Don’t wait until something goes wrong to replace your hydraulic hose assemblies. The hoses and couplings are critical for the transfer of hydraulic fluid from the pump to machine components where they supply the pressure and flow to create the force needed to do the work.
Basics of Hoses and Couplings
Most hoses have three layers: the tube, reinforcement, and the cover. These are assembled in a composite structure that allows them to remain flexible and move so they can route where they need too. This also allows for the control of pressure surges and withstands vibration.
At Force Flex Industrial we build and test our hoses to comply with the highest standards from SAE and EN. The equipment your hose assembly is being installed on will provide guidelines for dimensions, material properties, and minimal performance characteristics.
The tube conveys the fluid and is most commonly made of rubber and plastic.The quality of your tubing is critical because it is exposed to industrial situations that often contain corrosive elements. This can result in permeation by chemical agents and some applications can expose extreme variation in temperature.
Your hose assembly is reinforced with natural and synthetic fibers, wires, and monofilaments. This is what gives the hose the strength required to withstand both internal and external pressure fluctuations.
The cover is often made of rubber, plastic, and sometimes textile fabrics to protect the assembly from environmental conditions, abrasion, weathering, and ozone.
The coupling is either a one or two-piece fabrication and often come pre-atached at the ferrule or compressed together as one part. Two-piece designs are crimped together.
Termination is important for a leak-free connection between the hose and a port or another hose. Force Flex Industrial carries a huge number of different end connections to apply to many industry standards.
Requirements for Design of an Assembly
You have to specify certain aspects of your hose assembly to maximize how long it will serve in a worry free environment.
The most important dimensions are the inside diameter and the overall length. The inside diameter controls the fluid velocity to keep it in spec for the application. The wrong diameter can cause changes that can ruin a piece of equipment real fast and in a hurry. It can also cause power loss, heat generation, and noise.
The overall length has to provide proper routing. An assembly that is too short can put excessive stress on the hose and coupling and result in stretching or bending. A hose that is too long is an accident waiting to happen as it can cause friction or get caught on something.
Hose sizes are usually depicted as -4, -6, -8 etc. This is the inside diameter in 1/16 of inches. For example -4 hose has an inside diameter of 4/16” or ¼”. However it should be noted that 100R5 and 100R14 are exceptions and are sized by outside diameter.
When it is time to replace your assembly you can determine the ID (inside diameter) by checking the label. If you can not read the label or it is missing we can help you determine the ID. Never specify using the OD (outside diameter) because the OD can vary based on construction and manufacturer and is not a guaranteed indications of the ID. Remember to always record the overall length and orientation of the coupling before removing a hose.
Temperature is extremely important in any hydraulic system. When the temperature is out of specification the system will suffer decreased performance and the life of the hoses will severely degrade. Internal heat from system components is transferred to the hose through the fluid. External heat occurs when a hose is routed too close to an engine, exhaust, heat exchanger or other high temperature source. This results in cracks and dried out covers. Cracked hoses should be replaced immediately.
Cold temperatures can cause damage if the hoses is flexing or bending below its temperature rating. In general hoses should not be stored in cold storage and if they are they should be allowed to warm up before they are uncoiled or used to prevent cracking of a new hose.
All hoses have a rating for maximum and minimum temperature. We can provide you with technical specifications for most hose manufacturers. A good rule of thumb is that for every 18 degrees Fahrenheit over a hose’s maximum temperature rating the hose life is reduced by 50%.
We can help you select couplings that can withstand extreme temperatures. This is very important for any equipment that will be used outside. We can provide insulating sleeves over your hose assembly for additional protection.
75% of all hydraulic failures result from contaminated fluid. Small particles that you can not see with the naked eye can reduce your operating efficiency by 20%.
When you’re making replacement hoses it is important to ask yourself how did the original hose fail? Does it show signs of abrasion on the cover or temperature cracks? Is the machine having pressure surges? Answering these questions can allow us to make improvements on the hose assembly instead of simply replicating a flawed design.
Recent developments in hydraulic technology have resulted in components that could far exceed the performance of your existing components. This can result in higher pressure and temperature capability, increased flexibility, and more.
The recent development of hybrid hoses has resulted in thinner tubes and covers thanks to smaller but stronger wire reinforcements and more aggressive braiding. So you get hoses with the same ID but smaller OD. They are often more flexible and up to 15% lighter than earlier hose technologies.
This can also result in lower costs. Another great advantage of these newer technologies is that these compact and flexible hoses are easier to install and route in tight applications, require fewer bent-tube fittings, and have an extended lifespan.