Cooling apparatus

Abstract

A cooling apparatus which stably cools a target. The cooling apparatus includes a primary circuit that has a first heat exchanging section which is provided at a heat exchanger, and vaporizes a liquid-phase primary coolant to be a gas-phase primary coolant, and a condenser which condenses the gas-phase primary coolant to be the liquid-phase primary coolant, and lets the liquid-phase primary coolant flow to the first heat exchanging section from the condenser through a liquid piping and lets the gas-phase primary coolant flow to the condenser from the first heat exchanging section through a gas piping. The cooling apparatus further includes a secondary circuit having a second heat exchanging section, an expansion valve, an evaporator, and a compressor connected together by a coolant piping.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a cooling apparatus for use in a refrigerator, a freezer, an ice making machine, an air-conditioning system and the like.[0003]2. Description of the Related Art[0004]As a cooling apparatus for use in a refrigerator, a freezer, an ice making machine, an air-conditioning system and the like, a so-called remote condenser type (also called separate type) cooling apparatus 10 having a compressor CM and an evaporator EP disposed in a main body unit 12 arranged indoor and having a condenser CD disposed in an external unit 14 arranged outdoor has been proposed (see, for example, Japanese Patent Application Laid-Open No. H8-200746), as shown in FIG. 6. The cooling apparatus 10 of this type has a disadvantage that the provision of the condenser CD which is a heat discharging part outdoor can suppress a temperature rise in the main body unit 12.SUMMARY OF THE INVENTION[0005]In an environment where ...

AI Technical Summary

Benefits of technology

[0006]As a solution to the problem, the cooling apparatus 10 has a condensing pressure regulating valve 20 provided in the cooling circuit 11 to regulate the flow rate of the coolant circulating into the cooling circuit 11, thereby suppressing a pressure drop on the high pressure side in the cooling circuit 11. Specifically, the cooling apparatus 10 is provided with a bypass pipe 18 bypassing the condenser CD between the coolant piping 16 which connects the compressor CM to the condenser CD, and the coolant piping 16 which connects the condenser CD to the expansion valve EV, and the condensing pressure regulating valve 20 is interposed at the bypass pipe 18. When the outside temperature becomes low, the condensing pressure regulating valve 20 of the cooling apparatus 10 adjusts the coolant so that the coolant stays in the condenser CD to reduce the area of heat exchange between the coolant and outside air in the condenser CD, thereby reducing the amount of heat discharge from the condenser CD and holding the pressure on the high pressure side of the cooling circuit 11. However, the adjustment by the condensing pressure regulating valve 20 needs to increase the amount of the coolant to be filled in the cooling circuit 11 in order to secure the amount of the coolant staying in the condenser CD when the outside temperature drops. As the amount of the coolant to be filled in the cooling circuit 11 increases, a lot of the coolant sleeps in the compressor CM when the compressor CM is stopped, so that when the compressor CM is activated, the oil is likely to be discharged by oil foaming or the like, and the viscosity of the lubricant to be filled in the compressor CM drops, causing wearing or the like of the operational parts of the compressor CM. This may result in malfunction of the compressor CM. Further, it is necessary to provide a liquid receiver R in the cooling, apparatus 10 to store a large amount of coolant unnecessary when the outside temperature is high, thus complicating the configuration and leading to a cost increase.

[0007]Another problem is that when the cooling circuit 11 is provided with a bypass circuit 22 which directly supplies the coolant to the evaporator EP from the compressor CM to execute deicing or defrosting with a hot gas, a part of the hot gas may flow into the condenser CD to be liquefied because the condenser CD is connected to the outlet side of the compressor CM. It is pointed out that when the coolant stays in the compressor CM this way, the amount of the coolant circulating in the cooling circuit 11 decreases, reducing the hot-gas based deicing performance and lowering the ice making efficiency. Since the adjustment with the condensing pressure regulating valve 20 actively lets the coolant stay in the condenser CD when the outside temperature drops, as mentioned above, the hot-gas based deicing performance is impaired significantly in the cooling apparatus 10 which supplies the hot gas to the evaporator EP through the bypass circuit 22.

[0013]Even when the ambient temperature changes, the cooling apparatus according to the present invention can suppress the influence of the temperature change on the secondary circuit, so that the secondary circuit can stably cool a target object.

Problems solved by technology

That is, in the cooling circuit 11, when a pressure on the high pressure side falls to nullify a difference between the pressure on the high pressure side and the pressure on the low pressure side from the outlet side of the expansion valve EV to the inlet side of the compressor CM, cooling of a target object by the evaporator EP cannot be controlled well, excessively cooling the target object.

The remote condenser type cooling apparatus 10 lacks the stability of the cooling function with respect to a change in outside temperature.

As the amount of the coolant to be filled in the cooling circuit 11 increases, a lot of the coolant sleeps in the compressor CM when the compressor CM is stopped, so that when the compressor CM is activated, the oil is likely to be discharged by oil foaming or the like, and the viscosity of the lubricant to be filled in the compressor CM drops, causing wearing or the like of the operational parts of the compressor CM.

This may result in malfunction of the compressor CM.

Further, it is necessary to provide a liquid receiver R in the cooling, apparatus 10 to store a large amount of coolant unnecessary when the outside temperature is high, thus complicating the configuration and leading to a cost increase.

Another problem is that when the cooling circuit 11 is provided with a bypass circuit 22 which directly supplies the coolant to the evaporator EP from the compressor CM to execute deicing or defrosting with a hot gas, a part of the hot gas may flow into the condenser CD to be liquefied because the condenser CD is connected to the outlet side of the compressor CM.

It is pointed out that when the coolant stays in the compressor CM this way, the amount of the coolant circulating in the cooling circuit 11 decreases, reducing the hot-gas based deicing performance and lowering the ice making efficiency.

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