Metal casting system, molten metal holding furnace and molten metal quantitative supply device

Abstract

The invention aims to overcome the defects of material waste and poor product quality caused by inaccurate quantitative supply of molten metal due to the adoption of a method and a structure for supplying compressed gas into a furnace body and quantitatively outputting the molten metal by virtue of the pressure of the compressed gas in the prior art. The invention provides a metal casting system, a molten metal holding furnace and a molten metal quantitative supply device, the molten metal quantitative supply device comprises a quantitative piston, a quantitative piston cylinder, a quantitative pressurization control system and a quantitative and pressurization driving device, the quantitative piston is positioned in a piston cylinder body of the quantitative piston cylinder; the molten metal holding furnace comprises a molten metal holding device, a molten metal quantitative supply device and a molten metal liquid lifting device, the metal casting system, the molten metal holding furnace and the molten metal quantitative supply device adopting the structure can obtain accurate quantitative supply, reduce unstable product quality caused by unstable supply quantity, and improve product quality. And raw materials can be effectively saved.

Description

Technical Field

[0001] The invention belongs to the technical field of molten metal transfer equipment, and in particular relates to a metal casting system, a molten metal holding furnace and a molten metal quantitative supply device. Background Art

[0002] A holding furnace is a container for storing molten metal and maintaining a certain temperature or appropriately raising the temperature of the molten metal. When using the molten metal in the furnace, it is necessary to take the molten metal out of the furnace in the required amount and send it to the device that needs the molten metal. At present, the quantitative transfer of molten metal mostly adopts a pressure quantitative supply device to quantitatively transport the molten metal liquid. The StrikoWestofen pneumatic quantitative furnace, which is widely used in the market, also adopts the pressure quantitative supply method and structure. For example, the Chinese utility model patent with the patent publication number CN219283942U is named as a gas pressure quantitative insulation furnace, which includes a furnace box body 1, a liquid discharge mechanism 2 is fixedly arranged on one side of the upper end surface of the furnace box body 1, a liquid inlet mechanism 3 is fixedly connected to the side of the upper end surface of the furnace box body 1 away from the liquid discharge mechanism 2, a gas pressure control mechanism 4 is fixedly arranged on one side of the furnace box body 1, a host control system 5 is fixedly arranged on the front of the furnace box body 1, and an insulation box 6 is fixedly arranged in the furnace box body 1. The insulation box 6 can maintain the liquid temperature, and the insulation box 6 is fixedly provided with an electric heating device 7. The design can ensure the process temperature of the aluminum liquid. When working, the molten aluminum liquid is added from the liquid inlet mechanism 3 through the water transfer bag, and the electric heating device 7 is used in the insulation furnace to perform quantitative insulation furnace aluminum liquid heating and insulation functions; through the liquid discharge mechanism The liquid discharge mechanism 2, the host control system 5, and the air pressure control mechanism 4 jointly control the liquid discharge. When the die-casting machine completes a die-casting operation and transmits a signal to the holding furnace control system, the host control system 5 controls the liquid discharge mechanism 2 to open, and the air pressure control mechanism 4 injects compressed gas into the holding furnace. The quantitative aluminum liquid supply is realized through simulation calculation by the host control system 5. The above device and method are used to quantitatively supply the furnace liquid. Since the compressed gas is injected into the holding furnace, the supply amount of the molten metal liquid is controlled by the size of the gas pressure and the supply pressure time. The pressure of the compressed gas is released when it is supplied to the furnace body. Therefore, its pressure itself is unstable, resulting in inaccurate control of the liquid level by the gas pressure, inaccurate supply of the molten metal liquid, and more waste is generated in the process. Moreover, a large amount of compressed gas is consumed in this process, and more energy is consumed. On the other hand, the compressed gas will oxidize the molten metal liquid on the surface, thereby reducing the quality of the molten metal liquid and affecting the quality of the finished product. In particular, when the holding furnace is used in the metal casting industry, such as high-pressure, low-pressure or medium-pressure metal casting, the holding furnace is often used to keep the molten metal warm and store it, and then the molten metal is pressed into the cavity of the casting mold to complete the casting.

[0003] In addition, the molten metal insulation furnace of the prior art adopts a two-chamber structure, and the furnace body is divided into a left chamber furnace (pressurized chamber) and a right chamber furnace (insulation chamber). The right chamber furnace is connected to the atmosphere, and a movable furnace cover is arranged on the top, and a conventionally heated hot dip pipe is arranged at the bottom of the right chamber furnace. A furnace door and a furnace door cover inclined at 45 degrees are arranged at the right end of the right chamber furnace for feeding and insulation. The left chamber furnace is a closed chamber, and a fixed sealed furnace cover is arranged above the left chamber furnace. An immersion tube heater, a thermocouple, and a liquid level gauge are arranged on the top of the furnace cover. They are used to measure the temperature and liquid level of the aluminum liquid in the left chamber furnace. When the aluminum liquid temperature in the left chamber furnace is lower than the set pouring stability, the heater is turned on to heat up the aluminum liquid in the left chamber furnace. An inclined pouring cup sprue sleeve is arranged at the left end of the left chamber furnace, one end of which is immersed in the aluminum liquid and the other end is open. By pressurizing the left chamber, the aluminum liquid flows out through the open end of the pouring cup sprue sleeve. A scanning electrode is set above the opening end of the pouring cup sprue sleeve, which is a standard for determining the pouring state. The left and right chambers are connected by a valve. When the valve is opened, the liquid in the right chamber enters the left chamber. When the liquid levels of the left and right chambers are level, the valve is closed to maintain the air tightness of the left chamber. In addition, a gas control device is set on the upper part of the left chamber, which includes an air charging valve group, a pressure sensor, and an air release valve. Since the gas control device and the scanning electrode used in conjunction with the gas control device are set on the furnace body, a constant positive pressure can be set in the furnace body through the gas control device and the scanning electrode, and the volume change after the pressure change in the furnace body can be calculated by the electronic control device to achieve high-precision quantitative delivery of aluminum liquid. With the above structure, when the pressure is increased, the molten metal liquid is conveyed out from the pouring cup and the sprue sleeve. When the molten metal is quantitatively conveyed and the pressure is released, the pressure in the furnace drops rapidly, and the molten metal conveyed through the infusion pipe and the molten metal in the pouring cup and the sprue sleeve will quickly flow back into the left chamber furnace, filling up the molten metal and debris settled at the bottom of the furnace, thereby causing the molten metal to churn, and the debris settled at the bottom of the furnace is churned up, reducing the quality of the molten metal, thereby reducing the quality of the product. Summary of the invention

