Connection technology - connection of hydraulic components in hydraulic systems

Hydraulic ball valves are essential components in hydraulic systems and are used for efficient and rapid control of fluid flow. They consist of a body with a rotatable hollow ball that contains a bore. In the open position, the bore is aligned with the flow direction, allowing unrestricted flow. A 90° rotation of the ball positions the bore perpendicular to the flow direction and completely blocks the flow. This design enables quick and secure flow control with just a quarter turn.

Ball valves are very robust and durable, even when operated infrequently, and require only minimal maintenance. They are resistant to clogging and abrasive media and can reduce water hammer when actuated slowly. Hydraulic ball valves are ideal for high-pressure applications up to 500 bar or even 800 bar. They are available in 2-way, 3-way and multi-way versions, with 3-way ball valves being particularly advantageous for complex flow control tasks such as diverting, distributing or mixing fluids in high-pressure systems.

The material selection for hydraulic ball valves is crucial for performance, service life and compatibility with operating conditions. Common materials for the valve body include:

• Stainless steel: Corrosion and heat resistant (up to approx. 400 °C), ideal for high-pressure and aggressive media
• Brass: Cost-effective, corrosion resistant, up to approx. 200 °C, suitable for water and mild chemicals
• Plastic: Lightweight, chemically resistant, used for special low-pressure applications
• Steel and special alloys: Suitable for extremely high pressures up to 2000 bar

Seat seals are typically made from POM, NBR, EPDM, PTFE or FKM, depending on pressure, temperature and medium, to prevent corrosion, material degradation and leakage.

Hydraulic quick couplings allow fast, safe and leak-free connection or disconnection of lines in systems requiring flexible and interchangeable connections. Typical application areas include:

• Agricultural machinery and implements
• Industrial machinery and modular systems
• Construction and off-road equipment
• Mobile hydraulic systems

They reduce downtime, are robust, and are available in materials such as steel, stainless steel or brass/aluminium.

The selection of the correct hydraulic quick coupling depends on:

• Material compatibility with medium and environment
• Operating pressure and the ability to connect under residual pressure
• Connection type, nominal size and thread type according to standard
• Seal type suitable for medium and temperature range
• Standards such as ISO 7241, ISO 16028 for quality and compatibility
• Ease of maintenance and resistance to environmental influences

The main difference lies in flexibility and typical application areas:

• Rigid and non-flexible: Used where lines are installed in fixed and stationary positions, e.g., in stationary machinery or vehicle frames.
• Higher pressure resistance: Can safely handle extremely high pressures (often up to 630 bar and beyond) and are more resistant to external mechanical impacts such as stone chipping.
• Longer service life: When installed and maintained correctly, hydraulic tubes achieve a very long operating lifetime.
• Lower maintenance requirements: Less prone to wear compared to hoses.
• Reduced pressure loss: Smooth internal surfaces and rigid structures minimize flow resistance.

• Flexible and movable: Ideal for dynamic applications where components move (e.g., joints on construction machinery, suspension systems).
• Easier handling and installation: Easier to route and adapt.
• Lower pressure resistance: Although designed for high pressures, hoses are generally less pressure-resistant than tubes and wear out faster.
• Higher maintenance demand: Must be inspected and replaced more frequently due to wear or damage.

Hydraulic hose crimping machines permanently connect hydraulic hoses and fittings by applying force- and form-locking crimping. Advantages include:

• Fast on-site repair and assembly
• Minimized downtime
• Cost efficiency
• Increased safety through standard-compliant crimping
• Adaptation to specific requirements

• Tapered thread fittings (NPT, BSPT)
• Parallel thread fittings (BSPP, metric)
• Cutting ring fittings (DIN 2353)
• Flared fittings (JIC 37°)
• ORFS fittings
• Flange connections (SAE)

The selection depends on pressure requirements, thread standard, material, connection type, size and ease of assembly.

• Determine nominal diameter (DN) by measuring the inside diameter
• Determine thread type and size by measuring outside diameter and pitch
• Match measurements with standard tables (BSP, NPT, metric, SAE)
• Check socket and plug dimensions for quick couplings

By systematically measuring and matching with standards, safe and compatible selection is ensured.