the solenoid valve is ON-OFF controlled within a constant temperature range with respect to a set value. Looking at the ON / OFF time of the solenoid valve, almost constant control is performed, and it has been found that the fluctuation range can be reduced by shortening the ON / OFF time, and the present invention is completed. It has come.

An object of the present invention is to provide a showcase interior temperature control device capable of reliably controlling the interior temperature with only one interior temperature sensor.

[0011]

In order to achieve the above object, a temperature control device for a showcase in a store according to the present invention has an inside temperature setting unit and an inside temperature measuring unit, and the inside temperature setting unit is provided in the inside temperature setting unit. In a device that compares the set internal temperature with the internal temperature detected by the internal temperature measuring unit to control the internal temperature of the showcase to a predetermined temperature, a valve drive that opens and closes the solenoid valve in the refrigeration cycle Means, storage means for storing the opening time and closing time in one opening / closing cycle of the solenoid valve, and a change in the inside temperature of the inside of the opening / closing cycle of the solenoid valve detected by the inside temperature measuring unit and a storage in the storage means. And a calculation unit for setting the opening time and closing time of the next one cycle of the electromagnetic valve according to the opening time and closing time of the electromagnetic valve. That is, the device of the present invention controls the temperature control output (ON / OFF output of the solenoid valve) by time, and the time depends on the maximum / minimum value of the internal temperature, the internal temperature setting value, and the differential. Is set. Then, the temperature control output time is evaluated and updated for each cycle, the input from the temperature sensor is performed every few seconds (for example, every one second or every three seconds), and the minimum unit of temperature is, for example, 0.5. ℃
A degree is preferable.

When the temperature inside the refrigerator during one cycle of opening and closing the solenoid valve is higher than a predetermined temperature, the opening time of the solenoid valve is increased at a predetermined rate and the closing time is decreased at a predetermined rate. (Claim 2), while
When the temperature inside the refrigerator during one cycle of opening and closing the solenoid valve is lower than a predetermined temperature, the opening time of the solenoid valve is decreased at a predetermined rate and the closing time is increased at a predetermined rate. Item 3). In this case, the shortest opening time and the shortest closing time are set in advance as the opening time and closing time of the solenoid valve (claim 4).

[0013]

[Operation] When the temperature inside the refrigerator during one cycle of opening and closing the solenoid valve becomes lower than the preset temperature,
Shorten the opening time of the solenoid valve for the next cycle and lengthen the closing time. Similarly, when the internal temperature becomes higher than the set temperature range, shorten the closing time of the solenoid valve for the next cycle. And increase the opening time. If the maximum temperature and the minimum temperature in one cycle are within the set range, the open / close time is continued as it is. This makes it possible to control the internal temperature to a predetermined temperature.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail based on an embodiment shown in the drawings. FIG. 1 is an explanatory view of a mounting position of a temperature sensor in a showcase, FIG. 2 is an explanatory view of a refrigeration cycle, and FIG. 3 is a block diagram of a control device showing an embodiment of the present invention. 4 and 5 are flowcharts showing an example of the operation procedure of the device of the present invention, FIG. 4 shows a basic operation flow, and FIG. 5 shows opening / closing time of the solenoid valve (temperature control output ON / OFF time). ) Shows the operation of setting. Further, FIG. 6 is an explanatory diagram showing a temperature change in the refrigerator by the temperature control device of the present invention, and FIG. 7 shows another embodiment of the procedure for updating the temperature control output time. FIG.

First, the device of the present invention is provided in the refrigeration cycle 2 as shown in FIG. 2 based on the internal temperature signal from the temperature sensor S provided in the showcase 1 as shown in FIG. Open / close time of solenoid valve 3 (temperature control output ON, OFF
The showcase 1 is controlled by adjusting the opening time (temperature control output ON time) and closing time (temperature control output OFF time) of the solenoid valve 3 according to the change in the internal compartment temperature. The temperature inside the refrigerator is controlled to the set temperature. That is, the conventional control device performs temperature-based control of ON-OFF control of the solenoid valve 3 within a constant temperature range with respect to the set value, but the device of the present invention turns on the solenoid valve 3 in the conventional device. Paying attention to the fact that the OFF is performed at substantially constant intervals, the fluctuation range of the internal temperature is reduced by shortening the ON and OFF times.

FIG. 3 shows a basic configuration of the apparatus of the present invention. The central processing unit (CPU) 11 includes the temperature sensor S, which is an internal temperature measuring section, and the internal temperature setting section 1.
2. An input unit such as a clock circuit 13 and an output unit such as a valve drive unit 14 that drives the solenoid valve 3 in the refrigeration cycle 2 to open and close.
A storage means (memory) 15 for storing data is connected, and the CPU 11 compares the internal temperature signal from the temperature sensor S with the set temperature stored in the memory 15, and the result is compared with the memory 15. A valve opening / closing signal is output to the valve drive unit 14 based on the previous opening / closing time of the electromagnetic valve 3 stored in the memory, and the operating time of the refrigeration cycle is changed by opening / closing the electromagnetic valve 3 in a predetermined time. Try to keep the temperature at the specified temperature.

