A free Quick Reference Safety Guide is now available from Denver-based Gates Corp. The handy reference outlines preventive maintenance practices and offers safety tips for anyone working with and around hydraulic hoses and couplings—including machine operators, service technicians and even equipment designers.
According to the company, Gates experts created the Guide to help improve hydraulic hose assembly safety, and it includes tips on how to improve the overall safety of hydraulic hose and couplings and procedures that improve preventive maintenance.
The Safety Guide starts by discussing periodic inspection procedures. Users should disable and lock out the equipment’s power, remove access panels, and inspect hoses and fittings for damage and leaks—and, of course, repair or replace assemblies as needed. In addition, inspect other hydraulic components at the same time. After inspection, replace the panels, turn the power back on and note if there are any unusual noises, vibrations, or other defects during operation.
For assistance with hose-assembly troubleshooting, the guide explains (and includes helpful photos and graphics) some obvious signs of damage or distress. These include:
Abrasion, where part of the hose cover rubs away by contact/friction with other equipment components, hoses or other objects in the working environment.
Cover blisters, caused by incompatible ﬂuids, compressed gasses and trapped air that can permeate hoses underneath the hose cover.
Leaks, which result from missing or damaged O-rings, damaged threads or seat angles, thread misalignment, incompatible parts, or over- or under-torqueing the connections.
Hose cracks. Hose covers or tubes can exhibit cracks or appear hardened when they fail to stand up to excessive heat, extreme temperatures or other harsh conditions.
The guide also offers some helpful hose installation tips. For instance, to avoid hose collapse and ﬂow restrictions, keep the hose and bend radius as large as possible. Users should refer to hose speciﬁcation tables for minimum bend radius recommendations. Also prevent twisting and distortion by bending the hose in the same plane as the motion of the port to which the hose is connected.
When installing new hoses or inspecting existing ones, ensure the hose is properly routed. Use recommended angle adapters to avoid tight bends in the hose. And avoid sources of extreme heat. High ambient temperatures shorten hose life. If mounting hose away from hot parts is not possible, either reroute the hose or insulate with protective sleeving.
Among other tips for proper routing, when installing hose in straight directions, allow enough slack in the hose line for length changes that occur when pressure is applied. And use elbows and adapters to relieve strain on the assembly and to provide neater installations for more accessible inspection and maintenance.
The Guide includes some useful advice to ensure proper installation. For example, it shows torque tables for various sizes of fittings like JIC 37°, SAE 45° and Gates MegaSeal couplings in steel and brass, as well as flat-face O-ring seal, SAE O-ring boss, and Gates Adapterless products for a range of pressures.
It also discusses the “flats” method of verifying coupling torque. Here, a table and instructions relate how to mark the coupling’s backup hex, nut and adapter hex when hand tight, and then further tighten until the mark is displaced a predetermined amount.
Finally, the Guide offers helpful, everyday information such as various metric-to-psi pressure conversions. And a dash-size chart relates the thread size for different fitting styles, given the dash size and nominal size. It includes NPTF pipe, O-ring boss, JIC 37° flare, SAE 45° flare, O-ring flat face, inverted flare, and Code 61 ad 62 flange-head OD.