YUKEN BG-03-3231Y、BG-06-3231Y、BG-02-3231Y

YUKEN Low Noise Type Pilot Operated Relief Valves: BG-02, BG-03, BG-06, BG-10
YUKEN BG series low noise type pilot operated relief valves are specially developed to protect hydraulic pumps and control valves from overpressure while maintaining stable pressure in the hydraulic system. With optimized low-noise structural design, they effectively reduce fluid noise during operation, making them suitable for both industrial and engineering hydraulic systems with strict noise requirements. The BG-02, BG-03, BG-06, and BG-10 are four core models in this series, differing mainly in valve size, maximum flow capacity, installation dimensions, and mass to adapt to hydraulic systems of different scales and working conditions. Below is a detailed introduction to their general characteristics, specific specifications, key features, and application scenarios.

1. General Characteristics of BG Series
   All models in the BG series share the same core design concept and functional advantages, ensuring reliable performance and convenient use in various hydraulic systems:

• Low Noise Performance: Optimized valve port and flow channel structure minimizes fluid turbulence, significantly reducing operational noise. Under standard test conditions (return line back pressure 0.1 MPa, viscosity 35 mm²/s, measured 1m from the valve), the noise level is controlled below 70 dB(A), making them ideal for noise-sensitive environments.
• Pilot Operated Structure: Adopts a pilot operated design, which provides precise pressure control and stable performance, even under fluctuating system flow conditions. It can effectively protect the hydraulic system from overpressure damage.
• Sub-plate Mounting: Features sub-plate mounting (indicated by “G” in the series designation), with compact structure, easy installation and maintenance. The mounting surface complies with international ISO standards, ensuring good interchangeability with conventional models.
• Wide Pressure Adjustment Range: The pressure adjustment range is 0.5~25 MPa (72~3630 psi), and different pressure ranges can be selected according to actual system needs, providing flexible adaptation.
• Remote Control Capability: Remote control and unloading can be realized through the vent circuit, which enriches the control mode of the hydraulic system and facilitates system design[superscript:7].
• Durable Construction: The valve body is made of high-strength cast iron, with strong pressure resistance and long service life. The operating temperature range is 0~100℃, adapting to various harsh working environments.

1. Detailed Introduction of Each Model
   2.1 BG-02 Low Noise Type Pilot Operated Relief Valve
   As the smallest model in the series, the BG-02 is designed for small hydraulic systems or auxiliary circuits with limited installation space and low flow requirements. It inherits all the low-noise and high-reliability advantages of the BG series, with a compact structure and light weight.
   Core Specifications

