A control method of an aluminum water vacuum liquid taking device

Abstract

This invention relates to a control method for a vacuum extraction device for molten aluminum. The method includes, after opening a control valve and before the molten aluminum level in the transfer container reaches a limit level, at a preset time, if a second detected vacuum level detected by a vacuum degree detection mechanism reaches a second preset vacuum level, the vacuum pump is kept running at a first power. If the second detected vacuum level detected by the vacuum degree detection mechanism is lower than the second preset vacuum level, the vacuum pump is adjusted to run at a second power, which is greater than the first power. The second power is set such that after the vacuum pump runs at the second power for a first preset time, a third detected vacuum level detected by the vacuum degree detection mechanism exceeds the second detected vacuum level but is lower than the second preset vacuum level. This method can control the hydrogen content of molten aluminum with different hydrogen contents during the transfer process and maintain smooth flow of the molten aluminum.

Description

Technical Field

[0001] This invention relates to the field of aluminum die casting, and more specifically to a control method for a vacuum extraction device for molten aluminum. Background Technology

[0002] The aluminum die-casting industry requires a large number of intermediate molten aluminum transfer ladle to handle the round-trip transport of molten aluminum between the central melting furnace and the machine-side holding furnace. In the past, in order to safely transfer molten aluminum from the central melting furnace to the transfer ladle, it was necessary to install flow hole bricks at the bottom of the melting furnace and manually loosen the plugs to allow the molten aluminum to flow through the flow channel into the molten aluminum ladle. Therefore, it was necessary to lower the elevation of the transfer ladle and use a hydraulic lifting platform to move the transfer ladle up and down, or to raise the entire central melting furnace so that the elevation of the water discharge flow hole was higher than the ground, so that there was a certain height difference between the melting furnace flow hole and the top surface of the molten aluminum ladle, allowing the molten aluminum in the furnace to flow safely through the flow channel into the transfer ladle. These methods of transferring molten aluminum require frequent operation of the flow-through bricks and lifting and transferring the molten aluminum, which poses safety hazards. Furthermore, the high-temperature molten aluminum flows through an open flow channel and comes into contact with air, resulting in significant temperature loss and excessive oxidation of the molten aluminum, which affects its quality. In addition, because molten aluminum has a high solubility for hydrogen, it can also absorb hydrogen, increasing the hydrogen content of the molten aluminum and reducing the quality of the die-cast products.

[0003] An existing aluminum molten material transfer device, as described in Chinese patent application CN114368497A, connects a liquid extraction pipe and a vacuum pump via a metal hose to a sealing cap. The sealing cap can be raised and lowered to cover and seal the opening of a transfer ladle. The vacuum pump creates a vacuum by drawing air from the cavity inside the transfer ladle. One end of the liquid extraction pipe is connected to the transfer ladle, and the other end is connected to the aluminum melting furnace. Under vacuum, molten aluminum flows from the aluminum melting furnace through the liquid extraction pipe into the transfer ladle, achieving aluminum molten material transfer in a sealed environment. This reduces contact between air and molten aluminum, significantly reducing oxidation of the molten aluminum and effectively preventing the increase of hydrogen in the molten aluminum. This device can also remove some hydrogen from the molten aluminum using vacuum, reducing the hydrogen content and improving the quality of die-cast products. However, the hydrogen removal process needs further improvement to further stabilize the quality of the molten aluminum and the castings. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a control method for a vacuum aluminum liquid extraction device. This method can control the hydrogen content of aluminum liquids with different hydrogen contents during the transfer of aluminum liquid and maintain the smooth flow of aluminum liquid.