[0004] The purpose of the present invention is to provide a metal casting system, a molten metal holding furnace and a molten metal quantitative supply device in response to the shortcomings of the prior art that compressed gas is supplied into the furnace body and molten metal is quantitatively output by the pressure of the compressed gas, so that the quantitative supply of molten metal is inaccurate, resulting in material waste and poor product quality.

[0005] The technical solution of the present invention to solve the technical problem is as follows: A molten metal quantitative supply device, comprising a quantitative piston, a quantitative piston cylinder, a quantitative pressurization control system and a quantitative and pressurization drive device, wherein the quantitative piston is located in a piston cylinder body of the quantitative piston cylinder and is slidably connected with the inner surface clearance of the piston cylinder body cavity, the inner cavity of the piston cylinder body is located below the quantitative piston and forms a pressurization chamber, the pressurization chamber is used to accommodate molten metal, the output end of the quantitative and pressurization drive device is located in the piston cylinder body, the upper surface of the quantitative piston is fixedly connected to the output end of the quantitative and pressurization drive device, the quantitative and pressurization control system is connected with the quantitative and pressurization drive device by electrical signals, the quantitative and pressurization control system controls the quantitative and pressurization drive device to drive the quantitative piston to move a set stroke in the piston cylinder body, thereby quantitatively and pressurizingly outputting molten metal from the pressurization chamber, and the pressurization chamber receives the input molten metal, the quantitative and pressurization drive device is a servo drive device, and the quantitative pressurization control system is a servo control system; The servo drive device is one of a servo hydraulic system, a servo electric cylinder, and a servo motor; or the pressurizing chamber is used to communicate with the molten metal lifting device and the holding chamber arranged in the holding chamber furnace body, the holding chamber is used to contain the molten metal after refining and keep it warm, the holding chamber provides molten metal to the pressurizing chamber, and the molten metal quantitatively and pressurized output from the pressurizing chamber is output to the molten metal lifting device; The quantitative piston and the inner cavity of the quantitative piston cylinder are both made of high temperature resistant materials, and the high temperature resistant materials are high temperature resistant ceramics; and / or the gap between the quantitative piston and the inner cavity of the piston cylinder is movably connected with liquid sealing.

