CN218781476U - Refrigeration and defrosting system - Google Patents

Abstract

The utility model discloses a refrigeration and defrosting system, belonging to the technical field of refrigeration and air-conditioning heat pump equipment, comprising a four-way valve, a condenser and an evaporator which are respectively communicated with the four-way valve, wherein the condenser and the evaporator are communicated through a pressure reduction pipeline; the high-pressure exhaust pipe of the compressor conveys refrigerant to the four-way valve, and the refrigerant flows back to the compressor through the low-pressure suction pipe of the compressor; and a pressure balancing mechanism is also connected between the high-pressure exhaust pipe and the pressure reduction pipeline. The utility model discloses a refrigeration and defrosting system of example, this system can solve refrigerating system and need shut down the problem that just can switch the cross valve and change the frost, makes the cross valve can satisfy the demand that low temperature freezer and low temperature cold wind change the frost, has reduced switching-over air current noise moreover.

Description

Refrigeration and defrosting system

Technical Field

The utility model relates to a refrigeration and air conditioner heat pump equipment technical field especially relate to a refrigeration and defrosting system.

Background

As is well known, the four-way valve of the air conditioner needs reversing defrosting and heating, but the four-way valve of the air conditioner can not reverse defrosting in the working state of the compressor, so the four-way valve of the air conditioner can not be used for defrosting on a low-temperature air cooler of a low-temperature cold storage. The reason is as follows: two pistons and two capillaries are arranged at two ends of the four-way joint, and the pistons push the sliding blocks to convert the flow direction of the refrigerant through the pressure of the capillaries; the left end of the capillary tube is provided with one capillary tube, the right end of the capillary tube is provided with one capillary tube, the two capillary tubes are supplied with liquid through an electromagnetic valve, and if the left end supplies high pressure, the right end is connected with the low pressure of a compressor; if the right end supplies high pressure, the left end is connected with the low pressure of the compressor; as long as the pressure difference between the left end and the right end reaches four kilograms, the inner piston moves and reverses direction. If the air conditioner compressor still works when the four-way valve is switched, the low-pressure is low, the high-pressure is high, the four-way valve is switched under the condition, the low-pressure end needs to be pressurized, the pressure cannot be quickly increased by more than four kilograms of high-pressure due to low pressure, so that the pressure difference required by the four-way valve cannot be formed, the four-way valve cannot normally work, the compressor is required to be stopped to balance the high-low pressure difference, and after the four-way valve is switched, the pressure is increased at one end, the pressure is reduced at the other end, and the pressure difference required by the four-way valve can be quickly reached. The reason why the cold storage and the low-temperature cold air are not used is that the working low-pressure of the cold storage is about four kilograms lower than that of the air conditioner, the throttling hole of the cold storage is smaller than the throttling hole of the air conditioner, and the temperature of the cold storage is lower, so that the low-pressure and high-pressure balance cannot be realized in a short time after the machine is stopped, the waiting time is long, the temperature in the cold storage can be influenced, and the reason why the four-way valve is not used for defrosting of the cold storage is that.

The existing defrosting methods of the refrigeration house comprise electric heating defrosting, water defrosting, high-pressure heat removal by a compressor and the like, the defrosting efficiency is low, the defrosting time is long, and the energy consumption is large. The energy consumption is large, the electricity generated by electric heating, water defrosting and defrosting by discharging heat of the compressor is converted into heat energy, and the heat energy is converted into the heat energy of one watt; the four-way valve used on the air conditioner has high heat fluorination defrosting efficiency, and because the heat pump of the air conditioner can change one watt of electric energy into three watts of heat energy, the defrosting efficiency is high; however, this efficient defrosting method cannot be used in a refrigerator because the characteristics of the four-way valve determine the requirements for the use of the air conditioner four-way valve. Therefore, how to make the four-way valve better cooperate with a refrigeration house and the like to meet the requirements of a low-temperature refrigeration house and low-temperature cold air defrosting is a problem to be solved urgently.

SUMMERY OF THE UTILITY MODEL

In order to solve the defects in the prior art, the utility model aims to provide a refrigeration and defrosting system, which can solve the problem that the refrigeration system needs to be shut down to switch a four-way valve for defrosting, so that the four-way valve can meet the requirements of the air conditioner for defrosting without shutting down, the defrosting time is shortened, and the requirements of a low-temperature refrigeration house and low-temperature cold air defrosting are met; and simultaneously, the problem of noise of air flow impact caused by the reversing of a four-way valve of an air conditioner is solved.

