Refrigeration – Refrigeration producer – Compressor-condenser-evaporator circuit
Reexamination Certificate
2001-04-13
2003-04-22
Wayner, William (Department: 3744)
Refrigeration
Refrigeration producer
Compressor-condenser-evaporator circuit
C165S147000, C165S150000
Reexamination Certificate
active
06550273
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an air conditioner using a flammable fluid as a refrigerant, and more particularly, to an air conditioner using a flammable refrigerant, especially, HC based refrigerant such as propane, isobutane and the like as a refrigerant.
BACKGROUND TECHNIQUE
HCFC based refrigerants such as R22, which are stable components and composed of hydrogen, chlorine, fluorine and carbon are currently utilized in an air conditioner.
However, HCFC refrigerants rise into the stratosphere and decompose ozone, leading to the destruction of the ozone layer.
In recent years, HFC refrigerants begin to be utilized as alternative refrigerants of HCFCs, but these HFC refrigerants have the nature for facilitating the global warming.
Therefore, a study is started to employ HC refrigerant which does not destroy the ozone layer or largely affect the global warming.
However, since this HC refrigerant is flammable, it is necessary to prevent explosion or ignition so as to ensure the safety.
As a method for preventing the explosion or ignition when HC refrigerant is used, it is proposed to isolate, move away or not to use an ignition source (Japanese Patent Applications Laid-open No.H7-55267 and No.H8-61702, for example).
On the other hand, as another method for preventing the explosion or ignition when HC based refrigerant is used, it is proposed to make the refrigerant itself into a non-flammable refrigerant (Japanese Patent Application Laid-open No.H9-59609), and it is proposed to reduce the amount of refrigerant (Japanese Patent Applications Laid-open No.H8-170859 and No.H8-170860) in the mixture.
Here, the conventional techniques (Japanese Patent Applications Laid-open No.H8-170859 and No.H8-170860) for reducing the amount refrigerant to be used will be explained in more detail.
Japanese Patent Application Laid-open No. H8-170859 and No. H8-170860 relate to a refrigerator. In order to reduce the amount of refrigerant, it is proposed: to provide a heat pipe in addition to a refrigeration cycle and to use non-flammable refrigerant for the heat pipe; to provide a refrigerant tube for heat exchangers in the compartment of the refrigerator separately from a refrigerant tube for an evaporator and to use non-flammable refrigerant for the heat pipe; to change the number of paths upstream and downstream of the evaporator or a condenser; and the like.
First, the method for preventing the explosion or ignition by isolating, moving away or not using the ignition source is very effective if the air conditioner is used alone. However, an air conditioner is used in a closed space, and other equipments may have the ignition source. Therefore, even if safety as an air conditioner may be enhanced, it can not be said that the safety is always ensured depending upon a using state.
The method for preventing the explosion or ignition by making the refrigerant itself into a non-flammable refrigerant does not have the above problem, and it can be said that safety is ensured in any of using states.
However, it is not easy to make the flammable refrigerant itself into a non-flammable refrigerant while achieving a required level of refrigerating performance without adversely affecting the global environment such as decreasing of ozone layer and global warming.
The method for reducing the refrigerant amount may not always prevent the explosion or ignition perfectly, but it contributes to effective utilization of resources. Further, even if a harmful influence may be found in the future, if the amount of refrigerant is small, such a harmful influence can be suppressed to the minimum.
Thereupon, it is an object of the present invention to technically reduce a risk of explosion or ignition and to enhance the safety by reducing an amount of refrigerant to be charged in the refrigeration cycle.
Meanwhile, if the amount of refrigerant to be charged in the refrigeration cycle is reduced without changing other conditions, since the circulation amount of refrigerant is reduced, there is a problem that cooling capacity is decreased. Further, if the compression volume is increased or the revolution number of the compressor is increased so as to prevent the cooling capacity from being decreased, there is a problem that power input is increased and the efficiency is decreased.
Thereupon, a primary object of the invention is to reduce the amount of refrigerant to be charged in the refrigeration cycle without decreasing the capacity and efficiency.
Further, a secondary object is to reduce the amount of refrigerant to be charged in the refrigeration cycle without decreasing the capacity if R290 is used as a refrigerant or mainly used as the refrigerant mixtures, while obtaining substantially the same efficiency as the case in which R22 is used as refrigerant.
DISCLOSURE OF THE INVENTION
An air conditioner using a flammable refrigerant according to a first aspect of the present invention, an inner diameter of a liquid-side connecting pipe is smaller than 42.5% of an inner diameter of a gas-side connecting pipe.
According to a second aspect of the invention, an inner diameter of the liquid-side connecting pipe is 1 mm to 3.36 mm.
According to a third aspect, the liquid-side connecting pipe is a capillary tube.
An air conditioner using a flammable refrigerant according to a fourth aspect, an inner diameter of a liquid-side tube of the outdoor unit is smaller than 42.5% of an inner diameter of a gas-side tube of the outdoor unit.
An air conditioner using a flammable refrigerant according to a fifth aspect an inner diameter of a liquid-side tube of the indoor unit is smaller than 42.5% of an inner diameter of a gas-side tube of the indoor unit.
According to a sixth aspect, an inner diameter of the liquid-side tube of the fourth or fifth aspect is 1 mm to 3.36 mm.
According to a seventh aspect, the liquid-side tube of the fourth or fifth aspect is a capillary tube.
A refrigeration cycle using a flammable refrigerant according to an eighth aspect, an inner diameter of a liquid-side tube of the tube is smaller than 42.5% of an inner diameter of a gas-side tube.
According to a ninth aspect, an inner diameter of the liquid-side tube is 1 mm to 3.36 mm.
A refrigeration cycle using a flammable refrigerant according to a tenth aspect, a liquid-side tube among the tubes is a capillary tube.
An air conditioner using a flammable refrigerant according to an eleventh aspect, an inner diameter of a liquid-side connecting pipe among the connecting pipes is 1 mm to 3.36 mm.
A refrigeration cycle using a flammable refrigerant according to a twelfth aspect, an inner diameter of a liquid-side tube among the tubes is 1 mm to 3.36 mm.
According to the first to twelfth aspects of the present invention, by reducing a diameter of the tube in which a liquid refrigerant flows in the air conditioner or the refrigeration cycle, it is possible to reduce the amount of refrigerant to be charged without decreasing the capacity and the efficiency.
An air conditioner using a flammable refrigerant according to a thirteenth aspect, a liquid-side connecting pipe is a capillary tube, and the expansion device is an expansion valve having a variable flow rate.
According to this aspect, an opening of the expansion valve can be adjusted by the expansion valve in accordance with a length or diameter of the liquid-side connecting pipe or a state of a refrigeration cycle. Therefore, it is possible to reduce the diameter of the liquid-side connecting pipe, and since the throttle degree can be adjusted by the expansion valve, the diameter can be reduced appropriately, and it is possible to reduce the amount of refrigerant to be charged without decreasing the capacity.
An air conditioner using a flammable refrigerant according to a fourteenth aspect, not only the liquid-side tube of the outdoor unit, but also the liquid-side tube of the indoor unit is provided with an expansion device. Since the liquid-side tube of the indoor unit is also provided with the expansion device in this manner, the refrigerant in the liquid-side connecting pipe can assume a two
Fujitaka Akira
Kobayashi Yoshinori
Tachigori Riko
Armstrong Westerman & Hattori, LLP
Wayner William
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