Severe Service Control Valves
The Fisher range of severe service control valves optimize process performance in any application.
The Fisher range of severe service control valves optimize process performance in any application.
Severe service control valves are used in the most difficult installations within your process plant. These installations commonly include cavitating, erosive, corrosive, noisy, high pressure, high temperature, high pressure drop, or high velocity media. To maximize longevity in these harsh conditions, severe service control valves typically utilize extremely hard materials, materials that withstand temperature and pressure extremes, bodies with special flow paths, bodies with high capacities, and cages with unique flow passages. A severe service valve may or may not be a critical service valve—one that’s essential to the operation of the plant.
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This webinar is an in depth presentation on control valve noise and the technology used to mitigate the different types of noise that can occur. Fisher control valves combined with proper noise abatement trim provide the neccessary solutions to control harmful noise issues.
Learn about outgassing applications and why specialized control valve sizing and selection practices are needed to ensure capacity needs, vibration risk, and erosion concerns are addressed. This webinar also discusses various Fisher valve and trim offerings and customer successes.
Across various industries, materials other than steel, alloy steel, and stainless steel are often necessary to meet the needs of critical corrosive applications. This webinar covers the basics of these “Exotic Alloys”, the benefits they provide, the challenges they create, and how to specify these materials amid confusing industry designations.
This webinar is an in depth presentation on control valve noise and the technology used to mitigate the different types of noise that can occur. Fisher control valves combined with proper noise abatement trim provide the neccessary solutions to control harmful noise issues.
Learn about outgassing applications and why specialized control valve sizing and selection practices are needed to ensure capacity needs, vibration risk, and erosion concerns are addressed. This webinar also discusses various Fisher valve and trim offerings and customer successes.
Across various industries, materials other than steel, alloy steel, and stainless steel are often necessary to meet the needs of critical corrosive applications. This webinar covers the basics of these “Exotic Alloys”, the benefits they provide, the challenges they create, and how to specify these materials amid confusing industry designations.
At the end of a steam power cycle the water is condensed back to liquid form. A centrifugal pump then moves this water through heaters back toward another pass through the boiler. All centrifugal pumps have a minimum flow rate through the pump to avoid overheating and cavitation. Valve controls bypass flow from pump outlet back to some lower pressure point, this bypass flow prevents overheating and cavitation. The valve must be selected to prevent or withstand cavitation.
Industrial steam generation and commercial electric-power boilers must be filled with water to a required level and then that level maintained during firing or heating of the boiler to generate steam. The water flow requirements prior to steam generation are controlled by a startup valve. Filling the boiler, maintaining water level during startup, and transferring load control to the main feedwater regulator are duties of the startup control valve. Initial conditions will require cavitation and fine flow control from the startup valve over a wide range of flow and pressure conditions.
Feedwater pumps impart high energy in terms of flow and pressure to the water going to a boiler. Centrifugal pumps require a minimum flow rate to maintain stable operation and avoid internal cavitation. When system conditions limit the flow rate below the pump minimum, a control valve allows bypass flow from the pump outlet back to the system upstream of the pump. The system flow rate is accomplished and the pump health is maintained. The valve itself must be selected to control pressure drops (example 6000 psid) while preventing cavitation.
Heat transfer inside a boiler is hindered by combustion products attached to the boiler surfaces. Soot blowers utilize system steam to blow those materials off the surfaces and thus maintain boiler efficiency. These valves take main steam sources and reduce the pressure while controlling flow in order to accomplish the main task without creating damaging noise and vibration.
During startup, shutdown, and emergency conditions the steam normally sent to the turbines is bypassed through these valves to condenser or atmosphere. This allows power delivery from the turbines to be curtailed and the steam recycled. The valve must provide noise reduction, high flow and pressure drop capability, while being suitable for large temperature differences.
This valve recycles flow through the primary ethane pump when needed to prevent cavitation. It is used most commonly in commissioning and startup as the unit is brought up to full capacity. Anti-cavitation trim is nearly always required due to the elevated pressure drop across the primary pump. Micro trims may be required as well to address low flow requirements.
This valve is a high pressure vent to flare header valve that is operated under emergency conditions. If the pressure in the separator increases above the set point, it's relieved to safeguard the separator. These valves are subjected to very high pressure drops, resulting in high levels of aerodynamic noise. Globe style valves with attenuating trims are commonly required to mitigate noise and potential vibration.
Water injection pumps deliver large flow rates at high pressures for enhanced oil recovery. The water is injected into the oil formation at key locations to maintain the formation pressure and drive the oil toward the production lines. Careful control of the pressure and flow is required to maintain this without damaging the water-oil interface. Valve arrangements allow the bypass to either go overboard or to a produced water reservoir. Centrifugal pumps require a minimum flow rate to maintain stable operation and avoid internal cavitation. When system conditions limit the flow rate below the pump minimum, a control valve allows bypass flow to maintain the minimum flow and prevent pump damage. The valve must handle the associated cavitation potential.
Converting raw hydrocarbon liquids into motor fuels and basic chemicals for manufacturing require many separation steps. Heat, pressure, and catalysts are used to accomplish this separation inside large vessels. Valves control the flows and pressures for these vessels. Frequently flows coming out take a pressure drop across the valve causing a further separation of liquid and gas. This separation is rapid and must be controlled by the valve. Special valve constructions accommodate compressible noise, liquid induced erosion, and potential corrosion while throttling the flow.
Amines and similar chemicals are frequently mixed with raw industrial gases to remove acid gas (H2S, CO2) as in preparing raw natural gas for use in refining processes. The amine liquid takes the acid gases into solution. A control valve lowers the pressure of the amine / acid solution and the acid gases come out of solution. This is the first step in a closed loop that regenerates the amine liquid for another round of acid gas removal.
Centrifugal compressors are dynamic machines, the gas is compressed by high-speed, rotating impellers. Slow changes in flow and pressure demand can be accomplished by changing the compressor speed. Compressor inertia prevents rapid changes of the operating flow and pressure, so a special valve controls bypass flow from the compressor outlet to the inlet providing both rapid process control and surge prevention in the compressor.
During initial operation of the HRSG, the steam is vented through sky vent valves and vent silencers. This keeps the hot steam away from the turbine bypass valves, which could develop high stress levels due to the temperature differential. Once the unit is running, the sky vent valves must provide excellent shutoff to maintain high steam utilization and production from the turbines.