[0005] To achieve the objectives of this invention, a control method for a vacuum extraction device for molten aluminum is provided. The device includes a lifting device, a sealing cap, a vacuum pump, a pressure tank, a metal hose, and an extraction pipe. The lifting device drives the sealing cap and the extraction pipe to rise and fall simultaneously. The sealing cap seals the transfer bag by descending, and the first end of the extraction pipe passes through the sealing cap. The vacuum pump is located on one side of the lifting device and connected to the pressure tank. The pressure tank is connected to the metal hose via a control valve, and the metal hose passes through the sealing cap. A vacuum detection mechanism is provided inside the pressure tank. The control method includes: closing the control valve, starting the vacuum pump to operate at a first power to evacuate the pressure tank; and when the vacuum detection mechanism detects a first vacuum... When the vacuum level reaches the first preset vacuum value, the control valve is opened, creating a negative pressure inside the transfer pot and allowing molten aluminum to enter the transfer pot through the liquid extraction pipe. After opening the control valve and before the molten aluminum level in the transfer pot reaches the limit level, if the second detected vacuum level detected by the vacuum detection mechanism reaches the second preset vacuum value, the vacuum pump is kept running at the first power. If the second detected vacuum level detected by the vacuum detection mechanism is lower than the second preset vacuum value, the vacuum pump is adjusted to run at the second power, where the second power is greater than the first power, and the second power is set such that after the vacuum pump runs at the second power for a first preset time, the third detected vacuum level detected by the vacuum detection mechanism exceeds the second detected vacuum level but is lower than the second preset vacuum value.

[0006] In some embodiments of the present invention, if the second detected vacuum degree detected by the vacuum degree detection mechanism is lower than the second preset vacuum degree value, adjusting the vacuum pump to operate at the second power includes: if the difference between the second detected vacuum degree and the second preset vacuum degree value is within a first preset range, the second power adopts the first preset power value; if the difference between the second detected vacuum degree and the second preset vacuum degree value is within a second preset range, the second power adopts the second preset power value; if the value of the second preset range is greater than the value of the first preset range, the second preset power value is greater than the first preset power value.

[0007] In some embodiments of the present invention, the first preset power value and the second preset power value are determined by prior testing.

[0008] In some embodiments of the present invention, the difference between the second preset power value and the first preset power value is less than the difference between the first preset power value and the first power.

[0009] In some embodiments of the present invention, before closing the control valve, the method further includes: the lifting device driving the sealing cover to seal the transfer soup bag, and the second end of the liquid extraction pipe being inserted into the aluminum melting furnace.

[0010] In some embodiments of the present invention, the aluminum molten metal vacuum extraction device further includes a limit liquid level detection mechanism, the detection end of which is lower than the first end of the extraction pipe; when the limit liquid level detection mechanism detects that the aluminum molten metal in the transfer soup bag has reached the detection end of the limit liquid level detection mechanism, the control valve is closed and the vacuum pump is turned off.

[0011] In some embodiments of the present invention, the preset time is the time after the control valve is opened and the second preset time has elapsed.

[0012] In some embodiments of the present invention, the aluminum molten metal vacuum extraction device further includes an intermediate liquid level detection mechanism, the detection end of which is lower than the first end of the extraction pipe; the intermediate liquid level detection mechanism detects that the aluminum molten metal in the transfer soup bag reaches the detection end of the intermediate liquid level detection mechanism at a preset time.

[0013] In some embodiments of the present invention, the aluminum molten vacuum liquid extraction device further includes a flow detection mechanism, which is disposed in the liquid extraction pipe; the flow detection mechanism detects that the total flow rate of aluminum molten liquid flowing through the liquid extraction pipe reaches a preset flow rate as a preset time.

[0014] In some embodiments of the present invention, the time from opening the control valve to the preset time is a first time length, and the time from opening the control valve to the liquid level of the molten aluminum in the transfer soup bag reaching the limit liquid level is a second time length, and the difference between the first time length and the second time length is 1 / 2 to 1 / 4.

[0015] In some embodiments of the present invention, the outlet of the metal hose is higher than the first end of the liquid extraction pipe.

[0016] In some embodiments of the present invention, the first end of the liquid extraction pipe is open downwards, and the outlet of the metal hose is open upwards or to the side.

