Insulation tubes with various protective and insulation functions

15.05.2019 - Similar to spirally wound caps insulation tubes manufactured from films are used in a number of industrial fields. Due to the combination of different materials the areas of application are widely spread and range from electrical insulation of components, noise reduction and moisture protection to chemical as well as thermal protection for individual items or cables. Application examples are: PTC sensors, capacitors, industrial sensors, thermistors.

Polifibra Folien GmbH provides suitable and custom-made insulation tubes for different applications. Tubes and sleeves are manufactured to required dimensions according to customer needs and delivered as general cargo (break bulk). Besides spirally wound and flat tubes we manufacture shrink-tubing for special applications.

Raw materials used include: Nomex® (by Dupont), fleece, polyester film, heat-shrunk film made of polyester HS, semi-shrunk film made of polyester AHS or polyimide film. Correctly configured tubes may be used within a temperature range of -60 to +300 °C. Customers may choose from thicknesses between 0.05 to 0.8 mm, diameters between 1.78 to 150 mm and length between 6.6 and 14,000 mm. For better identification tubes - or their edges- may be colour dyed. All raw materials are UL-certified and offer excellent electrical, chemical and vicinity insulation. Adhesives used in all products fully comply with REACH- and RoHS-regulation and ensure full retention of original properties.

Please find below an overview, including details and advantages, of each type of tube:

Spirally wound tubes

This tube is manufactured by a winding technique in which bands are spirally wound round a winding mandrel. Spirally wound tubes can be used in almost any application and area.

Flat tubes

Flat tubes are manufactured from base films and, without compromising its puncture resistance, a slight overlap. An additional advantage here is the fact that flat tubes may be coiled and delivered on rolls or spools thereby providing the essential pre-requisite for use in automated production. This type of tube is predominantly utilised in connection with different components such as stranded wires in electric motors and compressors, but also for the insulation of busbar trunking systems.

Special applications

Shrink-tubes for secure hold of permanent magnets in brushless motors

In co-operation with its partners Polifibra developed various spirally wound tubes - made of heat-shrunk polyester film in order to hold rotor magnets in place. Such shrink-tubing may, besides traditional heat-shrunk polyester film, additionally be supplemented with fibreglass, Nomex® as well as epoxy resin. Thereby ensuring solid adherence of magnets on the rotor. The tube has, after being heat-shrunk, no negative impact on the magnet gab and magnetic flux of the motor. Besides holding magnets in place shrink-tubing can, amongst other things, also be utilised to reduce noise or protect against contamination.

Shrink-tubes for rotors of universal motors of washing machines

Polifibra offers solutions, similar to shrink-tubing for brushless motors, for universal motors of washing machines. Again the shrink-tubing used here is manufactured of heat-shrunk polyester film. Its objective is to protect rotor magnets against dust und to compress the rotor surfaces at the slots thereby reducing the noise level by a few decibels. Thanks to full automation of the insertion process and immediate heat-shrinking of the tube on the rotor the product is perfect for use in automated production processes. Shrink-tubing is available in thickness between 50 and 100µ; and delivered on rolls with a length of several hundred metres each, making logistics and transportation more economical which, in turn, reduces cost. Again the tube has no negative effect on the magnet gab and the magnetic flux of the motor after being heat-shrunk.

Protective sleeves for fridge coils

In addition Polifibra offers a broad range of tubes made of heat-shrinkable polyester for the protection of fridge coils. Spirally wound and flat tubes are suitable protective sleeves. The advantages lie in the adjustability of the tube to fit the shape of the coil, speed of positioning and ease of heat-shrinking. Furthermore, the tubes provide excellent mechanical resistance, long service life, the highest level of protection against condensation as well as a lower space requirement due to its flat design. As such tubes are usually transparent, a simple visual inspection as to the state of the coils may be conducted. Tubes are available with a diameter of 4 up to 25 mm, with thicknesses of 75 to 160µ, in customized length but also on rolls with a length of several hundred metres each, making logistics and transportation more economical which, in turn, reduces cost.

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