JP5625587B2 - Refrigerant circuit device - Google Patents

Description

  The present invention relates to a refrigerant circuit device, and more particularly, to a refrigerant circuit device applied to a vending machine that sells products such as canned beverages and beverages containing plastic bottles.

  Conventionally, for example, a refrigerant circuit device applied to a vending machine that sells products such as canned beverages and beverages in plastic bottles, an evaporator, a compressor, a condenser, and an electronic expansion valve are sequentially connected by a refrigerant pipe to form an annular shape. A refrigerant circuit configured as described above is provided. The evaporator is disposed inside each commodity storage. The compressor sucks the refrigerant that has passed through the evaporator, compresses the sucked refrigerant, and discharges it in a high-temperature and high-pressure state. The condenser introduces and condenses the refrigerant compressed by the compressor. The electronic expansion valve is provided on the upstream side of each evaporator, decompresses the refrigerant condensed in the condenser, adiabatically expands it, and supplies it to the downstream evaporator.

  In such a refrigerant circuit device, the refrigerant compressed by the compressor is condensed by the condenser, and the condensed refrigerant is adiabatically expanded by the electronic expansion valve and evaporated by the evaporator. The refrigerant evaporated in the evaporator is sucked by the compressor, compressed again, and circulated. As a result, the internal air of the commodity storage box in which the evaporator is disposed is cooled.

  As the above-mentioned electronic expansion valve, there is known an electronic expansion valve that uses a stepping motor to change the opening degree of the expansion passage to adjust the degree of expansion of the refrigerant. However, such an electronic expansion valve is expensive because it uses a stepping motor. In some cases, the cost may increase. Therefore, an inexpensive pulse-driven expansion valve that adjusts the degree of expansion of the refrigerant by opening and closing the inlet of the expansion passage with an electromagnetic valve is known (for example, see Patent Document 1).

  Such a pulse drive type expansion valve (electronic expansion valve) includes a valve body provided with a refrigerant inlet and a refrigerant outlet, and is disposed inside the valve body and has a smaller diameter than the refrigerant inlet and is provided at the refrigerant outlet. A valve seat having a small-diameter channel communicating therewith, and a valve body that opens and closes the inlet of the small-diameter channel by moving in a manner of approaching and separating from the valve seat inside the valve body. In such an electronic expansion valve, the inlet of the small-diameter channel is opened and closed by moving the valve body at a predetermined valve opening / closing ratio (duty ratio), and the refrigerant flowing through the refrigerant inlet is adiabatically expanded in the small-diameter channel. To flow out through the refrigerant outlet.

Japanese Patent Laid-Open No. 53-1352

  In such a refrigerant circuit device to which the electronic expansion valve proposed in Patent Document 1 is applied, all the electronic expansion valves may be fully closed depending on the evaporation temperature of the refrigerant in the evaporator. Thus, if the compressor is continuously driven for a predetermined time while all the electronic expansion valves are in the fully closed state, the refrigerant sucked by the compressor is reduced, thereby overloading the compressor. This will cause damage to the compressor and increase in power consumption.

  An object of this invention is to provide the refrigerant circuit apparatus which can suppress the failure | damage of a compressor and the increase in power consumption in view of the said situation.

In order to achieve the above object, a refrigerant circuit device according to claim 1 of the present invention is provided with an evaporator that is disposed in each chamber and evaporates the refrigerant passing through the chamber, and sucks the refrigerant evaporated in the evaporator A compressor that compresses the refrigerant, a condenser that condenses the refrigerant compressed by the compressor, and a small-diameter flow that adiabatically expands the refrigerant condensed by the condenser. The refrigerant pipe has a passage and an electronic expansion valve having a valve body that allows or restricts the passage of the refrigerant through the small-diameter channel by reciprocating itself to open and close the inlet of the small-diameter channel. The ratio of the valve opening time to the operating cycle of each electronic expansion valve is determined as the valve opening / closing ratio from the evaporation temperature of the evaporator in the chamber that needs to be cooled according to a predetermined time schedule. Drive target For the first priority expansion valve arbitrarily selected from among the electronic expansion valves, the valve closing time is set in advance and is determined as the allowable drive time of the compressor when all the electronic expansion valves are in the fully closed state. Drive with an operation cycle corresponding to the valve opening / closing ratio in a mode that is less than the valve closing limit time, and for other electronic expansion valves, operation according to the valve opening / closing ratio within a predetermined operating cycle upper limit time range It is characterized by comprising control means for driving in a cycle.

