Smelting device and method for casting of castings

Abstract

The invention relates to the technical field of casting smelting furnaces, and discloses a smelting device and method for casting castings, the smelting device for casting castings comprises a furnace body, a furnace cover, a temperature regulation and control mechanism and a control end; the temperature regulation and control mechanism comprises a heating element, an in-furnace temperature measuring piece used for measuring the temperature of a main body in the furnace, an environment sensing piece used for sensing the temperature change of the environment in the furnace, and a furnace cover state sensing piece used for detecting the opening and closing states of the furnace cover; the control end is connected with the heating element, the in-furnace temperature measuring piece and the environment sensing piece. The temperature regulation and control mechanism is arranged to cooperate with the control end, and based on a feed-forward compensation mechanism, a dual-mode self-adaptive control strategy and an eddy current homogenization technology, pre-judgment type response and self-adaptive regulation and control on the temperature after the furnace cover is opened are achieved, the temperature in the furnace body can be rapidly recovered to be normal, and the service life of the furnace body is prolonged. The temperature control problem of well type resistance crucible furnaces in small and medium-sized casting workshops in a furnace cover opening scene is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of casting smelting furnace, more particularly, it relates to a smelting device and method for casting. BACKGROUND

[0002] In the smelting of aluminum alloy in small and medium-sized foundry workshops, well-type resistance crucible furnaces are commonly used equipment for batch smelting due to their simple structure, convenient operation and moderate cost. They are equipped with traditional PID temperature control systems based on single-point thermocouple feedback in the furnace, which can operate stably under normal production and meet the general requirements of casting smelting temperature control. However, with the acceleration of lightweight manufacturing in the manufacturing industry, the quality requirements for aluminum alloy castings are more stringent, and the control accuracy of smelting temperature is higher when producing critical components.

[0003] In the production of high-standard wind power aluminum alloy castings, operators often frequently open the furnace cover for sampling detection, adjustment of alloy composition or observation of the melt state. Taking a 500 kg well-type resistance crucible furnace as an example, the furnace cover is opened for 10-30 seconds, and cold air from the workshop rushes into the furnace, causing the temperature in the furnace to drop by 30-50℃ in 1-2 minutes, and the temperature drop is more obvious in winter, with a range exceeding 50℃. After closing the furnace cover, due to the high heat capacity of aluminum liquid and the temperature measurement lag of the thermocouple, the control system needs 5-10 minutes to sense the temperature change and start compensation heating.

[0004] During this process, the existing temperature control system faces three key challenges: first, the traditional PID control strategy is based on historical temperature data adjustment and cannot predict the opening of the furnace cover, resulting in a lag in temperature recovery response; second, to shorten the recovery time, operators manually increase the set power or use aggressive PID parameters, which can easily cause temperature overshoot, leading to excessive oxidation and hydrogen absorption of aluminum liquid, affecting the gas tightness and mechanical properties of the castings; third, the cold air affects the furnace mouth area, causing a significant temperature gradient in the furnace, even if the overall temperature returns to the set value, the temperature difference between the furnace mouth and the crucible bottom can still reach 15-20℃, affecting the microstructure consistency of high-quality castings.

[0005] In view of the above challenges, the industry has proposed various improvement schemes. Some research focuses on optimizing the PID control algorithm, such as introducing fuzzy PID or adaptive PID strategy, but in essence, it is a post-response to the temperature deviation that has already occurred, and it is difficult to fundamentally solve the lag problem of event triggering. High-end solutions use a full-furnace infrared temperature measurement system with multi-zone heating control, which can improve temperature uniformity, but the equipment cost is high, maintenance is complex, and it is not cost-effective for small and medium-sized foundry workshops with limited budgets. In addition, these schemes do not fully consider the prediction and rapid response mechanism of the furnace cover opening event, and there is still a problem of temperature fluctuation in the frequent opening cover scenario.

[0006] Therefore, there is an urgent need for a casting smelting device and method that can design a pre-judgment temperature control strategy for the furnace cover opening event without significantly increasing equipment costs, taking into account temperature recovery speed and uniformity. SUMMARY

[0007] The purpose of the present application is to provide a casting smelting device and method to solve the above technical problems.

