three dimensional crystal system
the hardest substance in nature
excellent electrical insulation
black silver colour
hexagonal crystal system - plane structure
good conductor of electricity
soft - good sealing performance
good lubricant (low friction)
RAW MATERIAL CRYSTALLISED GRAPHITE
•Layer of plane hexagonally arranged carbon
atoms: PLANE OR LAMELLAR STRUCTURE
• sliding of planes
against each other:
Natural graphite flake special chemical and thermal process
Popcorn principle expansion 400 times its original size
Volume of 1 Litre = only 2 to 3g
EXPANDED FLAKES (WORMS)
Flexible graphite - Manufacturing process
Treatment withTreatment with
oxidising mediumoxidising medium
HH22SOSO4,4,, HNO, HNO33 & 100°C& 100°C
Water rinseWater rinse
and dryingand drying
Flexible bindingFlexible binding
from 0.2 to 1.0 mm
can be produced.
GRAFILIT SF pure graphite foil without insertion
graphite foil bonded (adhesive) to smooth stainless steel
insertion (AISI 316; 0,05 mm)
graphite mechanically bonded to a tanged stainless-steel
insertion (AISI 316; 0,1mm)
graphite reinforced with expanded stainless-steel
insertion (AISI 316L)
FLEXIBLE GRAPHITE SHEETS
• no health hazard
• no ageing because of absence of binder
• wide range of operating temperatures (from - 200 up to+ 550°C)
• high compressibility
• excellent adaptability to flange surfaces
• creep resistance at high temperature
• good sealing properties
• good general chemical resistance
• correspond to DIN 28091-4
PROPERTIES OF EXPANDED
• organic and non-organic acids
• petrol and petroleum products
• alcohol, ketons and solvents
• mineral oils
• heat transfer oils
• refrigerating products (freons)
Exceptions are strong oxidising media such as sulphur
trioxide, concentrated nitric, chloric and sulphuric acid...
Grafilit EM consists of high-quality expanded
graphite and an expanded metal insert made of
acid-proof stainless steel AISI 316L – 0,35mm or
1.4404, mesh aperture 3 mm (Passo 3).
The purity of the graphite is at least 98%!
Thermal and mechanical loading capacity from
- 240°C to + 550°C (in inert atmosphere up to
3000°C) with simultaneous high pressures.
Chemical resistance against all organic and
inorganic acids (except for oxidizing acids),
alkalines and solvents.
Excellent resistance to steam and thermal oils !
Properties and application Available options
Thickness: 1,0 – 1,5 – 2,0 – 3,0mm
Benefits compared to Tanged Graphite
Higher tightness up to 50% see Fuji Film !
Homogeneous load distribution especially with narrow gaskets !
Better use of surface pressure, as no crowns has to be bent !
Due to open structure, better adaptability in between flange faces !
Higher compressibility (45%-50%) better recovery/elasticity !
High Blow out resistance !
Lower leakage rate when unloading !
Higher flexible sheet less vulnerable to cracks/breaking !
Easy to cut, even with sharp scissors !
Provides high performant seal even when segmented Case Study !
Easy handling limited risk for injuries !
Grafilit EM is considered to be A very Forgivable Gasket Material !
GRAFILIT EMTANGED GRAPHITE
Oil & Gas
Pulp & Paper
Thermal Oil Pumps
Thermal Oil Construction
You name it !
Some important references:Some important references:
CUTTING on CNC FOR FINISHING
• Expanded graphite is not influenced by ageing
process caused by temperature, ozone, UV rays …
• To ensure optimal conditions, store the graphite
sheets and/ or gaskets in following conditions:
• Temperature of storage: -20°C to +50°C
• Clean and dry environment – no humidity !
• Place gaskets horizontally – avoid hanging on
hooks or folding which could cause cracking
• Protect sheets and gaskets against damaging
•Specified conditions can ensure you a shelf life even
longer than 15 years !
• Coal Fired Power Station in UK from 60’s
• Gasket on steam injectors for driving turbines
• Conditions: T=565°C
P= 200bar (simultaneously !!)
OD 140 x ID100 x 1,5mm (dove-tail joint !!)
• Since ban of CAF nothing but problems
• Previous supplier could not offer solution
• Since Oct 2001 Graphite with expanded stainless steel has
been used without replacement !
Case Study : Graphite with expanded stainless
Head gaskets : Air Compressors – PET Bottle production
Problem : with CNAF, tanged graphite,.. leakages !
Solution : Expanded graphite with expanded st.steel
Pressure : 0 - 40 bars
T° : up to 220°C
Meets global fugitive emission regulations
One fits all - standardize your gasket diversity
Maximize plant safety
Reduce your costs
DONIT Certification for quality assurance
A PERFECT FIT