  The refrigerant circuit device according to a second aspect of the present invention is the refrigerant circuit device according to the first aspect, wherein the control means sets the electronic expansion valve having the smallest valve opening / closing ratio as a first priority expansion valve. To do.

  According to a third aspect of the present invention, there is provided the refrigerant circuit device according to the first aspect, wherein the control means sets the electronic expansion valve having the smallest cumulative valve opening / closing frequency as the first priority expansion valve. To do.

  According to a fourth aspect of the present invention, there is provided the refrigerant circuit device according to any one of the first to third aspects, wherein the control means is the electronic expansion valve having the smallest valve opening / closing ratio at the time of the previous valve opening / closing ratio determination. Is set as the first priority expansion valve, the electronic expansion valve having the second smallest valve opening / closing ratio is set as the first priority expansion valve when the next valve opening / closing decision is made.

  According to the refrigerant circuit device of the present invention, the control means determines the valve opening / closing ratio of each electronic expansion valve from the evaporation temperature of the evaporator of the chamber that needs to be cooled according to a predetermined time schedule, and the electronic expansion valve to be driven For the first priority expansion valve selected arbitrarily, the valve closing time is less than the valve closing limit time determined as the allowable driving time of the compressor when all the electronic expansion valves are fully closed. The other electronic expansion valves are driven at an operation cycle according to the valve opening / closing rate within a predetermined operating cycle upper limit time range, so that all the electronic expansion valves are operated. The time for the fully closed state can be made shorter than the valve closing limit time. As a result, it is possible to control the drive timing of each electronic expansion valve so that the time for which all the electronic expansion valves are fully closed does not exceed a certain time, resulting in damage to the compressor and increase in power consumption. There exists an effect that it can control.

FIG. 1 is an explanatory diagram showing a circuit configuration of a refrigerant circuit device according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the configuration of the electronic expansion valve shown in FIG. FIG. 3 is a cross-sectional view taken along line AA in FIG. FIG. 4 is a longitudinal sectional view showing the opened state of the electronic expansion valve shown in FIG. FIG. 5 is a block diagram schematically showing a characteristic control system of the refrigerant circuit device shown in FIG. FIG. 6 is a flowchart for explaining the processing contents of the electronic expansion valve drive processing executed by the control means shown in FIG. 5 according to a predetermined time schedule. FIG. 7 is a flowchart showing the processing contents of the first priority expansion valve setting process in the electronic expansion valve drive process shown in FIG.

  Exemplary embodiments of a refrigerant circuit device according to the present invention will be explained below in detail with reference to the accompanying drawings.

  FIG. 1 is an explanatory diagram showing a circuit configuration of a refrigerant circuit device according to an embodiment of the present invention. The refrigerant circuit device illustrated here is applied to, for example, a vending machine that sells canned beverages, plastic bottled beverages, and the like, and includes a refrigerant circuit 10 in which a refrigerant (for example, R134a) is sealed. Yes. The refrigerant circuit 10 is configured by sequentially connecting a compressor 11, a condenser 12, and an evaporator 13 through a refrigerant pipe 14.

