Mold cooling system, mold cooling method

Abstract

This invention provides a mold cooling system and method that can detect the boiling of the liquid refrigerant used to cool the mold at an early stage and control the cooling conditions of the mold. [Solution] The mold cooling system according to the present disclosure is a mold cooling system that cools a mold by flowing a liquid refrigerant through a refrigerant channel formed in the mold, and comprises a pressure acquisition means for acquiring the pressure value of the refrigerant in the refrigerant channel, and a boiling determination means for determining whether or not the refrigerant is boiling based on the pressure value, wherein if the pressure value exceeds a threshold, the boiling determination means determines that the refrigerant has boiled.

Description

[Technical Field]

[0001] This disclosure relates to a mold cooling system and a mold cooling method. [Background technology]

[0002] Patent Document 1 discloses a temperature control method for a casting mold, which determines whether or not the cooling water is boiling based on the mold temperature near a point in the cooling water passage of the casting mold where boiling of the cooling water may occur, and the amount of cooling water discharged at the outlet side of the cooling water passage. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2014-108434 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, the temperature control method for casting molds disclosed in Patent Document 1 makes it difficult to accurately measure the mold temperature. Therefore, it has been difficult to accurately and quickly determine whether the cooling water is boiling based on the mold temperature.

[0005] This disclosure has been made in view of the above circumstances and provides a mold cooling system and mold cooling method that can detect the boiling of a liquid refrigerant used to cool a mold at an early stage and control the cooling conditions of the mold. [Means for solving the problem]

[0006] A mold cooling system according to one aspect of this disclosure is: A mold cooling system that cools a mold by flowing a liquid coolant through a coolant channel formed in the mold, A pressure acquisition means for acquiring the pressure value of the refrigerant in the refrigerant flow path, Boiling determination means for determining the presence or absence of boiling of the refrigerant based on the pressure value, and when the pressure value exceeds a threshold value, the boiling determination means determines that the refrigerant has boiled.

[0007] A mold cooling method according to an aspect of the present disclosure is a mold cooling method for cooling a mold by flowing a liquid refrigerant through a refrigerant flow path formed in the mold, a pressure acquisition step of acquiring a pressure value of the refrigerant in the refrigerant flow path, a boiling determination step of determining the presence or absence of boiling of the refrigerant based on the pressure value, a flow rate control step of controlling the flow rate of the refrigerant flowing through the refrigerant flow path when it is determined in the boiling determination step that the refrigerant has boiled, and in the boiling determination step, when the pressure value exceeds a threshold value, it is determined that the refrigerant has boiled.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a mold cooling system and a mold cooling method capable of detecting the boiling of a liquid refrigerant for cooling a mold at an early stage and controlling the cooling conditions of the mold.

Brief Description of the Drawings

[0009] [Figure 1] It is a block diagram of a mold cooling system according to an embodiment of the present disclosure. [Figure 2] It is a graph showing the relationship between the elapsed time of a mold, the temperature in the refrigerant flow path, and the pressure in the refrigerant flow path according to an embodiment of the present disclosure. [Figure 3] It is a flowchart showing a mold cooling method according to an embodiment of the present disclosure.

Modes for Carrying Out the Invention

[0010] Hereinafter, specific embodiments of the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Also, for clarity of explanation, the following description and the drawings are simplified as appropriate.

[0011] <Die Cooling System> FIG. 1 is a block diagram of a die cooling system according to an embodiment of the present disclosure. The die cooling system 1 includes a die 11, a refrigerant supply means 12, a pressure sensor 13, a boiling determination means 14, a flow control means 15, and a flow measurement means 16. The die 11 has refrigerant channels 111 to 113. Note that the pressure sensor 13 is a pressure acquisition means.

[0012] The die 11 is, for example, a die-casting die, has a cavity (not shown), and molten metal is poured into the cavity. The poured molten metal is cooled and solidified, and then taken out from the die 11 as a casting. The material of the die 11 is, for example, an iron-based metal such as carbon steel, cast steel, cast iron, or hot work tool steel. Note that the size of the die 11 is appropriately determined according to the size of the target casting. Also, the material of the metal poured into the die 11 is, for example, an alloy such as an aluminum alloy, a zinc alloy, or a magnesium alloy.

[0013] The refrigerant channels (flow paths) 111 to 113 are provided so as to pass through the inside of the die 11 and are connected to the refrigerant supply means 12. In the refrigerant channels 111 to 113, the liquid refrigerant received from the refrigerant supply means 12 flows through the inside, and the refrigerant cools the die 11. The material of the refrigerant channels 111 to 113 is, for example, a metal pipe such as a steel pipe, a stainless steel pipe, or a copper pipe.