Next, referring to FIGS. 4 to 6, the procedure for controlling the temperature inside the refrigerator by the device of the present invention will be described. First, as shown in FIG. 4, the inside temperature detected by the temperature sensor S in step S1 is compared with the set value previously input from the setting unit 12, and when the inside temperature is less than the set value, Proceeds to step S2 to keep the electromagnetic valve 3 of the refrigeration cycle 2 in the closed state (temperature control output OFF state). In this state, the temperature inside the refrigerator is equal to or lower than the set value, and cooling is not required.

If the temperature inside the refrigerator is equal to or higher than the set value in step S1, the opening time (temperature control output ON time) and the closing time (temperature control output OFF time) of the solenoid valve are preset in step S3. Initial value (for example, ON time = 90
Seconds, OFF time = 90 seconds), the electromagnetic valve is opened in step S4 to bring the temperature control output to the ON state, and cooling of the inside of the refrigerator, that is, blowing of cold air is started. This open state of the solenoid valve (temperature control output ON state) is continued until the ON time elapses in step S5, and further continued until the internal temperature becomes equal to or lower than the set value in step S6.

When the internal cold storage temperature becomes equal to or lower than the set value in step S6, the solenoid valve is closed in step S7, and the closed state of the solenoid valve (temperature control output OFF state) is continued until the OFF time elapses in step S8. Further, in step S9, the process is continued until the internal temperature reaches or exceeds the set value.

Then, in step S10, the ON time and the OFF time are corrected and updated based on the change in the internal temperature due to the opening / closing of the solenoid valve (temperature control output ON / OFF). By this update of the temperature control output time, one cycle of opening and closing the solenoid valve is completed, new ON time and OFF time are set, the process returns to step S4, and the solenoid valve is opened.

In the next one cycle, the above steps S4 to S10 are repeated based on the updated ON time and OFF time, and thereafter, the ON / OFF time is corrected and updated as needed, while opening / closing the solenoid valve. Go through the cycle.

FIGS. 5 and 6 show an example of a correction (update) operation of the ON time and the OFF time in step S10. First, in step S11, the maximum temperature (MAX) in one cycle is compared with the internal temperature setting value,
The maximum temperature is + 1.0 ° C above the set value, as indicated by point A in Fig. 6.
In the above case, the process proceeds to step S12 and the OF of the solenoid valve is turned off.
Reduces F time by 50% and turns on in step S13
Increase time by 10%. When the difference between the maximum temperature and the set value is less than + 1.0 ° C in step S11, the process proceeds to step S14, and the maximum temperature is + 0.5 ° C or more with respect to the inside temperature setting value, as shown by point B in FIG. In case of, the process proceeds to step S15, the OFF time is reduced by 10%, and the ON time is increased by 5% in step S16. Further, in step S14, the temperature difference is + as shown by point C in FIG.
When the temperature is lower than 0.5 ° C., the process proceeds to the next lowest temperature step without increasing or decreasing the ON time and the OFF time.

On the next lowest temperature side, first, step S1
7, the minimum temperature (MIN) in one cycle is compared with the internal temperature setting value, and the temperature difference is − as shown by point D in FIG.
When the temperature is 1.0 ° C. or higher, the OFF time is increased by 10% in step S18, and the ON time is increased by 5 in step S19.
Reduce by 0%. In addition, the temperature difference in step S18 is −
When the temperature is lower than 1.0 ° C., the process proceeds to step S20, and FIG.
When the temperature difference is −0.5 ° C. or more, like point E of
The OFF time is increased by 5% in step S21, and the ON time is decreased by 10% in step S22. Further, in step S20, the temperature difference is -0.5 as shown by point F in FIG.
When the temperature is lower than 0 ° C, the ON time and the OFF time are maintained as they are.

As described above, the ON time of the solenoid valve and the OF
To increase or decrease the F time, the ON time or OFF time becomes extremely short as a result of the processing, and the chattering is prevented from occurring due to the solenoid valve opening / closing switching time becoming too short. It is desirable to set in advance and to provide a step for preventing the ON time and the OFF time from becoming shorter than the shortest time. In this case, since one time, for example, the ON time becomes the shortest time, the other OFF time is lengthened, so that the ON time and the OFF time can be balanced in an optimum state. It is possible to control the inside temperature to a set temperature.