  The compressor 11 is disposed in the machine room of the vending machine, although not explicitly shown in the drawing. The machine room is a room inside the main body cabinet, which is the main body of the vending machine, and is divided into a plurality of product storages 1, 2, 3, and below the product storages 1, 2, 3. The compressor 11 sucks the refrigerant through the suction port, compresses the sucked refrigerant to be in a high-temperature and high-pressure state (high-temperature and high-pressure refrigerant), and discharges it from the discharge port.

  The condenser 12 is disposed in the machine room like the compressor 11. When the refrigerant compressed by the compressor 11 passes, the condenser 12 condenses the refrigerant.

  A plurality of evaporators 13 (three in the illustrated example) are provided, and are disposed inside each of the commodity containers 1, 2, 3. The refrigerant pipe 14 connecting the evaporator 13 and the condenser 12 is branched into three at a branch point P1 in the middle of the refrigerant pipe 14, and on the inlet side of the evaporator 13 disposed in the right product storage case 1, It is connected to the inlet side of the evaporator 13 disposed in the central commodity storage 2 and to the inlet side of the evaporator 13 disposed inside the left commodity storage 3.

  In the refrigerant pipe 14, an electronic expansion valve 20 is provided on the way from the branch point P1 to each evaporator 13. The electronic expansion valve 20 is a variable flow rate whose opening can be adjusted in accordance with a command given from the control means 50 described later, and can be in a fully closed state. The electronic expansion valve 20 is for adiabatically expanding by reducing the pressure of the refrigerant passing therethrough. The configuration of the electronic expansion valve 20 will be described later.

  The refrigerant pipe 14 connected to the outlet side of the evaporator 13 joins at a midway junction P2 and is connected to the compressor 11 via the accumulator 15. Here, the accumulator 15 is gas-liquid separation means for storing the liquid-phase refrigerant and allowing the gas-phase refrigerant to pass through when the refrigerant passing therethrough is a gas-liquid mixed refrigerant. In addition, the code | symbol F1 and F2 in FIG. 1 are an internal fan and an external fan, respectively.

  In the refrigerant circuit 10 having the above-described configuration, the refrigerant compressed by the compressor 11 reaches the condenser 12 and dissipates heat to the ambient air (outside air) while passing through the condenser 12 to condense. The refrigerant condensed in the condenser 12 (gas-liquid two-phase refrigerant) branches into three at the branch point P1, and then adiabatically expands in the electronic expansion valve 20, reaches each evaporator 13, and evaporates in each evaporator 13. Then, heat is taken from the internal air of the product containers 1, 2, and 3 to cool the internal air. The cooled internal air circulates in the interior by driving each internal blower fan F1, whereby the products stored in each product storage 1, 2, 3 are cooled to the circulating internal air. The refrigerant evaporated in each evaporator 13 merges at the merge point P2, and then is sucked into the compressor 11 and compressed by the compressor 11 to repeat the above-described circulation.

  The structure of the electronic expansion valve 20 will be described with reference to FIGS. 2 is a longitudinal sectional view showing the configuration of the electronic expansion valve shown in FIG. 1, and FIG. 3 is a sectional view taken along line AA in FIG. The electronic expansion valve 20 exemplified here includes a valve main body 20 a, an armature 30, and a solenoid 40.

  The valve main body 20 a is a housing composed of a valve body upper part 21 and a valve body lower part 22. The valve body upper portion 21 is a cylindrical member made of a ferromagnetic material, and has an inflow portion 211, a suction portion 212, an upper vertical hole 213, and a horizontal hole 214. The inflow part 211 is provided in the upper part of the valve body upper part 21, and accept | permits insertion of the edge part of the refrigerant | coolant piping 14 connected with the condenser 12 via the branch point P1. The suction part 212 is, for example, a yoke, and sucks the armature 30 when a magnetic force acts. The upper vertical hole 213 extends along the central axis of the valve body upper portion 21 and communicates with the refrigerant pipe 14 inserted into the inflow portion 211. A communication portion between the upper vertical hole 213 and the refrigerant pipe 14 constitutes a refrigerant inlet. The lateral hole 214 extends along the horizontal direction while communicating with the upper longitudinal hole 213 at the lower end portion of the upper longitudinal hole 213, and communicates with the valve body interior 20b.

