These are the so-called lighting resistors for pellet burners, the most common of which are cartridge heaters.
Most pellet stove igniters are cartridge heaters that are designed to ignite the pellets quickly and withstand high temperatures and chemical aggressiveness of the fire. In essence, they are a type of tubular heaters that can be made of black, copper or stainless steel tube in various forms. The two outlets of the reotan protrude from one end of the pipe, and the other end is plugged by a metal plate, copper plug or silver solder. These pipes allow quality insulation of the heater from the inside. Their power is directly proportional to the length of the pipe. Cartridge igniters are easy to install and remove by placing in a special channel of the device in which they are used.
They are one of the earliest and until recently the most popular resistors for pellet burners and stoves. For their production special high-temperature ceramics are used, and the heater itself is an open type and the reotan is discovered for the most part. This makes ceramic lighters more dangerous to use and easier to burn. The same happens with careless use and contact with metal objects. Ceramic igniters use the effect of radiant heat, which heats the ambient air and thus indirectly ignites the pellets. Ceramic heaters are very efficient and economical and have almost 2 times higher temperature than traditional metal resistors. Popular types are round and flat ceramic heater.
These resistors, so-called glass heaters, are a quartz tube in which reotan is placed. They are characterized by very high heat dissipation, which is due to the fact that reotan is without insulation in the pipe and this helps to maximize heat dissipation.
Most often, quartz resistors are installed in specially designed channels in the device. Another way of installation is through additional brackets, which are thin metal plates. Quartz pipe cannot withstand structural changes in its shape, so it is available in different lengths, diameters and wall thicknesses.
The advantage of quartz heaters is that as a material quartz has a very high thermal conductivity. The disadvantage is the easy breakage of quartz igniters, so it is recommended to use them in an environment that is not subject to strong vibrations and mechanical impacts.