High temperature furnace system for heating a gas

Abstract

This invention relates to the field of furnace heating technology and discloses a high-temperature furnace system for heating gas, including a furnace body, a power supply system, and a transmission rod. The system contains a multi-layered metal furnace core, which consists of several layers of parallel-stacked high-temperature resistant metal plates. Adjacent metal plates are fixed together by spacer supports. This invention achieves efficient and uniform heating through multi-layered microchannels, with an outlet gas temperature uniformity better than ±5℃. The multi-layered metal furnace core consists of 6 to 18 layers of parallel-stacked high-temperature resistant metal plates with a thickness of 0.6 to 2 mm. Adjacent plates are separated by ceramic spacers to form uniform fluid channels of 0.4 to 1.5 mm. Inert gas flows through each channel in a laminar or transitional flow state, fully exchanging heat with the high-temperature metal plates, eliminating the radial temperature gradient of traditional single-tube heaters, and ensuring that the outlet gas temperature uniformity is stably controlled within ±5℃, meeting the stringent process requirements of semiconductor manufacturing, material synthesis, and other fields.

Description

Technical Field

[0001] This invention belongs to the field of furnace heating technology, and particularly relates to a high-temperature furnace system for heating gases. Background Technology

[0002] In fields such as semiconductor manufacturing, advanced materials synthesis, metallurgical heat treatment, aerospace thermal barrier coating testing, and high-temperature gas-cooled reactors, the demand for continuous or static high-temperature heating of inert gases (such as Ar, N2, and He) at temperatures above 800–2000°C is increasing. Currently, tube furnaces and inline gas heaters are the mainstream technologies.

[0003] Tubular furnaces, as a classic resistance heating device, heat gases through radiation within a ceramic working tube. However, they suffer from limited heating element lifespan and susceptibility to thermal shock cracking of the ceramic tube, leading to insufficient reliability and high maintenance costs during continuous industrial operation. Channel-type electric heaters achieve rapid convection heating through compact channels embedded with resistance elements, but their element durability and gas uniformity heating capabilities are insufficient at extremely high temperatures (>1200℃). Therefore, existing high-temperature inert gas heating devices generally suffer from poor heating uniformity and short heating element lifespan during continuous flow heating at 800–1300℃. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a high-temperature furnace system for heating gas.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a high-temperature furnace system for heating gas, including a furnace body, a power supply system and a transmission rod, wherein a multi-layer metal furnace core is provided inside, the multi-layer metal furnace core is composed of several layers of parallel stacked high-temperature resistant metal plates, and adjacent metal plates are fixed by spacer supports to form a fluid channel at the micron to millimeter level. The air inlet pipe and the air outlet pipe are respectively connected to the furnace body; A heating system, located on the outside of the multi-layer metal furnace core, is used to supply heat to the metal plates; Control system, used to control the power of the heating system; The inert gas flows in laminar or transitional flow within the fluid channel, achieving a uniform outlet gas temperature within ±5℃.

[0006] Preferably, the multi-layer metal furnace core is composed of 6 to 18 layers of high-temperature resistant metal plates with a thickness of 0.6 to 2 mm stacked in parallel; the spacer support is composed of 4 to 8 ceramic spacer columns with a diameter of 1.5 to 3.5 mm and a height of 0.4 to 1.5 mm.

[0007] Preferably, the heating system includes a heating resistance wire, which is uniformly wound around the outermost metal plate of the multi-layer metal furnace core.

[0008] Preferably, the heating resistance wire is tightly fitted with a ceramic protective tube, and the space between the ceramic protective tube and the heating resistance wire is filled with insulating powder.

[0009] Preferably, the power supply system includes a DC power output wire that passes through a helical metal spring, the outer surface of which is covered with a ceramic insulating shell; one end of the transmission rod is connected to the furnace body, and the other end is connected to a drive motor for driving the furnace body to rise and fall.

[0010] Preferably, the furnace body further includes a metal top cover and a metal base; the metal top cover has an air inlet hole connected to the air inlet pipe; the upper surface of the metal base is machined with a guide channel for collecting gas, and the center of the metal base has an air outlet hole connected to the air outlet pipe.

