JPH0534027A - Freezer - Google Patents

Abstract

PURPOSE:To provide a freezer in which frosting is hardly generated within an evaporator and also within a freezer. CONSTITUTION:A freezer is comprised of a compressor 1, a condensor 2, a receiver 3, an expansion valve 4, an evaporator 6, a solenoid valve 7, a positive pressure expansion valve 8, a sub-evaporator 9 and a solenoid valve 10 having an adjusting means. In the case that sucked air 102 shows a temperature higher than 0 deg.C, the solenoid valve 10 is opened, the sucked air 102 is cooled to a condensed water non-freezing temperature slightly higher than 0 deg.C and then the air is sent to the evaporator 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator for cooling the inside of a cool box to a temperature below freezing.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a compressor 110, a condenser 120, a receiver 130, a valve 140, a main evaporator 150, and a check valve 160.
Valve 21 to the main refrigeration cycle 100
0, a frost evaporator 220, and a frost refrigeration cycle 200 having a magnet valve 230 are attached, and by closing the valve 140 when the door of the cool box is opened, frost formation on the main evaporator 150 can be prevented, A refrigerator T that prevents a rapid temperature rise in the cool box is known (Nippon Denso Koho Giho January 15, 1986).
Daily reference number 45-090).

[0003]

However, the conventional refrigerator T has the following problems. (A) Since a large amount of frost adheres to the frost formation evaporator 220 in a short time, it is necessary to defrost the frost formation evaporator 220 in a short cycle (the required time is 1 hour). When is opened, air with a large amount of water vapor enters the cool box, and the main evaporator 150 is rapidly frosted. (A) Frost is accumulated on the main evaporator 150 and accumulates over time even if the door of the cool box is not opened often. The frost on the main evaporator 150 cannot be defrosted even if the magnet valve 230 is opened. An object of the present invention is to provide a refrigerator in which frost does not easily form in the evaporator and the cool box.

[0004]

[Means for Solving the Problems] In order to solve the above problems,
The present invention has the following configurations. (1) A compressor that adiabatically compresses a low-temperature low-pressure refrigerant gas into a high-temperature high-pressure refrigerant gas, a condenser that cools the high-temperature high-pressure refrigerant gas to liquefy it, and is connected to the condenser to discharge the liquid refrigerant. Along with, a receiver that stores the refrigerant in a gas-liquid two-phase state, an expansion valve that expands the liquid refrigerant discharged from the receiver to a low-temperature low-pressure liquid refrigerant, and a low-temperature low-pressure liquid refrigerant to evaporate Is cooled to a predetermined temperature below the freezing point, and an evaporator that returns the vaporized low-temperature low-pressure refrigerant gas to the compressor, and during defrosting, hot gas defrosting that bypasses the high-temperature high-pressure refrigerant gas of the compressor to the inlet side of the evaporator. Means and a constant pressure expansion valve for introducing a liquid refrigerant discharged from the discharge side of the receiver and expanding the liquid refrigerant into a low temperature low constant pressure liquid refrigerant , A sub-evaporator for evaporating the low-temperature low-constant-pressure liquid refrigerant to cool the air entering the cold storage to a condensed water unfreezing temperature of approximately 0 ° C., and a refrigerant gas of the sub-evaporator for the low-pressure side of the compressor. And a solenoid valve with a throttle, which is arranged between the return pipes and opens when the incoming air exceeds a set temperature of approximately 0 ° C. (2) A compressor that adiabatically compresses a low-temperature low-pressure refrigerant gas into a high-temperature high-pressure refrigerant gas, a condenser that cools the high-temperature high-pressure refrigerant gas and liquefies it, and a low-temperature low-pressure liquid refrigerant that expands this liquid refrigerant. A fixed throttle, an evaporator for evaporating the low-temperature low-pressure liquid refrigerant to cool the inside of the cool box to a predetermined temperature below the freezing point, and discharging the vaporized low-temperature low-pressure refrigerant gas, and is arranged in front of the compressor. An accumulator for buffering pressure fluctuations of the refrigerant gas, a hot gas defrosting means for bypassing the high-temperature and high-pressure refrigerant gas of the compressor to the inlet side of the evaporator during defrosting, and a liquid refrigerant discharged from the condenser are introduced. A constant pressure expansion valve that expands this liquid refrigerant into a low temperature low constant pressure liquid refrigerant, and evaporates this low temperature low constant pressure liquid refrigerant, and introduces air into the cool box. , A sub-evaporator that cools the condensed water to a non-freezing temperature of approximately 0 ° C. and a pipeline that returns the refrigerant gas of the sub-evaporator to the inlet side of the accumulator, and the incoming air has a set temperature of approximately 0 ° C. And a solenoid valve with a throttle that opens when exceeding.

[0005]

When the incoming air exceeds the set temperature of about 0 ° C, the solenoid valve with a throttle opens and the sub-evaporator cools the incoming air to the freezing temperature of the condensed water of about 0 ° C (when defrosting). But) The water vapor contained in the incoming air is condensed by the sub-evaporator, and this condensed water falls into drain water without freezing and is discharged to the outside. The evaporator uses the incoming air cooled to the condensed water antifreeze temperature of approximately 0 ° C.
Cool to a predetermined temperature below the lower freezing point.

