Product Overview
The PBDB-LWN, PPDB-LWN, PBDB-LBN, PPDB-LBN, PBDB-LAN, and PBFB-LAN are pilot-operated pressure control cartridge valves from Sun Hydraulics. Since its founding in 1970, Sun Hydraulics has been a global leader in the design and manufacture of high-performance hydraulic threaded cartridge valves and integrated valve manifolds.
PBDB Series — Pilot-Operated, 2-Way Pressure Reducing Valve:
PBDB-LWN, PBDB-LBN, and PBDB-LAN are Sun Hydraulics PBDB series pilot-operated pressure reducing valves. These valves reduce a high primary pressure at the inlet (port 2) to a constant reduced pressure at port 1, allowing circuits with multiple pressure requirements to be operated using a single pump. Pressure adjustment ranges vary by model suffix:
PBDB-LWN: 10.5–315 bar
PBDB-LBN: 3.5–105 bar
PBDB-LAN: 3.5–210 bar
PPDB Series — Pilot-Operated, 3-Way Reducing/Relieving Valve:
PPDB-LWN and PPDB-LBN are Sun Hydraulics PPDB series pilot-operated pressure reducing/relieving valves. These valves reduce a high primary pressure at the inlet (port 2) to a constant reduced pressure at port 1, while also providing full-flow relief from port 1 to tank (port 3). Compared to the PBDB series, PPDB adds an integrated relief function that provides additional system safety protection.
PBFB Series — High-Flow Pilot-Operated Pressure Reducing Valve:
PBFB-LAN is a Sun Hydraulics PBFB series high-flow pilot-operated pressure reducing valve with 80 L/min capacity and larger T-2A cavity. Functionally identical to the PBDB series—reducing high primary pressure at port 2 to a constant reduced pressure at port 1.
All models feature Sun Hydraulics‘ signature floating style construction, minimizing the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge machining variations.
As original Sun Hydraulics threaded cartridge valves, these products offer complete interchangeability within the same series and cavity, requiring no modifications to manifold designs.
Technical Specifications
PBDB-LWN / PPDB-LWN Specifications:
Model: PBDB-LWN / PPDB-LWN
Brand: SUN HYDRAULICS
Product Type: Pilot-operated pressure reducing valve (PBDB) / Pilot-operated reducing/relieving valve (PPDB)
Capacity: 40 L/min (10 gpm)
Cavity: T-11A
Maximum Operating Pressure: 350 bar (5000 psi)
Adjustment Range: 10.5–315 bar
Control Pilot Flow: 0.11–0.16 L/min
Adjustment Turns: 5 turns from min. to max. setting
Valve Hex Size: 22.2 mm (7/8 in.)
Installation Torque: 41–47 N·m (30–35 lbf·ft)
Adjustment Screw Hex Size: 4 mm
Weight: Approx. 0.16 kg (0.35 lb)
Seal Kit: Buna-N 990011007
PBDB-LBN / PPDB-LBN Specifications:
Model: PBDB-LBN / PPDB-LBN
Brand: SUN HYDRAULICS
Product Type: Pilot-operated pressure reducing valve (PBDB) / Pilot-operated reducing/relieving valve (PPDB)
Capacity: 40 L/min (10 gpm)
Cavity: T-11A
Maximum Operating Pressure: 350 bar (5000 psi)
Adjustment Range: 3.5–105 bar
Control Pilot Flow: 0.11–0.16 L/min
Adjustment Turns: 5 turns from min. to max. setting
Valve Hex Size: 22.2 mm (7/8 in.)
Installation Torque: 41–47 N·m (30–35 lbf·ft)
Weight: Approx. 0.16 kg (0.35 lb)
Seal Kit: Buna-N 990011007
PBDB-LAN Specifications:
Model: PBDB-LAN
Brand: SUN HYDRAULICS
Product Type: Pilot-operated pressure reducing valve
Capacity: 40 L/min (10 gpm)
Cavity: T-11A
Maximum Operating Pressure: 350 bar (5000 psi)
Adjustment Range: 3.5–210 bar
Control Pilot Flow: 0.11–0.16 L/min
Valve Hex Size: 22.2 mm (7/8 in.)
Installation Torque: 41–47 N·m (30–35 lbf·ft)
Weight: Approx. 0.16 kg (0.35 lb)
PBFB-LAN Specifications:
Model: PBFB-LAN
Brand: SUN HYDRAULICS
Product Type: Pilot-operated pressure reducing valve
Capacity: 80 L/min (20 gpm)
Cavity: T-2A
Maximum Operating Pressure: 350 bar (5000 psi)
Control Pilot Flow: 0.16–0.25 L/min
Adjustment Turns: 5 turns from min. to max. setting
Valve Hex Size: 28.6 mm (1 1/8 in.)
Installation Torque: 61–68 N·m (45–50 lbf·ft)
Adjustment Screw Hex Size: 4 mm
Weight: 0.29 kg (0.64 lb)
Seal Kit: Buna-N 990202007
Key Technical Advantages
1. Pilot-Operated Pressure Control with Exceptionally Flat Pressure/Flow Characteristics
All models feature pilot-operated construction. The pilot stage controls the main spool, with the main stage orifice protected by a 150 micron stainless steel screen. Compared to direct-acting valves, pilot-operated valves exhibit exceptionally flat pressure/flow characteristics, excellent stability, and very low hysteresis. Reduced pressure remains constant even under significant flow fluctuations.
