JP6202054B2 - Liquid cooling device - Google Patents

Description

  The present invention relates to a liquid cooling apparatus having an evaporator for cooling a liquid, for example.

As a liquid cooling device, for example, a cooling fluid for a machine tool such as a grinding machine or a machining center, a spindle lubricating oil (hereinafter referred to as “working fluid”), and a compressor, a condenser, an expansion valve, and an evaporator are cooled. There is a submerged type liquid cooling apparatus that includes a refrigerant circuit connected to the tank and cools the working fluid by an evaporator immersed in the working fluid stored in a tank.

JP2012-93067

In conventional immersion type liquid cooling devices, the opening degree of the expansion valve is generally controlled based on the command of the liquid temperature in the tank and the compressor frequency, and the opening degree of the expansion valve is the liquid in the tank at that time. Based on the temperature, control is performed so that substantially all of the refrigerant evaporates in the evaporator. However, when stagnation of liquid occurs in the tank (when the temperature of the liquid in the tank becomes uneven), almost all of the refrigerant is not evaporated in the evaporator, and the liquid refrigerant is sucked into the compressor. There is a problem that the compressor breaks.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid cooling device that can prevent a compressor from being broken even when liquid stagnation occurs in a tank.

According to a first aspect of the present invention, there is provided a liquid cooling apparatus comprising: a refrigerant circuit connected to a compressor, a condenser, an expansion valve, and an evaporator; a tank that houses a liquid in which the evaporator is disposed; and a liquid in the tank Temperature detecting means for detecting the temperature of the compressor, control means for controlling the frequency of the compressor and the opening of the expansion valve based on the liquid temperature detected by the temperature detecting means, and the discharge pipe temperature of the compressor, Correction means for correcting the liquid temperature detected by the temperature detection means to a lower correction liquid temperature when the difference from the high-pressure saturation temperature detected by the condenser is less than a predetermined temperature, the control means When the correction in the correction means is performed, the frequency of the compressor is controlled to be the same as the frequency of the compressor when the control is performed based on the liquid temperature before correction. The correction liquid temperature is the liquid temperature. It said to be less than the opening degree of the expansion valve in the case of controlling on the basis of the liquid temperature before being corrected, and controls the opening degree of the expansion valve.

In this liquid cooling device, the opening of the expansion valve is controlled so that substantially all of the refrigerant evaporates in the evaporator based on the liquid temperature in the tank at that time. If the difference from the high-pressure saturation temperature detected by the container is less than the predetermined temperature, it is determined that liquid stagnation has occurred in the tank, and the opening of the expansion valve is lower than the liquid temperature in the tank at that time The opening is changed based on the corrected liquid temperature. Therefore, even when liquid stagnation occurs in the tank, the amount of refrigerant supplied to the evaporator becomes appropriate, and almost all of the refrigerant is evaporated in the evaporator, so that the compressor can be prevented from being broken.

In this liquid cooling device, when liquid stagnation occurs in the tank, the opening of the expansion valve is changed to be smaller than the opening corresponding to the liquid temperature in the tank at that time. The amount of refrigerant to be reduced is reduced. Therefore, even when liquid stagnation occurs in the tank, almost all of the refrigerant is evaporated in the evaporator, and the compressor can be prevented from being broken.

In this liquid cooling device, when liquid stagnation occurs in the tank, the frequency of the compressor is changed when the opening of the expansion valve is changed to be smaller than the opening corresponding to the liquid temperature in the tank at that time. Therefore, it is easy to control so that substantially all of the refrigerant is evaporated in the evaporator.
According to a second aspect of the present invention, there is provided the liquid cooling apparatus according to the first aspect, wherein the control means is based on the liquid temperature before the correction liquid temperature is corrected as the liquid temperature when the correction by the correction means is performed. After the opening degree of the expansion valve is controlled so as to be smaller than the opening degree of the expansion valve in the case of control, the frequency of the compressor is increased when the control is performed based on the liquid temperature before being corrected. Further, the frequency of the compressor is controlled.
In this liquid cooling device, when liquid stagnation occurs in the tank, the opening of the expansion valve
Is changed to be smaller than the opening corresponding to the liquid temperature in the tank at that time, then the compressor frequency
Is increased so that the capacity of the liquid
Thus, it can be controlled so that substantially all of the refrigerant is evaporated.

