Optimization method and system for regulating and controlling temperature uniformity of mesh belt furnace

Abstract

The invention relates to an optimization method and system for regulating and controlling the temperature uniformity of a mesh belt furnace, and belongs to the technical field of mesh belt furnaces, and the optimization method comprises the following steps: step 1, arranging a flowmeter and a thermometer in a protective gas introduction pipe; 2, a flowmeter and a thermometer detect the introduced protective gas in real time and upload flow and temperature data to a control module; and 3, the control module calculates a gas temperature coefficient according to the flow and the temperature data and judges whether the gas temperature coefficient exceeds a first threshold value or not, and when the judgment result is yes, the control module improves the heating power of the furnace chamber around the protective gas introduction position.

Description

Technical Field

[0001] The present invention belongs to the technical field of mesh belt furnaces, and in particular relates to an optimization method and system for regulating the temperature uniformity of a mesh belt furnace. Background Art

[0002] The mesh belt furnace is a sintering furnace that uses a mesh belt to continuously transport parts within the furnace. It is mainly used for sintering powder metallurgy products, reducing metal powders, and pre-firing, firing or heat treatment processes of electronic products in a protective atmosphere or air.

[0003] For mesh belt furnaces, temperature uniformity is a key performance characteristic. To improve this, existing technologies, such as Chinese Patent CN111560502B (Mesh Belt Furnace and Porous Medium Gas Burner), disclose a mesh belt furnace and a porous medium gas burner. The mesh belt furnace includes a quenching furnace and / or a tempering furnace. The quenching furnace includes a first furnace body; the first furnace body includes a first preheating zone, a first heating zone, a holding zone, and a quenching tank, arranged in sequence. The tempering furnace includes a second furnace body; the second furnace body includes a second preheating zone, a second heating zone, and a cooling zone, arranged in sequence. Porous medium gas burners are installed on the top and / or sides of the first heating zone and the top and / or sides of the second heating zone. If both a furnace and a tempering furnace are present, a mesh belt drive system may also be included, connecting the quenching furnace and the tempering furnace via a mesh belt. The porous medium burner, through the use of convection, conduction, and radiation, uniformizes the temperature of the combustion area and maintains a relatively stable temperature gradient.

[0004] In some processes, protective gas needs to be continuously introduced into the mesh belt furnace during operation. There is a temperature difference between the protective gas and the furnace. In some cases, more protective gas needs to be temporarily introduced. At this time, there is a high probability of causing local temperature fluctuations. In the above cases, the local temperature adjustment response mechanism is not set, the instantaneous temperature adjustment effect is low, and the temperature uniformity guarantee effect is insufficient. Therefore, an optimization method and system for controlling the temperature uniformity of the mesh belt furnace is needed, which can cope with the instantaneous adjustment of local temperature and have a good temperature uniformity guarantee effect. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides an optimization method and system for regulating the temperature uniformity of a mesh belt furnace, which has the characteristics of good temperature uniformity assurance effect.

[0006] The purpose of the present invention can be achieved through the following technical solutions: An optimization method for controlling the temperature uniformity of a mesh belt furnace comprises the following steps: Step 1: Install a flow meter and a thermometer in the protective gas inlet pipe; Step 2: The flow meter and thermometer detect the incoming protective gas in real time and upload the flow and temperature data to the control module; Step 3: The control module calculates the gas temperature coefficient based on the flow rate and temperature data, and determines whether the gas temperature coefficient exceeds the first threshold. If the judgment result is yes, the control module increases the heating power of the furnace cavity around the protective gas introduction position.

[0007] As a preferred technical solution of the present invention, the step 1 further includes: setting a detection module in the mesh belt furnace; the step 2 further includes: a flow meter and a thermometer to detect the introduced protective gas in real time and upload the flow data L and the temperature data W to the control module, the detection module is used to detect the temperature Wl in the furnace and upload it to the control module; the step 3 further includes: the control module generates a function f(t) of the flow data L changing with time t, the control module calculates the gas temperature coefficient X based on the flow and temperature data, and the control module corrects the heating power of the furnace cavity around the protective gas introduction position upward by A1 times, where X=A2× dt, A1=X / X0, A2=1+(|W-Wl|) / Wl, X0 is the first threshold input in advance, W≤Wl.

[0008] As a preferred technical solution of the present invention, the step one also includes: setting an air intake zone and a diffusion zone in the furnace, the air intake zone is located around the protective gas introduction position, and the diffusion zone is located around the air intake zone, and the air intake zone or the diffusion zone is spherical or cubic; the step three also includes: when the judgment result is yes, the control module upward corrects the increase rate of the heating power of the air intake zone, and increases the heating power of the diffusion zone accordingly.