[0011] Preferably, a sensor mounting slot is provided on the back of the metal base, and a thermocouple is embedded in the sensor mounting slot. The probe of the thermocouple is in close contact with the inner wall of the metal base for real-time measurement of the outlet gas temperature and feedback to the control system.

[0012] Preferably, the furnace body is wrapped with an insulation layer, which includes an inner mica board and an outer asbestos fiber felt, and the insulation layer is covered with a stainless steel shell.

[0013] Preferably, the control system includes a PID controller, which receives temperature signals from thermocouple feedback and automatically adjusts the power of the heating system to maintain the set outlet gas temperature.

[0014] Preferably, the metal plate is made of Inconel 600 or Haynes 214; the ceramic spacer is made of alumina or silicon nitride.

[0015] In summary, the present invention has the following beneficial effects: 1. This invention achieves efficient and uniform heating through multi-layer microchannels, with outlet gas temperature uniformity better than ±5℃. The multi-layer metal furnace core consists of 6 to 18 layers of high-temperature resistant metal plates with a thickness of 0.6 to 2 mm stacked in parallel, with ceramic spacers forming uniform fluid channels of 0.4 to 1.5 mm between adjacent plates. Inert gas flows through each layer of channels in a laminar or transitional flow state, fully exchanging heat with the high-temperature metal plates, eliminating the radial temperature gradient of traditional single-tube heaters, and ensuring that the outlet gas temperature uniformity is stably controlled within ±5℃, meeting the stringent process requirements of semiconductor manufacturing, material synthesis, and other fields. 2. This invention features indirect heating and an all-metal furnace core structure, extending the lifespan of the heating element to over 15,000 hours. The heating resistance wire is evenly wound around the outermost metal plate and encased in a ceramic protective tube and insulating powder. The resistance wire does not directly contact the airflow, avoiding high-speed gas erosion and oxidation corrosion. Heat is conducted to the internal channels through multiple metal plates, dispersing localized thermal stress and significantly improving the durability of the heating element. The average service life is extended to over 15,000 hours, reducing maintenance frequency and costs. 3. This invention utilizes closed-loop PID control and close-fitting temperature feedback to achieve precise constant temperature control. A thermocouple is embedded in the back of the metal base, and the probe is in close contact with the inner wall of the base to measure the outlet gas temperature in real time. The signal is fed back to the PID controller to automatically adjust the heating power. This system overcomes thermal inertia and external interference, and can stably maintain any set temperature from 700 to 1300℃. It features high control accuracy, fast response, and ensures stability during long-term operation. 4. This invention features multiple safety protections and an automated lifting design, enhancing operational convenience and system reliability. The power supply wire passes through a spiral metal spring and is wrapped in a ceramic insulating shell, accommodating wire expansion and contraction during furnace lifting and preventing leakage. The furnace body is equipped with a mica board + asbestos fiber felt composite insulation layer and a stainless steel outer shell, reducing heat loss and ensuring surface safety. The drive motor achieves automatic furnace lifting via a transmission rod, facilitating sample loading and maintenance. The overall structure balances safety, energy efficiency, and operational convenience. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a top view schematic diagram of the multi-layer metal furnace core of the present invention; Figure 3 This is a schematic diagram of the heating resistance wire structure of the present invention; Figure 4 This is a top view of the flow channel of the metal base of the present invention; Figure 5 This is a schematic diagram of the metal base sensor mounting slot of the present invention; Figure 6 This is a schematic diagram of the process of the present invention.

[0017] Figure label: 1. Power supply system; 11. Wire; 12. Metal spring; 13. Ceramic insulating shell; 2. Transmission rod; 21. Drive motor; 3. Furnace body; 31. Metal top cover; 311. Air inlet; 32. Multi-layer metal furnace core; 321. Metal plate; 322. Ceramic spacer; 33. Heating resistance wire; 331. Ceramic protective tube; 34. Metal base; 341. Flow guide channel; 342. Air outlet; 343. Sensor mounting slot; 344. Thermocouple; 35. Insulation layer; 36. Outer shell; 4. Inlet pipe; 5. Outlet pipe. Detailed Implementation

[0018] To make the technical means, creative features, achieved objectives, and effects of this invention easier to understand, the invention is further described below with reference to specific embodiments and accompanying drawings. However, the following embodiments are merely preferred embodiments of this invention and not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments described herein without creative effort are all within the protection scope of this invention.

