JP3475202B2 - Superheat control device for capillary tube - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to superheat control using a capillary tube which is a fixed throttle for decompressing and expanding a medium, which is used in a small refrigeration and refrigeration system such as a home refrigerator / freezer and a vending machine. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, in a small refrigerating and refrigerating system used for household refrigerator-freezers and vending machines, a capillary tube which is a fixed throttle has been used as an apparatus for decompressing and expanding an inexpensive refrigerant. As shown in FIG. 9, the refrigerating circuit using this capillary tube sends the refrigerant sent from the compressor 21 via the condenser 22 to the capillary tube 23 to perform pressure reduction and adiabatic expansion, and to cool this refrigerant in the evaporator 24. To the compressor 21 for freezing and cooling.

In a refrigeration system using such a capillary tube, the flow rate of the refrigerant sent to the evaporator is
Basically, it is determined by the inner diameter of the capillary tube and the length of the capillary tube, and the flow rate fluctuation with self-controllability depends on the amount of refrigerant filled in the device, the condensation pressure, and the degree of supercooling at the capillary tube inlet. It has been decided that in this system, the evaporation pressure and the inherent evaporator control cannot be performed.

[0004]

In the refrigeration system using the capillary tube as described above, the evaporator cannot be controlled originally, and the flow rate cannot be controlled under load conditions. Even in a tube-based refrigeration system, flow rate control is performed in response to changes in the condenser temperature and the evaporator outlet temperature, so that the condenser is undercooled and the evaporator outlet temperature is overheated. It is desirable to return to the compressor at.

As a countermeasure, in the system proposed in Japanese Patent Publication No. 62-40631 as shown in FIG. 10, as shown in FIG. 9, the basic structure is a refrigeration circuit using a conventional capillary tube. Similarly, the refrigerant sent from the compressor 31 via the condenser 32 is sent to the capillary tube 33 to be depressurized and expanded, and this refrigerant is sent to the evaporator 34 for freezing and cooling operations, and then returned to the compressor 31. In the refrigerating circuit, the refrigerant amount control container 3
5, the refrigerant at the connection position 33a in the middle of the capillary tube 33 is introduced therein, and the refrigerant amount adjusting container 3
5, a suction pipe 36 that connects the outlet of the evaporator 34 and a suction hole of the compressor 31, and a branch pipe that branches from a branch point 37b in a pipe line 37 that connects the condenser 32 and the capillary tube to a confluence point 37c. 37a is penetrated and it is in the heat exchange state.

In this apparatus, the pipe diameter of the connecting pipe or the relation of the branch pipes is appropriately selected by the above-mentioned configuration, so that the refrigerant amount that can be stored in the refrigerant amount control container can be arbitrarily selected under the design load condition. , By this, the size of the refrigerant amount adjusting container is determined so that the refrigerant amount adjusting function can be fulfilled with respect to the maximum load condition and the minimum load condition that can be considered at the time of design, and in particular, the refrigerant amount is adjusted at the time of low load. As a result, the liquid returns to the compressor. However, in the above device, the branch pipe 37a
The wetness is constant depending on the pipe diameter, and the operating efficiency is poor. Further, since the working refrigerant is used, there is a defect that heat exchange is not sufficiently performed.

As another measure, in a refrigeration system using a capillary tube, a heat exchanger for cooling the capillary tube, a control valve, and a control valve are used by utilizing the fact that the flow rate changes depending on the degree of supercooling at the inlet of the capillary tube. It has been proposed to control the evaporator by a microcomputer using a superheat detection sensor, etc., but in such a case, it is only possible to cope with the limited flow rate control area of the capillary tube. However, the use of the above-mentioned equipment for the effect is costly and has a drawback in terms of reliability.

Therefore, the present invention provides a refrigeration circuit using a capillary tube while maintaining its characteristics and reliability by using the capillary tube.
It is an object of the present invention to provide an inexpensive capillary tube superheat degree control device capable of feeding back the state of the evaporator which is the original control target in the control of the refrigerant circuit without using a special control device.

[0009]

In order to solve the above problems, the present invention provides a compressor, a condenser, a capillary tube,
In a superheat degree control device for a capillary tube of a refrigeration system in which an evaporator is sequentially connected to form a refrigerant circuit, a heat pipe container containing a medium is provided, and the inside of the heat pipe container is divided into two chambers on the left and right sides and both chambers are provided. A capillary tube penetrating the heat pipe container is housed in one chamber, and the other chamber is in a heat exchange state with the evaporator outlet pipe, thereby forming a superheat control device for the capillary tube. Is.