• Maximum Operating Pressure: 25 MPa (3630 psi)
• Maximum Flow Rate: Approx. 16 L/min (4.2 U.S. gpm)
• Pressure Adjustment Range: 0.5~25 MPa (72~3630 psi)
• Valve Size: 02 (nominal diameter suitable for small flow circuits)
• Mounting Type: Sub-plate mounting, compatible with standard sub-plate dimensions
• Approximate Mass: 1.5 kg (3.3 lbs)
• Minimum Flow Requirement: To ensure stable pressure control, the system flow should not be less than 5 L/min
• BG-02-3231Y Specific Parameters: Same as the base model BG-02 (consistent maximum pressure, flow rate and mounting type); the suffix “3231Y” indicates standard pressure adjustment configuration, no additional functional modifications, maintaining low-noise performance and remote control capability.
  Key Features & Applications
  The BG-02 is compact, lightweight, and low-noise, making it suitable for small hydraulic systems, precision hydraulic control circuits, and auxiliary circuits of medium-sized equipment. Typical applications include small-scale construction machinery, precision machine tools, and light-duty hydraulic equipment, where it is responsible for pressure regulation and overpressure protection of auxiliary circuits to ensure stable and quiet operation of the system.
  2.2 BG-03 Low Noise Type Pilot Operated Relief Valve
  The BG-03 is a medium-sized model in the series, with a balanced combination of flow capacity, size, and performance, making it one of the most widely used models in various hydraulic systems. Its mounting surface conforms to ISO 6264-06-09-1-97, ensuring good interchangeability.
  Core Specifications
• Maximum Operating Pressure: 25 MPa (3630 psi)[superscript:5]
• Maximum Flow Rate: 100 L/min (26.4 U.S. gpm)
• Pressure Adjustment Range: 4~25 MPa (580~3630 psi)
• Valve Size: 03 (nominal diameter approx. 3 mm)
• Mounting Type: Sub-plate mounting
• Approximate Mass: 4.1 kg (9.0 lbs)
• Minimum Flow Requirement: 5 L/min (to avoid unstable pressure setting)
• Mounting Surface Dimensions: Conforms to ISO 6264-06-09-1-97
• BG-03-3231Y Specific Parameters: Consistent with the base model BG-03 in core specifications; “3231Y” denotes standard configuration without optional accessories, ensuring stable pressure control and low-noise operation (≤70 dB(A) under standard test conditions), compatible with the same sub-plate models as BG-03.
  Key Features & Applications
  With excellent noise reduction performance and stable pressure control, the BG-03 is suitable for medium-sized hydraulic systems and main circuits of general engineering machinery. It can be equipped with an optional high venting pressure feature to shorten the transition time from unloading to on-loading. Typical applications include construction machinery (such as cranes), metallurgical equipment, plastic machinery, and hydraulic stations, where it plays a key role in pressure regulation and system protection.
  2.3 BG-06 Low Noise Type Pilot Operated Relief Valve
  The BG-06 is a medium-to-large model in the series, designed for hydraulic systems that require medium to high flow and stable pressure regulation. It adopts an optimized flow channel design to ensure stable operation even under high-flow conditions, and its mounting surface conforms to ISO 6264-08-13-1-97.
  Core Specifications
• Maximum Operating Pressure: 25 MPa (3630 psi)
• Maximum Flow Rate: 200 L/min (52.8 U.S. gpm)
• Pressure Adjustment Range: 1.5~25 MPa (220~3630 psi)
• Valve Size: 06 (nominal diameter approx. 6 mm)
• Mounting Type: Sub-plate mounting
• Approximate Mass: 5.0 kg (11.0 lbs)
• Minimum Flow Requirement: 8 L/min (to ensure stable pressure control)
• Mounting Surface Dimensions: Conforms to ISO 6264-08-13-1-97
• BG-06-3231Y Specific Parameters: Core specifications are the same as the base model BG-06; the suffix “3231Y” indicates standard pressure control configuration, no vent restrictor or high venting pressure option, compatible with sub-plate models BGM-06-20 and BGM-06X-20, maintaining high reliability and low-noise performance.
  Key Features & Applications
  The BG-06 has higher flow capacity than the BG-02 and BG-03, with low noise emission and high reliability even under harsh working conditions. It is compatible with sub-plate models BGM-06-20 and BGM-06X-20, with connection calibers of 3/4 and 1 respectively. Typical applications include medium-to-large construction machinery, hydraulic presses, and industrial hydraulic stations, where it is responsible for pressure regulation and overpressure protection of the main hydraulic circuit.
  2.4 BG-10 Low Noise Type Pilot Operated Relief Valve
  As the largest model in the series, the BG-10 is designed for large hydraulic systems or main circuits that require high flow, high pressure, and low noise. It has the largest flow capacity and size among the four models, and its mounting surface conforms to ISO 6264-10-17-1-97.
  Core Specifications
• Maximum Operating Pressure: 25 MPa (3630 psi)[superscript:5]
• Maximum Flow Rate: 400 L/min (105.7 U.S. gpm)
• Pressure Adjustment Range: 1.1~25 MPa (160~3630 psi)
• Valve Size: 10 (nominal diameter approx. 10 mm)
• Mounting Type: Sub-plate mounting
• Approximate Mass: 10.5 kg (23.1 lbs)
• Minimum Flow Requirement: 15 L/min (to avoid unstable pressure setting)
• Mounting Surface Dimensions: Conforms to ISO 6264-10-17-1-97
  Key Features & Applications
  The BG-10 has the strongest flow capacity and load-bearing capacity among the four models, with excellent noise reduction performance and stable pressure control. It is compatible with sub-plate models BGM-10-20 and BGM-10X-20, with connection calibers of 1 1/4 and 1 1/2 respectively. Typical applications include large-tonnage cranes, large hydraulic presses, heavy-duty engineering machinery, and large-scale hydraulic stations, where it plays a crucial role in ensuring the stable and efficient operation of the entire hydraulic system.

1. Installation and Operation Notes

• Mounting: The valve adopts sub-plate mounting; ensure the mounting surface has a good machined finish (surface roughness ≤1.6 μm) to avoid oil leakage. When using a sub-plate, select the corresponding sub-plate model according to the valve size.
• Pressure Adjustment: Loosen the lock nut and rotate the pressure adjustment handle clockwise to increase pressure or counterclockwise to decrease pressure; tighten the lock nut after adjustment to prevent pressure deviation. The adjustment pressure is limited by the installed washer, and one washer is equivalent to approximately 10 MPa.
• Vent Circuit: When using a remote control relief valve in the vent circuit, minimize the pipeline volume to avoid jitter. The tank pipeline should be directly connected to the oil tank and not connected to the tank pipeline of other valves.
• Flow Requirement: Ensure the system flow meets the minimum flow requirement of the valve; otherwise, the set pressure may be unstable.
• Maintenance: Regularly inspect and clean the valve core and valve seat to avoid blockage caused by oil impurities, which may affect pressure control accuracy and noise performance. The product design may be modified without prior notice; refer to the latest product manual for detailed parameters.
• Accessories: The valve is equipped with mounting bolts; select the appropriate bolt size according to the valve model (e.g., M12×40L for BG-03, M16×50L for BG-06, M20×60L for BG-10).