In the field of industrial temperature measurement, platinum resistance temperature sensors are widely used due to their high accuracy and stability. Fixed flange-type probe platinum resistance sensors and surface-mounted gasket-type platinum resistance sensors are two common types, exhibiting significant differences in structure, installation method, application scenarios, and performance. This article will provide a detailed comparison of these two sensors from multiple dimensions to help users make informed choices based on their actual needs.
Structural and Installation Differences
Fixed flange-type probe platinum resistance sensors utilize a flange connection structure, rigidly fixing the sensor flange to a standard flange (such as DN25PN1.6) on the pipe or equipment using bolts. Its mounting surface is flat and requires a sealing gasket for media isolation, making it suitable for high-pressure, high-temperature, and high-vibration environments. Structurally, it typically features an integral metal casing, with the hot end extending into the medium and the cold end providing a junction box. It boasts high overall rigidity and strong resistance to deformation. During installation, ensure the flange surfaces are parallel and undamaged, use a high-temperature graphite gasket, and tighten the bolts evenly diagonally to avoid uneven loading. After installation, test the sealing to prevent leakage.
Surface-mounted gasket-type platinum resistance sensors are directly fixed to the object surface using a gasket (patch-type), typically installed with screws or adhesive. Its structure is compact and does not require insertion into the measured medium, making it suitable for surface temperature measurement. During installation, clean the mounting surface of impurities, apply thermal conductive grease to improve heat transfer, and tighten the torque to 15-20 N·m to prevent thread stripping. In vibrating environments, anti-loosening washers can be added. This installation method is simple, does not damage the structure of the measured object, and is suitable for quick disassembly and replacement.
Applicable Scenarios and Industry Applications
Fixed flange-type probe platinum resistance sensors are suitable for high-pressure systems (≥1.6MPa), high-temperature environments (-200℃~850℃), and high-vibration applications, such as in the petrochemical, nuclear power, metallurgy, and thermal power boiler industries. They have strong vibration resistance and good sealing, making them suitable for long-term fixed installation with low maintenance frequency, but disassembly is complex.
Surface-mounted gasket-type platinum resistance thermometers are suitable for medium and low-pressure environments (≤1.6MPa) and for temperature measurement on conventional industrial pipelines and object surfaces, such as in mechanical manufacturing, food and pharmaceutical industries, HVAC, and power auxiliary equipment. They are easy to install, do not damage the structure of the object being measured, and are suitable for periodic calibration or replacement, although they require frequent maintenance. However, anti-loosening designs are necessary under prolonged high vibration conditions.
Performance Parameters and Selection Considerations
Accuracy Class: Both comply with the IEC 60751 standard, commonly available in Class A (±0.15℃) and Class B (±0.30℃), with no essential difference.
Thermal Response Time: Fixed flange type is slightly slower due to the thermal inertia of the flange (10s~40s), while the surface-mounted type responds faster (3s~10s), suitable for applications requiring rapid temperature feedback.
Protection Class: The protection class of the fixed flange type depends on the flange sealing design, often custom-engineered; the surface-mounted type is widely available, commonly IP65~IP68, supporting corrosion resistance (316L stainless steel) and explosion protection (Ex d IIC T6).
Wiring Method: Both support three-wire (mainstream in industry) and four-wire (high-precision laboratory) configurations; two-wire is only suitable for high-resistance models such as PT1000.
Selection Suggestions and Precautions
Choose Fixed Flange Type: When temperature measurement is required inside pipes or containers, and the environment is harsh (high pressure, high temperature, strong vibration), the fixed flange type is the preferred choice. It has excellent vibration resistance and sealing performance, suitable for long-term fixed installation.
Choose Surface-Mounted Type: When only the surface temperature of an object needs to be measured, and installation space is limited or quick removal is required, the surface-mounted type is more suitable. It is easy to install, does not damage the structure of the object being measured, and is suitable for periodic calibration or replacement.
Precautions:
Fixed Flange Type: Ensure that the flange specifications match, and align the flange surfaces during installation to avoid uneven loading.
Surface-Mounted Type: Ensure that the mounting surface is flat and smooth, and use thermal conductive grease to reduce contact thermal resistance.
Summary
Fixed flange type probe platinum resistance thermometers and surface-mounted gasket-type platinum resistance thermometers each have their own characteristics in terms of structure, installation method, application scenarios, and performance. Fixed flange type sensors are suitable for high-pressure, high-temperature, and strong vibration environments, offering strong vibration resistance and good sealing performance; surface-mounted sensors are suitable for medium and low-pressure applications and surface temperature measurement, offering easy installation and fast response speed. Users should select the most suitable sensor type based on their actual needs, such as the temperature measurement location (internal or surface), environmental conditions (pressure, temperature, vibration), and maintenance frequency. Proper selection ensures the accuracy and reliability of temperature measurement, providing strong support for industrial process control. (AI generated)
