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Meter out pressure compensator
Sandwich plate design
Type SCA... /Series 2X
Sizes 16, 25 up to 315 bar up to 325 L/min
RE 29 247/02.96
RE
29 247/02.96
Replaces: 09.87
– Sandwich plate design
– Load compensation in lines A + B, or only A, or only B,
used in conjunction with a pilot operated proportional
directional valve
– Leak tight closing in one or both service lines
– Connection dimensions to DIN 24 340 Form A,
ISO 4401 and CETOP-RP 121 H
K 3807/5
Type SCA 16 CZ2X/..
Description of function, Section
This valve is used in conjunction with a proportional directional
valve to form a meter out flow control circuit to control both
negative and positive loads.
Service ports A2 and B2 may be locked to support loads.
The value and direction of an oil flow can be set at the
potentiometer controlling the proportional directional valve.
If, for example, the pump is directed to port A1, oil flows via valve
set (2.1) to the actuator. Valve set (2.1) in this case, functions as
a non return valve. At the same time, a pilot oil flow is taken from
the main oil flow, and passes through the pilot piston (4.1) (acting
as a pressure compensated flow control), into chamber (5). This
pilot flow causes a pressure to build up at the relief valve (3), and
an the pilot piston (4.2), via orifice (7), on the B side.
In addition, the outlet of the pressure relief valve is connected to
the T port of the main valve.
The unloading poppet (8) thus cuts off the connection to the load
pressure. The pressure before the proportional valve is then
present in chamber (9) via the pressure take off at the unloading
poppet (8). Pressure is also present on both the full bore and the
annulus sides of the opening piston (4.2)
The pressure drop from B to T via the proportional directional
valve is thus held constant. This pressure drop in controlled by
land (10), and is the pressure in chamber (11) minus the spring
(12). The force of spring (13) plays no part at this stage.
When the pump pressure is directed to port B, valve set (2.1)
operates in exactly the same way in port A.
Detail "Z"
Type SCA 16 CZ2X/..
2/6
RE 29 247/02.96
Simplified symbols (Subscripts: 1 = Component Side, 2 = Mounting Interface Side)
Type SCA.. AZ2X/... Type SCA.. BZ2X/... Type SCA.. CZ2X/...
PX A B Y
T
1
2
L PX A B Y
T
1
2
L
1
2
PX A B Y
T
L
Typical circuit (detailed)
Load
Ordering Code
Meter out pressure compensator = SCA
Size 16 = 16
Size 25 = 25
Operation in line A = A
Operation in line B = B
Operation in lines A and B = C
Further details in clear text
M = NBR seals, suitable for
mineral oil to DIN 51 524 (HL, HLP)
V = FPM seals, suitable for
phosphate ester (HFD-R)
2X = Series 20 to 29 (20 to 29: installation
and connection dimensions remain unchanged)
Z = Sandwich plate design
SCA Z 2X
*
Operation in lines A and B
Special insulations on request!
Valve types which result from the order variations in
the grey-shaded areas are available at short notice!
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0
5
10
15
20
25
30
35
40
80 120 160 200 240 280 325
0
5
10
15
20
25
30
35
20
40 60 80 100 120 130
Technical Data (For applications outside these parameters, please consult us!)
}
Response in %
1
)
q
V min
to
q
V max
q
V max
to
q
V min
(type 4WRZ... + type SCA...)
T
u
+
T
g
in ms
T
u
+
T
g
in ms
0 to 100 270 80
50 to 75 100 70
0 to 100 280 200
50 to 75 130 100
Pilot oil volume
from pressure relief valve to tank:
for size 16 max. 1,8 L/min
for size 25 max. 2,5 L/min
Pressure/Flow relationship:
see diagrams pages 4 and 5
Fluids: Mineral oil to DIN 51 524 (HL, HLP)
Phosphate ester (HFD-R)
Maximum degree of contamination of the fluid
to NAS 1638 classes 7 to 9. We therefore recommend
a filter with a minimum retention rate of
β
10
≥75.
Fluid temperature
range: – 20 to + 70 °C
Viscosity range: 15 to 380 mm
2
/s
Installation position: optional
Weights: Size 16 6,0 kg
Size 25 11,3 kg
Note: Good settling characteristics are achieved with systems having natural frequencies > 4 Hz.
Operation Curves (measured at
ν
= 41 mm
2
/s and
t
= 50 °C)
Minimum differential pressure
∆
p
=
f (q
V
)
Start of control Start of control
Size 16 Size 25
2
)
p
min
=
p
M3b
–
p
M4
(For test points M3b, M4 see page 2)
Flow compen-
sating range
Flow compen-
sating range
RE 29 247/09.87
Size
16
25
1
) 100 % input signal = 700 mA Solenoid current
T
g
= setting time
T
u
= signal delay
Flow in L/min Flow in L/min
Pressure difference
p
min
2
) in bar
Pressure difference
p
min
2
) in bar
Operating Pressure: – Ports A1, A2, B1, B2,
p
max
315 bar
Warning: When used with single rod cylinders,
beware of intensification.
