JP2001263832A - Refrigerating cycle of refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating cycle of a refrigerant capable of being started without necessity of a large torque without generating a difference of pressures between an inlet and an outlet of a compressor by maintaining separate high and low pressures of a condenser and an evaporator when the compressor is stopped. SOLUTION: The compressor, the condenser, a capillary tube, and the evaporator are sequentially connected. A four-way valve is provided between the condenser and the tube.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating cycle in a refrigerator.

[0002]

2. Description of the Related Art FIG.
FIG. 7 is a diagram illustrating a refrigerant flow path of a refrigeration cycle of a refrigerator in a first conventional example disclosed in Japanese Patent No. 7 (No. 7). FIG. 4 is a graph showing pressure changes at various points in the refrigeration cycle during operation of FIG.

As shown in FIG. 3, a refrigerating cycle includes a compressor 1, a condenser 2, a dryer 3, a capillary tube 4, and an evaporator 5.
Are connected in order. The graph of, in FIG.
The pressure change measured at the position indicated by, is shown. During the refrigeration cycle operation (comp on), the pressure becomes high, and when the refrigerant becomes low pressure through the capillary tube 4, it becomes low. On the other hand, when the temperature in the refrigerator is cooled to a predetermined temperature and the compressor 1 is stopped (compressed off), the refrigerant on the high pressure side of the condenser 2 flows into the evaporator 5 through the capillary tube 4, and the pressures on the high pressure side and the low pressure side are reduced. Balance. At this time, the refrigerant does not flow from the high pressure side to the low pressure side after passing through the compressor 1.

However, when the refrigeration cycle is stopped (comp-off), the refrigerant on the high-pressure side flows into the evaporator 5, so that the temperature of the evaporator 5 rises and the temperature inside the refrigerator also rises. Had a problem that loss occurred.

Next, a second conventional example will be described. FIG.
FIG. 1 is a view showing a refrigerant flow path of a refrigeration cycle of a refrigerator in a second conventional example disclosed in, for example, Japanese Patent Application Laid-Open No. 11-132577 (a dew-proof pipe is not shown). FIG. 6 is a graph showing pressure changes at various points in the refrigeration cycle during operation of FIG.

As shown in FIG. 5, the refrigeration cycle is provided with a three-way valve 7, a bypass pipe (bypass pipe) 8, and a check valve 9, which are not provided in the first conventional example. The loss of the refrigeration cycle is prevented. FIG.
In the graph of,,,
3 shows the pressure change measured at the positions of. In FIG. 5, the refrigeration cycle includes a three-way valve 7 provided between the condenser 2 and the capillary tube 4, and a bypass pipe 8 connecting the three-way valve 7 and the compressor 1. Further, a check valve 9 is provided between the compressor 1 and the evaporator 5. During the operation of the refrigeration cycle, the three-way valve 7 allows the refrigerant to flow to the capillary tube 4.
This allows the refrigerant to flow to the bypass pipe 8.

Accordingly, when the refrigeration cycle is stopped, the refrigerant does not flow from the high pressure side to the low pressure side by the three-way valve 7,
Cycle loss can be reduced, and the differential pressure across the compressor 1 during startup is small, and the startup performance is good.

Another conventional example is disclosed in Japanese Patent Application Laid-Open No. 58-99.
No. 655, there is a description of a refrigeration cycle using a four-way valve.

[0009]

However, also in the second conventional example, the number of components such as the check valve 9 and the bypass pipe 8 from the three-way valve 7 is large and the cost is high. In addition, the bypass pipe 8 increases the noise, and the bypass pipe 8 is generally a capillary tube to suppress the transmission of vibration to the box. However, in the low-pressure shell that discharges the discharge gas directly to the refrigeration cycle, sludge is clogged. There was a problem.

