Mold cooling system and mold cooling method

Abstract

The invention provides a mold cooling system and a mold cooling method capable of early detecting boiling of a liquid refrigerant for cooling a mold and controlling cooling conditions of the mold. A mold cooling system according to the present invention cools a mold by causing a liquid refrigerant to flow through a refrigerant flow path formed in the mold, the mold cooling system being provided with: a pressure acquisition means for acquiring the pressure value of the refrigerant in the refrigerant flow path; and a boiling determination means for determining the presence or absence of boiling of the refrigerant on the basis of the pressure value, the boiling determination means determining that the refrigerant is boiling when the pressure value exceeds a threshold value.

Description

Technical Field

[0001] This invention relates to a mold cooling system and a mold cooling method. Background Technology

[0002] Patent document 1 discloses a temperature management method for casting molds, which determines whether the cooling water is boiling based on the mold temperature near the part of the cooling water flow path of the casting mold where boiling of the cooling water may occur and the discharge rate of the cooling water on the outlet side of the cooling water channel.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-108434 Summary of the Invention

[0004] However, in the temperature management method for casting molds disclosed in Patent Document 1, it is difficult to measure the mold temperature with high precision. Therefore, it is difficult to determine the boiling of cooling water based on the mold temperature with high precision and speed.

[0005] The present invention was made in view of the above-mentioned actual situation, and provides a mold cooling system and mold cooling method that can detect the boiling of liquid refrigerant in the cooling mold at an early stage and control the cooling conditions of the mold.

[0006] The mold cooling system according to one aspect of the present invention cools the mold by causing liquid refrigerant to flow in a refrigerant flow path formed in the mold, the mold cooling system comprising:

[0007] The pressure acquisition mechanism acquires the pressure value of the refrigerant in the refrigerant flow path; and the boiling determination mechanism determines whether the refrigerant is boiling based on the pressure value. If the pressure value exceeds a threshold, the boiling determination mechanism determines that the refrigerant is boiling.

[0008] One aspect of the present invention relates to a mold cooling method that cools a mold by allowing liquid refrigerant to flow in a refrigerant flow path formed in the mold. The mold cooling method includes: a pressure acquisition step for acquiring a pressure value of the refrigerant in the refrigerant flow path; a boiling determination step for determining whether the refrigerant is boiling based on the pressure value; and a flow control step for controlling the flow rate of the refrigerant flowing in the refrigerant flow path if the refrigerant is determined to be boiling in the boiling determination step, wherein the refrigerant is determined to be boiling if the pressure value exceeds a threshold value in the boiling determination step.

[0009] Invention Effects

[0010] According to the present invention, a mold cooling system and a mold cooling method are provided that can detect the boiling of liquid refrigerant in the cooling mold at an early stage and control the cooling conditions of the mold. Attached Figure Description

[0011] Figure 1 This is a block diagram of a mold cooling system according to an embodiment of the present invention.

[0012] Figure 2 This is a graph showing the relationship between the elapsed time of the mold according to the embodiments of the present invention and the temperature and pressure inside the refrigerant flow path.

[0013] Figure 3 This is a flowchart illustrating a mold cooling method according to an embodiment of the present invention. Detailed Implementation

[0014] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments. Furthermore, for clarity, the following description and drawings have been appropriately simplified.

[0015] <Mold Cooling System>

[0016] Figure 1 This is a block diagram of a mold cooling system according to an embodiment of the present invention.

[0017] The mold cooling system 1 includes a mold 11, a refrigerant supply mechanism 12, a pressure sensor 13, a boiling determination mechanism 14, a flow control mechanism 15, and a flow measurement mechanism 16. Furthermore, the mold 11 has refrigerant flow paths 111 to 113. Additionally, the pressure sensor 13 is a pressure acquisition mechanism.

[0018] Mold 11 is, for example, a die-casting mold, having a cavity (not shown) into which molten metal is poured. The poured molten metal is cooled and solidified, and removed from mold 11 as a casting. The material of mold 11 is, for example, ferrous metals such as carbon steel, cast steel, cast iron, or hot work tool steel. Furthermore, the size of mold 11 is appropriately determined according to the size of the target casting. The material of the metal poured into mold 11 is, for example, an alloy such as aluminum alloy, zinc alloy, or magnesium alloy.

