THERMOWELLS - Protection for temperature sensors

Thermowells are used to guard the temperature sensors that are installed in industrial processes. It is made up of a tube that is drilled and machined from a solid bar stock that is closed at one end and mounted in the process stream. Sensors such as thermocouples and RTDs are inserted through the open end of the thermowell and placed at the tip of the closed end.

Types of Thermowell:

Threaded Thermowell:
Flanged Thermowell
Socket Weld Thermowell
Welded Thermowell
Lap Joint (Van Stone) Thermowell
Straight-shank Thermowell
Tapered Thermowell
Step Shank Thermowell
Fabricated Thermowell
Bar stock Thermowell
Van-Stone Thermowell
Helical Strake Thermowell
Sanitary Type: Thermowell

Are thermowell necessary?

Thermowells provide protection for temperature probes against unfavourable operating conditions such as corrosive media, physical impact (e.g., clinker in furnaces), and high-pressure gases or liquids. Their use also permits quick and easy probe exchange without the need to "open up" the process. It is a closed-end reentrant tube designed for the insertion of a temperature-sensing element and provided with means for a pressure-tight attachment to a vessel.

Here's why Tempsens should be your choice to buy thermowell:

Tempsens Thermowell is a tube-like structure, closed at one end, which protects the probe and allows its removal without breaking the liquid seal. We provide thermowell drilled from solid bar stock with the highest pressure ratings, and welded models are also available. We also manufacture special types of Thermowell on customer demand and as per application requirements.

Metal Thermowells with Tungsten Carbide, Cerami, PTF, PVDF or PFA Coatings
Solid sintered tungsten carbide
Silicon Carbide
Platinum Thimble
Tantalum Thimble
Tantalum, Titanium, and Nickel Cladding Graphite Thermowells
IBR Stamped Thermowells

Tempsens offers a full range of welding capabilities.

Welding is the process of joining two metals by heating them to a suitable temperature. It may be done with or without the application of pressure, and with or without a filler. Capable of Argon welding and metal arc welding for strong joints and a clean & homogeneous surface.

Types

Full Penetration Welding: This type of welding ensures a fully welded interface between the two parts and is generally the strongest joint.
Partial Penetration Welding: This type consists of a partially welded interface with filler metal being laid on the surface of the two metals.

We are experienced in welding stainless steel, nickel-based alloys, and other exotic metals. Our welders are certified and they use the most sophisticated equipment including MIG, TIG, microplasma and a laser welding machine with a rotor and other facilities.

How to select a THERMOWELL?

It depends on the following factors:

The longevity factor

The selection of thermowell material is governed according by the corrosion the well faces. The high polish given to all stainless wells come up with maximum corrosion resistance.

The Interchangeability factor

The selection of a standard bore diameter can produce extreme flexibility. The same well can accommodate a thermocouple, a resistance thermometer, and a bimetal thermometer

Connection: The Installation factor

All threaded wells are made of easily welded or brazed materials. Welding and brazing are important for installations requiring seals. The pipe thread provides mechanical strength, and the weld provides the seal.

Insertion length: The velocity factor

The distance from the tip of the well to the underside of the thread or other connection is defined as the insertion length.

The velocity rating factor

A tapered shank provides greater rigidity with same sensitiveness The higher strength to weight ratio gives these wells a higher natural frequency than the equivalent-length straight-shank well, thus permitting operation at a high fluid velocity.

Velocity rating of well

Fluid flowing by the wells forms turbulent wake, which has definite frequency based on the diameter of the fluid. The well must have sufficient capacity so that the wake frequency will never equal the natural frequency of the well itself. The natural frequency of the well correspond with the wake frequency, the well would vibrate to destruction and break off in the piping.

How deep should a thermowell be?

The depth of the thermowell measures from the tip of the well to the underside of the thread or other connection, which is defined as the insertion length. For best accuracy, this length should be sufficient to permit the entire temperature-sensitive part of the element to project into the medium being measured. A properly installed element should be immersed in liquid up to its sensitive length plus one inch, and in air or gas, it should be immersed up to its sensitive length plus three inches.

Further Reading

THERMOWELLS - Protection for temperature sensors

Categories