Therefore, the present invention has been made to solve the above-mentioned problem, and a large torque is required without a pressure difference between the inlet and the outlet even when the compressor is stopped. The present invention provides an inexpensive, highly reliable, and silent refrigerator refrigeration cycle that can be started without any trouble, does not include a check valve, bypass, and the like.

[0011]

According to a first aspect of the present invention, there is provided a refrigerating cycle for a refrigerator, comprising a compressor, a condenser, a capillary, and an evaporator connected in this order, and a four-way switching valve between the condenser and the capillary and between the evaporator and the compressor. It is provided.

The refrigeration cycle of the refrigerator according to claim 2 is
The four-way valve communicates between the condenser outlet and the capillary inlet and between the evaporator outlet and the compressor inlet when the compressor is operating, and between the condenser outlet and the compressor inlet and between the evaporator outlet and the capillary inlet when the compressor is stopped. Is what you do.

The refrigeration cycle of the refrigerator according to claim 3 is
The four-way valve communicates between the condenser outlet and the capillary inlet and between the evaporator outlet and the compressor inlet during the defrosting operation.

[0014] The refrigeration cycle of the refrigerator according to claim 4 is as follows.
The compressor is a low-pressure shell compressor.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram showing a refrigeration cycle of a refrigerator according to Embodiment 1 of the present invention. In the figure, 1 is a low-pressure shell compressor, 2 is a condenser (condenser), 3 is a dryer, 4 is a capillary tube, 5 is an evaporator, and a refrigeration cycle is formed in this order. 6
Is a four-way valve provided between the dryer 3 and the capillary 4 and between the evaporator 5 and the compressor 1. The refrigerant flows in the direction of the arrow in the refrigeration cycle. The four-way valve 6 connects the inlet A to the dryer 3, the outlet B to the capillary tube 4, the inlet C to the evaporator 5, and the outlet D to the compressor 1. During the operation of the refrigeration cycle (compressor 1), A and B and C and D communicate with each other. While the refrigeration cycle (compressor 1) is stopped, A and D and B and C communicate with each other as shown in FIG. In addition, B and C may be connected or closed. As shown in FIG. 2, while the compressor is stopped, a closed circuit of a high pressure region provided with the compressor 1, the condenser 2, and the dryer 3 and a closed circuit of a low pressure region provided with the capillary tube 4 and the evaporator 5 are configured. . During the operation of the refrigeration cycle, a normal refrigeration cycle is formed, and a normal cooling operation can be performed. When the refrigeration cycle is stopped, high and low pressures are separated on the cycle, and high-pressure refrigerant is passed from the dryer to the compressor, so that the pressure difference between suction and discharge of the compressor can be reduced.

A dryer (DRYER) 3 is disposed between the condenser 2 and the capillary tube 4 to remove moisture and foreign matters of the refrigerant flowing into the capillary tube 4. The moisture is, for example, a moisture absorbing material called molecular sieve, and the foreign matter is absorbed by a filter. If the dryer 3 is arranged before the four-way valve 6, the four-way valve 6 does not require a filter for removing foreign matter.

When the compressor is a high-pressure shell, high-pressure gas flows back into the shell and the suction pipe when the compressor is stopped.
The pressure before and after the compressor is the same and is balanced. However, in the case of the low-pressure shell compressor 1, pressure cannot be balanced. Therefore, by adjusting the pressure balance before and after the compressor using the four-way valve 6 as in the present application, even if the compressor 1 is a low-pressure shell, compression is prevented. When the compressor 1 is started, the pressure difference between the compressor suction and discharge is small, and stable startability can be secured.

A method of switching the compressor between operation and stop of the four-way valve 6 is, for example, using an electromagnetic coil or the like. When the electromagnetic coil is energized, A and B and C and D communicate with each other. In some cases, when the energization is stopped, two systems of circuits that switch A and D and B and C communicate with each other are switched. In order to maximize the energy saving, it is best to use a DC step motor rather than the electromagnetic coil type, and energize only when the valve position is moved, and not energize after the valve position is moved.

