WATROD and FIREBAR Screw Plug Immersion Heaters
Screw plug immersion heaters are ideal for direct immersion heating of liquids, including all types of oils and heat transfer solutions.
Available in a variety of sizes, Watlow screw plug immersion heaters feature both WATROD round and FIREBAR flat tubular elements.
Heating elements are hairpin bent and either welded or brazed into the screw plug-depending on element sheath and plug material compatibility.
General purpose (NEMA 1) terminal enclosures are standard; with optional moisture resistant (NEMA 4), explosion resistant (NEMA 7) and explosion/moisture resistant (NEMA 7/4) enclosures available to meet specific application needs.
Optional thermostats provide convenient process temperature regulation.

Duct Heaters
LDH SERIES and D SERIES
Constructed of sturdy 0.430 in. (11 mm) diameter WATROD heating elements mounted to a 1/4 in. (6 mm) thick steel flange, duct heaters are easily adapted to many non-pressurized air-haeating systems.
They are easily installed in applications requiring a wide range of temperature versus air flow combinations.
The modular duct heater offers increased reliability. The individual modules are removable through the housing of the assembly, which eliminates the need to pull the complete heater from the ductwork. This reduces downtime costs because the heating elements can be replaced individually. Performance improvements include quicker response time and reduced infitration from the air stream being heated into the electrical enclosure.
Watlow duct heaters offer advantages over gas or oil fired and open coil electric units with:
Installation flexibility-no flues or fuel lines
100 percent energy efficient-no energy loss up the flue
universal availability of electricity
Resistance coil in Incoloy sheath is protected from corrosive environments

Finned Heaters
375 Finned Strip Heaters
Watlow's 375 finned strip is constructed of highly-compacted MgO-based insulation, which conducts heat efficiently from the nickel chromium element wire to the sheath. Two-inch wide (51 mm) aluminized steel fins are attached in a way that maximizes surface contact so heat is transferred into the air faster. Lower sheath temperature and element life are all maximized by this finned construction.