Hydraulic hoses are the lifelines of hydraulic systems, critical for transmitting fluid and energy across a wide range of industries. These include oil and gas, mining, construction, agriculture, manufacturing, railroads, automotive, food production, and pharmaceuticals, among others. They provide flexible connections between two fluid ports, enabling hydraulic systems to function effectively under extreme conditions, such as high temperatures, high pressures, and even vacuums.
Typically, hydraulic hoses are constructed from reinforced rubber or thermoplastic materials, which are wrapped with flexible metal or fiber reinforcements, then covered with a protective layer. Some hoses are made from Teflon® and reinforced with stainless steel braids for added strength and durability. The reinforcement, either braided or spiral-wrapped, ensures the hose maintains flexibility while withstanding high levels of stress.
In simple terms, a hydraulic system consists of key components: a reservoir, pump, cylinder, and hose. Hydraulic hoses play a crucial role by transporting pressurized hydraulic fluid, which drives the mechanical system by transferring energy from the pump to the cylinder or motor.
For example, the pump draws fluid from the reservoir, pressurizes it, and sends it through a multi-wire hose to the cylinder. As the cylinder's piston retracts, the fluid is pushed back through the return hose into the reservoir, where it is cooled and prepared for the next cycle.
Selecting the right hydraulic hose is as important as choosing any other system component, such as fittings. To simplify this process, the acronym STAMPED—which stands for Size, Temperature, Application, Media/Material, Pressure, Ends, and Delivery—is commonly used as a guideline.
Hydraulic hoses are available in various materials and constructions to meet specific application needs. Manufacturers must adhere to stringent standards, such as the 19 SAE 100R specifications and numerous European EN standards. While the exact requirements depend on the application, most hoses fall into one of three main categories:
By understanding these options and specifications, you can select the most suitable hydraulic hose to ensure reliable performance and longevity in your hydraulic system.
Once you understand your requirements, the rest of the process becomes much simpler. However, it’s crucial to keep three key points in mind:
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Hydraulic hose part numbers reflect the inside diameter in 16ths of an inch.
For instance, a "-6" indicates a 3/8-inch inside diameter, "-8" represents a 1/2-inch inside diameter, "-10" corresponds to 5/8-inch, and "-16" refers to a 1-inch inside diameter. Taking -6 as an example, the part number H28006 identifies a hose in the H280 series, with a size -6 (or 3/8-inch inside diameter). The H280 series is a two-wire braided hydraulic hose widely used across the hydraulic industry. -
Most hydraulic hoses have a 4:1 safety factor.
This means a hose rated for 3,000 PSI must have a burst pressure of at least 12,000 PSI, ensuring a high margin of safety during operation. -
Hydraulic hoses are designed with multiple layers for strength and durability.
Inside the hose, a reinforced rubber or thermoplastic conduit carries the hydraulic fluid. Surrounding this, a flexible metal or fiber wire wrap provides the strength needed to withstand high pressures. The outer covering protects the reinforcement layer from corrosion, abrasion, and other environmental factors.
Three Layers of a Hose Structure
While there are many types and uses for rubber hoses, all hoses have one basic function: to transport liquids or gases. In terms of the construction of rubber hoses, most hoses are made up of three layers.
The first layer is the innermost "tube", which is formed when rubber is forced through a profile to a specific size, and it serves two purposes: to contain the liquid being transported and to resist being broken down by the liquid.
The second layer is a reinforcement layer, called reinforcement. If the pressure of the contained fluid suddenly increases, the pipe may require a fabric or wire carcass reinforcement. This ensures that the pipe is protected from internal pressure and external forces. Carcass reinforcement wire is applied by braiding, knitting, spiraling, winding or weaving.
The third and outermost layer is the "cover". The cover provides additional protection for the hose from external damage and environmental degradation, such as ozone. The cover can be color coded to aid identification or improve aesthetics. While reinforcement and cover layers are commonly used, "homogeneous" hoses with no added layers are also available.