[0019] Refrigerant flow paths 111-113 are configured to pass through the interior of the mold 11 and connect to the refrigerant supply mechanism 12. Liquid refrigerant received from the refrigerant supply mechanism 12 flows through refrigerant flow paths 111-113, cooling the mold 11. The refrigerant flow paths 111-113 are made of metal pipes such as steel, stainless steel, or copper.

[0020] in addition, Figure 1The mold cooling system 1 shown has three refrigerant flow paths 111, 112, and 113. However, the number of refrigerant flow paths can be two or less or four or more, depending on the target cooling conditions or the location of the cavity. Furthermore, the refrigerant flowing through the refrigerant flow paths 111 to 113 can be any liquid, such as water. Rust inhibitors such as nitrite-based, chromate-based, molybdate-based, or zinc salt-based agents can be added to the water to function as a coolant.

[0021] The refrigerant supply mechanism 12 is connected to the refrigerant flow paths 111-113 and the flow control mechanism 15. The refrigerant supply mechanism 12 supplies refrigerant to the refrigerant flow paths 111-113. The refrigerant supply mechanism 12 is, for example, composed of a refrigerant tank and a mechanical pump. Alternatively, multiple refrigerant supply mechanisms 12 may be provided in the mold cooling system 1, each connected to one of the refrigerant flow paths 111-113. Furthermore, the refrigerant supply mechanism 12 may also have a refrigerant circulation function that recovers the supplied refrigerant and resupplys it to the refrigerant flow paths 111-113. In addition, during refrigerant circulation, the refrigerant supply mechanism 12 may also have an impurity treatment function that removes impurities generated in the refrigerant during circulation.

[0022] Pressure sensor 13 is connected to refrigerant flow paths 111-113 and boiling determination mechanism 14. Pressure sensor 13 is disposed within refrigerant flow paths 111-113 and measures the pressure value within these paths. 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. Furthermore, pressure sensor 13 can also be a pressure control valve with a mechanism that opens when a constant pressure is detected. In this case, pressure sensor 13 and boiling determination mechanism 14 can also be configured as a single pressure control valve.

[0023] Furthermore, multiple pressure sensors 13 can be configured within the refrigerant flow paths 111-113, or one or more can be configured in each of the refrigerant flow paths 111, 112, and 113. Preferably, the pressure sensors 13 are positioned within the refrigerant flow paths 111-113 near the molten metal where the refrigerant easily causes a temperature rise. By configuring the pressure sensors 13 at locations where the refrigerant easily causes a temperature rise, refrigerant boiling can be detected at an earlier stage.

[0024] The boiling determination mechanism 14 is connected to the pressure sensor 13 and the flow control mechanism 15. The boiling determination mechanism 14 receives refrigerant pressure information from the pressure sensor 13 and determines whether the refrigerant is boiling based on the received pressure information. The boiling determination mechanism 14 may be configured as, for example, a central processing unit (CPU), a microprocessor (MPU), a working memory, and a non-volatile storage device storing control programs. Furthermore, as described above, the boiling determination mechanism 14 may also be configured as a pressure control valve integrated with the pressure sensor 13.

[0025] Figure 2 This is a graph showing the relationship between the elapsed time of the mold according to the embodiments of the present invention 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 111-113, and the dashed line represents the change in refrigerant pressure over time in the refrigerant flow paths 111-113.

[0026] exist Figure 2 In (A), the temperature within the refrigerant flow path shows an almost constant value T1 (e.g., approximately 100°C in the case of water as the refrigerant), but the pressure within the refrigerant flow path rises sharply. The boiling determination mechanism 14, for example, in... Figure 2 In (A), the pressure of the refrigerant was detected to exceed the threshold PA, and it was determined that the refrigerant was boiling.

[0027] Furthermore, in Figure 2 In (B), the temperature inside the refrigerant flow path is Figure 2 After (A), the value T1 remains almost constant, but the pressure within the refrigerant flow path fluctuates rapidly within a short period. The boiling determination mechanism 14, for example, in... Figure 2 Within the time range tB of (B), if the pressure in the refrigerant flow path exceeds the first pressure threshold PB1 and is less than the second pressure threshold PB2 which is smaller than PB1, it is determined that the refrigerant is boiling. Furthermore, the boiling determination mechanism 14 can also receive the maximum pressure value Pmax and the minimum pressure value Pmin within the time range tB, detect that the pressure difference Pmax-Pmin exceeds the threshold, and determine that the refrigerant is boiling.

