The Varec 5810B/5820B Series Relief Valve and Flame Arrester is a combination of the Varec 2010B/2020B Series Pressure and Vacuum Relief Valve and the Varec 5000 Series Flame Arrester. This unit combines the high flow capacity of the Relief Valve with the easy-to-maintain extensible bank flame arrester for maximum protection and reliable operation.
The 5810B/5820B Series Pressure and Vacuum Relief Valve with Flame Arrester are installed on anaerobic digester covers or low-pressure gas holder roofs. The relief valve protects the cover from excessive pressure and vacuum within the tank. It maintains system operating pressure so waste gas is not routinely vented to the atmosphere. The flame arrester protects the tank from accidental ignition of sludge gas within the digester or gas holder. It is designed to stop the propagation of flame from external sources. For further information on these devices, see the product data sheet for 2010B/2020B, and 5000/5010. A variety of materials are available to suit climate conditions. The standard aluminum construction is suitable for moderate climates. In extreme hot, humid or freezing weather, the "All- Weather" 5811B Series is recommended. This design incorporates added features that reduce potential malfunctions from these extreme conditions. The 5820B Series provides for further protection from cold climates. This unit incorporates an enclosed pressure port on the relief valve. This allows gas to be vented away from the valve. It is especially suited for field installation of insulation jackets or insulated shelters. The 5821B Series includes the pipe-away outlet and the "All- weather" features for maximum cold weather protection. If H2S Corrosion is a concern, supplying the relief valve with 316 SS trim is an option. The flame arrester bank sheets are also available in 316SS material.
Whenever the system gas pressure or vacuum exceeds the setting, the pallet lifts. Only excess pressure is vented to the atmosphere. Air is drawn into the digester only to relieve an excess vacuum condition. The valve remains closed when the gas utilization system remains within normal operating pressure. The valve pallets are deadweight loaded with a field adjustable pressure setting range. Side and center pallet guides are incorporated for stability. "Air cushion" Teflon seat inserts ensure a tighter seal. Removable seats can be easily replaced. The case outlet adapter on the pipe-away model is one pipe size larger than the valve inlet flange to optimize flow capacities. The "All-weather" models feature a special non-frosting and icing-resistant coating.