V našem slovníku najdete rychlé a jasné vysvětlení mnoha odborných termínů a zkratek z oblasti hadicových a spojovacích systémů. Seznam je pravidelně aktualizován a průběžně doplňován.

A

Abrasion

Unwanted alterations of the surface by separation of small particles as a result of mechanical strain. Generally known as abrasive wear. Abrasion is determined according to DIN 53516. By doing this a sample body with a particular contact pressure is guided on a turning roll covered with a testing emery sheet. The complete reaming distance is appr. 40 m. The loss of mass produced by abrasive wear is being measured in consideration of the density of the test body and the active sharpness of the testing emery sheet. It is indicated as loss of volume mm³.

Additives

All components of a plastic formulation, which are not polymers or their pre-products, and which are only added with relative small quantities (UV-stabilizers, flame protection agents, conductivity carbon black etc.).

Ageing

All chemical and physical processes ocurring irreversibly in a material in the course of time. This usually results in deterioration of the properties of use. Heat, light, high-energy radiation, chemicals, weather, oxygen (ozone) are frequent causes for ageing. The ageing condition, mostly active surface, can be pursued with the alterations of the material properties as toughness, turbidity, molecular weight, etc.

B

Bending radius

Smallest permissible radius when laying a flexible hose line. The bending radius is indicated with mm and it always refers to the inside of the hose arch.

C

Compression set

The determination of the compression set DVR [%] according to DIN 53517 is a creep test over 24 hours at 70°C and 72 hours at room temperature with constant deformation. The remaining deformation is measured after the sample has been relieved again.

Cracking resistance

Cracking resistance means the resistance, which is offered to further cracking by a notched test body. The inspection is carried out according to DIN 53515 with angle tests, which have a single-sided notch.

D

E

Elasticity

Means the ability of a material for a rebound after mechanical stress from outside has been removed.

Elastomers

Indication for wide-meshed cross-linked, macromolecular materials, which can be stretched at least for the double of their initial length by impact of a banal force at room or higher temperatures, and which return to their original form quickly and almost completely after the force has been removed.

F

Flame retardant

Are synthetic additives, which reduce the ignitability and flammability of synthetic materials. Flame retardants are able to intervene to the flammability mechanism either physically by cooling, coating or diluting, or by a chemical reaction in the vapor phase (elimination of the high-energy radicals supporting the combustion) or in the solid phase (formation of a protective carbon or ash film).

Flexibility

Required effort for the obtainment of the minimal bending radius (bigger effort results in smaller flexibility).

Flow / creeping

A deformation delayed in time but still reversible of a viscous-elastic material with constant load is indicated as creeping. An irreversible deformation occuring with higher load is indicated as flow (in cold state). The flow process results in failure of the component when the load remains unchanged.

G

Gas permeability

Flow-through of a gas through a test body. It is performed in three steps:

1. Solution of the gas in the test body.

2. Diffusion of the dissolved gas through the test body.

3. Evaporation of the gas from the test body.

The permeability coefficient is a material constant, which indicates, which gas volume flows through a test body of a known surface and thickness at a given partial pressure difference during a particular time. It is depending of temperature and it is being determined according to DIN 53 536.

H

Halogens

The elements fluorine (F), chlorine (Cl), bromine (Br) and iodine (J) are the group of the halogens.

Hardness

Hardness is the resistance of a material against the penetration of a body of a particular form and a defined elastic force. The depth of penetration is a measure for the hardness. The determination of the hardness of elastomers is carried out by Shore A or Shore D according to DIN 53505. It is indicated with an integer from 0 to 100 and the letters A and D. A higher number indicates a higher hardness.

HYP

HYP chlorosulfonated polyethylene has demonstrated its long service life under extreme conditions of use many times. It is used in a wide range of industrial applications where the demands on material properties are very high. The hoses made by Norres Baggerman with HYP coated webbing satisfy many of these demanding requirements.

The advantages of HYP are clear when exposed to high temperatures and oxidizing chemicals. The HYP coated webbings used by Norres Baggerman withstand kinking and wear, as well as destruction by the actions of weather, ultraviolet light and ozone. Moreover, HYP has excellent resistance to oil, fuel, acids and bases. On the other hand, resistance to solvents, aromatic and aliphatic hydrocarbons is only moderate.

Hydrolysis resistance

Hydrolysis = irreversible breakdown of the polyester chains with ester polyurethanes. It is caused by longer storage in warm water, saturated steam, tropic climate (humidity together with heat), aggressive chemicals or also aggressive wooden dust. The result of the hydrolysis is a decrease of the mechanic stress characteristics. Ether polyurethanes are resistant against hydrolysis.

