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Coil heaters are your required heating elements that are formed from straight, uncoiled segments of heating cable. Forming straight cables into patterns increases the surface area and heat transfer capability, but also requires increased energy and watt density. Mostly coil heaters and cable heaters operate on AC voltages. Some include a grounding wire or provide distributed wattage arrangements to concentrate heat distribution.
There are a variety of shapes and sizes for coil heaters like straight, square, rectangular, round, coiled etc. Some devices encase the coil or cable to protect it from damage and to maximize heat transfer.
Coil heaters are made from several different types of materials and typically include insulation. Sleeve, sheath, and jacket materials include aluminum, brass, copper, iron, nickel alloy, steel, and stainless steel. Insulation materials include ceramics, mica, minerals, and fiberglass. Mica is highly resistant to acids while fiberglass is impervious to many caustics. Clamping straps provide additional protection for coils and connections.