Protection Tubes Explained in Detail

Protection Tubes

Thermowell, Fittings, and Terminations are all important components of a protection tube assembly. A protection tube, also called a thermowell, is a hollow sleeve that is used to protect temperature sensing elements, like thermocouples and RTDs, from the process environment. Thermowell is available in a variety of materials, like stainless steel that can withstand high temperatures and corrosive environments. Fittings are used to connect the protection tube to the process. Common fittings include weld-in fittings, threaded fittings, and sweat fittings. Terminations are used to seal the end of the protection tube and protect the sensor from the process environment. When selecting a protection tube assembly, it is important to consider the type of process environment, the temperature range, the pressure range, and the corrosion resistance required.

Features of a Protection Tube

Thermowell fittings and terminations are an essential part of any process system. They provide a means of protecting expensive instrumentation from the hostile environment of the process. A well-designed protection tube will have a number of features that make it an ideal choice for use in a process application. These features include:

  • A smooth interior surface that is free of sharp edges or burrs. This is important to prevent damage to the instrumentation that is being protected.
  • A thick wall that is resistant to corrosion and can withstand the pressures and temperatures of the process.
  • A robust connection to the process piping that will not leak or fail under pressure.
  • A flared end that allows for easy installation of the instrumentation.

Metallic/Non-Metallic Sheath or Protection 

A metal tube, mostly stainless steel, tends to have some mechanical advantages plus an increased thermal conductivity; these are usually immune to any thermal shock(s). The metal protective sheath can possibly be utilized at temperatures up to 1150 degree Celsius. Ceramic is better when more purity is needed for the sensors or products to not contaminate at high temperatures.

Ceramic Sheaths with Thermocouple Elements 

The basic use range of the ceramic sheath is at 1000 – 1800 degree Celsius. These could be in direct contact with the medium one or could also be utilized as gas-tight inner sheaths for separating the thermocouples from actual metal protective tubes. These must be installed in a hanging position above the temperature of 1200 degree Celsius for avoiding any distortion or breakage owing to bending stress. Even any hairline crack could possibly cause contamination of the thermocouples, leading to drifts or damages. Thickness of the wall of the material is also significant; where a thin-walled tube is better than a thicker wall. Cracks often occur when they are subjected to too rapid temperature alterations when quickly removed from hot furnaces.

Types of Protection Tubes

  1. Metallic 
  2. Non-Metallic 

Heatcon Sensors 

When selecting a protection tube for your application, it is important to consult with a knowledgeable supplier who can help you choose the best option for your specific needs. Contact Heatcon right away! So, if you are looking for high quality protection tubes, thermowell, fittings and terminations, look no further than our company. We offer a wide range of products that are designed to meet the highest standards of quality and safety. Our products are also available in a variety of sizes and configurations to meet your specific needs. Contact us today to learn more about our products and how we can help you protect your investment.