[0019] Specific embodiments of the present invention are described below with reference to the accompanying drawings: Example 1:

[0020] refer to Figures 1-5 The high-temperature furnace system for heating gas includes a furnace body 3, a power supply system 1 and a transmission rod 2. Inside the furnace is a multi-layer metal furnace core 32, which is composed of several layers of parallel stacked high-temperature resistant metal plates 321. Adjacent metal plates 321 are fixed by spacer supports to form fluid channels at the micron to millimeter level. The air inlet pipe 4 and the air outlet pipe 5 are respectively connected to the furnace body 3; The heating system, located on the outside of the multi-layer metal furnace core 32, is used to supply heat to the metal plate 321; Control system, used to control the power of the heating system; In this process, the inert gas flows in laminar or transitional flow within the fluid channel, achieving a temperature uniformity of the outlet gas within ±5℃.

[0021] The multi-layer metal furnace core 32 is composed of 6 to 18 layers of high-temperature resistant metal plates 321 with a thickness of 0.6 to 2 mm stacked in parallel; the spacer support consists of 4 to 8 ceramic spacer columns 322 with a diameter of 1.5 to 3.5 mm and a height of 0.4 to 1.5 mm.

[0022] Specifically, the multi-layer metal furnace core 32 is composed of 6 to 18 layers of high-temperature resistant metal plates 321 with a thickness of 0.6 to 2 mm stacked in parallel, and the spacer support consists of 4 to 8 ceramic spacer columns 322 with a diameter of 1.5 to 3.5 mm and a height of 0.4 to 1.5 mm. The above parameter range optimizes the size and number of fluid channels, enabling sufficient heat exchange of the gas in laminar or transitional flow states. Meanwhile, the ceramic spacer column 322 is high-temperature resistant and insulating. This achieves an optimal balance between gas flow resistance and heating uniformity while ensuring mechanical strength and heat exchange efficiency, adapting to different flow rate and temperature requirements, and extending the furnace core's service life.

[0023] The heating system includes a heating resistance wire 33, which is uniformly wound around the outermost metal plate 321 of the multi-layer metal furnace core 32. A ceramic protective tube 331 is tightly fitted around the heating resistance wire, and insulating powder is filled between the ceramic protective tube 331 and the heating resistance wire 33.

[0024] Specifically, the heating system includes a heating resistance wire 33 evenly wound around the outermost metal plate 321 of the multi-layer metal furnace core 32, and a ceramic protective tube 331 tightly fitted around the resistance wire, with insulating powder filling the space between the ceramic protective tube 331 and the resistance wire. The resistance wire directly heats the outer metal plate 321, and the heat is conducted to each layer through the metal plate 321. The ceramic protective tube 331 isolates the resistance wire from the external environment, and the insulating powder prevents short circuits. This achieves an efficient, safe, and uniform indirect heating method, avoiding oxidation or contamination caused by direct contact between the resistance wire and the gas. The ceramic protective tube 331 and the insulating powder improve electrical safety and high-temperature durability.

[0025] The power supply system 1 includes a DC power output wire 11, which passes through a spiral metal spring 12. The outer surface of the metal spring 12 is covered with a ceramic insulating shell 13. One end of the transmission rod 2 is connected to the furnace body 3, and the other end is connected to the drive motor 21 to drive the furnace body 3 to rise and fall.