I

J

K

L

M

Microbe resistance

Ester polyurethanes may be destroyed during a long-time contact with earth-like substances or a heavy faulting with favourable conditions for the microbes, because the chemical linkages are damaged by the enzymes released by the organisms. Very unfavourable conditions caused a first damage after 8-24 weeks. Although it is possible to delay this time by addition of toxic fungicides, the limit value required for protection may fall below by washout and dealcalization later. It is highly questionable that the often toxic fungicides are migrating inevitably to the surface and there get in contact with users or materials. These solutions do not meet our quality standards and therefore are not part of our delivery program. Our tubes of ether polyurethane are not attacked by microbes permanently and they are a better solution here obviously.

N

Neoprene

Neoprene chlorinated rubber is a very versatile, many-sided synthetic rubber that has demonstrated its outstanding properties in many industrial sectors for over 70 years. It was originally developed as an oil resistant alternative to natural rubber. Neoprene has a balanced combination of properties:

Excellent resistance to weathering, UV and ozone
Good oil and chemical resistance
Usable over a wide temperature range
Good fire behaviour

O

P

Permeation

See gas permeation.

Polyethylene

Polyethylene belongs to the polyolefin group, which includes polypropylene (PP), ethylene vinyl acetate (EVA), ethylene acrylate (AEM) and the polyolefin elastomers. The umbrella term "polyolefin" cover linear (i.e. unbranched) polymers with a carbon chain backbone that are produced by polymerization.

The polyethylene used by Norres Baggerman is extremely well suited to hose extrusion due to its particular resistance to stress cracking and good impact resistance at low temperatures. In addition to that, the walls of AIRDUC^® PE-F hoses produced by Norres Baggerman comply with the food use regulations of EU Directive 10/2011 as well as the FDA regulation 21 CFR 177.1520 (c) 3.2 (see also the appendix "Legal requirements for food contact").

Polyolefins are superior to polyurethane and PVC materials in their chemical resistance in contact with fatty substances in food (essential oils, as well animal fats and oils), most polar organic media, particularly alcohol and concentrated organic and inorganic acids and bases. Summary of key properties:

Environmentally friendly material (only carbon dioxide and water are produced during combustion)
Low resistance to mineral oils and fats, fuels and natural gas
Considerable resistance to most organic and inorganic chemicals, inorganic salts, alkalis and bases (except for oxidizing agents)
Resistant to many solvents
Low water vapour permeability, but high gas permeability
No plasticisers
Odourless and without taste

Polypropylene

This material is very similar to PE in its mechanical, electrical and optical properties as well as chemical resistance.
Very low density -> low weight (approx. 25% lighter than TPU)
High hardness and very low elongation
Good dimensional stability at high temperatures up to about +110°C
Good resistance to many media
Very low water vapour permeability, but high gas permeability

Polyurethane

As with all raw materials and finished products, there are large differences in quality for all polyurethanes commonly used on the market. Norres Baggerman uses a special ester and a special ether-polyurethane mixture for many of its hoses: Pre-PUR^®. You can find detailed information about Pre-PUR^® here.

Polyvinyl chloride - soft PVC

PVC is an amorphous plastic. Nonetheless, this material is distinguished by its outstanding media resistance. This is why PVC hoses are frequently used in applications with difficult media or environments. It is only attacked by a few solvents (aromatics, esters, ketones and chlorinated hydrocarbons).

PVC is an inexpensive, versatile material, but it does have the following disadvantages:

Its operating temperature range as well as resistance to wear are significantly less than PUR. Moreover, with flexible hoses, migration of the plasticiser can cause brittleness over time, leading to premature failure.

Today, PVC is becoming increasingly undesirable for the following reasons:

Disposal problems (PVC is classified as hazardous waste in many cases)
High clean-up costs after a fire
Many customers have issued a general prohibition against the use of PVC
Import duties on PVC products in certain countries
The plasticisers are classified as possible health hazards in some cases

PTFE (Teflon^®)

Teflon^® PTFE is a linear, completely fluorinated polymer of high molecular weight. The carbon-fluorine bonds of PTFE are extremely stable and contribute considerably to the extraordinary characteristics profile of the material. The fluorine atoms form a protective shell around the chain of carbon atoms; they shield the carbon chain from the effect of chemicals and provide outstanding chemical and thermal stability. The protective shell also reduces the surface energy and contributes to the low coefficient of friction and anti-stick (release) properties.

PTFE responds neutrally to nearly all chemicals and is neither attacked nor dissolved by organic solvents. Teflon^® PTFE contains no extractable materials that migrate and can affect nearby materials in an unfavourable manner. This is among the reasons for the physiological compatibility of PTFE. It is extremely hydrophobic and repels water almost completely. It also shows little effect from oxygen, ozone and both visible and UV light. Moreover, Teflon^® PTFE is resistant to microbes. Fluoropolymers are not attacked by fungus and bacteria.

Teflon^® PTFE is not combustible for the most part (UL 94: 94 V0). Due to its high melt viscosity, PTFE does not drip if it is heated above its melting point. Its flame propagation and heat dissipation are extremely low.

PTFE has extremely low friction coefficients. Because of its low surface energy, PTFE demonstrates excellent anti-stick properties and thus prevents encrustation of all kinds.