A liquid cooling apparatus according to a third aspect of the present invention includes a refrigerant circuit connected to a compressor, a condenser, an expansion valve, and an evaporator, a tank that contains a liquid in which the evaporator is disposed, and a liquid in the tank Temperature detecting means for detecting the temperature of the compressor, control means for controlling the frequency of the compressor and the opening of the expansion valve based on the liquid temperature detected by the temperature detecting means, and the discharge pipe temperature of the compressor, Correction means for correcting the liquid temperature detected by the temperature detection means to a lower correction liquid temperature when the difference from the high-pressure saturation temperature detected by the condenser is less than a predetermined temperature, the control means Controls the frequency of the compressor so that when the correction by the correction means is performed, the frequency of the compressor is increased based on the liquid temperature before correction, and the correction liquid The temperature is corrected as the liquid temperature. To be smaller than the opening degree of the expansion valve in the case of controlling on the basis of the previous liquid temperature that, and controls the opening degree of the expansion valve.

In this liquid cooling device, the opening degree of the expansion valve is determined based on the liquid temperature in the tank at that time.
The refrigerant is controlled so that almost all of the refrigerant evaporates, but it is checked with the discharge pipe temperature of the compressor and the condenser.
If the difference from the known high-pressure saturation temperature is less than the specified temperature, liquid stagnation in the tank
The expansion valve opening is based on a corrected fluid temperature that is lower than the fluid temperature in the tank at that time.
The opening is changed. Therefore, even if liquid stagnation occurs in the tank,
Therefore, the amount of refrigerant supplied to the evaporator becomes appropriate, and almost all of the refrigerant is evaporated in the evaporator.
Therefore, it is possible to prevent the compressor from being broken.
In this liquid cooling device, when liquid stagnation occurs in the tank, the opening of the expansion valve
However, since the opening is changed to be smaller than the opening corresponding to the liquid temperature in the tank at that time,
The amount of refrigerant supplied decreases. Therefore, if liquid stagnation occurs in the tank,
Even in the case, almost all of the refrigerant will be evaporated in the evaporator, preventing the compressor from breaking
it can.
In this liquid cooling device, when liquid stagnation occurs in the tank, the opening of the expansion valve is changed to be smaller than the opening corresponding to the liquid temperature in the tank at that time, and the frequency of the compressor increases. Therefore, it is possible to control so that substantially all of the refrigerant is evaporated in the evaporator without reducing the capacity of the liquid cooling device.

According to a fourth aspect of the present invention, in the liquid cooling device according to any one of the first to third aspects, the correction in the correction means is performed by the discharge pipe temperature of the compressor and the high-pressure saturation temperature detected by the condenser. The process is repeated until the difference reaches a predetermined temperature or more.

In this liquid cooling device, correction of the liquid temperature in the tank is repeated until the refrigerant is properly evaporated in the evaporator, so that the stagnation of liquid in the tank prevents the compressor from being broken. it can.

Liquid cooling device according to the fifth aspect based on the fourth aspect, the correction interval in said correcting means is shorter as the difference between the high-pressure saturation temperature is small to be detected by the discharge pipe temperature and the condenser of the compressor It is characterized by that.

In this liquid cooling device, the smaller the difference between the compressor discharge pipe temperature and the high-pressure saturation temperature detected by the condenser, the greater the stagnation of the liquid in the tank. Done in
A liquid cooling device according to a sixth aspect of the present invention includes a refrigerant circuit connected to a compressor, a condenser, an expansion valve, and an evaporator, a tank that contains a liquid in which the evaporator is disposed, and a liquid in the tank Temperature detecting means for detecting the temperature of the compressor, control means for controlling the frequency of the compressor and the opening of the expansion valve based on the liquid temperature detected by the temperature detecting means, and the discharge pipe temperature of the compressor, Correction means for correcting the liquid temperature detected by the temperature detection means to a lower correction liquid temperature when the difference from the high-pressure saturation temperature detected by the condenser is less than a predetermined temperature, the control means When the correction in the correction means is performed, the opening of the expansion valve is controlled using the correction liquid temperature as the liquid temperature, and the correction in the correction means is detected by the discharge pipe temperature of the compressor and the condenser. The difference from the high pressure saturation temperature Repeated until the above temperature, the correction interval in said correction means is characterized by short as the difference between the high-pressure saturation temperature detected by the discharge pipe temperature and the condenser of the compressor is small.
In this liquid cooling device, the opening degree of the expansion valve is determined based on the liquid temperature in the tank at that time.
The refrigerant is controlled so that almost all of the refrigerant evaporates, but it is checked with the discharge pipe temperature of the compressor and the condenser.
If the difference from the known high-pressure saturation temperature is less than the specified temperature, liquid stagnation in the tank
The expansion valve opening is based on a corrected fluid temperature that is lower than the fluid temperature in the tank at that time.
The opening is changed. Therefore, even if liquid stagnation occurs in the tank,
Therefore, the amount of refrigerant supplied to the evaporator becomes appropriate, and almost all of the refrigerant is evaporated in the evaporator.
Therefore, it is possible to prevent the compressor from being broken.
In this liquid cooling device, the liquid temperature in the tank is kept until the refrigerant is properly evaporated in the evaporator.
Since corrections are repeated, liquid stagnation occurs in the tank,
It is possible to prevent the compressor from being broken.
In this liquid cooling device, the difference between the discharge pipe temperature of the compressor and the high-pressure saturation temperature detected by the condenser is
The smaller the value, the larger the liquid stagnation in the tank.
Performed at short intervals.