  The valve body lower part 22 is a columnar member made of a ferromagnetic material like the valve body upper part 21. The valve body lower part 22 defines an internal space (valve body interior 20b) between the valve body upper part 21 via a spacer 23, and a valve body side part 24, which is a cylindrical member made of a nonmagnetic material, is formed. The valve body upper part 21 and the center axis of each other are engaged with each other in such a manner that they are on the same straight line.

  The valve body lower part 22 has an outflow part 221, a valve seat 222, and a lower vertical hole 223. The outflow part 221 is provided in the lower part of the valve body lower part 22, and allows the end of the refrigerant pipe 14 connected to the evaporator 13 to be inserted.

  The valve seat 222 is disposed in a storage space 224 defined above the outflow portion 221. The valve seat 222 is a cylindrical member made of a non-magnetic material, and has a small-diameter channel 2221 extending along the vertical direction. The small-diameter channel 2221 is a refrigerant inlet, that is, a channel having a smaller diameter than the inner diameter of the upper vertical hole 213 and the refrigerant pipe 14, and has openings on the upper surface and the lower surface of the valve seat 222. Here, the opening on the upper surface side of the valve seat 222 becomes the refrigerant inlet 2221a, and the opening on the lower surface side becomes the refrigerant outlet 2221b.

  The lower vertical hole 223 extends along the central axis of the valve body lower portion 22, and the upper end communicates with the small-diameter flow path 2221 of the valve seat 222 and the lower end is connected to the refrigerant pipe 14 inserted into the outflow portion 221. It communicates. The communication portion between the lower vertical hole 223 and the refrigerant pipe 14 constitutes a refrigerant outlet, and the small diameter flow path 2221 of the valve seat 222 communicates with the refrigerant outlet through the lower vertical hole 223.

  The armature 30 is made of a ferromagnetic material and is a three-stage cylindrical member having three different outer diameters. The armature 30 has a suction part 31, a side part 32, and a valve body 33. The adsorption part 31 is the uppermost part and has a flat upper end surface. The side part 32 is a part having the maximum diameter, and maintains a sufficient gap with the storage space 224 defined by the valve body lower part 22 of the valve body 20a. The valve body 33 is the lowest part and has a flat lower end surface.

  In such an armature 30, a disc spring 34 is fixed to the upper end surface of the side portion 32 by caulking. The disc spring 34 is fixed to the valve body lower portion 22 through a pin 342 at the periphery of the disc-shaped main body portion 341. As shown in FIG. 3, the disc spring 34 has a center hole 343 for inserting and engaging the suction portion 31 of the armature 30 at the center thereof, and is spirally formed at an equal pitch. The slit 344 is formed. Since the slits 344 are formed in the main body portion 341 at four equal pitches, the disc springs 34 are highly linear in the axial direction (vertical direction) and have high rigidity in the radial direction. Further, a groove 321 serving as a refrigerant passage is formed on the peripheral surface of the side portion 32 of the armature 30.

  The armature 30 is always urged toward the direction close to the valve seat 222 by the restoring force of the disc spring 34, and the lower end surface of the valve body 33 abuts on the upper end surface of the valve seat 222 to flow. The inlet 2221a will be closed. When the armature 30 is urged by the disc spring 34 and the lower end surface of the valve body 33 comes into contact with the upper end surface of the valve seat 222, the upper end surface of the suction portion 31 and the suction portion 212 of the upper portion of the valve body 21. A gap is formed between the lower surface of the substrate.