[0026] Specifically, the power supply system 1 includes a DC power output wire 11 passing through a helical metal spring 12, the outer surface of which is covered with a ceramic insulating shell 13; one end of the transmission rod 2 is connected to the furnace body 3, and the other end is connected to the drive motor 21 to drive the furnace body 3 to rise and fall. The helical metal spring 12 provides flexible protection and tensile strength for the wire 11, and the ceramic insulating shell 13 prevents high-temperature leakage; the drive motor 21 realizes the automatic rising and falling of the furnace body 3, which facilitates sample loading and maintenance; This improves the reliability and safety of the power supply system 1, adapts to the bending of the wire 11 when the furnace body 3 is raised and lowered, and realizes automated operation, reducing the intensity of manual labor.

[0027] The furnace body 3 also includes a metal top cover 31 and a metal base 34; the metal top cover 31 has an air inlet hole 311 connected to the air inlet pipe 4; the upper surface of the metal base 34 is machined with a guide channel 341 for collecting gas, the center of the metal base 34 has an air outlet hole 342 connected to the air outlet pipe 5, and the back of the metal base 34 has a sensor mounting groove 343, in which a thermocouple 344 is embedded, and the probe of the thermocouple 344 is in close contact with the inner wall of the metal base 34 for real-time measurement of the outlet gas temperature and feedback to the control system.

[0028] Specifically, the furnace body 3 also includes a metal top cover 31 and a metal base 34. The metal top cover 31 has an air inlet hole 311 connected to the air inlet pipe 4. The upper surface of the metal base 34 is machined with a guide channel 341 for collecting gas. The center of the base has an air outlet hole 342 connected to the air outlet pipe 5. The back of the metal base 34 has a sensor mounting groove 343. A thermocouple 344 is embedded in the groove. The thermocouple 344 probe is in close contact with the inner wall of the metal base 34 for real-time measurement of the outlet gas temperature and feedback to the control system. The aforementioned structure allows gas to enter the multi-layer furnace core uniformly from the top. After heating, the gas converges in the base guide channel 341 and exits from the center. Thermocouple 344 directly contacts the inner wall of the base to measure the actual outlet temperature. This optimizes the airflow path, avoids dead zones, improves the accuracy and response speed of temperature measurement, provides reliable feedback for closed-loop control, and further enhances the uniformity of the outlet temperature.

[0029] The furnace body 3 is wrapped with an insulation layer 35 on the outside. The insulation layer 35 includes an inner mica board and an outer asbestos fiber felt. The insulation layer 35 is covered with a stainless steel shell 36.

[0030] Specifically, the furnace body 3 is wrapped with an insulation layer 35, which includes an inner mica board and an outer asbestos fiber felt. The insulation layer 35 is further protected by a stainless steel outer shell 36. The mica board is heat-resistant and insulating, the asbestos fiber felt provides low thermal conductivity, and the stainless steel outer shell 36 protects the insulation layer 35. This significantly reduces heat loss from the furnace body 3, lowers energy consumption, and ensures the temperature safety of the outer shell 36, thereby improving the system's thermal efficiency and operational safety.

[0031] The control system includes a PID controller, which receives the temperature signal from thermocouple 344 and automatically adjusts the power of the heating system to maintain the set outlet gas temperature.

[0032] Specifically, the control system includes a PID controller. The PID controller receives the temperature signal from thermocouple 344 and automatically adjusts the power of the heating system to maintain the set outlet gas temperature. The PID control adjusts the heating power in real time according to the deviation to achieve precise temperature control. This enables closed-loop automatic control of the outlet gas temperature, overcoming external interference and thermal inertia, ensuring long-term operational stability, and meeting high-precision process requirements.

[0033] The metal plate 321 is made of Inconel 600 or Haynes 214; the ceramic spacer 322 is made of alumina or silicon nitride.

[0034] Specifically, the metal plate 321 is made of Inconel 600 or Haynes 214, and the ceramic spacer 322 is made of alumina or silicon nitride. These materials possess excellent high-temperature strength, oxidation resistance, and thermal shock resistance, and are chemically compatible with inert gases. This ensures that the furnace core remains undeformed and unoxidized during long-term operation at temperatures above 800°C, and that the ceramic spacer 322 maintains insulation and dimensional stability, significantly improving the system's reliability and service life in ultra-high temperature environments.

