The document describes the Voith I/H Converter, specifically types DSG-B03212 and DSG-B07212, providing an installation and operating manual.
Function Description
The I/H converter is an electro-hydraulic, remote-controllable current-to-pressure converter. Its primary function is to convert an electric set signal (e.g., 4-20 mA) into a corresponding hydraulic output pressure, which is reduced from the supply pressure. This capability allows for remote-controlled, infinitely variable adjustment of control pistons on hydraulic cylinders, such as those positioning steam turbine valves. The device ensures quick and hysteresis-free pressure setting.
All necessary electrical components for the I/H converter's operation are integrated within the unit and protected against environmental influences. The Voith control magnet (VRM) houses controllers for setpoint limitation and magnetic force control. Potentiometers X0 and X1, accessible from the outside, allow for the allocation of output pressure PA to the setpoint w.
A key feature is the manual operation knob on the control magnet. This knob can be used to define a spring force, adjustable via the knob, which controls the piston through the magnet armature and tappet. The hydraulic force FHyd, proportional to the output pressure PA, acts against this spring force. This enables adjustment of the output pressure even without an electrical connection.
The control system operates by an electric signal w (4-20 mA) for the power setpoint UMag. A Hall probe measures the actual value in the magnetic system and returns it as UHall to the magnetic force controller. The magnetic force FMag, assigned to the setpoint w via potentiometers X0 and X1, is transmitted to the control piston by a tappet. The hydraulic force FHyd, proportional to the output pressure PA, counteracts the magnetic force. In a balanced state, the control piston is centered, and the output pressure PA matches the setpoint w. A spring force FFed generates a force offset to ensure I/H converter function even at output pressures near 0 bar.
The device also incorporates a maximum value limitation. In cases of incorrect setpoint connection (e.g., 24 VDC to the plus-port of the setpoint input), an integrated overload protector in the VRM limits the setpoint current to an uncritical value, safeguarding the I/H converter control from damage.
Important Technical Specifications
General Data:
- I/H Converter Types: DSG-B03212, DSG-B07212
- Article Numbers: 9 186827 0 (DSG-B03212), 9 186826 0 (DSG-B07212)
- Instruction Manual No.: 918 3626018861
- CE Marking: CE II 2G IIC T4
- Protection: IP 65 as per EN 60529
- Ambient Temperature (Operation): -30 ... +60 °C
- Ambient Temperature (Storage): -40 ... +90 °C
- Installation Conditions: Indoor installation, Outdoor installation, Offshore, Industrial atmosphere.
- Weight: Approximately 12 kg
Hydraulic Data:
- Supply Pressure P max.: 40 bar
- Supply Pressure P min.: PA max + 1.5 bar
- Pressure Adjusting Range PA (Output Pressure): See Chapter 6.2.1
- Flow Rate PA at ΔP = 1 bar: 17 l/min (DSG-B03212), 18 l/min (DSG-B07212)
- Return Pressure on T1 and T2: 0 bar
- Leakage at T1 (Toil = 50 °C and P=10 bar): < 4 l/min
- Leakage at T2: < 1 l/min
- Operating Medium Type: Hydraulic oil as per DIN 51524, Turbine oil as per DIN 51515, High-flash point fluid (according to customer specification)
- Oil Temperature during Operation: +10 ... +60 °C
- Cleanliness Grade (ISO VG 4406): -/19/16
- Viscosity (DIN 51519): ISO VG 32 ... ISO VG 46
- Sealing Material: FPM (Fluor-caoutchouc), NBR (Acrylnitril-Butadien-caoutchouc), or Special design.
Electrical Data:
- Supply Voltage: 24 V DC (+10% / -15%)
- Current Consumption: Approx. 0.7 A, max. 3 A for t < 1 sec
- Setpoint
w for Pressure Adjusting Range PA min....PA max: 0/4 ... 20 mA
- Input Load: 25 Ω
- Input Configuration: E360 Electronics (Applied, related to GND), E503 Electronics (Isolated (500 kΩ))
- Setpoint Limitation:
w > 35 mA (E360 Electronics), w > 90 mA (E503 Electronics)
- Adjustment Ranges X0 and X1: See Chapter 6.2.1
- Magnetic Force Switch-off at (only with E503 electronics):
w < 3 mA
- Voith Control Magnet (VRM) Marking: Ex II 2G Ex db IIC T4
- VRM Protection: IP 65 as per EN 60529
- VRM Ambient Temperature TA at T4: -30 ... +60 °C
- VRM Cable Entry (cable end design): Ex II 2G Ex db IIC T4-T6
Pressure Adjusting Range (PA):
- DSG-B03212: 0..3 bar (overall), approx. 1..3 bar (PA max at
w = 20 mA), approx. 0..0.8 bar (PA min at w = 4 mA)
- DSG-B07212: 1..7 bar (overall), approx. 5..7 bar (PA max at
w = 20 mA), approx. 1..3 bar (PA min at w = 4 mA)
Usage Features
Installation:
- Installation and operation are permitted only under the conditions specified in Chapter 1 (Technical Data).
- The device must not be installed in an explosive atmosphere. The hydraulic tank must not be in Zone 0, as explosive atmospheres could enter the valve via the tank during operation.
- Only qualified personnel (as per Section 2.3) are allowed to work on the I/H converter.
- Cleanliness is crucial during installation; impurities can damage the converter.
- Protective glasses must be worn during hydraulic connection.
- Pipes, flexible tubes, unions, and flanges must be selected according to the correct pressure stage.
- The I/H converter should be mounted in the permissible installation position (vertical, hydraulic component on top, control magnet on bottom).
