Protecting pressurised systems from catastrophic overpressure events requires pressure relief valves that deliver unwavering reliability whilst maintaining tight shutoff capabilities close to set pressures. Anderson Greenwood relief valves represent the industry benchmark for overpressure protection, offering advanced pilot operated and direct spring designs proven across more than 50 years of demanding service. These premium performance devices maximise operating pressures whilst minimising product loss and emissions through innovative engineering that addresses the most severe process conditions.
Understanding what distinguishes Anderson Greenwood valves enables engineers and facility managers to specify optimal overpressure protection for critical applications. Natradesource provides industrial solutions incorporating proven technologies for demanding operational environments. Whether protecting cryogenic storage tanks, managing high pressure gas systems, or controlling steam service applications, Anderson Greenwood relief valves deliver the precision, durability, and code compliant performance modern industrial operations demand.
Anderson Greenwood pilot operated relief valves deliver superior capabilities compared to conventional direct spring designs through sophisticated control mechanisms that provide exceptional seat tightness, balanced operation, and modulating action. These technological advantages translate directly to improved process efficiency and reduced operating costs.
The pilot operated design maintains valve seat tightness to 95 or 98 percent of set pressure depending on series configuration, dramatically exceeding the 90 percent capability typical of direct spring valves. This enhanced tightness allows facilities to operate systems at higher pressures closer to relief valve set points, maximising process output and efficiency. The higher the system pressure approaches the pilot operated valve set point, the greater the downward seating force becomes, exactly opposite to direct spring valves where spring compression weakens as pressure increases.
Soft seat designs incorporating PTFE or elastomer materials provide repeatable bubble tight performance before and after each relief cycle, eliminating expensive metal seat lapping requirements. The Series 400 modulating pilot operated valve delivers main valve seat tightness to 98 percent of set pressure without leakage, whilst the Series 800 high pressure version maintains this performance up to 6,170 psig. Fisher process control equipment complements Anderson Greenwood valves in integrated safety systems.
Anderson Greenwood pilot operated valves utilise balanced designs ensuring proper operation and lift unaffected by back pressure, eliminating costly and fragile metal bellows required for conventional valves in high back pressure service. The balanced configuration proves particularly valuable in applications where discharge piping creates significant back pressure that would otherwise compromise direct spring valve performance.
The unique field test capability allows accurate set pressure verification with valves remaining in service, eliminating requirements for system isolation block valves. This feature enables periodic testing confirming proper set pressure without process shutdown, supporting predictive maintenance strategies whilst ensuring continuous overpressure protection. Operators simply connect test equipment to the field test port and verify set pressure matches specifications, completing testing within minutes rather than hours required for valve removal and bench testing.
Anderson Greenwood offers extensive valve series addressing applications from basic to the most severe service conditions. Understanding differences between series enables proper selection matching specific operational requirements and process characteristics.
The Series 200 pilot operated relief valve provides economical overpressure protection for standard gas, vapour, and liquid applications requiring reliable performance without premium features. This workhorse design suits general industrial processes where basic pilot operated capability suffices. Series 400 valves represent the most popular configuration, featuring modulating action that minimises product loss during relief events whilst reducing noise during normal system upsets. The high gain modulating action provides full main valve lift by five percent overpressure, significantly better than the ten percent typical of other designs.
Series 500 valves incorporate all plastic seats and seals providing chemical compatibility with aggressive media including hot water, steam, and corrosive liquids. The PTFE piston seat design remains totally captive, eliminating seat extrusion problems at elevated temperatures. Temperature capabilities range from minus 65 to plus 515 degrees Fahrenheit, with optional construction extending service to minus 320 degrees Fahrenheit for cryogenic applications. These valves specifically target applications where metal components would suffer corrosion damage, such as boiler feedwater service.
Series 700 pilot operated valves feature pop action capability providing instantaneous full opening at set pressure without main valve throttling, preventing freeze ups in cryogenic or refrigerant services where gradual opening allows ice formation. The snap action proves essential in applications demanding immediate full capacity relief. Series 800 valves extend pilot operated technology to high pressure applications ranging from 1,481 to 6,170 psig, handling gas, liquid, and mixed phase services including dirty applications.
The Safety Selector Valve system enables safe switching from active pressure relief devices to standby units whilst maintaining continuous overpressure protection. This innovative design requires only one minimally sized vessel penetration and provides less than three percent pressure drop to the active valve inlet, dramatically outperforming traditional dual relief systems using bulky piping fabrications or three way block valves. The tandem configuration simultaneously switches inlet and outlet selector valves through foolproof interlocking mechanisms, eliminating operator errors that could leave systems unprotected.