[0017] In some embodiments of the present invention, the liquid extraction pipe is an insulated pipe.

[0018] In some embodiments of the present invention, the first power, the first preset vacuum value, the second preset vacuum value, and the second power are adjusted according to the product requirements of subsequent die casting of molten aluminum.

[0019] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0020] The control method for the aluminum molten metal vacuum extraction device provided by this invention is based on an aluminum molten metal vacuum extraction device with a lifting sealing cover and negative pressure provided by a vacuum pump. It mainly utilizes the vacuum degree detected at the pressure storage tank at a specific preset moment during the aluminum molten metal vacuum extraction process as a parameter reflecting the hydrogen content of the aluminum molten metal in the melting furnace. Based on this vacuum degree, the power of the vacuum pump for subsequent operation is determined. This enables different vacuum extraction operations for aluminum molten metal with different hydrogen contents, thereby better removing hydrogen from the aluminum molten metal and maintaining the hydrogen content of the transferred aluminum molten metal within an appropriate range, thus stabilizing the quality of the aluminum molten metal and the castings. Simultaneously, controlling the power of the vacuum pump for subsequent operation within a suitable range maintains smooth flow of the aluminum molten metal and avoids excessively high vacuum levels that would cause the aluminum molten metal to flow too quickly and splash excessively onto the sealing cover or metal hose, leading to frequent cleaning and maintenance of the aluminum molten metal vacuum extraction device. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the aluminum molten metal vacuum extraction device used in the embodiments of the present invention.

[0022] Figure 2 This is a schematic diagram of the aluminum molten metal vacuum extraction device used in an embodiment of the present invention from another perspective.

[0023] Figure 3 yes Figure 2 A schematic diagram of the structure of section AA.

[0024] Figure 4 This is a structural diagram of the sealing cap, metal hose, and liquid extraction pipe of the aluminum molten metal vacuum liquid extraction device used in the embodiments of the present invention.

[0025] In the diagram, 1-lifting device, 2-sealing cover, 3-vacuum pump, 4-pressure storage tank, 5-metal hose, 6-liquid extraction pipe, 7-vacuum degree detection mechanism, 8-limit liquid level detection mechanism, 9-intermediate liquid level detection mechanism, 10-flow detection mechanism, 11-transfer soup bag.

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0027] like Figures 1 to 4 As shown, an embodiment of the present invention provides a control method for an aluminum molten vacuum extraction device. This control method is implemented based on the aluminum molten vacuum extraction device, which can be located between the aluminum melting furnace and the transfer pot 11. It is used to transfer the aluminum molten material from the aluminum melting furnace to the transfer pot 11. After the transfer pot 11 is separated from the aluminum molten vacuum extraction device, the aluminum molten material inside can be transported to the die casting machine.

[0028] The aluminum molten metal vacuum extraction device includes a lifting device 1, a sealing cover 2, a vacuum pump 3, a pressure tank 4, a metal hose 5, and an extraction pipe 6.

[0029] The lifting device 1 is used to drive the sealing cover 2 and the liquid extraction pipe 6 to rise and fall simultaneously. The lifting device 1 may include, for example, a vertical guide rail and a slider that can slide on the guide rail. The slider can be driven by a motor, cylinder or hydraulic cylinder to move or position on the guide rail. The guide rail can be fixed on a bracket. The sealing cover 2 and the liquid extraction pipe 6 can be located on the slider.

[0030] The sealing cap 2 is used to seal the transfer soup pack 11 by descending with the lifting device 1. When the sealing cap 2 rises with the lifting device 1, the sealing cap 2 can leave the transfer soup pack 11, which facilitates the extraction and transfer of liquid from the transfer soup pack 11.

[0031] The first end of the liquid extraction pipe 6 passes through the sealing cover 2, and the second end of the liquid extraction pipe 6 is used to extend into the molten aluminum in the aluminum melting furnace. The liquid extraction pipe 6 is used to extract molten aluminum.