[0006]

EFFECTS OF THE INVENTION Since the evaporator further cools the incoming air having a low water vapor content and cooled to the non-freezing temperature of the condensed water of approximately 0 ° C., the evaporator and the cold storage are less likely to be frosted and the refrigerating capacity can be maintained. In addition, the time from defrost to the next defrost can be extended.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. The refrigerator R includes a compressor 1, a condenser 2, a receiver 3, an expansion valve 4, and a cool box 5.
It has an evaporator 6 for cooling the inside, a solenoid valve 7 for hot gas bypass, a constant pressure expansion valve 8, a sub-evaporator 9, and a solenoid valve 10 with a throttle.

The compressor 1 is driven by an engine or an electric motor and adiabatically compresses the low-temperature low-pressure refrigerant gas 11 into a high-temperature high-pressure refrigerant gas 12. The condenser 2 is connected to the high-pressure side valve of the compressor 1 and is provided with a condenser fan (not shown) to cool the high-temperature and high-pressure refrigerant gas 12 into a liquid refrigerant 21. The receiver 3 is connected to the outlet side of the condenser 2 and stores the refrigerant (R-12) in a gas-liquid two-phase state so that the liquid refrigerant 21 can be discharged to the evaporator 6 in response to a change in load. The expansion valve 4 is the liquid refrigerant 2 discharged from the receiver 3.
1, a needle valve that rapidly expands into a low-temperature low-pressure atomized liquid refrigerant 22, a pressure spring that urges the needle valve, the inside of the capillary tube 41 and the outlet-side pipe 61,
A diaphragm that adjusts the opening degree of the needle valve by the hydraulic pressure of the refrigerant (R-12) sealed in the heat sensitive cylinder 42 arranged in the pipe 13 is provided at a position slightly downstream of the connection point of 91.

The cold storage 5 is a box for storing frozen objects such as frozen foods, and a door (not shown) for putting in and out the frozen objects.
Are provided on the sub-evaporator 9 side. The evaporator 6 is connected to the outlet side of the expansion valve 4 and arranged in the cool box 5 to evaporate the low-temperature low-pressure mist-like liquid refrigerant 22. Due to the latent heat of the evaporator 6, the evaporator box 6-
Cool to 20 ° C. The low-temperature low-pressure refrigerant gas 11 vaporized in the evaporator 6 is returned to the compressor 1.

The solenoid valve 7 is opened when the amount of frost adhering to the evaporator 6 increases and defrosting becomes necessary, and the high temperature and high pressure refrigerant gas 12 is bypassed from the high pressure side of the compressor 1 to the inlet side of the evaporator 6. . The solenoid valve 7 is opened by using a timer or frost detection means such as an optical type or a pressure type.

The constant pressure expansion valve 8 is arranged in a pipe 81 connecting the outlet of the receiver 3 and the sub-evaporator 9 in series, and rapidly expands the liquid refrigerant 21 to let out a low-temperature low-constant-pressure mist-like liquid refrigerant 23. .

The sub-evaporator 9 is connected to the outlet side of the constant pressure expansion valve 8 and is connected to the evaporator 6 inside the cool box 5.
When the outside air is inhaled (when the door is open,
During ventilation, etc., the liquid refrigerant 23 is evaporated, and due to the latent heat of the liquid refrigerant 23, the intake air 102 is cooled to a non-freezing temperature of the condensed water slightly higher than 0 ° C. and sent to the evaporator 6. The surface of the sub-evaporator 9 for heat exchange is coated with a hydrophobic material (fluorine resin or the like) to facilitate the fall of the condensed water.

As shown in FIG. 2, when the thermistor 101 detects a temperature Ta of the intake air 102 exceeding 0 ° C., the solenoid valve 10 is energized by the controller 103 and opens. When the temperature Ta of the intake air 102 is 0 ° C. or less (when the door is closed and the outside air is not introduced, or the outside air temperature is 0).
Since it is not necessary to cool the intake air 102, the energization is not performed and the solenoid valve 10 maintains the closed state.

Next, the operation of the refrigerator R (intake air 102
(When the temperature Ta exceeds 0 ° C.) will be described with reference to the moist air diagram of FIG. It is assumed that the intake air 102 (= outside air) is at 25 ° C. and 50% RH (position A in the figure). When the door of the cool box 5 is opened, the thermistor 101 detects the temperature Ta of the intake air 102 exceeding 0 ° C., and the controller 103
Thus, the solenoid valve 10 is energized, the solenoid valve 10 is opened, and the sub-evaporator 9 operates. The intake air 102 is
It is cooled by the sub-evaporator 9, passes through the position B in the figure, and reaches approximately 0
C., 100% RH (position C in the figure). Here, when the state is changed from the illustrated position B to the illustrated position C, the water (B-C) is condensed, so that the frost falls from the hydrophobic material of the sub-evaporator 9 in a liquid state to the outside as drain water. Is discharged. The cooling air of approximately 0 ° C. and 100% RH is further cooled by the evaporator 6 to −20 ° C. and 100% RH (position D in the figure).
When the state is changed from the illustrated position C to the illustrated position D, the water (C-D) is condensed and adheres to the surface of the evaporator 6 as frost. If the intake air 102 at 25 ° C. and 50% RH is cooled to −20 ° C. and 100% RH all at once, about 3.17 times as much water (BD) is condensed.