[0006] A molten metal holding furnace, comprising a molten metal holding device, a molten metal quantitative supply device, and a molten metal lifting device, wherein the molten metal holding device comprises a holding chamber furnace body, a holding furnace plug rod, a holding furnace plug rod driving device, a holding chamber heating device, and a holding chamber temperature detection device, wherein a holding chamber liquid outlet is arranged at the bottom of the holding chamber furnace body and is connected to the inner cavity of the holding chamber, and a holding chamber plug rod passage opening is arranged at the top of the holding chamber furnace body for the holding furnace plug rod to pass through and is movably connected to the holding furnace plug rod in a sealed manner, the holding furnace plug rod passage opening is colinear with the center line of the holding chamber liquid outlet, one end of the holding furnace plug rod is located in the holding chamber, and the other end is fixedly connected to the output end of the holding furnace plug rod driving device, and the holding chamber plug rod can close the holding chamber liquid outlet or leave the holding chamber liquid outlet under the drive of the holding furnace plug rod driving device, and the holding chamber is used to contain molten metal and keep it warm; The molten metal quantitative supply device adopts the structure of the above-mentioned molten metal quantitative supply device; The molten metal lifting device comprises a lifting furnace, in which a lifting chamber is arranged, through which the molten metal enters into the mold cavity of the casting machine. The liquid raising chamber, the pressurizing chamber and the holding chamber are connected to each other through the chamber connecting channel below, the liquid raising chamber and the pressurizing chamber are freely connected, and the chamber connecting channel is connected to the holding chamber through the liquid outlet of the holding chamber; When the molten metal quantitative supply device supplies the molten metal quantitatively and under pressure, the plug rod of the holding furnace enters the liquid outlet of the holding chamber and closes the liquid outlet of the holding chamber; The liquid lifting chamber is cylindrical in shape as a whole, and comprises a liquid lifting channel and a contraction portion of the liquid lifting channel. A liquid lifting channel outlet channel is provided at the liquid outlet end of the contraction portion of the liquid lifting channel, and the contraction portion of the liquid lifting channel is connected with the liquid outlet end of the liquid lifting channel through its small diameter end; The holding chamber, the pressurizing chamber and the liquid raising chamber are arranged side by side, the liquid raising chamber is cylindrical as a whole, and the liquid outlet end of the liquid raising channel opens upward; The quantitative piston is driven by the quantitative pressurizing driving device to move down a set distance from the origin position of the quantitative piston, to pressurize the molten metal in the pressurizing chamber and implement quantitative supply, and the quantitative pressurizing control system controls the stroke of the quantitative piston in one of the following ways: when the quantitative and pressurizing are completed, the quantitative pressurizing driving device does not act, and the quantitative piston is kept in the original position after the filling and pressurizing. When the next filling is required, the piston continues to move down a set distance at the original position after the filling and pressurizing, and the downward movement is repeated multiple times until the piston needs to return to the origin position, the insulation furnace plug rod is opened, and the molten metal is filled from the holding chamber to the pressurizing chamber and the liquid lifting chamber, and the molten metal is suspended in the liquid lifting chamber. When the next pressurizing and filling is required, the piston is in the quantitative and pressurizing driving device. The piston is driven to move downward again by a set distance until the molten metal needs to be added to the lifting chamber and the pressure chamber after multiple times of filling and pressurization. After the quantitative and pressurization driving device drives the piston back to the original position, the insulation furnace plug rod is opened again, and the molten metal in the holding chamber flows into the pressure chamber, the lifting chamber and the cavity connecting channel again to reach a preset height. The insulation furnace plug rod closes the liquid outlet of the holding chamber again, and the quantitative pressurization driving device drives the piston downward again in sections according to the set stroke until the molten metal needs to be filled into the pressure chamber and the lifting chamber again. The quantitative and pressurization are repeated in this way. When the quantitative piston returns to the original position, the liquid level of the molten metal in the holding chamber must be higher than or equal to the height of the lower end surface of the quantitative piston when the quantitative piston is at the origin. Alternatively, each time quantitative supply and pressurized filling are completed, the piston returns to the original position, and then moves downward from the original position to perform quantitative supply and pressurized filling. At the same time, the plug rod of the insulation furnace makes corresponding movements, so that when the piston returns, the holding chamber and the pressurized chamber are connected, so that the molten metal enters the pressurized chamber and the liquid raising chamber, reaches the bottom of the piston and contacts the piston, and when the quantitative piston returns to the original position, the liquid level of the molten metal in the holding chamber must be higher than or equal to the height of the lower end surface of the quantitative piston when the quantitative piston is at the original position; Alternatively, the quantitative pressurizing drive device drives the quantitative piston to move down a set distance from the origin position of the quantitative piston, quantitatively delivers and pressurizes the molten metal, and the molten metal enters the mold cavity from the liquid outlet channel of the liquid lifting channel. After the filling is completed, the quantitative piston position remains unchanged, and the quantitative and pressurizing drive device and the quantitative piston continue to provide pressure for the molten metal liquid. When the molten metal in the mold cavity solidifies, the quantitative pressurizing drive device drives the quantitative piston to make a partial return stroke according to a preset displacement, so that the quantitative piston returns to below the origin position, so that the molten metal is suspended in the liquid lifting chamber, waiting for the next quantitative delivery, and repeating the quantitative and pressurizing drive multiple times. Pressurization, each return stroke is a partial return stroke, keeping the molten metal suspended in the liquid lifting chamber, until the pressurization chamber needs to be supplemented with molten metal, the quantitative pressurization drive device drives the quantitative piston back to the original position, and the insulation furnace plug rod makes a corresponding action, so that when the piston returns to the original position or thereafter, the chamber and the pressurization chamber are connected, so that the molten metal enters the pressurization chamber and the liquid lifting chamber, and then the quantitative and pressurization are repeated many times, each return stroke is a partial return stroke, keeping the molten metal suspended in the liquid lifting chamber, until the pressurization chamber needs to be supplemented with molten metal again, the quantitative pressurization drive device drives the quantitative piston back to the original position, and the cycle action is repeated; When the liquid level of the molten metal in the holding chamber is equal to or lower than the height of the lower end surface of the metering piston when the metering piston is at the original position, the molten metal is added to the holding chamber.

[0007] A metal casting system comprises a casting machine and a molten metal holding furnace, wherein the molten metal holding furnace adopts the molten metal holding furnace of the above structure; The casting machine is one of a low-pressure casting machine, a high-pressure casting machine, a differential pressure casting machine or an extrusion casting machine, and is connected to the mold cavity of the casting machine through the liquid lifting chamber. The advantages and beneficial effects of the present invention are: In the molten metal quantitative supply device of the structure of the present invention, the volume of molten metal pushed by the quantitative piston when it is displaced is the supply amount of the molten metal, and this supply amount is positively correlated only with the displacement amount of the quantitative piston. Therefore, the accuracy of the quantitative supply amount can be controlled by controlling the displacement accuracy of the quantitative piston. Therefore, the molten metal quantitative supply device of the present invention is used in conjunction with a servo drive device to obtain accurate quantitative supply, reduce unstable product quality caused by unstable supply amount, and effectively save raw materials.