  As described above, according to the present invention, the following effects can be obtained.

In the first invention, the opening degree of the expansion valve is controlled so that substantially all of the refrigerant evaporates in the evaporator based on the liquid temperature in the tank at that time. If the difference from the high-pressure saturation temperature detected by the container is less than the predetermined temperature, it is determined that liquid stagnation has occurred in the tank, and the opening of the expansion valve is lower than the liquid temperature in the tank at that time The opening is changed based on the corrected liquid temperature. Therefore, even when liquid stagnation occurs in the tank, the amount of refrigerant supplied to the evaporator becomes appropriate, and almost all of the refrigerant is evaporated in the evaporator, so that the compressor can be prevented from being broken.

In the first invention, when liquid stagnation occurs in the tank, the opening of the expansion valve is
Since the opening is changed to be smaller than the opening corresponding to the liquid temperature in the tank at that time, the amount of refrigerant supplied to the evaporator is reduced. Therefore, even when liquid stagnation occurs in the tank, almost all of the refrigerant is evaporated in the evaporator, and the compressor can be prevented from being broken.

In the first invention, when liquid stagnation occurs in the tank, the opening of the expansion valve is
Since the frequency of the compressor is not changed when the opening is changed to be smaller than the opening corresponding to the liquid temperature in the tank at that time, it is easy to control so that substantially all of the refrigerant is evaporated in the evaporator.

In the second invention, when liquid stagnation occurs in the tank, the opening of the expansion valve is
Since the frequency of the compressor is changed after the opening degree is changed to be smaller than the opening degree corresponding to the liquid temperature in the tank at that time, the refrigerant is not reduced in the evaporator without reducing the capacity of the liquid cooling device. It is possible to control so that almost all of is evaporated.

In the third invention, the opening degree of the expansion valve is determined in the evaporator based on the liquid temperature in the tank at that time.
And almost all of the refrigerant is controlled to evaporate, but it is detected by the compressor discharge pipe temperature and the condenser.
If the difference from the high-pressure saturation temperature is less than the specified temperature, liquid stagnation occurs in the tank.
The expansion valve opening is based on a corrected fluid temperature that is lower than the fluid temperature in the tank at that time.
The opening is changed. Therefore, even if liquid stagnation occurs in the tank,
Whether the amount of refrigerant supplied to the generator is appropriate and almost all of the refrigerant is evaporated in the evaporator
Therefore, it is possible to prevent the compressor from being broken.
In the third invention, when liquid stagnation occurs in the tank, the opening of the expansion valve is
Since the opening is changed to be smaller than the opening corresponding to the liquid temperature in the tank at that time, it is supplied to the evaporator.
The amount of refrigerant to be reduced is reduced. Therefore, when liquid stagnation occurs in the tank,
However, almost all of the refrigerant is evaporated in the evaporator, preventing the compressor from being broken.
The
In the third invention, when liquid stagnation occurs in the tank, the opening degree of the expansion valve is changed to be smaller than the opening degree corresponding to the liquid temperature in the tank at that time, and the frequency of the compressor increases. Therefore, it is possible to control so that substantially all of the refrigerant is evaporated in the evaporator without reducing the capacity of the liquid cooling device.
In the fourth invention, the correction of the liquid temperature in the tank is repeated until the refrigerant is properly evaporated in the evaporator, thereby preventing the compressor from being broken by the occurrence of liquid stagnation in the tank. it can.