  The solenoid 40 is for making a magnetic force act on the valve body 20a, and is composed of an iron core 41 and a coil 42. Such a solenoid 40 is attached to the side of the valve main body 20a via the fixtures 43a and 43b. More specifically, the upper portion and the lower portion of the solenoid 40 have screw portions (not shown) that pass through the through holes (not shown) of the fixing fittings 43a and 43b, and pass through the fixing fittings 43a and 43b. By tightening the threaded portion with the nut 44, the solenoid 40 is fixed to the fixing brackets 43a and 43b. The fixing brackets 43a and 43b are flat plate members made of a ferromagnetic material, and both ends of the plane are formed in a semicircular shape. The valve body upper portion 21 and the valve body lower portion 22 of the valve body 20a are also screwed. Is fixed. Thereby, the solenoid 40 is attached to the side of the valve main body 20a via the fixtures 43a and 43b.

  Magnetic flux generated from the coil 42 by energizing the solenoid 40 flows through a magnetic circuit that returns to the iron core 41 from the iron core 41, the fixture 43a, the valve body lower portion 22, the armature 30, the valve body upper portion 21, and the fixture 43b. As a result, a magnetic force is applied to the valve body 20a.

  Then, when the magnetic flux flows through the magnetic circuit by energization of the solenoid 40, the armature 30 is attracted to the attracting portion 212, and the armature 30 receives the urging force of the disc spring 34 as shown in FIG. 4. The armature 30 moves toward the direction away from the valve seat 222, that is, upward, and the suction portion 31 of the armature 30 is attracted to the suction portion 212, so that a gap is formed between the valve body 33 and the valve seat 222. The

  When the gap is formed between the valve body 33 and the valve seat 222 in this way, the refrigerant (condensed refrigerant) flowing from the refrigerant pipe 14 inserted into the inflow portion 211 is indicated by an arrow in FIG. In addition, it enters the gap via the upper vertical hole 213, the horizontal hole 214, the valve body inside 20b, the slit 344 of the disc spring 34, and the groove 321 of the armature 30, and flows into the small diameter flow path 2221 from the inlet 2221a. It is adiabatically expanded and becomes a gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant reaches the refrigerant pipe 14 inserted into the outflow portion 221 from the outlet 2221b through the lower vertical hole 223, and is supplied to the evaporator 13 through the refrigerant pipe 14. .

  FIG. 5 is a block diagram schematically showing a characteristic control system of the refrigerant circuit device shown in FIG. As shown in FIG. 5, the refrigerant circuit device includes refrigerant temperature sensors S <b> 1 to S <b> 3, interior temperature sensors S <b> 4 to S <b> 6, and control means 50.

  The refrigerant temperature sensors S <b> 1 to S <b> 3 are disposed in the refrigerant pipe 14 near the inlet of each evaporator 13, and detect the refrigerant temperature supplied to the evaporator 13, that is, the evaporation temperature. The refrigerant temperature (evaporation temperature) detected by the refrigerant temperature sensors S1 to S3 is given to the control means 50 as a refrigerant temperature signal.

  The inside temperature sensors S4 to S6 are disposed inside the respective product storages 1, 2, and 3 and detect the inside temperature. The internal temperature detected by the internal temperature sensors S4 to S6 is given to the control means 50 as an internal temperature signal.

  The control means 50 controls the drive of the compressor 11 and the electronic expansion valve 20 according to programs and data stored in advance in the memory 60, and includes a compressor drive control unit 51 and an electronic expansion valve drive control unit 52. ing.

  Here, the memory 60 stores various types of information necessary for the control means 50 to execute processing in addition to the above-described programs. For example, cooling temperature information, valve closing limit time information, and operation cycle upper limit time information are stored. The cooling temperature information includes a cooling start temperature that is a drive start temperature of the compressor 11 and a cooling stop temperature that is a drive stop temperature of the compressor 11. The valve closing limit time information includes a valve closing limit time (for example, 20 seconds) determined from an allowable range such as pressure fluctuation in the compressor 11. This valve closing limit time is determined as the allowable drive time of the compressor when all the electronic expansion valves 20 are fully closed. The operation cycle upper limit time information includes the operation cycle upper limit time (for example, 60 seconds) of the electronic expansion valve 20.

