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Helical Thermowells

Helical thermowells isolate and protect a temperature sensor’s sensing element from pressurized, high-velocity, and corrosive materials.

A thermowell is most often used to measure temperature in a setting where the insert reaches into the liquid or gas flowing through the process. When a thermowell is installed into a flowing liquid or gas, the inserted stem will cause a vortex to form. Because the vortices cause the thermowell to resonate, this may harm the stability and integrity of the instrument or the installation. So how can you make sure that these vortices are less of an issue?

There are ongoing issues with standard thermowells—namely, the considerable and measurable temperature management problems involving high-velocity processes. While quick fixes such as changing the root and tip diameters have been implemented, they still result in sizable and inaccurate results. Traditional methods for reducing thermowell vortex-induced vibrations include:

  • Shortening the insertion length
  • Increasing the root diameter
  • Increasing the tip diameter
  • Adding support collars

Helical thermowell with transmitterA helical thermowell has the same shape, dimension, material, and mounting connections as a standard thermowell, but also a helical strake at the tip that reduces vibrations. Helical thermowells isolate and protect a temperature sensor’s sensing element from pressurized, high-velocity, and corrosive materials. It also provides temperature measurement to ensure the temperature is within the required range.

It is an easy-to-install thermowell that reduces the amplitude of vibrations by more than 90 percent. There’s no need to change the dimensions of the thermowell or perform expensive and time-consuming retrofitting to pass wake frequency calculations. They ensure longer life and accurate measurements while allowing the sensing instrument to be removed without shutting down the process.

Vortex-induced vibrations (VIV) are not an issue for helical thermowells. The strakes reduce the amplitude of oscillation compared to plain cylindrically shaped thermowells. Various laboratory tests have proven beyond doubt that helical strakes lower VIV by more than 90 percent compared to a standard thermowell. The sharp edges of the three helical strakes separate the flow, and the helical shape redistributes the vortices. As a result, the lift and drag forces are greatly minimized.

Industries that use helical thermowells

Helical thermowells are used in several industries, including petrochemicals and oil and gas. These devices play a crucial role in the safe and efficient operation of industries by protecting temperature sensors against damage from immense pressure, material velocity, and corrosion.

Helical thermowells are used in the following industries:

  • Petrochemical and chemical plants
  • Water and wastewater pressure control
  • Oil and gas
  • Power generation

Helical ThermowellTypes and uses of helical thermowells

The Temp-Pro helical thermowell design eliminates wake frequency calculations. Instead, steady-state stress and pressure calculations can be used. The small tip diameters and roots make for a fast response to temperature variations. Additionally, the accuracy of temperature measurements and response time are significantly improved compared to the typical thermowell.

Some common helical thermowells are made from 304 stainless Steel, 316 stainless Steel, and Monel, but there are many materials to choose from according to your process needs.

With helical thermowell technology, companies can ensure more accurate gauges and eliminate concerns about failure during the manufacturing process in high-velocity environments. Helical thermowells not only meet ASME PTC 19.3 TW-2016 requirements but also reduce the amplitude of oscillation by more than 90 percent compared to other standard round bar designs.

The type of thermowell used is essential to ensuring the device effectively detects increased temperature through temperature sensors in various industries. This can also help prevent overheating, which could result in breakdowns in industrial processes.

Thermowell helical styles include:

  • Helical – Threaded
  • Helical –- Socket-Weld
  • Helical – Flange
  • Helical – Vanstone

Client examples

  • John Cockerill Energy: A player in the energy transition, John Cockerill Energy specializes in steam production. They provide Heat Recovery Steam Generators, Once Through Boilers and Integrated Renewable Solutions.
  • Mitsubishi Power Americas: This company leads the industry in power generation and energy storage solutions. Power generation solutions include natural gas, steam and aero-derivative turbines; power trains and power islands; and geothermal systems.
  • Suncor Energy Company: Serves as a unique and sustainable globally competitive integrated energy company. Produces and provides energy from a mix of sources, ranging from oil sands to renewable fuels.

Helical Thermowell with terminal headKey Takeaways

  • Helical thermowells are devices that protect temperature sensors from harsh conditions by providing extra strength and stiffness through helical strakes on the stem.
  • Vortex-induced vibrations (VIV) can be a problem for standard thermowells, but helical thermowells have been shown to reduce the amplitude of oscillations at high velocity by more than 90 percent.
  • Helical thermowells are commonly used in the petrochemical, oil and gas, water and wastewater pressure control, and power generation industries.
  • Helical thermowells are available in different materials, including 304 stainless steel, 316 stainless steel, and Monel, and various styles, including threaded, socket-weld, flange, and vanstone.
  • Helical thermowells eliminate the need for wake frequency calculations and improve the accuracy of temperature measurements and response time.
  • Helical thermowells have been used by companies such as John Cockerill Industry and have been proven to meet ASME PTC 19.3 TW-2016 requirements.

Don’t let temperature control issues negatively affect your business operations. Trust Temp-Pro as your reliable, efficient, cost-effective solutions provider for all your industrial needs. 

Temp-Pro offers a wide range of temperature control equipment and services, including industrial temperature sensors, helical thermowells, and industrial electrical enclosures. Our team of experts is dedicated to meeting your unique needs and exceeding your expectations. 

Contact us today to schedule a consultation and see how Temp-Pro can help your business thrive.


Marketing And Sales Specialist at Temp-Pro | Website | + posts

Nicole Chotain is a passionate marketing and sales specialist in the temperature sensor industry who finds it incredibly fulfilling to be involved in marketing and selling crucial components used in power generation and renewable energy. She takes great joy in creating remarkable campaigns, forging meaningful connections between Temp-Pro and its customers, and driving the growth of the brand.

Sales Engineer And Commercial Sales Manager at Temp-Pro | + posts

Neal Messier is a dedicated sales manager at Temp-Pro. With 17+ years of experience working with instrumentation in diverse industrial and process industries particularly power generation, he is passionate about the temperature sensor industry and uses his strong technical background and comprehensive industry knowledge to fulfill client’s temperature sensor needs.

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