As described above, when the refrigeration cycle is stopped, the refrigerant on the high-pressure side does not flow to the evaporator 5 and the temperature of the evaporator 5 does not increase, so that the loss of the refrigeration cycle can be reduced. In addition, the compressor 1 is placed in a high pressure state before and after the compressor 1, and the differential pressure is small, and the compressor 1 can be started without requiring a large torque. In addition, during the operation of the refrigeration cycle, a normal refrigeration cycle is formed and normal cooling operation can be performed. When the refrigeration cycle is stopped, high and low pressures are separated on the cycle, and high-pressure refrigerant passes from the dryer 3 to the compressor 1. Thus, the pressure difference between compressor suction / discharge can be reduced.

Further, by providing a four-way valve and switching the refrigeration cycle flow path according to the operation state of the refrigeration cycle,
Separate and maintain condensing / evaporating pressure when refrigeration cycle is stopped,
Shortening the defrost time saves energy and also ensures the startability of the compressor. Also, compared to the three-way valve, it realizes cost reduction by eliminating the bypass pipe and check valve, noise reduction, avoidance of refrigeration cycle blockage failure due to sludge, reduction of welding failure, high reliability and quietness, An energy-saving refrigerator can be provided.

If the position of the four-way valve is arranged immediately after the compressor 1, the low pressure gas stays in the machine room piping when the compressor 1 is stopped.
Secondary damage (corrosion of pipes due to rust / floor corrosion / tertiary damage due to urethane swelling, etc.) occurs. Therefore, by arranging the position of the four-way valve 6 as shown in FIG. 1, since the refrigerant is in the two-phase region, there is no need to upgrade the heat resistance of the winding due to the temperature of the refrigerant increasing in the gas region. Since the distance from the four-way valve 6 to the discharge portion of the compressor 1 is sufficient, sludge resistance (addition of a filter or the like) is not required. If the dryer 3 is provided before the four-way valve 6, the foreign matter removing function need not be provided in the four-way valve 6.

The refrigeration cycle having the above configuration will be described. FIG. 6 shows changes in the pressure state of each device when the refrigeration cycle in FIGS. 1 and 2 is operated or stopped. Is the pressure from the outlet of the compressor 1 through the condenser 2 to the inlet A of the four-way valve 6, and is the pressure B of the four-way valve 6
From the outlet of the capillary 3 to the inlet C of the four-way valve 6 via the evaporator 4, and the pressure from the outlet D of the four-way valve 6 to the suction part of the compressor 1.

During the operation of the refrigeration cycle, the four-way valve 6 is A and B,
Make C and D communicate. In FIG. 1, represents the condensing pressure, and represents the evaporating pressure. The inside of the refrigerator is cooled to a predetermined temperature, and the refrigeration cycle stops.

When the refrigeration cycle is stopped, A and D of the four-way valve 6
Communication. The high-pressure refrigerant in the condenser 2 flows into the inlet of the compressor 1. B and C communicate with each other and are balanced by the evaporation pressure. As a result, in FIG. 2, is the condensing pressure,
Remains at the evaporation pressure. Here, the timing of communication between A and D may be simultaneous with the stop of the refrigeration cycle or at an arbitrary time (several seconds to several minutes) immediately before the start of the compressor. In addition, the amount of leakage from the high pressure side of A and D to the low pressure side of B and C inside the four-way valve 6 is minimized (for example, 5% or less of the refrigerant flow rate during the refrigeration cycle operation).

In FIG. 6, the pressure when the compressor 1 is stopped is balanced. Therefore, as shown in FIG. 2, the front and rear of the compressor are balanced by communicating the high pressure region with the four-way valve 6. When the compressor 1 is stopped, the pressure on the low pressure side is balanced, but the circuit in the low pressure range does not include the compressor 1 and does not need to be communicated (it may be communicated). ).

