The materials commonly used for the inner and outer layers 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), 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?
There are many factors that affect the use of hose assemblies. Correctly selecting the hose and fittings according to the working conditions is essential to ensure the reliability and economy of the hose. These factors include:
Hose Size
The inner diameter of the hose should be appropriate. If the inner diameter is too small, it will increase the flow velocity of the medium inside the hose, thereby heating up the system, reducing efficiency, and causing excessive pressure drops, which will negatively affect the overall system performance. If the hose is secured with clamps or passes through gaps such as steel plates, the outer diameter of the hose must also be taken into consideration.
Working Pressure
The dynamic pressure of a hose generally refers to the maximum allowable pressure during continuous operation. According to the safety factors for hydraulic hoses specified by international standards, the recommended working pressure is typically one-quarter of the hose's minimum burst pressure value.
Shock Pressure and Fatigue Life
Hose selection depends on the maximum pressure value in the hydraulic system design. The pressure in hydraulic systems is usually dynamic, meaning shock pressures may occur, with peak values significantly higher than the system's maximum pressure. However, since systems are typically equipped with relief valves, shock pressures do not severely affect the fatigue life of the hose. For hydraulic systems that experience particularly frequent shock pressures, it is highly recommended to use hose products with high resistance to pulsating impacts.
Temperature Range
Users must operate the hose within the temperature range allowed by its quality specifications. If the working environment temperature exceeds this range, it will shorten the hose's service life and significantly reduce its pressure-bearing capacity. 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, ensure that the selected hose (both inner and outer layers), the connectors, and the O-ring seals are all compatible with the medium.