  When the internal temperature detected by the internal temperature sensors S4 to S6 exceeds the cooling start temperature included in the cooling temperature information, the compressor drive control unit 51 drives the compressor 11 while the internal temperature is detected. When the temperature is lower than the cooling stop temperature, the compressor 11 is stopped.

  The electronic expansion valve drive control unit 52 includes an input processing unit 521, a valve opening / closing ratio determination unit 522, a first priority expansion valve setting unit 523, an operation cycle calculation unit 524, and an output processing unit 525. The input processing unit 521 inputs a refrigerant temperature signal given from the refrigerant temperature sensors S1 to S3, that is, an evaporation temperature.

  The valve opening / closing ratio determining unit 522 determines whether to drive and stop driving each electronic expansion valve 20 from the evaporation temperature input through the input processing unit 521. The ratio of time (valve opening time) is determined.

  The first priority expansion valve setting unit 523 sets the first priority expansion valve from the duty ratio determined through the valve opening / closing ratio determination unit 522. More specifically, the first priority expansion valve setting unit 523 sets the duty ratio to 2 when the electronic expansion valve 20 having the smallest duty ratio is set as the first priority expansion valve at the time of the previous valve opening / closing ratio determination. While the second smallest electronic expansion valve 20 is set as the first priority expansion valve, in other cases, the electronic expansion valve 20 having the smallest duty ratio is set as the first priority expansion valve.

  The operation cycle calculation unit 524 calculates the operation cycle of the electronic expansion valve 20 to be driven based on the duty ratio determined through the valve opening / closing ratio determination unit 522 and the setting result of the first priority expansion valve setting unit 523. It is. The output processing unit 525 outputs a drive command, that is, a predetermined pulse signal to the target electronic expansion valve 20.

  FIG. 6 is a flowchart for explaining the processing contents of the electronic expansion valve drive processing executed by the control means shown in FIG. 5 according to a predetermined time schedule. The operation of the refrigerant circuit device will also be described by explaining the processing contents.

  In the electronic expansion valve drive process shown in FIG. 6, the control means 50 determines whether or not the compressor 11 is driven by the compressor drive control unit 51 (step S100). When the compressor 11 is stopped (Step S100: No), the control unit 50 returns the procedure and ends the current process without executing the process described later.

  On the other hand, when the compressor 11 is driven (step S100: Yes), the electronic expansion valve drive control unit 52 of the control means 50 inputs each evaporation temperature from the refrigerant temperature sensors S1 to S3 through the input processing unit 521. Then (step S110: Yes), the process proceeds to the next process. That is, the electronic expansion valve drive control unit 52 of the control means 50 determines whether to drive or stop driving each electronic expansion valve 20 through the valve opening / closing ratio determining unit 522, and when driving, the duty ratio (valve opening / closing ratio). Is determined (step S120).

  In the process of determining the valve opening / closing ratio, when it is necessary to lower the evaporation temperature of the refrigerant, the duty ratio is reduced, and the valve opening / closing ratio of the electronic expansion valve 20 determined in this process is the first electronic It is assumed that the expansion valve 20 is 20%, the second electronic expansion valve 20 is 40%, and the third electronic expansion valve 20 is 60%.

  The electronic expansion valve drive control unit 52 of the control means 50 that has determined the duty ratio performs the first priority electronic expansion valve setting process through the first priority expansion valve setting unit 523 (step S130).

  FIG. 7 is a flowchart showing the processing contents of the first priority expansion valve setting process in the electronic expansion valve drive process shown in FIG.

  In the first priority electronic expansion valve setting process, the electronic expansion valve drive control unit 52 reads information on the electronic expansion valve 20 set as the first priority expansion valve at the time of the previous valve opening / closing ratio determination from the memory 60 (step S131). ).

