Among the many measurement solutions that Thermo-Kinetics Measurement & Control Ltd. offers under its own brand name is a series of protection tubes. These devices are used to protect thermocouples and other sensors against mechanical damage and contaminating atmospheres. Each of these units is closed at one end and typically incorporates some way for the tube, sensor, and connection head to be assembled and mounted into the process.
Available in various materials
These products are available in various kinds of materials, which are chosen based on the environment to which the user will be subjecting the sensor assembly. The materials that go into these protection tubes include ceramic, stainless steel, inconel, hexoloy, silicon carbide, LT-1 metal ceramic, lava coating, sialon, cast iron, and other alloys.
Ceramic protection tubes are dense, fine-grained, nonporous compositions that stay gas-tight even when temperatures approach their melting points. Customers typically use them at high temperatures with platinum-type thermocouples, but using them with base-metal thermocouples is prevalent in atmospheres harmful to metal tubes and not subjected to mechanical abuse. Meanwhile, hexoloy protection tubes are impermeable to gases at pressures of up to 4,500 psig, and their fine-grain structure offers high strength and resistance to abrasion and corrosion.
Thermo-Kinetics also supplies silicon carbide tubes, which are resistant to gases and flames. They are usable at temperatures as high as 1,650 degrees Celsius and are distinguished by high thermal conductivity, excellent thermal shock properties, and strong resistance to mose corrosive fluids. Since these tubes are porous, businesses can use them for secondary protection from extreme temperatures, abrasive atmospheres, and direct flame impingement. Sialon protection tubes, made from a high-strength ceramic, have high heat- and abrasion-resistance characteristics, as well as high thermal shock resistance and tolerance of heat up to 1,250 degrees Celsius.
Metal protection tubes provide good mechanical protection for base-metal thermocouples up to 1,150 degrees Celsius in oxidizing atmospheres. All metals are porous above 870 degrees Celsius, so a ceramic primary tube may be required for protection from detrimental vapours. Other options available include cast iron and lava-coated tubes.
To learn more, contact Thermo-Kinetics or call 1-800-268-0967.