JP2005331183A - Freezer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a freezer which automatically eliminates the clogging of an expansion mechanism. <P>SOLUTION: A bypass pipe 18 for a hot gas is branched from the side of a discharge opening of a compressor 11, connected in the vicinity of an exit of an expansion valve 13, and provided with a solenoid valve 19 in the midway. A temperature sensor 21 which detects an evaporation temperature of a refrigerant is provided in the vicinity of an entrance of an evaporator 14, and is connected to the side of an input of a control device 20 which controls opening/closing of the solenoid valve 19. The evaporation temperature of the refrigerant is detected during cooling operation, and, when the detected temperature is not higher than a predetermined temperature, it is determined that the expansion valve 13 is clogging up, and then the solenoid valve 19 is opened for a predetermined time. Thus, the hot gas discharged from the compressor 11 passes through the bypass pipe 18 to the side of the exit of the expansion valve 13 so that the expansion valve 13 is heated. As a result of this, the contamination accumulated in the expansion valve 13, especially, deposited and appearing in a lower temperature part is redissolved in the refrigerant or the like to remove such clogging. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigeration apparatus having a foreign matter removing function in a refrigeration circuit.

In general, a refrigeration apparatus provided in a cooling storage has a refrigeration circuit in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe to form a refrigerant circulation path. -The cooling action is exhibited as the low-pressure refrigerant evaporates.
By the way, there are cases where contamination (residual impurities, hereinafter simply referred to as contamination) is mixed in the refrigerant of this type of refrigeration circuit. Examples of the contamination include metal powder, oils other than refrigerating machine oil, and oil additives. Of these, oil and its additives do not appear as contaminants at room temperature, but may precipitate at low temperature parts and become contaminants, and these are not particularly removed without being removed by a mesh provided in a dryer or the like. However, it is easy to accumulate with an expansion valve having a complicated and narrow flow path, which may cause clogging. If it does so, there existed a problem that refrigerating capacity fell or it led to failure of other refrigerators.
Note that this type of refrigeration circuit and the problem of clogging due to contamination are described in Patent Document 1, for example.
JP-A-11-108504

  On the other hand, as one form of controlling the cooling temperature in the refrigerator, an electromagnetic valve is provided in the refrigeration circuit, and the cooling temperature is kept constant by controlling the supply and stop of the refrigerant to the evaporator by opening and closing the electromagnetic valve. Things are known. In this case, when small metal powder or the like that could not be removed by the mesh flows along with the refrigerant, for example, when the electromagnetic valve is closed, it may be caught between the valve body and the valve seat and may not be completely closed. If it does so, the supply of a refrigerant | coolant cannot be stopped and the problem that cooling will continue even if it exceeds preset temperature arises.

In commercial refrigerators, a hot gas bypass pipe with an electromagnetic valve is provided between the compressor outlet and the evaporator inlet, and this solenoid valve is opened to supply hot gas to the evaporator. The thing which performed defrosting by is known. In such a case, if the metal powder or the like bites into the electromagnetic valve and cannot be completely closed, the refrigerant leaks when returning to the normal cooling operation. There was a problem of becoming.
The present invention has been completed based on the above circumstances, and its object is to quickly eliminate clogging caused by foreign matter in the refrigeration circuit.

  According to a first aspect of the present invention, in the refrigeration apparatus including a refrigeration circuit in which a compressor, a condenser, an expansion mechanism, and an evaporator are sequentially connected by a refrigerant pipe to form a refrigerant circulation path, the expansion mechanism is heated. Therefore, hot gas introduction means for introducing the hot gas discharged from the compressor into the vicinity of the expansion mechanism, and clogging determination means for determining whether or not the expansion mechanism is clogged from the state of the refrigerant flowing through the refrigeration circuit; The present invention is characterized in that it comprises a control means for driving the hot gas introducing means when it is judged that the clogging means is clogged.

According to a second aspect of the present invention, in the first aspect of the present invention, the hot gas introducing means is connected between the outlet side of the compressor and the outlet side of the expansion mechanism by a hot gas bypass pipe. It is characterized in that the bypass pipe is provided with an opening / closing valve that is controlled to be opened and closed by the control means.
A third aspect of the invention is characterized in that, in the second aspect of the invention, a pressure reducing means is interposed in the bypass pipe.

According to a fourth aspect of the present invention, in the first aspect, the hot gas introduction unit is configured such that a hot gas bypass pipe is connected between an outlet side of the compressor and an inlet side of the condenser. A heat exchanging portion is formed between the middle of the bypass pipe and the outlet side of the expansion mechanism, and a switching valve that is controlled by the control means is provided at a branch portion of the bypass pipe. It has a characteristic where it exists.
According to a fifth aspect of the present invention, in the method according to any one of the first to fourth aspects, the clogging determining unit detects an evaporating temperature or an evaporating pressure of the refrigerant, and the detected value becomes a predetermined value or less. It is characterized in that a determination signal is output that there is a blockage in some cases.

