Pressure Relief Valves

//Direct Operated, Max. 400BAR/5800PSI Pressure, DBD6,10 pressure Relief Valve

Direct Operated, Max. 400BAR/5800PSI Pressure, DBD6,10 pressure Relief Valve

Direct Acting Relief Valve

PRODUCT TYPE: DBD Direct Acting Relief Valve
VALVE SIZE: DBD 6, 8, 10, 15, 20, 25, 30
CONTROL METHOD: Direct Operated
APPLICATION Hydraulic Machines
CONNECTION TYPE: Threaded Connection
Relief Valve Block G Type
Hydraulic Relief Valve Block P Type
– Cartridge design, direct operated
– Standard threaded connection, 97/23/EC tested
– Hexagon socket threaded pin covered by protective cap

DBD Direct Operated Relief Valve PDF

DBD6, 8, 10, 15, 20 direct acting relief valve is used for limiting the system pressure by adjusting handle directly. This valve is used for the higher pressure machine with small flow rate, such like an elevator as a device for safety protection.

The Key part of direct acting relief valve DBD type is the spring, we are using high quality of import spring raw materials, there is a little spring deformation after long term and under higher pressure. Finotek DBD direct acting relief valve is installing all kinds of hydraulic units or system as pressure regulation or safety valve, the important items for sealing the pressure are made by high strength steel and all hardened after finishing. The DBD valve is threaded connection, but it can be changeable to subplate mounting by blocks.The max. adjustment pressure can reach to 40Mpa of DBD series valves.

Direct Action Relief Valve -DBD Structure

Picture A-1 & A-2: Cushioning Spool, Damping Piston Of Direct Acting Relief Valve With Cartridge Style
1. Spring seat   |   2. Cushion spool    |   3. Pin

The DBD type is the cushioning spool, damping piston of direct acting relief valve with cartridge connections. It is important to understand the DBD series by the part of cushioning spool, please see the Picture A-2, the enlarged head part view of the structure.

The DBD relief valve seat against cushion spool not only has dynamic hydraulic damping effect when the cushioning spool in a closed or open position so that to improve the valve operation stability, but also is used to ensure the straight movement of cushion spool in order to improve the static characteristics of the DBD direct acting relief valve.

Due to cone shape between the connection of cushion spool and seat, therefore, the steady fluid force of flow in inlet and outlet port keeps equilibrium when the cushion spool in an open position. The part of pin “3” has and annular groove for switching the flow direction at outlet port and generated a jet force against the force from the valve spring, to counteract the spring increment force caused by increasing flow rate, so that the inlet pressure is less affect to flow changes and obtaining a pressure – flow characteristics with high-pressure and large flow level, which will increase the amount of flow rate through the DBD pressure relief valve. In addition, the seat supports a larger diameter spring, and for higher pressure, to facilitate spring structure design and extend the presetting pressure range of DBD direct acting relief valve.


Valve Ordering Code

Example (Normal code): “FT-DBDS 6 K 1X/315 ”
Explanation As Below:

FT- DBD S 6 K 1X / 315    
(1) (2) (3) (4) (5) (6) (7) (8)

(1) Producer code= FT
(2) H= Hand wheel
  S= Screw adjustment and protective cap
(3) Size= 6; 8; 10; 15; 20; 25; 30
(4) K= Cartridge mounting
  G= Threaded connections
  P= Subplate mounting
(5) 1X= Valve series

(6) 315= Pressure presetting Bar(Psi):315(4600)
  25= Pressure presetting Bar(Psi):25(365)
  50= Pressure presetting Bar(Psi):50(725)
  100= Pressure presetting Bar(Psi):100(1450)
  200= Pressure presetting Bar(Psi):200(2900)
  400= Pressure presetting Bar(Psi):400(5800)
(7) No code= Inch thread
  2= Metric thread
(8) No code = NBR seals for petroleum oil
  V = FPM seals for phosphate ester

Valve Technical Information

Main Raw Materials: 45# Carbon Steel(Valve House)
Power: By hydraulic
Brand: Finotek or OEM
Max. Operation Pressure: 6 Pressure presetting stages
Max. Flow Rate: 50-350L/min.

Oil Medium Temperature: -30 to +80(°C)for NBR O-rings
Oil Medium: Mineral oil as per DIN51 524, VDMA 24 568 or rapeseed oil, Viscosity 10 – 400 CST
Recommended Medium Filtration: ISO 4406 Standard, cleanliness class:20/18/15

DBD Valve Characteristic Curves


Valve Function Symbol


Valve Installation Dimensions


  D D1 D2 D3 L L1 L2 L3 L4 L5
6 M28×1.5 25H8 15 6 65 56.5±1 45 35 19 15
10 M35×1.5 32H8 18.5 10 80 67.5±1 52 41 23 18
20 M45×1.5 40H8 24 20 110 91.5±1 70 54 27 21
30 M60×2 55H8 38.75 30 140 113.5±1 84 60 29 23

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