[0014] The mold cooling system 1 shown in Figure 1 is equipped with three refrigerant passages 111, 112, and 113. However, the number of refrigerant passages may be two or fewer, or four or more. The number, inner diameter, and position of the refrigerant passages are determined according to the desired cooling conditions or the location of the cavity. Furthermore, the refrigerant flowing through refrigerant passages 111 to 113 may be any liquid, such as water. Rust inhibitors such as nitrite-based, chromate-based, molybdate-based, or zinc salt-based agents may be added to the water to function as a coolant.

[0015] The refrigerant supply means 12 is connected to the refrigerant flow paths 111-113 and the flow rate control means 15. The refrigerant supply means 12 supplies refrigerant to the refrigerant flow paths 111-113. The refrigerant supply means 12 is composed of, for example, a refrigerant tank and a mechanical pump. In addition, multiple refrigerant supply means 12 may be provided in the mold cooling system 1, and each may be connected to one of the refrigerant flow paths 111-113. Furthermore, the refrigerant supply means 12 may have a refrigerant circulation function that recovers the refrigerant after supply and supplies the recovered refrigerant back to the refrigerant flow paths 111-113. In addition, when circulating the refrigerant, the refrigerant supply means 12 may further have an impurity treatment function that removes impurities in the refrigerant that have been generated during circulation.

[0016] The pressure sensor 13 is connected to the refrigerant flow paths 111-113 and the boiling determination means 14. The pressure sensor 13 is placed within the refrigerant flow paths 111-113 and measures the pressure value within the refrigerant flow paths 111-113. The pressure sensor 13 can be, for example, a semiconductor pressure sensor, a thin-film pressure sensor, a strain gauge pressure sensor, or a capacitive pressure sensor. Alternatively, the pressure sensor 13 may be a pressure control valve having a mechanism that opens the valve when a certain pressure is detected. In this case, the pressure sensor 13 and the boiling determination means 14 may be configured as an integrated pressure control valve.

[0017] Multiple pressure sensors 13 may be placed within the refrigerant flow paths 111 to 113, and one or more may be placed in each of the refrigerant flow paths 111, 112, and 113. Furthermore, the preferred location for the pressure sensors 13 is within the refrigerant flow paths 111 to 113, close to the molten metal, where the refrigerant is likely to experience a temperature rise. Placing the pressure sensors 13 in a location where the refrigerant is likely to experience a temperature rise allows for earlier detection of refrigerant boiling.

[0018] The boiling determination means 14 is connected to the pressure sensor 13 and the flow rate control means 15. The boiling determination means 14 receives pressure value information of the refrigerant from the pressure sensor 13 and determines whether or not the refrigerant is boiling based on the received pressure value information. The boiling determination means 14 is composed of, for example, a CPU (Central Processing Unit), an MPU (Micro Processing Unit), working memory, and a non-volatile storage device that stores a control program. As mentioned above, the boiling determination means 14 may also be configured as a pressure control valve integrated with the pressure sensor 13.

[0019] Figure 2 is a graph showing the relationship between the elapsed time of the mold according to the present disclosure and the temperature and pressure within the refrigerant flow path. The solid line represents the change in refrigerant temperature over time in the refrigerant flow paths 111 to 113, and the dashed line represents the change in refrigerant pressure over time in the refrigerant flow paths 111 to 113.

[0020] In Figure 2(A), the temperature inside the refrigerant flow path remains almost constant at T1 (for example, if the refrigerant is water, T1 is approximately 100°C), but the pressure inside the refrigerant flow path rises rapidly. The boiling determination means 14 determines, for example, in Figure 2(A), when the refrigerant pressure reaches a threshold P A The system detects when the temperature exceeds a certain level and determines that the refrigerant has boiled.

[0021] Furthermore, in Figure 2(B), the temperature inside the refrigerant flow path remains almost constant T1, as in Figure 2(A), but the pressure inside the refrigerant flow path fluctuates wildly in a short period of time. The boiling determination means 14, for example, the time width t in Figure 2(B) B In this case, the pressure in the refrigerant flow path is the first pressure threshold P B1exceeds and is less than the second pressure threshold P B1 lower than, and it is detected that the refrigerant has boiled. Further, the boiling determination means 14 determines the maximum pressure value P B2 in the time width t B and the minimum pressure value P max of the pressure, receives them, and when the value of the pressure difference P max -P min exceeds the threshold value, it may be determined that the refrigerant has boiled.