In the fifth aspect of the invention, the smaller the difference between the discharge pipe temperature of the compressor and the high-pressure saturation temperature detected by the condenser, the larger the stagnation of the liquid in the tank. Done in
In the sixth invention, the opening degree of the expansion valve is controlled so that substantially all of the refrigerant evaporates in the evaporator based on the liquid temperature in the tank at that time. If the difference from the high-pressure saturation temperature detected by the container is less than the predetermined temperature, it is determined that liquid stagnation has occurred in the tank, and the opening of the expansion valve is lower than the liquid temperature in the tank at that time The opening is changed based on the corrected liquid temperature. Therefore, even when liquid stagnation occurs in the tank, the amount of refrigerant supplied to the evaporator becomes appropriate, and almost all of the refrigerant is evaporated in the evaporator, so that the compressor can be prevented from being broken.
In the sixth aspect of the invention, the correction of the liquid temperature in the tank is repeated until the refrigerant is properly evaporated in the evaporator, thereby preventing the compressor from being broken by the occurrence of liquid stagnation in the tank. it can.
In the sixth aspect of the invention, the smaller the difference between the discharge pipe temperature of the compressor and the high-pressure saturation temperature detected by the condenser, the greater the stagnation of the liquid in the tank. Done in

It is a lineblock diagram of the liquid cooling device concerning a 1st embodiment of the present invention. It is a control block diagram of the liquid cooling device of FIG. It is a figure which shows the relationship between a compressor frequency and the opening degree of an expansion valve. It is a figure explaining the control method in the liquid cooling device of FIG. It is a figure explaining the example of control in the liquid cooling device of FIG.

  Hereinafter, embodiments of a liquid cooling apparatus according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, the liquid cooling device 1 (immersion type liquid cooling device) of this embodiment has a refrigerant circuit to which a compressor 2, a condenser 3, an expansion valve 4 and an evaporator 5 are connected. . In this refrigerant circuit, a condenser 3 is connected to the discharge port of the compressor 2, and an expansion valve 4 is connected to the condenser 3. Then, one end of the evaporator 5 is connected to the expansion valve 4, and the suction port of the compressor 2 is connected to the other end of the evaporator 5 via the accumulator 6. In this way, a refrigerant discharged from the compressor 2 flows in order to the condenser 3, the expansion valve 4, and the evaporator 5, and a cooling cycle is formed that returns to the compressor 2 via the accumulator 6.

The liquid cooling device 1 has a device main body 8 that houses the compressor 2, the condenser 3, and the expansion valve 4, and the evaporator 5 is disposed below the device main body 8. Is tank T
It is immersed in the working fluid (liquid) stored in the inside. In addition, a blower fan 7 that supplies an air flow to the condenser 3, a control unit 12, and the like are disposed in the apparatus main body 8.

Therefore, in the liquid cooling device 1, the working fluid is cooled in the tank T. The tank T is provided with, for example, a pump for conveying the working fluid. As shown in FIG. 1, the working fluid discharged from the machine tool is supplied into the tank T by driving the pump. The machining fluid cooled in the tank T is supplied to the machine tool.

The evaporator 5 is configured as a coil part that is immersed in the working fluid stored in the tank T and spirally wound along the vertical direction.

In the liquid cooling apparatus 1, as shown in FIG. 1, a liquid temperature thermistor Ta for detecting the liquid temperature (working fluid temperature) around the evaporator 5 is disposed in the tank T. In the discharge pipe of the compressor 2,
A discharge pipe thermistor Tb is disposed, and a condenser temperature thermistor Tc is disposed in the condenser 3.

The control unit 12 of the liquid cooling apparatus 1 includes a target temperature storage unit 101, a compressor control unit 102,
The determination unit 103, the correction unit 104, the liquid temperature storage unit 105, and the expansion valve control unit 106 are included. Further, a controller, a liquid temperature thermistor Ta, a discharge pipe thermistor Tb, a condenser thermistor Tc, a compressor 2 and an expansion valve 4 are connected to the controller 12.

The target temperature storage unit 101 stores the target temperature when the user inputs the target temperature of the liquid in the tank by operating the controller.

The compressor control unit 102 includes the liquid temperature detected by the liquid temperature thermistor Ta and the target temperature storage unit 10.
A capacity command value is determined based on the target temperature stored in 1, and the compressor is controlled to a frequency corresponding to the capacity command value.

In this embodiment, when it is not determined that liquid stagnation occurs in the tank,
The compressor control unit 102 controls the frequency of the compressor 2 based on the liquid temperature detected by the liquid temperature thermistor Ta. On the other hand, when it is determined that liquid stagnation occurs in the tank, the compressor control unit 102 controls the frequency of the compressor 2 based on the liquid temperature detected by the liquid temperature thermistor Ta. However, when the opening of the expansion valve is controlled to be small based on the correction fluid temperature,
The frequency of the compressor 2 is maintained without being changed. Further, when the opening degree of the expansion valve 4 is controlled to be small until there is no liquid stagnation in the tank, the correction of the opening degree of the expansion valve 4 is started assuming that the stagnation has occurred in the tank. It is increased until the frequency at which substantially the same capacity as that of the previous liquid cooling device is output is obtained.