  The invention of claim 6 includes a refrigeration circuit in which a compressor, a condenser, an expansion mechanism, and an evaporator are sequentially connected by a refrigerant pipe to form a refrigerant circulation path, and an on-off valve provided in the refrigeration circuit. In the refrigeration apparatus that controls the supply and stop of the refrigerant to the evaporator by opening and closing to maintain the cooling temperature constant, a cooling state detection means that detects the cooling state by the refrigeration circuit, and When the detection state by the cooling state detection means does not satisfy a predetermined condition, the clogging determination means for determining that the foreign matter is clogged in the on-off valve and outputting a determination signal, and when receiving this determination signal The present invention is characterized by comprising a valve drive control means for repeatedly opening and closing the on-off valve.

  The invention of claim 7 includes a refrigeration circuit in which a compressor, a condenser, an expansion mechanism, and an evaporator are sequentially connected by a refrigerant pipe to form a refrigerant circulation path, and the outlet of the compressor and the evaporator In the refrigerating apparatus provided with a hot gas bypass pipe provided with an on-off valve between the inlet and the degassing by opening the on-off valve and supplying hot gas to the evaporator, A cooling state detection means for detecting a cooling state by the refrigeration circuit, and a determination signal for determining that the on-off valve is clogged with foreign matter when the detection state by the cooling state detection means does not satisfy a predetermined condition And a valve drive control means for repeatedly opening and closing the open / close valve when receiving this determination signal.

<Invention of Claim 1>
When the expansion mechanism is clogged with foreign matter, the flow rate of the refrigerant decreases.For example, the state of the refrigerant such as the evaporation temperature and the evaporation pressure of the refrigerant changes from the normal time. It is determined that a foreign object is clogged with respect to the expansion mechanism. Based on this determination, the hot gas introduction means is driven, and hot gas is introduced into the vicinity of the expansion mechanism, whereby the expansion mechanism is heated and foreign matter is melted, and the expansion mechanism is clogged.
In particular, when clogging occurs in the expansion mechanism due to the type of contamination that precipitates at a low temperature part such as oil and its additives, the clogging can be automatically eliminated. Therefore, a predetermined freezing capacity can be ensured.

<Invention of Claim 2>
When it is determined that there is clogging, the on-off valve is opened, whereby hot gas flows through the bypass pipe to the outlet side of the expansion mechanism, and the expansion mechanism is heated.
<Invention of Claim 3>
When hot gas is introduced to the outlet side of the expansion mechanism, the pressure on the low-pressure side in the refrigeration circuit increases rapidly. Here, if the expansion mechanism is an internal pressure equalization type temperature type expansion valve, the pressure on the low-pressure side near the outlet of the expansion valve is balanced, so that the expansion valve may malfunction.
In this respect, in the present invention, since the hot gas is decompressed and introduced to the outlet side of the expansion valve, a rapid pressure increase on the low pressure side is suppressed, and malfunction of the expansion valve can be prevented.

<Invention of Claim 4>
When it is determined that clogging has occurred, the switching valve is switched so that hot gas flows through the bypass pipe and heat exchange is performed between the expansion mechanism and the outlet side of the expansion mechanism. Is heated.
<Invention of Claim 5>
If the expansion mechanism is clogged with foreign matter, the flow rate of the refrigerant decreases, so the evaporation temperature or evaporation pressure of the refrigerant in the evaporator decreases. Therefore, the evaporation temperature or evaporation pressure of the refrigerant is detected, and when the detected value is equal to or lower than a predetermined value, it is considered that the expansion mechanism is clogged and a determination signal is output.

<Invention of Claim 6>
If the on-off valve is clogged with foreign matter, it cannot be completely closed, so the supply of refrigerant cannot be stopped. For example, cooling continues even when the set temperature in the cabinet is exceeded, causing an abnormal cooling condition. . Therefore, when the cooling state such as the cooling temperature in the warehouse is detected by the cooling state detection means and the detection value does not satisfy a predetermined condition such as being less than a predetermined value, the clogging determination means It is determined that there is a clogged foreign object and a determination signal is output. When the determination signal is issued, the on / off valve is repeatedly opened / closed by the valve drive control means, whereby the foreign matter is peeled off and the clogging of the on / off valve is eliminated.
In particular, when the on / off valve is clogged by biting contamination such as metal powder, the clogging can be automatically eliminated. It is possible to reliably stop the supply of the refrigerant and to prevent the occurrence of an excessively cold state.

<Invention of Claim 7>
If the on-off valve is clogged with foreign matter, it will not be completely closed, so even when returning from the defrosting operation to the cooling operation, the refrigerant leaks into the bypass pipe, affecting the refrigerant used for cooling. The cooling state changes, for example, the cooling rate of the battery becomes slow. Therefore, when the cooling state such as the cooling rate by the refrigeration circuit is detected by the cooling state detection means, and the detection state does not satisfy the predetermined condition, the clogging determination means causes the foreign matter to be clogged with respect to the on-off valve. It is determined that there is an error, and a determination signal is issued. When the determination signal is issued, the on / off valve is repeatedly opened / closed by the valve drive control means, whereby the foreign matter is peeled off and the clogging of the on / off valve is eliminated.
Similarly, when the on / off valve is clogged by biting contamination such as metal powder, the clogging can be automatically eliminated. During the cooling operation, the refrigerant can be prevented from leaking to the bypass pipe, and thus a predetermined refrigeration capacity can be exhibited.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to FIGS. The refrigeration apparatus of this embodiment is equipped in a cooling storage, and the refrigeration circuit 10 includes a compressor 11, a condenser 12, an expansion valve 13, and an evaporator 14 as shown in FIG. It is configured by circulating connection with. As shown in FIG. 2, the expansion valve 13 is a temperature type expansion valve whose opening is adjusted based on the temperature on the outlet 14Y side of the evaporator 14 detected by the temperature sensing cylinder 13A, and is an external pressure equalizing type. is there.

