PRL500 PRL400 Bieri Solenoid Relief Valve 500Bar

Product Overview

The PRL/PIL 400 and 500 Series (including models like PRL400, PRL500, PIL400, PIL500, and specific configurations such as PRL400PC06P30 and PRL500PC10P40) are pilot-operated proportional relief and solenoid valves engineered for ultra-high-pressure hydraulic systems. Widely used to replace premium European high-pressure valves like Bieri, this series strictly complies with ISO 4401 mounting standards, offering 100% drop-in mechanical and hydraulic interchangeability. Forged from ultra-high-strength alloy steel and utilizing micron-level precision lapping, these valves maintain exceptional pressure control accuracy and near-zero internal leakage even under extreme operating pressures up to 500 bar. Every valve undergoes rigorous 100% factory bench testing under 500 bar simulated load conditions to ensure perfect electro-hydraulic dynamic response, guaranteeing a seamless and highly reliable replacement for your critical high-pressure applications.

Technical Specifications 

• Full Model Code: PRL500 / PRL400 / PIL500 / PIL400 (Typical codes: PRL400PC06P30, PRL500PC10P40)

• Nominal Size: PC06 (NG06 / CETOP 3) / PC10 (NG10 / CETOP 5)

• Max Operating Pressure: 400 bar (PRL400 series) / 500 bar (PRL500 series)

• Pressure Setting Ranges: P30 (Up to 300 bar) / P40 (Up to 400 bar), multiple stages available

• Max Flow Capacity: 25 L/min (NG06) / 60 L/min (NG10)

• Control Method: Solenoid pilot / Proportional control (24V DC / 12V DC options)

• Internal Leakage: Ultra-low internal bypass design (High-pressure leak-tight standard)

• Fluid & Operating Temp: Mineral oil, -20°C to +80°C

• Net Weight: Approx. 1.8 kg (NG06) / 2.9 kg (NG10)

Key Technical Advantages

• Ultra-High Pressure Capability & 100% Drop-In Fit: Designed for 400-500 bar extremes, the subplate mounting patterns strictly match OEM ISO 4401 specifications, allowing for immediate plug-and-play installation without manifold modifications.

• Hardened Spool & Erosion Resistance: The main spool and sleeve are constructed from specialized alloy steel and induction-hardened, preventing cavitation erosion and eliminating sticking under high-frequency actuations.

• High-Precision Proportional Pilot Control: The optimized pilot stage paired with a high-performance solenoid ensures high-resolution pressure adjustments, minimal hysteresis, and a smooth, linear pressure rise.

• 100% Extreme Load Bench Tested: Every unit is subjected to automated 500 bar pressure holding tests, step response verification, and full-range relief curve profiling prior to dispatch to ensure zero-defect reliability.

Application Areas

• High-Pressure Hydraulic Tools & Rescue: Hydraulic shears, spreaders, and micro high-pressure power units (HPUs).

• Testing Rigs & Laboratory Equipment: Aerospace material tensile testers and ultra-high-pressure burst test benches.

• Heavy Machine Tools & Clamping: High-pressure zero-point clamping systems, press holding circuits, and hydrostatic bearing supplies.

• Offshore & Metallurgical Equipment: Subsea ROV hydraulic systems and high-pressure servo controls for rolling mills.

Expert Maintenance Tips

• Mandatory System Bleeding: After installing the PRL/PIL valve, actuate the solenoid repeatedly at low pressure (under 50 bar) and open the highest bleed port in the system until all air is expelled. Trapped air at 500 bar will cause severe cavitation, vibration, and noise.

• Maintain Strict Fluid Cleanliness: Ultra-high-pressure proportional valves are highly sensitive to contamination. Maintain oil cleanliness strictly to ISO 4406 16/14/11 (NAS Class 5) and install a high-pressure micron-rated filter upstream of the P port.

• Bolt Grade & Torque Specs: Operating at 500 bar requires Grade 12.9 high-tensile mounting bolts. For NG06 sizes, torque the bolts diagonally to exactly 15 N·m to ensure O-rings are securely compressed and not extruded under extreme pressure.