Precision Flanges for Temperature Sensor Installations
Thermometrics supplies flanges and process fittings specifically selected and machined for temperature sensor and thermowell installations. Our flanges are manufactured to ASME B16.5 standards and available in pressure classes from ANSI Class 150 through Class 2500, covering the full range of industrial process pressures.
Each flange is supplied with the correct bore size for your thermowell or sensor assembly, ensuring a proper fit and reliable seal. Custom bore sizing, face finishes, and material specifications are available to meet your exact process requirements.
- Weld neck, slip-on, socket weld, threaded, blind
- ANSI Class 150, 300, 600, 900, 1500, 2500
- ASME B16.5 compliant
- Custom bore sizing for any thermowell
- Raised face (RF) and ring-type joint (RTJ) available
- Multiple materials: carbon steel, 316 SS, alloy steel
Matched to Your Thermowell
When ordering flanges with a thermowell, we precision-bore the flange to match the thermowell shank diameter, ensuring proper fit and alignment. This eliminates the common field problem of mismatched bore sizes between separately purchased flanges and thermowells.
Material Test Reports
All flanges are supplied with material certifications per ASTM standards. Full material test reports (MTRs) with chemical analysis and mechanical properties are available upon request, as required for ASME B31 piping code compliance.
Available Flange Configurations
Weld Neck Flanges
Features a long tapered hub that is butt-welded to the pipe, providing the strongest and most fatigue-resistant connection. The gradual transition from flange to pipe reduces stress concentration at the weld joint. The preferred choice for high-pressure, high-temperature, and critical-service applications.
Standards: ASME B16.5, ASTM A182 (stainless), ASTM A105 (carbon steel)
Slip-On Flanges
Slides over the pipe or thermowell and is fillet-welded on both the inside and outside. Easier to align than weld neck flanges and less expensive. Suitable for moderate-pressure applications (typically up to ANSI Class 300) where maximum joint strength is not required.
Note: Strength is approximately 2/3 of a weld neck flange due to the fillet weld geometry.
Socket Weld Flanges
Features a counter-bore that accepts the pipe or thermowell, which is then fillet-welded from the outside only. Provides good alignment and a smooth bore transition. Commonly used for small-diameter (NPS 2 and below), high-pressure piping systems.
Best for: Small-bore piping, instrument connections, Class 300-1500.
Threaded Flanges
Internal NPT or BSP threads allow connection without welding. Useful in low-pressure, non-critical applications or where welding is impractical (e.g., fire hazard areas). No weld means easy assembly and disassembly. Not recommended for elevated temperature service where thread creep may occur.
Best for: Low-pressure utility services, where hot work permits are restricted.
Blind Flanges
Solid flanges used to seal the end of a piping system, vessel, or pressure vessel opening. In temperature sensing applications, blind flanges are sometimes used as mounting plates for thermowell penetrations, particularly in vessels where the thermowell must be installed through the vessel wall.
Note: Available with custom bore and pilot for thermowell pass-through applications.
ANSI Pressure Class Ratings
Maximum allowable working pressures per ASME B16.5 at the specified temperature for carbon steel (ASTM A105) flanges. Stainless steel and alloy flanges have different pressure-temperature ratings — consult our engineers for specific alloy data.
| ANSI Class | Max Pressure at -29°C to 38°C | Max Pressure at 260°C | Max Pressure at 427°C |
|---|---|---|---|
| Class 150 | 285 psi (19.6 bar) | 260 psi (17.9 bar) | 170 psi (11.7 bar) |
| Class 300 | 740 psi (51.0 bar) | 675 psi (46.5 bar) | 450 psi (31.0 bar) |
| Class 600 | 1,480 psi (102 bar) | 1,350 psi (93.1 bar) | 900 psi (62.1 bar) |
| Class 900 | 2,220 psi (153 bar) | 2,025 psi (140 bar) | 1,350 psi (93.1 bar) |
| Class 1500 | 3,705 psi (255 bar) | 3,375 psi (233 bar) | 2,250 psi (155 bar) |
| Class 2500 | 6,170 psi (425 bar) | 5,625 psi (388 bar) | 3,750 psi (259 bar) |
Material Specifications
| Material | ASTM Specification | Typical Applications |
|---|---|---|
| Carbon Steel | ASTM A105 | General purpose, steam, water, oil, gas |
| 304 Stainless Steel | ASTM A182 F304 | Moderate corrosion, food, water |
| 316 Stainless Steel | ASTM A182 F316 | Chemical, pharmaceutical, marine |
| 316L Stainless Steel | ASTM A182 F316L | Sanitary, welded applications |
| Alloy Steel (CrMo) | ASTM A182 F11, F22 | High-temperature steam, power plants |
| Inconel 600 | ASTM B564 N06600 | High-temp corrosive environments |
| Monel 400 | ASTM B564 N04400 | Seawater, HF acid service |
Face Finishes & Gasket Considerations
The flange face finish directly affects gasket sealing performance. Thermometrics supplies flanges with the appropriate face finish for your gasket type and service conditions.
- Raised Face (RF): Standard 125–250 µin Ra finish for spiral-wound and sheet gaskets. The most common configuration for general industrial service.
- Ring-Type Joint (RTJ): Machined groove for metal ring gaskets. Required for high-pressure (Class 900+) and high-temperature applications.
- Flat Face (FF): Full-face contact surface for use with full-face gaskets. Required when mating with cast iron or ductile iron flanges.
- Smooth Finish (63 µin Ra): For use with PTFE and other soft gasket materials in chemical service.
Custom Bore Sizing
We machine the flange bore to match your specific thermowell OD. Standard bore sizes: 0.760", 1.000", 1.250". Custom bores machined to your drawing. This eliminates field-fitting issues and ensures concentricity between the thermowell and flange.
Complete Assemblies
Order your flange pre-assembled with a Thermometrics thermowell for a complete, ready-to-install unit. We handle the bore matching, welding (if applicable), and pressure testing so you receive a single part number for procurement simplicity.
Ready to Spec
Your Sensor?
Whether you need a standard catalog configuration or a fully custom engineered assembly, our technical team responds to all quote requests within one business day.