Can a timed experimental tube furnace be evacuated?

The timed experimental tube furnace can be evacuated, but it needs to be customized according to specific application scenarios and equipment configurations. The following analysis will be conducted from four aspects: technical feasibility, vacuum system configuration, application scenarios, and precautions:

1. Technical feasibility: Compatibility between vacuum system and tube furnace
Vacuum degree requirement matching
Basic vacuum: Conventional experimental tube furnaces can achieve a vacuum degree of 10 ⁻ ² to 10 ⁻ ³ Pa, suitable for most experiments such as metal heat treatment and ceramic sintering.
High vacuum requirement: If a pressure below 10 ⁻⁴ Pa is required (such as in semiconductor material preparation), a customized combination system of turbo molecular pump and diffusion pump is needed, and a fully metal sealed structure is adopted.
Furnace structure adaptation
Sealing design: Metal sealing rings (such as oxygen free copper gaskets) or blade flanges are used to prevent rubber sealing rings from aging and leaking at high temperatures.
Material pressure resistance: The furnace tube material needs to withstand the internal and external pressure difference under vacuum environment (such as quartz furnace tube ≤ 0.1MPa, corundum furnace tube ≤ 0.2MPa).

2. Vacuum system configuration: key components and functions
Vacuum pump: Extract gas from the furnace and establish a vacuum environment with rotary vane pump (coarse vacuum, ≤ 10 ⁻¹ Pa) and molecular pump (high vacuum, ≤ 10 ⁻⁴ Pa).
Vacuum gauge: Real time monitoring of the vacuum level inside the furnace, resistance gauge (coarse vacuum), ionization gauge (high vacuum).
Vacuum valve: controls the opening and closing of the air circuit to prevent oil vapor from flowing back, all metal angle valve, electromagnetic baffle valve.
Cold trap/catcher: adsorbs volatile substances, protects vacuum pump, liquid nitrogen cold trap (low-temperature adsorption), molecular sieve catcher (room temperature adsorption).
Air release valve: After the experiment is completed, balance the air pressure inside and outside the furnace to prevent the furnace tube from breaking. It is manually/automatically controlled and equipped with a pressure sensor.

3. Application scenario: Typical experiments in a vacuum environment
Vacuum sintering
Purpose: To remove gas impurities from powder samples and promote densification.
Case: Hard alloy (WC Co) was sintered at 1500 ℃ under a vacuum of 10 ⁻ Pa, and the porosity decreased to below 0.5%.
annealing
Purpose: To eliminate internal stress in materials and improve organizational structure.
Case: Titanium alloy annealed at 800 ℃ under a vacuum of 10 ⁻ Pa showed a 15% increase in hardness and a 20% increase in toughness.
vacuum brazing
Purpose: To achieve high-strength connection in a non oxidizing environment.
Case: Aircraft engine blades were brazed at 1150 ℃ under a vacuum of 10 ⁻ Pa, and the joint strength reached over 90% of the base material.
Vapor deposition
Purpose: To deposit thin films or coatings in a vacuum environment.
Case: Silicon carbide coating was deposited by CVD at 1600 ℃ under a vacuum of 10 ⁻⁴ Pa, with a thickness uniformity of ± 5%.

4. Customization precautions: Ensure the reliability and safety of the vacuum system
Clarify experimental requirements
Vacuum degree: Select the appropriate vacuum degree based on the material characteristics (such as metal heat treatment ≤ 10 ⁻ ² Pa, semiconductor process ≤ 10 ⁻⁵ Pa).
Extraction rate: Calculate the furnace volume and leakage rate to determine the pumping speed of the pump (e.g. a 100L furnace requires ≥ 50L/s rotary vane pump).
Anti pollution design
Oil vapor protection: A cold trap should be installed before the pump in the high vacuum system to prevent oil vapor from contaminating the sample.
Material deflation: Select low deflation rate materials (such as 304 stainless steel furnace body), and perform a 200 ℃ baking degassing before the experiment.
Safety interlock
Pressure protection: When the vacuum degree is abnormal (such as ≥ 10 ⁻¹ Pa), the heating power supply will be automatically cut off and an alarm will be triggered.
Cooling water monitoring: The vacuum pump needs to be equipped with a water flow switch to stop the machine when the water is cut off to prevent overheating and damage.
Operating specifications
Pre vacuuming: Before heating, the vacuum degree should be evacuated to ≤ 10 ⁻¹ Pa to avoid material oxidation at high temperatures.
Inflatable protection: After cooling to ≤ 200 ℃, inert gas is introduced to break the vacuum and prevent thermal stress cracking of the furnace tube.

5. Summary and Suggestions
The timed experimental tube furnace can achieve vacuum function, but the vacuum system needs to be customized according to experimental requirements:
Clearly define the vacuum degree and pumping rate, and select the matching vacuum pump and valve.
Emphasize pollution prevention and safety design to ensure sample purity and equipment reliability.
Choose professional suppliers and prioritize manufacturers with experience and successful cases in vacuum system integration.
By reasonable customization, the tube furnace can operate stably in a vacuum environment, providing critical support for high-temperature experiments and significantly improving material properties and experimental repeatability.