A cartridge heater is a heavy-duty, tube-shaped industrial heating element. They are commonly used in the process heating industry and are custom-manufactured to a specified watt density. A few features to look for in a cartridge heater include: Common metals used for the heating element, PTC heating elements, Split sheath cartridges, and Thyristor power controls.
Common metals used for cartridge heaters
Cartridge heaters are insulated devices that transmit heat to the material they’re designed to heat. They typically use Nichrome wire, which is a nickel-chromium alloy, as the heating coil. Nichrome wire has a high resistance to electrical current and varies in density based on the number of turns per inch around the core. The coiled wire is wrapped around the sheath of the cartridge heater and is filled with insulating materials, such as magnesium oxide. The coiled wire is protected by a sheath made of one of several common metals.
The main feature of cartridge heaters is that they are ideal for a wide range of temperature applications. They can withstand temperatures as high as 1400 deg F and transfer energy efficiently. In addition, the metallic sheet surrounding the heating element prevents oxidation. Lastly, they ensure full heat transfer and minimize heat loss, resulting in low electricity bills.
PTC heating elements
PTC heating elements are a key component in cartridge heaters. Made from a combination of two semiconductor materials, Titanium and Barium, PTC heaters produce high heat by heating the surface of the material. However, because of the resistance in the crystal structure of the materials, the material produces minimal heat when no electrical current is passed through it. This cartridge heater property makes the PTC heater self-regulating.
A PTC heating element is also called a self-regulating cartridge heater. The heating element is temperature and current self-regulating, ensuring constant performance and maximum energy efficiency. Because of its temperature-regulating properties, the PTC heating element has a negative resistance. As a result, the heat generated by a PTC heater will reduce as the sheath temperature increases. As a result, this technology requires no extra control equipment.
Split sheath cartridge heaters
Split sheath cartridge heaters reduce energy costs by maximizing heat transfer when heated. Their split sheath construction makes them easier to remove, reducing maintenance and downtime. The split sheath design also prevents bending and bowing, which is a common problem with conventional cartridge heaters. This type of heating system also offers better heat distribution with no hot or cold spots. This product also comes with slender continuous leads, which simplify wire management and offer increased flexibility.
The size of a split sheath cartridge heater depends on the size of the piece to be heated. The fit tolerance is important because it affects the efficiency of the heating process. For example, if you insert a.005″ cartridge heater into a.003″ hole, the fit tolerance is.008″. A tighter fit means a higher efficiency of heat transfer, and a longer life. On the other hand, a looser fit means more space for the heating element, which can lead to premature heater failure.
Thyristor power controls
Thyristor power controls are a great way to extend the life of high-wattage cartridge heaters. These controllers eliminate on-off cycling and allow for precise control of power. They can be used for different types of applications. Some are surface mount, while others are designed to be cemented.
Thyristor power controllers are semiconductor devices that regulate the amount of power delivered to a load. They are often used in plastic processing or industrial furnaces. They can operate with three-phase, single-phase, or alternating voltage. In some applications, they can also be used to control a transformer. These devices can also include a digital display for the output voltage.
Sealing process
A cartridge heater requires a seal to prevent moisture from egress. The heater 10 is UL-certified to operate at temperatures of up to 190 deg C. The previous-art Teflon and epoxy seals have limitations. This new seal is suitable for higher temperatures. The following steps are included in the sealing process of cartridge heaters.
Lead wires are attached to the coil before or after filling the sheath. They may be secured in place with an end plug made of silicone rubber, mica, or Teflon. The end plug is then swaged into place to complete the seal process. The lead wires may also be potted with sealants to prevent moisture from seeping into the core. Depending on the intended application of the heater, it may be necessary to make a choice in the type of sealant.