Mechanical face seal

PSS · PRO

For 32mm to 95mm (1-1/4" to 3-3/4")

The PSS PRO Shaft Seal is a mechanical face seal utilizing our proven stainless steel and carbon sealing components, but adds a reinforced silicone bellow, 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.

HOW DOES IT WORK ?

Fonctionnement du joint mécanique PSS
  • 1
    Two nitrile o-rings seal the stainless steel rotor to the shaft and will not experience wear.
  • 6
    The Shaft Retention Collar is attached to the shaft and helps retain the propeller or rudder shaft in your vessel in the event of catastrophic failure of the coupling or if the shaft comes free from the coupling.
  • 2
    A primary set screw and a backup set screw (2 sets) are used to secure the stainless steel rotor to the shaft.
  • 7
    Stainless steel rings are fit to the bellow for increased strength, support and durability. External rings come standard on sizes 2-1/4" (60mm) to 3-3/4" (95mm) and optional for smaller sizes.
  • 3
    A seal is created between the two mating faces of the carbon stator and the stainless steel rotor.
  • 8
    316SS hose clamps with rolled edges and non-perforated band.
  • 4
    Raw water is fed to the PSS Shaft Seal for cooling / lubricating the seal faces on high speed vessels.
  • 9
    Hose clamp tail protection, Clamp Jackets.
  • 5
    The stationary carbon stator is attached to the bellow, which is secured to the stern tube (shaft log).

COMPONENTS

SHAFT RETENTION COLLAR

SRC shaft and rudder retention collar
The PYI Shaft Retention Collar is designed to help retain the propeller or rudder shaft in your vessel in the event of catastrophic failure of the coupling or if the shaft comes free from the coupling. The double split design provides the maximum in axial holding power with the benefit of quick and efficient assembly with the shaft installed. Design fully engages the shaft without marring. Easily installed where major disassembly would otherwise be required. Greater axial holding power than set screw or one-piece clamping collars. Effective on hard and soft shafts.

CARBON STATOR

Carbon of PSS PRO
The high density, resin impregnated carbon/graphite stator is a space age composite that is first mixed, molded and then formed under pressure. The blanks are then baked, machined and lapped. The face of our carbon is finished to a flatness of 4 helium light bands (measured .000044" of variation over entire lapped surface). The grade of carbon used in the PSS has an operating temperature over 500° Fahrenheit (+260° Celsius), and cannot melt if the seal runs dry, unlike a rubber lip seal or plastic face seal. The high density of the carbon greatly increases the longevity and wear resistance. Several commercial vessels have recorded over 40,000 (over 4-1/2 years of continuous operation) engine hours on the same, original components. The carbon should not need to be replaced under normal operating conditions.

BELLOW RINGS

Bellow rings of PSS PRO
Stainless steel rings are fit to the bellow for increased strength, support and durability.

ROTOR

rotor of PSS PRO
The PSS stainless steel rotor is slid down the shaft and is secured to the shaft with set screws at 90° for maximum holding power. Precision tolerances are maintained by computer controlled lathes. The faces have a number 9 micro finish and are perpendicular to the bore to prevent run-out as the collar rotates. The carbon graphite stator will polish the face of the rotor during the first few minutes of operation. The stainless steel rotor should not need to be replaced under normal operating conditions. The stainless steel rotor used on the PSS Commercial Shaft Seal are made from 316L stainless steel.

HOSE BARB

Hose Barb of PSS PRO
For high speed vessels (planning hulls or vessels powering over 12 knots) it is required that a positive water supply be plumbed to the PSS Shaft Seal for the purpose of lubricating and cooling the seal faces. There are many sources of water supply, review the PSS Shaft Seal Installation Instructions for more information and note all plumbing must follow the standards and practices of proper boat plumbing. In most cases a slow speed boat that does not have a bearing in the shaft log does not require positive water feed and can simply be "vented". Ideally the vent line will be run at least 2-3 feet above the water line and as close to the center line as possible to ensure the vent hose is never below the water line, even if the boat heels. Review the PSS Shaft Seal Installation Instructions for more details on venting the seal.

BELLOW

Soufflet du joint mécanique PSS PRO
The PSS PRO Shaft Seal bellow provides a good combination of durability, strength and elasticity. It's constructed of four ply aramid / silicone with a flurosilicone outer cover. This flurosilicone cover creates an oil and fuel resistant barrier protecting the exterior surface from the possibility of damage from splash or spill. Both ends of the bellow are sealed. The four ply cloth inlay provides excellent strength and resistance to abrasion. The strength of the bellow is greatly increased by fitting stainless steel hoops in the convolutions of the bellow. This bellow has a continuous operating temperature range of -90°F to +425°F (-70°C to +220°C).

CERTIFICATES

The PSS Shaft Seal has been thoroughly tested and approved by these certifications.
RINA certification

RINA

Bureau Véritas certification

BUREAU VERITAS

APPROVED BY THE AMERICAN BUREAU OF SHIPPING

ABS

vidéos

What is a PSS Shaft Seal ?

Removing the shaft coupling

PSS FAQ

DEALERS

PSS Shaft Seals are available around the world. Use the map below to find the nearest PSS Shaft Seal dealer to you.

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