DESCRIPTION
A Jacketed Gasket is comprised
of a soft pliable core inside a metallic jacket.
METALLIC JACKET
Almost any metal or alloy found
in sheet form can be used as a jacket; its choice must take into
consideration the fluid to be sealed. The metallic jacket is 0.016 in (0.4
mm) to 0.020 in (0.5 mm) thick.
FILLER
The standard filler material is
Flexible Graphite. Other fillers like ceramic, PTFE or another metal
(corrugated, flat, or serrated) can be used.
STYLES
AND APPLICATIONS
STYLE 920
The style 920 is a round single jacket gasket. Used in applications where
the seating stress and width are limited. It can be manufactured in circular
or oval shape. The maximum gasket width is 1/4 (6.4 mm) and the standard
thickness is 3/32 in (2.4 mm).
STYLE 923
The style 923 is a flat double jacket gasket. Its most typical applications
are in Heat Exchangers. ASME B 16.20 shows the gasket dimensions for ANSI B
16.5 flanges. The standard thickness is 1/8 in (3.2 mm). This style is also
used in large size reactors in chemical plants. Another important use is for
flanges in the large, low pressure ducting in Steel Mill Blast Furnaces. To
compensate for distortions and irregularities of these flanges gaskets have
the thickness from 5/32 in (4 mm) to 1/4 in (6 mm).
STYLE 926
Similar to style 923 but the metallic jacket is corrugated. The corrugations
act as a labyrinth.
STYLE 929
Similar to style 926 with a grooved metallic filler. Used in applications
where it is necessary to have a gasket without non-metallic materials,
temperature limits and chemical resistance depend upon of the metal only.
DESIGN
The following recommendations are based on successful
practical applications: Gaskets confined by the inside and outside
diameters:Gasket inside diameter = groove inside diameter plus 1/16
in (1.6 mm).
- Gasket outside diameter = groove outside diameter
less 1/16 in (1.6 mm).
Gaskets confined by outside diameter:
- Gasket inside diameter = flange inside diameter plus
a minimum of 1/8 in (3.2 mm).
- Gasket outside diameter = groove outside diameter
less 1/16 in (1.6 mm).
Non confined gaskets:
- Gasket inside diameter = flange inside diameter pIus
1/8 in (3.2 mm).
- Gasket outside diameter = bolt circle diameter less
bolt diameter.
