Structural Essence and Installation Mechanism Comparison
Fixed Flange Mounting Type: The probe end is welded or integrally formed with a rigid metal flange (such as a slip-on or weld-neck flange), and secured to the equipment flange interface with bolts, allowing for penetration into the medium. This forms a rigid, sealed, and non-adjustable installation structure.
Clamp-on Type: The probe is embedded in an elastic metal clamp ring, and the clamp bolt is tightened to make the probe conform to the outer surface of the pipe. This is a non-invasive, non-sealed, and non-adjustable surface contact type installation that does not require drilling holes. Adjustable Threaded Mounting Type: The outer wall of the probe protection tube is machined with standard external threads (such as M27×2, G3/4″), and installation is achieved by screwing it into the threaded interface reserved on the equipment. The insertion depth is adjustable, and some models support a replaceable sleeve design. This is an adjustable, medium-seal, non-penetrating insertion type installation.
Core Performance Parameter Three-Way Comparison
|
Performance Dimension |
Fixed Flange Mounting Type |
Clamp Type |
Adjustable Threaded Mounting Type |
|
Installation Method |
Rigid connection with flange bolts, penetrating the medium |
Clamp tightens the outer wall, surface contact |
Threaded screw-in interface, adjustable insertion depth |
|
Temperature Measurement Location |
Inside the medium (steam, liquid, gas) |
On the outer surface of the equipment |
Inside the medium or near the wall (depending on insertion depth) |
|
Temperature Range |
0℃ to 1300℃+ (S/B/K type) |
≤760℃ (limited by clamp material) |
0℃ to 1300℃+ (matches the probe type) |
|
Thermal Response Time |
60–90 seconds |
≤1–10 seconds |
10–30 seconds (between the two, affected by insertion depth) |
|
Sealing Capability |
High sealing, resistant to PN40+ pressure, compliant with ASME B31.1 |
No sealing function |
Medium sealing, relies on thread fit + sealing gasket, suitable for medium and low pressure (≤PN16) |
|
Vibration Resistance |
Very high (rigid connection) |
Medium (easy to loosen) |
Higher (threaded locking, better impact resistance than clamp) |
|
Maintenance Convenience |
Disassembly requires shutdown, loosening multiple bolts, high replacement cost |
Quick online replacement, no shutdown required |
Probe can be replaced online, sleeve can be retained, convenient maintenance |
|
Calibratable |
Removable for inspection, supports separate calibration |
Not removable, entire unit replacement |
Partially removable, supports separate probe calibration |
|
Standard Basis |
GB/T 30429-2013, GB/T 9119-2010 No national standard, manufacturer-defined according to IEC 60584-1 GB/T 30429-2013 (Assembled Thermocouple), JB/T 8622-1997 (Threaded Connection) |
Application Scenarios and Selection Logic
Fixed Flange Type:
Suitable for temperature measurement inside high-pressure, high-temperature, and highly corrosive media: such as nuclear power main steam pipelines, hydrogenation reactors, refinery plant outlets, and large boiler flues;
Used for safety interlocks, mandatory calibration, and long-term continuous operation, requiring zero leakage and high reliability.
Hose Clamp Type:
Specifically used for external wall temperature measurement where drilling and welding are prohibited and quick inspection is required: such as injection molding machine screws, extruder barrels, heat treatment furnace rollers, water pipe outer walls, and lithium battery electrode pressing rollers;
Suitable for temporary monitoring, process temperature difference analysis, and multi-point deployment, requiring fast response and non-destructive installation.
Adjustable Threaded Type:
Suitable for pipeline temperature measurement in medium and low pressure environments, requiring precise control of insertion depth and high maintainability: such as chemical reactor side walls, pharmaceutical CIP pipelines, water treatment pipelines, and steam tracing pipes;
Used in scenarios requiring periodic calibration, probe replacement, and avoiding overall disassembly, balancing sealing performance and flexibility.
Selection Rhyme:
"For high-pressure media requiring penetration, choose flange; for quick external wall measurement without drilling, use hose clamp; for medium pressure, adjustable and maintainable applications, choose threaded." Consequences of Incorrect Selection:
Using a clamp-type sensor on high-pressure steam pipes → Temperature measurement failure, no seal, leakage risk;
Using a fixed flange on an injection molding machine screw → Damages equipment structure, doubles costs, impossible to maintain;
Using a movable threaded connection in an ultra-high pressure environment → Thread seal failure, media leakage, safety hazard.
Installation and Operation Guidelines
Fixed Flange Type:
Align the flange faces before installation, parallelism ≤ 0.1 mm/m;
Use a torque wrench to tighten the bolts diagonally and crosswise according to the standard torque (30–50 N·m);
Use metal-wound gaskets or graphite gaskets for sealing, rubber gaskets are prohibited;
Perform a leak test after installation, pressure ≥ 1.25 times the working pressure.
Clamp Type:
Clean the surface to be measured, remove oil and oxide layers, ensuring direct metal-to-metal contact;
Attach the probe to the surface, tighten the clamp bolts to ensure the probe is evenly pressed (recommended clamping force 5–10 N);
Do not use PTFE tape or adhesives, as they affect heat conduction;
Check the clamp tightness every two weeks to prevent poor contact due to thermal expansion and contraction.
Movable Threaded Type:
Clean the threaded interface, remove metal shavings and rust, ensuring smooth thread engagement;
Screw the probe to the preset depth (according to process requirements), and tighten moderately with a wrench (avoid overtightening to prevent thread stripping);
PTFE tape (1–2 turns) can be wrapped around the threads to enhance sealing, adhesives are prohibited;
Regularly check for loose threads, especially in environments with frequent starts and stops or vibrations;
When replacing the probe, only remove the probe body, retaining the threaded sleeve to reduce maintenance costs.
