Refrigerator

Details Refrigerator Refrigerator

2000-11-28

2002-06-04

Doerrler, William C. (Department: 3744)

Refrigeration

Automatic control

Time or program actuator

C062S174000

Reexamination Certificate

active

06397608

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a refrigerator provided with an evaporator for a refrigerator compartment and an evaporator for a freezer compartment.
BACKGROUND ART
A refrigerator provided with a refrigerator compartment and a freezer compartment, each compartment is equipped with a dedicated evaporator in some refrigerators of recent years. These refrigerators have a freezing cycle, as shown in FIG.
13
.
In the freezing cycle
100
of
FIG. 13
, a condenser
103
is connected to the downstream side of a compressor
102
, which is divided at its downstream into two branches. To one branch, there are connected a refrigerator compartment change-over valve (as will be abbreviated into the “R-valve”)
104
, a refrigerator compartment capillary tube (as will be abbreviated into the “R-capi”)
106
and a refrigerator compartment evaporator (as will be abbreviated into the “R-eva”)
108
. To the other branch, there are connected a freezer compartment change-over valve (as will be abbreviated into the “F-valve”)
110
, a freezer compartment capillary tube (as will be abbreviated into the “F-capi”)
112
, a freezer compartment evaporator (as will be abbreviated into the “F-eva”)
114
and a check valve
116
. Moreover, the conduits from the check-valve
116
and the R-eva
108
circulate through the compressor
102
.
On the other hand, an R-fan
118
is provided for feeding the air cooled in the R-eva
108
to the refrigerator compartment, and the F-eva
114
is equipped with an F-fan
120
.
In the aforementioned freezing cycle
100
, the prior art control method will be described with reference to FIG.
14
.
In this control method, a refrigerating run (as will be abbreviated into the “R-mode”) for cooling the refrigerator compartment and a freezing run (as will be abbreviated into the “F-mode”) for cooling the freezer compartment are alternately carried out. When the refrigerator compartment reaches a predetermined temperature, specifically, the R-valve
104
is opened, but the F-valve
110
is opened to feed the refrigerant to the F-eva
114
thereby to establish the F-mode. When the freezer compartment reaches a predetermined temperature in the F-mode, on the other hand, the F-valve
110
is closed, but the R-valve
104
is opened to feed the refrigerant to the R-eva
108
thereby to establish the R-mode.
SUMMARY OF THE INVENTION
Here, the R-eva
108
and the F-eva
114
are different in evaporation temperature and in the calorie of evaporation enthalpy. If both the R-eva
108
and the F-eva
114
have a necessary cooling calorie of 40 W, therefore, the refrigerant flow rate in the R-eva
108
is twice as high as that of the F-eva
114
because of the difference in the calorie of the evaporation enthalpy. In other words, when the evaporation temperature rises from a low level to a high level, the necessary refrigerant flow rate is raised by the difference in the specific suction capacity of the compressor
102
.
This difference in the refrigerant circulation rate between the R-eva
108
and the F-eva
114
causes the delay in the refrigerant behaviors at the transition from the F-mode to the R-mode. For the first reason, the refrigerant flowing at rate of 1 in the F-mode has to flow at a rate of 2 when the mode is switched to the R-mode. For the second reason, the compression ratio of the compressor
102
is high in the F-mode but falls in the R-mode, so that the refrigerant is reluctant to flow into the R-eva
108
due to the difference in the compression ratio.
Moreover, the aforementioned delay in the refrigerant behaviors triggers to establish the state, in which anywhere but the entrance portion of the R-eva
108
is not cooled, as shown in FIG.
13
. There arises a problem that the exit or its vicinity is not cooled to a necessary temperature so that the sufficient cooling capacity is not exhibited. This problem affects the cooling capacity adversely.
On the other hand, the refrigerant, as has been stagnant in the F-eva
114
, cannot flow to the compressor
102
when in the R-mode at the high pressure. As a result, the refrigerant circulation is so lessened as cannot be adjusted. Therefore, the flow rate of the refrigerant circulation in the freezing cycle
100
changes for each run. Moreover, this change causes a more delay in the refrigerant behaviors.
From the problems thus far described, there arise problems that the refrigerant circulation cannot be correctly controlled, and that the cooling ability cannot be correctly controlled.
In view of the foregoing problems, therefore, the invention contemplates to provide a refrigerator which can control the refrigerant circulation correctly and can reduce the delay in the refrigerant behaviors.
DISCLOSURE OF THE INVENTION
According to the invention, there is provided a refrigerator comprising: a compressor and a condenser connected in the recited order; an evaporator for a refrigerator compartment and an evaporator for a freezer compartment both connected in parallel to the downstream side of the condenser, and switching unit interposed between the condenser and the two evaporators for switching the passage for a refrigerant from the condenser, between the refrigerator compartment evaporator and the freezer compartment evaporator; and a condenser fan for cooling the condenser, a cold air circulation fan for the refrigerator compartment for blowing the cold wind of the refrigerator compartment evaporator to the refrigerator compartment, and a cold wind circulation fan for a refrigerator compartment for blowing the cold air of the refrigerator compartment evaporator to the freezer compartment, whereby a refrigerating run for cooling the refrigerator compartment by feeding the refrigerant to the refrigerator compartment evaporator and a freezing run for cooling the freezer compartment by feeding the refrigerant to the freezer compartment evaporator can be individually executed by switching the passage of the refrigerant by the switching unit, wherein at the end of the freezing run, a refrigerant recovery run for recovering the refrigerant from the refrigerator compartment evaporator and feeding it to the condenser is performed by running the compressor while blocking the refrigerant to flow to the freezer compartment evaporator with the switching unit and by running the condenser fan; and after this refrigerant recovery run, the refrigerating run is performed by switching the switching unit to feed the refrigerant only to the refrigerator compartment evaporator.
In a refrigerator according to the invention, after a predetermined time from the start of the refrigerant recovery run, the refrigerating run is performed by switching the switching unit to feed the refrigerant only to the refrigerator compartment evaporator.
In a refrigerator according to the invention, after the temperature of the freezer compartment evaporator reaches a predetermined level after the start of the refrigerant recovery run, the refrigerating run is performed by switching the switching unit to feed the refrigerant only to the refrigerator compartment evaporator.
In a refrigerator according to the invention, after the refrigerating run was performed by switching the switching unit to feed the refrigerant only to the refrigerator compartment evaporator, the cold air circulation fan for the refrigerator compartment is run when the temperature of the refrigerator compartment evaporator falls to a set level.
In a refrigerator according to the invention, when the compressor is to be stopped from the freezing run or the refrigerating run, a stop preparatory run for recovering the refrigerant from the freezer compartment evaporator or the refrigerator compartment evaporator to feed the refrigerant to the condenser is performed by running the compressor while switching the switching unit to block the refrigerant to be fed to the freezer compartment evaporator or the refrigerator compartment evaporator, and by running the condenser fan at a low speed, and after the stop preparatory run, the compressor and the condenser fan are stopped while the ref

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