2. PPDB Series — Integrated Reducing and Relieving Design (PPDB-LWN / PPDB-LBN)
The PPDB series adds full-flow relief capability to the PBDB reducing function. When reduced pressure at port 1 rises abnormally due to load changes, the valve automatically relieves full flow from port 1 to port 3 (tank), preventing downstream overpressure. This integrated design eliminates external relief valves and simplifies manifold layouts.
3. Port 3 Pilot Pressure 1:1 Additive Function
Pressure at port 3 is directly additive to the valve setting at a 1:1 ratio, not to exceed 350 bar. This feature allows external pilot signals to remotely adjust reduced pressure—by controlling pressure at port 3, the outlet pressure setting can be changed without touching the adjustment screw, ideal for remote pressure control and load-sensing systems.
4. Floating Style Construction — Zero Binding
Sun Hydraulics’ patented floating style construction allows the spool and sleeve to float slightly within the cavity, automatically compensating for concentricity deviations caused by excessive installation torque or cavity machining variations. This design dramatically reduces the risk of internal parts binding, ensuring reliable operation under all installation conditions.
5. Physical Interchangeability for Simplified Spare Parts Management
All three-port pressure reducing and reducing/relieving cartridges are physically interchangeable—same flow path, same cavity for a given frame size. PBDB and PPDB series of the same frame size can be directly interchanged in the same manifold position without modifications.
6. 150 Micron Stainless Steel Screen Protects Main Stage Orifice
The main stage orifice is protected by a 150 micron stainless steel screen. This design effectively prevents微小 particles from blocking the orifice, ensuring stable pilot control pressure and long-term reliable operation.
7. Multiple Pressure Ranges and Seal Options
Offers multiple pressure adjustment ranges—LAN (3.5–210 bar) , LBN (3.5–105 bar) , LWN (10.5–315 bar) —flexibly adapting to different system pressure requirements. Standard Buna-N seals for mineral oil systems; optional EPDM seals for phosphate ester fluid systems. Corrosion-resistant options available with /AP (stainless steel) or /LH (zinc-nickel plated) external components.
Application Areas
PBDB Series (2-Way Reducing Valve, T-11A Cavity):
Construction Machinery — Subsystem pressure control using a single pump source (e.g., pilot control circuits vs. main working circuits)
Injection Molding Machinery — Pressure staging for injection and clamping circuits
Hydraulic Presses and Forging Equipment — Pressure switching for slide advance and return
Industrial Hydraulic Systems — Various applications requiring reduction of main system pressure for sub-circuits
PPDB Series (Reducing/Relieving Valve, T-11A Cavity):
Load-Sensing Hydraulic Systems — Remote adjustment of load-sensing pilot signals
Multi-Pressure Hydraulic Systems — Multiple working pressures from a single pump with independent overpressure protection
CNC Machine Tools — Pressure control for hydraulic clamping and unclamping with integrated relief
Test Benches and Test Equipment — Pressure regulation requiring precise control with downstream protection
PBFB Series (High-Flow 2-Way Reducing Valve, T-2A Cavity):
Large Construction Machinery — High-flow pilot and auxiliary circuit pressure control for excavators and loaders
Metallurgical Equipment — Pressure staging for rolling mill hydraulic systems
Marine and Port Machinery — Pressure regulation for high-flow hydraulic systems on winches and cranes
Expert Maintenance Tips
1. Installation Guidelines
PBDB/PPDB series fit T-11A cavity with installation torque of 41–47 N·m (30–35 lbf·ft) .
PBFB-LAN fits T-2A cavity with installation torque of 61–68 N·m (45–50 lbf·ft) .
Sun Hydraulics floating style construction compensates for some installation variations, but standard cavity tooling is still recommended to ensure cavity dimensions and tolerances meet specifications.
2. Reverse Flow Considerations
Full reverse flow from reduced pressure (port 1) to inlet (port 2) may cause the main spool to close.
If reverse free flow is required in the circuit, add a separate check valve to the circuit.
3. Pilot Pressure and Port 3 Back Pressure
Pressure at port 3 is directly additive to the valve setting at a 1:1 ratio, not to exceed 350 bar.
During system design, back pressure at port 3 directly affects the reduced pressure setting—every 1 bar increase in back pressure increases the outlet pressure setting by 1 bar.
4. Pilot Flow Consumption
PBDB/PPDB series control pilot flow: 0.11–0.16 L/min.
PBFB-LAN control pilot flow: 0.16–0.25 L/min.
If pilot flow consumption is critical for the system, consider using direct-acting reducing/relieving valves.
5. Seal Material Selection
6. Pressure Adjustment
7. Periodic Maintenance Inspection
Inspect the valve body for external oil leakage every 2,000 operating hours or at least annually.
If reduced pressure instability or slow response is observed, first check system fluid cleanliness and verify the 150 micron stainless steel screen is not blocked.
The main stage orifice is protected by a stainless steel screen, but screen condition should still be checked after extended use.
