API Plan 52

• Provides lubrication and cooling to the contacting wet outboard safety backup seal.
• The pumped fluid will not become contaminated.
• The pumped media does not leak directly to atmosphere.
• No pressurization required for the reservoir as is case of a Plan 53A.
• Provision of cooling coil inside the reservoir or an external water or air cooler takes care of the heat removal.
• Uses an internal circulating device to ensure buffer liquid circulation.

• For flashing services – for example light hydrocarbons, high vapor pressure fluids. Can also be used for non-flashing services.
• For services where product contamination by a barrier fluid is not acceptable

• Do not use for contaminated and polymerizing media.
• Use a restriction orifice plate in the vent line to maintain a back pressure in the reservoir.
• Vent the system before start-up. Later ensure that the vent line always remains open and is connected to the flare.
• The piping from the seal to the reservoir should be self-venting.
• Sense the seal inlet and outlet line temperatures. Difference in the temperatures is an indication of proper flow.
• An increase in either the reservoir pressure or reservoir level is an indication of inboard seal leakage.
• A decrease in the reservoir level is an indication of outboard seal leakage.
• Ensure the compatibility of buffer liquid with the pump media.
• The buffer liquid shall be maintained at a pressure less than the seal chamber pressure and less than 2.8 bar (40 PSI).
• Check buffer liquid quality at regular intervals and replace if required.

• High vapor pressure, flashing media.
• Clean, non-polymerizing.
• Hazardous / environmentally harmful if leaked directly to the atmosphere.

• Between seals
• Buffer system (p_sealchamber > p_betweenseals)
• Lubrication and flushing for the outboard seal and cooling for inboard as well as outboard seals.

2CW-CW