The utility model provides a technical scheme that its technical problem adopted does:

the refrigeration and defrosting system comprises a four-way valve, a condenser and an evaporator which are respectively communicated with the four-way valve, wherein the condenser and the evaporator are communicated through a pressure reduction pipeline;

the high-pressure exhaust pipe of the compressor conveys refrigerant to the four-way valve, and the refrigerant flows back to the compressor through the low-pressure suction pipe of the compressor;

and a pressure balance mechanism is connected between the high-pressure exhaust pipe and the pressure reduction pipeline.

Further, the pressure balance mechanism comprises a conveying pipeline connected with the high-pressure exhaust pipe, and a first balance electromagnetic valve is arranged on the conveying pipeline.

Furthermore, a first throttle valve is arranged on the pressure reducing pipeline.

Furthermore, the pressure balance mechanism also comprises a balance pipeline connected in parallel with the first throttle valve, and the balance pipeline is connected with the conveying pipeline.

Furthermore, a first one-way valve located on one side of the condenser and a second one-way valve located on one side of the evaporator are arranged on the balance pipeline.

Furthermore, a third one-way valve positioned on one side of the condenser and a second throttling valve positioned on one side of the evaporator are arranged on the pressure reducing pipeline.

Further, the pressure balancing mechanism further comprises a third throttle valve connected in parallel to two ends of the third one-way valve.

Further, the pressure balancing mechanism further comprises a second balancing solenoid valve connected in parallel to two ends of the second throttle valve.

Further, the conveying pipeline is communicated with a pipeline where the third throttle valve is located.

Compared with the prior art, the beneficial effects of the utility model reside in that:

1. the refrigeration and defrosting system of the example of the utility model can balance the pressure of the high-pressure section and the low-pressure section through the pressure balance system, so that the four-way valve can stably switch the directions without shutdown conversion, thereby the refrigeration system can meet the defrosting requirement and is suitable for refrigeration systems such as a refrigeration house;

2. the utility model discloses the refrigeration and the system of defrosting of example have reduced the air conditioner time of defrosting and the air conditioner room and have brought the poor problem of comfort level because of defrosting, have reduced switching-over air current noise simultaneously.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:

FIG. 1 is a schematic diagram of a refrigerating apparatus according to an embodiment;

FIG. 2 is a schematic diagram of the first balancing solenoid valve opened to balance high and low pressure differences in a refrigeration state according to the embodiment;

FIG. 3 is a schematic diagram illustrating a four-way valve switching from cooling to heating according to an embodiment;

FIG. 4 is a schematic view of the first embodiment of the present invention;

FIG. 5 is a schematic diagram of a first balanced solenoid valve opened to balance high and low pressure differences in a defrosting state;

FIG. 6 is a schematic diagram of a four-way valve switching from heating to cooling according to an embodiment;

FIG. 7 is a schematic view showing the structure of the second embodiment during cooling;

FIG. 8 is a schematic diagram of the second embodiment of the present invention showing the first balancing solenoid valve being opened to balance the high and low pressure differences;

FIG. 9 is a schematic diagram of a four-way valve of the second embodiment when switching from cooling to heating;

FIG. 10 is a schematic view of the second embodiment of the present invention;

FIG. 11 is a schematic diagram of the second embodiment of the present invention showing the first balancing solenoid valve being opened to balance the high and low differential pressures;

fig. 12 is a schematic diagram of switching a four-way valve from heating to cooling according to the second embodiment.

In the figure: the system comprises a compressor 1, a high-pressure exhaust pipe 1, a low-pressure air suction pipe 1-2, a four-way valve 2, a first interface 2-1, a second interface 2-2, a third interface 2-3, a fourth interface 2-4, a condenser 3, an evaporator 4, a pressure reduction pipeline 5, a first throttling valve 6, a balance pipeline 7, a first one-way valve 8, a second one-way valve 9, a first balance electromagnetic valve 10, a three-way valve 11, a delivery pipeline 12, a third one-way valve 13, a second throttling valve 14, a third throttling valve 15 and a second balance electromagnetic valve 16.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and are not limiting of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.

It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

The first embodiment is as follows:

as shown in fig. 1 to 6, the present embodiment provides a refrigeration and defrosting system, which includes a four-way valve 2, a condenser 3, an evaporator 4 and a compressor 1, the connection mode of each part is similar to that of an air-conditioning refrigeration system, and the principle is also similar to that of the air-conditioning refrigeration system, in addition, the refrigeration machine defrosting system of the present embodiment can also balance the pressure between the condenser 3 and the evaporator 4 through a pressure balancing mechanism.