  If the electronic expansion valve 20 set as the first priority expansion valve does not have the smallest duty ratio (step S131: No), the electronic expansion valve drive control unit 52 passes through the first priority expansion valve setting unit 523. The first electronic expansion valve 20 having the smallest duty ratio is set as the first priority expansion valve (step S132), and then the procedure is returned to end the current process.

  On the other hand, when the electronic expansion valve 20 set as the first priority expansion valve has the smallest duty ratio (step S131: Yes), the electronic expansion valve drive control unit 52 passes through the first priority expansion valve setting unit 523. The second electronic expansion valve 20 having the second smallest duty ratio is set as the first priority expansion valve (step S133), and then the procedure is returned to end the current process.

  When the first priority expansion valve is set in step S130, the electronic expansion valve drive control unit 52 of the control means 50 calculates the operation cycle of each electronic expansion valve 20 through the operation cycle calculation unit 524 (step S140). .

  Here, a specific example of calculation of the operation cycle of each electronic expansion valve 20 will be described. When the first electronic expansion valve 20 having the smallest duty ratio is set as the first priority expansion valve in step S130, the following is performed.

  First, since the duty ratio of the first electronic expansion valve 20 as the first priority expansion valve is 20%, the off time (valve closing time) is a predetermined valve closing limit time (stored in the memory 60). For example, the ON time (valve opening time) is 20 (seconds) ÷ (100% −20%) − 20 = 5 seconds. That is, the first priority expansion valve has an on time of 5 seconds and an off time of 20 seconds.

  Next, for the second electronic expansion valve 20 and the third electronic expansion valve 20 other than the first priority expansion valve (first electronic expansion valve 20), the operation cycle upper limit time (for example, 60 seconds) stored in the memory 60 Is calculated as follows. The second electronic expansion valve 20 has an on time of 60 (seconds) × 40% = 24 seconds, and an off time of 60 (seconds) −24 (seconds) = 36 seconds. The third electronic expansion valve 20 has an on time of 60 (seconds) × 60% = 36 seconds, and an off time of 60 (seconds) −36 (seconds) = 24 seconds.

  By the way, when the second electronic expansion valve 20 having the second smallest duty ratio is set as the first priority expansion valve in step S130, the following is performed.

  First, since the duty ratio of the second electronic expansion valve 20 which is the first priority expansion valve is 40%, the off time (valve closing time) is a predetermined valve closing limit time (stored in the memory 60). For example, the ON time (valve opening time) is 20 (seconds) ÷ (100% −40%) − 20 = 13.3 seconds. That is, the first priority expansion valve has an on time of 13.3 seconds and an off time of 20 seconds.

  Next, for the first electronic expansion valve 20 and the third electronic expansion valve 20 other than the first priority expansion valve (second electronic expansion valve 20), the next operation cycle upper limit time stored in the memory 60 is used. Is calculated as follows. The first electronic expansion valve 20 has an on time of 60 (seconds) × 20% = 12 seconds, and an off time of 60 (seconds) −12 (seconds) = 48 seconds. The third electronic expansion valve 20 has an on time of 60 (seconds) × 60% = 36 seconds, and an off time of 60 (seconds) −36 (seconds) = 24 seconds.

  Thus, the electronic expansion valve drive control unit 52 that has calculated the operation cycle in step S140 outputs a drive command (pulse signal) corresponding to each operation cycle to each electronic expansion valve 20 through the output processing unit 525 ( Step S150), after which the procedure is returned to end the current process.

  According to this, about the 1st priority expansion valve, it is made to drive with the operation cycle according to the duty ratio in the mode that the off time becomes the valve closing limit time or less, and for the electronic expansion valve 20 other than the first priority expansion valve, It can be driven with an operation cycle corresponding to the duty ratio within the range of the operation cycle upper limit time.

