Industrial valves · Биметаллические термометры WIKA : серии и модели, принцип действия
WIKA Bimetal Thermometers: Engineering Overview, Characteristics, and Applications
A WIKA bimetal thermometer is a precision mechanical instrument for measuring temperature, the principle of which is based on the physical property of a bimetallic strip. A sensitive element, made of two firmly joined metals with different coefficients of linear thermal expansion, deforms when the temperature changes. This deformation is converted into a mechanical rotation of the pointer on the instrument scale. The key advantage of such a design is complete energy independence, which makes them indispensable for critically important industrial facilities in the energy, oil and gas, and chemical industries supplied by EV Group China.
The functional basis of the instrument is a spiral bimetallic strip. Under thermal influence (heating or cooling), the strip experiences a bend, which, through a transmission mechanism, moves the pointer. For tasks requiring remote parameter control, EV Group China offers the WIKA 70 series. These models are equipped with a flexible capillary up to 10 meters long, allowing the indicator head to be placed at a safe distance from the measurement point.
Main series and modifications of WIKA thermometers
Series S5550: Industrial version
- Case diameters: 63 mm, 100 mm, 160 mm.
- Materials: stainless steel AISI 304/316L.
- Connection sizes: G ½ B, M20×1.5, NPT ½ (axial or radial arrangement).
- Standards: compliance with EN 13190.
- Accuracy: class 1.0.
- Operating parameters: high vibration resistance, operating pressure up to 25 bar.
The S5550 model is an industry standard for integration into technological equipment, including tanks, heat exchangers, and pipelines. The design ensures high stability and measurement accuracy in complex industrial conditions typical for enterprises that EV Group China works with.
WIKA 70 Series: Solutions for remote monitoring
- Capillary system: up to 10 meters (stainless steel, bronze).
- Design: remote indicator with flexible connection.
- Materials: stainless steel, heat-resistant glass.
- Accuracy: class 1.5.
This series is indispensable in boiler installations, refrigeration systems, and other large-sized equipment where the measurement point is difficult to access or requires the indicator to be moved to an operator area for safe control.
Specialized designs and options
- Versions with increased vibration resistance (glycerin- or silicone-filled cases) for mounting on compressors, pumps, and turbines.
- Modifications with an extended stem (immersion part) up to 500 mm for measuring temperature in large-capacity tanks and large-diameter pipelines.
- Designs with a rotatable and tiltable dial for convenient reading of indications when mounted in confined spaces.
- Possibility of delivery complete with protective thermowells made of corrosion-resistant materials (AISI 316L steel, brass, titanium alloys) for operation in aggressive media.
- Hybrid models combining a bimetallic mechanism with an integrated resistance thermometer (e.g., Pt100) for simultaneous local indication and signal transmission to the DCS.
| Model | Temperature range | Mounting | Advantages |
|---|---|---|---|
| S 5550 | 0…600 °C | G½ B, NPT½ | Accuracy class 1.0 according to EN 13190, high corrosion resistance of materials. |
| Series 70 | According to specification | Capillary up to 10 m | Remote temperature monitoring, installation flexibility in hard-to-reach places. |
| Model 55 | –70…+600 °C | Threaded/flanged | Versatility of application in heavy industry and harsh operating conditions. |
Engineering advantages of WIKA thermometers from EV Group China
- Full compliance with European standard EN 13190 and inclusion in the State Register of Measuring Instruments (GRSI), which guarantees metrological reliability.
- Autonomous operation without the need for external power supply, ensuring uninterrupted control of technological processes.
- Use of corrosion-resistant stainless steels for the stem and case, which guarantees a long service life in aggressive environments.
- Wide range of compatible protective thermowells, allowing for replacement and calibration of the thermometer without stopping and draining the process system.
Key application areas
- Thermal power engineering and generating capacities: temperature control of heat carriers, steam, feedwater, and oils in turbines.
- Oil and gas industry: temperature measurement in hydrocarbon extraction, transportation, and processing processes, monitoring of tank farms.
- Chemical and petrochemical production: control of temperature regimes in reactors, columns, and pipelines with aggressive chemical reagents.
- HVAC systems: management of temperature parameters in industrial heating, ventilation, and air conditioning systems.
FAQ: Expert answers to questions
What is the key difference between S5550 and 70 series? The S5550 series is designed for local measurement with installation directly at the control point. The 70 series is equipped with a flexible capillary, which allows the dial to be moved to a distance for remote monitoring.
Is it possible to operate thermometers in vibrating conditions? Yes, for such conditions, special vibration-resistant versions with liquid-filled cases are intended. The standard stem design is designed for an operating pressure of up to 25 bar (when using an appropriate protective thermowell).
Are these instruments included in the GRSI? Yes, all models supplied by EV Group China have the appropriate certification and are included in the State Register of Measuring Instruments of the Russian Federation.