- Recommended fastening bolts: 2 M10 hex. screws, property class 8.8 with washer, tightened to 35 Nm (oil-moistened thread).
- Hydraulic connections use O-rings for sealing; the customer's connecting surface must meet Ra ≤ 1.6 µm and Rmax ≤ 6.3 µm.
- External pressure variations must not affect tank return line T2 for proper functioning. T1 and T2 can be joined if the pipe to the tank is descending and has a nominal width ≥ 20 mm.
- Pipes must be cleaned and flushed carefully before installing the I/H converter. A flushing plate and an adapter for piping connection are available as accessories.
- Electrical connections must be performed by a certified electrician with explosion protection expertise. Signal and supply lines must be screened and laid separately. Poor connections can lead to unreliable operation.
Commissioning:
- The I/H converter is tested and adjusted at the factory, with settings documented in a test report. Potentiometers X0 and X1 are protected by a cap.
- All hydraulic and electric supply system connections must be checked before commissioning.
- Test Run: Ensure pipes and the hydraulic system are clean, meeting the cleanliness grade specified in Chapter 1. Operation with contaminated medium is prohibited.
- De-aeration: During the test run, air pockets may cause temporary pressure variations. To de-aerate:
- Switch on power and oil supply, check supply pressure P.
- Set setpoint
w = 0 mA.
- After 5 minutes, switch on setpoint
w = 4 mA.
- Operate the converter for at least 10 minutes at a setpoint sine rhythm (4 mA to 20 mA) or via a ramp. If not possible, connect
w = 20 mA directly.
- Check for leaks during the test run; remedy immediately if found.
- Parameter Setting: Potentiometers X0 (for PAmin at
w = 0/4 mA) and X1 (for PAmax at w = 20 mA) allow adjustment. X1 should be set before X0. Document all adjustments.
Operation:
- Manual Operation Knob: Allows operation without electrical auxiliary power. Uncontrolled stroke movements may occur due to increased output pressure.
- Remove the retaining clip.
- Turn the knob clockwise to increase output pressure PA (max. equals input pressure P).
- After use, turn the knob counter-clockwise to its end position and lock with the circlip.
- Normal Operation: The converter operates with an external setpoint. Troubleshooting is required if it does not function as expected.
Troubleshooting:
- Pressure variations:
- Supply pressure too low: Check supply pressure.
- Air pockets: De-aerate the system as described in commissioning.
- Impurities in hydraulic component: Clean inner parts or consult J.M. Voith.
- Pressure variations in tank return line T2: Ensure T2 is not affected by other consumers; consult J.M. Voith if needed.
- Output pressure does not follow setpoint
w (PA = 0 bar or PA=P):
- Blocking of control piston: Clean inner parts or consult J.M. Voith.
- Defect in control magnet VRM: If the control piston moves and output pressure adjusts with the manual knob, the VRM is defective; replace the I/H converter.
Maintenance Features
Maintenance, Servicing, and Inspections:
- All maintenance, servicing, and inspection work must be performed in a non-hazardous atmosphere.
- Regular inspections are necessary for trouble-free and reliable operation. Intervals may need to be shortened for continuous operation in extreme ranges.
- Combustible dusts must be removed immediately to prevent fire/explosion.
- Inspection works can be performed by the operator's expert personnel (meeting Chapter 2.3 criteria).
Maintenance Intervals and Work:
- Routine Inspection:
- Check pipes, unions, and connections for leaks, impurities, and damage. Remedy as needed.
- Monitor operating behavior for changes (e.g., noise); analyze and eliminate causes.
- After approx. 740 operating hours or 1x per month:
- Take an oil sample from the tank; check for solid/suspended matters, water content, color change, air bubbles, and cleanliness.
- Check and change oil as required.
- After approx. 8000 operating hours or 1x per year:
- Take an oil sample from the tank and analyze it chemically.
- Check and change oil as required.
- Check and retighten electrical connections.
- After 60,000 operating hours or 7 years after first commissioning (latest):
- Remove the I/H converter, disassemble in an appropriate workshop. Inspect inner parts, replace conspicuous parts and all seals.
- Perform a test run on a suitable test stand; check and document operational behavior.
- These inspections must only be performed by the operator's trained expert personnel in an appropriate workshop or by Voith personnel at the Voith workshop.
- After another 60,000 operating hours or 7 years after the last inspection (latest):
- Remove the I/H converter, have it inspected and completely overhauled at J.M. Voith SE & Co. KG. All conspicuous parts will be replaced.
- Perform a test run to check and document operational behavior.
- Only J.M. Voith SE & Co. KG expert personnel are allowed to perform these inspections.
Spare Parts Information:
- Only original Voith parts are allowed.
- Refer to the spare parts catalog of the outline drawing (Chapter 10) for deliverable parts. Contact J.M. Voith for unlisted parts.
- Spare parts must be stored protected against corrosion, in a dry, dust-free area. Remove corrosion protection before installation.
- Elastomer seals must not be stored with chemicals, solvents, fuels, or acids. They need to be packed airtight and protected from UV light.
- Storage time for elastomer seals: max. 6 years (NBR) and 10 years (FPM).
Decommissioning:
- Ensure no explosive atmosphere is present during decommissioning.
- If switched off for repair, inspection, or system shutdown, switch off the oil supply and release pressure accumulators.
- Wear protective glasses when disassembling hydraulic connections.
- Disconnect 24 V DC power supply and remove lines and piping. Collect any leaking oil in a suitable container and dispose of it properly. Close all openings, clean, and pack the I/H converter.
- Disposal: Observe local provisions for environmental protection. The I/H converter contains steel, copper, synthetic materials, electronic components, and residual oil.
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