[0008] The molten metal holding furnace using the structure of the embodiment of the present invention has the following advantages: 1. Precise quantitative supply; 2. When the metal liquid level falls back, it will not cause the molten metal to churn; 3. The three-chamber structure of holding chamber, pressurizing chamber and liquid raising chamber is adopted, so that the aluminum liquid can be evenly heated in different chambers, reducing temperature differences, and the temperature uniformity of the molten metal is good, thereby ensuring the stability of the quality of the aluminum liquid. 4. Improve production efficiency: Since the holding chamber is only used to hold the metal liquid, when quantitative and pressurized supply is carried out, the holding chamber is closed. Therefore, the metal liquid has sufficient heating and insulation time in the holding chamber, and the aluminum liquid can be continuously supplied, reducing production interruptions caused by waiting for the aluminum liquid to heat up, thereby improving the overall production efficiency. 5. Reduce oxidation and slag inclusion: The holding chamber is closed when no metal liquid is added, providing a relatively stable environment, reducing the contact between the aluminum liquid and the air, reducing the generation of oxidation and slag inclusion, and improving the purity of the aluminum liquid. 6. Easy to control and adjust: Each chamber can independently control the temperature and flow, which is convenient for flexible adjustment according to production needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the overall structure of an embodiment of a metal casting system of the present invention; Figure 2 for Figure 1 A is an enlarged view.

[0010] DESCRIPTION OF SYMBOLS 100-molten metal holding device; 101-insulating furnace stopper rod; 102-insulating furnace stopper rod driving device; 103-holding chamber; 104-holding chamber furnace body; 105, holding chamber liquid outlet; 200-molten metal quantitative supply device; 201-quantity and pressurization drive device; 202-quantity piston; 203-quantity piston cylinder; 204-piston cylinder body cavity; 205-pressurization chamber; 300-molten metal lifting device; 301-liquid lifting channel; 302-liquid lifting channel contraction portion; 303-liquid lifting channel outlet channel; 400-heating device; 500-casting machine; 501-upper mold; 502-lower mold; 503-cavity; 504-pouring gate; 505-pouring cup and sprue sleeve; 506-mold diverter cone; 600-chamber communication channel; 700-Molten metal. DETAILED DESCRIPTION

[0011] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0012] like Figure 1As shown, the molten metal holding furnace of the embodiment of the present invention includes a molten metal holding device 100, a molten metal pressurizing unit 200 and a molten metal lifting device 300. The molten metal holding device is used to hold the molten metal 700 and convey the molten metal 700 to the molten metal pressurizing unit. The molten metal pressurizing unit is used to pressurize the molten metal and quantitatively press the molten metal to the molten metal lifting device. The molten metal lifting device conveys the molten metal to the mold cavity of the casting machine to complete the filling of the molten metal. The molten metal holding device 100, the molten metal pressurizing unit 200 and the molten metal lifting device 300 are all provided with a heating device and a temperature detection device to detect the temperature of the molten metal and heat it.

[0013] The molten metal holding device 100 includes a holding chamber furnace body 104, an insulation furnace plug rod 101 and an insulation furnace plug rod driving device 102. A holding chamber 103 is arranged in the holding chamber furnace body. The holding chamber contains molten metal such as aluminum liquid after refining and qualification. A holding chamber liquid outlet 105 is arranged at the bottom of the holding chamber furnace body and communicates with the inner cavity of the holding chamber. A insulation furnace plug rod passage opening for the insulation furnace plug rod to pass through and seal and cooperate with the insulation furnace plug rod is arranged at the top of the holding chamber furnace body. The insulation furnace plug rod passage opening is colinear with the center line of the holding chamber liquid outlet 105. One end of the insulation furnace plug rod is located in the holding chamber, and the other end is fixedly connected to the output end of the insulation furnace plug rod driving device. The insulation furnace plug rod can close the holding chamber liquid outlet or leave the holding chamber liquid outlet under the drive of the insulation furnace plug rod driving device. A holding chamber heating device and a temperature detection device are arranged inside or outside the holding chamber so that the holding chamber can reach and maintain the set temperature.

[0014] The molten metal quantitative supply device 200 includes a quantitative and pressurizing drive device 201, a quantitative piston 202, a quantitative piston cylinder 203 and a quantitative pressurizing control system (not shown in the figure). For the convenience of description, the inner cavity of the quantitative piston cylinder 203 is called the piston cylinder inner cavity 204. The quantitative piston is located in the piston cylinder inner cavity. The part of the quantitative piston cylinder inner cavity located below the quantitative piston constitutes a pressurizing chamber 205. The pressurizing chamber is used for quantitative pressurizing the molten metal. The output end of the quantitative and pressurizing drive device 201 is located in the piston cylinder inner cavity and fixedly connected to the upper surface of the quantitative piston. The quantitative piston and the quantitative piston cylinder inner cavity are in a clearance fit sliding connection. The quantitative and pressurizing drive device 201 can adopt a servo drive device, such as a servo motor, a servo electric cylinder, a servo hydraulic cylinder, etc. The servo drive device drives the piston to reciprocate in the quantitative piston cylinder inner cavity. Since the stroke of the servo drive device can be pre-set in the control system, and the servo drive output has high precision, it can accurately control the position of the quantitative quantitative piston. The position controlled has high precision and good stability. Therefore, the stroke error of each piston movement is small. When a servo drive device is used as a quantitative pressurizing drive device, the quantitative and pressurizing control system adopts a servo control system. The quantitative pressurizing control system is connected to the quantitative pressurizing drive device by electrical signals. When quantitative supply is required, the quantitative pressurizing control system controls the quantitative pressurizing drive device to move a set distance to complete the quantitative supply of molten metal liquid.