Since the present invention is configured as described above, when the capillary tube outlet temperature (evaporator inlet temperature) is lower than the evaporator outlet temperature, that is, in the overheated state,
The medium in the heat pipe container is condensed and dripped in the chamber in which the capillary tube is stored, and is collected in this chamber. By repeating this, the capillary tube is cooled, the degree of supercooling of the refrigerant passing through the capillary tube is increased, and the capillary tube acts to increase the flow rate. Further, when the evaporator outlet temperature is low, that is, in the liquid back state, the medium in the heat pipe container is condensed and dropped in the room where the capillary tube is not housed, and is collected in this room, and the capillary tube is cooled. It is not done and acts in the direction of decreasing the flow rate.
By repeating this, control is performed according to the state of the evaporator.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described based on embodiments with reference to the drawings.

[0012]

【Example】

(Embodiment 1) The basic configuration of the refrigeration circuit is the same as that of the conventional one shown in FIG. 9, and as shown in FIG. 1, the refrigerant from the compressor 1 is a condenser 2, a capillary tube 3, and an evaporator. Four
It has a refrigerant circuit through which it returns to the compressor 1. This refrigerant circuit has a heat pipe container 5 that functions as a heat pipe, and has CF ₃ CHCl ₂ (refrigerant number R-1 inside).
23), CF ₃ CH ₂ F (refrigerant number R-134a), and the like, which have a larger specific volume and a larger latent heat than the working refrigerant and are sealed.
It is divided into a chamber 7 and a second chamber 8. A capillary tube 3 penetrating the heat pipe container 5 is accommodated in the first chamber 7, and an evaporator outlet pipe 10 penetrating the heat pipe container 5 is accommodated in the second chamber 8.

In a refrigeration circuit using such a capillary tube, the capillaries have the same overall length and inner diameter, and when the outside air temperature changes, the states when the outside air temperature changes are Pc ₁ , Pc ₂ , Pc ₃ 4, the flow rate characteristic as shown in FIG. 4 is exhibited, and the larger the supercooling degree ΔT of the refrigerant at the inlet of the capillary tube is, the larger the flow rate G of the refrigerant flowing therethrough is. The larger the pressure PC at the tube inlet, the greater the flow rate flowing through it.

In the apparatus having the above structure, when the refrigerant in the evaporator outlet pipe 10 is in an overheated state, the capillary tube outlet temperature, that is, the evaporator inlet temperature TE is equal to the evaporator outlet temperature T.
When it is lower than S, as shown in FIG. 2, the medium in the heat pipe container is condensed at the outlet (evaporator inlet) of the capillary tube 3 which is the coldest portion, drops, and collects in the first chamber 7. By repeating this cycle, the temperature of the medium accumulated in the first chamber 7 is lowered. By this action, the capillary tube 3 is cooled, and the supercooling degree of the refrigerating refrigerant passing through the capillary tube 3 increases. As described above, the larger the cooling degree of the refrigerant, the more the flow rate of the refrigerant flowing through the capillary tube 3 acts. .

On the contrary, when the evaporator outlet temperature TS is lower than the capillary tube outlet temperature (evaporator inlet temperature) TE, that is, in the liquid back state, as shown in FIG. It is condensed in a portion of the evaporator outlet pipe 10 which is a low temperature portion, drops, and accumulates in the second chamber 8. By repeating this cycle, the medium is accumulated in the second chamber 8, the heat recovery in the first chamber 7 is not performed, the capillary tube 3 is not cooled, and the characteristics of the capillary tube and the amount of refrigerant on the condenser side are reduced. Due to the decrease in supercooling, the capillary tube is no longer cooled,
It acts to reduce the flow rate.

(Embodiment 2) In the first embodiment, an example is shown in which the evaporator outlet pipe is arranged in the second chamber of the heat pipe container, but as shown in FIG. 5, it contacts the second chamber 8. It is placed in contact with the outer wall 11 of the heat pipe container 5.
Also in this embodiment, when the capillary tube outlet temperature TE (evaporator inlet temperature) TE is lower than the evaporator outlet temperature TS, that is, in the overheated state, the medium in the heat pipe container 5 is stored in the capillary tube 3 first. 1
It is condensed and dripped in the chamber 8 and accumulated in this chamber. By repeating this, the capillary tube 3 is cooled, the degree of supercooling of the refrigerant passing through the capillary tube 3 increases, and the capillary tube 3 acts to increase the flow rate. When the evaporator outlet temperature TS is lower than the capillary tube outlet temperature (evaporator inlet temperature) TE, that is, in the liquid back state, the medium in the heat pipe container is the second tube in which the capillary tube 3 is not stored.
It condenses and drops in the chamber 8 and collects in this chamber, and the capillary tube 3 is no longer cooled and acts in the direction of decreasing the flow rate. By repeating this, control is performed according to the state of the evaporator.