The effects of the refrigerator R will be described below. (A) The amount of frost that attaches to the evaporator 6 and the cool box 5 is 1/3 or less (in the case of summer) compared to a refrigerator that cools to -20 ° C at once. Therefore, the time from defrost to the next defrost can be tripled or longer (in the case of summer). (Ii) It is stable because the frost does not easily form on the evaporator 6.
Highly efficient refrigeration operation is possible. (V) When the frost formation on the evaporator 6 is reduced, the fin blockage due to the frost formation is reduced, the reduction of the ventilation resistance is suppressed, a high air volume can be secured with the same fan, and the refrigeration capacity during operation is high. Become.

A second embodiment of the present invention will be described with reference to FIG. The refrigerator S has the same configuration as the refrigerator R except that the receiver 3 is removed, the expansion valve 4 becomes a CTD (composite expansion device) 4a, and an accumulator tank 3a is arranged in front of the compressor 1. is there. The refrigerator S of this embodiment also has the same effect as the refrigerator R.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a refrigerator according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of a controller of the refrigerator.

FIG. 3 is a moist air diagram for explaining the effect of the refrigerator.

FIG. 4 is a structural explanatory view of a refrigerator according to a second embodiment of the present invention.

FIG. 5 is a structural explanatory view of a conventional refrigerator.

[Explanation of symbols]

1 compressor 2 capacitors 3 receiver 4 expansion valve 5 cold storage 6 evaporator 7 Solenoid valve (hot gas defrosting means) 8 constant pressure expansion valve 9 Deputy evaporator 10 Solenoid valve 3a Accumulator tank (accumulator) 4a CTD (fixed diaphragm) 102 Intake air (ingress air) R, S refrigerator

Claims (2)

[Claims] 1. A compressor for adiabatically compressing a low-temperature low-pressure refrigerant gas into a high-temperature high-pressure refrigerant gas, a condenser for cooling the high-temperature high-pressure refrigerant gas and liquefying it, and a liquid refrigerant connected in series to the condenser. As well as discharging
A receiver that stores the refrigerant in a gas-liquid two-phase state, an expansion valve that expands the liquid refrigerant discharged from the receiver to a low-temperature low-pressure liquid refrigerant, and an evaporator valve that evaporates the low-temperature low-pressure liquid refrigerant and freezes the inside of the cool box. An evaporator that cools the vaporized low-temperature low-pressure refrigerant gas to the compressor, and a hot gas defroster that bypasses the high-temperature high-pressure refrigerant gas of the compressor to the inlet side of the evaporator during defrosting. Introducing a liquid refrigerant discharged from the discharge side of the receiver,
A constant-pressure expansion valve that expands this liquid refrigerant to a low-temperature low-constant-pressure liquid refrigerant, and evaporates this low-temperature low-constant-pressure liquid refrigerant so that the air that enters the cold storage box has a condensed water antifreezing temperature of approximately 0 ° C. And a sub-evaporator for cooling the sub-evaporator and a pipe provided with a throttle, which is arranged between the pipes for returning the refrigerant gas of the sub-evaporator to the low pressure side of the compressor and opens when the incoming air exceeds a set temperature of approximately 0 ° C. A refrigerator having a solenoid valve. 2. A compressor for adiabatically compressing a low-temperature low-pressure refrigerant gas into a high-temperature high-pressure refrigerant gas, a condenser for cooling the high-temperature high-pressure refrigerant gas and liquefying it, and expanding the liquid refrigerant for low-temperature low-pressure refrigerant gas. A fixed throttle that turns into a liquid refrigerant, an evaporator that evaporates the low-temperature and low-pressure liquid refrigerant to cool the inside of the cool box to a predetermined temperature below the freezing point, and discharges the vaporized low-temperature and low-pressure refrigerant gas, and an evaporator in front of the compressor. An accumulator installed to buffer pressure fluctuations of the refrigerant gas, a hot gas defrosting means for bypassing the high temperature and high pressure refrigerant gas of the compressor to the inlet side of the evaporator during defrosting, and a liquid refrigerant discharged from the condenser. And a constant pressure expansion valve that expands the liquid refrigerant into a low temperature low constant pressure liquid refrigerant, and evaporates the low temperature low constant pressure liquid refrigerant, The ingress air, a secondary evaporator for cooling the condensed water not freezing temperature of about 0 ℃, is disposed refrigerant gas sub evaporator between conduit for returning to the inlet side of the accumulator, the approach air substantially 0 ℃
A refrigerator having a solenoid valve with a throttle that opens when the temperature exceeds the set temperature.