JP2522917B2 - Refrigeration equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a refrigerating apparatus used for a cooler such as a showcase, and an air conditioner.

(B) Prior art When frost adheres to the evaporator of the refrigeration system, the heat exchange capacity of the evaporator is significantly reduced. Therefore, as disclosed in JP-A-57-192752, the temperature of the evaporator is changed. In some cases, the temperature of the evaporator is detected, and when this temperature becomes equal to or lower than the temperature at which frost forms on the evaporator, the capacity of the compressor is lowered so that the temperature of the evaporator does not always become equal to or lower than the temperature at which frost forms.

(C) Problems to be Solved by the Invention In the above-described conventional device, when the temperature of the evaporator becomes equal to or lower than the set temperature, the capability of the compressor is reduced to prevent frost formation, and when the temperature of the evaporator becomes equal to or higher than the set temperature. Since the capacity of the compressor is frequently changed in order to prevent frost formation on the evaporator, such as an increase in the compression function, it is not preferable in terms of the durability performance of the compressor.

The present invention provides a refrigeration system that solves the above problems.

(D) Means for Solving the Problems The present invention is directed to a compressor when the temperature of the evaporator or the refrigerant pressure of the evaporator becomes equal to or lower than a first set value for preventing frost formation on the evaporator. Control means for suppressing an increase in the capacity of the compressor and variable means for decreasing the capacity of the compressor when the temperature (refrigerant pressure) of the evaporator becomes equal to or lower than a second set value lower than the first set value. It is designed to be installed in the container.

(E) Action First and second set values for preventing frost formation on the evaporator of the refrigerating apparatus are provided, and when the temperature (refrigerant pressure) of the evaporator becomes equal to or lower than the first set value, compression is performed. The capacity of the machine is suppressed so as not to rise, but the temperature of the evaporator (refrigerant pressure) is still
When the value becomes lower than the second set value, the capacity of the compressor decreases. Therefore, the temperature of the evaporator (refrigerant pressure) gradually rises and settles between the first and second set values,
The capacity of the compressor does not change frequently to prevent frost formation on the evaporator.

(F) Embodiment FIG. 1 is a refrigerant circuit diagram showing an embodiment of the device of the present invention, in which a variable capacity compressor (1), a condenser (2), and a pressure reducing element (the capacity of which varies depending on the frequency of an applied power source). 3) and evaporator (4)
And are sequentially connected in a ring shape.

(5) is a variable capacity controller that changes the frequency of the power source applied to the compressor (1), and detects the temperature of the room to be conditioned (6) cooled by the evaporator (4) by the room temperature sensor (7). The frequency of the power supply is changed according to the temperature difference between the detected temperature and the set temperature.

(8) is a sensor for detecting the temperature of the evaporator (4),
When the temperature of the evaporator (4) detected by this sensor falls below the first set value (2 ° C) as shown in Fig. 2, the frequency of the power source applied to the compressor (1) increases. Suppressing means (9) for prohibiting the increase in the capacity of the compressor (1)
When the detected temperature of the evaporator (4) becomes equal to or lower than the second set value (0 ° C.) lower than the first set value, the frequency of the power source applied to the compressor (1) is lowered to reduce the compressor. A variable means (10) for lowering the capacity of (1) is provided in the variable capacity controller (5).

The device of the present invention is configured as described above, and the refrigerant discharged from the compressor (1) returns to the compressor (1) via the condenser (2) -pressure reducing element (3) -evaporator (4). A cycle is formed and the conditioned chamber (6) is cooled. During such operation, the set temperature set by the customer is compared with the temperature in the room to be conditioned (6) detected by the room temperature sensor (7). If this temperature difference is large, the variable capacity controller (5) causes the compressor to move. When the frequency of the power supply applied to (1) is increased and the compressor (1) is operated with high capacity, and conversely the temperature difference is small, the capacity variable controller (5) supplies power to the compressor (1). The compressor (1) is operated at a low capacity with a low frequency.