In the operation of the refrigeration circuit 10, a high-temperature / high-pressure refrigerant gas is obtained by the compressor 11, which is condensed by the condenser 12 to be a high-temperature / high-pressure refrigerant liquid and sent to the expansion valve 13. In the expansion valve 13, the high-temperature / high-pressure refrigerant liquid expands into a low-temperature / low-pressure refrigerant liquid, which evaporates in the evaporator 14 and performs a predetermined cooling action by the endothermic action at that time. The refrigerant gas is returned to the compressor 11 side.
In this refrigeration circuit 10, a line 16A connecting the discharge port 11Y of the compressor 11 and the inlet 12X of the condenser 12, and a line 16B connecting the outlet 13Y of the expansion valve 13 and the inlet 14X of the evaporator 14 A hot gas bypass pipe 18 is connected between them. In particular, as shown in FIG. 2, the outflow side of the bypass pipe 18 is desirably arranged at a location as close as possible to the expansion valve 13 in the pipe line 16B. An electromagnetic valve 19 for opening and closing the bypass pipe 18 is provided in the middle of the bypass pipe 18.

In this embodiment, in view of the fact that when the expansion valve 13 is clogged as described later, the flow rate of the refrigerant flowing through the expansion valve 13 is reduced, the evaporation temperature of the refrigerant in the evaporator 14 decreases. It is assumed that the expansion valve 13 is clogged when the evaporation temperature becomes equal to or lower than the predetermined temperature α. The predetermined temperature α is set in consideration of the normal evaporation temperature for each model.
For this reason, a temperature sensor 21 for detecting the evaporation temperature of the refrigerant is attached to, for example, the inlet 14 </ b> X of the evaporator 14. The temperature sensor 21 is connected to the input side of the control device 20, and the electromagnetic valve 19 of the bypass pipe 18 is connected to the output side of the control device 20. The control device 20 is equipped with a microcomputer, a timer, and the like, and controls the opening and closing of the electromagnetic valve 19 based on a predetermined program.

The operation of this embodiment is as follows. When the compressor 11 is operated in the refrigeration circuit 10, the refrigerant circulates and flows through the refrigerant pipe 15 while repeating the state change as described above, and performs a predetermined cooling action at the evaporator 14 portion. Here, there are cases where various types of contamination (hereinafter simply referred to as “contamination”) are mixed in the refrigerant. Of these, if there is an oil other than the refrigerating machine oil or its additive, these are the low temperature parts of the refrigeration circuit 10. In this case, it is likely to deposit on the expansion valve 13 having a complicated structure and a narrow flow path, which may cause clogging.
When the expansion valve 13 is clogged in this way, the amount of refrigerant flowing to the evaporator 14 is reduced, resulting in a phenomenon that the evaporation temperature of the refrigerant in the evaporator 14 is lowered.

  Therefore, when the temperature evaporating temperature of the refrigerant is detected by the temperature sensor 21 provided at the inlet 14X of the evaporator 14, and the detected temperature becomes equal to or lower than a predetermined temperature α as shown in the flowchart of FIG. In step S2, the electromagnetic valve 19 interposed in the bypass pipe 18 is opened for a predetermined time. Thereby, the hot gas discharged from the compressor 11 flows through the bypass pipe 18 to the outlet 13Y side of the expansion valve 13, and the expansion valve 13 is heated. As a result, the contamination accumulated in the expansion valve 13 is redissolved in the refrigerant and the like, and the clogging is removed.

When the predetermined time has elapsed, the electromagnetic valve 19 is closed (step S3), and the supply of hot gas to the expansion valve 13 is stopped. After that, when a predetermined standby time has elapsed (“Yes” in step S4), it is determined again in step S1 whether or not the evaporation temperature of the refrigerant has recovered, and if the evaporation temperature has recovered (step S1 is “ No "), the cooling operation is continued. On the other hand, if the evaporation temperature is still low (step S1 is “Yes”), it is considered that the expansion valve 13 is still clogged, and the heating operation of the expansion valve 13 with hot gas is performed (step S2 to step S4). .
If the operation of opening the solenoid valve 19 of the bypass pipe 18 is performed a plurality of times, for example, three times within a predetermined time, if the recovery of the evaporation temperature is not observed, the clogging of the expansion valve 13 can be heated and dissolved. It may be due to something other than contamination, or there may be another failure location, so that an error may be displayed.

As described above, in the present embodiment, when the expansion valve 13 is clogged due to a type of contamination that precipitates at a low temperature part such as oil and its additives, the expansion valve 13 is heated by using hot gas. The clogging can be resolved automatically. Therefore, a predetermined freezing capacity can be ensured.
In particular, since the hot gas is supplied to the expansion valve 13 only when it is considered that clogging has occurred, interruption of the cooling operation can be minimized.

