HA 5202
12/2014
M20 x 1,5 • p
max
350 bar • Q
max
30 L/min
Overcentre Valve
Fully Balanced
SOB5A-Q3/l
q
The valve prevents runaway in the event of a nega
-
tive load
q
Load-holding without leakage
q
Pressure relief function protecting the actuator
against overload and pressure peaks
q
When installed into the actuator the valve can be
used as a hose burst valve
q
When used as pressure relief the check valve will
act as an anti-cavitation valve
q
Relief setting is unaffected by back pressure
q
The valve should be mounted as close as possible
to the actuator
q
Fits the same cavity as the Q3 check valve
1
2
3
VENT
Replaces
HA 5202 7/2008
The valve consists of a seat by-pass, relief valve fitted
with an auxiliary control with a differential piston and
by-pass single-way valve serving for reverse direction
of flow. The liquid is flowing through the single-way valve
from the channel (2) to the channel (1) with a small
pressure drop. In the opposite direction the single-way
valve on the rear side of which a gate valve seat is fitted is
pressed through the action of a spring and the load
pressure against the spring-loaded valve gate valve.
In this way the valve is nearly closed hermetically.
If the pressure in the channel (1) exceeds a set up value
of the spring force the gate valve is pressed out of
the seat and the overpressure in that case is relieved into
channel (2). For ensuring the function of holding the load
the spring force should be set up to a value by 30 %
higher when compared to an expected pressure exerted
by the load.
If the load has to be moved it is possible to ensure it with
the help of so called auxiliary control from the channel (3)
by introducing already certain control pressure.
The control pressure is calculated in the following way:
Control pressure =
The ratio of control designates a ratio of surfaces
of the differential slide valve cross-section area and its
seat. Therefore, the necessary control pressure
for opening the valve does not correspond to
the difference between the set up pressure and load
pressure however; it corresponds to the ratio of this
difference and the control ratio. In the formula as
mentioned above it is necessary to take into
consideration that in differential cylinders it is necessary
to add to the control ratio also the appropriate ratio
of piston surfaces in the direction of movement.
As soon as the control pressure attains a necessary
value the differential gate valve is moved out from
the seat and then the way from the channel (1) to
the channel (2) is released. If now the load tries to
accelerate and be fast as for the oil supply the supply
pressure decreases, therefore, also the control pressure
in the channel (3) is decreased. The spring force tries to
shut off the valve again, therefore, in consequence
of which the flow from the consumer decreases and
the inlet pressure to the consumer increases again.
In this way it is ensured a constant inlet pressure by
means of which the movement of the load can be
controlled.
Dynamic pressures in the outlet do not influence
the set up value thanks to a special arrangement
of the slide valve. However, it is necessary to take care
of the fact the control channel is independent
on the dynamic pressure.
As for appropriate basic surface finish the external parts
are zinc coated.
Functional Description
set up pressure – load pressure
ratio of control
2
HA 5202
Ordering Code
SOB5A-Q3/l
Overcentre valve
Fully Balanced
Pilot ratio
Standard 5:1
5
Technical Data
Cavity M20 x 1,5
Maximum flow L/min 30
Max. pressure bar 270
Max. input pressure bar 350
Pressure drops bar see Dp - Q characteristics
Hydraulic fluid Hydraulic oil (HM, HV) according to DIN 51524
Fluid temperature range °C --20 ... +90
Viscosity mm
2
/s 20 ... 400
Maximum degree of fluid contamination according to ISO 4406, Class 21/18/15
Weight kg 0,14
Maximum valve tightening torque
in valve body or in control block
Nm 45
+2
Mounting position Unrestricted
Dp-Q Characteristics Measured at n = 40 mm
2
/s
0 1020304050
50
40
30
20
10
FREE FLOW
PILOT OPEN
750
600
450
300
150
0
0 2.5 5 7.5 10 12.5
Pressure p barD []
Flow Q L/min[]
Flow Q US GPM[]
Pressure p PSID []
Seals
No designation NBR
3
HA 5202
Dimensions Measurements in millimeters
Cavity Measurements in millimeters
3
2
1
ATMOSFÉRA
6HR4
6HR25.4 (1")
M20 x 1,5-6g
47.0 MAX
42.5
HEX 4.0
VENT
HEX 25.4
M20 x 1,5-6g
A
Æ
Æ
Æ
16.05
16.00
Æ
15.00 MAX
17.55
17.50
M20x1.5-6H
21.90
21.80
Æ
30
15°
13.5
2.80
2.40
30.0
11.0
43.0
45°
13.5
30.0
40.0
Æ
8.0
MAX
Æ
4.0
1.6
0.08
1.6
0.3
1.6
1.6
Æ
0.05
-A-
Æ
0.08
B
A
B
Æ
0.08
30°
30°
A
4
HA 5202
Caution!
The packing foil is recyclable.
The technical information regarding the product presented in this catalogue is for descriptive purposes only. It should
not be construed in any case as a guaranteed representation of the product properties in the sense of the law.
ISO A
The use of aluminium bodies is limited to a maximum operating pressure of 210 bar.
Dual body without valve
Material Ports Port size Type code
Aluminium
C1, C2, V1, V2 G3/8 SB-Q3-0203AL
C1, C2, V1, V2 SAE 8, 3/4-16 SB-Q3-0204AL
Steel
C1, C2, V1, V2 G3/8 SB-Q3-0203ST
C1, C2, V1, V2 SAE 8, 3/4-16 SB-Q3-0204ST
Valve Bodies Measurements in millimeters
Spare Parts
Seal kits on request.
Body without valve
Material Ports Port size Type code
Aluminium
1, 2 G3/8
SB-Q3-0103AL
3 G1/4
1, 2 SAE 8, 3/4-16
SB-Q3-0104AL
3 SAE 6, 9/16-18
Steel
1, 2 G3/8
SB-Q3-0103ST
3 G1/4
1, 2 SAE 8, 3/4-16
SB-Q3-0104ST
3 SAE 6, 9/16-18
Subject to alteration without notice!
ARGO-HYTOS s.r.o. CZ - 543 15 Vrchlabí
Tel.: +420-499-403111, Fax: +420-499-403421
E-mail: sales.cz@argo-hytos.com
www.argo-hytos.com
x OTVOR 9
