Immersion Heaters

Screw-plug heaters thread into a standard NPT bung and are suited to smaller tanks and lower wattage requirements, offering a simple, lower-cost installation. Flanged heaters bolt onto a matching flange and support bundling multiple heating elements together for much higher total wattage, making them the standard choice for larger tanks or higher heat-up demands.

Sheath material must be chemically compatible with the specific fluid being heated, not just rated for the operating temperature — incoloy is a good general-purpose choice for water and mild chemicals, stainless steel extends compatibility to a broader range of common process fluids, and titanium is required for aggressive chemicals like chlorides, plating baths, and seawater that would corrode incoloy or stainless.

Watt density is the heater's power output divided by its sheath surface area, and it determines how concentrated the heat is at the element surface. In viscous, heat-sensitive, or fouling-prone fluids, a high watt density can scorch the fluid or cause buildup on the element even if the total wattage is otherwise correctly sized — these applications need a lower watt density, achieved with a larger or bundled element.

Wattage sizing depends on the fluid volume, its specific heat, the temperature rise needed, the desired heat-up time, and ongoing heat loss from the tank surface during steady-state operation. Undersizing extends heat-up time and may not maintain temperature under heat loss; oversizing wastes capital and can create control difficulties, so this calculation is generally worth having a supplier verify against your specific tank and process.

Yes, but oil and other viscous fluids generally require a lower watt density element than water to avoid localized overheating and fluid degradation at the element surface, along with adequate natural or forced circulation around the element to prevent stagnant hot spots. Confirm the manufacturer's watt density recommendation for the specific fluid viscosity.