TP50-160/2 Shaft Seals Manual

3
Shaft seals
Type designation
Type designation to EN 12756
The EN standard describes the mechanical design of
shaft seals and the combination of materials.
The EN 12756 standard contains
• type key
• material key.
Purpose
Specifications to external Grundfos shaft seal suppliers
are made according to the type designation coding sys-
tem of EN 12 756.
Type designation
A complete type designation for shaft seals according
to EN 12756 consists of
• type code
• material code.
Type key
The EN 12756 contains the following type key:
Material key
The materials of the individual main components are
indicated by means of a material code consisting of five
letters.
Example N U 012 S 0 - U B E G G
Type code
Material code
Example N U 012 S 0
Version:
N = Standard assembly length
K = Short assembly length
X = Other assembly length
Shaft seal type:
U = Unbalanced
B = Balanced
Nominal diameter:
The diameter (shaft diameter) in mm
Example: 12 mm shaft = 012
Direction of rotation:
R = Right-hand rotation (i.e. clockwise rotation of the
seal unit when viewed from the seat)
L = Left-hand rotation (i.e. counterclockwise rotation
of the seal unit when viewed from the seat)
S = Capability of rotation in either direction
Retention against rotation of the seat:
0 = Without retention
1 = With retention
Example (1)U (2)B (3)E (4)G (5)G
Material of rotating seal face
Material of stationary seat
Material of secondary seal
Material of springs
Material of other components