JPH03267663A - Operating method for refrigerator - Google Patents

Abstract

PURPOSE:To prevent the pressure of refrigerant gas to be discharged from a compressor from excessively rising by feeding a part of the gas discharged from the compressor to a condenser when the pressure of the gas discharged from the compressor exceeds a predetermined value, dissipating heat from the condenser, and then introducing the residue into an evaporator. CONSTITUTION:A pressure switch 40 for sensing the pressure of refrigerant gas discharged from a compressor 1 is provided in a discharge tube 1a of the compressor 1. When the pressure sensed by the switch 40 is a predetermined value or less, a solenoid valve 2 remains closed, while when it exceeds the value, the valve 2 is opened. Then the pressure of the gas discharged from the compressor 1 is lower than a predetermined value, i.e., a pressure set by the switch 40, under a state where a load is cooled by a first evaporator 8 and heated by a second evaporator 11, solenoid valves 6, 18, 20 are opened, and the valves 2, 9, 17, 21 are closed. Thus, the gas of high temperature and high pressure discharged from the compressor 1 is introduced to the evaporator 1 through a bypass tube 31 and the valve 18 to heat the load in the step of passing the evaporator 11 to be condensed and liquefied.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method of operating a refrigeration system suitable for a refrigerating vehicle or the like having two refrigerators or heat-insulating compartments.

(Prior Art) The present applicant is currently applying for a patent regarding the refrigeration system and its operating method shown in FIG.

This refrigeration system includes a compressor 1, a condenser 3 connected to the outlet of the compressor 1, and first and second evaporators 8.11 connected in parallel to the outlet of the condenser 3. Bypass pipes 30.31 connecting the inlets of these evaporators 8.11 and the discharge ports of the pressure machine 1, respectively, and the evaporators 8.11
first and second return pipes 32.33 connecting the outlet of the condenser 3 and the outlet of the condenser 3, respectively, and a refrigerant that is interposed in each of these return pipes 32.33 and allows only the flow of refrigerant toward the outlet of the condenser 3. It is equipped with check valves 22 and 23.

Table 1 shows the relationship between the operation of each evaporator 8.11 of this refrigeration system and the opening/closing of the solenoid valve.

When cooling is applied to both evaporators 8 and 11 in Table 1, as shown in case l of Table 1, solenoid valves 2.6.9.
20.21 is opened, and solenoid valves 17.18 are closed.

The high-temperature, high-pressure refrigerant gas discharged from the compressor 1 passes through the electromagnetic valve 2 and enters the condenser 3, where it is condensed and liquefied by dissipating heat. This liquid refrigerant is branched through a receiver 4 and a check valve 5, one of which is branched through a solenoid valve 6 and a first branch.
The refrigerant gas enters the expansion valve 7, where it is throttled and adiabatically expanded, enters the first evaporator 8, where it is evaporated by cooling the load, and then this refrigerant gas passes through the solenoid valve 20 and the reverse It flows through the stop valve 12.

The other branched liquid refrigerant passes through the magnetic valve 9 and enters the second expansion valve 10, where it is throttled and expanded adiabatically, and then enters the second evaporator 11, where it cools the load. The refrigerant gas passes through the electromagnetic valve 21 and has its flow rate adjusted by the refrigerant flow rate adjustment valve 14, and then passes through the check valve 15 where the refrigerant gas that has passed through the check valve 12 It joins with the gas and enters the accumulator 13, where the unevaporated liquid refrigerant is separated. After that, it enters the suction pressure regulating valve 16, where the pressure is adjusted, and then the compressor 1
is inhaled and compressed again.

When heating both evaporators 8 and -11, as shown in case 2 of Table 1, the solenoid valve 17.1
8.20.21 is open and solenoid valve 2.6.9 is closed.

In this way, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 is branched immediately after discharge, one of which enters the first evaporator 8 through the bypass pipe 30 and the solenoid valve 17 installed therein. After cooling down by heating the load here,
It flows through the electromagnetic valve 20 and the check valve 12. The other branched refrigerant gas is connected to the bypass pipe 31 and the solenoid valve 1 installed therein.
8, enters the second evaporator 11, where the load is cooled down by heating, and then passes through the magnetic valve 21, the refrigerant flow rate adjustment valve 14, and the check valve 15, where the check valve 12 is closed. It joins with the refrigerant gas that has passed through, and is sucked into the compressor 1 via the accumulator 13 and the suction pressure regulating valve 16.