[0032] The vacuum pump 3 is located on one side of the lifting device 1, for example, it can be mounted on a bracket together with the lifting device 1. The vacuum pump 3 is connected to the pressure tank 4, which can be used to store negative pressure, and together with the vacuum pump 3, provide negative pressure for the transfer soup bag 11, and can protect the vacuum pump 3 to prevent molten aluminum from entering the vacuum pump 3.

[0033] The pressure tank 4 is connected to the metal hose 5 via a control valve. The control valve can be located between the pressure tank 4 and the metal hose 5. When the control valve is open, the pressure tank 4 and the metal hose 5 are connected. When the control valve is closed, the pressure tank 4 and the metal hose 5 are disconnected.

[0034] A metal hose 5 passes through the sealing cap 2 and is used to extract gas from the transfer soup bag 11.

[0035] A vacuum degree detection mechanism 7 is installed inside the pressure tank 4. This mechanism is used to detect the vacuum degree within the pressure tank 4. Because the pressure tank 4 is connected to the transfer soup bag 11, the vacuum degree detected by the vacuum degree detection mechanism 7 is equivalent to the vacuum degree of the transfer soup bag 11. The placement of the vacuum degree detection mechanism 7 within the pressure tank 4 prevents it from directly contacting the molten aluminum, thus reducing the requirements for its high-temperature resistance and other performance characteristics.

[0036] Specifically, the control method in this embodiment includes:

[0037] Close the control valve to disconnect the pressure tank 4 from the transfer soup bag 11. Start the vacuum pump 3 at its first power to evacuate the pressure tank 4. The first power can be the default power of the vacuum pump 3.

[0038] When the vacuum detection mechanism 7 detects that the vacuum level inside the pressure tank 4, i.e., the first detected vacuum level, has reached the first preset vacuum level value, it opens the control valve, creating a negative pressure inside the transfer pot 11 and allowing molten aluminum to enter the transfer pot 11 through the liquid extraction pipe 6. The first preset vacuum level value can be a vacuum level value determined through pre-testing. Under this vacuum level value, after the pressure tank 4 is connected to the transfer pot 11, the molten aluminum can smoothly enter the transfer pot 11 through the liquid extraction pipe 6. The first preset vacuum level value can be, for example, -40kPa to -60kPa. When the control valve is closed, the vacuum detection mechanism 7 can detect the vacuum level inside the pressure tank 4 in real time or intermittently until the vacuum level, i.e., the first detected vacuum level, reaches the first preset vacuum level value, and then the control valve is opened.

[0039] After the control valve is opened and before the molten aluminum level in the transfer ladle 11 reaches the limit level, there is a preset time at which the vacuum detection mechanism 7 detects the vacuum level in the pressure tank 4, i.e., the second detection vacuum level. This preset time is a moment in the process of transferring molten aluminum from the aluminum melting furnace to the transfer ladle 11.

[0040] If the second vacuum level detected by the vacuum level detection mechanism 7 reaches the second preset vacuum level value, the vacuum pump 3 is kept running at the first power. Under the negative pressure inside the transfer pot 11, molten aluminum enters the transfer pot 11, and at the same time, at least some of the hydrogen in the molten aluminum is also drawn out by the negative pressure and discharged along the metal hose 5, the pressure tank 4, and the vacuum pump 3. The molten aluminum vacuum extraction device also has the function of discharging hydrogen. When the vacuum pump 3 is running at the first power, the vacuum level in the pressure tank 4 will decrease due to the extraction of hydrogen. The more hydrogen is extracted, the greater the decrease in vacuum level. Therefore, the second vacuum level detected by the vacuum level detection mechanism 7 can reflect the hydrogen content in the molten aluminum transferred from the aluminum melting furnace. The hydrogen content in the molten aluminum can be judged based on the second vacuum level, and the subsequent vacuum level can be further adjusted to adjust the hydrogen content in the molten aluminum. When the hydrogen content in the molten aluminum is high, more hydrogen is extracted, so that the hydrogen content in the molten aluminum used for die casting is kept within a relatively stable range, thereby making the quality of the die casting more stable. The second preset vacuum value is the vacuum level in the pressure tank 4 corresponding to the hydrogen content in the molten aluminum meeting the quality requirements of the die-cast aluminum parts, provided that the vacuum pump 3 operates at the first power. When the second detected vacuum level detected by the vacuum detection mechanism 7 reaches the second preset vacuum level at a preset time, it indicates that the hydrogen content in the molten aluminum meets the quality requirements of the die-cast aluminum parts. At this time, the vacuum pump 3 can continue to operate at the first power without adjusting the power of the positive vacuum pump 3, simplifying the operation control logic. The second detected vacuum level reaching the second preset vacuum level means that the second detected vacuum level is equal to or higher than the second preset vacuum level. Since the molten aluminum enters the transfer pot 11 and the hydrogen is drawn away, the second preset vacuum level can be lower than the first preset vacuum level. Here, the vacuum level and vacuum level value are compared in absolute terms.