<Embodiment 2>
FIG. 4 shows Embodiment 2 of the present invention. In the second embodiment, an improvement is made so as to be suitable when the expansion valve 25 is an internal pressure equalizing type.
In the refrigeration circuit 10A of the second embodiment, a capillary tube 26 is provided downstream of the solenoid valve 19 in the hot gas bypass pipe 18. In short, the bypass pipe 18 on the upstream side of the electromagnetic valve 19 has substantially the same pipe diameter as that of the refrigerant pipe 15, whereas the capillary tube 26 has a smaller pipe diameter. Other structures and control procedures are the same as those in the first embodiment.

The internal pressure equalization type temperature expansion valve 25 has a structure that balances the pressure on the inlet 14X side of the evaporator 14, that is, on the low pressure side near the outlet 25Y of the expansion valve 25. Therefore, when hot gas rapidly flows through the bypass pipe 18 and is introduced to the outlet 25Y side of the expansion valve 25 in order to heat the expansion valve 25, the pressure on the low pressure side in the refrigeration circuit 10A rapidly increases, so that the expansion The valve 25 may malfunction.
In this regard, in the second embodiment, the flow rate of the hot gas is limited by the capillary tube 26, that is, the pressure is reduced and introduced to the outlet 25Y side of the expansion valve 25, so that a rapid pressure increase on the low pressure side is suppressed, and the expansion valve It is possible to prevent 25 from malfunctioning.

<Embodiment 3>
5 and 6 show Embodiment 3 of the present invention. In the refrigeration circuit 10B according to the third embodiment, in the refrigeration circuit shown in the first embodiment, between the discharge port 11Y of the compressor 11 and the inlet 12X of the condenser 12, separately from the pipe line 16A constituting the circulation path. A hot gas bypass pipe 30 is provided. As shown in FIG. 6, a predetermined length portion at a midway position of the bypass pipe 30 is in close contact with the pipe line 16 </ b> B connected to the outlet 13 </ b> Y of the expansion valve 13, thereby forming a heat exchange section 31. On the other hand, a three-way valve 33 is provided at a branch portion of the bypass pipe 30.
Further, the refrigerant evaporating temperature is detected by the temperature sensor 21 provided at the inlet 14X of the evaporator 14, and when the detected temperature becomes equal to or lower than the predetermined temperature α, it is assumed that the expansion valve 13 is clogged. This is the same as in the first embodiment, and when it is determined that clogging has occurred, the three-way valve 33 is switched to the bypass pipe 30 side by a signal from the control device 20A.

The operation of the third embodiment is as follows. When the temperature sensor 21 detects that the evaporation temperature of the refrigerant has become equal to or lower than the predetermined temperature α, the three-way valve 33 is switched to the bypass pipe 30 side, and hot gas discharged from the compressor 11 passes through the bypass pipe 30. The pipe 16B is heated in the heat exchanging section 31, and the expansion valve 13 is heated. As a result, the contamination accumulated in the expansion valve 13 is redissolved in the refrigerant and the like, and the clogging is removed. When the predetermined time has elapsed, the three-way valve 33 is switched to the pipe line 16A side, and the supply of hot gas to the heat exchange unit 31 is stopped. Subsequently, a cooling operation is performed.
If clogging cannot be resolved at a time, hot gas is again supplied to the heat exchanging unit 31 to perform the heating operation of the expansion valve 13, and the heating operation is performed a predetermined number of times (for example, three times) within a predetermined time. If recovery of the evaporating temperature is not observed even if is performed, an error display can be applied as in the first embodiment.
In the third embodiment, the same effect as in the first embodiment can be obtained.

<Related technologies>
FIG. 7 shows the related art. As a means for heating the expansion valve 13, a heater 35 is provided in the vicinity of the outlet 13 </ b> Y of the expansion valve 13. That is, when it is determined that the expansion valve 13 is clogged, the heater 35 is energized for a predetermined time, whereby the expansion valve 13 is heated, and contamination accumulated in the expansion valve 13 is re-dissolved in the refrigerant, etc. Clogging is removed.

<Embodiment 4>
A fourth embodiment of the present invention will be described with reference to FIGS. In the fourth embodiment, in a refrigerator-freezer of a type that controls the internal temperature by turning on and off the electromagnetic valve provided in the refrigeration circuit, when the electromagnetic valve is clogged, this is automatically resolved. doing.
In the refrigeration circuit 40 in this embodiment, as shown in FIG. 8, a condenser 42 with a condenser fan 42 </ b> A is connected to the outlet side of the compressor 41, and a dryer 43 is sequentially connected to the downstream side thereof. On the downstream side of the dryer 43, there are solenoid valves 45A and 45B functioning as line valves, capillary tubes 46A and 46B, and evaporators 47A and 47B connected in series to the refrigeration side and refrigeration side refrigerant circulation pipes 48A and 48B. Provided in parallel and connected to the inlet side of the compressor 41 by reflux. The refrigerators 47A and 47B on the refrigeration side and the refrigeration side are arranged in the refrigerator compartment and the freezer compartment, respectively, and internal fans 49A and 49B are attached to the evaporators 47A and 47B, respectively. The capillary tubes 46A and 46B are configured to exchange heat with the refrigerant piping on the outlet side of the evaporators 47A and 47B.