Anderson Greenwood relief valves deliver measurable operational benefits that justify their position as preferred overpressure protection across petroleum, chemical, power generation, and manufacturing sectors. These advantages extend beyond initial performance to encompass lifecycle cost reductions and enhanced safety.
Soft seat designs combined with modulating action minimise product venting during relief events, reducing both financial losses from wasted inventory and environmental emissions requiring regulatory reporting. The precise modulating control opens valves just enough to prevent overpressure rather than snapping fully open unnecessarily. This measured response proves particularly valuable in applications handling expensive or hazardous materials where minimising release quantities affects both operating economics and environmental compliance.
The bubble tight seating before and after relief cycles prevents chronic weeping losses that plague metal seated conventional valves. Even minimal leakage represents significant product waste over extended periods, whilst fugitive emissions contribute to environmental non compliance issues. Anderson Greenwood seat technology addresses both concerns through proven designs maintaining seal integrity through hundreds of thousands of operating cycles.
Replaceable soft seats and seals enable easy, quick renewal without expensive time consuming metal seat lapping procedures typical of conventional valves. Maintenance personnel complete seal replacement in fraction of the time required for precision lapping, returning valves to service faster whilst reducing labour costs. The rugged bracket pilot mounting protects against vibration and careless handling, common sources of damage during transportation and installation.
Single set pressure adjustment proves accurate and dependable, simplifying calibration procedures compared to complex multi step processes required by some competing designs. The straightforward adjustment enables precise setting even under field conditions where sophisticated calibration equipment may prove unavailable. Anderson Greenwood valves suitable for dirty or wet service incorporate non flowing pilots minimising entrance of contaminants and preventing hydrate formation that disables sensitive components. Low velocities ensure particles drop out upstream of pilot inlet screens, enhancing reliability in challenging applications.
Proper Anderson Greenwood valve selection requires evaluating multiple application factors whilst ensuring compliance with relevant codes and standards. The extensive product range accommodates virtually any industrial overpressure protection requirement through appropriate series and configuration choices.
Begin selection by characterising the process fluid as gas, vapour, liquid, steam, or mixed phase, as this fundamentally determines suitable valve series. Identify required set pressure, expected relieving pressure accounting for allowable overpressure, back pressure conditions, and operating temperature range. Calculate required relieving capacity using recognised methods such as API 520 or applicable code provisions, then size orifices accordingly.
Compare selected valve type and orifice against pressure temperature rating tables ensuring compatibility with process requirements. Verify proper material selection accounting for chemical compatibility, with particular attention to soft goods exposed to process media. Evaluate whether modulating or pop action opening better suits the application, considering factors including freeze up risks, noise concerns, and product loss implications.
Anderson Greenwood pilot operated relief valves carry ASME Section VIII and Section XIII Code Stamps for gas, liquid, and steam service, plus CE marking to European PED directive requirements. DOT compliance per 49CFR192.199 and CSA Z662 certification enable installations on natural gas pipelines and distribution systems. API 526 dimensional compliance available for Series 200, 400, 500, and 800 pilots eliminates piping modifications during upgrades, simplifying retrofits and replacements.
The comprehensive certifications reflect rigorous design, manufacturing, and testing protocols ensuring valves meet stringent safety and performance standards. Third party certification provides independent verification of capabilities, supporting regulatory approval processes and insurance requirements. Full nozzle main valve options further expand API 526 compliance for applications demanding standard dimensions.
Anderson Greenwood relief valves represent the premium choice for industrial overpressure protection, delivering advanced pilot operated technology, superior seat tightness, and proven reliability across more than 50 years of service. The comprehensive series range accommodates applications from basic general service through the most severe conditions involving aggressive chemicals, extreme temperatures, and high pressures. Advantages including enhanced operating efficiency through tightness to 98 percent of set pressure, reduced product loss via modulating action, and simplified maintenance through replaceable soft seats translate to measurable operational and economic benefits.
Proper series selection accounting for process characteristics, environmental conditions, and code compliance requirements ensures optimal performance whilst meeting regulatory obligations. The extensive certifications including ASME, API, CE, DOT, and CSA reflect rigorous engineering and testing supporting safety critical installations. Whether protecting refinery processes, chemical reactors, power generation systems, or cryogenic storage, Anderson Greenwood relief valves provide the precision control and dependable overpressure protection modern industrial operations demand.
For expert guidance on selecting Anderson Greenwood relief valves suited to your specific application requirements and operational environment, contact the specialists at Natradesource who provide comprehensive valve solutions backed by extensive industry experience and technical expertise.
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