In power generation plants, large ball, gate or butterfly process valves control the flow of steam, oil, water, or gas. Because of the massive amount of power required and the intrinsic risks within, hydraulic systems and power units designed for operation in non-classified or hazardous classified areas, are used to maximize power generation efficiency and reliability.
Solutions that include the use of digital directional servo proportional valves, safety valves, servo pumps or variable displacement piston pumps maximize electrical efficiency, either with HLP mineral oils, synthetic fluids or phosphoric-based flame-resistant fluids.
Atos provides innovative and safe electrohydraulic systems to control process actuators and valves, of steam, gas or hydro turbines. Customized solutions include the use of digital directional servo proportional valves, safety valves, servo pumps or variable displacement piston pumps to maximize electrical efficiency, either with HLP mineral oils, synthetic fluids or phosphoric-based flame-resistant fluids.
There are two types of process valves: open/close or regulating. The former can be handled by on-off solenoid valves, while the latter are controlled through servo-proportional valves or axis control systems, which regulate their opening and holding in position, according to the exact power consumption the system requires. Precise position control lets the system work inside the operative range where the maximum point of electrical efficiency is reached, boosting the entire energy production process. In both cases, Atos offers a range of industrial or explosion-proof electrohydraulic components.
High performance hydraulic components from Atos
Based on their role within the system and potential hazard they could generate in a sudden stop, process valves are classified according to the desired reaction in case of unexpected event, resulting in emergency status:
- Fail closed, where the valve closes completely
- Fail open, where the valve fully opens
- Fail last, where the valve maintains the last actuated position
Using power units and hydraulic safety systems with redundant architecture gives process systems options in case of power supply breakdown. Such custom options could include power supply voltages for solenoid valves, for applications powered through mains power supply and with backup battery packs.
Additionally, hydraulic systems for turbine control consist of an HPU that generates the hydraulic power required for the movements of individual actuators. The presence of dual or triple redundant subsystems maximizes system safety and maintenance while keeping the turbine in full operation, without having to shut it down, even in case of failure of some crucial components for proper operation.
HPU for geothermal steam turbine
Variable displacement piston pumps or, increasingly, servo pumps equipped with brushless motors, deliver hydraulic power only when requested with the exact amount of flow rate needed to feed the power generation system, optimizing energy consumption and classifying hydraulic power packs as environmentally friendly units.
Often due to the high working temperatures at which steam turbines operate, or due to placement within classified areas for gas turbines, hydraulic control systems require special fire-resistant synthetic or phosphoric-based hydraulic fluids. Atos electrohydraulic systems are equipped with FKM seals that are suitable with these types of fluids, or even with EPDM compounds when using avionic fluids. At the same time, some types of turbines are designed to operate in very cold environments, where seals with special compounds and stainless steel components are used, which can operate down to –60°C.
The wide industrial, ex-proof and stainless-steel products portfolio, which includes servo pumps, variable displacement pumps, safety valves, servo proportional valves, servo cylinders with built-in transducers, axis & p/Q controls, forms the bedrock of the Atos electrohydraulics systems engineering.
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Filed Under: Components, Safety, Valves & Manifolds
