JPH08110144A - Air-cooled conditioning unit for showcase having built-in refrigerating machine - Google Patents

Abstract

PURPOSE: To provide an air-cooled conditioning unit for a showcase provided with a built-in refrigerating machine, which is capable of continuing the cold- keeping operation of the refrigerating machine under an overload without raising the capacity of the refrigerating machine itself and high in load capacity. CONSTITUTION: In an air-cooled conditioning unit for a showcase with a built-in refrigerating machine, in which an air-cooled condenser 5 with a cooling fan 5a and a motor-driven compressor 6 are incorporated into the base 1a of a case main body 1 in tandem, an exhaust fan 7 is installed additionally at the back side of the motor-driven compressor. By this method, the exhaust fan 7 is operated upon the overload of the refrigerating machine by the operation of a high-pressure pressure gas switch, connected to a refrigerant circuit, to increase the volume of cooling air for sending air to the conditioning unit or the compressor especially whereby the temperature rise of the compressor itself as well as the rise of the high pressure of the refrigerant circuit are restrained and the continuous cold-keeping operation of the refrigerating machine under an overload is permitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-cooling condensing unit for a showcase with a built-in refrigerator, and more particularly to a control system for the air-cooling cooling.

[0002]

2. Description of the Related Art As a freezing and refrigerating open showcase, a showcase with a built-in refrigerator in which an air-cooling condensing unit of a refrigerator is incorporated in a base of a case body is well known. Here, the air-cooled condensing unit has an electric compressor and an air-cooled condenser with a cooling fan arranged side by side inside a base provided on the floor side of the case body of the showcase, and the base is blown during cool operation. The outside air sucked into the base from the front grill on the front side as a body is ventilated to the condenser to condense the refrigerant, and the exhaust cools the electric compressors lined up in the rear. I'm trying to exhaust to one side.

[0003]

As is well known, the refrigerating capacity characteristics of the air-cooling condensing unit described above are the specifications (rated output) of the electric compressor, and the heat radiation amount during operation and the condensation with the cooling fan. It depends on the balance with the heat dissipation capacity of the vessel. Further, the condensing unit is generally equipped with a high pressure switch as a protection means for the electric compressor, and when the high pressure of the refrigerant circuit exceeds the set value of the high pressure switch for some reason, the operation of the compressor is stopped. I am trying.

In this case, in the case where the electric compressor of the standard specification selected based on the required refrigerating capacity is used, the temperature inside the store where the showcase is installed becomes higher than the ambient condition defined by the specification of the showcase. When operating in an overload condition such as this, the temperature of the refrigerator and the high pressure of the refrigerant circuit rise excessively with it, and if the high pressure rises above the set value of the high pressure switch described above, the refrigerator is protected. Therefore, the switch operates and the operation of the refrigerator is stopped.

As described above, if the refrigerator is stopped each time due to the overload operation during the cold insulation operation, the product temperature of the product displayed in the showcase rises and the quality is impaired. On the other hand, as a measure against such overload operation, a fan control method is known in which a cooling fan attached to the condenser is switched to high-speed operation in accordance with an increase in ambient temperature to enhance the condensation capacity of the condenser. However, even if the number of rotations of the cooling fan attached to the condenser is increased, the exhaust heat is actually trapped inside the showcase base, and the heat generated from the refrigerator is effectively exhausted to the outside of the case. It is quite difficult. Therefore, in order to prevent the refrigerator from stopping due to overload operation,
It is conceivable to adopt a refrigerator whose refrigeration capacity is one rank higher in advance, but if a refrigerator with a higher rank is used, that price will naturally be added and the cost of the showcase will increase.

The present invention has been made in view of the above points, and a refrigerator having a high load resistance capable of continuously performing cold storage operation even when overloaded without increasing the capacity of the refrigerator itself. It is to provide an air-cooled condensing unit for a built-in showcase.

[0007]

In order to achieve the above object, in a condensing unit of the present invention, an exhaust fan disposed behind an electric compressor, and the exhaust fan are operated under an overload condition of a refrigerator. It shall be provided with a control means. Here, as the control means of the exhaust fan, a high pressure switch connected to the high pressure side refrigerant circuit of the refrigerator is used, and the exhaust fan is operated under the condition that the high pressure side pressure of the refrigerant circuit becomes equal to or higher than the set value of the high pressure pressure switch. It is better to drive the car. In this case, the operating pressure of the high pressure switch is set to a value slightly lower than the set value of the protective high pressure switch for the electric compressor.

[0008]

With the above construction, the ambient temperature rises during the cold-keeping operation of the showcase, causing an overload operation, and the high pressure side pressure of the refrigerant circuit of the refrigerator is the set value of the high pressure switch for the exhaust fan. When the temperature rises above (however, it is lower than the set value of the high pressure switch for protecting the refrigerator), the high pressure switch operates without delay in response and the exhaust fan starts,
Helps the hot air in the base of the showcase with built-in condensing unit to be expelled quickly out of the case. Therefore, the air volume of the cooling air flowing around the refrigerator is increased, and the air cooling capacity for the refrigerator is increased, whereby the temperature of the refrigerator itself and the pressure on the high-pressure side of the refrigerant circuit are prevented from rising excessively, and the refrigerator is cooled. It is possible to continue the cold-storage operation without unnecessarily stopping. If the overload operating condition is eliminated due to a decrease in ambient temperature and the pressure on the high-pressure side of the refrigerant circuit falls below the set value of the high-pressure pressure switch, the switch will return and the exhaust fan will stop, resulting in steady operation. Return to.

