Some categories of hoses

Some categories of hoses

DEDUSTING, VENTILATION AND AIR CONDITIONING HOSES.

These light and very flexible hoses are produced simply using technical fabrics (such as polyester fabrics or glass fibre or Nomex/Kevlar, PVC coated, PP/EPDM, Neoprene or Silicone, just to give some examples) or plasticized PVC or Polyurethane, food and/or antistatic fabrics, connected up a spiral in harmonic steel wire attached or embedded.

They can also be externally and/or internally insulated for civil and industrial use or in naval and aerospace sectors. They are widely and in many ways used for air conditioning, refrigeration, ventilation of civil structures, tunnels, mines, orbiting stations, cabins, ships, submarines and aircraft, or wherever you need to manage with flexible structures the conveying or the transport, in positive pressure or in vacuum, air, gas (the hose must not be permeable), fumes and vapours, also in critical operating conditions, such as in presence of high temperatures, corrosive vapours or toxic gases, even with appropriate insulation. Or for the transfer of grain, dried or flour products in the food industry, the vacuum of chips in plants, trim cuts in the paper industry, splinters in the wood industry, dust in dedusting plants, air at elevated temperatures in kilns or engines; they are also used in pneumatic conveying systems, heating systems, air conditioning systems, ventilation systems, welding smoke extractors. They are used as flexible connections in rigid systems as outpouring of thermal expansion and vibration absorption points. The same kind of manufacture is used to produce dog agility paths’ hoses.

HOSES WITH THE CLAMP-PROFILE HELIX AND SEWN HOSES

This category also includes sewn or clip profile spiral hoses, or hoses made of more and more efficient technical fabrics, suitable, for example, for use at very high temperatures, even close to 1000° C. They are made from highly technical fabrics that, to be assembled, must necessarily be sewn with threads of the same fibres they consist of. Or with the original external helix structure that increases the protection of the fabric from sliding and gives greater flexibility and compressibility to this kind of hose.

PLASTIC FLEXIBLE HOSES

It’s a type of increasingly used hose thanks to its lightness, flexibility, corrosion resistance, dielectric properties, inertia against common fluids such as gas at low pressure or water. The most used materials are:

PVC (polyvinyl chloride)
PE (polyethylene)
PEX (cross-linkable polyethylene)
PP (polypropylene)
PVDF (polyvinylidene fluoride)

For their properties and efficiency they are used in the transport of drinking or drain water (sewage), food liquids, chemicals. Some of these hoses undergo ageing if exposed to sun light.
One of the factors that limit the use of these hoses is temperature; beyond certain values we advise you to use, for this purpose, rubber hoses. When subjected to large variations in temperature, hoses can undergo lengthening or shortening or softening at the expense of operational performance.
Modern production technologies allow the creation of rubber hoses with plastic substrates (those in contact with the fluid inside), to obtain one product with the best features of both solutions.

STEEL FLEXIBLE HOSES FOR USE IN PRESSURE (PED Classification)

Metal hoses for use in pressure, in accordance with the PED Classification, do not constitute a special type of hoses, but discriminate depending on: the type of fluid conveyed (danger), the hose size (mass of fluid contained) and the operating pressure, the adoption or not of additional specific certifications and rules about the quality of the material used for the hose, the compilation (made by the producer) of the processing documents containing identity and qualification of the operators who have performed significant works at the hose (for example welding) and, as for the use, certificated periodic inspections of the article (for example: detecting corrosion) in accordance with the implementing regulations.

The PED governs the design, construction, equipping and safety installation of pressure instruments. The steel tubing for these applications is fully assimilated to a “system under pressure” as a boiler or a pressurized tank. The law application provides for different levels (Categories or Classes) of certification according to the conveyed fluid, the diameter, and the pressure. The legislation also determines the conditions that are not subjected to its application (unclassified tubing).