Expan

Quick fitting and removal system.

Los cartuchos calefactores expandibles solucionan dos grandes problemas de los calefactores convencionales de alta densidad , la escasa durabilidad y el ajuste adecuado de la extracción mejorando la precisión de la temperatura con cientos de enganches y salidas para todo tipo de procesos .

With expandable cartridge heaters, we combine for the first time the best of the conventional cartridge heater with a cartridge and an adaptable, quick and simple removal fitting.

Cold

Heat

Self-expanding cartridge heater

Longer life
Easy extraction.
More compact finishes.
More length without bowing.
More drilling tolerance.
No cold spots.
Hundreds of finishes and terminations.

The system

The expandable cartridge is a high-performance compressed cartridge made with top-quality materials, featuring a unique forked design tensioned at a specific point, allowing it to expand and retract on its own.

In the expansion process the expandable cartridge fits the walls of its housing, facilitating correct temperature transmission and avoiding the oven effect, which occurs in other cartridge types poorly sized relative to diameter and housing. Drills that are oversized for expandable resistors have the best solution by allowing more adjustment tolerance.

In the contraction process el cartucho expansible vuelve a su estado inicial facilitando su fácil extracción del orificio, con las conseguientes ventajas como: no tener que volver a agujerear el molde, no tener que destruir la resistencia, facilitar la limpieza del molde, reutilizar la resistencia en otras ubicaciones, reducir stock al tener un mismo diámetro para distintos agujeros, etc.

Purity of materials

Expan resistors are manufactured through an internal compaction process of all components to increase lifespan. The Nickel/Chrome 80/20 conductor wire is inserted into the cavities of a ceramic core that centers it, obtaining the ideal spacing for better insulation. All is coated with high purity magnesium oxide and controlled granularity to ensure complete filling of the Expan cartridge. Then a compaction process and surface grinding calibrate it to the desired size. Finally, it undergoes rigorous quality control to guarantee the best cartridge performance. We do not use these 4 materials: Tantalum, Tin, Gold, and Tungsten.

Nickel/Chrome 80/20 Heating Wire melting point 1400ºC
Pure magnesium oxide with controlled granulometry
Hard refractory paste
Conductive cable
Stainless steel AISI 304/316/321/ INCOLOY
Ceramic core
Hard ceramic head

Facilities and the unique construction system guarantee maximum internal purity, ensuring a longer lifespan.

Hundreds of terminations

All possible finishes for all the applications you require: submersible, anti-vibration, high temperatures, special power supply, saline or corrosive environments, compensated, etc.

The perfect companion: thermocouples

Cartridges can be built with an integrated probe at any point on the cartridge upon customer request. The advantages of including probes are numerous, for example: significantly extending cartridge life, localized temperature accuracy, energy savings, and adaptability where conventional probes cannot fit due to space constraints.

Technical Data

Voltage (V)	120 - 130 - 240 - 380 - 400
Power tolerance (w)*	+ 5 % - 10 %
Power	Depends on dimensions
Length tolerance	± 3% max 20mm
Standard diameter tolerance	-0.10 to -0.15 mm
Leakage current*	<=0.5mA at 253 V
Aislamiento*	>=5 MΩ at 500 V
High voltage resistance*	1500V to > 24V operating voltage
	500V to > 24V operating voltage
Tube material	Stainless Steel
Wire	NiCr 8020
Melting temperature	750º C

*tested at room temperature

Uniform heat

Las resistencias Expan se construyen con un solo hilo calefactor en forma de muelle, que contiene más cantidad de hilo calefactor que cualquier otro modelo de resistencia de cartucho. Con esto conseguimos un calor más uniforme por todo el perímetro, sin ninguna tipo de zona fría y sin variaciones de temperaturas.

High load compressed cartridge thermography
Different cold spots are observed, especially in the center of resistances longer than 250 mm.

Common bipartite resistance thermography
Cold spots are observed at the end of the connections, so the mold or application does not heat evenly.

Expan thermography
The absence of cold spots is clearly noticeable thanks to its exclusive construction system, which allows placing more heating wire throughout the cartridge area including connection zones.

The resistance that fits the hole

Expansion throughout the entire cartridge perimeter makes the Expan resistance the best solution for larger diameter holes caused by wear, expansion, or made with loose tolerances.

Maximum fit
Better heat transfer.

Adjustment tolerance

The fitting tolerance of the resistance is defined as the distance between the cartridge surface and the inner hole wall, which must be uniform along its entire linear perimeter.

Extraction is faster and easier, even at long lengths.

Expan resistors, due to their unique construction system, allow easy removal when the cartridge is cold, saving significant time and effort, minimizing machine downtime and human resources. No adjustment paste is needed and no drilling, destruction, or costly operations are required to remove the cartridge. You can reuse Expan resistors in other molds that need heating.

Long lengths, they will not bow, which is the main problem with conventional cartridges thanks to the tube shapes, which function to longitudinally reinforce the Expan cartridge structure, facilitating its extraction. Expanding evenly over the entire perimeter, heat transmission will be uniform without creating curves that produce cavities that overheat, causing resistance failure.

Precision in expansion

Maxiwatt expandable cartridges are designed to have the widest tolerance range of all quality heaters on the international market.

Example.
We have a 12.5D drilling with a tolerance between 12.52 and 12.48, the expandable cartridge has an actual diameter of 12.30 +/- 0.05, so we would have a maximum clearance between the cartridge surface and the hole wall of 0.37 and a minimum of 0.12, more than enough space to extract the expandable cartridge without any problems, always ensuring good contact with the entire inner surface of the hole.

All intermediate sizes in diameter and length, voltages, watt distribution, cold spots, special finishes, terminations, etc., can be manufactured.

Ø	Drilling	Ø real	Zona fría	Minimum length	Maximum length	Maximum amps according to length
3/8''	9,52 ±0,1	9,3	20	100	1000	15	15
10	10 ±0,1	9,8	20	100	1000	15	15
12	12 ±0,1	11,8	20	100	1500	25	25
12.5	12.5 ±0,1	12,3	20	100	1500	30	25
1/2''	12.7 ±0,1	12,5	20	100	1500	30	25
15	15 ±0,1	14,8	30	100	1500	40	25
5/8''	15,88 ±0,1	15,68	30	100	1500	40	25
16	16 ±0,1	15,8	30	100	1500	40	25
3/4''	19,05 ±0,1	18,85	30	100	1500	40	25
20	20 ±0,1	19,8	30	100	1500	40	25
25	25 ±0,1	24,6	30	100	1500	40	30
1''	25,4 ±0,1	25	30	100	1500	40	30

Longer useful life: the difference

The Expan resistance has more heating wire (Nickel/Chrome 80/20) than bipartite resistors or compressed cartridges with the same compression. The principle is key; the more heating wire, the larger the diameter must be for the same watts. A larger diameter reduces fatigue and wear of the heating wire, resulting in longer life.

Section of an Expan resistance with more heating wire per resistance.

Expan Bipartite
bipartida expan

Basic Bipartite
bipartida normal

Patent pending.