Mechanical Face Seal Assembly
Sourced from the ASLE Seals Special Publication
1. Torque Pin
2. Coil Spring
3. Free Length
4. Piston-Ring Carrier
5. Primary-Seal Carrier
6. Primary Seal Ring
7. Seal Bore
8. Sealing Face
9. Sealing-Face Inner Diameter
10. Sealing-Face Outer Diameter
11. Sealing-Face Width
12. Seal Nose
13. Secondary-Seal Land
14. Secondary-Seal Land Diameter
15. Piston Ring
1. Torque Pin: A type of anti-rotation device. It consists of a metal pin, one end of which fits loosely in a hole or slot in the primary-seal carrier with the other end being solidly attached to the secondary-seal carrier.
2. Coil Spring: A type of spring which is formed from wire wrapped in a helix. The spring so formed encloses a volume in the shape of a right cylinder. It is normally used in multiples, with the individual springs oriented about the circumference of a seal assembly. Thus placed, the springs transmit a uniform closing force on the sealing face.
3. Free Length: The uncompressed axial length of a face-seal assembly. The term is also applicable to a spring or a bellows.
4. Piston-Ring Carrier: Also known as Secondary Seal Carrier: That component of a face seal assembly or its surrounding stationary structure which contains grooves or slots into which the secondary seals are mounted.
5. Primary-Seal Carrier: That component of a face seal assembly or its surrounding stationary structure which contains grooves or slots into which the secondary seals are mounted.
6. Primary Seal Ring: A ring-shaped member in a face seal or in a ring seal. It is normally made of carbon. The face of the primary-seal ring forms the primary seal with the mating ring.
7. Seal Bore: The diameter which corresponds to the innermost surface of a face-seal assembly. The surface referred to can be on the primary-seal ring, the primary-seal carrier, or the secondary-seal carrier, whichever has the smallest inner diameter.
8. Sealing Face: The lapped surface of the seal, which comes in closest proximity to the face of the mating ring of a face seal, thus forming the primary seal. With reference to lip seals, the preferred term is ‘seal contact surface’.
9. Sealing-Face Inner Diameter: The diameter which corresponds to the inner edge of the sealing face on the seal nose.
10. Sealing-Face Outer Diameter: The diameter which corresponds to the outer edge of the sealing face on the seal nose.
11. Sealing-Face Width: The radial distance from the inside edge to the outside edge of the nose part of the sealing face.
12. Seal Nose: The part of the primary seal ring of a face seal which comes in closest proximity to the mating surface and which together with the mating surface, forms the primary seal.
13. Secondary-Seal Land: The cylindrical surface against which the secondary seal rides to effect the secondary sealing.
14. Secondary-Seal Land Diameter: The diameter of the surface of the face-seal assembly which contacts the secondary seal. The sealing land may also be on a stationary surface which is not a part of the seal assembly. For a balanced seal, this diameter is also the balance diameter.
15. Piston Ring: A ring with a basically rectangular cross-section and a single small gap. It seals by expanding or contracting against a mating cylindrical surface.