[0008] The present application solves the above-mentioned technical problems by the following technical solutions: The present application provides a casting smelting device, comprising: a furnace body, a furnace cover, a temperature control mechanism, and a control end; The temperature control mechanism comprises: a heating element, a furnace temperature measuring element for measuring the temperature of the furnace body, an environment sensing element for sensing the change of the environment temperature in the furnace, and a furnace cover state sensing element for detecting the opening and closing state of the furnace cover; The control end is respectively connected in communication with the heating element, the furnace temperature measuring element, the environment sensing element, and the furnace cover state sensing element, and is configured to: Based on the furnace cover opening signal sent by the furnace cover state sensing element, the heating element is output with a feedforward compensation power to compensate for the expected heat loss caused by the influx of cold air before the furnace temperature drops significantly; Based on the furnace cover closing signal sent by the furnace cover state sensing element, according to the temperature data of the furnace temperature measuring element and the environment temperature change information of the environment sensing element, the control mode is dynamically switched: When the furnace temperature is lower than the set value threshold, a fast recovery control mode is adopted to accelerate the recovery of the furnace temperature; When the furnace temperature recovers to the vicinity of the set value, a steady-state temperature maintenance control mode is switched to maintain the temperature stable.

[0009] Preferably, the environment sensing element comprises at least two temperature sensors respectively arranged on the inside of the furnace cover and the upper space of the furnace body for sensing the temperature change at different positions in the furnace.

[0010] Preferably, the furnace cover state sensing element is an inductive switch arranged on the furnace cover.

[0011] Preferably, the feedforward compensation power is dynamically adjusted based on the furnace cover opening time and the furnace environment temperature, and slowly increases with the opening time during the furnace cover opening.

[0012] Preferably, the fast recovery control mode and the steady-state temperature maintenance control mode respectively adopt different PID control parameter sets; Among them, the proportional coefficient adopted by the fast recovery control mode is greater than the proportional coefficient adopted by the steady-state temperature maintenance control mode, and the integral time adopted by the fast recovery control mode is less than the integral time adopted by the steady-state temperature maintenance control mode.

[0013] Preferably, the control end predicts the temperature change trend in the furnace based on the temperature change rate of the environment sensing element, and reduces the heating power in advance according to the predicted trend to prevent temperature overshoot.

[0014] Preferably, a vortex generating element is arranged on the inner side of the furnace cover, and the control end is in communication connection with the vortex generating element. When the temperature fluctuation in the furnace exceeds a set threshold, the vortex generating element is started to promote uniform distribution of the temperature in the furnace.

[0015] Preferably, the control end is further configured to adjust the operation intensity of the vortex generating element according to the temperature difference between the temperature measuring element in the furnace and the environment sensing element.

[0016] A temperature control method of a foundry smelting device for castings, comprising the following operation steps: Step S100: detecting the opening and closing state of the furnace cover; Step S200: when it is detected that the furnace cover is opened, immediately outputting a feedforward compensation power to the heating element to compensate for the expected heat loss caused by the inflow of cold air; Step S300: when it is detected that the furnace cover is closed and the temperature in the furnace is lower than a set value threshold, based on the temperature change information of the main body in the furnace and the environment, adopting a fast recovery control mode to adjust the heating power to accelerate the temperature recovery; Step S400: when the temperature in the furnace recovers to the vicinity of the set value, switching to a steady-state temperature maintaining control mode to maintain the temperature stable; Step S500: returning to step S100 to continue monitoring the state of the furnace cover.

[0017] Preferably, in the step S300, when switching to the fast recovery control mode, the vortex generating element can be started to improve the uniformity of the temperature in the furnace.

[0018] The present application has the following advantages: The present application sets a temperature regulation mechanism, cooperates with the control end, and realizes the predictive response and adaptive regulation of the temperature after the furnace cover is opened based on the feedforward compensation mechanism, the double-mode adaptive control strategy and the vortex uniformization technology, so that the temperature in the furnace body can be quickly recovered to normal, and the temperature control problem of the small and medium-sized foundry workshop well-type resistance crucible furnace under the opening of the furnace cover is effectively solved. In addition, the present application can start precise compensation at the moment when the furnace cover is opened, greatly shortens the temperature recovery time, ensures the smoothness of the temperature recovery process without overshoot through intelligent mode switching and temperature trend prediction, and significantly improves the uniformity of the temperature distribution in the furnace by using the vortex technology, so as to comprehensively improve the quality of the aluminum liquid and the process stability. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 is a structural schematic diagram of a smelting device for casting foundry; Fig. 2 is a structural schematic diagram of the inside of a smelting device for casting foundry; Fig. 3 is a relationship block diagram between a temperature regulating mechanism and a control end in a smelting device for casting foundry; Fig. 4 is a flow chart of a temperature control method of a smelting device for casting foundry.