[0009] As a preferred technical solution of the present invention, step three also includes: the control module corrects the heating power of the air intake zone upward by A1×A3 times, and increases the heating power of the diffusion zone by A3 times, wherein A3=L / L0×e, e is a pre-input correction coefficient, and L is the diameter or side length of the air intake zone.

[0010] As an optimal technical solution of the present invention, the step one also includes: setting a dissipation zone in the furnace, the dissipation zone is located at the inlet and outlet of the mesh belt furnace; the step two also includes: the detection module is used to monitor the gas outflow rate of the mesh belt furnace dissipation zone and upload it to the control module; the step three also includes: the control module determines whether the gas outflow rate exceeds the threshold, and increases the heating power of the dissipation zone when the judgment result is yes.

[0011] As a preferred technical solution of the present invention, step 2 also includes: the detection module is used to monitor the gas outflow velocity C in the dissipation zone of the mesh belt furnace and upload it to the control module; step 3 also includes: the control module increases the heating power of the dissipation zone by A4 times, A4=C / C0×f, and f is a pre-input correction coefficient.

[0012] A system for regulating the temperature uniformity of a mesh belt furnace is applicable to the above-mentioned optimization method for regulating the temperature uniformity of a mesh belt furnace, comprising a mesh belt furnace, a control module and an air intake module, wherein the air intake module comprises a protective gas inlet pipe and a heating module, wherein the heating module is used to heat the gas in the protective gas inlet pipe, and a flow meter and a thermometer are arranged in the protective gas inlet pipe, wherein the flow meter and the thermometer perform real-time detection of the introduced protective gas and upload the flow and temperature data to the control module.

[0013] The beneficial effects of the present invention are: By setting a control module to calculate the gas temperature coefficient based on the flow rate and temperature data, and judging whether the gas temperature coefficient exceeds a first threshold, the control module increases the heating power of the furnace cavity around the position where the protective gas is introduced when the judgment result is yes. When a large amount of protective gas is temporarily introduced, which has a high probability of causing local temperature fluctuations, a local temperature adjustment response mechanism is established, which has a better instantaneous temperature adjustment effect and improves temperature uniformity; By making the control module according to X=A2× dt, A1=X / X0, A2=1+(|W-Wl|) / Wl to calculate the gas temperature coefficient X, and complete the continuous accumulation of flow over time and the temperature difference between the protective gas and the furnace as the gas temperature coefficient. This improves the representativeness of the gas temperature coefficient for the impact of the incoming gas on the furnace environment, thereby improving the accuracy of heating power adjustment based on the gas temperature coefficient; By setting up an intake zone and a diffusion zone in the furnace, when it is determined that the gas temperature coefficient exceeds a first threshold, the increase rate of the heating power in the intake zone is upwardly revised, and the heating power in the diffusion zone is increased accordingly. The control target can be independently designed for each sub-zone, further improving the adjustment accuracy; BRIEF DESCRIPTION OF THE DRAWINGS

[0014] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0015] Figure 1 This is a control loop block diagram of the present invention. DETAILED DESCRIPTION

