Hydraulic hoses power some of the world’s hardest-working equipment. They must endure internal and external factors such as environmental conditions, fluid compatibility, working and spike pressures, routing requirements, etc.

An essential component of any hydraulic hose is the inner tube. It must be flexible enough to enable the free passage of hydraulic fluid and strong enough to handle the maximum pressure rating.

Inner Tube

Inner tubes are a necessary component of any bicycle. They hold air pressure, cushion the ride and protect you from punctures. A quality tube should last a long time, though deterioration can occur. Look for a sagged area, a mushroomed bottom end cap, a broken valve stem, or a rubber string between the valve and the rim.

A good tube will also be relatively light. Thinner tubes have less rolling resistance and are more delicate but may not hold air. Latex tubes are a little lighter than butyl but leak air efficiently and require careful fitting.

Butyl tubes have a longer life than latex, but their production is far from “clean.” Fugitive emissions and solid waste result from the mixing, milling, and grinding of crude oil-based products, and volatile organic hazardous air pollutants (VOHAPs) are released in the production of butyl. Both butyl and latex can be recycled into new tubes and tires.

Reinforcement Layer

A hydraulic hose’s middle layer offers the strength to handle extreme pressure. This layer protects the inner tube from abrasion, chemicals, and weather. It can comprise various materials, such as steel wire braid or a helix.

It can also be made from durable synthetic rubber, offering abrasion resistance and flexibility. It determines the working pressure rating of a hose and helps it resist kinking, too.

Depending on the application, the hose’s outer covering can protect it from contaminants, severe weather conditions, and sharp objects. It can also be designed to resist oil, abrasion, and heat. To maximize a hose’s life, it should be routed parallel to machine contours whenever possible. Doing so prevents hard-angle, flow-restricting bends that can injure the reinforcement layer. 

Outer Layer

Unless you work in an area that requires them, you probably need to learn more about what a hydraulic hose accomplishes. However, they play a significant part in many of our daily activities.

The three essential parts of a hydraulic hose include an inner tube, a reinforcing layer, and a protective outer layer. The inner tube is designed to be compatible with the fluid it carries, allowing both free-flowing elasticity and pressure-resistant stress bearing. It is often made from synthetic rubbers, thermoplastics, and PTFE (Teflon).

Reinforcement layers are typically sheath braided, spiral wound wire, or textile-based yarn. The protective outer layer is weather or abrasion resistant, depending on the environment the hose will be used in.

Hydraulic hoses operate at high/very pressures and are rated for maximum and minimum operating temperatures. Exceeding these limits will reduce a hose’s working life and potentially result in premature failure.

Couplings

Couplings – or hydraulic fittings – create a firm seal and connect the hose to other system parts. The type and size of coupling will have a significant impact on your system’s performance. A good expert or manufacturer should help you choose the right one for your application and environment.

Some examples of hydraulic hose couplings are o-ring adaptors, mated angles, and threaded. The o-ring adaptors feature an internal rubber guard that creates a vacuum seal when tightened. They are available in permanent (wrench-sealed) and detachable versions.

Mated angle couplings have straight, parallel threads that mechanically bring two mating angle seats together. They are an excellent choice for high-pressure applications. Threaded couplings are a common choice for low-pressure and medium-pressure systems.