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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.

Thermal Valve

Varec Biogas 430 Thermal Valve

The Varec 430 series Thermal Operated Shutoff Valve is designed to protect low pressure waste gas systems by shutting off the gas flow if a fire is burning in the piping. Once gas is no longer supplied at the source of combustion, the fire is extinguished. The 430 Series Thermal Valve is typically installed in lines leading to boilers, blowers, compressors, or other possible sources of combustion. The valve may be installed in either horizontal or vertical piping and is suitable for working pressures up to 5 psig (34.5 kPa). For higher pressure ratings, consult factory. For maximum protection from flame fronts caused by flashbacks in the waste gas piping, a Varec Model 5010 Flame Arrester is recommended in addition to the thermal valve. This combination unit is specified as Model 450 Flame Trap Assembly and is described in detail in Bulletin PDS 450kWT.

The Model 430 Valve is a fusible element released, spring operated pallet type shut-off valve. During normal operation, the pallet is positioned above the valve seat. The pallet is connected to a rod which sits atop a fusible element. In this position , the valve is open, permitting a constant flow of gas through the piping system. Should the valve be subjected to flashback temperatures, the fusible element in the valve will melt within 15 seconds upon reaching 260º F (127º C) for valves, sizes 2″-4″ and within 22-45 seconds for valves, sizes 6″-12″. The valve compression spring immediately forces the pallet down against the valve seat, closing the valve, thereby shutting off the gas flow. The thermal valve is designed for ease of operation and maintenance. A sight glass is located beneath the winged inspection cap and an indicator rod is connected to the pallet. The pallet position may be determined simply by viewing the indicator rod through the sight glass, without having to remove the valve from service. This allows the operator to quickly determine whether the valve is open or closed without having to use a manometer or pressure gauge when trying to locate a line blockage. The gas tight fuse plug allows the fusible element to easily be replaced without having to remove the valve cover or disassemble the valve.



  • Fusible element and spring provide quick shut-off
  • Sight glass with indicator rod
  • Gas tight fuse plug allows replacement without dissembling valve