  As shown schematically in FIG. 9, the structure of the electromagnetic valves 45 </ b> A and 45 </ b> B is always closed by pressing the valve body 52 provided at the tip of the movable iron core 51 against the valve seat 53 by the spring force of the biasing spring 50. When the coil 54 is energized and excited, the movable iron core 51 is attracted toward the fixed iron core 55 against the spring force of the biasing spring 50, and the valve body 52 is separated from the valve seat 53 to open the valve. It has come to be.

The following control is performed during the cooling operation. In the refrigerator compartment and the freezer compartment, temperature sensors 61A and 61B (see FIG. 10) for detecting the inside temperature are provided. When the internal temperature is detected in each of the refrigerator compartment and the freezer compartment and the internal temperature is higher than a preset temperature, the corresponding electromagnetic valves 45A and 45B are opened and the internal fans 49A and 49B are driven. Is done. When either one of the electromagnetic valves 45A and 45B is opened, the compressor 41 is driven.
When the refrigeration side electromagnetic valve 45A is opened, a circulation path is formed through the refrigeration side refrigerant circulation pipe 48A, and the liquid refrigerant discharged from the condenser 42 flows from the electromagnetic valve 45A to the capillary tube 46A and expands. The liquid refrigerant evaporates in the evaporator 47A. Along with this, the generated cool air is circulated in the refrigerator compartment to be cooled.
Similarly, when the refrigeration-side electromagnetic valve 45B is opened, a circulation path passing through the refrigeration-side refrigerant circulation pipe 48B is formed, and the liquid refrigerant flows from the electromagnetic valve 45B to the capillary tube 46B. It cools by evaporating with the evaporator 47B, and the cool air produced | generated in connection with it circulating in a freezer compartment.

In the refrigerator compartment and the freezer compartment, when the internal temperature becomes lower than the set temperature, the solenoid valves 45A and 45B are closed to stop the supply of refrigerant and the internal fans 49A and 49B are stopped to stop the cooling operation. The When both solenoid valves 45A and 45B are closed, the operation of the compressor 41 is also stopped.
In short, in the refrigerator compartment and the freezer compartment, the corresponding electromagnetic valves 45A and 45B are controlled to open and close depending on whether the internal temperature is higher or lower than the set temperature, and supply and stop of the refrigerant to each evaporator 47A and 47B. Are controlled so that each is cooled to approximately the set temperature.

In this type of refrigeration circuit 40, when small metal powder that cannot be removed by a mesh attached to the dryer 43 or the like out of the contamination mixed in the refrigerant circulates together with the refrigerant, when the solenoid valves 45A and 45B are closed, Metal powder may be caught between the valve body 52 and the valve seat 53, and the electromagnetic valves 45A and 45B may not be completely closed.
In this embodiment, as described above, when the electromagnetic valves 45A and 45B are clogged, that is, when metal powder is caught, the purpose is to eliminate this automatically. It is assumed that 45B has been bitten. That is, if the metal powder does not completely close into the electromagnetic valves 45A and 45B, the supply of the refrigerant cannot be stopped, and therefore the cooling is continued even if the set temperature is exceeded.
Therefore, the internal temperature of the refrigerator compartment and the freezer compartment is detected, and when the detected values are lower than the predetermined values β1 and β2, it is assumed that the electromagnetic valves 45A and 45B are caught. The predetermined values β1 and β2 are values obtained by subtracting a constant value from the set temperatures of the refrigerator compartment and the freezer compartment, respectively.

  When it is determined that the electromagnetic valves 45A and 45B are bitten as described above, the foreign matter removing operation is performed on the electromagnetic valves 45A and 45B, and the control device 60 (FIG. 10) for that purpose is provided. The control device 60 is equipped with a microcomputer, a timer, and the like, and a predetermined program to be described later is executed in detail. On the input side of the control device 60, the temperature sensors 61A and 61B respectively provided in the refrigeration room and the freezing room described above are connected. On the output side, the valve driving means 62 is used to perform the foreign substance removal operation. Electromagnetic valves 45A and 45B are connected via The foreign matter removing operation is an operation for opening and closing the electromagnetic valves 45A and 45B, for example, B times continuously in A seconds. An error display unit 63 is also connected to the output side of the control device 60.

The operation of this embodiment will be described with reference to the flowchart of FIG.
During the cooling operation, for example, when metal powder is caught in the refrigeration side electromagnetic valve 45A, the internal temperature of the refrigeration chamber becomes lower than the set temperature ("Yes" in step S12), and in step S13, the refrigeration side electromagnetic valve Even though 45A is in the closed state, the refrigerant leaks and is supplied, so that the internal temperature of the refrigerator compartment further decreases. If the detected temperature falls below the predetermined temperature β1 (“Yes” in step S14), it is determined that the electromagnetic valve 45A has been bitten and the foreign matter removal operation is not performed within 30 minutes (step S15). Is “Yes”), the foreign matter removing operation is performed for a predetermined time in step S16. That is, when the electromagnetic valve 45A is repeatedly opened and closed in a short time, the metal powder adhering to the valve body 52 and the valve seat 53 is removed, and the engagement of the electromagnetic valve 45A is eliminated.

