Open coil heating elements

Types of open coil heating elements

Open coil heating elements are resistance wires usually made of nickel-chromium or iron, wound into coils, and mounted on insulators (ceramics). They can come in various shapes. Heat transfers to the surrounding air when they are energized. Open coil heating elements come in two types: vertical and horizontal.

• Horizonal open coil heating elements: A horizontal open coil heating element usually has a horizontal coil. It is often mounted on a flat insulator or brackets. A horizontal configuration tends to have an even heat distribution. It's typically used where equipment height is limited. It's also commonly used in the aviation industry and automotive sector. Horizontal coils can be found in air ducts, ovens, kilns, and other areas where limited spacing exists.
• Vertical open coil heating elements: A vertical open coil heating element usually has a vertical coil. It has a relatively small footprint. Vertical coils can be used to heat gases or fluids moving through pipes or vessels. It's often used in applications like fluid heating in chemical processing or agricultural greenhouses. Vertical elements are also common in conjunction with fans to produce air heating appliances.

Specifications & Maintenance

• Sizes and Shapes:

  The sizes and shapes of open coil heating elements will vary based on where they are used. Generally, they come in long strands or coils. The strand length usually measures from several centimeters to over one meter. The thickness of the strands can vary, but it's usually thin enough to allow for flexible placement. Common shapes include spirals or zigzags, which allow them to cover more surface areas.

• Materials:

  Open coil heating elements are often made of metal alloys such as nickel-chromium or iron-chromium-aluminum. The alloys contain various percentages of each element, which affects features like corrosion resistance and lifespan. Some alloys may be better for over 1,500°F high-temperature applications or more humid environments.

• Power Ratings:

  Power ratings for open coil heating elements are measured in watts or kilowatts. Generally speaking, household heating elements are around 1-3 kilowatts. Higher power ratings are more common in industrial settings. A higher power rating means the element produces more heat but also consumes more electricity.

• Mounting Options:

  Open coil heating elements can be fixed with different methods according to the application needs. The most common installment method is the threading technique, where threads are incorporated into the design of the coils, and the coil is threaded onto fixtures or other supports that have matched threads. Another way is the clamps method, where clamps or clips are used to securely fasten the heating coil to a mounting plate or chassis. Adhesive or cement mounting refers to an installment method in which a specific adhesive that can withstand heat and a cement-based support medium is used. This provides a smooth heat distribution but may require more maintenance over time. Some heating coils come with brackets or flanges that already have pre-drilled mounting holes. This makes the installation easier and more effective.

• Voltage:

  The voltages required for open coil heating elements can vary based on applications. Standard household voltages are usually 120 volts. However, more industrial and commercial uses tend to have higher voltages between 240-600 volts.

Proper maintenance can ensure a longer service life of the open coil heating element. Users should periodically inspect the heating source for signs of damage like cracks or breaks and replace them promptly. Also, make sure to check if the coil is crowded or coated with other substances, as this may block heat distribution. If there are any residues, users should have them cleaned immediately. Besides, open coils should be kept dry and away from moist environments, as excessive dampness can make them corrode more quickly. Last but not least, users should pay attention to the power supplied to the open coil heaters to avoid overheating caused by excessively high voltage.

Usage scenarios of open coil heating elements

Open coil heating elements are versatile tools used in different industries and applications.

• Industrial manufacturing

  Open coil heating elements are widely used in industrial manufacturing as part of the production line. They can provide a constant heat supply, maintaining the temperature during the manufacturing processes. For example, open coil heating elements are used in the glass-making industry for melting and shaping glass. They can heat the materials to a high enough temperature and ensure that the glass products come out with excellent quality.

• Food industry

  In the food industry, open coil heating elements can be used for cooking equipment, such as fryers, grills, and toasters. They provide the necessary heat to fry food evenly and create a crispy texture. Also, heating elements are used for food processing equipment. They can offer the required heat treatment, such as sterilization and pasteurization, to ensure the safety and wholesomeness of food.

• Scientific research

  Open coil heating elements can also be used for scientific research. In the laboratories, they can be used to heat beakers, flasks, and other experimental devices. They allow precise control of temperature, which creates a favorable research environment for chemical reactions and biological experiments.

• Medical application

  Open coil heating elements can be used in the medical field to sterilize medical devices or heat and maintain the temperature of drugs and intravenous fluids.

• Agriculture and horticulture

  In agriculture and horticulture, open coil heating elements are used in greenhouses. They can help heat and maintain the temperature of the greenhouse, which promotes plant growth and flowering, especially in cold weather.

• Automotive industry

  In the automotive industry, open coil heating elements are widely used in the manufacturing and maintenance of automobiles. For example, they can be used in automotive repair shops for bake drying and curing processes. Open coil heating elements can also be used in the interior of automobiles, such as heating seats and heating coils in steering wheels.

• Plastic and rubber industry

  Open coil heating elements are used in plastic and rubber manufacturing equipment. They provide the necessary heat for the extrusion, injection molding, and vacuum forming of plastic. The precise control of temperature helps to improve the fluidity of materials and molding quality.

How to choose open coil heating elements

Below are the tips to keep in mind when selecting open coil heating elements.

• Functionality

  Consider the functionality of the heating element. Does the user require a fast heating element, or is the gradual heating preferable? Fast heating elements are generally fine, coiled heating elements, while those providing even heating have a greater surface area.

• Temperature range

  Open coil elements come in various types based on the temperature they can reach. While nichrome wire can reach higher temperatures, other alloys like kanthal are better for high temperatures.

• Availability

  Opt for open coil heating elements that are easy to find in the local market, or look for reliable suppliers when searching online. Whichever type one chooses, it should always be readily available for replacement.

• Compatibility

  Check the compatibility of the element with the existing equipment. Consider the size, voltage, and wattage to ensure a proper fit and functionality.

• Cost

  Since it comes in different types and sizes, the price will differ as well. Generally, bigger coils tend to cost more. Open coil heating elements that provide even heating are more expensive than those that heat quickly. Check the costs but choose wisely so performance is not compromised.

Open coil heating elements Q&A

Q1: How efficient are open coil heating elements?

A1: Open coil heating elements are quite efficient. They convert approximately 90% of the consumed electricity into heat. However, heat losses to the surrounding environment can decrease their overall efficiency.

Q2: What wattage is suitable for an open coil heating element?

A2: The required wattage for an open coil heating element depends on the intended application. Typically, wattages range from 500 to 5000 watts. For heating small spaces or cookware, a wattage below 1500 is sufficient. Higher wattages are necessary for industrial heating purposes.

Q3: Can open coil heating elements be dimmed or regulated?

A3: Yes, open coil heating elements can be dimmed or regulated using rheostats, dimmers, or solid-state relays. This allows control over the temperature, heat output, and energy consumption of the heating element.

Q4: Can open coil heating elements be repaired if they break?

A4: If open coil heating elements break, they cannot be repaired. Because they are coiled wires, the unexpected break cannot connect the wire again internally and externally. Even if it can be linked, the heating element will be uneven heat distribution. Therefore, it is better to replace it.