The determination unit 103 determines the discharge temperature detected by the discharge pipe thermistor Tb and the condenser thermistor T.
Based on the refrigerant high-pressure saturation temperature detected in c, it is determined whether liquid stagnation is occurring in the tank. In the present embodiment, the determination unit 103 determines that the temperature difference between the discharge temperature detected by the discharge pipe thermistor Tb and the refrigerant high-pressure saturation temperature detected by the condenser thermistor Tc is the first.
When the temperature is lower than a predetermined temperature (for example, 10 ° C.), it is determined that liquid stagnation occurs in the tank. The determination unit 103 determines whether liquid stagnation has occurred in the tank until the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is equal to or higher than the first predetermined temperature and the stagnation is eliminated in the tank.

After the opening degree of the expansion valve 4 is controlled based on the corrected liquid temperature, the determination unit 103 performs a first period (example:
1 second) or every second period (eg 10 seconds), it is determined whether liquid stagnation has occurred in the tank. In the determination unit 103, the determination interval differs depending on whether the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is smaller than the second predetermined temperature or higher than the second predetermined temperature. That is, when the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is smaller than the second predetermined temperature, the stagnation of the liquid in the tank is large, so by correcting the opening of the expansion valve 4 small at short intervals, Even if the liquid in the tank is stagnant, the refrigerant is properly evaporated in the evaporator. On the other hand, when the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is equal to or higher than the second predetermined temperature, since the stagnation of the liquid in the tank is small, the opening of the expansion valve 4 is corrected to be small at long intervals. As a result, even if the liquid in the tank is stagnant, the refrigerant is appropriately evaporated in the evaporator. Thus, the correction interval of the opening degree of the expansion valve 4 differs depending on whether the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is smaller than the second predetermined temperature or higher than the second predetermined temperature.

Therefore, in the present embodiment, the second predetermined temperature is a temperature lower than 10 ° C. which is the first predetermined temperature, and when the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is smaller than the second predetermined temperature,
After the opening degree of the expansion valve is controlled based on the correction liquid temperature, the determination is made again when the first period has elapsed. On the other hand, when the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is equal to or higher than the second predetermined temperature, the second period elapses after the opening degree of the expansion valve is controlled based on the corrected liquid temperature. Judge again. In the present embodiment, since the first period is shorter than the second period, the correction interval when the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is small is shorter than the correction interval when the temperature difference is large.

The correction unit 104 corrects the liquid temperature detected by the liquid temperature thermistor Ta when the determination unit 103 determines that liquid stagnation is occurring in the tank. In the present embodiment, the correction unit 104 determines a predetermined correction temperature (for example, 0. 0) from the liquid temperature detected by the liquid temperature thermistor Ta.
The temperature is corrected by 1 ° C).

The liquid temperature storage unit 105 stores a liquid temperature used when the expansion valve control unit 106 controls the expansion valve 4. In the present embodiment, when the determination unit 103 does not determine that liquid stagnation has occurred in the tank, the liquid temperature storage unit 105 stores the liquid temperature detected by the liquid temperature thermistor Ta as the liquid temperature. To do. On the other hand, when the determination unit 103 determines that liquid stagnation is occurring in the tank, the liquid temperature storage unit 105 stores the corrected liquid temperature corrected by the correction unit 104 as the liquid temperature. .

The expansion valve control unit 106 opens the opening of the expansion valve 4 based on the liquid temperature stored in the liquid temperature storage unit 105 and the compressor frequency corresponding to the capacity command value detected by the compressor control unit 102. To control. Therefore, as shown in FIG. 3, the expansion valve control unit 106 stores the relationship between the compressor frequency and the opening degree of the expansion valve for each liquid temperature in the tank. Be controlled.

In FIG. 3, the horizontal axis represents the compressor frequency, and the vertical axis represents the expansion valve opening. In FIG. 3, when the liquid temperature is 0 ° C., 10 ° C., 20 ° C., 30 ° C., 40 ° C., 50 ° C., the refrigerant supplied to the evaporator 5 exchanges heat with the liquid in the tank, so that the refrigerant The relationship between the compressor frequency and the opening degree of the expansion valve when almost all of is evaporated is shown. As shown in FIG. 3, the expansion valve opening increases as the compressor frequency increases, and the expansion valve opening increases as the liquid temperature increases.

