Way Valve Module WSM
Way Valve Module, Redundant Way Valve, Redundant Proportional Directional Control Valve
Voith way valve modules are redundant proportional directional control valves. They have integrated position controls and provide direct control of hydraulic positioning cylinders in processes requiring high availability. The positioning cylinders operate a valve that controls the mass flow needed to drive machinery. Voith way valves ensure very precise and highly dynamic control of the mass flow.
A way valve module consists of two way valves connected in parallel. Working in conjunction with a hydraulic cylinder, the way valve converts a constant input pressure into a variable stroke. A standard 4 – 20 mA signal specifies the stroke of the positioning cylinder. The major components of the way valves are a 3/3 way hydraulic unit for single-acting positioning cylinders and a force-controlled electromagnet with integrated position control. An additional pilot valve is not needed with the Voith electrohydraulic way valve module.
Every way valve has a monitoring circuit that detects malfunction of a way valve. In the event of way valve malfunction, a hydraulic maximum selection circuitry ensures that the other way valve assumes control. This makes it possible to remedy the cause of the malfunction during operation.
The Mean Time Between Failures (MTBF) for Voith way valve modules is over 8,800 years. Your equipment runs for a very long period of time without unplanned downtime; availability is increased.
Voith Digital Solutions GmbH
Actuators and Governors
74564 Crailsheim, Germany
Tel. +49 7951 32-470
Fax +49 7951 32-605
|Flow rate||Up to 700 l/min [182 gpm] at 4 bar [58 psi] differential pressure|
|Input pressure||Up to 40 bar [580 psi]|
|MTBF (Mean Time Between Failures)||8,800 years (calculated in accordance to MIL‑HDBK‑217, Siemens SN 29500 and taking into account diagnostic capability and reparability during operation at the actual redundancy)|
|Supply voltage||24 VDC|
|Current consumption||2.0 A (6.0 A for t < 1 s)|
|Input signal||4 – 20 mA|
|Fail-safe operation||Internal return spring in each way valve|
|Ambient temperature||-20 to +80°C [-4 to 176°F] (standard version, not rated for
use in potentially explosive areas)
|Explosion proof rating (optional)||
|Protection class||IP 65|
|Safety integrity level||SIL 2 (on request)|
Advantages and benefits
- Thanks to the redundancy provided by two way valves, the Mean Time Between Failures (MTBF) for the way valve module is over 8,800 years. Your equipment operates with maximum availability. Productivity increases and the costs associated with lost production remain low.
- It is possible to replace a faulty way valve during operation. You avoid unplanned downtime and their associated high costs.
- Voith way valve modules are not sensitive to contaminated pilot oil. Turbine lubricating oil is suitable as the operating fluid. One oil supply system for both lubricating and pilot oil suffices. Maintenance is simple, which helps you lower operating costs.
- During load rejection, the way valve shifts the control valve to the partial-load position very rapidly (approx. 300 ms). When a shutdown command is received, the way valve shifts the control valve to the safe position (open or closed) very rapidly (approx. 300 ms). This ensures high availability of your equipment.
- The way valve incorporates fast and exact position control. Very good control response, almost no hysteresis and a resolution better than 0.1% ensure very fast and accurate control. You benefit from having a stable process with high product quality.
- Connections are industry-standard. The way valve module mounts to your equipment easily. This reduces the costs for integration.
- The stroke and positioning speed can be adjusted easily on-site by means of a potentiometers. This allows you to adjust the stroke to the application quickly and without any delays.
- For use in hazardous areas, we offer explosion proof way valve modules with the required certificates.
Typical fields of use
- Operation of the control valve of
- steam turbines
- gas turbines
- Retrofit of mechanic-hydraulic valve controls
- Upgrade of systems with Voith DSG I/H converters, WSR way valves or T‑WSR tandem way valves
- Upgrade of systems with Woodward current-to-pressure converters CPC, CPC-II or CPC-DX
The way valve module employs a two-channel design. A redundant control system provides the two setpoints w1 and w2 in the form of a standard 4 – 20 mA signal for the two way valves.
The control gain setting is the same for both valves. The output pressures pA1 and pA2 or the corresponding volume flows are directed to the "Max. Module", the A port of which is connected to the single-acting cylinder. If one of the two way valves fails, the associated force exerted by the magnetic force FMag and the output pressure drop to zero. The resulting connection of the A port in the way valve to the tank return line T causes the ball in the "Max. Module" to block the output of the failed way valve automatically. The pressure gauge and pressure transmitter on the associated way valve module display 0 bar. The functional way valve assumes control automatically and keeps the equipment operating. It is possible to replace the faulty way valve during operation.