[0035] Working principle of this embodiment: First, before starting the system, the furnace body 3 needs to be raised to the working position via the transmission rod 2. The drive motor 21 (stepper or servo motor) drives the transmission rod 2 to move vertically, allowing the furnace body 3 to move as a whole, facilitating sample loading and maintenance. The power supply system 1 of the furnace body 3 uses a DC power supply, with the output wire 11 passing through a spiral metal spring 12. The outer surface of the metal spring 12 is wrapped with a ceramic insulating shell 36. The spring expands and contracts with the wire 11 when the furnace body 3 is raised and lowered, preventing the wire 11 from getting tangled or bent. At the same time, the ceramic shell 36 isolates high-temperature leakage.

[0036] The core component inside the furnace body 3 is a multi-layer metal furnace core 32, which is composed of 6 to 18 layers of high-temperature resistant metal plates 321 (Inconel 600 or Haynes 214) with a thickness of 0.6 to 2 mm stacked in parallel. Adjacent metal plates 321 are supported and fixed by 4 to 8 precision ceramic spacers 322 (alumina or silicon nitride) with a diameter of 1.5 to 3.5 mm and a height of 0.4 to 1.5 mm, forming uniform micron to millimeter-level gap channels. Heating resistance wires 33 (Kanthal A-1 or MoSi2) are uniformly wound around the outermost metal plate 321 of the furnace core. Each resistance wire is tightly wrapped with an alumina ceramic protective tube 331, which is filled with high-purity alumina insulating powder. The Joule heat generated when the resistance wire is energized first heats the outermost metal plate 321 through radiation and conduction. The heat is then transferred layer by layer inward to all metal plates 321, so that the temperature field of the entire multi-layer furnace core remains highly uniform.

[0037] Once the system reaches the preset temperature, inert gas (such as argon, nitrogen, or helium) enters the inlet 311 of the metal top cover 31 of the furnace body 3 from the inlet pipe 4 at a flow rate of 0.4 to 70 liters per minute. The gas then flows into the gap channels of each layer of the multi-layer metal furnace core 32. Because the channel height is only 0.4 to 1.5 millimeters, the gas is forced to flow in a laminar or transitional flow state. When flowing through each channel, the gas comes into full contact with the surfaces of the upper and lower high-temperature metal plates 321, resulting in an effective heat exchange area much larger than that of a traditional single-tube structure, and a significant improvement in heat exchange efficiency. The fluid boundary layer of the laminar flow within the micro-channels is extremely thin, eliminating the radial temperature gradient between the center and edge of the large-diameter pipe, allowing the gas to be uniformly heated during the flow process.

[0038] The heated high-temperature gas flows out from the outlets of each channel and enters the radial guide channels 341 machined on the upper surface of the metal base 34. The guide channels 341 converge the gas from multiple layers to the outlet 342 in the center of the base, ensuring that the airflow is fully mixed before being output through the outlet pipe 5. Thermocouple 344 (K-type or S-type) probes embedded in the back of the base are in close contact with the inner wall of the base to measure the actual temperature of the outlet gas in real time and feed the signal back to the PID controller. The PID controller automatically adjusts the power supply of the heating resistance wire 33 according to the deviation between the set value and the measured value to achieve closed-loop constant temperature control.

[0039] Throughout the process, the insulation layer 35 (inner mica board, outer asbestos fiber felt) on the outside of the furnace body 3 effectively reduces heat loss, while the stainless steel outer shell 36 ensures a safe surface temperature. Since the heating resistance wire 33 does not come into direct contact with the airflow, and the heat capacity and heat conduction of the multi-layer metal plate 321 disperse local thermal stress, premature failure of the resistance wire due to high-speed airflow scouring or local overheating is avoided. At the same time, the uniform temperature field also inhibits the oxidation and creep of the metal plate 321, extending the average service life of the heating element to more than 15,000 hours.