  When the foreign matter removal operation is completed, the normal cooling operation is resumed. At that time, even if 30 minutes have passed after the foreign matter removal operation is completed, if the detected temperature in the refrigerator compartment is still lower than the predetermined temperature β1, it is considered that the electromagnetic valve 45A is still biting, and the foreign matter is again detected. A removal operation is performed. However, when the foreign matter removal operation is executed three times in succession (step S17 is “Yes”), it is considered that the metal powder cannot be removed well, or there is another failure part. That is displayed by the error display unit 63.

Similarly, when the metal powder is caught in the freezing-side electromagnetic valve 45B, the freezer compartment temperature is lower than the set temperature ("Yes" in step S19), and in step S20, the freezing-room electromagnetic valve is set. Even though 45B is in the closed state, the refrigerant leaks and is supplied, so that the temperature inside the freezer compartment further decreases. If the detected temperature falls below the predetermined temperature β2 (“Yes” in step S21), it is determined that the electromagnetic valve 45B has been bitten, and the foreign matter removing operation is not performed within 30 minutes (step S22). Is “Yes”), the foreign matter removal operation is performed for a predetermined time in step S23. Similarly, when the electromagnetic valve 45B is repeatedly opened and closed in a short time, the metal powder adhering to the valve body 52 and the valve seat 53 is removed, and the engagement of the electromagnetic valve 45B is eliminated.
If the detected temperature in the freezer compartment is below the predetermined temperature β2 even after 30 minutes have passed since the completion of the foreign matter removal operation, the foreign matter removal operation is performed again, and the foreign matter removal operation is repeated three times. When executed, an error is displayed as in the refrigeration side.

  As described above, in the present embodiment, the foreign matter removing operation, that is, the repetitive opening / closing operation is performed on the electromagnetic valves 45A and 45B, particularly when the electromagnetic valves 45A and 45B are clogged by biting metal powder among the contamination. By removing the metal powder, the clogging can be automatically eliminated. As a result, the supply of the refrigerant to the evaporators 47A and 47B side is surely stopped, and as a result, it is possible to prevent the situation of being too cold.

<Embodiment 5>
A fifth embodiment of the present invention will be described with reference to FIGS. In the fifth embodiment, a hot gas bypass pipe having a solenoid valve interposed between the compressor outlet and the evaporator inlet is provided, and the solenoid valve is opened to supply hot gas to the evaporator. In the refrigerator-freezer in which defrosting is performed, when the electromagnetic valve is clogged, the case of automatically eliminating this is illustrated.

  In the present embodiment, refrigeration circuits 70A and 70B on the refrigeration side and the refrigeration side are individually provided. As shown in FIG. 12, compressors 71A and 71B, condensers 72A and 72B, dryers 73A and 73B, capillaries, respectively. The tubes 74A and 74B and the evaporators 75A and 75B are connected by circulation through refrigerant pipes 76A and 76B. However, both the condensers 72A and 72B are provided side by side, and the condenser fan 77 is also used. Each capillary tube 74A, 74B is configured to exchange heat with the refrigerant pipes 76A, 76B on the outlet side of the evaporators 75A, 75B. A high-pressure switch 78 that functions to stop the compressor 71B when the high-pressure side abnormally rises is connected to the high-pressure portion on the refrigeration side.

  On the other hand, for defrosting, hot gas bypass pipes 80A and 80B are provided between the outlets of the compressors 71A and 71B and the inlets of the evaporators 75A and 75B in the refrigeration circuits 70A and 70B on the refrigeration side and the freezing side. In the middle, electromagnetic valves 81A and 81B are interposed. The structure of the electromagnetic valves 81A and 81B is the same as that of the electromagnetic valves 45A and 45B shown in the fourth embodiment. Each of the evaporators 75A and 75B is equipped with defrost sensors 83A and 83B for detecting the temperature of the evaporators 75A and 75B and determining whether or not the defrosting is completed.

  The following control is performed during the cooling operation. When the compressors 71A and 71B are driven in the refrigeration circuits 70A and 70B, the low-temperature and low-pressure liquid refrigerant evaporates in the evaporators 75A and 75B to generate a cooling action, and the cold air is generated in the refrigerator compartment. Or it is circulated through the freezer and cooled. Temperature sensors 86A and 86B (see FIG. 13) for detecting the internal temperature are provided in the refrigerator compartment and the freezer compartment, respectively, and the internal temperature is detected in the refrigerator compartment and the freezer compartment, respectively. When the temperature becomes lower than a predetermined set temperature, the corresponding compressors 71A and 71B are stopped. When the temperature becomes higher than the set temperature, the compressors 71A and 71B are re-driven. Are substantially cooled to their respective set temperatures.

  On the other hand, when switching to the defrosting operation, the solenoid valves 81A and 81B provided in the bypass pipes 80A and 80B are opened, and hot gas is introduced into the evaporators 75A and 75B through the bypass pipes 80A and 80B. The devices 75A and 75B are heated, and the frost attached to the evaporators 75A and 75B is melted and removed, that is, defrosted. During this time, the temperature of the evaporators 75A and 75B is detected by the defrost sensors 83A and 83B, and when the detected temperature exceeds a predetermined value, it is considered that the defrosting is completed, and the corresponding electromagnetic valves 81A and 81B are closed and cooled. Driving is resumed.

