What is a thermowell and why is it used?

A thermowell is a protective device that houses temperature sensors (thermocouples, RTDs, temperature probes) in process piping and vessels. It isolates the sensor from the process media, allowing sensor replacement without process shutdown while protecting the sensor from pressure, velocity, and corrosive media.

What types of thermowells are available?

Four main types: (1) Threaded Thermowell - direct NPT/BSP thread installation, (2) Flanged Thermowell - for vessel/tank installation with flanged connection, (3) Welded Thermowell - direct weld to process line, (4) Drilled Thermowell - weld-in type for existing pipelines.

What is the maximum pressure and temperature rating?

Maximum pressure rating: Up to 10000 PSI depending on size and material. Temperature range: -196°C to +600°C. Actual working pressure depends on the specific thermowell dimensions and material per ASME PTC 19.3 thermowell calculations.

What materials are available for thermowells?

Stem materials: SS304, SS316, SS316L, Inconel 600, Hastelloy, Titanium. Process connection materials: SS304, SS316, SS316L. Flange materials (for flanged type): WCB, SS304, SS316. Exotic alloys available for corrosive applications.

What insertion lengths are available?

Standard insertion lengths: 50mm to 500mm. Custom lengths available on request. Lag (sheath extension): 25mm to 150mm. Stepped or tapered design available for faster thermal response.

What design standards apply to thermowells?

Design per ASME B16.34 (pressure vessel piping) and ASME PTC 19.3 (thermowell design calculations). This ensures proper wall thickness and insertion length for the application pressure, velocity, and temperature conditions.

Instrumentation

Thermowell - Protective Device for Temperature Sensors

Name: Thermowell - Protective Device for Temperature Sensors
Brand: Supreme Valves
SKU: SV-THERMOWELL-YK
Rating: 4.7 (48 reviews)

Thermowells from the Supreme Valves catalogue - protective devices for temperature sensors in process piping and vessels. Size range 1/2" to 4" (DN15 to DN100) with pressure ratings up to 10000 PSI and temperature range -196°C to +600°C. Available in threaded, flanged, and welded connections. Allows sensor replacement without process shutdown.

Quick Summary

Thermowell = Protective sheath for temperature sensors. Isolates sensor from process media (pressure, velocity, corrosion). Enables sensor replacement without process interruption. Stepped or tapered stem design for fast response. Design per ASME PTC 19.3. Used in Oil & Gas, Chemical, Petrochemical, Power, Food & Beverage, Pharmaceutical, and HVAC applications.

Thermowell - Temperature Sensor Protection Device

In Stock Up to 10000 PSI -196°C to 600°C

Key Specifications

Size: 1/2" to 4" (DN15 to DN100)

Pressure: Up to 10000 PSI

Temperature: -196°C to +600°C

Insertion: 50mm to 500mm

Connection: Threaded/Flanged/Welded

Design: ASME B16.34, PTC 19.3

Lag: 25mm to 150mm

Brand: Supreme Valves

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Product Overview

Thermowells are essential protective devices used in process industries to house temperature sensors such as thermocouples and RTDs (Resistance Temperature Detectors). They provide a pressure-tight seal between the process media and the sensor, allowing temperature measurement without exposing the sensor directly to harsh process conditions.

The Supreme Valves thermowell range offers reliable solutions for various industrial applications. These thermowells are designed per ASME PTC 19.3 standards, ensuring proper calculation of wall thickness, insertion length, and lag length to withstand process pressure and velocity forces.

Key advantages include the ability to replace temperature sensors without process shutdown, protection of sensors from corrosive or high-velocity media, and improved measurement accuracy with stepped or tapered stem designs for faster thermal response.

Types of Thermowells

Threaded Thermowell

Direct installation with NPT/BSPT thread connection. Easy removal for sensor replacement. Ideal for small to medium size pipelines. Available in 1/2" to 2" process connections.

Flanged Thermowell

For vessel and tank installation with flanged RF/RTJ connection. Provides secure mounting for larger vessels. Designed for applications requiring frequent sensor maintenance. ASME B16.34 flange ratings.

Welded Thermowell

Direct weld to process line for permanent installation. Socket weld connection for secure, leak-tight joint. Ideal for high-pressure applications where threaded connections are not suitable.

Drilled Thermowell

Weld-in type for existing pipelines. Drilled and tapped connection. Allows installation on operational lines with minimal process interruption. Suitable for retrofit applications.

Materials of Construction (MOC)

Component	Material Specification
Body & Bonnet	Ductile Iron (ASTM A536 / EN-GJS-400-15)
Stem / Spindle	SS 410 / SS 420
Seat / Trim	EPDM / NBR / Bronze

Technical Specifications

Parameter	Specification / Standard
Manufacturing / Design Standard	EN 1171 / AWWA C509 / BS 5163
Testing Standard	API 598 / EN 12266-1
Pressure Rating	PN16 / PN25