Key Benefits and Advantages
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Throttling Type Relief: The valve opens gradually as pressure exceeds the setpoint, providing a smooth relief action that minimizes the risk of damaging pressure surges in the downstream system.
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High Flow Rates: Despite their compact size, these valves are engineered to handle significant flow capacities, ensuring they can vent enough volume to keep the system safe during an overpressure event.
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Superior Low-Pressure Sensitivity: Featuring a large diaphragm area, the 289 Series offers exceptional sensitivity and accuracy for very low-pressure settings, where smaller valves might struggle to respond.
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Reliability Through Simplicity: With a straightforward spring-loaded design and minimal moving parts, the 289 Series provides consistent performance with high reliability and low maintenance requirements.
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Compact Design: The small physical footprint allows for easy installation in tight piping galleries, regulator pits, or on skid-mounted equipment.
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System Protection: Acts as a dependable watchdog for downstream regulators, ensuring that a regulator failure or external surge does not result in hazardous overpressure conditions.
Technical Properties
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Body Sizes: Available in multiple sizes, commonly ranging from 3/4 inch to 2 inches (DN 20 to 50).
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End Connections: Offered in NPT threaded configurations for easy integration into standard piping.
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Pressure Settings: Designed specifically for low-pressure relief, often ranging from inches of water column up to several psi.
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Material Construction: Typically features a durable aluminum body with various elastomer options for the diaphragm and seat to ensure compatibility with natural gas, air, and propane.
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Non-ASME Designation: These are pressure control relief valves intended for process stabilization; they are not intended for use as ASME-coded safety relief valves.
Field of Application
The 289 Series is primarily used in low-pressure gas systems to prevent downstream equipment from being exposed to higher-than-normal pressures. It is a staple in municipal gas distribution and commercial heating systems.
Primary Industries and Uses:
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Natural Gas Distribution: District and residential regulator stations as secondary overpressure protection.
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Industrial Fuel Gas: Protecting burners, furnaces, and ovens from pressure spikes in the fuel line.
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Commercial Establishments: Relief for gas systems in schools, hospitals, and shopping centers.
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Tank Blanketing: Used as a simple relief or vent valve for low-pressure storage tanks.