Here, when contaminants such as small metal powders are mixed in the refrigerant and the defrosting operation is performed, the bypass pipes 80A and 80B are circulated together with the hot gas, and when the defrosting operation is completed and the solenoid valves 81A and 81B are closed. Metal powder may be caught between the valve body 52 and the valve seat 53, and the electromagnetic valves 81A and 81B may not be completely closed.
In this embodiment, as described above, when the electromagnetic valves 81A and 81B functioning as hot gas valves are clogged, that is, when metal powder is caught, the purpose is to automatically resolve this, The method assumes that the electromagnetic valves 81A and 81B are bitten by the method. If the metal powder is caught in the solenoid valves 81A and 81B and is not completely closed, the hot gas leaks to the evaporators 75A and 75B when returning to the cooling operation. That is, the predetermined refrigeration function is not exhibited, and the cooling rate in the cabinet is slowed down.
Therefore, for example, when the internal temperature is detected in the refrigerator compartment and the freezer compartment and it takes more than Z hours to lower the internal temperature from X ° C. to Y ° C. It is assumed that the electromagnetic valves 81A and 81B are bitten. For example, Y ° C. is a set temperature of the refrigerator compartment and the freezer compartment, and X ° C. is a value obtained by adding a constant temperature to each set temperature.

  When it is determined that the electromagnetic valves 81A and 81B are bitten as described above, the foreign matter removing operation is performed on the electromagnetic valves 81A and 81B, and a control device 85 is provided (FIG. 13). The control device 85 is equipped with a microcomputer, a timer, and the like, and a predetermined program to be described later is executed in detail. On the input side of the control device 85, temperature sensors 86A and 86B respectively provided in the refrigerating room and the freezing room described above are connected, while on the output side, valve driving means 87 for performing a foreign matter removing operation. The solenoid valves 81A and 81B are connected via The foreign matter removing operation is an operation of opening and closing the electromagnetic valves 81A and 81B, for example, B times continuously in A seconds. An error display unit 88 is also connected to the output side of the control device 85.

The operation of this embodiment will be described with reference to the flowchart of FIG.
When the cooling operation is performed on the refrigeration side, as shown in steps S31 to S36, when the refrigerator internal solenoid valve 81A is closed and the internal temperature of the refrigeration chamber exceeds the set value, the compressor 71A When it is driven and falls below the set value, the driving of the compressor 71A is repeatedly stopped, and the refrigerator compartment is maintained substantially at the set temperature.
Here, if the electromagnetic valve 81A is bitten, the hot gas leaks, so that a predetermined refrigeration capacity cannot be obtained, and so-called cooling is poor. Then, if it takes more than Z hours for the internal temperature of the refrigerator compartment to drop from X ° C. to Y ° C. (Step S37 “Yes”), it is determined that the electromagnetic valve 81A has been bitten, and the foreign matter removal operation is performed within the Z time. In step S39, the foreign matter removing operation is performed for a predetermined time under the condition that it is not performed (step S38 is “Yes”). That is, by repeatedly opening and closing the electromagnetic valve 81A in a short time, the metal powder adhering to the valve body 52 and the valve seat 53 is removed, and the biting in the electromagnetic valve 81A is eliminated.

When the foreign matter removal operation is completed, the normal cooling operation is resumed. At that time, even if the Z time has elapsed after the foreign matter removal operation is completed, if the internal temperature still takes more than Z time to decrease from X ° C to Y ° C, the electromagnetic valve 81A is still stuck. It is assumed that there is, and the foreign matter removal operation is executed again. However, if the foreign matter removal operation is executed three times in succession (step S40 is “Yes”), it is considered that the metal powder cannot be removed well, or there is another failure part. The fact is displayed by the error display unit 88.
In addition, the same control as the refrigerator compartment side is performed also in the freezer compartment side.

  As described above, in the present embodiment, when the electromagnetic valves 81A and 81B functioning as hot gas valves are clogged due to the biting of metal powder among the contaminants, foreign matter is generated with respect to the electromagnetic valves 81A and 81B. By performing the removal operation, that is, the repeated opening and closing operation, the metal powder can be removed and the clogging can be automatically eliminated. As a result, it is possible to prevent the refrigerant (hot gas) from leaking to the bypass pipes 80A and 80B during the cooling operation, and thus to exhibit a predetermined refrigeration capacity.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In Embodiments 1 to 3, the evaporating pressure of the refrigerant may be detected to determine whether or not the expansion valve is clogged. The detected value of the evaporating pressure may be calculated from the evaporating temperature, or may be directly detected by a pressure sensor.
(2) The location for detecting the evaporation temperature or the evaporation pressure of the refrigerant may be a location other than the inlet side, such as the outlet side of the evaporator.

(3) In the first or third embodiment, a type using another type of expansion mechanism such as a capillary tube instead of the temperature type expansion valve. Conversely, in the fourth or fifth embodiment, the temperature type expansion valve instead of the capillary tube. The present invention can be similarly applied to those using the above.
(4) The technology for eliminating clogging of the solenoid valve shown in Embodiment 4 or 5 is not limited to the refrigerator-freezer exemplified in the embodiment, and for example, temperature control is individually performed for a plurality of refrigerator compartments having substantially the same cooling temperature zone. It is also applicable to the type of
(5) Furthermore, the present invention is not limited to refrigerators and refrigerator-freezers, and can be widely applied to all refrigeration apparatuses mounted on other refrigeration equipment such as ice machines and beverage equipment.