[0022]

[0023] Note that the pressure thresholds P A [[ID=2`0]]P B1 and P[[ID=2`3]] B2 , the pressure difference P max -P min , and the time width t B are appropriately determined respectively as values capable of detecting the boiling of the refrigerant in the embodiments of the present disclosure. Further, the time-series data of the temperature and pressure in the refrigerant flow path are learned by artificial intelligence (AI: Artificial Intelligence), and based on the learned data, the pressure thresholds P A P B1 [[ID=3`4]]and P B2 , and the time width t B may be determined, and new boiling determination conditions may be derived based on the learned data.

[0023] The flow rate control means 15 is connected to the refrigerant supply means 12 and the boiling determination means 14. The flow rate control means 15 controls the refrigerant supply by the refrigerant supply means 12 based on the determination result of the boiling determination means 14. The flow rate control means 15 is composed of, for example, a CPU, an MPU, a working memory, and a non-volatile storage device storing a control program.

[0024] Furthermore, when the boiling detection means 14 detects boiling of the refrigerant, the flow rate control means 15 increases the flow rate of the refrigerant supplied by, for example, the refrigerant supply means 12. This suppresses the boiling of the refrigerant flowing through the refrigerant passages 111 to 113. If the refrigerant were to boil, the mold 11 would exchange heat with the gaseous refrigerant, and the heat transfer rate from the mold to the refrigerant would decrease significantly compared to when heat exchange occurs with the liquid refrigerant. As a result, the cooling efficiency of the mold 11 using the refrigerant would decrease significantly. In other words, by suppressing the boiling of the refrigerant, it is possible to suppress the decrease in the cooling efficiency of the mold 11.

[0025] Furthermore, the flow rate control means 15 may perform different flow rate control for each of the refrigerant flow paths 111, 112, and 113. For example, if it is determined that only the refrigerant in refrigerant flow path 111 has boiled, the flow rate of the refrigerant flowing through refrigerant flow path 111 may be increased, while the flow rates of the refrigerant flowing through refrigerant flow paths 112 and 113 may remain unchanged. Alternatively, if it is determined that only the refrigerant in refrigerant flow path 111 has boiled, the flow rate of the refrigerant flowing through refrigerant flow path 111 may be increased, while the flow rates of the refrigerant flowing through refrigerant flow paths 112 and 113 may be decreased, so as not to change the overall refrigerant flow rate. By performing different flow rate control for each of the refrigerant flow paths 111 to 113, it is possible to equalize the temperature of the mold 11 and improve the quality of the castings.

[0026] The flow rate measuring means 16 is positioned within the refrigerant flow paths 111 to 113. The flow rate measuring means 16 measures the flow rate of the refrigerant flowing through the refrigerant flow paths 111 to 113. If the refrigerant supply means 12 has a refrigerant circulation function, the flow rate measuring means 16 may be positioned within the flow path through which the refrigerant circulates. The flow rate measuring means 16 is, for example, an ultrasonic flow meter, an electromagnetic flow meter, a float flow meter, or a differential pressure flow meter.

[0027] As described above, the mold cooling system according to the embodiment of this disclosure measures the pressure of the refrigerant flowing through the refrigerant channel and detects boiling of the refrigerant based on the measured pressure value. This makes it possible to provide a mold cooling system that can detect the boiling of the liquid refrigerant used to cool the mold at an early stage and control the cooling conditions of the mold.

[0028] <Mold Cooling Method> Next, a mold cooling method according to an embodiment of the present disclosure will be described with reference to Figure 3. Figure 3 is a flowchart of the mold cooling method according to an embodiment of the present disclosure.

[0029] First, the pressure sensor 13 acquires the refrigerant pressure value in the refrigerant flow paths 111 to 113 (step S1). Here, the pressure sensor 13 may acquire the refrigerant pressure value continuously, or it may acquire the refrigerant pressure value at regular intervals. Furthermore, at times when the refrigerant is likely to boil, such as immediately after pouring molten metal into the mold 11, the frequency of acquiring the refrigerant pressure value may be increased compared to other times. In addition, at times when the refrigerant is unlikely to boil, such as immediately after removing the casting from the mold 11, the frequency of acquiring the refrigerant pressure value may be decreased compared to other times.