When the first evaporator 8 cools the load and the second evaporator 11 heats the load, the solenoid valve 6.18.20 opens and the solenoid valve 6.18.20 opens, as shown in case 3 of Table 1. Valve 2.9.7.
21 is closed.

In this way, the high temperature and high pressure refrigerant gas discharged from the compressor 1 passes through the bypass pipe 31 and the solenoid valve 18 to the second evaporator 1.
1, where it condenses and liquefies by heating the load in the process of flowing through it. Next, this refrigerant liquid passes through the second return pipe 33, the check valve 23, the electromagnetic valve 6, and the first expansion valve 7, and enters the first evaporator 8, where it is evaporated and vaporized by cooling the load. Thereafter, it returns to the compressor 1 via the solenoid valve 20, check valve 12, accumulator 13, and suction pressure regulating valve 16.

When the load is heated by the first evaporator 8 and the load is cooled by the second evaporator 11, as shown in case 4 of Table 2, the solenoid valve 9.17.21 is opened and the solenoid valve 9.17.21 is opened. Valve 2.6.18
．． 20 is considered closed.

Thus, the high temperature and high pressure refrigerant gas discharged from the compressor 1 passes through the bypass pipe 30 and the solenoid valve 17 to the first evaporator 8.
where it condenses and liquefies by heating the load. This refrigerant liquid then passes through the first return pipe 32 and the check valve 2.
2, the second evaporator 1 via the solenoid valve 9 and the second expansion valve 10
1, and after the load is evaporated by cooling it, the solenoid valve 2], the refrigerant flow rate adjustment valve 14, and the check valve 15
, the accumulator 13, and the suction pressure regulating valve 16 before returning to the compressor 1.

(Problem to be Solved by the Invention) When heating a load with one of the evaporators and cooling the load with one of the other evaporators, the amount of heat dissipated in one of the evaporators is insufficient. There was a problem in that the pressure of the discharged refrigerant gas increased excessively, and as a result, the operation of the refrigeration system could not be continued stably.

(Means for Solving the Problems) The present invention was invented in order to solve the above problems, and the gist of the present invention is to provide a compressor and an aII device connected to the discharge port of the compressor. and a plurality of evaporators connected in parallel to the outlet of the condenser, a plurality of bypass pipes respectively connecting the inlets of the plurality of evaporators and the discharge port of the compressor, and a plurality of bypass pipes of the plurality of evaporators. A refrigeration system comprising a plurality of return pipes connecting the outlet and the outlet of the condenser, and a check valve that is interposed in each of the return pipes and allows only the flow of refrigerant toward the outlet of the condenser, The high-temperature, high-pressure refrigerant gas discharged from the compressor was introduced into some of the plurality of evaporators through a bypass pipe to heat the load, and the gas was passed through some of the evaporators. When the refrigerant is introduced into the remaining evaporator through the return pipe and check valve to cool the load, when the pressure of the refrigerant gas discharged from the compressor exceeds a predetermined value, the refrigerant gas discharged from the compressor A method of operating a refrigeration apparatus is characterized in that a part of the refrigerant gas is introduced into the remaining evaporator through the condenser.

(Function) In the present invention, when a load is heated by some of the evaporators and the load is cooled by the remaining evaporators, the pressure of the refrigerant gas discharged from the compressor is set to a predetermined value. When the refrigerant gas is exceeded, a part of the refrigerant gas discharged from the compressor flows into the condenser where the heat is radiated, and then the remaining part is introduced into the evaporator.

(Example) One embodiment of the invention is shown in FIG.

The discharge pipe 1a of the compressor 131 is provided with a pressure switch 4o that detects the pressure of the refrigerant gas discharged from the compressor 1, and when the pressure detected by the pressure switch 40 is below a predetermined value, The solenoid valve 2 is kept closed, and when a predetermined value is exceeded, the solenoid valve 2 is opened.

The rest of the structure is the same as the conventional one shown in FIG. 2, and corresponding members are given the same reference numerals.

The relationship between the action of each evaporator 8.11 and the opening and closing of each valve is shown in Table 2.

When cooling the load with generators 8 and 11 in both Table 2, that is,
When heating the load with case 1 and both evaporators 8 and 11, case 2 is similar to the conventional one shown in FIG.

When the load is cooled by the first evaporator 8 and the load is heated by the second evaporator 11, the pressure of the refrigerant gas discharged from the compressor l is set to a predetermined value, that is, the pressure switch 40. When the pressure is lower than the set pressure, as shown in the upper row of case 3 in Table 2, the solenoid valve 6.18.20 opens;
Magnetic valve 2.9.17.21 is closed.