[0015] The molten metal lifting device 300 includes a lifting furnace, in which a lifting chamber is provided. The lifting chamber is used for the lifting of molten metals such as aluminum liquid, and the molten metal enters the casting machine mold cavity through the lifting chamber. The lifting chamber is preferably a cylindrical structure, including a lifting channel 301 and a lifting channel contraction part 302, and a lifting channel outlet channel 303 is provided at the liquid outlet end of the lifting channel contraction part; the lifting channel contraction part is connected to the liquid outlet end of the lifting channel through its small diameter end, and a chamber connecting channel 600 is provided below the holding chamber, the pressurizing chamber and the lifting chamber. The lower ends of the holding chamber, the pressurizing chamber and the lifting chamber are connected through the chamber connecting channel, and the lifting chamber and the pressurizing chamber share a heating device to maintain the temperature of the molten metal. The caliber of the lifting channel outlet channel 303 is consistent with the caliber shape and size of the connection between it and the lifting channel contraction part, and is a uniform channel. By adopting the above structure and setting a contraction part of the liquid lifting channel, the cross-sectional area of ​​the liquid lifting channel and the chamber connecting channel can be kept at a relatively large ratio. This is conducive to setting an appropriate amount of molten metal liquid in the liquid lifting chamber and the chamber connecting channel, so that the molten metal liquid can be kept at a certain temperature, and the temperature of the molten metal can be kept uniform, and it can be prevented that the amount of molten metal in the chamber connecting channel and the liquid lifting chamber is too small and the temperature drops too quickly, resulting in uneven temperature. The liquid lifting chamber is cylindrical as a whole. In the structure of the present invention, the three chambers of the holding chamber, the pressurizing chamber and the liquid lifting chamber are arranged side by side, and the chamber connecting channel is located below the three. The three are connected to each other through the lower end. The casting machine and the holding furnace of the present invention constitute a metal casting system. The holding furnace of the present invention can be used in combination with a low-pressure casting machine or a high-pressure casting machine. When used in combination with a high-pressure casting machine, the liquid outlet channel of the liquid riser channel is connected to the injection cavity of the high-pressure casting machine. It can also be used in a differential pressure casting machine or an extrusion casting machine. When used in an extrusion casting machine, the liquid outlet channel of the liquid riser channel is connected to the pouring port of the mold cavity. When the metal casting system of the present invention is working, firstly, the refined aluminum liquid and other molten metals are placed in the holding chamber, and the heating device can be arranged in the holding chamber to heat the inner cavity of the holding chamber. A radiation heating device can also be arranged outside the holding chamber to heat the holding chamber so that the temperature of the molten metal in the holding chamber reaches and maintains the set temperature. The aluminum liquid and other molten metals can be heated and kept warm by bottom heating or radiation heating. When the molten metal needs to enter the pressurizing chamber, the insulation furnace plug rod driving device drives the insulation furnace plug rod to move up, and the holding chamber outlet 105 is opened. The aluminum liquid and other molten metals can flow into the pressurizing chamber, the liquid rising chamber and the chamber connecting channel so that the holding chamber, the pressurizing chamber and the liquid rising chamber all have the aluminum liquid and other molten metals that have been refined and qualified. When the molten metal fills the pressurizing chamber, the liquid rising chamber and the chamber connecting channel, the insulation furnace plug rod moves down to close the holding chamber outlet. The heating device 400 in the chamber connecting channel 600 heats and keeps the molten metal warm. When the casting machine needs to be filled with molten metal, the insulation furnace plug rod is kept in a closed state. When filling is required, the quantitative pressure driving device drives the quantitative piston to move down a set distance from the origin position of the quantitative piston, pressurizes the molten metal in the pressurizing chamber and implements quantitative supply. During the whole process, since the cross-sectional area of ​​the inner cavity of the piston cylinder is fixed, the volume of the liquid lifting chamber and the chamber connecting channel is also unchanged. Therefore, by accurately controlling the displacement of the piston, the amount of molten metal filled into the cavity can be accurately controlled, so that the volume of the quantitatively supplied molten metal is accurate. Since both the servo drive and the cam drive have the characteristics of high displacement accuracy, the amount of molten metal supplied each time is relatively accurate. Moreover, when pressurizing, the servo drive has good speed and acceleration stability and good pressure uniformity, so the filling speed is uniform.After the pressure filling is completed, the actions of the piston and the insulation furnace stopper rod are as follows: the first one is that when the quantitative and pressurization are completed, the quantitative pressurization drive device does not move, and the piston is kept in the original position after the filling and pressurization. When the next filling is required, the piston continues to move down a set distance from the original position after the filling and pressurization, and repeats the downward movement several times until the piston needs to return to the original position, open the insulation furnace stopper rod, and fill the molten metal from the holding chamber to the pressurization chamber and the liquid lifting chamber, and make the molten metal suspended in the liquid lifting chamber. When the next pressurization filling is required, the piston is in the quantitative and pressurization drive The piston is driven by the device to move downward again until the molten metal needs to be added to the lifting chamber and the pressure chamber after multiple filling and pressurization. After the quantitative and pressurization driving device drives the piston back to the original position, the insulation furnace plug rod is opened again, and the molten metal in the holding chamber flows into the pressure chamber, the lifting chamber and the cavity connecting channel again to reach a preset height. The insulation furnace plug rod closes the liquid outlet of the holding chamber again, and the quantitative pressurization driving device drives the piston downward in sections according to the set stroke again until the pressure chamber and the lifting chamber need to be filled with molten metal again, and the quantitative and pressurization are repeated in this way. The situations where the quantitative piston needs to return to the original position include but are not limited to when the amount of molten metal is insufficient and to ensure that the molten metal in the pressurized chamber maintains a set temperature. The advantage of this method is that quantitative supply and pressurized filling are completed at the same time. After each quantitative supply and pressurized filling is completed, the piston remains in place and waits for the next quantitative supply and pressurized filling. In this way, the operation efficiency of the entire system is high and the control system is simple and reliable. In actual production, batch production is generally carried out. For the same batch of castings, the amount of molten metal that needs to be supplied is certain. Therefore, the position of the piston can be controlled with higher accuracy and the quantitative supply amount is more accurate, which can effectively save molten metal raw materials.Moreover, there is no need to return the piston every time, so that the molten metal liquid level can remain stable, which is more conducive to the stability of liquid flow during filling and to the improvement of product quality. In this case, when the metering piston returns to the origin position, the liquid level of the molten metal in the holding chamber must be higher than or equal to the height of the lower end surface of the metering piston when the metering piston is at the origin; in the second case, after each quantitative supply and pressurized filling, the piston returns to the origin position, and then moves downward from the origin position to perform quantitative supply and pressurized filling. This requires that the insulation furnace plug rod makes corresponding movements so that when the piston returns, the holding chamber and the pressurized chamber are connected, so that the molten metal enters the pressurized chamber and the liquid lifting chamber, reaches the bottom of the piston and contacts the piston. In the above case, It adopts the working principle of a communicating vessel. It is necessary to keep the liquid level in the chamber always higher than or equal to the height of the lower end surface when the piston is at the origin position, so as to ensure that the molten metal reaches the bottom of the piston and contacts its lower end surface after each return stroke of the piston. There are two measures to maintain the liquid level in the holding chamber. One is to set the holding chamber at a high position, and rely on the geographical location to keep the liquid level in the holding chamber higher than or equal to the height of the lower end surface when the piston is at the origin position. The other is to monitor or calculate the height of the liquid level in the holding chamber. When the liquid level is lower than the height of the lower end surface when the piston is at the origin position, add molten metal into the holding chamber. This can be achieved by an automatic device, or by manual monitoring and manual addition of molten metal, which will not be elaborated. Another measure is to add inert gas above the liquid level in the holding chamber, and add a certain gas pressure to the liquid level in the holding chamber, so that when molten metal is added to the pressurizing chamber, even if the liquid level in the holding chamber is lower than the height of the lower end surface of the piston when the piston is at the origin position, the molten metal can reach below the lower end surface of the piston at the origin position and contact it. When this measure is adopted, since there is inert gas in the holding chamber and it has a certain pressure, the structure of the equipment becomes slightly complicated. The type of piston return stroke is selected in combination with the type of casting machine. In the holding furnace with the structure of the present invention, since the liquid outlet of the holding chamber is closed during decompression, the molten metal after decompression will not flow back into the holding chamber, and will not cause impact on the molten metal in the holding chamber, and there will be no reflux of molten metal, and the molten metal in the holding chamber will not be caused to churn. Since the piston has a certain speed when it returns, the pressure is released evenly. Therefore, the molten metal in the lifting chamber, the chamber connecting channel and the pressurized chamber withdraws at a uniform speed, the liquid level is stable, and will not cause the liquid in the holding furnace to surge. Therefore, the purity of the molten metal filled into the cavity can be guaranteed, and the phenomenon of metal impurities caused by the churning of the molten metal being filled into the cavity can be prevented.

