They provide excellent, uniform heat distribution and are hermetically sealed, which significantly extends heater life and prevents oxidation of the heating wire even at high temperatures. Over 25,000 size options in high-density cartridges available. Maxiwatt high-density cartridges are made from premium materials and undergo the strictest safety checks in accordance with international standards.
Maxiwatt cartridge heaters Model AC are manufactured by compressing all components to extend their lifespan.
The conductor wire is wound in a spiral on a hard ceramic core into which the conductor is inserted, without a connection (although sometimes a connection may occur outside the cartridge). Ceramic discs and heads are inserted for insulation and protection. The whole is filled with verified pure magnesium oxide to ensure a completely filled cartridge. Afterwards, a compression and surface correction process is carried out until the required size is calibrated. Finally, strict quality control is performed to ensure the cartridge’s optimal performance.
The most important element in ensuring the long lifespan of the cartridge heater is the heating wire used in its manufacture. Maxiwatt uses the best available on the market. After extensive research and years of experience, it has been proven that a heating wire made from Ni-Cr 80/20 is effective and resistant to the formation of a metallic layer caused by oxidation. As the austenitic combination of nickel and chromium contains no iron, it is the most recommended for heating wires.
A nickel cable (coated with fibreglass) is used for the induction of electricity. It is coated with silicone and fireproof glazing. The wires in the cable are twisted. Sometimes, the load of the cartridge prevents the use of this type of connection. Finally, special procedures are used: threaded outlets with bolts, opposite outlets, etc. The different types of connections are shown in the protections section.
Magnesium oxide is used as an insulator and is the most suitable for isolating the heating wire and the conductor from the cartridge sheath current. When the space between the heating wire and the protective sheath is too small, an insulator is required. This must be made of the highest qualities: purity, high thermal heating level of the cartridge, maximum melting point, uniform and precise compression, perfect thermal conductivity, etc., to achieve the best insulation. Work temperature control is essential. It should never exceed the working limits of the cartridge. It is very important to store the cartridge in a dry place, as magnesium oxide is highly hygroscopic. Just a few water particles can significantly weaken its insulating capacity. The different types of connections are shown in the protections section.
The stainless steel 321 casing provides the highest quality in the manufacture of cartridge heaters. The materials that can be used in their manufacture are limited due to the stress caused by constant expansion from heating and cooling, the lack of a metallic casing (which leads to oxidation), and abrasive action. Stainless steel has proven to be the most suitable material for building cartridge heaters.
| Protective material | Stainless steel 1.4541 |
|---|---|
| Heating conductor material | NiCr 8020 |
| Max. storage temperature | 750 ºC / 1380 ºF |
| Max. voltage | 480 V |
| Power tolerance* | .+5% - 10% |
| High voltage resistance* | 1500 V AC at > 24 V operating voltage |
| 500 V at <= 24 V operating voltage | |
| Insulation resistance* | >= 5MW at 500 V DC |
| Leakage current | <= 0.5 mA at 253 V AC |
| Length tolerance | A 1.5%, min A 1mm |
| Standard diameter tolerance | metric -0.02 / -0.06 mm |
| inch: A 0.79 mils [A 0.02 mm] |