1 is a circuit configuration diagram of a refrigeration circuit according to Embodiment 1 of the present invention. Schematic cross section near the expansion valve Flowchart of clogging elimination control according to the first embodiment The circuit block diagram of the refrigerating circuit of Embodiment 2. Circuit configuration diagram of refrigeration circuit of Embodiment 3 Schematic cross section near the expansion valve Circuit diagram of related technology refrigeration circuit The circuit block diagram of the freezing circuit which concerns on Embodiment 4 of this invention. Schematic sectional view of solenoid valve The block diagram which shows the control system of clogging elimination of Embodiment 4. Flow chart of the control The circuit block diagram of the freezing circuit which concerns on Embodiment 5 of this invention. The block diagram which shows the control system of clogging elimination of Embodiment 5. Flow chart of the control

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10, 10A, 10B ... Refrigeration circuit 11 ... Compressor 12 ... Condenser 13 ... Expansion valve (expansion mechanism) 14 ... Evaporator 15 ... Refrigerant piping 18 ... Bypass pipe 19 ... Solenoid valve (open / close valve) 20, 20A ... Control device DESCRIPTION OF SYMBOLS 21 ... Temperature sensor 25 ... Expansion valve (expansion mechanism) 26 ... Capillary tube (pressure reduction means) 30 ... Bypass pipe 31 ... Heat exchange part 33 ... Three-way valve (switching valve) 40 ... Refrigeration circuit 41 ... Compressor 42 ... Condenser 45A , 45B ... Solenoid valve (open / close valve) 46A, 46B ... Capillary tube (expansion mechanism) 47A, 47B ... Evaporator 60 ... Controller 61A, 61B ... (inside) temperature sensor 62 ... Valve drive means 70A, 70B ... Refrigeration circuit 71A, 71B ... Compressor 72A, 72B ... Condenser 74A, 74B ... Capillary tube (expansion mechanism) 75A, 75B ... Evaporation 76A, 76B ... refrigerant pipe 80A, 80B ... bypass pipe 81A, 81B ... solenoid valve (on-off valve) 85 ... control device 86A, 86B ... (inside the refrigerator) Temperature sensor 86 ... valve drive means

Claims (7)

In a refrigeration apparatus including a refrigeration circuit in which a compressor, a condenser, an expansion mechanism, and an evaporator are sequentially connected by a refrigerant pipe to form a refrigerant circulation path.
Hot gas introduction means for introducing hot gas discharged from the compressor into the vicinity of the expansion mechanism to heat the expansion mechanism;
Clogging determining means for determining the presence or absence of clogging of foreign matter with respect to the expansion mechanism from the state of the refrigerant flowing through the refrigeration circuit;
A refrigeration apparatus comprising: a control unit that drives the hot gas introduction unit when it is determined that the clogging unit is clogged. The hot gas introducing means is connected between the outlet side of the compressor and the outlet side of the expansion mechanism by a hot gas bypass pipe, and an open / close valve controlled to be opened and closed by the control means is provided in the bypass pipe. The refrigeration apparatus according to claim 1, comprising: The refrigeration apparatus according to claim 2, wherein a decompression means is interposed in the bypass pipe. The hot gas introducing means has a hot gas bypass pipe connected between the outlet side of the compressor and the inlet side of the condenser, and between the middle of the bypass pipe and the outlet side of the expansion mechanism. 2. The refrigeration apparatus according to claim 1, wherein a heat exchange section is formed and a switching valve that is controlled to be switched by the control means is provided at a branch portion of the bypass pipe. The clogging determining means detects an evaporating temperature or an evaporating pressure of a refrigerant, and outputs a determination signal that there is a clogging when the detected value becomes a predetermined value or less. The refrigeration apparatus according to any one of claims 1 to 4. A compressor, a condenser, an expansion mechanism, and an evaporator are sequentially connected by a refrigerant pipe to provide a refrigeration circuit in which a refrigerant circulation path is formed, and the evaporation is performed by opening and closing an on-off valve provided in the refrigeration circuit. In the refrigeration apparatus that maintains the cooling temperature constant by controlling the supply and stop of the refrigerant to the container,
Cooling state detection means for detecting a cooling state by the refrigeration circuit;
A clogging determining unit that determines that the on-off valve is clogged with foreign matter and outputs a determination signal when the detection state by the cooling state detection unit does not satisfy a predetermined condition;
A refrigeration apparatus comprising valve drive control means for repeatedly opening and closing the on-off valve when receiving this discrimination signal. A compressor, a condenser, an expansion mechanism, and an evaporator are sequentially connected by refrigerant piping to provide a refrigeration circuit in which a refrigerant circulation path is formed, and open and close between the outlet of the compressor and the inlet of the evaporator In a refrigeration apparatus provided with a hot gas bypass pipe provided with a valve, and performing defrosting by opening the on-off valve and supplying hot gas to the evaporator,
Cooling state detection means for detecting a cooling state by the refrigeration circuit;
A clogging determining unit that determines that the on-off valve is clogged with foreign matter and outputs a determination signal when the detection state by the cooling state detection unit does not satisfy a predetermined condition;
A refrigeration apparatus comprising valve drive control means for repeatedly opening and closing the on-off valve when receiving this discrimination signal.

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