Abstract: A novel shaft seal suitable for use on agitator shafts and pump shafts such as those commonly found in industrial chemical process equipment, said seal comprising a conventional mechanical seal in combination with packing of a particular material of construction, configuration and which is held under substantially constant compression, such that when fluid is provided under pressure into a stuffing box containing such packing, the fluid will flow through the packing into the process stream with sufficient velocity to prevent process fluid from flowing back into the stuffing box, and yet with insufficient volume rate of flow to cause significant dilution of the process fluid.