Specifically, the four-way valve 2 is respectively communicated with a condenser 3 and an evaporator 4, the condenser 3 and the evaporator 4 are communicated through a pressure reduction pipeline 5, and a first throttle valve 6 is arranged on the pressure reduction pipeline 5. The four-way valve 2 comprises a first connector 2-1, a second connector 2-2, a third connector 2-3 and a fourth connector 2-4, the first connector 2-1 is communicated with a high-pressure exhaust pipe 1-1 of the compressor 1, and the third connector 2-3 is communicated with a low-pressure air suction pipe 1-2 of the compressor 1; the second interface 2-2 is communicated with the condenser 3, and the fourth interface 2-4 is communicated with the evaporator 4. When the air conditioner is in a refrigerating state, the first interface 2-1 is communicated with the second interface 2-2, and the third interface 2-3 is communicated with the fourth interface 2-4; when the defrosting device is in a defrosting state, the first connector 2-1 is communicated with the fourth connector 2-4; the second interface 2-2 is communicated with the third interface 2-3. The above connection method is similar to that of an air-conditioning refrigeration system, and will not be described herein.

In this embodiment, in order to balance the pipeline pressure in a short time and create conditions for the reversing of the four-way valve 2, so that the refrigeration system can meet the requirements of refrigeration and defrosting at the same time, the pressure reducing pipeline 5 is also connected in parallel with a balance pipeline 7, and the balance pipeline 7 can balance the pressure.

Specifically, the depressurization pipeline 5 is connected with the balance pipeline 7 through a three-way shunt valve 11, and the balance pipeline 7 is provided with a first one-way valve 8 located on one side of the condenser 3 and a second one-way valve 9 located on one side of the evaporator 4. The high-pressure exhaust pipe 1-1 is connected with a conveying pipeline 12, a first balance electromagnetic valve 10 is arranged on the conveying pipeline 12, in this embodiment, the conveying pipeline 12 is communicated with the balance pipeline 7, and the joint of the pipelines is also connected through a shunt three-way valve 11.

The principle of the system is as follows:

as shown in fig. 1, during normal refrigeration, the system works in the following manner:

as shown in fig. 1, normal cooling: the compressor 1 operates, high-pressure refrigerant is discharged to the four-way valve 2 through the high-pressure exhaust pipe 1-1, enters from the first interface 2-1 of the four-way valve 2 and flows out through the second interface 2-2, the high-pressure refrigerant flows into the condenser 3, the refrigerant after heat dissipation and cooling of the condenser 3 can be divided into a first one-way valve 8 and a first throttling valve 6, and the high-pressure refrigerant cannot pass through the first one-way valve 8 because the one-way valve is reversely cut off; the high-pressure refrigerant can be shunted to the second one-way valve 9 and the evaporator 4 after being cooled and decompressed by the first throttle valve 6, the second one-way valve 9 is cut off in the reverse direction, so the throttled refrigerant can only enter the evaporator 4, enters the four-way valve 2 after absorbing heat by the evaporator 4, flows in from the interface four 2-4 of the four-way valve 2 and flows out from the interface three 2-3, and finally returns to the compressor 1. The balance check valve is closed, so high-pressure refrigerant cannot be supplied to the check valve, the pressure of the balance pipeline 7 is low-pressure, and the check valve is in one-way conduction as long as the pressure is higher than the low-pressure, so the pressure of the section is always low-pressure as long as the first balance electromagnetic valve 10 is not opened.

As shown in fig. 2, when defrosting is ready to balance the high-low pressure difference: the compressor 1 runs, high-pressure refrigerant is discharged to the four-way valve 2 through the high-pressure exhaust pipe 1-1, enters from a first connector 2-1 of the four-way valve 2 and flows out through a second connector 2-2, the high-pressure refrigerant flows into the condenser 3, the refrigerant cooled by heat dissipation of the condenser 3 is sent to the first throttle valve 6, the first throttle valve 6 reduces pressure and temperature and then enters the evaporator 4, the evaporator 4 absorbs heat and then enters the four-way valve 2, the refrigerant flows in from a fourth connector 2-4 of the four-way valve 2 and flows out from a third connector 2-3, and finally the refrigerant returns to the compressor 1. At this time, the first balance solenoid valve 10 is opened, the high-pressure refrigerant flows to the two check valves through the delivery pipeline 12, and because the first check valve 8 is a connected high-pressure section, the pressure output by the first balance solenoid valve 10 is balanced at this point, and does not flow to this side; and the second check valve 9 is connected with a low-pressure section, at this time, after the first balance electromagnetic valve 10 is opened, the high-pressure refrigerant flows to the low pressure, the pressure of the low pressure is quickly raised due to the entrance of the high pressure, and the pressure of the evaporator 4 is raised to be in a state of being balanced with the pressure of the condenser 3 or having a smaller pressure difference, so as to prepare for reversing the four-way valve 2.

