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Cartridges with high charge watts.
They provide a great uniform distribution of heat, and are made hermetically, which considerably increases the long life of the resistance as well as preventing the oxidation of the heater wire even at high temperatures. Over 8000 measurements in high density.
High charge Maxiwatt cartridges are made from prime quality materials and undergo the strictest control for safety, clompying with international standards.

 Long-life
 High temperatures
 Variety of terminations
 Maximum watts capacity 60w/cm2
 Wide 24 horas permanent stock

Internal complements

Termocouple Watt distribution Inactive Areas Different voltages

Technical data

Heat intensity Not exceeding 40Wcm2 (advisable) Power Depends on the dimension Escape of current (when cold) <=0.1mA a 242 v. Insulation (when cold) 5 Min Ohmios 500 Watts minimum Dielectric strength 1500v. 1/seg Working temperature 750ºG max. Tolerance of length +/-1.5% Tolerance of diameter -0.01 a -0.06 m/m Tolerance of cut of connexion +/-15 mlm Power tolerance (w) + 5 % - 10 % Cold areas Depends on length and diameter 5-25mm

Manufacture
Durawatt cartridge heaters are made of means of compression for all their components, with the aim of lengthlening their working life.
The conductor wire is wound round the hard ceramic body into which the conductor lead is inserted, with no connexion (sometimes, a connexion may occur on the outside of the cartridge). Ceramic discs and heads are inserted to obtain insulation and protection. Everything is coated with checked pure granulometric magnesium oxide to ensure total completion.
Later a process of compression and another of rectificatifying the surface is carried out until the required measurement is calibrated. Finally, a strict quality control is carried out to guarantee the best working of the cartridge.

Welded watertight base (Tig) to withstand pressure up to 60 kg/cm2. Calibrated stainless steel AISI 304/316/321/ INCOLOY. Ceramic disc insulator. Checked pure granulometric magnesium oxide. Nickel-chromium 80/20 heater wire. Melting point 1400º C. Ceramic core. Hard ceramic head. Conductor lead. Hard refracting paste. Conductor without connexions.

The unique system of Maxiwatt manufacture makes perfect concentricity possible and together with its electronic system of the space between the spirals quarantees the same temperature for the whole perimeter and length of the cartridge, thereby obtaining a uniform and lasting temperature.

 Use
They are able to withstand the toughest working conditions, such as vibration, moisture, fluid, spills, frequent expansion and where temperatures of between 400ºC and 750ºC are required, or temperatures within a limited space.

 Applications
Moulds
Smelting of materials
Heating of fluids
Heat welding, etc

When solids, gases and fluids are to be heated by elecric energy the process is generally carried out by conduction. It is only possible to transmit heat quickly by conduction if the producer of the heat (the cartridge) is in direct contact with the receiver of the heat (any solid, gas or fluid).
When heating takes place the molecules expand and move faster, producing a distribution of heat to the colder part until their temperatures level out.
If there is mould on which to drill in order to house a cartridge heater, and where the mould not to be in direct contact with the whole cartridge heater, the transmission of heat by conduction would occur, due to the fact the air molecules would not transmit the energy required to heat the mould. The heat would not be distributed but would remain within the cartridge heater, with the result of overheating of the latter, which, in turn, may bring about a reduction of dielectric strength between the heater wire, the power conductors and the weakening of the metallic protector, the result being a shortcircuit. Therefore, the adjustment of the cartridge to the heater is of the most importance.

Power
When working with high-density cartridge heaters, the exact amount of the power required must be noted for correct functioning as well as for the useful life of the cartridge heater.
Maxiwatt cartridge heaters are designed in a way that takes into account the natural ageing of the performance of the heater wire and its nature, coinciding with the nominal power of the cartridge heater.
The concurrence of the real power with the nominal power takes place through a selective process which only chooses those cartridge heaters having a power tolerance corresponding to 7% of the nominal power.

	Powe at,	Cold state	Hot State	Power at,
D. Y Long.	230 V.	Ohms Value	Ohms Value	230V.	Variation
10x80	315 W	167,94	174,15	303.76 W	-3,7
10x100	400 W	132,25	136,34	388.00 W	-3,1
10x130	500 W	105,80	108,55	487.33 W	-2,6
12.5x80	400 W	132,25	136,21	388.37 W	-3
12.5x100	500 W	105,80	108,02	489.72 W	-2,1
12.5x130	800 W	66,13	67,32	785.80 W	-1,8
16x80	630 W	83,97	85,64	617.97 W	-2
16x100	1000 W	52,90	53,69	985.29 W	-1,5
16x130	1100 W	48,09	48,52	1090.27 W	-0,9
20x100	1000 W	52,90	53,44	989.90 W	-1
20x130	1250 W	42,32	62,65	1240.33 W	-0,8

Stainless steel 321: cover
The stainless steel 321 cover provides the highest quality to the manufacture of cartridge heaters. The materials which can be used in their manufacture are limited due to the strain caused by constant expansion owing to the cooling and heating of the cartridge heater, the lack of a metal cover, which causes oxidation, and abrasive action. Stainless steel has been shown to be the most suitable material for the construction of cartridge heaters.

Total insulation
Magnesium oxide is used for insulation, and is the most suitable for insulating the heater wire and the conductor lead against the current of the sheath of the cartridge. When the space between the heater wire and the protecting sheath is too short, an insulator is required, which should be composed of the best qualities: purity, high degree of thermic cartridge heater, maximum melting point, uniform and exact compression, perfect thermic conductivity, etc, so that the best insulation is obtained.
Control of the working temperature is fundamental. It must never exceed the working limits of the cartridge. It is of paramount importance to store the cartridge in a dry space because magnesium oxide is very hygroscopic. Just a few drops of water particles are enough to weaken considerably the insulating capacity of magnesium oxide.

Ni-Cr 80/20 heater wire
The most important element for ensuring the long life of the cartridge heater is the heater wire used in its manufacture. Maxiwatt use the best to be found anywhere in the market. After extensive research and years of experience it has been shown that a heater wire made of Ni-Cr 80/20 is both efficient and resistant to the formation of metallic coating brought at out by oxidation. As the austenitil combination of nickel and chromium lacks iron, it is the most suitable for the heater wire.

Conductor lead
For the induction of electricity a nickel cable (shealthed by glass fibre) is used. It is coated with silicone and fire-proof glazing. The cable wires are turned. Sometimes, the charge of the cartridge prevents the use of this type of connexion. To the end, special procedures are used: threaded outlets with bolts, opposite outlets, etc.
The different types of connexion are shown on protections section