The tube protects the reinforcement from internal forces, while the cover's primary function is to protect the reinforcement from external forces. Liners and covers are made from various types of rubber, including natural rubber, styrene-butadiene rubber (SBR), nitrile rubber, butyl rubber, and EPDM. Typical reinforcement materials include cotton rayon, polyester, nylon, aramid fiber, and steel wire.
3 Hose Options
As mentioned above, there are three main choices for hose material and construction on the pressure side of the hydraulic system and one on the return side in most applications.
1. Nitrile
Nitrile hydraulic hoses are the most common as they are compatible with most hydraulic fluids. They are either made with a textile braid for low pressure applications under 1,000 PSI or a high tensile strength steel wire braid for pressures up to or over 7,000 PSI. Steel wire reinforcement is the most common and the number of braid layers can range from one to six.
1-Wire Braid – Less common than 2-Wire hoses. Used in low pressure hydraulic systems.
2-Wire Braid – Widely used due to its affordable price and wide range of medium pressure applications.
4-Wire Braid – Commonly used in heavy equipment, it can handle high pressures from 4,000 to 6,000 PSI and is suitable for handling frequent pressure pulses.
6-Wire Braid - Typically used for large diameter hoses that require ultra-high pressures up to 7,000 PSI.
Some manufacturers make hoses with extra durable covers for applications that require protection from severe impact and abrasion. These hose covers are typically Ultra High Molecular Weight Polyethylene (UHMW), a very tough plastic that is highly resistant to abrasion and wear. Polyethylene is a popular plastic for many industrial applications that require good chemical resistance, high durability, and a low coefficient of friction.
2. Thermoplastics
Thermoplastic Polyurethane (TPU) is a type of thermoplastic polyurethane used to make hydraulic hoses. It is typically constructed of a nylon tube, synthetic fiber reinforcement, and a polyurethane cover. Due to its low electrical conductivity, it is often used in common hydraulic applications such as basic material handling equipment and near electrical systems, such as bucket lifts for servicing electrical wires. It is often used in applications where steel wire reinforcement is not appropriate and can withstand pressures similar to 1 and 2 braided steel wire hoses. The polyurethane cover is resistant to abrasion and is often used near forklift chain rollers.
Thermoplastic hydraulic hose has the durability and strength of plastic with the flexibility of rubber. It is an extremely versatile material that can withstand temperatures up to 275°F (135°C). They are often used in high-pressure hydraulic systems, chemical gas handling, and other applications that require pressurized gas delivery.
3. Teflon/PTFE
PTFE is a generic formulation of DuPont Teflon material. PTFE hydraulic hose consists of Teflon tube and stainless steel braid reinforcement and does not require an outer layer because the stainless steel braid does not corrode in most cases. Teflon hose is used for chemical compatibility, corrosion resistance, and high temperature applications up to 450°F (232°C).
When specifying Teflon hose, size and bend radius should be considered. Sizes are generally 1/16 inch smaller than the part number shown. For example, a -6 is 3/8 inch for other hose materials, but a -6 is 5/16 inch for Teflon.
Also, the bend radius is not as small as with other hose materials. Teflon hose is a hard plastic - if you bend it to the point of kinking, there is a weak section and the hose will fail.
Hydraulic Return Hose
The return hose is used to handle suction and return hydraulic fluid back to the system. The hydraulic return hose is usually a rubber hose with a textile braid that creates positive pressure through the spiral wire to create suction.
Rubber Hose Manufacturing
In terms of manufacturing, rubber hoses are produced in a variety of ways, including extrusion, spiral wrapping, calendaring, hand layup, and molding. Generally speaking, small diameter hoses are primarily produced by extrusion, while large diameter hoses are often produced by spiral wrapping.
Rubber Hose Industry
Now that we understand the structure of rubber hoses, let's explore the rubber hose segment of the industrial rubber products industry, which includes vehicle, fluid power, water, air, and other industrial types.
Vehicle hoses are and will continue to be the largest market segment, accounting for more than one-third of total hose demand. Rising vehicle production and an increase in the total number of vehicles in use are driving demand in the OEM and replacement markets, respectively. High-value custom hoses designed for under-the-hood applications in harsh environments also support demand.
Rubber Hose Market
Rubber hoses are used in a wide range of durable goods, including industrial machinery, motor vehicles, aerospace equipment, and other transportation equipment. Nearly two-thirds of total rubber hose demand comes from industrial equipment, including off-road equipment such as construction and agricultural equipment. Almost all categories of hoses are used in industrial equipment, with fluid power, industrial, and vehicle hoses being particularly prevalent. The automotive industry is also a large consumer of rubber hoses for engine, transmission, steering, air conditioning and brake systems.
Applications of Rubber Hoses
Now that we know about rubber hoses, manufacturing, the industry, and the market and demand, let’s now turn our attention to the applications of rubber hoses. Since rubber hoses are flexible and can absorb vibrations, they are suitable for designs that move and shake. High-pressure hydraulic applications often use hoses to contain water-oil and water-glycol mixtures as well as low-viscosity mineral oils.
Step-By-Step Hydraulic Hose Fabrication
Step 1: Gather Tools and Materials
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Hydraulic hose
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Hydraulic hose fitting
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Hose lubricant
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Calipers
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Paint pen
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Safety goggles
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Crimping machine
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Crimping die and collar
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Ultra Clean nozzle, projectiles, and seal caps
Step 2: Wear Safety Equipment
Always wear safety goggles while cutting and crimping to comply with company safety protocols.
Step 3: Measure and Cut the Hose
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Measure the required hose length and cut it using a hose saw. Consider the cutoff factor for critical lengths.
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Ensure a clean edge after cutting; use a file if necessary.
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Clean the hose ends to minimize contamination. Fire Ultra Clean projectiles through the hose from both ends to remove debris and ensure cleanliness.
Step 4: Select Fitting Series
Choose the appropriate fitting series based on:
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Working pressure
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Style and type
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Orientation
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Attachment methods
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Corrosion-resistant material
Important: Do not mix hose and fitting brands.
Step 5: Mark Insertion Depth and Attach Fittings
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Use a depth block to mark the insertion depth on the hose with a paint pen.
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Lubricate the hose with P-80 if needed, avoiding lubrication for spiral hoses.
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Push the hose into the fitting until the mark aligns with the fitting shell's edge.
Step 6: Verify Crimper Settings
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Confirm the crimping machine's capabilities.
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Adjust the settings or replace the die as needed to match the hose specifications.
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Use Parker Crimpsource or similar references for technical specifications.
Step 7: Select the Crimping Die
Choose the correct die set based on the crimper decal and hose type. Lubricate the die bowl with lithium-based grease if needed.
Step 8: Position the Hose in the Crimper
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Insert the hose into the crimping machine (bottom-loading) until the fitting is visible above the die.
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Ensure the top of the fitting is aligned properly, with the fitting resting on the die step.
Step 9: Install the Die Ring
Place the die ring on the adapter bowl as instructed by the crimper decal.
Step 10: Crimp the Hose
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Turn on the machine and let the cylinder head move down.
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Allow the collar to compress the die fully. Avoid touching the machine until the process completes.
Step 11: Verify Crimp Diameter
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Check the hose for movement by inspecting the paint mark. If it’s misaligned, the crimp is invalid.
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Measure the crimp diameter on the fitting and compare it to the decal reference. Ensure the crimp matches specifications.
Step 12: Cap the Hose Assembly
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Clean the hose ends and cap both ends with plastic or heat-shrink caps.
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Use UltraClean heat shrink caps for a contamination-free seal. These are available in various sizes and quantities to meet your needs.
As you can see, the world of rubber hoses is amazing. And this is just the tip of the rubber and plastic iceberg. Whether it’s rapid manufacturing of plastic injection molded parts or fast-turnaround rubber parts, well-known brands choose us not only to buy our parts, but also to work with us.