[0009]

Embodiments of the present invention will be described below with reference to FIGS. First, in FIG. 1, 1 is a case body of a flat open showcase, 2 is a cool air circulation air passage inside the compartment defined between an outer box and an inner box of the case body, 3 is an evaporator of a refrigerator, 4 Is a blower fan for circulating cold air, and inside the base 1a provided on the floor side of the case body 1, an air-cooled condenser 5, an electric compressor 6, and a combination of a cooling fan 5a in order from the front, and the present invention. Thus, the exhaust fan 7 additionally installed is housed and arranged to form an air-cooling condensing unit of the refrigerator. Reference numeral 8 is a front panel of the case body having an opening for an outside air suction port communicating with the inside of the base 1a.

On the other hand, FIG. 2 is a basic operation control circuit diagram of the condensing unit. In the figure, 9 is an operation switch connected to the power source side, and 10 is a protective connection connected to the motor 6a of the electric compressor 6. The high pressure switch (contact b) 11 is a high pressure switch for operation control (contact a) connected to the motor 7a of the exhaust fan. The high-pressure pressure switches 10 and 11 are branched and connected to the high-pressure side refrigerant circuit of the refrigerator (the line of the refrigerant liquid discharged from the condenser).
When the high-side pressure rises above the set value, the switch will respond. Here, the high pressure switch 11 connected to the motor circuit of the exhaust fan 7 is set to a pressure value slightly lower than the set value of the high pressure switch 10 connected to the compressor motor.

With such a configuration, the pressure on the high-pressure side of the refrigerant circuit is equal to or lower than the set value of the high-pressure pressure switch 11 in the normal cold-keeping operation state, and the refrigerator operates while the exhaust fan 7 is stopped to operate the inside of the showcase. It's kept cool. On the other hand, the refrigerator is overloaded due to an increase in the ambient temperature of the showcase, and the temperature of the compressor 6 and the pressure on the high-pressure side of the refrigerant circuit rise, but exceed the set value of the high-pressure pressure switch 11. Then, the high pressure switch 11 is turned on (a contact is turned on).
Then, the exhaust fan 7 is started. When the exhaust fan 11 operates, the cooling fan 5a of the condenser 5
In cooperation with the above, the amount of air that flows through the base 1a is increased, and the hot air trapped inside the base 1a of the case main body is sucked and quickly exhausted to the back side of the showcase.

As a result, the air cooling capacity for the compressor 6 is enhanced, and the temperature of the compressor itself and the pressure on the high pressure side of the refrigerant circuit are prevented from further increasing. Moreover, in this operating state, the high-pressure side pressure of the refrigerant circuit is equal to or lower than the set value of the high-pressure pressure switch 10, so that the compressor 6 continues to rotate without stopping and continues the cold insulation operation of the showcase. Then, when the overload operation is eliminated due to a decrease in the ambient temperature, the high pressure switch 11 is restored, the exhaust fan 7 is stopped, and the normal operation is resumed. If the high-pressure side pressure of the refrigerant circuit further rises despite the fact that the exhaust fan 7 is operating due to some abnormality, the high-pressure pressure switch 10 operates to stop the operation of the refrigerator.

[0013]

As described above, according to the present invention, when the refrigerator is in an overloaded operation state due to an increase in ambient temperature or the like, an exhaust fan additionally provided in the condensing unit is activated to start ventilation air. To enhance the air cooling capacity for the electric compressor. As a result, the temperature of the compressor and the pressure on the high-pressure side of the refrigerant circuit are prevented from rising excessively, and the cold storage operation of the refrigerator can be continued. In other words, by additionally installing an inexpensive exhaust fan, the showcase can be continued without stopping the operation of the refrigerator even if it is overloaded, without using the standard compressor without upgrading the refrigerator. Can be kept cool. Moreover, by using a high-pressure switch as the operation control means of the exhaust fan, the exhaust fan can be accurately turned on and off without delay in response when overloaded as compared with a thermostat, etc. The advantage is that the fan can be stopped to prevent excessive power consumption.

[Brief description of drawings]

FIG. 1 is a sectional view showing the construction of a showcase with a built-in refrigerator according to an embodiment of the present invention.

FIG. 2 is an operation control circuit diagram of the condensing unit in FIG.

[Explanation of symbols]

1 Show Case Case 1a Base 5 Air-cooled Condenser 5a Cooling Fan 6 Electric Compressor 7 Exhaust Fan 9 Operation Switch 10 High Pressure Switch (for Compressor) 11 High Pressure Switch (Exhaust Fan Operation Control Means)

Claims (3)

[Claims] 1. An air-cooled condensing unit for a showcase with a built-in refrigerator, wherein an air-cooled condenser with a cooling fan and an electric compressor are arranged side by side in a showcase base and are installed behind the electric compressor. A condensing unit for a showcase with a built-in refrigerator, comprising: an exhaust fan disposed in the refrigerator; and control means for operating the exhaust fan when the refrigerator is overloaded. 2. The air-cooling condensing unit according to claim 1, wherein the control means of the exhaust fan is a high pressure pressure switch connected to a high pressure side refrigerant circuit of the refrigerator, and the high pressure side pressure of the refrigerant circuit is the high pressure side pressure switch. An air-cooled condensing unit for a showcase with a built-in refrigerator, which operates the exhaust fan under the condition where it exceeds the set value. 3. An air-cooled condensing unit according to claim 2, wherein the operating pressure of the high pressure switch is set to a value slightly lower than the set value of the protective high pressure switch for the electric compressor. Built-in showcase air-cooled condensing unit.