Model HST


Thermocouple, Sulfur Processing Service

The Delta Controls Model HST Vessel Skin Thermocouple is intended to measure the skin temperature of a metal surface. The HST provides long-term accuracy and reliability in high ambient temperatures up to +1000 °F (+537 °C) for demanding applications. Available with magnetic or welded mounting options, Model HST is carefully designed to provide an accurate temperature indication of the vessel shell uninfluenced by ambient air flow nor heat sink.

Magnetic mounting allows for easy installation and as needed repositioning. A strong magnetic force binds the thermally conductive magnet face to the vessel shell. The vessel shell’s heat conducts through to the thermocouple to measure the temperature. The surrounding insulated area prevents temperature effects, such as air flow, from the surrounding ambient area.

The welded option uses a weld tab type thermowell that is welded to the vessel shell. The thermocouple is held in place with two set screws that allow the thermocouple to be easily removed without compromising the weld tab installation. The tight thermal coupling of the weld tab generally does not require any type of insulation to protect measurement accuracy.



  • Monitor metal vessel skin temperature
  • Insulated skin temperature measurement not influenced by ambient air flow
  • Maintenance free
  • Protects and extends vessel shell life while increasing operational up-time
  • Magnetic option streamlines installation
  • Robust design firmly couples to vessel shell for reliable temperature indication
  • Identify hot spots and other operational issues before the onset of corrosion


  • Thermocouple Type: K
  • Body Material: Stainless steel or carbon steel.
  • Insulation Material: Silica-alumina ceramic refractory fiber
  • Magnet Material: ALNICO 5 embedded in thermally conductive aluminum filled ceramic
  • Thermocouple Material: 0.125 in mineral insulated cable, isolated junction, 304 Stainless Steel MI
  • Conduit Outlet Box: Aluminum
  • Working Temperature: -40 °F to +1000 °F (-40 °C to +537 °C) ¹
  • Minimum Bend Radius: 0.5 in (1.27 cm)
  • Cable Length: 6 ft (1.83 m) (other lengths available)

Required Ordering Information

  • Detailed model number
  • Tag or nameplate detail (if required)
  • Documentation & testing packages (if required)

Additional Information


Thermocouple, Sulfur Processing Service

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Example Applications