  As described above, according to the refrigerant circuit device according to the present embodiment, the control unit 50 operates the operating cycle in accordance with the duty ratio in such a manner that the off time of the first priority expansion valve is equal to or less than the valve closing limit time. The electronic expansion valves 20 other than the first priority expansion valve are driven at the operation cycle corresponding to the duty ratio within the range of the operation cycle upper limit time, so that all the electronic expansion valves 20 are fully closed. The time can be less than the valve closing limit time. As a result, the drive timing of each electronic expansion valve 20 can be controlled so that the time for which all the electronic expansion valves 20 are fully closed does not exceed a certain time. As a result, the compressor 11 is damaged or the power consumption is reduced. Can be suppressed. In particular, for the first priority expansion valve, the service life of the electronic expansion valve 20 is extended by controlling the valve opening / closing cycle period to be extended without changing the duty ratio within the valve closing limit time. Can do.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to this, and various modifications can be made.

  In the above-described embodiment, the electronic expansion valve 20 having the smallest duty ratio is set as the first priority expansion valve. However, in the present invention, the electronic expansion valve having the smallest cumulative valve opening / closing frequency is the first priority expansion valve. May be set.

  As described above, the refrigerant circuit device according to the present invention is useful for, for example, a vending machine that sells canned beverages, plastic bottled beverages, and the like.

DESCRIPTION OF SYMBOLS 10 Refrigerant circuit 11 Compressor 12 Condenser 13 Evaporator 14 Refrigerant piping 20 Electronic expansion valve 20a Valve body 20b Inside valve body 30 Armature 31 Adsorption part 32 Side part 33 Valve body 2221 Small diameter flow path 50 Control means 51 Compressor drive control part 52 Electronic expansion valve drive control unit 521 Input processing unit 522 Valve opening / closing ratio determination unit 523 First priority expansion valve setting unit 524 Operation cycle calculation unit 525 Output processing unit 60 Memory S1 to S3 Refrigerant temperature sensor S4 to S6 Internal temperature sensor

Claims (4)

An evaporator disposed in each chamber and evaporating the refrigerant passing through the chamber;
A compressor that sucks and compresses the refrigerant evaporated in the evaporator;
A condenser for condensing the refrigerant compressed by the compressor;
A small-diameter channel that is disposed upstream of each of the evaporators and adiabatically expands the refrigerant condensed in the condenser, and reciprocates to open and close the inlet of the small-diameter channel. In a refrigerant circuit device comprising a refrigerant circuit in which a refrigerant pipe is sequentially connected to an electronic expansion valve having a valve body that allows or regulates passage of refrigerant through a small-diameter channel,
The ratio of the valve opening time to the operation cycle of each electronic expansion valve is determined as the valve opening / closing ratio from the evaporation temperature of the evaporator of the chamber that needs to be cooled according to a predetermined time schedule, and arbitrarily selected from the electronic expansion valves to be driven For the first priority expansion valve, the valve closing time is set in advance, and when all the electronic expansion valves are in the fully closed state, the valve closing limit time determined as the allowable drive time of the compressor is not exceeded. Control means for driving with the operation cycle according to the valve opening / closing ratio, and for the other electronic expansion valves with a driving cycle according to the valve opening / closing ratio within a predetermined operation cycle upper limit time range is provided. A refrigerant circuit device.   The refrigerant circuit device according to claim 1, wherein the control means sets the electronic expansion valve having the smallest valve opening / closing ratio as a first priority expansion valve.   2. The refrigerant circuit device according to claim 1, wherein the control unit sets the electronic expansion valve having the smallest cumulative valve opening / closing frequency as the first priority expansion valve.   When the electronic expansion valve having the smallest valve opening / closing ratio is set as the first priority expansion valve at the previous valve opening / closing ratio determination, the control means has the second smallest valve opening / closing ratio at the next valve opening / closing determination. The refrigerant circuit device according to any one of claims 1 to 3, wherein the electronic expansion valve is set as a first priority expansion valve.

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