Fisher 298 Gas Relief Valve: Ensuring Safety in Gas Systems

The Fisher 298 Gas Relief Valve is a crucial safety – related device in gas systems, designed to safeguard the integrity and safety of the overall gas distribution and utilization infrastructure.​
Design and Structure​
Valve Body Material: The valve body is commonly crafted from high – strength cast iron or steel. Cast iron, with its lower cost and good casting properties, meets general working condition requirements. Steel, on the other hand, offers higher strength and toughness, making it suitable for harsher or high – pressure environments. It can effectively resist the corrosion of gas and pressure impacts, ensuring the structural integrity of the valve body during long – term use.​
Internal Components: It is equipped with high – precision diaphragms and valve discs inside. The diaphragm is extremely sensitive to pressure changes. When the system pressure rises, the diaphragm deforms due to the applied force. The valve disc is linked to the diaphragm and opens or closes under the drive of the diaphragm, enabling the discharge and cutoff of gas. The manufacturing process of these components is sophisticated, guaranteeing the sensitivity and reliability of the relief valve.​
Working Principle​
Under normal operating conditions, gas flows within the set pressure range. At this time, the Fisher 298 Gas Relief Valve remains closed, with the valve disc closely fitting the valve seat to prevent gas leakage. When the pressure in the gas system rises due to various reasons (such as equipment failure, sudden changes in flow rate, etc.) and exceeds the pre – set relief pressure value, the pressure acts on the diaphragm, causing the diaphragm to displace upward. The displacement of the diaphragm drives the valve disc to leave the valve seat, allowing gas to be discharged from the relief port, thereby reducing the system pressure. When the system pressure drops back to the normal range, the diaphragm returns to its original position under the combined action of its own elasticity and the system pressure, and the valve disc closes again, and the relief valve stops working.