Abstract: A sealing assembly to seal about a rotary shaft of a vertical pump assembly, the pump assembly including an impeller rotating within a cavity to pressurize a fluid entering the cavity, the sealing assembly including a pump housing and a gas filled enclosed chamber formed within said housing and in communication with the cavity. A liquid filled chamber in communication with the gas filled chamber prevents the escape of gas from the gas filled chamber when the fluid enters the gas filled chamber. A rotary seal inhibits the flow of liquid from the liquid filled chamber into the environment surrounding the housing. The flow of fluid into the gas filled chamber compresses the gas within the gas filled chamber to form a buffer zone to prevent contact between the fluid and the rotary seal.