Further, in this embodiment, the open state of the solenoid valve (temperature control output OFF state) is maintained until the temperature inside the refrigerator becomes equal to or lower than the set value in step S6, so external factors and defrosting are performed. Even if the temperature inside the refrigerator rises above the set value due to operation, etc., the solenoid valve is kept open (temperature control output ON state) separately from the above-mentioned time control, so that the inside of the refrigerator can be quickly adjusted to the predetermined value. Can be cooled to temperature.

The mounting position of the temperature sensor can be appropriately set according to the shape and configuration of the showcase, and the refrigeration cycle has been conventionally used in this type of showcase. It is possible to use the same structure as it is, and the open / close control of the solenoid valve can also employ various control means used in conventional temperature control, and is not particularly limited.

Next, another embodiment of the procedure for updating the temperature control output time in step S10 will be described with reference to FIG. In this embodiment, as shown in FIG. 7, a differential d is set up and down with a predetermined width with respect to a set value of the internal temperature, and the differential d causes an area A exceeding “set temperature + d” and a “setting The three temperature regions, that is, the region C below "Temperature-d" and the region B between them, are divided, and depending on which temperature region the maximum value (MAX) and the minimum value (MIN) of the temperature fluctuation in the chamber belong to. The fluctuation of the internal temperature is classified into four patterns, and the temperature control output ON / OFF time, that is, the temperature control output time is updated accordingly.

(Pattern 1) The maximum value belongs to the area A and the minimum value belongs to the area B. This temperature variation pattern is a state in which the inside temperature fluctuates a little, and it is necessary to increase the ON time of the temperature control output and reduce the OFF time. In addition, since the maximum value exceeds the differential + d, in this state, the inside temperature is usually greatly increased due to an external factor, etc., and the inside can be sufficiently cooled at the previous temperature control output ON time. It is in a state that could not be done, as shown in FIG.
In step S6 in step S6, the solenoid valve is held in the ON state for a time longer than the temperature control output ON time. Therefore, the new ON set time and O in this pattern
The FF setting time can be calculated by the following equation. Current ON setting time = Last ON setting time + (Previous actual ON time-Previous ON setting time) / 4 Current OFF setting time = Previous OFF setting time- (Previous actual ON time-Previous ON ON setting time) / 2

(Pattern 2) The maximum value belongs to the area B and the minimum value belongs to the area C. This temperature variation pattern is a state in which the inside temperature is fluctuating rather low, and it is necessary to control the ON time of the temperature control output to decrease and the OFF time to increase. Further, since the minimum value is less than the differential -d and the temperature is too cold, step S9 in FIG. 1 operates, and the solenoid valve is held in the OFF state for a time longer than the temperature adjustment output OFF time. Therefore, the new ON setting time and OFF setting time in this pattern can be calculated by the following equation. Current OFF setting time = Last OFF setting time + (Previous actual OFF time-Previous OFF setting time) / 4 Current ON setting time = Previous ON setting time- (Previous actual OFF time-Previous OFF OFF setting time) / 2

(Pattern 3) The maximum value belongs to the area A and the minimum value belongs to the area C. This temperature fluctuation pattern indicates that the fluctuation range of the internal temperature is large and that both the ON setting time and the OFF setting time of the previous time are long. Therefore, the ON time and the OFF time are both controlled to be decreased. There is a need. Therefore, the new ON set time and O in this pattern
The FF setting time can be calculated by the following equation. Current ON setting time = Previous ON setting time x 0.9 Current OFF setting time = Previous OFF setting time x 0.9

(Pattern 4) Both the maximum value and the minimum value belong to the area B. In this temperature fluctuation pattern, the fluctuation range of the internal temperature is in an appropriate range, and there is no particular problem if the ON setting time and the OFF setting time are kept as they are, but in order to control them more efficiently, Value, ie (maximum value + minimum value) / 2
Calculated, and set ON time and OFF according to this average value
Adjust the set time.

(A) When the average value> the set temperature in the refrigerator: In this state, the temperature in the refrigerator is slightly higher,
While slightly increasing the ON time of the temperature control output,
The F time may be controlled to be slightly decreased. Therefore, the new ON set time and O in this pattern
The FF setting time can be calculated by the following equation. Current ON setting time = Previous ON setting time + 2 seconds Current OFF setting time = Previous OFF setting time -1 second

(B) When the average value <the set temperature in the refrigerator: In this state, the temperature in the refrigerator is slightly low,
The ON time of the temperature control output is slightly reduced, and the OF
The F time may be controlled to be slightly increased. Therefore, the new ON set time and O in this pattern
The FF setting time can be calculated by the following equation. Current ON setting time = Previous ON setting time-1 second Current OFF setting time = Previous OFF setting time + 2 seconds

(C) When the average value is equal to the set temperature in the refrigerator In this state, the temperature in the refrigerator is within the set temperature range,
Moreover, since the average temperature matches the set temperature, the ratio of the ON set time and the OFF set time is appropriately maintained. Therefore, it is only necessary to control the inside temperature to approach the set temperature while maintaining this state.
At this time, it is sufficient to determine how much the fluctuation of the internal temperature is, and control the temperature control output as follows.