  The control method in the liquid cooling device 1 of this embodiment is demonstrated based on FIG.

First, the user inputs the target temperature of the liquid in the tank by operating the controller (step S1). Then, the compressor is controlled according to the frequency of the compressor corresponding to the capability command value based on the liquid temperature detected by the liquid temperature thermistor Ta and the target temperature input by the user (step S2), and the liquid temperature thermistor Ta The opening degree of the expansion valve is controlled based on the detected liquid temperature and the frequency of the compressor corresponding to the capacity command value (step S3). That is, as shown in FIG. 3, the opening degree of the expansion valve corresponding to the frequency of the compressor corresponding to the capacity command value is controlled in the relationship corresponding to the liquid temperature detected by the liquid temperature thermistor Ta.

Thereafter, whether liquid stagnation has occurred in the tank based on the discharge temperature detected by the discharge pipe thermistor Tb and the refrigerant high pressure saturation temperature detected by the condenser temperature thermistor Tc (discharge temperature and refrigerant high pressure saturation temperature). Whether or not the temperature difference between and is smaller than the first predetermined temperature) is repeatedly determined (step S4). When the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is smaller than the first predetermined temperature (S4: YES), the liquid temperature stored in the liquid temperature storage unit 105 is determined to indicate that liquid stagnation has occurred in the tank. The correction temperature is corrected to a lower correction temperature, and the correction liquid temperature is stored as the liquid temperature in the liquid temperature storage unit 105 (step S5). Thereafter, the opening degree of the expansion valve is controlled based on the corrected liquid temperature stored as the liquid temperature in the liquid temperature storage unit 105 (step S6).

Thereafter, it is determined whether the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is smaller than the second predetermined temperature (step S7). When it is determined that the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is smaller than the second predetermined temperature (S7: YES), after it is determined in step S4 that liquid stagnation is occurring in the tank, It is repeatedly determined whether the first period has elapsed (step S8). When the first period has elapsed (S7: YES), the process proceeds to step S4 and the same process is repeated.

On the other hand, if it is not determined in step S7 that the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is smaller than the second predetermined temperature (S7: NO), liquid stagnation occurs in the tank in step S4. After it is determined that the second period has elapsed, it is repeatedly determined whether the second period has elapsed (step S9). If the second period has elapsed (S9: YES), step S4
The same process is repeated.

In step S4, when it is not determined that the temperature difference between the discharge temperature and the refrigerant high-pressure saturation temperature is smaller than the first predetermined temperature (S4: NO), since the refrigerant is appropriately evaporated in the evaporator, the liquid temperature storage unit Without correcting the liquid temperature stored in 105, the process proceeds to step S10.

In step S10, it is determined whether the stagnation of the liquid has occurred in the tank, or whether the opening degree of the expansion valve has been corrected (step S10). If it is determined in step S10 that the opening degree of the expansion valve has been corrected (S10: YES), the frequency of the compressor is increased based on the relationship between the liquid temperature and the target temperature at that time (step S11). At this time, the opening degree of the expansion valve is changed based on the correction fluid temperature at that time as the frequency of the compressor is increased. Therefore, when the stagnation of the liquid occurs in the tank, the opening degree of the expansion valve is changed to a small value, but the capacity of the liquid cooling device is maintained substantially the same as before the stagnation of the liquid occurs in the tank. . Thereafter, the process proceeds to step 4 and the same processing is repeated.

On the other hand, when it is not determined in step S10 that the opening degree of the expansion valve has been corrected (S10: NO), the process proceeds to step 4 and the same process is repeated. Step S1
At 0, it is determined that the opening degree of the expansion valve has been corrected because the stagnation of the liquid has occurred in the tank, after the opening degree of the expansion valve has been corrected, and the frequency of the compressor in step S11. This is the state before increasing. Therefore, when the control for increasing the frequency of the compressor is performed in step S11, it is reset that the opening degree of the expansion valve is corrected on the assumption that liquid stagnation has occurred in the tank.

  An example of control in the liquid cooling apparatus 1 of the present embodiment will be described with reference to FIG.

At present, in the state A1 (liquid temperature T1, opening degree a1, frequency c1) in FIG. 5, when liquid stagnation occurs in the tank, the current liquid temperature T1 is reduced to a correction liquid temperature T2 that is lower by a predetermined correction temperature. The current opening degree a1 of the expansion valve is changed to the corrected opening degree a2 while being corrected and the current frequency c1 is maintained.

