Hydraulic hose

Hydraulic hose is a common and important element in countless industrial and mobile machines. It serves as the plumbing that routes hydraulic fluid between tanks, pumps, valves, cylinders and other fluid-power components. Plus, hose is generally straight forward to route and install, and it absorbs vibration and dampens noise. Hose assemblies — hosewith couplings attached to the ends — are relatively simple to make. And if specified properly and not overly abused, hose can work trouble-free for hundreds of thousands of pressure cycles.

Hydraulic hoses often consist of an inner tube, one or more layers of reinforcement, and an outer cover. Each constituent should be selected with the intended application in mind. Typical operating and performance parameters include the size, temperature, fluid type, pressure-holding capacity and environment, to name a few.

Reinforced hose is constructed with some structural element — styles include spiral wire, textile braid, wire braid, wire helix and other designs in many plies or layered configurations. The inner tube contains the fluid and keeps it from leaking to the outside. The cover protects the reinforcement layer.

Image courtesy of Kuriyama

Other construction options for hydraulic hose include coiled, corrugated or convoluted. Coiled hose is designed for flexibility and elasticity. This feature often makes it expandable and easy to store. Corrugated hose contains corrugations, pleats or spiral convolutions to increase flexibility and capacity for compression and elongation. Multi-element hydraulic hoses are constructed of more than one hose formed or adhered together in a flat, ribbon or bundled configuration. Additional features to consider include whether the hose requires integral end connections, anti-static, lay flat, crush-proof and flame-resistance characteristics.

In addition, material considerations include the type of fluid being conveyed and its concentration, as well as substances that may attack the hose cover. Hose selection must ensure compatibility if it is to convey special oils or chemicals. The same holds for hose exposed to harsh environments. Substances such as UV light, ozone, saltwater, chemicals and pollutants can cause degradation and premature failure. For in-depth fluid compatibility data, consult the manufacturer.

Image courtesy of Gates

While hydraulic hose is usually constructed of multiple materials, the most commonly used primary materials include elastomers, fluoropolymers and silicone, thermoplastics, metal, and composite or laminated structures. Elastomeric or rubber hydraulic hose are often selected for their flexibility. Fluoropolymer hose offer good flex life, superior chemical and corrosion resistance and can handle high temperatures. Thermoplastic hydraulic hose offers tight minimum bend radii and excellent kink resistance. Metal hoses can handle high temperature flow materials and often can handle higher pressures. They can be either stiff or flexible.

Flexible hoses are easier to route and install, compared with rigid tubing and pipe. They lessen vibration and noise, dampen pressure surges and permit movement between parts. In addition, increasing demands for higher productivity, efficiency and environmental compatibility are forcing hose manufacturers to improve product integrity — hoses now withstand higher pressures, extreme heat and cold and accommodate a range of fluids including today’s “green” variants.

Most hoses are manufactured to SAE J517, European Norm (EN) or ISO Standards. These standards predominate in the Americas, Europe and Australia, and are also used throughout Asia.

HYDRAULIC HOSE EXPERTISE HELPS A CUSTOMER FULFILL HIS GREEN-LIVING DREAM

Image courtesy of Power Drives Inc.

Power Drives Inc., a manufacturer and distributor specializing in fluid transference and filtration, was faced with a unique challenge when a customer came into one of their Express Hose Centers with the intention of fully restoring a 1960 Case 430 backhoe loader.

The customer was looking to bring the tractor back to its former shape and condition — in order to use it to start and cultivate a greenhouse operation. He started researching options, to determine what was required for the project, and experienced difficulty finding such information for a restoration of this scope, as the original Case Corp. no longer exists. The tractor clearly needed a lot of work, and he pored over what information he could find; it was immediately clear that he had to completely rebuild the frame and engine, as well as replace all of the hydraulic hoses.

The damaged hydraulic hoses were brought to the PDI team at their Tonawanda, N.Y. Express Hose Center, where they identified each hose and fitting, taking into account the pressure ratings and internal structures, in order to replicate 18 new hydraulic hose assemblies. The expertise of the Eaton Aeroquip-certified technicians allowed for a quick turnaround on this order. Additionally, the customer took care to ask for added hose protectors, to help preserve his new investment.

After completing the restoration and installing all of the new hoses, the 1960 tractor now runs like it is brand new. Not only is the tractor a sight to behold once again, but it is helping this loyal PDI customer fulfill his dream of creating and maintaining a selfsustaining greenhouse, which will produce both heat and electricity. Now he has a reliable machine for decades to come.

Restoring agricultural machinery — especially machinery that is no longer produced — can sometimes feel like a heavy burden. In this case, Power Drives was able to quickly identify and rebuild the entire hydraulic hose system on this Case tractor. It’s important to not try to take on a project of such magnitude alone; any mistake in hydraulics can be a dangerous one. When you don’t quite know where to start, it’s always best to consult the experts.