[0016] The present invention uses the example of quantitatively providing aluminum liquid into the cavity of a low-pressure metal casting machine to illustrate the working process. The basic structure of the low-pressure casting machine adopts the structure of the prior art, including an upper mold and a lower mold. When the upper mold and the lower mold are closed, the internal cavity thereof constitutes a cavity. A pouring port 504 is provided at the bottom of the lower mold, and a pouring cup sprue sleeve 505 is provided below the pouring port. The pouring cup sprue sleeve is sealed and connected to the liquid outlet channel of the liquid lifting channel. A mold diverter cone 506 is provided on the upper mold at a position opposite to the pouring cup sprue sleeve. When molten metal needs to be filled into the casting machine cavity, the quantitative pressurizing drive device drives the quantitative piston to move downward a set distance from the origin position of the quantitative piston, so as to quantitatively convey and pressurize the molten metal. The molten metal passes through the pouring cup sprue sleeve from the liquid outlet channel of the liquid lifting channel and then It enters the mold cavity through the pouring gate. The area between the pouring cup, pouring sleeve and the pouring gate constitutes the nozzle. The molten metal ejected from the nozzle is guided and diverted by the mold diverter cone and enters the mold cavity. The mold diverter cone guides the molten metal liquid from the die-casting machine nozzle to various parts of the mold cavity, ensuring that the metal liquid can fill the cavity evenly and quickly, reducing defects in the filling process, and at the same time plays a diversion role to divide the metal liquid into multiple streams, so that it is more evenly distributed in the cavity, thereby improving the quality and performance of the casting. The diversion of the metal liquid through the mold diverter cone can reduce turbulence, effectively reduce the degree of disorder in the flow of the metal liquid, and reduce the generation of bubbles and inclusions. After the filling is completed, the quantitative piston position remains stationary, and the quantitative and pressurizing drive device and the piston continue to provide pressure for the molten metal liquid. When the molten metal in the mold cavity solidifies, the quantitative and pressurizing drive device drives the quantitative piston to make a partial return stroke according to the pre-set displacement, that is, it does not reset to the original position of the quantitative piston during the return stroke but returns to below the original position, so that the molten metal is suspended and waits for the next quantitative delivery. The quantitative and pressurizing are repeated many times, and each return stroke is a partial return stroke to keep the molten metal suspended in the liquid lifting chamber. Until the molten metal needs to be supplemented to the pressurizing chamber, the quantitative and pressurizing drive device drives the quantitative piston back to the original position, and the insulation furnace plug rod makes a corresponding action, so that when the quantitative piston returns or after the return stroke, the chamber and the pressurizing chamber are connected, so that the molten metal enters the pressurizing chamber and the liquid lifting chamber, filling the pressurizing chamber, and repeating the above quantitative and pressurizing process.