[0020] In the figure: 10, furnace body; 20, furnace cover; 30, temperature regulating mechanism; 301, heating element; 302, furnace temperature measuring element; 303, environment sensing element; 304, furnace cover state sensing element; 305, vortex generating element. DETAILED DESCRIPTION

[0021] The subject matter described herein will now be discussed with reference to example implementations. It should be understood that the discussion of these implementations is merely meant to provide a better understanding of the subject matter described herein and can be changed in function and arrangement without departing from the scope of the disclosure. Various examples can omit, substitute, or add various procedures or components as appropriate. Also, features described with respect to some examples can be combined in other examples.

[0022] Please refer to Figs. 1 to 4 A smelting device for casting foundry, comprising: a furnace body 10, a furnace cover 20, a temperature regulating mechanism 30, and a control end. The furnace cover 20 is configured with a driving mechanism, which can realize automatic opening and closing. The temperature regulating mechanism 30 comprises: a heating element 301, a furnace temperature measuring element 302, an environment sensing element 303, a furnace cover state sensing element 304, and a vortex generating element 305. The heating element 301 is a conventional heating resistor, which is arranged in the furnace body 10 and is mainly used for heating the material in the furnace body 10. The furnace temperature measuring element 302 is mainly used for measuring the temperature of the furnace body, generally adopts K-type thermocouple, is installed in the furnace chamber at a distance of 5-8 cm from the surface of the aluminum liquid, and is used for collecting the temperature of the core temperature measuring point.

[0023] The environment sensing element 303 is used for quickly capturing the cold shock of the opening of the furnace cover 20 and the temperature gradient change in the furnace. The environment sensing element 303 comprises two temperature sensors, both of which are selected from K-type armored thermocouples. One of the temperature sensors is fixed by high-temperature resistant bolts in the center area of the inside of the furnace cover 20, at a distance of about 15-20 cm from the edge of the furnace cover 20, and is most sensitive to the inflow of cold air. The other temperature sensor is installed on the side wall at a distance of 30-40 cm from the opening of the furnace body 10, and can monitor the convection state of hot air.

[0024] The furnace cover state sensing member 304 is used to detect the opening and closing state of the furnace cover 20, and can adopt a door magnetic switch or an angle sensor. The door magnetic switch or the angle sensor is installed on the furnace body 10 along the abutting position of the edge of the furnace cover 20. When the opening angle of the furnace cover 20 is greater than or equal to 15°, a low-level signal is output, and when the furnace cover 20 is closed, a high-level signal is output. The response delay of the on-off signal is less than or equal to 10 ms, so that the state change of the furnace cover 20 can be captured in real time.

[0025] The vortex generating member 305 is arranged at the inner edge position of the furnace cover 20. The vortex generating member 305 can be a small fan made of a high-temperature-resistant material and driven by a small pneumatic motor or a high-temperature-resistant motor. The vortex generating member 305 is in communication connection with the control end. The vortex generating member 305 generates controllable vortex after being powered on, stirs the atmosphere in the furnace, and promotes the uniform distribution of heat.

[0026] The control end adopts an industrial PLC, which integrates temperature acquisition, logic control and communication functions. The control end is in communication connection with the heating element 301, the in-furnace temperature sensing member 302, the environment sensing member 303 and the furnace cover state sensing member 304.

[0027] The feedforward compensation module generates a feedforward compensation strategy, that is, a feedforward power , which is mainly obtained through the following formula: ; It should be noted that the design thermodynamic principle of the formula is as follows: the basic law of heat convection (the heat loss rate caused by the inflow of cold air is proportional to the difference between the environmental temperature and the in-furnace temperature), the principle of conservation of mass (the longer the furnace cover is opened, the greater the total amount of cold air entering the furnace), and the principle of conservation of energy (the compensation power needs to be matched with the expected heat loss to maintain thermal equilibrium). Through analysis of the heat exchange mechanism during the opening of the furnace cover 20, the total heat loss is decomposed into three key influencing factors: basic heat loss, environmental temperature influence and opening time influence, which correspond to the three multiplier terms in the formula.

