How to choose a tube furnace for university laboratories?

When selecting a tube furnace for university laboratories, multiple key factors need to be considered to ensure that the selected equipment can meet experimental requirements and has good performance and reliability. Here are some specific selection suggestions:

1. Clearly define the temperature requirements for use
Different experiments have different temperature requirements. For example, the drying experiment of biological samples may only require 50-80 ℃, while the melting of high-performance metal alloys may require high temperatures above 1800 ℃.

Suggestion for selection: Firstly, determine the maximum temperature and continuous operating temperature required for the experiment. In order to ensure the smooth progress of the experiment and cope with possible temperature fluctuations, it is recommended to choose a tube furnace with a maximum temperature 100-150 ℃ higher than the required temperature for the experiment. Meanwhile, pay attention to the type and temperature range of heating elements. Common heating elements and their applicable temperatures are as follows:
Molybdenum containing resistance wire: suitable for temperatures below 1200 ℃.
Silicon carbon rod: suitable for temperatures below 1400 ℃.
MoSi ₂ heating element: suitable for temperatures up to around 1700 ℃.

2. Determine the length of the temperature zone
The length of the temperature zone determines the size of the area where the sample can be uniformly heated.
Suggestion for selection: Choose the appropriate temperature zone length based on the size and shape of the experimental sample. For long strips or large-sized samples that require uniform heating, a longer temperature range should be selected. For small chips or trace samples, a shorter temperature range is sufficient to meet the requirements. At the same time, pay attention to distinguishing between the total heating zone length and the constant temperature zone length. The constant temperature zone length should be able to cover the sample area to ensure temperature uniformity.

3. Choose appropriate pipe diameter and furnace size
The pipe diameter and furnace size need to be determined based on the size and quantity of the experimental samples.
Suggestion for selection:
Pipe diameter: If a larger reaction tube is used in the experiment or a larger sample volume needs to be processed, a tube furnace with a larger pipe diameter should be selected. For trace samples, a large pipe diameter is not conducive to heat concentration and stable temperature control.
Furnace size: When handling larger samples or multiple samples simultaneously, a larger furnace space is required.

4. Consider the structural types of tube furnaces
Tube furnaces have two main structures: horizontal and vertical, each with its own advantages and disadvantages.
Suggestion for selection:
Horizontal tube furnace: easy to operate, convenient for placing and removing samples, suitable for most routine experiments, such as sintering of powder materials.
Vertical tube furnace: It has advantages in some special experiments, such as crystal epitaxial growth experiments, which can use gravity to make the reaction gas more evenly distributed on the crystal surface.

5. Do you need vacuum and atmosphere protection
The preparation and processing of many materials require vacuum or specific atmospheric environments.
Suggestion for selection: If the experiment has high environmental requirements, such as avoiding oxidation when synthesizing high-purity metal materials, or if the experiment involves flammable and explosive gases, a tube furnace with vacuum and atmosphere protection functions should be selected.

6. Other considerations
Heating rate: If the experiment has high requirements for heating rate, a tube furnace with rapid annealing function should be selected.
Temperature control accuracy: For experiments that require high-precision temperature control such as precision alloy processing, a tube furnace with high temperature control accuracy should be selected.
Cooling method: A fast and effective cooling method can shorten the working cycle. Water cooling is usually faster than air cooling, but laboratory conditions need to be considered.
Automation level: If frequent operation of the same process is required, choosing a tube furnace with automation control function can improve work efficiency and accuracy.
Safety: Ensure that the tube furnace is equipped with safety devices such as over temperature protection, vacuum monitoring, and pressure protection.
Brand and after-sales service: Choosing products from well-known brands usually ensures better quality and performance. Meanwhile, good after-sales service can provide timely technical support and maintenance in case of equipment problems.

7. Summary
When selecting a tube furnace, university laboratories should comprehensively consider multiple factors such as usage temperature, temperature zone length, pipe diameter and furnace size, structural type, vacuum and atmosphere protection requirements, heating rate, temperature control accuracy, cooling method, automation level, safety, as well as brand and after-sales service.

By carefully evaluating these factors and fully communicating with suppliers, it can be ensured that the selected tube furnace can meet the specific needs of the laboratory and provide strong support for scientific research work.