[0028] Furthermore, in embodiments of the present invention, the pressure thresholds PA, PB1, and PB2, the pressure difference Pmax-Pmin, and the time range tB are appropriately determined as values ​​capable of detecting refrigerant boiling. Moreover, artificial intelligence (AI) can learn time-varying data of temperature and pressure within the refrigerant flow path, and determine the pressure thresholds PA, PB1, and PB2, and the time range tB based on the learned data. New boiling determination conditions can also be derived based on this learned data.

[0029] The flow control mechanism 15 is connected to the refrigerant supply mechanism 12 and the boiling determination mechanism 14. Based on the determination result of the boiling determination mechanism 14, the flow control mechanism 15 controls the refrigerant supply from the refrigerant supply mechanism 12. The flow control mechanism 15 may be composed of, for example, a CPU, an MPU, a working memory, and a non-volatile storage device storing a control program.

[0030] Furthermore, if the boiling detection mechanism 14 detects that the refrigerant is boiling, the flow control mechanism 15, for example, increases the flow rate of the refrigerant supplied by the refrigerant supply mechanism 12. This suppresses the boiling of the refrigerant flowing through the refrigerant flow paths 111-113. Assuming that in the case of refrigerant boiling, the mold 11 exchanges heat with the gaseous refrigerant, the heat transfer rate from the mold to the refrigerant decreases significantly compared to the case of heat exchange with the liquid refrigerant. Therefore, the cooling efficiency of the mold 11 using refrigerant decreases significantly. In other words, by suppressing the boiling of the refrigerant, the decrease in the cooling efficiency of the mold 11 can be suppressed.

[0031] Furthermore, the flow control mechanism 15 can perform different flow control on 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 is boiling, the following control can be performed: only the flow rate of refrigerant flowing through refrigerant flow path 111 is increased, without changing the flow rate of refrigerant flowing through refrigerant flow paths 112 and 113. Also, if it is determined that only the refrigerant in refrigerant flow path 111 is boiling, the following control can be performed: the flow rate of refrigerant flowing through refrigerant flow path 111 is increased, while the flow rate of refrigerant flowing through refrigerant flow paths 112 and 113 is decreased, so that the overall refrigerant flow rate remains unchanged. By performing different flow control on each of the refrigerant flow paths 111 to 113, the temperature of the mold 11 can be made more uniform, thereby improving the quality of the casting.

[0032] The flow measuring mechanism 16 is disposed within the refrigerant flow paths 111 to 113. The flow measuring mechanism 16 measures the flow rate of the refrigerant flowing through the refrigerant flow paths 111 to 113. Alternatively, if the refrigerant supply mechanism 12 has a refrigerant circulation function, the flow measuring mechanism 16 may also be disposed within the refrigerant circulation path. The flow measuring mechanism 16 may be, for example, an ultrasonic flow meter, an electromagnetic flow meter, a float-type flow meter, or a differential pressure flow meter.

[0033] As explained above, the mold cooling system according to the embodiments of the present invention measures the pressure of the refrigerant flowing through the refrigerant flow path and detects the boiling of the refrigerant based on the measured pressure value. Therefore, a mold cooling system capable of detecting the boiling of liquid refrigerant in the mold at an early stage and controlling the cooling conditions of the mold can be provided.

[0034] <Mold Cooling Methods>

[0035] Next, refer to Figure 3 The mold cooling method according to the embodiments of the present invention will be described. Figure 3 This is a flowchart illustrating a mold cooling method according to an embodiment of the present invention.

[0036] First, pressure sensor 13 acquires the pressure value of the refrigerant within the refrigerant flow paths 111-113 (step S1). Here, pressure sensor 13 can acquire the refrigerant pressure value continuously or at regular intervals. Furthermore, for example, at times when the refrigerant is considered likely to boil, such as after molten metal is injected into mold 11, the frequency of acquiring the refrigerant pressure value can be increased compared to other times. Conversely, at times when the refrigerant is considered unlikely to boil, such as after the casting is removed from mold 11, the frequency of acquiring the refrigerant pressure value can be decreased compared to other times.

