JPS596374Y2 - Freezer car refrigeration system - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a refrigeration system for a refrigerated vehicle equipped with a freezer.

Conventionally, refrigerated vehicles equipped with a freezer for storing items that need to be frozen, such as fresh fish and vegetables, have a single compressor unit that combines a cooler unit for internal refrigeration and a cabin cooler unit for cooling the cabin where the driver is. It is connected to the capacitor and operates.

In particular, in this refrigeration system, the temperature is sensed by a thermostat installed inside the refrigerator or the cabin, and the temperature sensing operates the on-off valve to prevent the refrigerant from flowing into each cooler unit for cooling the compartment. In addition, a pressure regulating valve is placed near the outlet of each cooler unit, so that when one unit stops operating, all of the refrigerant in the refrigeration circuit flows in, preventing overcooling of the operating unit. There is.

Therefore, if the interior cooler unit stops operating and the cabin cooler unit is in operation, the pressure regulating valve operates to prevent all refrigerant from circulating in the refrigeration circuit, and the compressor suction There is a risk of negative pressure on the compressor side and overloading the compressor itself.

Particularly when the outside air temperature is low, the above-mentioned load condition on the suction side is likely to occur.

The present invention has been made based on this drawback, and an object of the present invention is to provide a refrigeration system for a freezer that operates smoothly without generating negative pressure on the suction side of the compressor.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the refrigeration system for a refrigerated vehicle according to the present invention will be described with reference to the drawings.

The refrigerator car 1 shown in FIG. 1 has a cabin 2 at the front and a freezer 3 at the rear. A cabin cooler unit is installed in the lower area of the cabin 2, and a cooler unit for the cabin is installed in the upper end area of the freezer 3. An internal cooler unit 5 is attached to each.

Both cooler units 4 and 5 are connected to a single compressor 6 which is connected to an engine (not shown) via a clutch, and a single condenser unit 7 mounted on the cabin, forming a so-called refrigeration cycle. It is supposed to be done.

In other words, the refrigeration circuit of this refrigeration system, as shown in FIG.
and a condenser unit are connected by a conduit 8.

The condenser unit 7 includes a heat exchanger S connected to the discharge side of the compressor 6 by a conduit 8, a fan device 10, and a liquid tank 11, and converts the high temperature and high pressure refrigerant discharged from the compressor 6 into a low temperature and high pressure It is designed to become something.

Next, the internal cooler unit 5 is connected to the condenser unit 7 by a conduit 8 via an electromagnetic on-off valve 12, and includes a dryer 13, an expansion valve 14, a heat exchanger 15, a fan device 16, and a pressure regulating valve 17. The inside of the refrigerator is cooled by exchanging heat between the low-temperature, low-pressure refrigerant that is adiabatically expanded by the expansion valve 14 and the air inside the refrigerator.

Further, the cabin cooler unit 4 is installed in parallel with the interior cooler unit 5, and has a conduit 8 for guiding the refrigerant discharged from the condenser unit 7.
It is connected via an electromagnetic on-off valve 18 and includes an expansion valve 19, a heat exchanger 20, a fan device 21, and an evaporation pressure regulating valve 22. In particular, in the refrigeration system according to the present invention, this pressure regulating valve 22 is An electric evaporation on-off valve 23 is provided in parallel.

This electromagnetic on-off valve 23 is for preventing the suction circuit of the compressor 6 from becoming negative pressure when the pressure regulating valve 22 is closed.

Next, the effect will be explained.

When a thermostat (not shown) installed in the cabin 2 or the freezer 3 senses that the temperature has dropped below a set temperature, this sensing signal is sent to the compressor 6, which is activated.

Due to the operation of the compressor 6, the refrigerant in the refrigeration circuit is sucked in from the suction side, compressed, becomes high temperature and high pressure, and is discharged from the discharge side.

In addition, either one or both of the electromagnetic on-off valves 12 and 18 are opened by the sensing signal, and the discharged refrigerant passes through the condenser unit 7 and then is transferred to either the internal cooler unit 5 or the cabin cooler unit 4. Applies to one or both.

That is, as is well known, the refrigerant is adiabatically expanded to become a low-temperature, low-pressure refrigerant, which exchanges heat with the air inside the refrigerator or the air inside the cabin to cool each room.

When the temperature of this cabin 2 falls below a predetermined temperature, the electromagnetic on-off valve 18 is closed by the thermostat, and the refrigerant flows only to the internal cooler unit 5 side.
If both temperatures fall below a predetermined temperature, the thermostat inside the refrigerator will also operate and the compressor 6 will stop.

However, when the temperature of the cabin 2 rises above the predetermined temperature again, the thermostat operates and the compressor 6 starts again, but in this case, all the refrigerant in this refrigeration circuit flows to the cabin cooler unit 4, causing the inside of the cabin to become overheated. Due to cooling, the pressure regulating valve 22 automatically closes.

On the other hand, since the thermostat inside the freezer is designed to open the electromagnetic on-off valve 23 of the cabin cooler unit 4 when the inside temperature reaches a predetermined temperature, the compressor can also be shut off by closing the pressure regulating valve 22. No. 6 suction side circuit does not become negative pressure.

In the embodiment described above, the electromagnetic on-off valve 23 is provided in the bypass circuit of the cabin cooler unit 4, and the valve is opened by the thermostat of the internal cooler unit 5. However, when the outside air temperature falls below a certain level, When the internal cooler unit stops operating, the electromagnetic on-off valve 23
It goes without saying that the structure may be configured such that the area is open.

As described above, according to the refrigeration system for a refrigerated car according to the present invention, in the refrigeration system for a refrigerated car equipped with a cabin cooler unit and an internal cooler unit, the refrigeration system is installed near the outlet of the cabin cooler unit. In parallel with the pressure regulating valve, an electromagnetic opening/closing valve was provided that is operated to open or close by a thermostat that senses the internal temperature or outside temperature. This is extremely practical, as the on-off valve is opened and no negative pressure is created on the suction side of the compressor, and the above-mentioned negative pressure condition does not occur even when the cabin cooler unit is operating, especially when the outside temperature is low. It has the desired effect.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a refrigeration system for a refrigerated vehicle, and FIG. 2 is a refrigeration circuit diagram showing an embodiment of the refrigeration system for a refrigerated vehicle according to the present invention. 1... Refrigerator truck, 2... Cabin, 3.
... Freezer, 4 ... Cabin cooler unit, 5 ... Inner cooler unit, 6 ...
... Compressor, 7 ... Capacitor unit, 12, 18 ... Solenoid shut-off valve, 22 ...
...Pressure regulating valve, 23...Solenoid opening/closing valve.

Claims (1)

[Scope of utility model registration request] Thermostats installed in the cabin and freezer detect each room temperature, and based on this detection signal, on-off valves installed in each circuit apply refrigerant from the compressor to the cabin cooler unit and the interior cooler unit. In the refrigeration system for a refrigerated vehicle, the pressure inside the cabin cooler unit is adjusted by opening and closing the air cooler unit to adjust the amount of refrigerant flowing through each cooler unit by a pressure regulating valve provided in each cooler unit. A bypass circuit is installed in parallel to the regulating valve, and during this circuit, when the refrigerator unit cooler unit stops operating, or when the outside temperature drops below a certain level and the refrigerator unit cooler unit stops operating. A refrigeration system for a refrigerated vehicle, characterized in that it includes an electromagnetic on-off valve that is opened when the vehicle is stopped.