5-11
GFG2_UK.INDD CM_26.10.2009
Catalogue HY11-3500/UK
2 Way Flow Control Valve
Series GFG2
Parker Hannifin GmbH
Hydraulic Controls Division
Kaarst, Germany
5
Characteristics
2 way flow control valves are used to provide pressure
compensated flow. The valve design compensates tem-
perature variations to a certain extent.
Optionally the flow from A to B can be blocked by ex-
ternal pilot pressure applied to port P (option X). This
can be used to avoid unintended initial movements of
actuators.
The GFG is optionally equipped with a built-in check valve
for the return flow.
Design
The 2 way flow control valves are fitted with a triangular
flow restrictor and a subsequent pressure compensator.
The setting of the flow rate can be locked by a key lock
in the adjusting knob against unauthorised adjustment
(option C).
Function
The fluid enters through port A through the flow restrictor.
Downstream of the flow restrictor the pressure compen-
sator is located. The control edges are provided by four
radial bores in the poppet, which are fully open to port B
in the neutral position.
This can cause a short non-compensated flow when the
valve is initialized.
Optionally the compensator spool can be held in closed
position by external pilot pressure in port P (option X).
The flow adjustment is done via the flow resistor which
is adjusted by the hand knob. The adjusting angle of the
hand knob is 270°.
Features
• Flowrateindependentofpressureandtemperature
• Availablefor7differentowrates
• Goodneadjustment
• Optionalreverseowcheckvalve
• Turnknobwithkeylock(optionC)
Note
Rectifier plate and subplates see 'Accessories' at the
end of this chapter.
GFG 2 PK
GFG 2 PKC
5-12
GFG2_UK.INDD CM_26.10.2009
Catalogue HY11-3500/UK
2 Way Flow Control Valve
Series GFG2
Parker Hannifin GmbH
Hydraulic Controls Division
Kaarst, Germany
5
Technical Data / Ordering Code
Seal2 way flow
control valve
GFG
Nominal
Size
NG6
Pressure
compen-
sated
Locking
option
Check
valve
PK
Flow
2
Pilot
port
Design
series
(not required
for ordering)
Code Check valve
omit
Without
check valve
C
With
check valve
Code
Control of the
press. differential
valve
omit Standard internal
X* External
Code Flow [l/min]
0.6 0.015 to 0.6
1.0 0.015 to 1.0
1.6 0.015 to 1.6
3.2 0.025 to 3.2
6.3 0.025 to 6.3
12.0 0.080 to 12.0
18.0 0.080 to 18.0
Code Seal
omit NBR
V FPM
Code Locking option
omit
Standard
without lock
S
With
2H (E10) lock
Design Orifice, infinitely variable, pressure-compensated
Actuator Manual flow rate adjustment
Mounting type ISO 6263
code: ISO 6263-AB-03-4-B
Mounting position unrestricted
MTTF
D
value [years] 150
Weight [kg] 1.1 (without subplate)
Fluid Hydraulic oil acc. to DIN 51524/525
Fluid temperature [°C] Max. 70
Ambient temperature [°C] -25...+50
Viscosity range [cSt] / [mm²/s] 2.8...400
Filtering [µm] ISO 4406 (1999); 18/16/13
Min. pressure difference [bar] 5 (GFG*1.6/3.2), 8.5 (GFG*6.3/12/18)
Operating pressure [bar] A; B = 315 , P = 5 (GFG*, GFG*C), A, B, P = 160 (GFG*X)
Effect of pressure on Q
max
at p = 160 bar [%] ± 2 (GFG*1.6/3.2/6.3/12), ± 2.5 (GFG*18)
Flow direction
A → B
B → A
Flow control function
Throttle function or free flow through check valve
Ordering code
* only in combination with inte-
grated check valve.
Technical data
5-13
GFG2_UK.INDD CM_26.10.2009
Catalogue HY11-3500/UK
2 Way Flow Control Valve
Series GFG2
Parker Hannifin GmbH
Hydraulic Controls Division
Kaarst, Germany
5
Bolt kits (Cylinder head DIN 912-12.9 not included)
Nom. size
Valve
Valve
model
Quantity
Tightening
torque [Nm]
Valve without rectifier plate Valve with rectifier plate
Dimensions Order No. Dimensions Order No.
NG 6 GFG2 2 8.1Nm 2xM5x60 BK380 2xM5x100 BK466
Nom. size
Valve
Valve
model
Ports
Dimensions
Ø-inner x cord thickness
Quantity
Seal kits
NBR FPM
NG 6 GFG2 A and B 9x1.5 3 SK-GFG2 SK-GFG2 FPM
O-rings for sealing the connecting surface
Performance curves
Changes in pressure cause a change of pre-set flow rate.
Flow rate deviations a Q
max
: ± 2%
Performance Curves / Dimensions
Dimensions
All characteristic curves measured with HLP46 at 50°C.
5-14
GFG2_UK.INDD CM_26.10.2009
Catalogue HY11-3500/UK
2 Way Flow Control Valve
Series GFG2
Parker Hannifin GmbH
Hydraulic Controls Division
Kaarst, Germany
5
Accessories
Measured with HLP46 at 50°C.
Sandwich rectifier plate
If a 2 way flow control valve is used in combination with
a rectifier plate the valve can be used for meter-in and
meter-out flow control of an actuator.
Design
The intermediate rectifier plate is designed with 4 identi-
cal, symmetrically arranged check valves. Thus the dif-
ferential pressure is the same in both flow directions.
Dimension tolerances
* : ± 0.1mm
others : ± 0.2 mm
holes and silhouette of
valve body : untoleranced dimension
Ordering code: HR OA 06 C
Dimensions
Connections Dimensions required units
A, B 12 x 1.5 2
Ordering code
SPD 22 B 910 P, A, B and T = G1/4
SPD 23 B 910 P, A, B and T = G1/8
O-ring for sealing the connecting surface
(not included)
Subplates
1)
1)
Details see chapter 12, series SPD