Small tube furnace for laboratory use

The small tube furnace used in the laboratory is a key equipment for material heat treatment, chemical analysis, and scientific research teaching. When selecting, attention should be paid to the following aspects:

1. Core parameters
Temperature range and temperature control accuracy
Maximum temperature: Select according to experimental requirements. The temperature range of common laboratory tube furnaces is 1000 ℃ -1700 ℃. For example, metal oxidation experiments typically require 1000 ℃ -1200 ℃, while ceramic sintering may require 1400 ℃ -1600 ℃.
Temperature control accuracy: Priority should be given to equipment within ± 1 ℃ to ensure the reproducibility of experimental results. The PID intelligent temperature control system can effectively reduce temperature fluctuations.
Heating rate: Depending on the thermal shock resistance of the material, rapid heating (such as 10 ℃/min) is suitable for heat-resistant materials, while slow heating (such as 5 ℃/min) can reduce thermal stress.
Furnace tube material and size
Material:
Quartz tube: resistant to high temperatures (below 1100 ℃), transparent and easy to observe, but prone to react with strong alkalis, suitable for oxidizing atmospheres.
Corundum tube (alumina): high temperature resistance (above 1600 ℃), good chemical stability, suitable for acidic or alkaline atmospheres.
Metal tubes (stainless steel, molybdenum): suitable for reducing atmospheres (such as hydrogen), but may deform at high temperatures.
Size:
Inner diameter: Select according to the sample size, commonly ranging from 20mm to 100mm. It is necessary to ensure that the sample can be smoothly inserted and leave space for gas circulation.
Length: The laboratory commonly uses 300mm-1200mm, and space needs to be reserved for placing crucibles or brackets.
Atmosphere control ability
Vacuum function: If an anaerobic environment is required, choose a tube furnace with a mechanical pump (vacuum degree can reach 10 ⁻ Pa).
Gas inlet: Supports the inlet of inert gases (nitrogen, argon) or reducing gases (hydrogen), and requires flow meters and gas purification devices.
Sealing: Flange connection or O-ring sealing design to prevent gas leakage. For example, when hydrogen is introduced, a tube furnace with good sealing and explosion-proof performance should be selected.

2. Functional and safety design
Operational convenience
Program temperature control: supports multiple heating programs (such as heating insulation cooling), and can store commonly used process curves.
Data recording: Built in or external data acquisition system to record temperature time curves.
Observation window: Quartz tube furnaces can be equipped with observation windows to monitor the status of samples in real time.
Operation interface: Modern operation methods such as touch screen mode are more popular among users, which can intuitively display parameters such as temperature curve and gas flow rate, and support data storage and export.
safety protection
Overtemperature alarm: Automatically shuts off when the temperature exceeds the set value.
Leakage protection: prevent the risk of electric shock.
Gas leak detection: When flammable gases such as hydrogen are introduced, sensors must be equipped.
Emergency stop: One click stop of heating and gas supply.
Protection design: Protective covers are added at both ends of the furnace tube, and a quick opening flange design is adopted to prevent the risk of furnace tube explosion.

3. Experimental requirement matching
Material Type
Metal: Requires reducing atmosphere (hydrogen) or vacuum to prevent oxidation.
Ceramic: High temperature corundum tube, supporting oxidizing atmosphere.
Semiconductor: high vacuum+inert gas to avoid impurity contamination.
Batch and Size
Small batch: Choose short furnace tubes (300mm-600mm) to save space.
Long samples: require furnace tubes of over 1000mm or segmented processing.
Sample size: The inner diameter of the furnace tube should be 10-20mm larger than the sample to avoid cracking caused by thermal stress concentration.
scalability
Modular design: supports subsequent upgrades of vacuum pumps and gas purification devices.
Interface compatibility: Reserved thermocouple and pressure sensor interfaces.

4. Operation and maintenance suggestions
Pre use inspection
Confirm that there are no cracks in the furnace tube and the sealing ring is intact.
Test the gas inlet and vacuum pump function.
Heat up to the highest temperature without load and check the temperature control accuracy.
routine maintenance
Regularly clean the oxide inside the furnace to prevent short circuits.
Apply high-temperature grease when replacing the sealing ring.
Avoid frequent rapid cooling and heating to extend the lifespan of the furnace tube.
Safety Specifications
When hydrogen gas is introduced, it should be kept away from the fire source and equipped with an exhaust system.
Wear protective gloves and goggles during operation.
After the experiment is completed, turn off the gas first, then cool down to below 100 ℃, and then turn off the power.

5. Typical application scenarios and selection cases
Preparation of metal oxides: 1200 ℃, quartz tube, air atmosphere, programmed temperature control
Ceramic sintering: 1600 ℃, corundum tube, nitrogen protection, multi-stage heating
CVD coating: 1000 ℃, quartz tube, hydrogen/methane mixed gas, vacuum pretreatment
Material annealing: 800 ℃, stainless steel tube, argon protection, slow cooling