SV2-16
Servo Valve
reliable low-maintenance cost-efficient
SV2-16
Servo V a lve
Operating principle: Servo valves are the most important components of each electrohydraulic control system. The rotary slide design with gap adjustment on which our development is based ensures minimum frictional loss, high repetitive accuracy and a large capacity range for single-stage valves. EMG rotary slide servo valves offer high reliability and maximum ease of servicing. This type of valve allows flushing for cleaning during operation (without oil escaping). Based on many years of experience with industrial applications using control hydraulics we have decided to equip the valves with a manual operation mechanism for function control and for setting-up.
The EMG range comprises servo valves with nominal sizes between NG 6 and NG 100 and a flow rate between 4 and 2,500 l/min with a pressure loss of 20 bar through the valve. To connect servo valves SV 2-16 standard connecting plates for directional valves NG 16 can be used. EMG servo valves are characterized by high reliability and best customer service.
Schematic of SV1-10 pilot control stage
EMG Automation GmbH specialises in the automation of continuous production processes in the metal, paper and plastics industries as well as in the foil and tyre industries. The company, which was established in 1946, is a leading provider of electro hydraulic control systems. Furthermore, they provide quality assurance systems for the manufacturing industry. The Automation division is the worldwide market leader in the supply of strip guiding systems to the metal industry, in particular for cold rolling mills and surface coating lines. The quality assurance systems of EMG Automation have been designed for non-contact measurement of material properties, roughness parameters as well as strip stabilization and are aimed at helping customers in the metal industry to optimize their production processes. Servo valve SV2-16
SV2-16
Servo V a lve
Function principle: In connection with a separate electronic control amplifier the servo valve SV2-16 controls proportional to an electrical input current of +/-300 mA a volumetric flow of 60/90/125 l/min at a valve pressure difference of 20 bar (10 bar each control edge). The pilot valve SV 1-10 is located on the valve block which pressurises the two faces of the piston slide valve via the internal outputs Av and Bv. The main stage consists of the central valve block with the piston slide valve fixed by springs and the two valve covers that are arranged at the front. One of these valve covers is provided with the assembly spot for the inductive position encoder. This ensures the position feedback of the main piston. The system made up of pilot valve SV 1-10, piston slide valve, inductive position encoder and control amplifier forms a
Valve SV1-10 with standard leak gaps Y1 and Y2
closed position control loop for positioning the piston slide valve. The volumetric flow is determined by the piston slide valve position and is proportional to the input voltage Ue of the control amplifier.
Technical features: large control distances, long service life, low leakage flow Valve can be cleaned during operation External mechanical manual control and performance monitoring Spring-centred rotary disc (zero position on power failure) Standard connections, standard plug
Frontal view of hydraulic manifold block
Flushing at the valve SV1-10: If the leak gap becomes blocked because of excess dirt in the oil, (recognisable by reducing response sensitivity, increased hysteresis), the fault can be cleared in most cases by flushing the valve out. For this the manual control must be carefully disengaged with a screwdriver in order to establish the absence of the dither signal. Then the flushing screw is loosened one quarter of one turn (ring spanner SW 19 mm). By this means throttle opening Y 2 opens without its normal adjustment being altered, and the leak gap is increased to approximately ten times its normal value. The resulting, increased oil flow flushes out the impurities in the tank ducting and the vibration signal can again be felt by the screwdriver.
After the flushing screw has been re-tightened (approx. 80 Nm), the leak gap set at the factory is again operative. During the tightening-up process, the availability of the dither signal is monitored in order to ensure that the rotary disc is not blocked by a large particle of dirt.
• long service life Customer benefit: Valve flushing during operation Appropriate even for low pressures Single-stage construction Warranty of least friction losses High repetition accuracy Huge range of performance at single-stage valves
3D sketch of servo valve SV2-16
100
Q %
100
p %
80
60
60 6%
40
40 1%
20
20
-100
-80
-60
-40
6%
1% 80
-20
20
40
60
-20
80 I %
100
-20
-16
-12
-8
-4
4
-40
-40
-60
-60
-80
-80
-100
-100
Volumetric flow curve (Overlap 1 % resp. 6 %)
8
12
-20
16 I %
20
Pressure curve (Overlap 1 % resp. 6 %)
Flushing / Filtering:
Emergency manual operation at SV1-10:
Before commissioning the valves, the hydraulic system must be flushed out. For this purpose, flushing plates should replace the servo valves (flushing plates SP 16 can be supplied complete with O-rings and fixing screws).
Turn the pivot pin in the end of the housing cover in the required direction with a screwdriver, until the positioning claw is located. Then turn it up to 5° further, against the centring spring resistance, depending on the flow required. Operation of the electrical control can be tested in the same way by bringing the positioning claw into contact without exerting any force with the screwdriver.