[0041] If the second detected vacuum degree detected by the vacuum degree detection mechanism 7 is lower than the second preset vacuum degree value, the vacuum pump 3 is adjusted to operate at a second power, which is greater than the first power. When the second detected vacuum degree is lower than the second preset vacuum degree value, it indicates that there is a lot of hydrogen in the molten aluminum, and a large amount of hydrogen is being pumped out, causing the vacuum degree in the pressure tank 4 to drop below the second preset vacuum degree value. At this time, it is necessary to increase the operating power of the vacuum pump 3 so that the vacuum pump 3 can provide a greater negative pressure to pump out more hydrogen, reduce the hydrogen content in the molten aluminum, and keep the hydrogen content in the molten aluminum used for die casting within a stable range, thereby ensuring the stable quality of the die-cast parts.

[0042] The second power is set so that after the vacuum pump 3 operates at the second power for a first preset time, the third detected vacuum degree detected by the vacuum degree detection mechanism 7 exceeds the second detected vacuum degree but is lower than the second preset vacuum degree value. When the vacuum pump 3 operates at the second power, the vacuum degree inside the pressure tank 4 increases due to the increased operating power. However, the second power should not be too high. Excessive second power will cause a significant increase in the vacuum degree inside the transfer soup bag 11, resulting in excessively rapid aluminum flow. This can cause the aluminum, especially aluminum with a high hydrogen content and low density, to easily splash onto the sealing cap 2 or into the metal hose 5, requiring frequent cleaning and maintenance of the aluminum vacuum extraction device. Furthermore, it will reduce the average contact time between each unit of aluminum and the vacuum, leading to a poorer hydrogen removal effect. Therefore, limiting the second power to a state where the vacuum degree is higher than the second detected vacuum degree but does not reach the second preset vacuum degree value can both improve hydrogen removal efficiency and ensure smooth aluminum flow.

[0043] As can be seen from the above, the control method of this embodiment can control the hydrogen content of aluminum liquids with different hydrogen contents during the transfer of molten aluminum, and maintain the smooth flow of molten aluminum. It can be applied to scenarios where the hydrogen content of molten aluminum changes due to different types, batches, storage times or environmental conditions. By absorbing hydrogen during the transfer process, the hydrogen content of molten aluminum is kept stable within a certain range, which is beneficial to improving the quality of die-cast aluminum parts.

[0044] In some examples, if the second detected vacuum level detected by the vacuum level detection mechanism 7 is lower than the second preset vacuum level value, adjusting the vacuum pump 3 to operate at the second power includes: if the difference between the second detected vacuum level and the second preset vacuum level value is within a first preset range, the second power is the first preset power value; if the difference between the second detected vacuum level and the second preset vacuum level value is within a second preset range, the second power is the second preset power value; if the value of the second preset range is greater than the value of the first preset range, the second preset power value is greater than the first preset power value. In other words, the difference between the second detected vacuum level detected by the vacuum level detection mechanism 7 and the second preset vacuum level value is calculated, and the interval corresponding to this difference is determined. The specific value of the second power is then determined based on the interval, avoiding frequent changes in the second power and simplifying the operation.

