Hydraulic Hose System Design
- Feb 07, 2018 -
Hydraulic hose must match the highest pressure capable in a hydraulic system, which is typically the pressure the pump provides. However, there can certainly be pressure increasing components in machines that can go much higher than the hydraulic relief or a pump pressure capacity, especially when a pressure intensifying cylinder is flow generated. Special attention must apply when designing systems with geared flow dividers because of this effect.
Hoses usually have a burst rating of 4 times the pressure rating so although a lower rated hose can work for a short time, they will fatigue and then fail in a shorter time. It’s a good idea to then look at the failed hose to make sure it will match the hydraulic flow circuit pressure ratings. Sometimes people can simply make a hydraulic hose assembly from the wrong type of hose and won’t realize it only until failure. This can happen even from the factory.
High pressure hydraulic lines for mobile equipment usually come in a few number of pressure ranges. There are exceptions to this, especially with hose manufacturers trying to crack into market share by offering different benefits to their customer. 6000 psi pressure rated hydraulic hose can be typically found on closed loop hydro-static circuits such as trackground drives and higher horsepower drives used on drillers, trenching equipment, etc.
Next, there is the 4000-psi hose that is used on some of the open loop piston pumping systems involved in manufacturing. The most common hydraulic hose found in industry is the 3000 psi rated hose, which is common with gear pumping circuits used in correlation with high pressure cylinders and gear motor systems. There are many hoses 1500 and lower psi ratings for the return lines and other special case applications. Most of these hydraulic hose lines are used to supply the valves and then return back to oil coolers, hydraulic filters, and the oil reservoir. If you wonder, why not use the highest pressure hydraulic hose on everything in an oil circuit; it’s because of the higher cost.
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