Yuken EFBG Series Proportional Valve | EFBG-03 EFBG-06 EFBG-10 Flow & Relief Valve

The EFBG Series pilot-operated electro-hydraulic proportional flow and relief valves manufactured by Chengyuan Hydraulic are high-efficiency, multi-functional compound valves fully compatible with Yuken industrial standards. This series integrates a proportional throttle valve and a proportional relief valve into a single, compact block, functioning as an energy-saving fluid power controller. For core configurations such as EFBG-03-250-C-50 and the heavy-flow EFBG-06 and EFBG-10 series, the valve automatically bypasses excess pump flow directly to the reservoir at the current load pressure, drastically cutting thermal energy loss. Every EFBG valve undergoes 100% simulated load testing for flow-pressure hysteresis curves and input current linearity before delivery, guaranteeing that response parameters align with OEM performance for 100% original-place interchangeability.

Technical Specifications:

• Product Series: Yuken EFBG Electro-Hydraulic Proportional Flow & Relief Modulation Valve

• Frame Sizes Available: EFBG-03 (NG10 / CETOP 05) / EFBG-06 (NG20 / CETOP 08) / EFBG-10 (NG32 / CETOP 10)

• Model Designations Support: EFBG-03-250-C-50 / EFBG-06-250-C-50 / EFBG-10-250-H-50

• Maximum Rated Operating Pressure: 250 bar (25 MPa / 3625 psi)

• Maximum Controlled Flow Capacity:

  • EFBG-03 Frame: 125 L/min (33 USgpm)

  • EFBG-06 Frame: 250 L/min (66 USgpm)

  • EFBG-10 Frame: 500 L/min (132 USgpm)

• Pressure Adjustment Range Codes:

  • C-Range: 10 – 160 bar (1.0 – 16 MPa)

  • H-Range: 12 – 250 bar (1.2 – 25 MPa)

• Rated Command Current: 800 mA for flow coil / 800 mA for pressure coil (Standard proportional solenoids)

• Solenoid DC Resistance: ~10 $\Omega$ (at ambient fluid temperature of $20^\circ\text{C}$)

• Hysteresis & Repeatability Bounds: Hysteresis $\le 2\%$, Repeatability $\le 1\%$ (when paired with matched power amplifiers)

Key Technical Advantages:

• Dual Proportional Solenoid Integration Architecture: The EFBG housing mounts two independent high-response proportional solenoids alongside each other, concurrently commanding spool travel (flow) and pilot-stage limiting thresholds (pressure). Operators can continuously modulate actuator velocity and mechanical force over analog signals or PLC control loops.

• Highly Efficient Load-Sensing Unloading Profiling: Functioning as a bypass proportional throttle, the main spool structure incorporates automatic pressure-differential compensation. When the system calls for micro-metering low flow, the valve manages the bypass relief so the primary pump pressure stays just marginally above the actual load demand, slashing system heat generation by over 30%.

• Erosion-Resistant Hardened Spool & Sleeve Sub-assemblies: The core main spool and the proportional pilot poppet are machined from premium tool steel alloys, vacuum heat-treated to HRC 60+ and finish-ground with nano-level tolerances. This structural hardness neutralizes mechanical wear and drifting control metrics under high-cycle fluid erosion.

• Integrated Anti-Vibration Internal Dampening: For the high-capacity profiles (EFBG-06/10), high-damping micro-orifices are embedded inside the internal pilot circuit. This design filters hydraulic pulsations stemming from piston pumps, ensuring smooth, highly linear transitions during 250 bar flow shifting and avoiding pipeline resonance.

Application Areas:

• Heavy Industrial Injection Molding Machines: Delivering multi-stage proportional speed profiling during plastic injection alongside precision pressure reduction in the holding phase.

• Metal Hydroforming Machinery & Heavy Presses: Governing main ram approach velocity curves while providing precise, dynamic pressure scheduling through the compression cycle.

• Primary Metallurgy & Steel Continuous Casting Mills: Driving heavy ladles and coil-hoist platforms with continuous, shock-free acceleration and deceleration dampening.

Expert Maintenance Tips:

• Isolate Pilot Case Drain (Y-Port) Directly to Reservoir: The external pilot drain port (Y-port) on the proportional solenoid tier must be piped completely independently back to the reservoir without backpressure, and the pipe end must terminate below the oil level. Combining this line with a pressurized return manifold will destabilize the pilot poppet balance, resulting in aggressive pressure spikes.

• Strict Amplifier Current Matching Constraints: Actuating the EFBG series requires a dedicated dual-channel proportional power driver card (e.g., AMN-D series). Because flow and pressure coils are fine-tuned for precise impedance, verify that the amplifier’s maximum output current does not exceed 800 mA before powering up to prevent coil burnouts.

• Fluid Filtration & Solenoid Air Bleeding Protocol: Proportional pilot components are vulnerable to particulate contamination; maintain system filtration thresholds to at least ISO 4406 17/14/11 (NAS Class 7). Upon initial priming, manually crack open the air-bleed screws on the ends of the proportional solenoids, purge trapped air bubbles completely, and re-tighten to eliminate control lag or high-frequency chattering.