When it is determined that the refrigerant is not properly evaporated in the evaporator due to stagnation of the liquid in the tank after being changed to the state A2 (liquid temperature T2, opening degree a2, frequency c1) in FIG.
The correction fluid temperature T2 is corrected to the correction fluid temperature T3 that is lower by the predetermined correction temperature, and the current opening degree a2 of the expansion valve is changed to the correction opening degree a3 while the current frequency c1 is maintained.

After changing to the state A3 (liquid temperature T3, opening degree a3, frequency c1) in FIG. 5, when the refrigerant is properly evaporated in the evaporator, the frequency of the compressor is based on the relationship between the liquid temperature and the target temperature. Change,
Further, the opening degree of the expansion valve is changed according to the relationship between the compressor frequency at the correction liquid temperature T3 and the opening degree of the expansion valve, and the state A4 (liquid temperature T3, frequency c2) in FIG. 5 is obtained.

As shown in FIG. 5, the state A1 (liquid temperature T1, opening degree a1, frequency c1) in FIG. 5 and the state A4 (liquid temperature T3, opening degree a3, frequency c1) in FIG. Are on the same capacity line and have almost the same ability.

<Characteristics of the liquid cooling device of this embodiment>
The liquid cooling device 1 of the present embodiment has the following features.

In the liquid cooling device 1 of the present embodiment, the opening degree of the expansion valve 4 is controlled so that substantially all of the refrigerant evaporates in the evaporator 5 based on the liquid temperature in the tank T at that time. When the temperature difference between the discharge pipe temperature of the machine 2 and the high-pressure saturation temperature detected by the condenser 3 is less than the first predetermined temperature,
It is determined that liquid stagnation has occurred in the tank T, and the opening of the expansion valve 4 is changed to an opening based on a corrected liquid temperature lower than the liquid temperature in the tank T at that time. Therefore, even when liquid stagnation occurs in the tank T, the amount of refrigerant supplied to the evaporator 5 becomes appropriate, and almost all of the refrigerant is evaporated in the evaporator 5, so that liquid refrigerant is supplied to the compressor 2. By being sucked, it is possible to prevent the compressor 2 from being broken.

In the liquid cooling device 1 of the present embodiment, when stagnation of liquid occurs in the tank T,
Since the opening degree of the expansion valve 4 is changed to be smaller than the opening degree corresponding to the liquid temperature in the tank T at that time, the amount of refrigerant supplied to the evaporator 5 is reduced. Therefore, even when liquid stagnation occurs in the tank T, almost all of the refrigerant is evaporated in the evaporator 5,
By sucking the liquid refrigerant into the compressor 2, it is possible to prevent the compressor 2 from being broken.

In the liquid cooling device 1 of the present embodiment, when stagnation of liquid occurs in the tank T,
Since the opening degree of the expansion valve 4 is changed to be smaller than the opening degree corresponding to the liquid temperature in the tank T at that time, the frequency of the compressor 2 is changed so as to increase. It is possible to control so that substantially all of the refrigerant is evaporated in the evaporator 5 without lowering.

In the liquid cooling device 1 of the present embodiment, the liquid temperature in the tank T is repeatedly corrected until the liquid stagnation does not occur in the tank T. Therefore, the liquid stagnation occurs in the tank T. Thus, the compressor can be prevented from being broken.

In the liquid cooling device 1 of this embodiment, the smaller the difference between the discharge pipe temperature of the compressor 2 and the high-pressure saturation temperature detected by the condenser 3, the greater the stagnation of the liquid in the tank T. The liquid temperature is corrected at short intervals.

In a conventional liquid cooling device, as in the case where stagnation of liquid occurs in the tank, even when dirt accumulates on the surface of the evaporator disposed in the tank, almost all of the refrigerant is not evaporated in the evaporator. In addition, there is a technical problem that the compressor breaks when the liquid refrigerant is sucked into the compressor. However, in the liquid cooling device 1 of the present embodiment, dirt may accumulate on the surface of the evaporator disposed in the tank. , Can prevent the compressor from breaking.

As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

In the above-described embodiment, when the stagnation of the liquid is generated in the tank, the case where the opening degree of the expansion valve is changed small while the frequency of the compressor is maintained is described. Simultaneously with a small change, the frequency of the compressor may be increased.

In the above-described embodiment, when the stagnation of liquid occurs in the tank, the frequency of the compressor is increased after the opening of the expansion valve is changed to be small while the frequency of the compressor is maintained. As described above, the frequency of the compressor does not have to be increased after the opening of the expansion valve is changed to be small.

