JPS6146367Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a refrigeration system such as an electric refrigerator, and more particularly to a control device for a refrigeration system that reduces energy loss during operation and stop of a refrigeration cycle.

Generally, in a refrigerator or the like, in order to maintain the internal temperature at a predetermined temperature, cooling operation and stopping are repeated over a certain temperature range. When the temperature inside the refrigerator drops to a predetermined temperature, this temperature is sensed and a signal to stop the cooling operation is issued, the electric compressor stops, and the refrigerant state in each part of the refrigeration cycle changes toward balance. In other words, the high-pressure side from the discharge valve of the electric compressor to the inside of the shell and condenser and the low-pressure side from the cooler to the suction port in the electric compressor maintain a balance pressure. Since the high-pressure gas refrigerant moves from the high-pressure gas refrigerant to the low-pressure side low-temperature part (in this case, the cooler), the inside of the cooler is filled with refrigerant. The temperature of the cooler rises due to the surrounding heat, but the heat of condensation when the refrigerant flowing into the cooler from the capillary or electric compressor condenses and liquefies causes the temperature to rise rapidly and warm the surrounding air. It often happens.

Therefore, when the temperature inside the refrigerator rises to a predetermined temperature and the electric compressor receives a cooling operation signal and is operated, the liquid refrigerant that has accumulated in the cooler is not completely evaporated in the cooler and reaches the electric compressor. Since the inside of the piping is cooled and then flows to the electric compressor, the inside of the refrigerator is not effectively cooled for several minutes after startup, resulting in energy loss. When it is sucked into the machine, the compression work increases and the electric motor becomes overloaded, so the input is usually extremely large, and a larger electric motor is inevitably used to deal with this.

The present invention was devised for the purpose of solving the problems in such conventional refrigerant systems, and the present invention will be described in detail below with reference to the illustrated embodiments.
2 is a condenser, 3 is a capillary tube, and 4 is a cooler, which are connected in sequence to form a refrigeration cycle. are doing. Reference numeral 5 denotes a check valve connected to the piping between the electric compressor 1 and the cooler 4. Reference numeral 6 denotes an on-off valve such as a solenoid valve, which is connected in the piping path between the condenser 2 and the capillary tube 3.

Reference numeral 7 denotes a gas reservoir, which is disposed in the piping path between the check valve 5 and the electric compressor 1.

Next, to explain the operation of the refrigeration cycle constructed from these, a refrigerant circulates within the refrigeration cycle, and in a refrigerator that is in cooling operation, when the temperature inside the refrigerator drops to a predetermined temperature, a temperature sensor etc. A stop signal is issued and the solenoid valve 6 is operated to cut off the refrigerant flow to the cooler 4.

Furthermore, when a stop signal is issued, the high-temperature, high-pressure gas refrigerant confined within the high-pressure shell flows back toward the cooler 4 through the oil film seal on the sliding surface of the rolling piston 1a and the like. At this time, a check valve 5 connected to the piping between the cooler 4 and the electric compressor 1 to prevent backflow from the electric compressor 1 to the cooler 4 instantly blocks the piping, This prevents the temperature from rising due to the high-temperature, high-pressure gas refrigerant in the cooler 4. As shown in Fig. 2, the pressure change after a refrigerant cycle stop signal is issued by a temperature sensor, etc. is a high pressure curve a in the conventional refrigeration cycle.
The gas refrigerant sealed in the high-pressure shell leaks from the condenser 2, whose balance state is on the high-pressure side, through the capillary tube 3, and from the sliding surfaces of the rolling piston 1a, etc., resulting in the so-called low-pressure side cooler. In contrast, in the embodiment of the present invention, the refrigerant flows from inside the high-pressure shell of the electric compressor 1 through the condenser 2. The internal pressure a' up to the solenoid valve 6 exhibits a pressure state higher than the conventional high-pressure side pressure, and gradually stabilizes at the same saturation pressure as the outside temperature.

On the other hand, the low-pressure side pressure b' from the cooler 4 to the check valve 5 disposed in the piping of the electric compressor 1 indicates that there is no refrigerant intruding from the high-pressure side, and the refrigerant is confined on the low-pressure side immediately after the stop. flows into the part of the cooler 4 where the temperature has dropped the most, and is affected by heat from the surroundings of the piping and the cooler 4, causing a short delay until the next cooling operation start signal is issued and the electric compressor 1 starts. As with the pressure state on the high pressure side during stoppage, the pressure state on the low pressure side can also be maintained in a state extremely close to the pressure state during normal operation, by increasing the pressure gradually. Furthermore, when the electric compressor 1 is stopped, the high pressure gas in the shell is checked by the sliding surface of the rolling piston 1a, etc. of the electric compressor 1, which has a high pressure shell of the rolling piston 1a type, which is an embodiment of the present invention. A reverse flow passes through the oil film seal on the sliding surface in the direction of the valve 5 due to the force of the differential pressure, and at the same time the check valve 5 is operated, a high pressure curve a'' is shown between the electric compressor 1 and the check valve 5. Electric compressor 1 at high pressure
You can balance the front and back.

Next, when a signal to start cooling operation is issued by a temperature sensor or the like, the solenoid valve returns to the open state, and the electric compressor 1 also starts operating at the same time. Then, the liquid refrigerant that conventionally accumulated in the cooler 4 during stoppage,
Since the cooler 4 is hardly cooled, the refrigerant returns to the electric compressor 1 and causes a pressure increase. However, in the present invention, the room temperature high pressure refrigerant accumulated in the condenser 2 in a liquefied state is transferred to the electric compressor 1. When the electric compressor 1 is started, the refrigerant flows through the capillary tube 3 to reduce the pressure, evaporates in the cooler 4, performs a cooling action, and then returns to the electric compressor 1 as a gaseous refrigerant. It is possible to reduce the input by reducing the load on the motor, and the motor can be made smaller than before.

In particular, in this invention, the check valve 5 and the electric compressor 1
Immediately after the electric compressor 1 starts, the electric compressor 1 sucks the gas in the gas reservoir, and then the pressure changes from a'' to the pressure b' of the cooler 4. The time for the pressure difference between the pressures before and after (a′ and a″) to occur becomes longer, and the load on the motor due to the pressure difference occurs after the motor reaches a steady rotational operating state, so the starting torque of the motor can be reduced. It is possible.

Since the present invention is configured as described above, it is possible to eliminate energy loss caused mainly by the movement of refrigerant in a conventional refrigeration cycle, especially immediately after operation and stoppage of the refrigeration cycle, and at the same time, This makes it possible to downsize the motor of the electric compressor and improve energy efficiency even during normal operation. It should be noted that the control signals for the on-off valve and the electric compressor when the electric compressor is stopped and operated in the present invention may be controlled sequentially by electronic control or the like.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration circuit diagram according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing the pressure balance state after the refrigeration cycle is stopped in the refrigeration cycle of the present invention and the conventional refrigeration cycle. 1 is an electric compressor, 2 is a condenser, 3 is a capillary tube, 4
is a cooler, 5 is a check valve, 6 is an on-off valve, and 7 is a gas reservoir.

Claims (1)

[Scope of utility model registration request] Electric compressor, condenser, with high pressure inside the shell,
In a refrigeration cycle in which a capillary tube and a cooler are successively connected, a check valve is provided in a part of the piping connecting the electric compressor and the cooler, and a refrigerant gas reservoir is provided between the check valve and the compressor. 1. A refrigeration system characterized by comprising: an on-off valve between the condenser and the capillary;