[0016] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0017] See also Figure 1 , an optimization method for controlling the temperature uniformity of a mesh belt furnace, comprising the following steps: Step 1: Install a flow meter and a thermometer in the protective gas inlet pipe; Step 2: The flow meter and thermometer detect the incoming protective gas in real time and upload the flow and temperature data to the control module; In this embodiment, specifically, the mesh belt furnace is a standard linear mesh belt furnace, and the furnace cavity is a rectangular parallelepiped. The parts are fed into the furnace cavity through the mesh belt and heated to achieve sintering in the furnace. An air intake module is pre-installed in the mesh belt furnace. The air intake module includes a protective gas inlet pipe and a heating module. The heating module is used to heat the gas in the protective gas inlet pipe. In this embodiment, the heating module is an electric heater arranged outside the protective gas inlet pipe. The heating module is electrically connected to the control module, and the operating power of the heating module is controlled by the control module. After the heating module is installed, the temperature of the protective gas can be made close to the temperature in the furnace cavity. When the heated protective gas is introduced into the furnace cavity, the temperature change in the furnace cavity is relatively small. A flow meter and a thermometer are set in the shielding gas inlet pipe. The flow meter detects the flow of the shielding gas in real time and uploads the flow data to the control module once per second. The thermometer detects the temperature of the shielding gas in real time and uploads the temperature data to the control module once per second. During the use of the mesh belt furnace, a large amount of protective gas may sometimes be lost, and it is necessary to temporarily introduce more protective gas. Even if a heating module is installed, the protective gas inlet pipe cannot completely simulate the environment inside the mesh belt furnace, resulting in a deviation between the temperature inside the protective gas inlet pipe and the mesh belt furnace. When temporarily introducing more protective gas, it is necessary to increase the heating power of the furnace cavity around the gas introduction position; At the same time, if only a simple fixed threshold judgment is performed on the shielding gas introduced based on real-time flow parameters or temperature parameters, when the shielding gas temperature approaches the threshold but does not exceed the threshold for a long time, the shielding gas has a greater impact on the temperature in the furnace than when it exceeds the threshold for a short time. However, the alarm mechanism based on the fixed threshold judgment based on real-time flow parameters or temperature parameters cannot be triggered, resulting in low detection accuracy, which in turn leads to low adjustment accuracy. To this end, in step 3, the control module calculates the gas temperature coefficient based on the flow data and temperature data each time, and determines whether the gas temperature coefficient exceeds the first threshold. If the judgment result is yes, the control module increases the heating power of the furnace cavity around the protective gas introduction position; By setting a control module to calculate the gas temperature coefficient based on the flow rate and temperature data, and judging whether the gas temperature coefficient exceeds a first threshold, the control module increases the heating power of the furnace cavity around the protective gas introduction position when the judgment result is yes. When a large amount of protective gas is temporarily introduced and there is a high probability of causing local temperature fluctuations, a local temperature adjustment response mechanism is established, which has a better instantaneous temperature adjustment effect and improves the temperature uniformity assurance effect; For the calculation process of the temperature coefficient of the temperature gas, step one also includes: setting a detection module in the mesh belt furnace; step two also includes: a flow meter and a thermometer perform real-time detection on the introduced protective gas and upload the flow data L and temperature data W to the control module, the detection module is used to detect the temperature Wl in the furnace and upload it to the control module; step three also includes: the control module generates a function f(t) of the flow data L changing with time t, the control module calculates the gas temperature coefficient X based on the flow and temperature data, and the control module corrects the heating power of the furnace cavity around the protective gas introduction position upward by A1 times, where X=A2× dt, A1=X / X0, A2=1+(|W-Wl|) / Wl, X0 is the pre-entered first threshold, W≤Wl, t0 is the pre-entered standard acquisition time; dt is the continuous accumulation of f(t) over time, representing the cumulative amount of gas introduced during the past t0 period, while A2 represents the temperature difference between the protective gas and the furnace. The greater the temperature difference, the larger A2, the larger the temperature coefficient, and the greater the impact on the furnace; By making the control module according to X=A2× dt, A1=X / X0, A2=1+(|W-Wl|) / Wl to calculate the gas temperature coefficient X, and complete the continuous accumulation of flow over time and the temperature difference between the protective gas and the furnace as the gas temperature coefficient, which improves the representativeness of the gas temperature coefficient for the impact of the incoming gas on the furnace environment, thereby improving the accuracy of heating power adjustment based on the gas temperature coefficient; In the above process, in order to improve the control accuracy, it is necessary to zone and regulate each area in the mesh belt furnace, and divide the areas. To this end, step one also includes: setting an air intake area and a diffusion area in the furnace, the air intake area is located around the protective gas introduction position, and the diffusion area is located around the air intake area, and the air intake area or the diffusion area is spherical or cubic; step three also includes: when the judgment result is yes, the control module upward corrects the increase rate of the heating power of the air intake area, and increases the heating power of the diffusion area accordingly.

[0018] By setting up an intake zone and a diffusion zone in the furnace, and upwardly correcting the increase rate of the heating power in the intake zone when the gas temperature coefficient exceeds a first threshold, and correspondingly increasing the heating power in the diffusion zone, it is possible to independently design control targets for each sub-zone, further improving adjustment accuracy; Regarding the adjustment calculation process for each area, specifically, step three also includes: the control module corrects the heating power of the intake zone upward by A1×A3 times, and increases the heating power of the diffusion zone by A3 times, where A3=L / L0×e, e is the pre-input correction coefficient, and L is the diameter or side length of the intake zone.

[0019] In addition to the introduction of gas, gas escape will still cause the temperature in the furnace to change. In order to reduce the impact of this factor on temperature consistency, step one also includes: setting a escape zone in the furnace, and the escape zone is located at the inlet and outlet of the mesh belt furnace; step two also includes: a detection module is used to monitor the gas outflow rate of the mesh belt furnace escape zone and upload it to the control module; step three also includes: the control module determines whether the gas outflow rate exceeds the threshold, and increases the heating power of the escape zone when the judgment result is yes.