As described above, when the temperature in the refrigerator becomes high and the compressor 1 is started, the pressure required for the suction and discharge of the compressor is balanced, so that the required starting torque of the compressor 1 can be reduced. By switching the flow path of the four-way valve 6 after the compressor 1 starts, the pressure rise immediately after the start is small, so that the acceleration torque is also small. Further, even if a pressure difference is generated by switching the four-way valve 6 after the operation of the compressor 1 is stabilized, the operation can be continued without stopping because of the inertia due to the operation of the compressor 1.

In the defrosting operation, the four-way valve 6 communicates A and B, and C and D, respectively, to form the same cycle as in the refrigeration cycle operation. Defrost heat is also supplied from the refrigerant. When the compressor 1 is stopped, the defrosting time can be reduced by forming the same flow path as during the compressor operation only during defrosting.

[0028]

Since the present invention is configured as described above, it has the following effects.

The refrigerating cycle of the refrigerator according to the first aspect of the present invention includes a compressor, a condenser, a capillary, and an evaporator connected in this order, and a four-way switching valve provided between the condenser and the capillary and between the evaporator and the compressor. A non-return valve, bypass piping, and the like are not provided, and the refrigeration cycle is inexpensive, highly reliable, and silent.

The refrigerating cycle of the refrigerator according to claim 2 is
The four-way valve communicates between the condenser outlet and the capillary inlet and between the evaporator outlet and the compressor inlet when the compressor is operating, and between the condenser outlet and the compressor inlet and between the evaporator outlet and the capillary inlet when the compressor is stopped. Therefore, even when the compressor is stopped, no pressure difference is generated between the inlet and the outlet of the compressor, and the compressor can be restarted without requiring a large torque.

The refrigeration cycle of the refrigerator according to claim 3 is as follows:
Since the four-way valve communicates between the condenser outlet and the capillary inlet and between the evaporator outlet and the compressor inlet during the defrosting operation, the defrosting time can be reduced.

The refrigeration cycle of the refrigerator according to claim 4 is as follows:
Even if the compressor is a low-pressure shell compressor, a small difference in pressure between the suction side and the discharge side of the compressor ensures stable startability of the compressor.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram of a refrigerator according to a first embodiment of the present invention.

FIG. 2 is a cycle diagram when the refrigeration cycle is stopped according to the present invention.

FIG. 3 is a diagram showing a refrigerant flow path of a refrigeration cycle of a refrigerator as a first conventional example.

FIG. 4 is a graph showing pressure changes at various points in the refrigeration cycle of FIG. 3;

FIG. 5 is a diagram showing a refrigerant flow path of a refrigeration cycle of a refrigerator as a second conventional example.

FIG. 6 is a graph showing pressure changes at various parts in the refrigeration cycle of FIG. 5 and FIGS. 1 and 2;

[Explanation of symbols]

1 Compressor, 2 condenser, 3 dryer, 4 capillary, 5 evaporator, 6 4-way valve, 7 3-way valve, 8 bypass, 9 check valve.

Claims (4)

[Claims] 1. A refrigerating cycle for a refrigerator, comprising a compressor, a condenser, a capillary, and an evaporator connected in this order, and a four-way switching valve provided between the condenser and the capillary and between the evaporator and the compressor. . 2. The four-way valve communicates between the condenser outlet and the capillary inlet and between the evaporator outlet and the compressor inlet during operation of the compressor, and communicates with the condenser outlet when the compressor is stopped. 2. The refrigerating cycle of a refrigerator according to claim 1, wherein the compressor communicates between an inlet of a compressor and an outlet of the evaporator and an inlet of the capillary. 3. The method according to claim 1, wherein the four-way valve communicates between the condenser outlet and the capillary inlet and between the evaporator outlet and the compressor inlet during the defrosting operation. Refrigeration cycle of the refrigerator. 4. The refrigeration cycle of a refrigerator according to claim 1, wherein the compressor is a low-pressure shell compressor.