[0028] In the formula, P base is the rated power of the furnace, T ambient is the workshop environmental temperature, and t open is the opening time (seconds) of the furnace cover 20, which is generally a preset fixed time.

[0029] 0.2 is a basic compensation coefficient, which is obtained based on multiple tests. 100 times of benchmark tests on a 500 kg pit type resistance crucible furnace show that, under standard working conditions (workshop temperature of 20°C), the heat loss rate caused by the inflow of cold air at the moment when the furnace cover 20 is opened is about 20% of the rated power. This value represents the minimum effective compensation amount required to offset the initial cold impact under typical working conditions, so as to ensure that thermal equilibrium is established before the actual temperature drops.

[0030] The temperature compensation term is designed based on the principle that temperature difference is the driving force of heat transfer, and the heat loss rate is proportional to the temperature difference according to Newton's cooling law. Through experiments, it is found that the heat loss increases by about 5% when the ambient temperature decreases by 10°C. Taking 20°C as the reference temperature (typical workshop temperature), a linear compensation relationship is established.

[0031] 0.01×t open The opening time compensation term is designed based on the principle that the longer the furnace cover 20 is opened, the more cold air flows in, and the heat loss accumulates approximately linearly. Experiments show that for every 10 seconds of opening, an additional 1% of compensation power is required. A linear model is used because the heat loss is related to time within a typical opening time of 0-60 seconds, with a correlation coefficient R²>0.95. The dynamic adjustment mechanism is that the compensation power increases by 1% every 10 seconds. An upper limit is set (total compensation not exceeding 25%) to prevent excessive compensation caused by long-term opening (>50 seconds). The PLC calculates t open in real time to ensure accurate compensation matching the actual opening time. Actual measurement results show that for a typical 20-second opening operation, the total compensation power is 22%, and the temperature drop is from 50°C to 18°C.

[0032] The specific process executed by the control end when the furnace cover 20 is opened is as follows: Step one, feedforward compensation of the furnace cover 20 opening event: When the control end receives the opening signal detected by the furnace cover state sensing device, it immediately triggers the feedforward compensation module to perform feedforward compensation action. The feedforward compensation module calculates the feedforward power based on the received data and pre-stored known data. Then, the control end outputs the calculated feedforward power to the heating element 301, so that the heating element 301 adjusts the heating strategy in advance and outputs compensation power in time at the opening moment to offset the heat loss of cold air.

[0033] Step two, dynamic mode switching after the furnace cover 20 is closed: When the control end receives the closing signal detected by the furnace cover state sensing device 304, it continuously receives the temperature data T main uploaded by the environment sensing device 303 and compares it with the pre-set target temperature value T set in the furnace. If T main <T set -5°C, the fast recovery control mode is started, using high-response PID parameters, the proportional coefficient K p =8.0, the integral time T i =60s, and the power output upper limit is set to 1.5×P base to accelerate temperature recovery. If Tset -2℃≤T main ≤T set If the temperature increases by 2℃, the steady-state heat preservation control mode will be activated, using low-response PID parameters and a proportional coefficient K. p =2.5, integration time T i =300s, power output limit ±10%, suppressing fluctuations; Mode switching logic: During the temperature recovery process, if T main If the upward slope is greater than 1.5℃ / min for 20 consecutive seconds, it is determined that the system has entered a rapid recovery phase, and the target power should be reduced in advance.

[0034] Step 3, Multi-point Prediction Overshoot Prevention Mechanism: During the temperature recovery process after the furnace lid 20 is closed, the control terminal continuously receives temperature data from the environmental sensing element 303 and calculates the temperature change trend in real time; based on the historical readings of the two temperature sensors, the control terminal calculates the temperature change rate every 10 seconds. ; ; Then, the control unit compares the calculated temperature change rate with the preset threshold. If ΔT1>3℃ / min and ΔT2>2℃ / min, it is determined that the furnace temperature is about to enter a rapid recovery phase. The control unit immediately activates the predictive compensation mechanism to reduce the target heating power by 15%-20% in advance. It should be noted that the prediction threshold is set based on a large amount of experimental data to ensure that power adjustment begins 20-30 seconds before the actual temperature rises. Through this mechanism, the system can actively reduce the heating intensity before the temperature approaches the target value, effectively avoiding temperature overshoot caused by thermal inertia, making the temperature recovery curve smoother, and ultimately controlling the overshoot within +4℃.