[0037] Next, the boiling determination mechanism 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 step S3, which is the next boiling determination step. 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 flow paths 111 to 113.

[0038] If the determination in step S2 is "No", the boiling determination mechanism 14 determines whether the change in refrigerant pressure within a specified time range exceeds a threshold (step S3). The determination in step S3 is, for example, in... Figure 2Within the time range tB of (B), if the pressure in the refrigerant flow path exceeds the first pressure threshold PB1 but is less than the second pressure threshold PB2 (which is smaller than PB1), it is determined that the refrigerant is boiling. Furthermore, it can also receive the maximum pressure value Pmax and the minimum pressure value Pmin within the time range tB, and if the pressure difference Pmax-Pmin exceeds the threshold, it is determined that the refrigerant is boiling.

[0039] In step S3, if the change in refrigerant pressure does not exceed a threshold within a specified time range ("No" in step S3), it is determined whether to end the cooling of mold 11 (step S4). The determination of cooling end is based, for example, on the progress of the casting process. If the cooling of mold 11 ends ("Yes" in step S4), the process ends; if the cooling of mold 11 continues ("No" in step S4), the process returns to step S1, and the pressure of refrigerant in refrigerant flow paths 111-113 is obtained again.

[0040] On the other hand, if the change in refrigerant pressure exceeds a threshold within a specified time range ("Yes" in step S3), step S5 is initiated to control the flow rate of refrigerant flowing through refrigerant flow paths 111 to 113.

[0041] If the determination in step S2 or step S3 is "yes", the flow control mechanism 15 controls the flow rate of the refrigerant flowing in the refrigerant flow path 111-113 (step S5). After controlling the refrigerant flow rate in step S5, the process returns to step S1 and obtains the pressure value of the refrigerant in the refrigerant flow path 111-113 again.

[0042] As explained above, the mold cooling method according to the embodiments of the present invention detects the boiling of the refrigerant based on the pressure of the refrigerant flowing through the refrigerant flow path, and controls the flow rate of the refrigerant when it boils. Therefore, a mold cooling method is provided that can detect the boiling of the liquid refrigerant cooling the mold at an early stage and control the cooling conditions of the mold.

[0043] Symbol Explanation

[0044] 1-Mold cooling system, 11-Mold, 111, 112, 113-Refrigerant flow path, 12-Refrigerant supply mechanism, 13-Pressure sensor, 14-Boiling determination mechanism, 15-Flow control mechanism, 16-Flow measurement mechanism.

Claims

1. A mold cooling system that cools the mold by causing liquid refrigerant to flow in a refrigerant flow path formed in the mold, characterized in that, have: A pressure sensing mechanism acquires the pressure value of the refrigerant within the refrigerant flow path; and The boiling determination mechanism determines whether the refrigerant is boiling based on the pressure value. If the pressure value exceeds the threshold, the boiling determination mechanism determines that the refrigerant is boiling.

2. The mold cooling system according to claim 1, characterized in that, If the pressure value exceeds a first pressure threshold within a specified time and is less than a second pressure threshold smaller than the first pressure threshold within the specified time, the boiling determination mechanism determines that the refrigerant is boiling.

3. The mold cooling system according to claim 1, characterized in that, If the difference between the maximum pressure value and the minimum pressure value within a specified time exceeds a threshold, the boiling determination mechanism determines that the refrigerant is boiling.

4. The mold cooling system according to any one of claims 1 to 3, characterized in that, It also has: A flow control mechanism that controls the flow rate of the refrigerant flowing in the refrigerant path when the boiling determination mechanism determines that the refrigerant is boiling.

5. A mold cooling method, wherein the mold is cooled by causing a liquid refrigerant to flow in a refrigerant flow path formed in the mold, characterized in that, include: The pressure acquisition step acquires the pressure value of the refrigerant within the refrigerant flow path. The boiling determination step determines whether the refrigerant is boiling based on the pressure value. and The flow control step, in which, if the boiling determination step determines that the refrigerant is boiling, controls the flow rate of the refrigerant flowing in the refrigerant flow path. In the boiling determination step, if the pressure value exceeds the threshold, it is determined that the refrigerant is boiling.

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