In this way, the high temperature and high pressure refrigerant gas discharged from the compressor 1 passes through the bypass pipe 31 and the solenoid valve 18 to the second generator 1.
1, and in the process of flowing through this, the load is heated and condensed into liquid. Next, this refrigerant liquid passes through the second return pipe 33, the check valve 23, the solenoid valve 6, and the first expansion valve 7, and enters the first evaporator 8, where it is evaporated by cooling the load. After that, the compression Ill passes through the solenoid valve 20, the check valve 12, the accumulator 13, and the suction pressure regulating valve 16.
Return to

When the pressure of the refrigerant gas discharged from the compressor 1 exceeds the set pressure of the pressure switch 40, as shown in the lower row of case 3 in Table 2, the magnetic valve 2, 6, 18, 20 opens 1. , the magnetic valve 9.17.21 is closed.

In this way, the refrigerant gas discharged from the compressor 1 branches immediately after discharge, and a part of it passes through the 'am valve 2 and enters the condenser 3, where it is condensed and liquefied by dissipating heat. Most of the zero-branched refrigerant gas flowing through the valve 5 passes through the bypass pipe 31, the magnetic valve 18, the second evaporator 11, the second return pipe 33, and the check valve 23, and then returns to the previously branched refrigerant gas. through the TH, M1 valve 6, the first expansion valve 7, the first evaporator 8, the solenoid valve 20, the check valve 12, the accumulator 13, the suction pressure regulating valve 16, and the compressor 1. Return to

As a result, the refrigerant circulating in the refrigerant circuit radiates heat in the condenser 2 and also in the second evaporator 11, increasing the amount of heat radiated, so the pressure of the refrigerant gas discharged from the compressor 1 decreases. When this pressure falls below the set pressure of the pressure switch 40, the solenoid valve 2 closes again, and the operation shown in the upper part of the case 3 is performed.

When the first evaporator 8 heats the load and the second evaporator 11 cools the load, if the pressure of the refrigerant gas discharged from the compressor 1 is lower than the set pressure of the pressure switch 40, the second Case 4 is shown in the upper row of the table, and the case where the pressure is higher than the set pressure is shown in the lower row, and since it is similar to case 3 above, the explanation thereof will be omitted.

Although the above description has specifically been given of an apparatus equipped with two evaporators 8.11, it goes without saying that the present invention can also be applied to an apparatus equipped with two or more evaporators.

(Effects of the Invention) In the present invention, a load is heated by introducing high-temperature, high-pressure refrigerant gas discharged from a compressor into some of the plurality of evaporators through a bypass pipe. When the pressure of refrigerant gas discharged from the compressor exceeds a predetermined value when the refrigerant that has passed through the first evaporator is introduced into the second evaporator through the return pipe and check valve to cool the load. Since a part of the refrigerant gas discharged from the compressor is introduced into the remaining evaporator through the condenser, the pressure of the refrigerant gas discharged from the compressor can be maintained below a predetermined value, and therefore the refrigeration system This makes it possible to continue stable operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a refrigerant circuit diagram showing one embodiment of the present invention, and FIG. 2 is a refrigerant circuit diagram of a conventional refrigeration system. Compressor-1, condenser-3, evaporator-8, 11, bypass pipe 30.31, return pipe-32, 33, check valve-22,
−3(

Claims (1)

[Claims] a compressor; a condenser connected to a discharge port of the compressor;
a plurality of evaporators connected in parallel to the outlet of this condenser;
a plurality of bypass pipes respectively connecting the inlets of the plurality of evaporators and the outlet of the compressor; a plurality of return pipes connecting the outlet of the plurality of evaporators and the outlet of the condenser; In a refrigeration system equipped with a check valve that is interposed in each pipe and allows refrigerant to flow only toward an outlet of the condenser, the refrigerant is discharged from the compressor to some of the evaporators of the plurality of evaporators. The high-temperature, high-pressure refrigerant gas is introduced through the bypass pipe to heat the load, and the refrigerant that has passed through some of the evaporators is introduced into the remaining evaporators through the return pipe and check valve. When cooling the load, when the pressure of the refrigerant gas discharged from the compressor exceeds a predetermined value, a part of the refrigerant gas discharged from the compressor is introduced into the remaining evaporator via the condenser. A method of operating a refrigeration system characterized by: