When purchasing hydraulic hoses, you will likely need the corresponding hydraulic hose end fittings or couplings. These components are essential for connecting hoses of different lengths, diameters, and pressure ratings to ensure compatibility with the fluid they carry. Fittings allow you to extend the range of your hydraulic hoses and connect them to various hydraulic pumping and actuation components.
Materials Used for Fittings
Hydraulic hose end fittings are made from different materials depending on the application and desired performance:
- Metal: Metal is the most common material used for fittings due to its strength, durability, and heat resistance. Steel, in particular, is widely chosen for high-pressure applications. For added corrosion resistance, stainless steel is a good option. Brass and aluminum are suitable for low to medium-pressure applications and are chemically resistant, though not as strong as steel. These materials are also more affordable, making them ideal for minimizing the cost of hydraulic assemblies.
- Plastic: Plastic fittings offer excellent corrosion resistance but lack the strength and durability of metal. They are the least expensive option and are typically used in low-pressure applications.
Types of Hydraulic Hose End Fittings
Hydraulic fittings come in various sizes and materials, including plastic, stainless steel, and brass, and are selected based on the application, temperature resistance, and sealing strength required. The two primary types of hydraulic hose end fittings are permanent and reusable.
- Permanent Hydraulic Hose Fittings: These fittings are crimped onto the hydraulic hose and consist of two parts: the stem and the ferrule. The stem is inserted into the inner tubing, while the ferrule surrounds the outer cover. The assembly is crimped to secure the fitting permanently. Permanent fittings can either be a two-piece design or a single component, where the ferrule is integrated with the stem. In some cases, the hose may require skiving, which involves removing part of the outer cover to create a tighter seal.
Image Text: Stainless Reusable Fittings
- Reusable Hydraulic Hose Fittings: Reusable fittings are field-attachable and do not require a crimping tool. These fittings are commonly used in applications where access to a crimping tool is limited, or a less secure seal is sufficient. Instead of a ferrule, reusable fittings use a collar placed on the hose end. The stem is threaded into the collar, creating a seal. These fittings can be disassembled and reused.
Factors to Consider When Selecting Hydraulic Hose Fittings
- Seal Type: Fittings are available in different standards, including NPT/NPTF, JIC, ORB, BSPT, SAE, ISO, DIN, and Metric, among others. For instance, the NPT/NPTF standard, widely used in North America, features tapered threads for a leak-proof seal. When selecting fittings, consider factors such as flare angles, O-ring types, and seat diameters.
- Temperature: The temperature rating of fittings depends on the material and the type of seal used. O-rings, in particular, have a maximum temperature limit. Operating beyond this limit can cause the O-ring to deform, leading to leaks.
- Pressure: Fittings are rated for different pressure levels. Fittings sealed with O-rings generally have higher pressure ratings than those with metal-to-metal seals, provided that the medium and temperature are within the O-ring’s operating limits. Avoid over-torquing fittings, as this can damage threads and cause leaks.
- Media Compatibility: Ensure that the hydraulic medium is compatible with the fittings and O-rings. Incompatible media, such as petroleum or synthetic fluids, can erode O-rings, leading to failure. Always review the technical specifications before installation.
Popular Hydraulic Hose Fittings Manufacturers
Several manufacturers produce high-quality, durable hydraulic hose fittings. Some of the most popular include:
- Parker: A global leader in hydraulic hose end fittings, Parker offers a wide range of products for various hydraulic assemblies.
- Eaton: Eaton is a large conglomerate with subdivisions like Aeroquip and Weatherhead, specializing in hydraulic hose ends for aerospace and general applications.
- Gates: Gates is not only a manufacturer of fluid transfer accessories but also a solutions provider. They offer an extensive catalog of hydraulic hose fittings and complete hose assemblies.
- QC Hydraulics: A leading manufacturer of stainless steel hydraulic hose fittings, tube fittings and adapters in China. Specializing in stainless steel materials. Like SS 304, SS316, SS316Ti.