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MODEL

PBDF8

Pilot-operated, pressure reducing main stage with drilled piston orifice and

integral T-8A control cavity

SERIES 1 / CAPACITY: 40 L/min. / CAVITY: T-11A

(W)BIAS PRESSURE

W 100 psi (7 bar)

D 25 psi (1,7 bar)

(N)SEAL MATERIAL

N Buna-N

V Viton

NOTE: DATA MAY VARY BY CONFIGURATION. SEE CONFIGURATION SECTION.

This valve is a normally open modulating element that incorporates an integral pilot control cavity. The pilot control

cavity will accept any T-8A pressure control cartridge. The valve reduces a high primary pressure at the inlet (port 2)

to a constant reduced pressure at port 1. The pilot cartridge's setting determines the difference in pressure between

reduced pressure (port 1) and the drain (port 3).

TECHNICAL DATA

Cavity T-11A

Series 1

Capacity 40 L/min.

Maximum Operating Pressure 350 bar

Control Pilot Flow 0,11 - 0,16 L/min.

Pilot Control Cavity T-8A

Valve Hex Size 22,2 mm

Valve Installation Torque 41 - 47 Nm

Seal kit - Cartridge Buna: 990011007

Seal kit - Cartridge Polyurethane: 990011002

Seal kit - Cartridge Viton: 990011006

Model Weight 0.10 kg.

sunhydraulics.com/model/

PBDF8

Model Code Example: PBDF8WNCONFIGURATION OPTIONS

 2025 Sun Hydraulics 2 of 2

TECHNICAL FEATURES

These valves have the main stage orifice drilled into the piston rather than a staked-in orifice. This allows the valve to survive physically demanding applications.

All three-port pressure reducing and reducing/relieving cartridges are physically interchangeable (i.e. same flow path, same cavity for a given frame size). When

considering mounting configurations, it is sometimes recommended that a full capacity return line (port 3) be used with reducing/relieving cartridges.

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, consider adding a

separate check valve to the circuit.

Pilot operated valves exhibit very low dead-band transition between reducing and relieving modes.

Pilot operated valves exhibit exceptionally flat pressure/flow characteristics, are very stable and have low hysteresis.

Pressure at port 3 is directly additive to the valve setting at a 1:1 ratio and should not exceed 5000 psi (350 bar).

Maximum inlet pressure is determined by the bias spring. The D spring is tested with 2000 psi (140 bar) maximum differential pressure and the W spring is tested

with 5000 psi (350 bar) maximum inlet pressure.

NOTE: With the -8 control option, the main stage valve should first be installed to the correct torque value. The T-8A pilot control valve should then be installed into

the main stage valve to its required torque value.

The -8 control option allows the pilot control valve to be incorporated directly into the end of the relief cartridge via the T-8A cavity. These pilot control cartridges are

sold separately and include electro-proportional, solenoid, air pilot, and hydraulic pilot operation. See Pilot Control Cartridges.

Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge

machining variations.

PERFORMANCE CURVES

RELATED MODELS

PBDF Pilot-operated, pressure reducing valve with drilled piston orifice