Can bimetallic thermometers be used outdoors or in corrosive environments?

In industrial sites or outdoor equipment, temperature monitoring is a key link to ensure operational safety and product quality. Bimetallic thermometers are a mechanical temperature measurement tool that does not require power, has a simple structure, and has intuitive readings. They are widely used in petroleum, chemical, metallurgy, water treatment, and heating systems.

1. Brief description of the principle of bimetallic thermometers

The bimetallic thermometer is composed of two metal sheets with different thermal expansion coefficients. As the temperature changes, the metal sheets deform, thereby driving the pointer to move and realizing a mechanical indication of the temperature. Because it does not require electricity and has a sturdy structure, it is suitable for use in environments where power supply is inconvenient or unstable, and is a commonly used temperature measurement tool in traditional industrial fields.

2. Challenges of outdoor environments

In outdoor environments, thermometers face the following problems:
Wind, rain, and ultraviolet radiation: long-term exposure may cause aging of the shell and blurred scales;
High humidity, condensation or frost: may affect temperature response or damage components;
Severe changes in temperature difference: frequent alternation of hot and cold may cause parts to loosen or seals to fail.
Therefore, bimetallic thermometers made of ordinary materials may have a shortened lifespan or inaccurate readings when used outdoors.

3. Hidden dangers of corrosive environments

In chemical plants, sewage treatment plants, acid and alkali workshops and other environments, the air may contain corrosive gases (such as H₂S, chlorine, acid mist, etc.). If the thermometer housing, probe or connecting parts do not have anti-corrosion properties, they will be corroded quickly, resulting in:
Rust or cracking of the case;
Stuck reading mechanism;
Broken or failed probe.
This not only affects the temperature measurement accuracy, but may also bring safety hazards to the equipment.

4. How to choose a corrosion-resistant bimetallic thermometer?

In order to ensure that the bimetallic thermometer can work stably for a long time in harsh environments, it is recommended to pay attention to the following points when selecting:

1. Choose a stainless steel housing and probe

304, 316 or 316L stainless steel is especially recommended, which has excellent corrosion resistance and is suitable for most acid and alkali neutral media.

2. Choose a head structure with a protection level

For example, IP65/IP67 protection level can prevent rain and dust from intrusion.

3. Install a corrosion-resistant thermowell (Thermowell)

For high-corrosion, high-pressure or high-temperature applications, it is recommended to install a thermowell to protect the probe and facilitate replacement and maintenance.

4. Choose an anti-UV or anti-fog mask for the dial

Some products are equipped with an anti-UV transparent cover or anti-fogging glass to prevent blurred readings.
Bimetallic thermometers can be used outdoors or in corrosive environments, but products with anti-corrosion designs must be selected.
Correct selection not only extends the service life of the equipment, but also ensures the safety and accuracy of on-site temperature measurement. For working conditions with variable usage scenarios or high requirements, it is recommended to communicate with suppliers for customized solutions, such as material upgrades, interface reinforcement, explosion-proof design, etc.