[0017] In the present invention, in order to ensure the high temperature resistance and service life of the quantitative piston cylinder and the quantitative piston, it is preferred that the quantitative piston and the inner cavity of the quantitative piston cylinder are made of high temperature resistant materials such as high temperature resistant ceramic materials, such as silicon nitride ceramics, and there is a clearance fit active connection between the inner cavity wall of the piston cylinder body, preferably a clearance fit molten metal liquid self-sealing active connection. Since the molten metal liquid itself has a certain surface tension, when the clearance between the piston cylinder body and the piston is fitted, the molten metal liquid can form a liquid seal between the two. Therefore, the molten metal liquid below the piston is prevented from entering the inner cavity of the piston cylinder above the piston or the amount of metal liquid entering the inner cavity of the piston cylinder is very small, and at the same time, smooth movement between the two can be ensured.

[0018] The molten metal holding furnace of the structure of the present invention has the following advantages due to the three-chamber structure of the holding chamber, the pressurizing chamber and the liquid rising chamber: 1. Good temperature uniformity: Through reasonable zoning design, the aluminum liquid can be evenly heated in different chambers, reducing the temperature difference, thereby ensuring the stability of the quality of the aluminum liquid. 2. Improve production efficiency: Since the holding chamber is only used to accommodate the metal liquid, when quantitative and pressurized supply is performed, the holding chamber is closed. Therefore, the metal liquid has sufficient heating and insulation time in the holding chamber, and the aluminum liquid can be continuously supplied, reducing the production interruption caused by waiting for the aluminum liquid to heat up, thereby improving the overall production efficiency. 3. Reduce oxidation and slag inclusion: The holding chamber is closed when no metal liquid is added, providing a relatively stable environment, reducing the contact between the aluminum liquid and the air, reducing the generation of oxidation and slag inclusion, and improving the purity of the aluminum liquid. 4. Convenient control and adjustment: Each chamber can independently control the temperature and flow, which is convenient for flexible adjustment according to production needs.

Claims

1. A molten metal quantitative supply device, characterized in that: It includes a quantitative piston, a quantitative piston cylinder, a quantitative pressurization control system and a quantitative and pressurization driving device. The quantitative piston is located in the piston cylinder body of the quantitative piston cylinder and is slidably connected with the inner surface of the piston cylinder body through a clearance fit. The inner cavity of the piston cylinder body is located below the quantitative piston, forming a pressurization chamber. The pressurization chamber is used to accommodate molten metal. The output end of the quantitative and pressurization driving device is located in the piston cylinder body. The upper surface of the quantitative piston is fixedly connected to the output end of the quantitative and pressurization driving device. The quantitative and pressurization control system is connected with the quantitative and pressurization driving device by electrical signals. The quantitative and pressurization control system controls the quantitative and pressurization driving device to drive the quantitative piston to move a set stroke in the piston cylinder body, thereby quantitatively and pressurizing the output of the molten metal from the pressurization chamber. The pressurization chamber receives the input molten metal. The quantitative and pressurization driving device is a servo driving device, and the quantitative pressurization control system is a servo control system.

2. A molten metal quantitative supply device according to claim 1, characterized in that: The servo drive device is one of a servo hydraulic system, a servo electric cylinder, and a servo motor; or the pressurizing chamber is used to communicate with the molten metal lifting device and the holding chamber arranged in the holding chamber furnace body, the holding chamber is used to contain the molten metal after refining and keep it warm, the holding chamber provides molten metal to the pressurizing chamber, and the molten metal output in a quantitative and pressurized manner from the pressurizing chamber is output to the molten metal lifting device.

3. A molten metal quantitative supply device according to claim 1, characterized in that: The quantitative piston and the inner cavity of the quantitative piston cylinder are both made of high temperature resistant materials, and the high temperature resistant materials are high temperature resistant ceramics; and / or the gap between the quantitative piston and the inner cavity of the piston cylinder is movably connected with liquid sealing.

4. A molten metal holding furnace, characterized in that: It comprises a molten metal holding device, a molten metal quantitative supply device, and a molten metal lifting device. The molten metal holding device comprises a holding chamber furnace body, an insulation furnace plug rod, an insulation furnace plug rod driving device, a holding chamber heating device, and a holding chamber temperature detection device. A holding chamber liquid outlet is arranged at the bottom of the holding chamber furnace body and is connected to the inner cavity of the holding chamber. A insulation furnace plug rod passage opening for the insulation furnace plug rod to pass through and is movably connected to the insulation furnace plug rod in a sealed manner is arranged at the top of the holding chamber furnace body. The insulation furnace plug rod passage opening is colinear with the center line of the holding chamber liquid outlet. One end of the insulation furnace plug rod is located in the holding chamber, and the other end is fixedly connected to the output end of the insulation furnace plug rod driving device. The insulation furnace plug rod can close the holding chamber liquid outlet or leave the holding chamber liquid outlet under the drive of the insulation furnace plug rod driving device. The holding chamber is used to contain molten metal and keep it warm. The molten metal quantitative supply device adopts the structure of the molten metal quantitative supply device according to any one of claims 1 to 3; The molten metal lifting device comprises a lifting furnace, in which a lifting chamber is arranged, through which the molten metal enters into the mold cavity of the casting machine. The liquid raising chamber, the pressurizing chamber and the holding chamber are connected to each other through the chamber connecting channel below, the liquid raising chamber and the pressurizing chamber are freely connected, and the chamber connecting channel is connected to the holding chamber through the liquid outlet of the holding chamber; When the molten metal quantitative supply device supplies the molten metal quantitatively and under pressure, the plug rod of the heat-insulating furnace enters into the liquid outlet of the holding chamber and closes the liquid outlet of the holding chamber.

