International differences and standards of hydraulic quick connector accessories

The flat-face quick-connect design makes connecting and disconnecting hydraulic lines quick and easy without the use of tools, while ensuring leak-free connections without pressure drop or risk to the operator.

However, these advantages only apply if the couplings and couplings are properly secured at the pipe ends: it is clear that the technical advantages of the quick coupling cannot be fully utilized if leaks occur at these connection points.

Therefore, when selecting a quick connector, it is also necessary to evaluate suitable fittings.

Accessories are composed of two elements:

• threaded part, which makes it possible to connect the connector and the pipe;
• Seal the system to ensure no leaks.

In turn, the sealing system can employ one of these three different technologies:

• with a seal;
• With threaded cone and hydraulic belt;
• Interlock between two parts with a specific geometry.

Fittings are divided according to different rules and classifications from country to country: only in the US there are a few standards which also take into account the sealing technology used (such as NPT, for pipe conical joints for hydraulic belts, or ORFS, or for fitting ring seals for seals); in the European Union, even though Germany and the UK have their own specific regulations, ISO dominates in order to provide a more general framework.

In addition to pointing out regional differences in the manufacturing process, these various classifications also provide application information (such as SAE for automotive) mainly by component type.

Common accessory types are:

• NPT, or American Pipe Taper, which uses an insulating tape wrapped around a tapered thread to join the male and female threads using the principle of roundness;
• BSP, or British Standard Pipe, using either constant size threaded sections (BSPP) or variable size threaded sections (BSPT);
• The Society of Automotive Engineers (SAE), according to the type of application in the automotive industry, uses different types of quick connectors.

It is essential to understand the reference standard used by the quick coupling, because to consider the compatibility of the basic connection with the pipe in which the quick coupling is installed, it is necessary to ensure that the diameter of the connection point (as indicated on the technical data sheet) and the thread type are the same. Otherwise, the fittings will not be secure, causing leaks, pressure drops and potential hazards to personnel, or the tubing and quick connectors may not connect at all.

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