[0045] In some examples, the first and second preset power values ​​are determined through pre-testing. This can be done before the aluminum molten metal vacuum extraction device leaves the factory or after it is applied to the production workshop. Actual testing can determine which power level ensures that after the vacuum pump 3 operates at the first or second preset power value for a first preset time, the third detected vacuum level detected by the vacuum degree detection mechanism 7 exceeds the second detected vacuum level but is lower than the second preset vacuum level. Alternatively, extensive data collection can be performed in advance to determine different first and second preset power values ​​for variations in parameters such as the volume of different transfer soup bags 11. In actual application, the first and second preset power values ​​are determined by looking up tables based on the parameters in the production workshop.

[0046] In some examples, the difference between the second preset power value and the first preset power value is smaller than the difference between the first preset power value and the first power. When the difference between the second detected vacuum degree and the second preset vacuum degree value increases, the increase in the second power is smaller relative to the increase in the second detected vacuum degree and the second preset vacuum degree value. This is because when the hydrogen content in the molten aluminum is higher, the density of the molten aluminum decreases, making it easier for the molten aluminum to splash, and the contact time between each unit of molten aluminum and the vacuum needs to be extended. Therefore, the increase in the second preset power value relative to the first preset power value is set to be smaller than the increase in the first preset power value relative to the first power.

[0047] In some examples, before closing the control valve, the process includes: the lifting device 1 driving the sealing cover 2 to seal the transfer pot 11, thus achieving a seal on the transfer pot 11. The transfer pot 11 also has a first cover body of similar size to the sealing cover 2. When the sealing cover 2 leaves the transfer pot 11, the first cover body closes the opening of the transfer pot 11 for engaging with the sealing cover 2, facilitating the transport of the transfer pot 11. The transfer pot 11 also has a gating gate sealed by a second cover body, which is used to pour molten aluminum at the die-casting station. The second end of the molten aluminum extraction pipe 6 is inserted into the aluminum melting furnace, for example, into the side or side pool of the aluminum melting furnace, for drawing molten aluminum.

[0048] In some examples, the aluminum molten vacuum extraction device also includes a limit liquid level detection mechanism 8. In the vertical direction, the detection end of the limit liquid level detection mechanism 8 is lower than the first end of the extraction pipe 6. When the limit liquid level detection mechanism 8 detects that the aluminum molten in the transfer pot 11 has reached the detection end of the limit liquid level detection mechanism 8, the control valve is closed, the vacuum pump 3 is turned off, and the aluminum molten filling in the transfer pot 11 is completed.

[0049] In some alternative examples, the preset time can be the time after the control valve is opened and the operation has run for a second preset time. That is, the time starts from when the control valve is opened, and the preset time is reached when the second preset time is reached. Determining the preset time by using time simplifies the control logic.

[0050] In some alternative examples, for determining the preset time, the aluminum molten metal vacuum extraction device also includes an intermediate liquid level detection mechanism 9. In the vertical direction, the detection end of the intermediate liquid level detection mechanism 9 is lower than the first end of the extraction pipe 6 and also lower than the detection end of the limit liquid level detection mechanism 8. The preset time is defined as when the intermediate liquid level detection mechanism 9 detects that the aluminum molten metal in the transfer pot 11 has reached its detection end; that is, when the aluminum molten metal in the transfer pot 11 reaches the middle position where the detection end of the intermediate liquid level detection mechanism 9 is located, this is determined as the preset time. Using this method to determine the preset time and test the vacuum degree at that time provides a more accurate assessment of the hydrogen content in the aluminum molten metal. The intermediate liquid level detection mechanism 9 needs to be inserted into the middle position inside the transfer pot 11, and the intermediate liquid level detection mechanism 9 needs to have a considerable length, requiring a longer stroke when the sealing cover 3 moves up and down.

