YOULI SN-3/8S-3/28L/28L/28L/18L/18L/18L Multiple Control Hydraulic Valve

The YOULI SN-3/8S-3/28L/28L/28L/18L/18L/18L Multiple Control Hydraulic Valve is a sophisticated, sectional directional control valve engineered for robust performance in demanding industrial applications. This valve offers exceptional versatility with its multi-function capabilities, compact construction, and low-pressure drop, ensuring high efficiency and a prolonged service life. It supports various control types, including manual, pneumatic, and electro-hydraulic actuation, making it adaptable to a wide range of system requirements. The SN-3 series is designed for sub-plate mounting and features high-accuracy, hardened spools for sustained precision. Key technical parameters include a nominal flow rate of 50 L/min (13 US gpm), with maximum operating pressures of 315 bar (4600 psi) for parallel or tandem circuits and 250 bar (3050 psi) for series circuits. The fluid temperature range is from -20°C to 80°C with NBR seals and -20°C to 100°C with FPM seals.

Product Specifications

| Parameter             | Value                                               |

| :-------------------- | :-------------------------------------------------- |

| Model Series          | SN-3                                                |

| Nominal Flow Rate     | 50 L/min (13 US gpm)                                |

| Max. Operating Pressure (Parallel/Tandem) | 315 bar (4600 psi)                                  |

| Max. Operating Pressure (Series) | 250 bar (3050 psi)                                  |

| Max. Back Pressure (Outlet Port T) | 25 bar (360 psi)                                    |

| Fluid Temperature (NBR Seals) | -20°C to 80°C (-4°F to 176°F)                        |

| Fluid Temperature (FPM Seals) | -20°C to 100°C (-4°F to 212°F)                       |

| Operating Viscosity   | 15-75 mm²/s (15-75 cst)                             |

| Minimum Viscosity     | 12 mm²/s (12 cst)                                   |

| Maximum Viscosity     | 400 mm²/s (400 cst)                                 |

| Ambient Temperature Range | -40°C to 60°C (-40°F to 140°F)                       |

| Mounting Type         | Sub-plate                                           |

| Spool Material        | Hardened, high-accuracy steel                       |

| Auxiliary Valves      | Overload, anti-cavitation, combined valves (optional) |

| Circuit Types         | Parallel, series-parallel                           |

Core Features & Market Positioning

The YOULI SN-3/8S-3/28L/28L/28L/18L/18L/18L valve distinguishes itself through its robust construction and high degree of configurability, positioning it as a premium component in the mobile and industrial hydraulics sector. Its sectional design allows for custom assembly, precisely matching specific application needs and avoiding the inefficiencies of oversized or undersized generic valves. This modularity, combined with features like a "C port (oil bridge)" for hydraulic source distribution to other components, underscores its intelligent design for complex hydraulic systems. The valve's low pressure drop and high efficiency translate directly into reduced energy consumption and heat generation, offering a tangible operational cost advantage. Furthermore, YOULI's long-standing expertise in hydraulic valve manufacturing since 1975 ensures a product built on decades of refinement and quality control.

Key Application Scenarios

This versatile hydraulic control valve finds extensive application across numerous industries, particularly where precise and reliable directional control is paramount. It is widely adopted in construction machinery, such as excavators, loaders, and dozers, where multi-functionality is required for boom, stick, and bucket actuation. Agricultural machinery, including tractors and implements, benefits from its precise control for hydraulic implements. Furthermore, the SN-3 series is instrumental in sanitation vehicles, dump trucks, drilling rigs, and various special-purpose vehicles that rely on hydraulic power for their core operations. Its adaptability to different control methods also makes it suitable for specialized industrial automation and material handling equipment.

Practical System Integration Guidance

Integrating the YOULI SN-3/8S-3/28L/28L/28L/18L/18L/18L valve into existing hydraulic systems requires attention to manifold mounting and port connections. The valve is designed for sub-plate mounting, necessitating a compatible manifold block with appropriate porting for pressure, tank, and work ports (A and B). When configuring the valve, engineers must carefully select the number and type of working sections (e.g., 18L for the first section, 28L for subsequent sections) and specify inlet/outlet options, including the presence of a main pressure relief valve on the inlet cover. The control type (manual, pneumatic, electro-hydraulic) and spool function (e.g., A, O, Y, P) must align with the system's operational logic and actuator requirements. Ensuring proper fluid viscosity and temperature management within the specified ranges for the chosen seal material (NBR or FPM) is critical for optimal performance and longevity.

