Legend
- F. flushing
- V. vent (if required)
- GBI. buffer gas inlet (plugged)
- CSV. containment seal vent (plugged)
- CSD. containment seal drain (plugged)
- FI. flow indicator
- FIL. coalescing filter, used to ensure that the solid particles and/or liquid which might be present in the supplied buffer gas do not contaminate the seals
- FSH. high flow switch
- PCV. pressure control valve used to limit buffer gas pressure to prevent reverse pressurization of the inner seal and/or limit pressure applied to the containment seal
- PI. pressure indicator
- PSL. low pressure switch
- 1. Buffer gas panel (feeding unit)
- 2. Vendor
- 3. Purchaser
- 4. If required
Low pressure installation for outer seal containment. Buffer (quenching) gas is fed externally to the outer seal of the double system. Buffer (quenching) gas may be used only to dilute seal leakage or in conjunction with Plan 75 or 76 to help sweep gas vapours leakage into a closed collection system (discharge system) or liquid leakage to the tank. The system enables leakage monitoring. Pressure of the buffer (quenching) gas is lower than process pressure (at the technological process side) of the inner seal.