As shown in fig. 3, the four-way valve 2 commutates: the compressor 1 runs, high-pressure refrigerant is discharged to the four-way valve 2 through the high-pressure exhaust pipe 1-1 and enters from a first connector 2-1 of the four-way valve 2, because the four-way valve 2 changes direction and defrosts, the first connector 2-1 of the four-way valve 2 is communicated with a fourth connector 2-4, the high-pressure refrigerant flows to the evaporator 4 through the fourth connector 2-4, the high-pressure refrigerant is subjected to pressure reduction and temperature reduction through the first throttling valve 6 and then enters the condenser 3, and the condenser 3 flows to a third connector 2-3 through the second connector 2-2 and returns to the compressor 1. The first balancing solenoid valve 10 is now conductive or non-conductive, which has no effect on the process.

As shown in fig. 4, the four-way valve 2 successfully commutates: the first balance electromagnetic valve 10 is closed, at this time, the high-pressure high-temperature refrigerant in the evaporator 4 heats the frost outside the pipeline, the first balance electromagnetic valve 10 is closed, the compressor 1 runs, the high-pressure refrigerant is discharged from the high-pressure exhaust pipe 1-1 and is discharged to the four-way valve 2, and the four-way valve 2 reverses to defrost. At this time, the first interface 2-1 of the four-way valve 2 is communicated with the fourth interface 2-4, the high-pressure refrigerant flows to the evaporator 4 from the fourth interface 2-4 and then is divided into the second one-way valve 9 and the first throttling valve 6, and the second one-way valve 9 is cut off in the reverse direction, so the high-pressure refrigerant can only flow to the first throttling valve 6, and can be divided into the first one-way valve 8 and the condenser 3 after being depressurized and cooled by the first throttling valve 6. Because the first check valve 8 is cut off reversely, only the refrigerant flows to the condenser 3, and the condenser 3 flows from the interface two 2-2 to the interface three 2-3 to return to the compressor 1.

As shown in fig. 5, the defrosting and heating are finished and the cooling state is returned, so as to prepare for the switching of the four-way valve 2: the first balance electromagnetic valve 10 is opened, the compressor 1 runs, high-pressure refrigerant is discharged from a high-pressure exhaust pipe 1-1 and is discharged to the four-way valve 2, the high-pressure refrigerant flows to the evaporator 4 from a connector four 2-4 and then can be shunted to the second one-way valve 9 and the first throttling valve 6, the pressure at two ends of the second one-way valve 9 is balanced, so the high-pressure refrigerant can only flow to the first throttling valve 6, and the high-pressure refrigerant can flow to the first one-way valve 8 and the condenser 3 after being depressurized and cooled by the first throttling valve 6. Since the first check valve 8 is connected to the low pressure section, when the first balance solenoid valve 10 is opened, the high pressure refrigerant flows to the low pressure, the pressure of the low pressure refrigerant is rapidly increased due to the high pressure, and the pressure of the condenser 3 is increased to a state where the pressure is balanced with the pressure of the evaporator 4 or the pressure difference is small, thereby preparing for switching the four-way valve 2.

As shown in fig. 6, the four-way valve 2 is switched successfully, and then the first balancing solenoid valve 10 is turned off, and the cooling state is restored to the cooling state shown in fig. 1, and the next cycle is proceeded.

The second embodiment:

as shown in fig. 7-12, the present embodiment provides a refrigeration and defrosting system, which includes a four-way valve 2, a condenser 3, an evaporator 4 and a compressor 1, the connection relationship among the four-way valve 2, the condenser 3, the evaporator 4 and the compressor 1 in the present embodiment is the same as that in the first embodiment, and a pressure balancing mechanism is also provided in the present embodiment, the pressure balancing mechanism includes a conveying pipeline 12 connected to a high-pressure exhaust pipe 1-1, and a first balancing electromagnetic valve 10 is provided on the conveying pipeline 12.

