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This standard is prepared in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 6556-1994 Type, main dimension, material and marking of mechanical seals. In addition to a number of editorial changes, the following technical changes have been made with respect to GB/T 6556-1994:
— addition of the BU-type double-end mechanical seals;
— adjustment of the marking of mechanical seals.
This standard was proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of the SAC/TC 491 National Technical Committee on Mechanical Seal of Standardization Administration of China.
The previous edition of the standard replaced by this standard is as follows:
— GB/T 6556-1994.
Type, main dimension, material and marking of mechanical seals
1 Scope
This standard specifies the type, main dimension, marking and material code of mechanical seals for centrifugal pumps and similar rotating machinery.
This standard is applicable to single and double mechanical seals.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated reference, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 1804-2000 General tolerances — Tolerances for linear and angular dimensions without individual tolerance indications
GB/T 10444 Method of type establishment for mechanical seals
3 Type and main dimension
3.1 General requirements
Various types of mechanical seals can be adopted with reference to the structure shown in Figures 1 to 6, but shall follow the given dimensions. The figures show examples of using O-ring as stationary ring auxiliary seals, and seals of other cross-section types may also be used as stationary ring auxiliary seals. Dimensional tolerances not specified shall be in accordance with Class F in GB/T 1804-2000.
3. 2 Types of single mechanical seals
Type U: Unbalanced single mechanical seal, see Figure 1.
Type B: Balanced single mechanical seal, see Figure 2.
Figure 1
Figure 2
3. 3 Types of double mechanical seals
Type UU: Double mechanical seal with unbalanced structure at both ends, see Figure 3.
Type BB: Double mechanical seal with balanced structure at both ends, see Figure 4.
Type UB: Double mechanical seal with unbalanced structure at medium end (inboard) and balanced structure at atmosphere end (outboard), see Figure 5.
Type BU: Double mechanical seal with balanced structure at medium end (inboard) and unbalanced structure at atmosphere end (outboard), see Figure 6.
Figure 3
Figure 4
Figure 5
Figure 6
3.4 Anti-rotation and limit of stationary ring
The dimensions of static circumferential anti-rotation and axial limit structure of mechanical seals shall follow the following provisions:
a) The stationary ring anti-rotation structure is applicable to balanced and unbalanced mechanical seals. The design of the stationary ring may adopt the dowel pin structure either on the radial position (Figure 7) or axial position (Figure 8). Other static ring anti-rotation structures are designed by the manufacturer itself.
Figure 7
Figure 8
b) The stationary ring axial limit structure is suitable for the medium end (inboard) of single mechanical seal and double mechanical seal. The axial limit structure of stationary ring includes unbalanced mechanical seal axial limit structure (Figure 9) and non-balanced mechanical seal stationary ring axial limit structure (Figure 10). The axial limit structure of other stationary rings is designed by the manufacturer itself. In order to ensure the reliable installation of the spacing ring, the outer diameter d9 of the spacing ring must be at least 2 mm larger than the inner diameter d4 of the seal cavity.
Figure 9
Figure 10
3. 5 Main dimensions
See Table 1.
Foreword i
1 Scope
2 Normative References
3 Type and main dimension
4 Markings
5 Material codes