[0051] In some alternative examples, for determining the preset time, the aluminum molten metal vacuum extraction device also includes a flow detection mechanism 10, which is located in the extraction pipe 6. The preset time is defined as when the total flow rate of aluminum molten metal flowing through the extraction pipe 6 reaches the preset flow rate. Using this method to determine the preset time and test the vacuum degree at that time makes the assessment of the hydrogen content in the aluminum molten metal more accurate.

[0052] In some examples, the time from opening the control valve to a preset time is the first time length, and the time from opening the control valve to the liquid level of the molten aluminum in the transfer pot 11 reaching the limit liquid level is the second time length. The difference between the first time length and the second time length is 1 / 2 to 1 / 4. That is, by controlling the change in vacuum degree in the first short period after the molten aluminum is stably injected during the molten aluminum filling process, the vacuum degree of hydrogen extraction in the subsequent long period of time can be controlled, which is beneficial to the overall control of the hydrogen content of the molten aluminum.

[0053] In some examples, the outlet of the metal hose 5 is higher than the first end of the liquid extraction pipe 6, reducing the possibility of molten aluminum output from the first end of the liquid extraction pipe 6 splashing into the metal hose 5.

[0054] In some examples, the first end of the liquid extraction pipe 6 is open downwards, allowing molten aluminum to be poured directly downwards. The outlet of the metal hose 5 is open upwards or to the side; for example, the metal hose 5 can be bent so that the outlet is open upwards or to the side, further reducing the possibility of molten aluminum output from the first end of the liquid extraction pipe 6 splashing into the metal hose 5.

[0055] In some examples, the liquid extraction pipe 6 is an insulated pipe, and the molten aluminum inside the liquid extraction pipe 6 is kept at a high temperature to prevent the molten aluminum from solidifying inside the liquid extraction pipe 6. The sealing cap 3 and the transfer soup bag 11 can also be made of insulated materials.

[0056] In some examples, the first power, first preset vacuum value, second preset vacuum value, and second power are adjusted according to the product requirements of subsequent die casting of molten aluminum. For example, the hydrogen content requirements of subsequent die casting products can be determined through pre-testing of the parameter values ​​of the first power, first preset vacuum value, second preset vacuum value, and second power. When applied in the actual production workshop, the hydrogen content requirements of the actual die casting products can be determined, and the first power, first preset vacuum value, second preset vacuum value, and second power can be determined by looking up tables, etc., which can both ensure the quality of die casting products and improve production efficiency.

[0057] Finally, it should be emphasized that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control method for a vacuum extraction device for molten aluminum, the device comprising a lifting device, a sealing cover, a vacuum pump, a pressure tank, a metal hose, and an extraction pipe; the lifting device is used to drive the sealing cover and the extraction pipe to rise and fall simultaneously, the sealing cover is used to seal the transfer bag by falling, and the first end of the extraction pipe passes through the sealing cover; the vacuum pump is located on one side of the lifting device, the vacuum pump is connected to the pressure tank, the pressure tank is connected to the metal hose through a control valve, the metal hose passes through the sealing cover, and a vacuum degree detection mechanism is provided inside the pressure tank; characterized in that... The control method includes: Close the control valve, start the vacuum pump to run at the first power, and evacuate the pressure tank; when the first detected vacuum degree detected by the vacuum degree detection mechanism reaches the first preset vacuum degree value, open the control valve to create a negative pressure in the transfer soup bag and allow the molten aluminum to enter the transfer soup bag through the liquid extraction pipe. After the control valve is opened and before the molten aluminum level in the transfer pot reaches the limit level, molten aluminum enters the transfer pot. At a preset time after the control valve is opened and before the molten aluminum level in the transfer pot reaches the limit level, if the second detected vacuum level detected by the vacuum detection mechanism reaches a second preset vacuum level value, the vacuum pump is kept running at a first power. The second detected vacuum level reflects the hydrogen content in the molten aluminum transferred from the aluminum melting furnace to the transfer pot. If the second detected vacuum level detected by the vacuum detection mechanism is lower than the second preset vacuum level value, the vacuum pump is adjusted to run at a second power to draw in more hydrogen. The second power is greater than the first power, and the second power is set such that after the vacuum pump runs at the second power for a first preset time, the third detected vacuum level detected by the vacuum detection mechanism exceeds the second detected vacuum level but is lower than the second preset vacuum level value, thus removing hydrogen and reducing molten aluminum splashing onto the sealing cap or into the metal hose. Adjust the first power, the first preset vacuum value, the second preset vacuum value, and the second power according to the product requirements of subsequent die casting of molten aluminum.

