Immersion Heater Elements
Since immersion heating elements are used to heat many corrosive substances, they are often covered with a protective outer sheath. A wide range of sheath materials used includes titanium, stainless steel, Incoloy, copper, brass and cast iron. However, different sheath materials work best for different substances. For example, stainless steel is best for mild acids, while Incoloy is best for high temperature air and gases as well as alkaline solutions. Common industries that utilize immersion heater elements include automotive, manufacturing, wastewater, commercial, electronics and aerospace for applications such as heat transfer systems, storage tanks, oil and water heaters, railroad tank cars, process systems and boilers.
A typical construction of an immersion heater includes a
tubular heating element and an electrical terminal that remains outside of the substance. Generally, immersion heating elements come in three main style types: over-the-side, flanged (through-the-side) and threaded (screw-plug). The over-the-side style of immersion heating elements is designed for containers in which through-the-side immersion heating elements cannot be easily installed. Thus, the immersion heater is installed through the top of the container, allowing the heating element to lie along the side or at the bottom of the container. Flanged immersion heaters are a through-the-side style. They are usually round or square-shaped and are welded or brazed onto pipe flanges. They are then bolted to a matching flange that has been welded to a container wall. This style of immersion heater is the most common method used for heating liquids. Threaded, or screw-plug, immersion heaters are very similar in style to flanged immersion heaters. Instead of a flange, the hairpin bent tubular heating element is welded to a plug that is screwed into the container through a threaded hole in the container wall. Screw plug immersion heaters work best in process water heating and freeze protection applications.