[0020] Step 2 also includes: the detection module is used to monitor the gas outflow velocity C in the escape zone of the mesh belt furnace and upload it to the control module; Step 3 also includes: the control module increases the heating power of the escape zone by A4 times, A4=C / C0×f, and f is a pre-input correction coefficient.

[0021] A system for regulating the temperature uniformity of a mesh belt furnace is applicable to the above-mentioned optimization method for regulating the temperature uniformity of a mesh belt furnace, comprising a mesh belt furnace, a control module and an air intake module. The air intake module comprises a protective gas inlet pipe and a heating module. The heating module is used to heat the gas in the protective gas inlet pipe. A flow meter and a thermometer are arranged in the protective gas inlet pipe. The flow meter and the thermometer detect the introduced protective gas in real time and upload the flow and temperature data to the control module.

[0022] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An optimization method for controlling the temperature uniformity of a mesh belt furnace, characterized by: The following steps are involved: Step 1: Install a flow meter and a thermometer in the protective gas inlet pipe; Step 2: The flow meter and thermometer detect the incoming protective gas in real time and upload the flow and temperature data to the control module; Step 3: The control module calculates the gas temperature coefficient based on the flow rate and temperature data, and determines whether the gas temperature coefficient exceeds the first threshold. If the judgment result is yes, the control module increases the heating power of the furnace cavity around the protective gas introduction position.

2. The method for optimizing the temperature uniformity of a mesh belt furnace according to claim 1, characterized in that: The step 1 further includes: setting a detection module in the mesh belt furnace; the step 2 further includes: a flow meter and a thermometer to detect the introduced protective gas in real time and upload the flow data L and the temperature data W to the control module, the detection module is used to detect the temperature Wl in the furnace and upload it to the control module; the step 3 further includes: the control module generates a function f(t) of the flow data L changing with time t, the control module calculates the gas temperature coefficient X based on the flow and temperature data, and the control module corrects the heating power of the furnace cavity around the protective gas introduction position upward by A1 times, where X=A2× dt, A1=X / X0, A2=1+(|W-Wl|) / Wl, X0 is the pre-input first threshold, W≤Wl, t0 is the pre-input standard acquisition time.

3. The method for optimizing the temperature uniformity of a mesh belt furnace according to claim 2, characterized in that: The step one also includes: setting an air intake zone and a diffusion zone in the furnace, the air intake zone is adjacent to the position where the protective gas enters the furnace chamber, the diffusion zone is adjacent to the air intake zone, and the air intake zone and the diffusion zone are spherical or cubic; the step three also includes: when the judgment result is yes, the control module upwardly corrects the increase rate of the heating power of the air intake zone, and correspondingly increases the heating power of the diffusion zone.

4. The method for optimizing the temperature uniformity of a mesh belt furnace according to claim 3, characterized in that: The step three also includes: the control module corrects the heating power of the air intake zone upward by A1×A3 times, and increases the heating power of the diffusion zone by A3 times, wherein A3=L / L0×e, e is a pre-input correction coefficient, and L is the diameter or side length of the air intake zone.

5. The method for optimizing the temperature uniformity of a mesh belt furnace according to claim 4, characterized in that: The step one also includes: setting a dissipation zone in the furnace, the dissipation zone is located at the inlet and outlet of the mesh belt furnace; the step two also includes: the detection module is used to monitor the gas outflow rate of the mesh belt furnace dissipation zone and upload it to the control module; the step three also includes: the control module determines whether the gas outflow rate exceeds the threshold, and increases the heating power of the dissipation zone when the judgment result is yes.

6. The method for optimizing the temperature uniformity of a mesh belt furnace according to claim 5, characterized in that: The second step also includes: the detection module is used to monitor the gas outflow velocity C in the dissipation zone of the mesh belt furnace and upload it to the control module; the third step also includes: the control module increases the heating power of the dissipation zone by A4 times, A4=C / C0×f, and f is a pre-input correction coefficient.

7. A system for regulating the temperature uniformity of a mesh belt furnace, characterized by: An optimization method for controlling the temperature uniformity of a mesh belt furnace applicable to any one of claims 1 to 6, comprising a mesh belt furnace, a control module and an air intake module, wherein the air intake module comprises a protective gas inlet pipe and a heating module, wherein the heating module is used to heat the gas in the protective gas inlet pipe, and a flow meter and a thermometer are arranged in the protective gas inlet pipe, wherein the flow meter and the thermometer perform real-time detection of the introduced protective gas and upload the flow and temperature data to the control module.

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