Teflon^® PTFE is extremely stable at high temperatures. Its constant use temperature is around 260°C. Moreover, it is one of the few polymers to retain a certain durability and strength at extreme low temperatures.

Teflon^® is a registered trademark of DuPont.

Q

R

S

Silicone

Silicone rubber belongs to the class of materials known as silicones, whose backbone structure is composed of extremely stable silicone-oxygen chains, referred to as polysiloxane chains. This structure gives silicone rubber particularly advantageous properties compared to other elastomers, including outstanding resistance to heat, cold, weathering, ozone and oxidation. It has only moderate resistance to oil, fuel, acids and solvents and poor resistance to aromatic and aliphatic hydrocarbons. The mechanical properties are relatively constant over the entire temperature range.

Surface resistance

The surface resistance (Ro) indicates the insulating ability of the insulator surface. Ro is reduced with synthetic materials by the formation of a water skin, which results from the effect of hydrophilic groups (-COOH, -NH2, -OH), plasticizers and organic extenders. Ro is determined with a test voltage of 1 kV between two electrodes at a distance of 10 mm (resilient metal edges). Ro is either indicated in Ohm or as a reference number, e.g. 10 = Ro < 10 or reference number 6; 10 = Ro < 10 or reference number 11.

Swelling

Absorption of liquid and gaseous materials in solids, without any chemical reaction takes place between them. The result is an increase in volume and weight together with a corresponding decrease of the mechanic values. After the penetrated material has been vaporated and the decrease of the swelling caused by this the original characteristics of the product are nearly reached again. Swelling is therefore a reversible process.

T

U

UV radiation

According to duration and intensity, synthetic materials can be broken down chemically by the action of UV radiation (aging). Polyurethanes have generally a good UV resistance. In the course of time there is a yellowing of the material, what does not automatically cause a decrease of the mechanic property values. With the help of UV stabilizers and/or by colour pigmentation a particular stabilization can be accomplished. We offer special hose solutions for increased and high UV exposure. Please contact us in such cases.

V

Vertex compressive strength

Resistance against the compressing of exhausting and pressure hoses by outside load found in the vertex.

Viton^®

Viton^® has proven its worth through years of field use under extreme environmental conditions – the best credentials to satisfy your most demanding applications.

In many applications hoses are exposed not only to brief temperature spikes but also higher temperatures of use. Depending on the task, Viton^® can handle constant use temperatures as high as 205°C and has excellent resistance to many aggressive fluids. It has excellent resistance to aromatic and aliphatic hydrocarbons, moderate resistance to bases and poor resistance to solvents. Viton^® has outstanding resistance to atmospheric oxidation, sunlight and ozone. Viton^® also has very low permeability to gases.

Viton^® is a registered trademark of DuPont.

Volume resistivity

According to TRGS 727 volume resistivity R_GES = R×A/S[Ω×m] must be determined. Where R is the measured resistance, A is the lateral surface of the electrode and S is the reed thickness between plastic and wire.

A piece of hose with a length of 100mm is measured by a unilaterally inserted cylindrical electrode, where the counter electrode is forming the steel wire helix. The thus determined volume resistivity must be R_GES < 2,5×10⁸ Ω×m.

Vulcanised thermoplastic elastomers (TPE-V)

The hoses made by Norres Baggerman that are labelled TPE (or TPE-V) are hoses manufactured from a thermoplastic rubber. This completely vulcanised polyolefin material belongs to a group of elastomers which provide an excellent combination of the performance characteristics of vulcanised rubber, such as thermal resistance and low compression set, with the superior processing characteristics of thermoplastics. The manufacture involves a special dynamic vulcanization process, which produces fully networked rubber particles distributed in a continuous matrix of thermoplastic material. The rubber particle size of a micron or less results in excellent physical properties for the material.

TPE-V has a resistance to environmental influences corresponding to that of standard EPDM rubber mixtures, whereas the chemical resistance is comparable to chloroprene rubber mixtures.

The thermoplastic rubber used by Norres Baggerman has excellent resistance to heat aging and maintains its tensile properties after prolonged exposure to high temperature better than most vulcanisable rubbers.

Summary of key properties:

Temperature range -40°C to +125°C (150°C):
The brittle point is at about -60°C
Outstanding hot air aging behaviour at temperatures up to 150°C for periods up to two weeks and for longer periods at up to 125°C
Good resistance to aqueous solutions, dilute acids and bases, organic solvents, mineral oils and grease and antifreeze
Very good resistance to ozone and weathering
Mechanical strength similar to PVC
Very good dynamic fatigue strength and good damping ability

W

Water vapour permeability

It is indicated by the quabtity of water vapour, which is running through 1 m² test surface, and it is approximately inversely proportional to the test thickness. The water vapour permeability WDD in g/(m²*d) of a synthetic material is determined according to DIN 53122 sheet 1.

Náš slovníček: přehled technických termínů a zkratek

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