[0035] Step 4, Cooperative control of eddy current generators: During the execution of the fast recovery control mode in step two or the predictive overshoot prevention process in step three, the control terminal continuously monitors the temperature distribution inside the furnace and calculates the difference ΔT between the main control temperature and the average temperature of the environmental sensing device. diff And compare it with the preset threshold of 8℃; if ΔT diff If the temperature exceeds 8℃, it is determined that there is significant temperature unevenness inside the furnace, and the control terminal immediately activates the eddy current generator. After startup, the control terminal calculates the real-time temperature difference ΔT. diff Precise calculation of the operating intensity of the eddy current generator 305: Operating intensity = 0.5 × ΔT diff (Unit: PWM duty cycle percentage); For example, when the temperature difference is 10℃, the PWM duty cycle is automatically set to 50%; at the same time, the control end limits the maximum operating strength of the vortex generator to 80% to avoid excessive disturbance of the aluminum liquid surface causing oxidation; In terms of operation duration control, the system initially operates for 60 seconds, and then re-evaluates the temperature difference state every 30 seconds; when the temperature difference drops to within 5℃, the control end gradually reduces the operating strength (by 10% every 30 seconds) until it is completely turned off; The vortex control and temperature recovery process are closely coordinated: in the fast recovery mode of step two, the vortex generator 305 accelerates the uniform distribution of heat in the furnace, shortening the overall temperature recovery time; in the steady-state heat preservation mode of step two, it is only started for a short time when temperature unevenness is detected, maintaining the consistency of the temperature in the furnace and ensuring the stability of the aluminum liquid quality; It should be noted that, in order to avoid the problem of vortex disturbance of the liquid surface caused by the operation of the vortex generator affecting the process stability, the use of the vortex generator in the present application needs to be strictly controlled, it is not always working, but only starts when the temperature fluctuation in the furnace exceeds the set threshold or the temperature difference between the temperature sensing element in the furnace and the environmental sensing element is large, its use is targeted and intermittent, mainly used to eliminate abnormal temperature gradient, and stops running immediately after the abnormality ends, if the operation duration reaches the danger threshold, the control end will also choose to temporarily stop the operation of the vortex generator, rather than continuously disturb, to ensure that the furnace is in a stable environment; secondly, the control end also adjusts the operating strength of the vortex generator according to the temperature difference, rather than in full power operation state, aiming to improve uniformity just in the case of minimum effective disturbance, while controlling the temperature difference in the furnace.

[0036] From the above scheme, it can be seen that the present application, by setting the temperature regulation mechanism 30, cooperates with the control end based on the feedforward compensation mechanism, the double-mode adaptive control strategy and the vortex uniformization technology, realizes the pre-judgment response and adaptive regulation of the temperature after the furnace cover 20 is opened, can make the temperature in the furnace body 10 quickly recover to normal, effectively solves the temperature control problem of the small and medium-sized foundry workshop well-type resistance crucible furnace in the scene of opening the furnace cover 20; Secondly, the present application can start precise compensation at the moment of opening the furnace cover 20, greatly shorten the temperature recovery time, ensure the smoothness of the temperature recovery process without overshoot through intelligent mode switching and temperature trend prediction, and significantly improve the uniformity of the temperature distribution in the furnace by using vortex technology, thereby comprehensively improving the quality of the aluminum liquid and the process stability; In addition, the present application only needs to add a small amount of low-cost sensors and optimize the control software, without the need for large-scale modification of the existing equipment, and is particularly suitable for implementation in small and medium-sized foundry workshops with limited budget, providing reliable technical support for the production of high-standard aluminum alloy castings, and has significant technical advancement and practical popularization value.

[0037] The above describes the embodiments of the present application, but the present application is not limited to the above-described specific embodiments, and the above-described specific embodiments are only illustrative but not restrictive, and those skilled in the art can make many forms under the inspiration of the present application, which all belong to the protection of the present application.