The following levels of contamination are allowed when using the EMG servo valve SV1-10: Level of contamination Filter type ISO 4406
16 / 12
NAS 1638
7
SAE
2
By the deflection of the pilot valve SV1-10 a volumetric flow is generated, which independent of the electrical position control loop causes a lateral movement of the main piston and thus induces a displacement of the hydraulic actuator.
• high accuracy Mechanical details: Servo valve
SV2-16/.. ± 5°
Angle of motion Leading edge
mm
Connections
60
90
125
±6
±6
±6
Hole layout A 16, DIN 24340 resp. ISO 4401-07-07-0-02
Weight
kg
Dynamic details at 100 bar and 30 % amplitude: Servovalve
SV2-16/..
60
90
125
Limiting frequency (3 dB)
Hz
37
37
37
90°-frequency
Hz
26
26
26
Equivalent time constants Tu Tg
ms ms
9.7 3.3
9.7 3.3
9.7 3.3
Q l/min
300 SV2-16/125
200
F dB
l/min
0 -3
0
10
-40
20
-80
30
-120
40
-160
50
-200
Φ
O
6
SV2-16/90
5 4
SV2-16/60 100
3 2 1
50
20
50
70
100
5 6 7 8 9 10
Ps bar
Relationship of volumetric flow to valve pressure drop at rated motion
20
50
100
f Hz
; 30 %
; 100 %
Electrical details: Servo valve
SV2-16/..
60
90
125
mA
± 300
± 300
± 300
mA mA
10 20
10 20
20 40
Resistance
Ω
40
40
40
Inductance
H
0.16
0.16
0.16
mA
± 600
± 600
± 600
mA mA
20 40
20 40
40 80
Resistance
Ω
20
20
20
Inductance
H
0.08
0.08
0.08
Connection 1-2:
Rated current Rated dither signal
50 Hz 150 Hz
Connection 1-3:
Rated current Rated dither signal
Enclosure
50 Hz 150 Hz
IP 65 (when plug and socket are assembled)
300
Ps bar
Relationship of leakage volumetric flow to operating pressure
Frequency response p S = 200 bar I / I N = 10 %
200
•huge range of performance Hydraulic details: Servo valve
SV2-16/..
Operating pressure range ps
SV2-16/..
60 Main stage
0...315 bar
Pilot control stage
30...315 bar
max. permissible reverse pressure pT
internal
Note: Apart from the usual nonreturn valve, no additional check valve should be used in the return line.
external
Rated flow QN at ∆ pN = 20 bar at ∆ pN = 70 bar
90
Main stage pT Pilot control stage p Y
30 bar 30 bar
Main stage pT Pilot control stage p Y
150 bar 30 bar
l/min 60 l/min 110
Control flow rate
internal external
Operating temperature range
-20...+80 °C
125
l/min l/min
4
l/min
min. 0.15 0.5
90 165
125 235
4
4
The following data are valid at rated dither signal Typical internal leakage flow Q O2 at ps = 100 bar; I = O mA; t = 50 °C; QA = O l/min; QB = O l/min SV2-16/../315/6 SV2-16/../315/1
max. 2 8
Hysteresis
% <0.5 <0.5
<0.5
Reversal error
% <0.2 <0.2
<0.2
Response sensitivity
% <0.2 <0.2
<0.2
Flow non-linearity
% <10
<10
<10
Flow assymmetry
%
<3
<3
Typical relative pressure
∆pL / ∆I /
IN
pS
SV2-16/../315/6 SV2-16/../315/1 Overlap
12
SV2-16/../.../1 0.5...2.5 % /6 4...8 %
Zero point temperature drift
50 °C
Recommended pressure medium 2)
Hydraulic oil H-L 46
Recommended filtering
ISO 4406 NAS 1638 SAE
2)
<3
other pressure on request: HFC, HFD
8 µm 16/12 7 2
Key to types:
Servo valve / double stage Standard size 16 (ISO 4401) Rated flow at Δp = 20 bar Operating pressure Pilot control Main stage
Overlap
l/min 60/90/125 bar min. 30 0-315
1% 6%
Piston type Pilot control I=Internal E=External EL=External + external leakage oil Design
Servo valve SV2-16
01
Automation GmbH Industriestraße 1 57482 Wenden Germany Phone: +49-2762-612-0 Telefax: +49-2762-612-384
[email protected] www.emg-automation.com
Group
.moving ahead.
EMG / ST-V / EN / Servoventil SV2-16 / Revision 00 / 07.2009 / Printed in Germany / Subject to modification
