Bimetallic Thermometer Manufacturer for EPC, Power Plant & Industrial Applications

✅ Professional Bimetallic Thermometer Manufacturer in China
We are a professional manufacturer of bimetallic thermometers (bimetal thermometers) for EPC projects, power plants, petrochemical, oil & gas, metallurgy, food processing, and industrial temperature measurement applications. A bimetallic thermometer is a mechanical temperature measuring instrument that utilizes the different thermal expansion coefficients of two bonded metal strips — typically in a helical or spiral coil configuration — to convert temperature changes into mechanical rotation of a pointer on a dial. Our bimetallic thermometers feature all-stainless steel construction — including housing, stem, and wetted parts — providing excellent corrosion resistance, durability, and reliability in harsh environments. Our product portfolio includes WSS series radial-type, axial-type, adjustable-angle (universal) bimetallic thermometers, WSSX series electric contact bimetallic thermometers, and thermowell-mounted bimetallic thermometers. All products comply with GB/T 1226-2017, ASME B40.3, EN 13190, and IEC 61518 standards, available in a wide range of dial sizes, stem lengths, temperature ranges, and process connections for diverse project requirements.

📋 Product Overview & Key Features

A bimetallic thermometer operates on the principle that two metals with different coefficients of thermal expansion bend at different rates when heated. The sensing element — a helical or spiral bimetallic coil — is attached to a pointer shaft. As temperature changes, the coil winds or unwinds, rotating the pointer to indicate the temperature on a calibrated dial.[reference:0] Key features include:

📋 Technical Specification

* Custom specifications are available upon request for EPC project tenders.

📦 Available Models

🔹 WSS Series — Bimetallic Thermometer

* Standard temperature ranges: -80~40°C, -40~80°C, 0~50°C, 0~100°C, 0~150°C, 0~200°C, 0~300°C, 0~400°C, 0~500°C[reference:35]

🔹 WSSX Series — Electric Contact Bimetallic Thermometer

* Electric contact versions include built-in SPST/SPDT switches for temperature alarm and control functions[reference:39]

🔹 Thermowell Options

* Thermowells protect the thermometer stem from corrosive media and high pressure, enabling easy replacement without process shutdown[reference:42]

📊 Bimetallic Thermometer Selection Guide

❓ Frequently Asked Questions (FAQ)

Q1: What is a bimetallic thermometer?
A: A bimetallic thermometer (bimetal thermometer) is a mechanical temperature measuring instrument that uses the different thermal expansion coefficients of two bonded metals to convert temperature changes into mechanical rotation of a pointer on a dial.[reference:47] It is widely used for direct local temperature measurement in industrial processes[reference:48].

Q2: How does a bimetallic thermometer work?
A: The sensing element is a helical or spiral bimetallic coil made of two metals with different expansion rates bonded together. As temperature increases, the coil winds or unwinds, rotating the pointer shaft to indicate temperature on a calibrated dial[reference:49]. No external power is required.

Q3: What are the main types of bimetallic thermometers?
A: The main types include: Radial Type — stem perpendicular to dial (bottom connection); Axial Type — stem in line with dial (back connection); Adjustable-Angle (Universal) Type — allows 360° rotation for optimal viewing; and Electric Contact Type (WSSX) — with built-in switches for alarm and control[reference:50].

Q4: What standards do your bimetallic thermometers comply with?
A: Our bimetallic thermometers are manufactured in compliance with GB/T 1226-2017 (Chinese national standard), ASME B40.3 (American standard for bimetallic thermometers)[reference:51], EN 13190 (European standard), and IEC 61518.

Q5: What accuracy grades are available?
A: We offer three accuracy grades: 1.0% (premium grade for critical applications), 1.5% (standard grade for most industrial applications), and 2.5% (economy grade for general monitoring)[reference:52][reference:53].

Q6: What dial diameters are available?
A: Standard dial diameters include 60mm, 100mm, 150mm, and 160mm. The 100mm and 150mm sizes are the most commonly used for industrial applications[reference:54].

Q7: What temperature ranges are available?
A: Standard temperature ranges include: -80~40°C, -40~80°C, 0~50°C, 0~100°C, 0~150°C, 0~200°C, 0~300°C, 0~400°C, and 0~500°C[reference:55]. Custom ranges are available upon request.

