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Housings and sheaths for temperature sensors
Our temperature sensors are specifically designed for many different types of harsh and reducing atmospheres and therefore we supply protection sheaths suitable for each application.
Consideration needs to be given to:
The maximum and normal running temperature of a process
Any chemical attack present
Physical knocks or vibration in use (including carriage and plant handling)
Protect the sensor from contamination
Maximum design pressure
The connection of the sensor to the plant or equipment
If the sensor is to be replaceable within the protection sheath
Sheaths suitable to the application
At low temperatures PVC, Silicon rubber, FEP, PFA or PTFE (polytetrafluroethane / teflon) sheaths are common to 260°C. Above this stainless steel and other metal alloys are used. For high temperatures ceramic is used. Common ceramics include: Pythagoras, Alsint / Recrystalised Alumina (RA), Aluminous and Impervious Aluminous Porcelain (IAP). Platinum Rhodium alloy sheaths are used for immersion into glass.
Molten aluminium temperature sensors can utilise cast iron due to its cheapness and adequate chemical resistance. Chemical plants can demand Inconel ( and other Nickel alloys), Monel Hastelloy or a range of fabricated coatings such as tantalum. Mineral insulated designs incorporate the conductor within a metal protection sheath (Usually Stainless Steel or Inconel Alloy 600) held apart with a compacted ceramic powder. This forms the most robust and tough sensors available. Overall sizes down to 0.25mm diameter is possible. The sensor is virtually indestructible except through over temperature exposure. The unit can be formed to almost any shape to suit an application including tip diameter reduction to decrease response time. Compression glands can easily be used with mineral insulated thermocouple and resistance thermometer (RTD) sensors to provide sealing. Process fittings can include fixed or moving threads and flanges.
Protection Sheath Designs
The length, design, diameter, bore and materials of the protection sheaths can vary according to your personal requirements.