Where are poppet valves installed in a vapor recovery system?

Poppet valves are crucial components in vapor recovery systems, primarily installed on the vapor recovery riser. This placement is essential because the vapor recovery riser is responsible for transporting vapors from the storage tank to the recovery system when fuel is dispensed.

By positioning poppet valves in this location, the system can effectively prevent the escape of fuel vapors into the atmosphere during the transfer of liquid fuel. The valves operate by opening to allow vapors to flow when needed and closing to contain the vapors, ensuring environmental compliance and enhancing safety by minimizing the risk of vapor release.

This functionality is essential as it helps maintain the efficiency of the vapor recovery process, preventing harmful emissions and facilitating the recovery of vapors that can be returned to the storage tank. In contrast, the other options do not align with the primary purpose and operation of poppet valves within the vapor recovery context.