[0040] Ultimately, the temperature of the inert gas flowing out of the outlet pipe 5 can be stably controlled at any set point between 700 and 1300℃, with an outlet temperature uniformity better than ±5℃, meeting the stringent process requirements of semiconductor manufacturing, material synthesis, and other fields. The system can also lower the furnace body 3 via the drive motor 21 for easy replacement of the furnace core or maintenance. Example 2:

[0041] This embodiment is basically the same as embodiment 1, except that: the metal multilayer furnace core 32 (32) adopts 8 layers of Inconel 600 metal plates 321 with a thickness of 1.5mm, and the ceramic spacer column 322 (322) has a height of 1.2mm; the heating resistance wire 33 (33) adopts MoSi2 wire with a maximum heating power of 15kW, which is used to heat nitrogen (N2) to 1200℃, and the outlet temperature uniformity can still be maintained within ±5℃.

[0042] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-temperature furnace system for heating gas, characterized in that: It includes a furnace body (3), a power supply system (1) and a transmission rod (2), and is equipped with a multi-layer metal furnace core (32) inside. The multi-layer metal furnace core (32) is composed of several layers of parallel stacked high-temperature resistant metal plates (321). Adjacent metal plates (321) are fixed by spacer support members to form a fluid channel at the micron to millimeter level. The air inlet pipe (4) and the air outlet pipe (5) are respectively connected to the furnace body (3); A heating system, located on the outside of the multi-layer metal furnace core (32), is used to supply heat to the metal plate (321); Control system, used to control the power of the heating system; The inert gas flows in laminar or transitional flow within the fluid channel, achieving a uniform outlet gas temperature within ±5℃.

2. The high-temperature furnace system for heating gas according to claim 1, characterized in that: The multi-layer metal furnace core (32) is made of 6 to 18 layers of high-temperature resistant metal plates (321) with a thickness of 0.6 to 2 mm stacked in parallel; the spacer support is 4 to 8 ceramic spacer columns (322) with a diameter of 1.5 to 3.5 mm and a height of 0.4 to 1.5 mm.

3. The high-temperature furnace system for heating gas according to claim 1, characterized in that: The heating system includes a heating resistance wire (33), which is uniformly wound around the outermost metal plate (321) of the multi-layer metal furnace core (32).

4. The high-temperature furnace system for heating gas according to claim 3, characterized in that: The heating resistance wire (33) is tightly fitted with a ceramic protective tube (331), and insulating powder is filled between the ceramic protective tube (331) and the heating resistance wire (33).

5. The high-temperature furnace system for heating gas according to claim 1, characterized in that: The power supply system (1) includes a DC power output wire (11), which passes through a spiral metal spring (12), and the outer surface of the metal spring (12) is covered with a ceramic insulating shell (13); one end of the transmission rod (2) is connected to the furnace body (3), and the other end is connected to the drive motor (21) for driving the furnace body (3) to rise and fall.

6. The high-temperature furnace system for heating gas according to claim 1, characterized in that: The furnace body (3) also includes a metal top cover (31) and a metal base (34); the metal top cover (31) is provided with an air inlet hole (311) connected to the air inlet pipe (4); the upper surface of the metal base (34) is machined with a guide channel (341) for gathering gas, and the center of the metal base (34) is provided with an air outlet hole (342) connected to the air outlet pipe (5).

7. The high-temperature furnace system for heating gas according to claim 6, characterized in that: The back of the metal base (34) is provided with a sensor mounting slot (343), in which a thermocouple (344) is embedded. The probe of the thermocouple (344) is in close contact with the inner wall of the metal base (34) for real-time measurement of the outlet gas temperature and feedback to the control system.

8. The high-temperature furnace system for heating gas according to claim 1, characterized in that: The furnace body (3) is wrapped with an insulation layer (35) on the outside. The insulation layer (35) includes an inner mica board (351) and an outer asbestos fiber felt (352). The insulation layer (35) is provided with a stainless steel shell (36).

9. The high-temperature furnace system for heating gas according to claim 1, characterized in that: The control system includes a PID controller, which receives temperature signals from thermocouples (344) and automatically adjusts the power of the heating system to maintain the set outlet gas temperature.

10. The high-temperature furnace system for heating gas according to claim 1, characterized in that: The metal plate (321) is made of Inconel 600 or Haynes 214; the ceramic spacer (322) is made of alumina or silicon nitride.

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