Operation and Risk Mitigation

Safe and efficient operation of the YOULI SN-3/8S-3/28L/28L/28L/18L/18L/18L valve hinges on adherence to system parameters and regular maintenance. It is crucial to operate within the specified maximum pressure and flow rate limits to prevent component damage and system failure. Contamination is a primary cause of hydraulic system failure, making the use of appropriate filtration and regular fluid analysis essential for preventing spool wear, seal degradation, and internal leakage. While specific fault codes are not detailed for this model, common troubleshooting in hydraulic systems often involves checking for spool sticking due to debris, air ingress causing erratic operation, or low pressure due to relief valve issues or pump wear. Visual inspection for external leaks and monitoring system temperature are fundamental practices for early detection of potential problems.

Scalability & Long-Term Value

The inherent modularity of the YOULI SN-3/8S-3/28L/28L/28L/18L/18L/18L valve offers significant scalability for evolving hydraulic system needs. As requirements change, additional working sections can be incorporated into the existing valve assembly, allowing for the control of more actuators or functions without replacing the entire valve manifold. This sectional design simplifies upgrades and modifications, enhancing the long-term value proposition. While direct integration with IIoT platforms would typically be managed through compatible electro-hydraulic or electro-pneumatic control interfaces, the valve's reliable and precise operation provides a stable foundation for modernizing hydraulic systems. Its durable construction and the availability of replacement parts contribute to its longevity and support for smart manufacturing initiatives.

Frequently Asked Questions

Q1: What is the maximum operating pressure for the YOULI SN-3 valve?

The YOULI SN-3 hydraulic valve supports different maximum operating pressures based on circuit configuration. For parallel or tandem circuits, it can handle up to 315 bar (4600 psi).

For series circuits, the maximum operating pressure is rated at 250 bar (3050 psi). It's crucial to adhere to these specifications to ensure safe and effective system operation.

Q2: Can I use different types of control for the YOULI SN-3 valve?

Yes, the YOULI SN-3 valve is highly versatile regarding control methods. It supports manual, pneumatic, and electro-hydraulic actuation.

This allows for integration into systems with varying levels of automation and operator input preferences. The specific model variations will dictate the available control interfaces.

Q3: What are the typical applications for the YOULI SN-3/8S-3/28L/28L/28L/18L/18L/18L valve?

This valve is commonly found in demanding mobile and industrial hydraulic applications. Its robust design makes it ideal for construction machinery and agricultural equipment.

It is also frequently specified for use in sanitation vehicles, dump trucks, and specialized industrial machinery where reliable directional control is critical.

Q4: How does the sectional design of the SN-3 valve benefit system integration?

The sectional design offers significant flexibility for system integration and customization. It allows for specific configurations by adding or arranging working sections as needed.

This modularity ensures that the valve precisely matches the application's hydraulic circuit requirements, leading to improved efficiency and performance.

Q5: What is the recommended fluid viscosity range for this valve?

The YOULI SN-3 valve operates optimally within a specific viscosity range. The recommended operating range is 15-75 mm²/s (15-75 cst).

It is important to maintain viscosity within this range, with a minimum of 12 cst and a maximum of 400 cst, to ensure proper lubrication and sealing.

Q6: What types of auxiliary valves can be incorporated with the SN-3 series?

The SN-3 series supports the integration of various auxiliary valves to enhance system functionality. These can include overload valves, anti-cavitation valves, and other combined valve options.

These auxiliary valves provide critical protection and fine-tuning capabilities for the hydraulic circuit.

Q7: What is the nominal flow rate for the SN-3 sectional directional control valve?

The nominal flow rate for the YOULI SN-3 sectional directional control valve is specified at 50 liters per minute.

This corresponds to approximately 13 US gallons per minute, indicating its capacity for medium-flow hydraulic systems.

Q8: What is the maximum back pressure allowed on the outlet port T?

The maximum permissible back pressure on the outlet port T for the YOULI SN-3 valve is 25 bar.

Maintaining back pressure below this limit is essential to prevent overloading of the valve and ensure proper return flow to the tank.

Q9: What is the service temperature range for the seals in the SN-3 valve?

The service temperature range depends on the seal material used. With NBR seals, the range is -20°C to 80°C.

For applications requiring higher temperature resistance, FPM seals offer an extended range of -20°C to 100°C.

Q10: Where can I find more detailed specifications or order information for the YOULI SN-3 valve?

Detailed specifications, ordering codes, and configuration options for the YOULI SN-3 valve are available through official YOULI documentation and authorized distributors.

These resources provide comprehensive guides on selecting and assembling the correct valve configuration for specific industrial requirements.