Page 474 - 2019 Product Technical Manual
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3.10 Minimum Bend Radius: Installation of a hose at less than the minimum listed bend radius may significantly reduce hose life.
3.11 Twist Angle and Orientation: Hose installations must be such that relative motion of machine components does not produce twisting.
3.12 Securement: In many applications, it may be necessary to restrain, protect, or guide the hose to protect it from damage. Care must be taken to ensure such restraints do not introduce additional stress or wear points.
3.13 Proper Connection of Ports: Proper physical installation of the hose requires a correctly installed port connection while ensuring that no twist or torque is transferred to the hose.
3.14 Assembly Torque: The correct torque instructions and specifications must be followed to obtain a proper seal when a hose assembly is attached to a port, an adaptor or another assembly.
3.15 External Damage: Proper installation is not complete without ensuring that tensile loads, side loads, kinking, flattening, potential abrasion, thread damage, or damage to sealing surfaces are corrected or eliminated. See instruction 2.10.
3.11 System Check-out: After completing the installation, all air entrapment must be eliminated and the system pressurised to the maximum system pressure and checked for proper function and freedom from leaks. NOTE: Avoid potential hazardous areas while testing.
3.12 Minimum Free Length of Hose Assemblies: Occasionally requests or orders arise for hydraulic hose assemblies where the ‘Free Length’ of hose between the ferrules of the couplings is not long enough, and could hinder the ability of
the hose assembly to function properly. This is particularly the case when utilising very short hose assemblies, where
a shortening or shrinkage of the hose under pressure may result in hose and coupling separation. In addition, small misalignments, vibration and other displacements may induce very high stresses upon the hose/coupling juncture, as there is little capacity for the flexible nature of the hose to compensate.
Due to the possible problems associated with using very short hose assemblies, RYCO has adopted the following general rule (equation) for the allowable Minimum Free Length (MFL) of hose to be used as a guide when fabricating or ordering a hydraulic hose assembly.
Should the Minimum Free Length (MFL) of the actual
hose assembly fall below the derived MFL value from the above equation (when calculated using information for the relevant hose size from the relevant, and most current, hose specification), RYCO CAUTIONS the hose assembly as being “under recommended Minimum Free Length – may cause premature hose assembly failure”.
Even with proper selection and installation, hose life may be significantly reduced without a continuing maintenance program. Frequency should be determined by the severity of the application and risk potential. A maintenance program must include the following as a minimum.
4.1 Visual Inspection Hose/Fitting: Any of the following conditions require immediate system shut down and replacement of the hose assembly:
• Slippage or movement of fittings on the hose
• Damaged, cut or abraded cover
• Hard, stiff, heat cracked, or charred hose
• Cracked, damaged, or badly corroded fittings
• Leaks at fitting or in hose
• Kinked, crushed, flattened or twisted hose
• Blistered, soft, degraded or loose cover
• Unusual noise, odour or heat.
4.2 Visual Inspection All Other: The following items must be tightened, repaired or replaced as required:
• Leaking port conditions
• Remove excess dirt build-up
• Clamps, guards, shields
• System fluid level, fluid type and any air entrapment
4.3 Functional Test: Operate the system at maximum operating pressure and check for possible malfunctions and freedom from leaks.
4.4 Replacement Intervals: Specific replacement intervals must be considered based on previous service life, government or industry recommendations. See instructions 1.2.
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