Overview of Chemical Department Standards for Pipeline Sealing Gaskets (European System):

1. HG20606-97 (non-metallic flat gasket for steel pipe flanges) pressure rating: PN0.25Mpa, PN0.6Mpa, PN1.0Mpa, PN1.6Mpa, PN2.5Mpa, PN4.0Mpa. Sealing surface forms are divided into: FF type (full plane), RF, MFM, TG (protruding surface, concave convex surface, tenon groove surface), RF-E type (protruding surface, with edge wrapping).

2. HG20607-97 (PTFE coated gasket for steel pipe flanges) pressure rating: PN0.6Mpa, PN1.0Mpa, PN2.5Mpa, PN4.0Mpa. The sealing surface forms are divided into PMF (machined wing shape), PMS (machined rectangle), and PFT (folded wrap shape).

3. HG20608-97 (flexible graphite composite gasket for steel pipe flanges) pressure rating: PN1.0Mpa, PN1.6Mpa, PN2.5Mpa, PN4.0Mpa, PN6.3Mpa. Sealing surface forms include RF, MFM, TG (protruding surface, concave convex surface, tenon groove surface), RF-E (protruding surface, with inner edge wrapping).

4. HG20609-97 (metal wrapped gasket for steel pipe flanges) pressure rating: PN2.5Mpa, PN4.0Mpa, PN6.3Mpa, PN10.0Mpa. There is no distinction between seal cover forms.

5. HG20610-97 (Spiral wound gasket for steel pipe flanges) pressure rating: PN1.6Mpa, PN2.5Mpa, PN4.0Mpa, PN6.3Mpa, PN10.0Mpa, PN16.0Mpa. Sealing surface form:

A (for basic mortise and tenon surfaces)

B (for inner ring concave convex surfaces)

C (for use with outer annular protrusions)

D (for inner and outer annular protrusions)