Bimetallic thermometers are widely used in various industries for temperature measurement due to their durability, simplicity, and cost-effectiveness. A critical aspect of their installation is the connection method, which ensures secure attachment to the process while maintaining accurate temperature readings. Common connection types include threaded, flanged, and socket weld fittings, each suited for different applications.
1. Threaded Connections
Threaded connections are the most common type, featuring male (external) or female (internal) threads that screw directly into a corresponding process connection. Common thread standards include:
- NPT (National Pipe Thread): A tapered thread widely used in North America, providing a tight seal.
- BSP (British Standard Pipe): Popular in Europe and Asia, available in parallel (BSPP) or tapered (BSPT) versions.
Threaded connections are easy to install and suitable for low-to-medium pressure applications.
2. Flanged Connections
For high-pressure or large-diameter pipelines, flanged connections are preferred. A flange is bolted to a matching process flange, ensuring a robust and leak-proof seal. Flanges comply with standards like ANSI, DIN, or JIS and are ideal for harsh industrial environments.
3. Socket Weld Connections
In compact or high-vibration systems, socket weld fittings provide a strong, permanent connection. The thermometer’s stem is inserted into a socket and welded in place, ensuring excellent mechanical strength. This method is common in petrochemical and power plants.
Selection Considerations
When choosing a connection type, factors like pressure, temperature, vibration, and corrosion resistance must be considered. Proper installation ensures long-term reliability and measurement accuracy.
In summary, bimetallic thermometer connections play a vital role in their performance. Selecting the right type based on application requirements enhances durability and measurement precision.