– Ports T1, T2 separat to tank
– Ports X1, X2 max. 315 bar
– Ports Y1, Y2 max. 30 bar
Flow: Size 16 max. 130 L/min
Size 25 max. 325 L/min
Min. pressure differential: see diagrams
Flow resistance: pages 3,4 and 5
16 150
Dynamic charact: (measured at a load pressure of 150 bar with prop. valve type 4WRZ E …)
25 325
Resistance to flowResistance to flow
4/6
0
2
10 20 30 40 50 60 70 80 90 100 110 120 130
4
6
8
10
12
14
16
1
2
Flow/Pressure relationship
q
V
=
f (p
E
+ command value); command value constant
Resistance to flow
∆
p
=
f (q
V
)
1
) see cicuit page 2
Flow controlling - command value/Flow
q
V
=
f
(command value)
Size 16
1 Resistance in flow:
Non return valve function
(Test point: M2a - M2b or
M3a - M3b)
1
)
2 Resistance to flow at
proportional directional valve
input land
(Test point: M1 - M2a or
M4 - M3a)
1
)
Note:
In the “one side” model, “no
compensator in A”,the
resistance to flow in the “A” line
M1 - M2a (8 bar).
In the “one side” model “no
compensator in B”, the
resistance to flow in the “B” line
M3a - M4 (8 bar).
p
E
-Test point M3b
1
) in
ports A and B.
Note:
The diagram refers to a
spool for 150 L/min
nominal flow (Valve
Type 4WRZ 16 E150..)
Meter out pressure compensator Type SCA 16...
with proportional directional valve
Type 4WRZ 16 E100...
Type 4WRZ 16 E150...
(P → A, B → T)
Curve
q
V
=
f
(command value) in ports A and B;
p
E
= 50 bar constant at test point M3b
1
)
RE 29 247/09.87
Flow in L/min
Flow in L/min
Flow in L/min
Operating pressure
p
E
in bar at test point: M3b
1
)
Pressure difference in bar
0
130
20
20
40
60
80
100
120
40 60 80 100
0
130
20
40
60
80
100
120
40 80 120 160 200 240 280 315300
87 % = 610 mA
^
80 % = 560 mA
^
70 % = 490 mA
^
60 % = 420 mA
^
50 % = 350 mA
^
Opening point 32
command value in %
Operating Curves (measured at
ν
= 41 mm
2
/s and
t
= 50 °C)
5/6
1
) see circuit on page 2
Resistance to flow
∆
p
=
f (q
V
)
Size 25
1 Resistance to flow:
Non return valve function
(Test point: M2a - M2b or
M3a - M3b)
1
)
2 Resistance to flow at
proportional directional valve
input land
(Test point: M1 - M2a or
M4 - M3a)
1
)
Note:
In the “one sided” model, “no
compensator in A” the
resistance to flow in the “A” line
M1 - M2a (8 bar).
In the “one sided” model, “no
compensator in B” the
resistance to flow in the “B” line
M3a - M4 (8 bar).
p
E
-Test point M3b
1
) in
ports A and B.
Note:
The diagram refers to a
spool for 325 L/min
nominal flow (Valve
Type 4WRZ 25 E325...)
Flow controlling - input signal/Flow
q
V
=
f
(command value)
Meter out pressure compensator Typw SCA 25... with
proportional directional valve
Type 4WRZ 25 E325...
(P → A)
Curve
q
V
=
f
(command value)
p
E
= 50 bar constant at test point M3b
1
)
Flow/Pressure relationship
q
V
=
f (p
E
+ command value); command value constant
Operating Curves (measured at
ν
= 41 mm
2
/s and
t
= 50 °C)
RE 29 247/09.87
Flow in L/min
Flow in L/min
Pressure difference in bar
Flow in L/min
0
5
325
10
15
20
25
30
35
40
1
2
40 80 120 160 200 240 280
0
40
20
80
120
160
200
240
40 60 80 100
280
325
0
40
40
80
120
160
200
240
80 120 160 315
280
325
200 240 280 300
100 % = 700 mA
^
80 % = 560 mA
^
70 % = 490 mA
^
60 % = 420 mA
^
50 % = 350 mA
^
Operating pressure
p
E
in bar at test point: M3b
1
)
Opening point 32
command value in %
6/6
Size 16
1 Nameplate
2 6 thro' holes for
fixing screws
3 R-rings for ports A2, B2, P2, T2
Size 16 R-ring 22,53 x 2,3 x 2,62
Size 25 R-ring 27,8 x 2,6 x 3,0
4 R-rings for ports X2, Y2, L2
Size 16 R-ring 10 x 2,0 x 2,0
Size 25 R-ring 19 x 3,0 x 3,0
5 Locating pin
6 Drilling for locating pin
7 Valve operational in port A
(Type SCA.. AZ2X/...)
8 Valve operational in port B
(Type SCA..BZ2X/...)
9 Valve operational in port A and B
(Type SCA..CZ2X/...)
10 Pressure relief valve
Required surface finish of
mating piece
RE 29 247/02.96
Size 25
0,01/100mm
R 4
max
Unit dimensions (in mm)
Mannesmann Rexroth Limited
Cromwell Road, St. Neots,
Huntingdon, Cambs. PE19 2ES
Tel: (01480) 476041
Fax: (01480) 219052
Mannesmann Rexroth GmbH
D-97813 Lohr am Main
Jahnstraße 3-5 • D-97816 Lohr am Main
Telefon 0 93 52 / 18-0 • Telefax 0 93 52 / 18-10 40
Telex 6 89 418-0
The specified data is for product description purposes only and may not be deemed to be
guaranteed unless expressly confirmed in the contract. All rights reserved – Subject to revision
