API 682 Plan 74 | Buffer Gas Control Panel for Pump Double-Ended Dry Gas Seals

The API Plan 74 buffer gas control panel supplies clean, pressurized buffer gas, typically nitrogen, to double-ended dry gas seals. It follows the API 682 Plan 74 piping arrangement and provides stable gas pressure and controlled flow.

Integrated condensation filtration: Removes particles, oil mist, and moisture to help maintain clean and dry buffer gas.
Pressure and flow control: Pressure regulation and flow limitation maintain stable buffer gas conditions. A needle valve enables precise flow adjustment.
Pressure and flow monitoring: Pressure gauges, pressure transmitters (PIT), flow meters, or flow transmitters (FIT) provide local monitoring. DCS signal output is also supported.
Valves and service interfaces: Shut-off valves, check valves, and vent/drain ports simplify startup, shutdown, maintenance, and system isolation.
Modular panel design: Centralized interfaces simplify installation and maintenance while reducing on-site piping work.
Optional configurations: Differential pressure alarms, redundant gas supply, sampling ports, fixed-point monitoring, and interlock functions are available.

The API Plan 74 buffer gas control panel is designed for pressurized, non-contact double-ended dry gas seals. It supplies clean, pressurized buffer gas, typically nitrogen, to the cavity between the two seals.

Before entering the seal cavity, the buffer gas passes through filtration, pressure stabilization, and flow control. This process creates a stable positive-pressure gas barrier between the process side and atmosphere. It helps prevent process media from escaping while limiting particles, moisture, and oil mist from entering the seal gap.

The Plan 74 system provides visual monitoring of buffer gas pressure and flow. It also supports signal output and interlock alarms for system protection. These functions help maintain stable operating conditions and improve dry gas seal reliability.

The system is suitable for pumps handling flammable, volatile, toxic, or otherwise hazardous media. It also suits media with poor lubricity or containing solids and crystals. Plan 74 is particularly useful when a small amount of nitrogen entering the process is acceptable. At the same time, process media must not be released into the atmosphere.