[0030] Next, the boiling determination means 14 receives the pressure value acquired by the pressure sensor 13 and determines whether the pressure value exceeds a threshold (step S2). If the pressure value does not exceed the threshold (No in step S2), the process proceeds to the next boiling determination step, step S3. On the other hand, if the pressure value exceeds the threshold (Yes in step S2), the process proceeds to step S5, which controls the flow rate of the refrigerant flowing through the refrigerant passages 111 to 113.

[0031] If the result in step S2 is No, the boiling determination means 14 determines whether the amount of fluctuation in the refrigerant pressure value exceeded a threshold within a predetermined time range (step S3). The determination in step S3 is, for example, based on the time range t in Figure 2 (B). B In this case, the pressure in the refrigerant flow path is the first pressure threshold P B1 It exceeds and P B1 A second pressure threshold P smaller than B2 It detects when the temperature falls below a certain level and determines that the refrigerant has boiled. Furthermore, the time interval t B Maximum pressure value P max and the minimum pressure P min Received, pressure difference P max -P minThe system may detect when the value exceeds a threshold and determine that the refrigerant has boiled.

[0032] In step S3, if the fluctuation amount of the refrigerant pressure value does not exceed a threshold within a predetermined time range (No in step S3), it is determined whether or not to terminate the cooling of the mold 11 (step S4). The determination of whether to terminate the cooling is made, for example, based on the progress of the casting process. If the cooling of the mold 11 is to be terminated (Yes in step S4), the process is terminated, and if the cooling of the mold 11 is to be continued (No in step S4), the process returns to step S1, and the refrigerant pressure value in the refrigerant flow paths 111 to 113 is obtained again.

[0033] On the other hand, if the amount of fluctuation in the refrigerant pressure value over a predetermined time period exceeds a threshold (Yes in step S3), the process proceeds to step S5, which controls the flow rate of the refrigerant flowing through the refrigerant passages 111 to 113.

[0034] If the result in step S2 or step S3 is determined to be Yes, the flow rate control means 15 controls the flow rate of the refrigerant flowing through the refrigerant passages 111 to 113 (step S5). After controlling the flow rate of the refrigerant in step S5, the process returns to step S1, and the pressure value of the refrigerant in the refrigerant passages 111 to 113 is obtained again.

[0035] As described above, the mold cooling method according to the embodiment of this disclosure detects boiling of the refrigerant based on the pressure of the refrigerant flowing in the refrigerant channel, and controls the flow rate of the refrigerant if it is boiling. This makes it possible to provide a mold cooling method that can detect the boiling of the liquid refrigerant used to cool the mold at an early stage and control the cooling conditions of the mold. [Explanation of symbols]

[0036] 1. Mold Cooling System 11 molds 111, 112, 113 Refrigerant flow path 12 Refrigerant supply means 13. Pressure Sensor 14 Boiling determination means 15 Flow rate control means 16. Flow Measurement Methods

Claims

1. A mold cooling system that cools a mold by flowing a liquid coolant through a coolant channel formed in the mold, A pressure acquisition means for acquiring the pressure value of the refrigerant in the refrigerant flow path, The system includes a boiling determination means for determining whether or not the refrigerant boils based on the pressure value, If the pressure value exceeds the threshold, the boiling determination means determines that the refrigerant has boiled. Mold cooling system.

2. Furthermore, if the pressure value exceeds a first pressure threshold within a predetermined time, and falls below a second pressure threshold that is smaller than the first pressure threshold within the predetermined time, the boiling determination means determines that the refrigerant has boiled. The mold cooling system according to claim 1.

3. Furthermore, if the difference between the maximum pressure value and the minimum pressure value within a predetermined time exceeds a threshold, the boiling determination means determines that the refrigerant has boiled. The mold cooling system according to claim 1.

4. If the boiling determination means determines that the refrigerant has boiled, the system further includes a flow rate control means for controlling the flow rate of the refrigerant flowing through the refrigerant channel. A mold cooling system according to any one of claims 1 to 3.

5. A mold cooling method that cools a mold by flowing a liquid coolant through a coolant channel formed in the mold, A pressure acquisition step to acquire the pressure value of the refrigerant in the refrigerant flow path, A boiling determination step that determines whether or not the refrigerant boils based on the pressure value, If it is determined in the boiling determination step that the refrigerant has boiled, the system includes a flow rate control step that controls the flow rate of the refrigerant flowing through the refrigerant channel, In the boiling determination step, if the pressure value exceeds a threshold, it is determined that the refrigerant has boiled. Mold cooling method.

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