Specifically, in this embodiment, the pressure reducing pipeline 5 is provided with a third check valve 13 located on the condenser 3 side and a second throttle valve 14 located on the evaporator 4 side. The pressure balancing mechanism further includes a third throttle valve 15 connected in parallel to both ends of the third check valve 13, and a second balancing solenoid valve 16 connected in parallel to both ends of the second throttle valve 14. Said delivery line 12 communicates with the line in which the third throttle 15 is located.

Similarly, the connections at the respective branch lines are also connected using the three-way shunt valve 11.

The principle of the system is as follows:

as shown in fig. 7, during normal refrigeration, the compressor 1 operates, the high-pressure refrigerant is discharged from the high-pressure exhaust pipe 1-1 to the four-way valve 2, enters from the first interface 2-1 of the four-way valve 2 and flows out through the second interface 2-2, flows into the condenser 3, is cooled by heat dissipation of the condenser 3, sequentially flows to the third one-way valve 13, the second throttle valve 14 and the evaporator 4, enters the four-way valve 2 after absorbing heat through the evaporator 4, flows into the fourth interface 2-4 of the four-way valve 2, flows out from the third interface 2-3, and finally returns to the compressor 1. Due to the resistance of the throttle, the refrigerant flows through the third check valve 13. At this time, the first and second balancing solenoid valves 10 and 16 are closed, and the refrigerant does not flow through the pressure balancing mechanism, so that the refrigerant is reciprocated to perform cooling.

As shown in fig. 8, when defrosting is ready to balance the high-low pressure difference: the compressor 1 operates, high-pressure refrigerant is discharged to the four-way valve 2 through the high-pressure exhaust pipe 1-1, enters from the first interface 2-1 of the four-way valve 2 and flows out through the second interface 2-2, and the high-pressure refrigerant flows into the condenser 3. At this time, the first and second balance solenoid valves 10 and 16 are opened, the high-pressure refrigerant flows to the third check valve 13 and the third throttle valve 15 through the delivery pipe 12, and the refrigerant mainly passes through the third check valve 13 due to the resistance of the throttle valve; the refrigerant flows to the second throttle valve 14 and the second solenoid valve again, and also because of the resistance of the throttle valve, the refrigerant mainly passes through the second solenoid valve, then flows to the evaporator 4, the evaporator 4 absorbs heat, then enters the four-way valve 2, flows into the interface four 2-4 of the four-way valve 2, flows out of the interface three 2-3, and finally returns to the compressor 1. Due to the addition of a refrigerant flow path, the pressure of the evaporator 4 is increased compared to normal refrigeration, and the pressure of the evaporator 4 is raised to a state of pressure equilibrium with the condenser 3 or a state of small pressure difference, so as to prepare for reversing the four-way valve 2.

As shown in fig. 9, the four-way valve 2 reverses: the compressor 1 runs, high-pressure refrigerant is discharged to the four-way valve 2 through the high-pressure exhaust pipe 1-1 and enters from a first interface 2-1 of the four-way valve 2, because the four-way valve 2 changes direction to defrost, at the moment, the first interface 2-1 of the four-way valve 2 is communicated with a fourth interface 2-4, the high-pressure refrigerant flows to the evaporator 4 from the fourth interface 2-4 and flows to a third throttle valve 15 (the third one-way valve 13 is not communicated in a reverse direction) through a second throttle valve 14 and a second balance electromagnetic valve 16, and because of the resistance of the second throttle valve 14, the refrigerant mainly passes through the second balance electromagnetic valve 16, is subjected to pressure reduction and temperature reduction and then enters the condenser 3, and the condenser 3 flows to a third interface 2-3 from the second interface 2-2 and then returns to the compressor 1. At this time, the unit cannot normally cool or heat, because the first and second balancing solenoid valves 10 and 16 are still on, and the condenser 3 and the evaporator 4 do not have a pressure difference.

