Flanged industrial immersion heaters are amongst the most popular heaters owing to wide customization, easier installation and operations in stringent environment. Made by brazing or welding flange with several hairpin elements or bulge tubular elements, these are designed for heating chemical, petroleum and water based applications specially heat transfer fluids, medium and lightweight oils and water in tanks and pressure vessels. A thermocouple or RTD is often used within the bundle of elements to maintain the desired target temperature. Extra wiring boxes to make electrical connections are provided with it. Tubing known as a thermowell is used to protect thermocouples and heating elements. Temperature readings are then transmitted to a control unit that regulates power. Although, they occupy a small space, but have a large heating element which is perfect for applications which require high wattage heating. This is one of the most efficient forms of process heating with nearly 100 percent efficiency. Different alloys and materials can be used to suit specific applications.

For instance, steel flanges are used for deionized water, lubricant oils, heavy and light oils, waxes as well as mildly corrosive liquids and low flow gas and water tank heating. Stainless steel flanged heating elements are used with mild and severe corrosive solutions and military applications. The sheath materials used can be steel, stainless steel, copper as well as exotic alloys such as incoloy.