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Varec Biogas

Varec (VApor RECovery Specialty Company) began business in the 1930's at its manufacturing plant in Compton, California. Varec was there in the infancy stage of the biogas market in the early 1950's. From the onset, Varec's focus was to deliver Biogas Handling products that suited customers' specific requirements, even if it meant creating the product off the drawing board. Varec initially sold direct to end-users and in the 1970's instituted a Sales Representative Network that catered to Municipal Wastewater Treatment Plants. A select number of Sales Representatives in the United States helped Varec acquire approximately 90% installed base from the 2,500 Wastewater Treatment Plants that utilize Anaerobic Digesters for Biosolids Treatment built between the mid-60's to late 70's. Today, Varec Biogas is 100% dedicated in providing total solutions to the biogas market. In February, 2003, Westech Industrial Inc. acquired the biogas portion of the Varec business from Tyco Valves and Controls, LP Inc.

Flame Arrester

Varec Biogas 5000 / 5010 Flame Arrester


Varec 5000/5010 Series Flame Arresters are specifically designed for the wet, dirty gas normally encountered in biogas plants. The unique unitized housing design allows for removal and replacement of the element without changing pipe stresses. The individual sheets of the element can be easily cleaned, thus allowing quick maintenance and minimal downtime. For use alone on vent or compressor lines, in conjunction with a thermal shut-off valve for boilers or waste gas flares, or with a 2010B/2020B relief valve for safe venting of digesters.



  • Extended Bank Assembly
  • Three to Four Times Net Free Area through Bank
  • UL Approval
  • Heavy Wall Cast Housing in 356HT Aluminum
  • Removeable Cover Plate
  • Vertical or Horizontal


Varec Biogas 5810B / 5820B Flame Arrester


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 incorporated added features that reduce potential malfunctions from these extreme conditions. The 582OB 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.



  • Vent to Atmosphere or Pipe-away option
  • Oversized Pressure and Vacuum Ports for maximized flow capacities
  • Extensible Flame Arrestor Bank Assembly
  • Replaceable and Interchangeable Pressure and Vacuum Seat Rings
  • Optional “All Weather” Coating of Valve Seats and Guides