Thermowells

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We are well known manufacture of Thermowells in the market. Thermowells  are basically cylindrical fittings used to protect temperature sensors installed in the industrial process. A thermowell consists of a tube closed off on one end and threaded at the other end. It is an enclosure used to protect a Thermometer, RTD Sensors or thermocouple from exposure to hazardous materials or extreme environments.

According to the American Society for Testing and Materials (ASTM) has defined the term thermowell as  a closed end re-entrant tube designed for the insertion of temperature sensing element, and provided with means for a pressure tight attachment to a vessel.

Thermowell Material: Thermowells are Manufactured from forged bar stocks or Pipes. Thermowells are available in Carbon Steel, Stainless Steel, Monel, Hastelloy, Titanium, Copper, Molybdenum and Chromium steel, Nickel etc. depends on the requirements of the conditions.

Category:

THERMOWELL TERMINOLOGY:

THERMOWELL TERMINOLOGY

  • Bore Diameter (B): This is the inside diameter of the Thermowell.
  • Tip Thickness (E): Thickness of the bottom portion of Thermowell.
  • Base Diameter (Q): This is the outside diameter of the Thermowell shank and is a densest part because the outside surface area is exposed to the hazardous materials of the process.
  • Bore Depth (S): Total length of the bore.
  • Lagging Extension Length (T): The lagging extension commonly referred to as the “T” length is located on the cold side of the process connection and is usually an extension of the hex length
  • Tip Diameter (V):Thermowell bottom end Diameter.
  • Insertion length (U): Thermowell Insertion lengths are often called the “U” length which is the measurement of the Thermowell shank length from the bottom of the process connection to the tip of the Thermowell.

 

Instrument connection: Instrument connection is basically a temperature element connection inside the thermowell on the top side. It should be ½” NPT (F) or depend on the element connection size.

 

Process Connections: Thermowells are distinguished according to their connection. Following are some popular types used in industries.

FIG. : THERMOWELL PROCESS CONNECTION

TYPES OF THERMOWELL AND THERMOWELL SHANK:

THERMOWELL TYPES

  • Flanged Thermowell :Flanged thermowell features a thermowell collar, which is located on the mating flange. This type of thermowell is used when frequent replacement or removal is required. Flanged thermowell is used in high temperature applications.
  • Threaded Thermowell :As the name implies, these thermowells are  screwed directly into the process piping or a vessel, which allows for easy installation and removal when necessary. While this is the most common method of mounting, it has the lowest pressure rating, and threaded connections are prone to leakage. Threaded Connection may be BSP or NPT depend on the relative Component thread.
  • Socket weld Thermowell: These thermowells may be directly welded into the socket of weldolet.
  • Weld in thermowell: These thermowells are directly welded into the piping or process vessel. As the thermowell is welded into the pipeline, it only used for permanent connections. Used in application with the high-velocity flow, high temperature and/or high pressure.

THERMOWELL SHANK TYPES

The most widely available thermowell shank designs include:

  • Straight shank Thermowell: It maintains the same size throughout the entire thermowell immersion length.
  • Tapered Thermowell: Its external diameter drops off steadily all over the thermowell immersion length. In general, a heavy duty tapered shank thermowell finds its use in applications involving high velocity.
  • Step shank Thermowell: Its external diameter happens to be ½” near the end of the thermowell immersion length which results in fast time of response.