As shown in fig. 10, the four-way valve 2 successfully commutates: the first balance electromagnetic valve 10 is closed, the second balance electromagnetic valve 16 is kept in a conducting state, high-pressure refrigerant is discharged from a high-pressure exhaust pipe 1-1 to the four-way valve 2 and enters from a first connector 2-1 of the four-way valve 2, because the four-way valve 2 changes direction to defrost, at the moment, the first connector 2-1 of the four-way valve 2 is communicated with a fourth connector 2-4, the high-pressure refrigerant flows to the evaporator 4 from the fourth connector 2-4, flows to the third throttle valve 5 (the third check valve 13 is not conducted in a reverse direction) from the second throttle valve 14 and the second balance electromagnetic valve 16, and mainly passes through the second balance electromagnetic valve 16 due to the resistance of the second throttle valve 14, and enters the condenser 3 after the pressure and temperature are reduced by the throttle valve 15, and the condenser 3 flows to the third connector 2-3 from the second connector 2-2 and returns to the compressor 1. A pressure difference is generated between the condenser 3 and the evaporator 4, so that the high-temperature and high-pressure refrigerant can be changed into the low-temperature and low-pressure refrigerant through the throttle valve to absorb and discharge heat.

As shown in fig. 11, the defrosting and heating are finished and the cooling state is returned, so as to prepare for switching the four-way valve 2: opening a first balance electromagnetic valve 10, wherein one flow path of the refrigerant is as follows: the compressor 1 runs, the high-pressure refrigerant is discharged from a high-pressure exhaust pipe 1-1 and discharged to a four-way valve 2, the high-pressure refrigerant flows to an evaporator 4 from a connector four 2-4 and then can be shunted to a second throttle valve 14 and a second balance electromagnetic valve 16, and mainly flows through the electromagnetic valves due to the resistance of the throttle valves, then flows to a third throttle valve 15 and a condenser, then flows to the four-way valve 2 and flows back to the compressor 1; the other flow path is as follows: from the feed line 12 to the condenser 3, the pressure in the condenser 3 is increased and the pressure difference between the condenser 3 and the evaporator 4 is reduced or equalized in preparation for switching the four-way valve 2.

As shown in fig. 12, the four-way valve 2 is successfully switched but normal cooling is not performed because the first and second balancing solenoid valves 10 and 16 are still turned on and the condenser 3 and the evaporator 4 do not perform a pressure difference. Then, the first and second balancing solenoid valves 10 and 16 are closed, and the cooling state shown in fig. 6 is restored, and the next cycle is performed.

It will be appreciated by those skilled in the art that the scope of the invention herein disclosed is not limited to the particular combination of features disclosed herein, and that other combinations of features disclosed herein or their equivalents, in any combination, are also encompassed by the invention without departing from the spirit of the invention. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims (9)

1. A refrigeration and defrosting system is characterized by comprising a four-way valve (2), a condenser (3) and an evaporator (4) which are respectively communicated with the four-way valve, wherein the condenser (3) and the evaporator (4) are communicated through a pressure reduction pipeline (5);

the refrigerant is conveyed into the four-way valve (2) by a high-pressure exhaust pipe (1-1) of the compressor (1), and the refrigerant flows back to the compressor (1) through a low-pressure suction pipe (1-2) of the compressor (1);

and a pressure balance mechanism is also connected between the high-pressure exhaust pipe (1-1) and the pressure reduction pipeline (5).

2. A refrigerating and defrosting system according to claim 1, characterized in that said pressure balancing means comprises a delivery line (12) connected to the high pressure exhaust line (1-1), said delivery line (12) being provided with a first balancing solenoid valve (10).

3. A refrigeration and defrost system as claimed in claim 2, characterized in that the depressurization line (5) is provided with a first throttle valve (6).

4. A refrigeration and defrost system as claimed in claim 3, characterized in that the pressure equalization means further comprise an equalization duct (7) connected in parallel to the first throttle valve (6), the equalization duct (7) being connected to the delivery duct (12).

5. Refrigeration and defrost system according to claim 4, characterized in that said balancing line (7) is provided with a first one-way valve (8) at the side of the condenser (3) and a second one-way valve (9) at the side of the evaporator (4).

6. A refrigeration and defrost system according to claim 2, characterized in that said depressurization line (5) is provided with a third one-way valve (13) on the side of the condenser (3) and a second throttle valve (14) on the side of the evaporator (4).

7. A refrigeration and defrost system according to claim 6, wherein said pressure balancing mechanism further comprises a third throttle valve (15) connected in parallel across said third one-way valve (13).

8. A refrigeration and defrost system according to claim 7, characterized in that the pressure balancing mechanism further comprises a second balancing solenoid valve (16) connected in parallel across the second throttle valve (14).

9. A refrigeration and defrost system as claimed in claim 8, characterized in that the delivery line (12) communicates with the line where the third throttle valve (15) is located.

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