Claims

1. A smelting apparatus for casting, characterized in that, The application relates to a temperature control device for a cooking device, comprising: a furnace body, a furnace cover, a temperature control mechanism and a control terminal; the temperature control mechanism comprises a heating element, an in-furnace temperature measuring element for measuring the temperature of the furnace body, an environment sensing element for sensing the change of the environment temperature in the furnace, and a furnace cover state sensing element for detecting the opening and closing state of the furnace cover; the control terminal is in communication connection with the heating element, the in-furnace temperature measuring element, the environment sensing element and the furnace cover state sensing element, and is configured to: based on the furnace cover opening signal sent by the furnace cover state sensing element, output a feedforward compensation power to the heating element to compensate for the expected heat loss caused by the inflow of cold air before the temperature in the furnace obviously decreases; based on the furnace cover closing signal sent by the furnace cover state sensing element, dynamically switch the control mode according to the temperature data of the in-furnace temperature measuring element and the environment temperature change information of the environment sensing element: when the temperature in the furnace is lower than a set value threshold, a rapid recovery control mode is adopted to accelerate the temperature recovery in the furnace; when the temperature in the furnace recovers to the vicinity of the set value, a steady-state temperature maintaining control mode is switched to maintain the temperature stability. The environment sensing element comprises at least two temperature sensors arranged on the inner side of the furnace cover and the upper space of the furnace body respectively for sensing the temperature change at different positions in the furnace. The furnace cover state sensing element is an inductive switch arranged on the furnace cover. The feedforward compensation power is dynamically adjusted based on the furnace cover opening time length and the in-furnace environment temperature, and slowly increases with the extension of the opening time during the furnace cover opening. The rapid recovery control mode and the steady-state temperature maintaining control mode adopt different PID control parameter sets respectively. The proportional coefficient adopted by the rapid recovery control mode is greater than the proportional coefficient adopted by the steady-state temperature maintaining control mode, and the integral time adopted by the rapid recovery control mode is smaller than the integral time adopted by the steady-state temperature maintaining control mode. The control terminal predicts the temperature change trend in the furnace based on the temperature change rate of the environment sensing element, and reduces the heating power in advance according to the predicted trend to prevent temperature overshoot. The inner side of the furnace cover is provided with an eddy current generating element, and the control terminal is in communication connection with the eddy current generating element.

2. The casting melting apparatus according to claim 1, characterized by When the temperature fluctuation in the furnace exceeds a set threshold, the eddy current generating element is started to promote the uniform distribution of the temperature in the furnace.

3. The casting melting apparatus according to claim 1, characterized by The control terminal is further configured to adjust the operation intensity of the eddy current generating element according to the temperature difference between the in-furnace temperature measuring element and the environment sensing element.

4. The casting melting apparatus according to claim 1, characterized by The application further discloses a temperature control method for a cooking device, comprising the following operation steps: step S100: detecting the opening and closing state of the furnace cover; step S200: when the furnace cover is detected to be opened, immediately outputting a feedforward compensation power to the heating element to compensate for the expected heat loss caused by the inflow of cold air; step S300: when the furnace cover is detected to be closed and the temperature in the furnace is lower than a set value threshold, based on the in-furnace body temperature and the environment temperature change information, adopting a rapid recovery control mode to adjust the heating power to accelerate the temperature recovery; step S400: when the temperature in the furnace recovers to the vicinity of the set value, switching to a steady-state temperature maintaining control mode to maintain the temperature stability; and step S500: returning to step S100 to continue monitoring the furnace cover state.

5. The casting melting apparatus according to claim 1, wherein In the step S300, when the rapid recovery control mode is switched to, the eddy current generating element can be started to improve the uniformity of the temperature in the furnace. ​ 6. The casting melting apparatus according to claim 1, wherein ​ 7. The casting melting apparatus according to claim 1, wherein ​ ​ 8. The casting melting apparatus according to claim 7, wherein ​ 9. A temperature control method of a casting melting apparatus for casting, using the casting melting apparatus for casting according to any one of claims 1 to 8, characterized by, ​ ​ ​ ​ ​ ​ 10. The temperature control method of a melting apparatus for casting of a casting according to claim 9, characterized by, ​

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