(A) When the maximum value = (set value + d) and the minimum value = (set value-d), the temperature fluctuation is large in this state. In order to make it smaller, the new ON setting time and OFF setting time may be updated as in the following equation. Current ON setting time = Last ON setting time -2 seconds Current OFF setting time = Last OFF setting time -2 seconds

(B) In other states, this state is controlled in the most preferable state, but the number of times the solenoid valve is turned on and off is reduced to reduce the load on the solenoid valve. It is preferable. Therefore, new ON setting time and OFF setting time may be set as in the following equation. Current ON setting time = Previous ON setting time + 2 seconds Current OFF setting time = Previous OFF setting time + 2 seconds

As described above, the maximum value (MAX) and the minimum value (MIN) of temperature fluctuations in the refrigerator are differential d.
On the other hand, by determining the relationship between them and updating the ON set time and the OFF set time, more detailed control becomes possible, and the interior of the refrigerator can be specified in a short time and efficiently. The temperature can be controlled. In addition,
The differential d is, for example, 0.5 [deg.] C., 1.
It can be set to 0 ℃, 1.5 ℃, 2.0 ℃, etc.,
Numerical values for correction in the above equations can also be set arbitrarily.

[0038]

As described above, the internal temperature control device for a showcase according to the present invention has the minimum temperature during cooling when the solenoid valve is opened and the non-cooling when the solenoid valve is closed in one cycle of opening and closing the solenoid valve. Since the opening / closing time of the solenoid valve in the next one cycle is controlled based on the maximum temperature in the inside, it becomes possible to finely control the cooling state inside the refrigerator, and it is possible to perform the optimal cooling inside the refrigerator. The inside temperature can be efficiently controlled within a predetermined temperature range.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a mounting position of a temperature sensor in a showcase.

FIG. 2 is an explanatory diagram of a refrigeration cycle.

FIG. 3 is a block diagram showing an embodiment of the device of the present invention.

FIG. 4 is a flowchart showing an example of an operation procedure in the device of the present invention.

FIG. 5 is a flowchart of a part for setting the opening / closing time of the solenoid valve.

FIG. 6 is an explanatory diagram showing a temperature change in the refrigerator.

FIG. 7 is a diagram for explaining another embodiment of the procedure for updating the temperature control output time.

FIG. 8 is an explanatory diagram showing a temperature change in the refrigerator when a solenoid valve is controlled by a conventional device.

[Explanation of symbols]

 1 Showcase 2 Refrigeration cycle 3 Solenoid valve 11 CPU 12 Setting part 13 Clock circuit 14 Valve drive part 15 Memory S Temperature sensor

Claims (4)

[Claims] 1. A show having an inside temperature setting unit and an inside temperature measuring unit, comparing the inside temperature set in the inside temperature setting unit with the inside temperature detected by the inside temperature measuring unit, and performing a show. In an apparatus for controlling a temperature inside a case to a predetermined temperature, a valve driving means for opening and closing an electromagnetic valve in a refrigeration cycle, a storage means for storing an opening time and a closing time in one opening and closing cycle of the electromagnetic valve, Opening and closing of the solenoid valve detected by the inside temperature measuring unit During one cycle, the opening and closing time of the solenoid valve for the next one cycle is determined according to the inside temperature of the inside and the opening and closing times of the solenoid valve stored in the storage means. An internal temperature control device for a showcase, comprising: a calculation unit for setting time and closing time. 2. When the temperature inside the refrigerator during one opening / closing cycle of the solenoid valve detected by the temperature inside measurement chamber is higher than the temperature inside the chamber set by the temperature setting unit inside the chamber, the calculation unit is configured to operate the electromagnetic wave. The temperature controller for the inside of the showcase according to claim 1, wherein the opening time of the valve is set to increase at a predetermined rate and the closing time is set to decrease at a predetermined rate. 3. When the temperature inside the refrigerator during one cycle of opening and closing the electromagnetic valve detected by the temperature inside measuring chamber is lower than the temperature inside the chamber set by the temperature setting unit inside the chamber, the calculation unit is configured to operate the electromagnetic valve. The temperature controller for the inside of the showcase according to claim 1, wherein the opening time of the valve is set to decrease at a predetermined rate and the closing time of the valve is set to increase at a predetermined rate. 4. The temperature control of the inside of the showcase according to claim 1, wherein the opening time and closing time of the solenoid valve are preset to the shortest opening time and the shortest closing time. apparatus.