JB/T 8872-2016Technical requirements for carbon-graphite sealing rings for mechanical seals (English PDF)

Foreword

This Standard is drafted in accordance with the rules given in GB/T 1.1-2009.

This Standard replaces JB/T 8872-2002 "Specification for carbon-graphite sealing ring for mechanical seals". As compared with JB/T 8872-2002, the main technical changes of this Standard are as follows:

- Adjust the physical and mechanical property parameters of some carbon-graphite sealing ring materials;

- Modify the hydraulic test method for the graphite ring;

- Modify the inspection provisions.

1 Scope

This Standard specifies the product classification, requirements, inspection methods, inspection provisions, marking, packaging, transportation, and storage, etc. of carbon-graphite sealing ring for mechanical seals.

This Standard applies to the material selection and design of carbon-graphite sealing ring for mechanical seals.

2 Normative references

The following documents are indispensable for the application of this document.

For the dated references, only the editions with the dates indicated are applicable to this document. For the undated references, the latest edition (including all the amendments) are applicable to this document.

GB/T 1184-1996 Geometrical tolerancing - Geometrical tolerance for features without individual tolerance indications

GB/T 1958 Geometrical Product Specifications (GPS) - Geometrical tolerance - Verification

GB/T 2828.1 Sampling procedures for inspection by attributes - Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection

GB/T 3177 Geometrical product specifications (GPS) - Inspection of plain workpiece sizes

JB/T 2934 Carbon material and carbon products for mechanical engineering

JB/T 8133.4 Test Method for Physical-chemical Properties of Electrical Carbon Product - Part 4: Shore Hardness

JB/T 8133.7 Test Method for Physical-chemical Properties of Electrical Carbon Product - Part 7: Transverse Strength

JB/T 8133.8 Test Method for Physical-chemical Properties of Electrical Carbon Product - Part 8: Compressive Strength

4 Requirements

4.5 The parallelism of the seal face of planar sealing ring to the end face which the auxiliary sealing ring contacts, in accordance with GB/T 1184-1996, has Grade 7 tolerance.

4.6 The surface roughness of the contact surface between the planar sealing ring and the auxiliary sealing ring is not more than Ra 3.2 µm.

4.7 The size tolerances of the static ring and rotating ring of planar sealing ring and of the outer circle and inner hole in contact with the auxiliary sealing ring are h8 or H8.

4.8 The perpendicularity of the seal face of static ring and rotating ring of planar sealing ring to the outer circle and inner hole in contact with the auxiliary sealing ring, in accordance with GB/T 1184-1996, has Grade 7 tolerance.

4.9 The carbon-graphite sealing ring shall be tested for hydraulic pressure (internal pressure). Sealing rings for non-balanced and balanced mechanical seals shall have a test pressure of 0.8 MPa and 1.6 MPa respectively for 10 min and shall not leak. If there are special requirements, it shall be carried out according to the drawings.

4.10 The carbon-graphite sealing ring is not allowed to have cracks, oxidation, delamination, penetrating pitting, pores, impervious impregnation.

5 Inspection methods

5.2 The hydraulic inspection of carbon-graphite sealing ring material is carried out on a dedicated hydraulic test device.

5.3 The size deviation and geometrical tolerance of carbon-graphite sealing ring are respectively inspected according to the provisions of GB/T 3177 and GB/T 1958.

5.4 USE an intuitive method to inspect the surface defects of carbon-graphite sealing ring.

6 Inspection provisions