PSS 02-120M-712 - Dripless Shaft Seal 120 mm, 7 1/2" Stern Tube

PSS 02-120M-712 - Dripless Shaft Seal 120 mm, 7 1/2" Stern Tube

The PSS 02-120M-712 Dripless Shaft Seal is engineered for optimal performance in marine environments. This mechanical face seal features a unique design that ensures a reliable and leak-free operation, making it ideal for stern tube applications.

The Type B PSS Shaft Seal operates with a mechanical face seal, where the sealing surface is formed between the flat surfaces of a rotating stainless-steel rotor and a stationary carbon flange. The carbon flange is securely attached to the bellow's front side with hose clamps, while the back end of the bellow fits over the stern tube, also secured with hose clamps. The stainless-steel rotor is mounted on the shaft in front of the carbon flange and compresses the bellow before being fastened to the shaft with set-screws. This pre-load ensures constant contact between the rotor and flange, allowing the seal to adapt to variable movement caused by propeller thrust.

Additionally, the carbon flange is designed to float around the shaft, accommodating misalignment and vibration. The stainless-steel rotor is sealed to the shaft with two recessed O-rings that rotate with it, preventing wear during operation.

Temperature Limits: -13°F to 425°F (-25°C to 220°C)
Pressure Limits: 50 PSI (3.5 BAR)
Shaft RPM Limits: 7,000 RPM
Carbon Graphite: Lapped to 4 HLB (0.000044" tolerance)
316SS / Nitronic 50: Faced to 9-12 Ra
Bellows Material: Mandrel formed silicone / fabric

Part #: 02-120M-712
Shaft Dia. (A): 120mm
Stern Tube Dia. (B): 7-1/2" to 7-5/8"
Approx. Length (C): 13.742"
Approx. Compression: 1" to 1-1/4"
Rotor Diameter (D): 7.875"
Stern Cuff Length (E): 2.5"