PRO Shaft Seal 1-3/4" Shaft & 3-1/2" TubeThe PSS PRO Shaft Seal is a mechanical face seal utilizing our proven stainless steel and carbon sealing components, but adds a reinforced silicone bellow, we include external rings standard on sizes +2-1/4" and optional on all smaller sizes, a secondary shaft retention collar, 316 Stainless Steel hose clamps (rolled edges & non-perforated) and an optional Nitronic 50 rotor upgrade (for highly corrosive environments). Designed specifically for applications that will require increased durability and resistance to harsh, corrosive, high pressure and otherwise demanding environments. The PSS PRO Shaft Seal is a specialized mechanical seal that is suitable for a variety of applications, with unmatched performance.As with PSS Type A & B Seals, The PRO Shaft Seal is a mechanical face seal. The sealing surface is created between the flat surfaces of the rotating stainless-steel rotor and the stationary carbon flange. The stationary carbon flange is attached to a heavy duty silicone bellow which is attached to the vessel’s stern tube (shaft log), with 316SS hose clamps. The stainless-steel rotor is fitted on the shaft in front of the carbon flange and is used to compress the bellow , the rotor is then secured to the shaft with set-screws and the shaft retention collar is installed. This compression (pre-load) maintains constant contact between the two mating faces of the stainless-steel rotor and carbon flange, allowing the PSS to compensate for the variable axial movement due to propeller thrust. The carbon flange is over-bored to the shaft diameter allowing it to "float" around the shaft and thus compensate for most misalignment and vibration from the drive-line. The stainless-steel rotor is sealed to the shaft by two O-rings that are recessed into the bore of the rotor. These O-rings rotate with the shaft and the stainless-steel rotor, and therefore do not experience wear during operation.Specifications:Temperature Limits: -13°F to 425°F (-25°C to 220°C)Pressure Limits: 40 PSI (2.75 BAR)Shaft RPM Limits: 10,000 RPMCarbon Graphite: Lapped to 4 HLB (0 44" tolerance)316SS / Nitronic 50: Faced to 9 RaBellow Material: Molded formed silicone / fabricProduct Dimensions:Shaft Dia. (A) 1-3/4"Stern Tube Dia. (B) 3-1/2" to 3-5/8"Uncompressed Length (C) 9.268" Approx. Compressed Length 8.268" Rotor Diameter (D) 3.75"Stern Cuff Length (E) 1.3"