2. The control method for the aluminum molten metal vacuum extraction device according to claim 1, characterized in that... If the second detected vacuum degree detected by the vacuum degree detection mechanism is lower than the second preset vacuum degree value, adjusting the vacuum pump to operate at the second power includes: If the difference between the second detected vacuum degree and the second preset vacuum degree value is within a first preset range, the second power is the first preset power value; If the difference between the second detected vacuum degree and the second preset vacuum degree value is within a second preset range, the second power is the second preset power value. The value of the second preset range is greater than the value of the first preset range, and the second preset power value is greater than the first preset power value.

3. The control method for the aluminum molten metal vacuum extraction device according to claim 2, characterized in that... The first preset power value and the second preset power value are determined by prior testing; The difference between the second preset power value and the first preset power value is less than the difference between the first preset power value and the first power.

4. The control method for a vacuum extraction device for molten aluminum according to claim 1, characterized in that... Before closing the control valve, the method further includes: the lifting device driving the sealing cover to seal the transfer soup bag, and the second end of the liquid extraction pipe being inserted into the aluminum melting furnace; The aluminum molten metal vacuum extraction device also includes a limit liquid level detection mechanism, the detection end of which is lower than the first end of the extraction pipe; when the limit liquid level detection mechanism detects that the aluminum molten metal in the transfer soup bag has reached the detection end of the limit liquid level detection mechanism, the control valve is closed and the vacuum pump is turned off.

5. A control method for a vacuum extraction device for molten aluminum according to any one of claims 1 to 4, characterized in that... The preset time is the time after the control valve is opened and the second preset time has elapsed.

6. A control method for a vacuum extraction device for molten aluminum according to any one of claims 1 to 4, characterized in that... The aluminum molten metal vacuum extraction device also includes an intermediate liquid level detection mechanism, the detection end of which is lower than the first end of the extraction pipe; the intermediate liquid level detection mechanism detects that the aluminum molten metal in the transfer soup bag reaches the detection end of the intermediate liquid level detection mechanism at a preset time.

7. A control method for a vacuum extraction device for molten aluminum according to any one of claims 1 to 4, characterized in that... The aluminum molten metal vacuum extraction device also includes a flow detection mechanism, which is located in the extraction pipe; the flow detection mechanism detects when the total flow rate of aluminum molten metal flowing through the extraction pipe reaches a preset flow rate as a preset time.

8. A control method for a vacuum extraction device for molten aluminum according to any one of claims 1 to 4, characterized in that... The time from opening the control valve to the preset time is the first time length, and the time from opening the control valve to the aluminum liquid level in the transfer soup bag reaching the limit liquid level is the second time length. By controlling the change in vacuum degree in the first short period after the stable injection of aluminum liquid during the aluminum liquid filling process, the vacuum degree of hydrogen extraction in the subsequent long period of time is controlled.

9. A control method for a vacuum extraction device for molten aluminum according to any one of claims 1 to 4, characterized in that... The outlet of the metal hose is higher than the first end of the liquid extraction pipe; The first end of the liquid extraction pipe is open downwards, and the outlet of the metal hose is open upwards or to the side; the liquid extraction pipe is an insulated pipe.

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