Temperature is a crucial parameter in both production and daily life. In industrial production, such as manufacturing, pharmaceuticals, food processing, electronics, and automotive industries, temperature measurement is critical for ensuring production efficiency and safety.

In the process of measuring the temperature of gases, liquids, and steam, high accuracy and timely response are usually required. Therefore, when selecting temperature instruments, attention must be paid to their accuracy, resolution, and the diameter of the temperature sensing probe. In certain special industrial environments that are flammable, explosive, or corrosive, temperature instruments must not only provide accurate measurements but also be safe and durable. In these cases, material selection is particularly important.

Moreover, different industrial applications require different types of temperature sensors. The most commonly used sensors, classified by working principle, include thermocouples, resistance temperature detectors (RTDs), and bimetallic thermometers.

· Thermocouples measure temperature based on the voltage generated at the junction of two different metals. They are simple in structure, resistant to high temperatures, respond quickly, and are suitable for harsh environments. They have a wide high-temperature measurement range (from tens to over a thousand degrees Celsius) but are less accurate at low temperatures compared to RTDs. Typical applications include high-temperature industrial processes such as steelmaking furnaces, steam pipelines, blast furnaces (hearth temperature 1400~1500℃, hot blast temperature 1200~1300℃), and converter steelmaking (molten pool temperature 1600~1700℃). Using thermocouples ensures that the temperatures of molten iron and steel meet process requirements, improving steel strength, toughness, and other properties.

· Resistance Temperature Detectors (RTDs) measure temperature based on the change in metal resistance with temperature. They are highly accurate (±0.1~0.5℃), have good linearity and stability, and respond at moderate speed. Their temperature range generally spans -200~500℃, and they require a supporting circuit to convert resistance changes into electrical signals or digital outputs. RTDs are mainly used for precise medium- and low-temperature measurements, such as pharmaceutical reaction vessels, food sterilization, and electronic component aging tests. For example, capacitors and resistors are often subjected to aging tests in high-temperature environments (85℃ or 125℃) for 1000~5000 hours, with temperature fluctuations ≤ ±0.5℃, to assess component lifespan and stability. Using RTDs helps screen out defective components and improve the reliability of end products such as smartphones and computers.

· Bimetallic thermometers operate by the expansion and contraction of two metals with different thermal expansion coefficients, which drives a pointer to display temperature. They are simple in structure, do not require a power source, and allow for direct on-site reading. Their accuracy is lower (±1~3℃) and response slower, making them suitable for on-site indication or mechanical equipment. The typical temperature range is -50~400℃. Bimetallic thermometers are commonly used for medium- and low-temperature measurements, such as machine tool lubrication systems, air compressor cooling systems, and high-temperature workshops. For example, in high-temperature workshops (such as welding workshops with ambient temperatures of 30~45℃), bimetallic thermometers can monitor the temperature at ventilation outlets (below 35℃) to ensure cooling efficiency. In dusty or smoky workshop environments, they provide an intuitive display of ventilation performance, allowing timely adjustment of fan speed to ensure safe working conditions.

To meet the diverse industrial temperature measurement needs, Yichang Zhaofeng Instrument Co., Ltd. offers comprehensive solutions. We produce a wide range of temperature measuring and controlling instruments, including WSS bimetallic thermometers, WTYK(B) explosion-proof capillary temperature controllers, WDXK(B) intelligent explosion-proof digital temperature controllers, and ZF series RTDs/thermocouples. These products are widely applicable across industrial scenarios, meeting the requirements for accuracy, safety, and reliability.