When the temperature of the evaporator (4) becomes equal to or lower than the first set value (2 ° C.) for preventing frost formation on the evaporator at the point A shown in FIG. 2 during such operation, the sensor (8) The suppression means (9) receives the detection signal and inhibits the frequency of the power supply applied to the compressor (1) from increasing, and the detection signal from the room temperature sensor (7) applies the power to the compressor (1). Even if a command to increase the frequency is received, the capacity of the compressor (1) does not increase. Nevertheless, the temperature of the evaporator (4) is lowered and the second point for preventing the frost formation of the evaporator at the point B shown in FIG.
When the temperature falls below the set value (0 ° C.) of the sensor (8), the variable means (10) receives the detection signal from the sensor (8) and the frequency of the power source applied to the compressor (1) is lowered to lower the capacity of the compressor (1). Therefore, the temperature of the evaporator (4) gradually rises, exceeds the second set value (0 ° C.) at point C shown in FIG. 2, and becomes stable between the first and second set values. The capacity of the compressor (1) does not change frequently to prevent frost formation on the evaporator (4).

Although the compressor (1) whose capacity changes depending on the applied power frequency is used in the above embodiment, a compressor whose capacity changes with an unloader mechanism or a pole number converting mechanism may be used.

Further, instead of detecting the temperature of the evaporator (4), the refrigerant pressure of the evaporator (4) corresponding to this temperature may be detected.

(G) Effect of the Invention According to the present invention, the first for preventing the frost formation of the evaporator
Also, a second set value is provided, the second set value is set lower than the first set value, and the capacity of the compressor increases when the temperature of the evaporator (refrigerant pressure) becomes equal to or lower than the first set value. The temperature of the evaporator (refrigerant pressure) is lowered and the second
Since the capacity of the compressor is reduced when the value becomes lower than the set value of, the temperature of the evaporator (refrigerant capacity) gradually rises and the first
And the second set value, and since the ability of the compressor does not change frequently to prevent frost formation on the evaporator, the durability of the compressor can be improved.

[Brief description of drawings]

The drawings show an embodiment of the device of the present invention. FIG. 1 is a refrigerant circuit diagram, and FIG. 2 is a characteristic diagram showing a correlation between evaporator temperature and compression functional force. (1) ... Variable capacity compressor, (2) ... Condenser, (3) ...
Decompression element, (4) ... Evaporator, (5) ... Variable capacity controller,
(8) ... Sensor, (9) ... Suppressing means, (10) ... Variable means.

Front Page Continuation (72) Inventor Koji Nagae 180 Sakata, Oizumi-cho, Gunma Prefecture, Tokyo Sanyo Denki Co., Ltd. (72) Inventor Hisa Tokisaki 180 Sakata, Oizumi-cho, Gunma Prefecture Tokyo Sanyo Electric Co., Ltd. In-house (72) Inventor Kazunori Matsumoto 180 Sakata, Oizumi-cho, Gunma-gun Oozumi-cho, Tokyo Sanyo Electric Co., Ltd. (56) References JP 61-66038 (JP, A) JP 61-1963 (JP, A)

Claims (1)

(57) [Claims] 1. A refrigerating apparatus provided with a refrigeration circuit in which a variable capacity compressor, a condenser, a pressure reducing element and an evaporator are sequentially connected in an annular shape, and a variable capacity controller for changing the capacity of the compressor. Has a sensor for detecting the temperature of the evaporator or the pressure of the refrigerant of the evaporator, and provides first and second set values for preventing frost formation on the evaporator, and the second set value is the first set value. Is set lower than the set value of, and a suppression unit that suppresses an increase in the capacity of the compressor when the detected temperature (pressure) of the sensor becomes equal to or lower than the first set value, and the detected temperature (pressure) is set to the second set value. A refrigerating apparatus, wherein the capacity controller is provided with a variable means for reducing the capacity of the compressor when the value becomes equal to or less than a set value.