Q8: What stem lengths (insertion lengths) are available?
A: Stem lengths range from 50mm to 2000mm[reference:56]. Standard lengths include 75mm, 100mm, 150mm, 200mm, and 300mm[reference:57]. The minimum recommended immersion depth is 2 inches (50mm) in liquids or 4 inches (100mm) in gases[reference:58].

Q9: What materials are used in bimetallic thermometers?
A: Housing: 304 or 316 stainless steel[reference:59]; Stem/Wetted parts: 304, 316, 316L stainless steel, 1Cr18Ni9Ti, or Hastelloy C-276[reference:60]; Bimetal element: Special temperature-sensitive alloy.

Q10: What process connections are available?
A: Standard connections include M20×1.5 (most common), M27×2, NPT 1/2, G1/2, and G1/4[reference:61][reference:62]. Custom threads are available upon request.

Q11: What is the response time of a bimetallic thermometer?
A: The standard response time is ≤40 seconds[reference:63]. Response time depends on the stem diameter and the thermal conductivity of the process media.

Q12: What is the difference between radial, axial, and adjustable-angle types?
A: Radial (bottom) — stem is perpendicular to the dial face, best for top-of-pipe or tank installations. Axial (back) — stem is in line with the dial, ideal for panel mounting. Adjustable-angle (universal) — features a universal joint allowing the dial to be rotated 360° for optimal viewing from any angle[reference:64].

Q13: What is a thermowell and why is it needed?
A: A thermowell is a protective tube that encloses the thermometer stem, isolating it from corrosive media, high pressure, and high-velocity flow[reference:65]. It allows thermometer replacement without process shutdown and extends instrument life[reference:66].

Q14: What is the operating pressure limit for bimetallic thermometers?
A: Without a thermowell, the maximum operating pressure at the stem is 25 bar[reference:67]. With a thermowell, pressure ratings can reach up to 40 MPa depending on the thermowell design[reference:68].

Q15: What is the ingress protection (IP) rating?
A: Standard protection is IP55 — dust-protected and protected against water jets[reference:69]. IP65 (dust-tight and jet-proof) and IP66 (dust-tight and powerful jet-proof) are available upon request[reference:70].

Q16: What is an electric contact bimetallic thermometer (WSSX series)?
A: The WSSX series features built-in electrical contacts (SPST/SPDT switches) that activate at preset temperature setpoints[reference:71]. They are used for temperature alarm and control applications, such as triggering fans, heaters, or alarms when temperature exceeds or falls below a set value[reference:72].

Q17: What are the typical applications of bimetallic thermometers?
A: Bimetallic thermometers are widely used in: Power plants — boiler and turbine temperature monitoring; Petrochemical — reactor and pipeline temperature; Oil & gas — process temperature measurement; Food processing — sanitary temperature monitoring; HVAC — air and water temperature; EPC projects — instrumentation and control systems[reference:73].

Q18: What tests are performed on bimetallic thermometers before delivery?
A: We conduct comprehensive quality tests including: (1) Accuracy test — verifying linearity and repeatability at multiple temperature points; (2) Hysteresis test — verifying minimal pointer deviation on heating/cooling cycles; (3) Response time test — verifying ≤40 seconds; (4) Mechanical endurance test — verifying durability under vibration; (5) Insulation test — for electric contact models; and (6) Pressure test — for thermowell-mounted configurations.

Q19: Do you support EPC projects with technical documentation?
A: Yes. We provide full technical support for EPC projects, including datasheets, calibration certificates, type test reports, factory acceptance tests (FAT), material traceability documentation, and custom configurations based on project instrumentation schedules and specifications. We are a trusted partner for global EPC contractors in power, petrochemical, oil & gas, and industrial sectors.

Q20: Can you provide custom bimetallic thermometer configurations?
A: Yes. We offer fully customized bimetallic thermometer solutions including custom temperature ranges, stem lengths, stem diameters, dial sizes, materials (304/316/316L/Hastelloy), process connections, mounting types, accuracy grades, electric contact options, and special markings. Our engineering team works closely with EPC contractors to develop thermometers that meet specific project technical requirements and process conditions.

📩 Contact Us for EPC Project Pricing & Technical Support

Send your project specification, temperature measurement requirements, or instrumentation schedule. Our engineering team will reply with a customized solution, BOM & datasheet within 24 hours.

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