(Embodiment 3) Further, as shown in FIG. 6, the heat pipe container is divided into two left and right chambers 7, 8.
8 is connected at the upper part by a connecting pipe 13, a capillary tube 3 penetrating the heat pipe container is housed in the first chamber 7, and the evaporator outlet pipe 10 is brought into contact with the outer wall of the second chamber 10. Constitute.

In the apparatus having the above structure, when the refrigerant in the evaporator outlet pipe 10 is in an overheated state, the capillary tube outlet temperature, that is, the evaporator inlet temperature TE is the evaporator outlet temperature T.
When it is lower than S, as shown in FIG. 7, the medium in the heat pipe container is condensed at the outlet (evaporator inlet) of the capillary tube 3 which is the coldest portion, drops, and collects in the first chamber 7. By repeating this cycle, the temperature of the medium accumulated in the first chamber 7 is lowered. By this action, the capillary tube 3 is cooled, and the supercooling degree of the refrigerating refrigerant passing through the capillary tube 3 increases. As described above, the larger the cooling degree of the refrigerant, the more the flow rate of the refrigerant flowing through the capillary tube 3 increases. .

On the contrary, in the case where the evaporator outlet temperature TS is lower than the evaporator inlet temperature TE, that is, in the liquid back state, as shown in FIG.
As shown in FIG. 3, the medium in the heat pipe container 5 is the connecting pipe 1.
After passing through 3, the gas is condensed in the second chamber 8 which is in contact with the evaporator outlet pipe 10 which is the lowest temperature part, and is dripped and accumulated in the second chamber 8. By repeating this cycle, the medium is accumulated in the second chamber 8, heat is not recovered in the first chamber 7, the capillary tube 3 is not cooled, and the capillary tube 3 is not cooled.
And the degree of supercooling due to the decrease in the amount of refrigerant on the condenser side, the capillary tube 3 is no longer cooled,
It acts to reduce the flow rate.

[0020]

As described above, according to the present invention, since the working refrigerant and the sealed refrigerant in the heat pipe are separately provided, sufficient heat exchange can be performed, the cooling of the refrigerating circuit can be quickly started, and the energy can be saved. Becomes Moreover, when the operation of the refrigeration circuit is stable, it does not become overcooled like the capillary tube. Further, the evaporator and the condenser can be downsized.
Also, while maintaining the characteristics and reliability of using the capillary tube, it is possible to feed back the state of the evaporator, which is the original control target in the control of the refrigerant circuit, without using special control equipment. It is possible to provide an inexpensive capillary tube superheat degree control device.

[Brief description of drawings]

FIG. 1 is a refrigeration circuit configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an essential part showing the first operating state.

FIG. 3 is a cross-sectional view of main parts showing a second operating state of the same.

FIG. 4 is a graph showing operating characteristics of the refrigeration circuit.

FIG. 5 is a cross-sectional view of essential parts of a second embodiment of the present invention.

FIG. 6 is a configuration diagram of a refrigeration circuit showing a third embodiment of the present invention.

FIG. 7 is a main-portion cross-sectional view showing the first operating state.

FIG. 8 is a main-portion cross-sectional view showing the second operating state.

FIG. 9 is a configuration diagram of a refrigeration circuit showing a conventional example.

FIG. 10 is a refrigeration circuit configuration diagram showing another conventional example.

[Explanation of symbols]

1 compressor 2 condenser 3 capillary tubes 4 evaporator 5 heat pipe containers 6 partitions 7 First room 8 second room 10 Evaporator outlet piping 13 Connection pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F25B 1/00 304 F25B 41/06

Claims (4)

(57) [Claims] 1. A compressor, a condenser, a capillary tube,
In a superheat degree control device for a capillary tube of a refrigeration system in which an evaporator is connected in sequence to form a refrigerant circuit, a heat pipe container containing a medium is provided, and the inside of the heat pipe container is divided into two chambers on the left and right and both chambers are separated. A superheat degree control device for a capillary tube, characterized in that a capillary tube penetrating a heat pipe container is housed in one chamber and communicated with the other in the upper chamber, and the other chamber is in a heat exchange state with an evaporator outlet tube. 2. The superheat degree control device for a capillary tube according to claim 1, wherein an evaporator outlet pipe penetrating the heat pipe container is housed in the other chamber. 3. The superheat degree control device for a capillary tube according to claim 1, wherein an evaporator outlet pipe is in contact with the outer wall of the other chamber. 4. The heat pipe container is divided into two left and right chambers, and both chambers are communicated with each other at the upper part by a connecting pipe. One chamber accommodates a capillary tube penetrating the heat pipe container, and the other chamber The superheat degree control device for a capillary tube according to claim 1, wherein the evaporator outlet pipe is brought into contact with the outer wall.