Special Supplying Quick Couplings for Hydraulic and Pneumatic system

How to buy correct quick coupling

For the vast majority of quick coupling purchasers, their typical need is to replace damaged or aging quick couplings on their current equipment. They can identify compatible replacements based on known specifications such as ISO standards, connection types, application environments, functional requirements, material compositions, or thread parameters. Our website’s menu system allows users to navigate through categorized listings and apply detailed filters to locate interchangeable products.

When selecting quick couplings for product design, critical application parameters must guide the decision-making process:

Material Selection Based on Fluid Media

Different fluids require specific coupling materials and seal compounds, with cost considerations playing a significant role. Our material compatibility chart (available for download) assists in proper selection, though direct consultation is recommended for complex applications.

Our production focuses on metallic couplings using:

• Primary materials: Carbon steel, stainless steel, brass
• Specialty options: Aluminum alloys, tool steels
• Seal materials feature specialized elastomers with distinct performance characteristics:
• Common: Nitrile (NBR), Fluorocarbon (FKM)
• Specialized: EPDM, Neoprene (CR)
• Premium: Perfluoroelastomer (FFKM) for extreme conditions

Pressure Rating Considerations

In most hydraulic circuit applications, the choice of working pressure and burst pressure needs to be carefully considered. However, many quick coupling users have a common misconception that products of the same standard have identical design working pressures. While the working pressure can be found in international standards such as ISO 7241, this only represents the minimum requirement set by the standard. In reality, due to differences in design among manufacturers, the actual working pressure can vary. Typically, a manufacturer’s specified working pressure is higher than the standard requirement.

For safety considerations, manufacturers typically set the working pressure at about 1/4 to 1/3 of the burst pressure and conduct 10,000 cycles of pressure testing to verify it. In practice, the actual working pressure can be increased by 10%-15% above the rated value. As a result, many genuine manufacturers specify a working pressure that exceeds the minimum requirement set by ISO standards. Operating at a slightly higher pressure does not compromise the service life of the quick coupling.

Additionally, working pressure varies depending on the application and testing conditions. Some applications, such as agricultural machinery, involve frequent pressure fluctuations, whereas others, like hydraulic jacks, have a more stable pressure output. Because of these differences, the pressure testing methods for these applications differ, leading to significant variations in the rated working pressure even for couplings made from the same material (e.g., carbon steel).

However, if the operating environment changes, a quick coupling originally rated for a higher working pressure may no longer meet the requirements in a different application. For example, a quick coupling rated for 720 bar in a hydraulic jack application may only be suitable for 350-400 bar in agricultural and forestry machinery. Therefore, when selecting a quick coupling, users should not rely solely on the working pressure rating. It is essential to consult the manufacturer to ensure compatibility with the intended application.