5. A molten metal holding furnace as claimed in claim 4, characterized in that: The lifting chamber is cylindrical as a whole, including a lifting channel and a lifting channel contraction part. A lifting channel outlet channel is provided at the liquid outlet end of the lifting channel contraction part, and the lifting channel contraction part is connected with the lifting channel outlet end through its small diameter end.

6. A molten metal holding furnace as claimed in claim 4, characterized in that: The holding chamber, the pressurizing chamber and the liquid raising chamber are arranged side by side, the liquid raising chamber is cylindrical as a whole, and the liquid outlet end of the liquid raising channel opens upward.

7. A molten metal holding furnace as claimed in claim 1, characterized in that: The quantitative piston is driven by the quantitative pressurizing driving device to move down a set distance from the origin position of the quantitative piston, to pressurize the molten metal in the pressurizing chamber and implement quantitative supply, and the quantitative pressurizing control system controls the stroke of the quantitative piston in one of the following ways: when the quantitative and pressurizing are completed, the quantitative pressurizing driving device does not act, and the quantitative piston is kept in the original position after the filling and pressurizing. When the next filling is required, the piston continues to move down a set distance at the original position after the filling and pressurizing, and the downward movement is repeated multiple times until the piston needs to return to the origin position, the insulation furnace plug rod is opened, and the molten metal is filled from the holding chamber to the pressurizing chamber and the liquid lifting chamber, and the molten metal is suspended in the liquid lifting chamber. When the next pressurizing and filling is required, the piston is in the quantitative and pressurizing driving device. The piston is driven to move downward again by a set distance until the molten metal needs to be added to the lifting chamber and the pressure chamber after multiple times of filling and pressurization. After the quantitative and pressurization driving device drives the piston back to the original position, the insulation furnace plug rod is opened again, and the molten metal in the holding chamber flows into the pressure chamber, the lifting chamber and the cavity connecting channel again to reach a preset height. The insulation furnace plug rod closes the liquid outlet of the holding chamber again, and the quantitative pressurization driving device drives the piston downward again in sections according to the set stroke until the molten metal needs to be filled into the pressure chamber and the lifting chamber again. The quantitative and pressurization are repeated in this way. When the quantitative piston returns to the original position, the liquid level of the molten metal in the holding chamber must be higher than or equal to the height of the lower end surface of the quantitative piston when the quantitative piston is at the origin. Alternatively, each time quantitative supply and pressurized filling are completed, the piston returns to the original position, and then moves downward from the original position to perform quantitative supply and pressurized filling. At the same time, the plug rod of the insulation furnace makes corresponding movements, so that when the piston returns, the holding chamber and the pressurized chamber are connected, so that the molten metal enters the pressurized chamber and the liquid raising chamber, reaches the bottom of the piston and contacts the piston, and when the quantitative piston returns to the original position, the liquid level of the molten metal in the holding chamber must be higher than or equal to the height of the lower end surface of the quantitative piston when the quantitative piston is at the original position; Alternatively, the quantitative pressurizing drive device drives the quantitative piston to move down a set distance from the origin position of the quantitative piston, quantitatively delivers and pressurizes the molten metal, and the molten metal enters the mold cavity from the liquid outlet channel of the liquid lifting channel. After the filling is completed, the quantitative piston position remains unchanged, and the quantitative and pressurizing drive device and the quantitative piston continue to provide pressure for the molten metal liquid. When the molten metal in the mold cavity solidifies, the quantitative pressurizing drive device drives the quantitative piston to make a partial return stroke according to a preset displacement, so that the quantitative piston returns to below the origin position, so that the molten metal is suspended in the liquid lifting chamber, waiting for the next quantitative delivery, and repeating the quantitative and pressurizing drive multiple times. Pressurization, each return stroke is a partial return stroke, keeping the molten metal suspended in the lifting chamber, until the molten metal needs to be supplemented to the pressurization chamber, the quantitative pressurization drive device drives the quantitative piston back to the original position, and the insulation furnace plug rod makes a corresponding action, so that when the piston returns to the original position or thereafter, the chamber and the pressurization chamber are connected, so that the molten metal enters the pressurization chamber and the lifting chamber, and then the quantitative and pressurization are repeated many times, and each return stroke is a partial return stroke, keeping the molten metal suspended in the lifting chamber, until the molten metal needs to be supplemented to the pressurization chamber again, the quantitative pressurization drive device drives the quantitative piston back to the original position, and the cycle action is repeated.

8. A molten metal holding furnace as claimed in claim 7, characterized in that: When the liquid level of the molten metal in the holding chamber is equal to or lower than the height of the lower end surface of the metering piston when the metering piston is at the original position, the molten metal is added to the holding chamber.

9. A metal casting system, characterized in that: It comprises a casting machine and a molten metal holding furnace, wherein the molten metal holding furnace adopts the molten metal holding furnace of the structure described in any one of claims 4-8.

10. A metal casting system according to claim 9, characterized in that: The casting machine is one of a low-pressure casting machine, a high-pressure casting machine, a differential pressure casting machine or an extrusion casting machine, and is connected to the mold cavity of the casting machine through the liquid lifting chamber.

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