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- Home /
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FAQ
In this FAQ section, you will find technical questions and expert answers covering industrial hose technology. The content supports the safe selection, standards-compliant use, and understanding of technical requirements in industrial applications. This knowledge library is continuously expanded and reflects current challenges and practical questions from the field.
Electrical conductivity protects against electrostatic charge buildup that can occur when conveying alcoholic or highly flammable food products or pharmaceutical media. This increases operational safety and helps prevent potential ignition sources within the process.
The FoodPharm UPE SD hose, with its white UPE liner, is designed for pharmaceutical and food industry applications. To safely dissipate electrostatic charges, black conductive stripes made of electrically conductive material are seamlessly integrated into the hose liner.
The service life of a hose assembly depends on operating conditions and the level of care with which it is handled. Therefore, its lifespan can vary significantly and cannot be precisely defined.
It is the operator's responsibility to determine inspection and replacement intervals. As a general recommendation, at least one annual inspection should be carried out as part of a recurring safety inspection.
During the transfer of media through a hose assembly, it cannot be completely ruled out that particles from the hose wall may be released. For this reason, food-grade hoses often feature white liners to prevent visible discoloration or contamination of the final product.
Additionally, the hose assembly must comply with the relevant food industry regulations and standards.
For temperatures above 80°C, a PESC braid is recommended. It is suitable for continuous operation up to 230°C.
Electrical conductivity is achieved through integrated stainless steel fibers (4 to 8 strands of grade 1.4404 stainless steel). As a result, the PESC braid is also suitable for use in hazardous areas classified as Zone 0.
Powder conveying applications require both antistatic properties and high abrasion resistance.
PU (polyurethane) is widely used because its relatively high hardness provides excellent resistance to abrasive wear. In addition, PU hoses are highly flexible and typically transparent, making blockages or material build-up easier to detect during operation.
There are various materials used for hose cores:
- NBR cores (nitrile rubber): suitable for mineral oils, diesel, gasoline (up to approx. 50% aromatics / special additives);
general-purpose applications; color: black. - UPE liner: suitable for chemicals, corrosive acids, alkalis, and solvents; color: typically black.
- PTFE liner: suitable for nearly all chemicals as well as for pharmaceutical, food, and cleanroom applications; suitable for high temperatures.
- NR core (natural rubber): suitable for dairy products, food transport; color: usually white.
- Silicone core: suitable for pharmaceutical products, cosmetics, and biotechnology; color: usually white/transparent.
- FEP core (fluoroethylene-propylene): suitable for conductive, aggressive chemicals; color: white.
NBR (Nitrile Rubber)
Suitable for:
- Mineral oils
- Diesel
- Gasoline (up to approx. 50% aromatics and special additives)
- General industrial media
Typical color: Black
UPE (Ultra High Molecular Weight Polyethylene)
Suitable for:
- Chemicals
- Aggressive acids
- Alkalis
- Solvents
Typical color: Black
PTFE
Suitable for:
- Almost all chemicals
- Pharmaceutical applications
- Food applications
- Cleanroom environments
- High-temperature processes
NR (Natural Rubber)
Suitable for:
- Dairy products
- Food transportation
- Typical color: White
Silicone
Suitable for:
- Pharmaceutical products
- Cosmetics
- Biotechnology applications
- Typical color: White or transparent
FEP (Fluorinated Ethylene Propylene)
Suitable for:
- Conductive aggressive chemicals
Typical color: White
Sliding Abrasion
Sliding abrasion occurs when particles move parallel to the hose wall and gradually wear away the surface.
Typical applications:
- Pneumatic conveying
- Pressure conveying
- Metal granulates
- Silicates
Key material requirement:
- High surface hardness
- Smooth surface
Suitable hose materials:
- PE
- PP
- TPE
- UPE (UHMWPE)
UPE offers the highest abrasion resistance for sliding abrasion applications. Markert Marsoflex exclusively uses high-density UHMWPE with a molecular weight of approximately 5 million g/mol.
Impact Abrasion
Impact abrasion occurs when particles strike the hose wall at an angle or directly, causing localized material removal.
Typical applications:
- Slurry transport
- Mining operations
- Concrete transport
- Gravel and ore conveying
Key material requirement:
- High elasticity
- High energy absorption
Suitable hose materials:
- SBR
- NBR
- NR (Natural Rubber)
NR provides the highest resistance to impact abrasion. Markert Marsoflex uses NR compounds optimized for rebound elasticity.
The bend radius is the smallest radius a hose can be bent to without sustaining damage.
If the specified bend radius is exceeded, the hose may kink, resulting in a significant reduction in service life.
The bend radius does not indicate how much force is required to bend the hose. Hoses with a corrugated outer surface generally require less bending force and are therefore considered more flexible. However, this flexibility refers to bending force, not necessarily to a smaller bend radius.
Extractables and Leachables (E&L) studies are required when a material comes into contact with pharmaceutical products or process-critical media and there is a risk that chemical substances may migrate from the material into the product.
Extractables Studies
Identify which chemical substances can be extracted from a material under worst-case conditions, typically using aggressive solvents.
Leachables Studies
Investigate which substances actually migrate into a product under real operating conditions, considering:
- Process media
- Exposure time
- Temperature
- pH value
The result determines which substances migrate into the product, in what concentrations, and whether they pose a risk to product quality or patient safety.
Breakaway couplings are used when damage may occur due to vehicle movement, snagging, or accidental pull-away situations, such as when a tanker leaves a loading station without disconnecting the hose.
This is particularly critical when handling hazardous or environmentally harmful media in the chemical and petrochemical industries.
A breakaway coupling automatically separates at a predefined tensile load and simultaneously closes both sides of the connection.
Mechanical breakaway couplings close immediately during separation, preventing media leakage. Alternatively, safety-break couplings use a predetermined breaking element while integrated check valves shut off the flow.
Halar® is an ECTFE (Ethylene Chlorotrifluoroethylene) coating known for its exceptional chemical resistance.
Such coatings can reduce the need for expensive specialty alloys such as Hastelloy.
However, coating thickness is limited to approximately 0.3 mm, making it more susceptible to mechanical damage. A more robust solution is often the use of PTFE- or PFA-lined fittings.
A Kamvalok coupling is a dry-disconnected coupling manufactured by OPW (USA). Kamvalok is a registered trademark.
The coupling uses an internal valve mechanism operated manually via an external lever. This allows the valve to be opened and closed as required.
When closed, the coupling enables connection and disconnection without product loss, making it a true dry-disconnect system.
Dry-disconnect couplings prevent product leakage during connection and disconnection.
They operate through valves that remain open when connected for product transfer and automatically close when disconnected, preventing media release on both the plant and hose sides.
The NATO standard STANAG 3756 is a military fuel handling and interface standard primarily applied in petrochemical environments. It requires a non-spill or dry-break principle during fuel transfer operations.
The standard also specifies design requirements such as:
- Nominal sizes
- Operating pressures
- Locking mechanisms
- Functional principles
These requirements ensure general mechanical compatibility between couplings from different manufacturers. However, differences in flow performance, sealing characteristics, operating forces, and wear behavior may still occur.