In the above-described embodiment, the case where the correction interval for the opening degree of the expansion valve is different based on the temperature difference between the discharge temperature and the high-pressure saturation temperature has been described. However, the correction interval for the opening degree of the expansion valve is different from the discharge temperature and the high-pressure saturation temperature. It may be the same regardless of the temperature difference.

If the present invention is used, it is possible to prevent the compressor from being broken by sucking the liquid refrigerant into the compressor.

DESCRIPTION OF SYMBOLS 1 Liquid cooling device 2 Compressor 3 Condenser 4 Expansion valve 5 Evaporator 12 Control part (control means)
104 Correction unit (correction means)
T Tank Ta Liquid temperature thermistor (temperature detection means)

Claims (6)

A refrigerant circuit connecting a compressor, a condenser, an expansion valve and an evaporator;
A tank for storing a liquid disposed in the evaporator;
Temperature detecting means for detecting the temperature of the liquid in the tank;
Control means for controlling the frequency of the compressor and the opening of the expansion valve based on the liquid temperature detected by the temperature detection means;
When the difference between the discharge pipe temperature of the compressor and the high-pressure saturation temperature detected by the condenser is less than a predetermined temperature, the liquid temperature detected by the temperature detecting means is corrected to a correction liquid temperature lower than that. Means and
When the correction in the correction unit is performed, the control unit adjusts the frequency of the compressor so as to be the same as the frequency of the compressor in the case of controlling based on the liquid temperature before correction. And controlling the opening of the expansion valve so as to be smaller than the opening of the expansion valve when controlling based on the liquid temperature before the correction liquid temperature is corrected as the liquid temperature. Liquid cooling device. When the correction in the correction unit is performed, the control unit is configured to be smaller than the opening degree of the expansion valve when controlling based on the liquid temperature before the correction liquid temperature is corrected as the liquid temperature. The frequency of the compressor is controlled to be higher than the frequency of the compressor when controlling based on the liquid temperature before being corrected after controlling the opening degree of the expansion valve. liquid cooling device according to 1. A refrigerant circuit connecting a compressor, a condenser, an expansion valve and an evaporator;
A tank for storing a liquid disposed in the evaporator;
Temperature detecting means for detecting the temperature of the liquid in the tank;
Control means for controlling the frequency of the compressor and the opening of the expansion valve based on the liquid temperature detected by the temperature detection means;
When the difference between the discharge pipe temperature of the compressor and the high-pressure saturation temperature detected by the condenser is less than a predetermined temperature, the liquid temperature detected by the temperature detecting means is corrected to a correction liquid temperature lower than that. Means and
The control means controls the frequency of the compressor so that when the correction by the correction means is performed , the frequency of the compressor is higher than the frequency of the compressor when the control is performed based on the liquid temperature before correction. The liquid cooling is characterized in that the opening degree of the expansion valve is controlled to be smaller than the opening degree of the expansion valve when the correction liquid temperature is controlled based on the liquid temperature before being corrected as the liquid temperature. apparatus. Correction in the correcting means, claim 1 3, the difference between the high-pressure saturation temperature detected by the discharge pipe temperature and the condenser of the compressor is characterized in that repeated until a predetermined temperature or higher The liquid cooling device described in 1. The liquid cooling device according to claim 4 , wherein the correction interval in the correction unit is shorter as the difference between the discharge pipe temperature of the compressor and the high-pressure saturation temperature detected by the condenser is smaller. A refrigerant circuit connecting a compressor, a condenser, an expansion valve and an evaporator;
A tank for storing a liquid disposed in the evaporator;
Temperature detecting means for detecting the temperature of the liquid in the tank;
Control means for controlling the frequency of the compressor and the opening of the expansion valve based on the liquid temperature detected by the temperature detection means;
When the difference between the discharge pipe temperature of the compressor and the high-pressure saturation temperature detected by the condenser is less than a predetermined temperature, the liquid temperature detected by the temperature detecting means is corrected to a correction liquid temperature lower than that. Means and
When the correction in the correction unit is performed, the control unit controls the opening of the expansion valve using the correction liquid temperature as the liquid temperature ,
The correction in the correction means is repeated until the difference between the discharge pipe temperature of the compressor and the high-pressure saturation temperature detected by the condenser is equal to or higher than a predetermined temperature,
The liquid cooling device according to claim 1, wherein the correction interval in the correction means is shorter as the difference between the discharge pipe temperature of the compressor and the high-pressure saturation temperature detected by the condenser is smaller .

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