Commonly used materials for the inner and outer adhesives of hoses include PVC (polyvinyl chloride), PUR (polyurethane), NR (natural rubber), SBR (oil-extended styrene-butadiene rubber), EPDM (ethylene propylene diene monomer), NBR (nitrile butadiene rubber/acrylonitrile), CR (chloroprene rubber/neoprene), SI (silicone rubber), UPE/XLPE (cross-linked polyethylene), and UHMWPE (ultra-high molecular weight polyethylene).
What are the tips for selecting hose assemblies?
Many factors affect the use of hose assemblies. Properly selecting hoses and fittings based on working conditions is essential to support their reliability and cost-effectiveness. These factors include:
Hose Size
The inner diameter of the hose should be appropriate. A pipe diameter that is too small will increase the flow velocity of the medium inside the pipe, thereby heating the system, reducing efficiency, and causing excessive pressure drops that affect overall system performance. If the hose is secured with clamps or routed through gaps such as steel plates, the outer diameter of the hose must also be considered.
Working Pressure
The dynamic pressure of a hose generally refers to the maximum allowable pressure during continuous operation. According to the safety factor for hydraulic hoses specified by international standards, the recommended working pressure is typically one-quarter of the hose's minimum burst pressure value.
Surge Pressure and Fatigue Life
Hose selection depends on the maximum pressure value in the hydraulic system design. Pressure values in hydraulic systems are usually dynamic, meaning surge pressures can occur, with peak surge pressures significantly exceeding the system's maximum pressure. However, since systems typically have relief valves, surge pressures do not severely affect the fatigue life of the hose. For hydraulic systems where surge pressures are particularly frequent, it is highly recommended to use hose products resistant to pulsating surges.
Temperature Range
Users must operate hoses within the temperature range allowed by the hose quality specifications. If the working environment temperature exceeds this range, the hose's lifespan will be reduced, and its pressure-bearing capacity will significantly decrease. It is recommended to use hose protective sleeves in systems where the ambient working temperature is consistently too high or too low.
Chemical Compatibility
If special hydraulic media are used, confirm that the selected hose is compatible with the medium on both its inner and outer surfaces, as well as the connectors and O-ring seals.
