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PTFE SEALING CORD
EXPANDED
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CONTENTS
Page
Two types – countless applications
4
Material
4
Temperature resistance
4
Chemical resistance
4
Non-toxic
4
Applications
4
Storage and ageing
4
Other expanded PTFE products
5
Provisos
5
Expanded sealing cord in comparison with die-cut and hand-cut gaskets
5
FJ 2916 Universal
• Choice of cord dimensions
6
• Post-compression thickness
7
• Surface pressure in relation to force per unit length of cord
7
FJ 2917A MultiTex
• Choice of cord dimensions
8
• Post-compression thickness
8
Fitting instructions
9
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PTFE SEALING CORD
EXPANDED
temperatures higher than 150°C
and pressures exceeding 40 bar.
Non-toxic
The material is completely nontoxic and meets the food safety
requirements of FDA 21 CFR
177.1550 (a) (1) and (b).
Applications
As PTFE sealing cords are soft
and pliable, they are easily
formed and fitted. The consistency of the material makes the
cords ideal for sealing uneven or
rough-surfaced flanges, including
old or worn flanges.
Two types – countless
applications
Expanded PTFE sealing cord is
an attractive alternative to traditional flat gaskets. Thanks to its
many uses, such cord can be
considered a universal gasket.
Betech Seals offers two types of
sealing cord:
• FJ 2916 Universal
• FJ 2917A MultiTex
FJ 2917A MultiTex is the more
expensive of the two and is recommended for seals where high
surface pressures are concerned.
The cord has the following special properties:
• Extremely low creep
• Extremely high pressure
stability
• Minimum width enlargement
4
Traditional ePTFE cords, including FJ 2916 Universal, tend to
“degrade” when exposed to very
high pressures or temperatures.
Material
Expanded (i.e. foamed) virgin
PTFE with self-adhesive strip on
one side to facilitate fitting.
The material is non-aggressive
and the cord therefore does not
attack the sealing surfaces or
affect them in any way. Leaks and
the damage they cause are thus
prevented.
Temperature resistance
From -240°C to +270°C, transient
temperatures of up to +315°C.
Chemical resistance
Resistant to all media from pH 0
to 14 with the exception of dissolved or molten alkaline metals
and some fluorine compounds at
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The cords are even suitable for
stress sensitive sealing surfaces,
e.g. enamel, glass, plastic,
graphite, ceramic and rubber/
metal, but can of course also be
used for metallic sealing surfaces, e.g. aluminium and steel.
The cords are typically used in
compressors, gearboxes and
pumps, handholes and manholes, heating and ventilation systems, expansion joints, pressure
vessels and heat exchangers.
Due to the purity and chemical
resistance of the material, PTFE
sealing cords are widely used
within the chemical, pharmaceutical and food industries.
Storage and ageing
Sealing cords should be handled
and stored with care and must
never be exposed to pressure or
contaminants.
If stored under the recommended
conditions, no ageing occurs.
The adhesiveness of the backing
strip may, however, be reduced
if the cord is stored under unfavourable conditions.
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PTFE SEALING CORD
EXPANDED
Other expanded
PTFE products
MultiTex expanded PTFE is also
available as:
Round cord
Ø 1 mm to Ø 16 mm without
adhesive strip. Quality FJ 2916D.
Gasket sheets/
die-cut gaskets
0.7 g/cm3 - quality FJ 2917D.
1.0 g/cm3 - quality FJ 2917C.
Sealing tape
For handhole and manhole
covers. Approved to TRD 401,
class C. Quality FJ 2917B.
Handhole and manhole gaskets
Die-cut gaskets with steel inlay.
Approved to TRD 401, class C.
Quality FJ 2917F.
Provisos
The data given in this brochure
represent our current knowledge.
Material performance and durability depend on the application
and medium concerned.
Conditions during use are outside
our control.
We therefore reserve the right to
alter product data and properties
without prior notice.
Expanded sealing cord
in comparison with die-cut and hand-cut gaskets
Die-cut or hand-cut
gasket
ePTFE cord
Advantages of
ePTFE cord
Separate gasket required
for each flange type/size.
Same cord suitable for
many flange types/
sizes.
• Fewer stocks
• Lower costs
Delivery time for die-cut
gaskets; work involved in
hand-cutting gaskets.
Universal gasket which
is always in stock.
• Less time consuming
• Lower costs
Material is wasted.
No material is wasted.
• Lower costs
Requires expensive
tools.
No need for expensive
tools.
• Lower costs
Limited to specific
shapes and sizes.
Gasket always fits as it
is made from cord on
site.
• Less time consuming
• Greater assurance of
correct fit
• Lower costs
Difficulties in handling
and fitting large gaskets.
Easily shaped and
fitted.
• Greater assurance of
tight seal
• Less rejection and
fewer faults
• Less time consuming
• Lower costs
The larger the gasket, the greater the advantages!
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PTFE SEALING CORD
FJ 2916 UNIVERSAL
Choice of cord dimensions
Dimensions
width x thickness
mm
Roll length
m
Flange size
ND
3 x 1.5
25
up to 50
5 x 2.0
10
up to 200
7 x 2.5
10
up to 600
10 x 3.0
10
up to 1500
12 x 4.0
10
up to 1500
14 x 5.0
10
from 1500
17 x 6.0
5
from 1500
20 x 7.0
5
from 1500
28 x 5.0
5
from 1500
50 x 5.0
5
from 1500
Tensile strength
>50 N/mm2
Typical sealing values
σVU/ Q 01 = 20 MPa
σBU/ Q 01 = 5 MPa
Tests and approvals
• BAM Tgb. no. 4.1.332/94
(oxygen, 100 bar, 90°C)
• DVGW reg. no.
DG-5127AQ1282
(-10°C to 70°C, max. 16 bar)
• TÜV test no. AW6/3231-98
As a rule of thumb, we recommend that cord width is between 1/3 and 1/2 the width
of the sealing surface.
6
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PTFE SEALING CORD
FJ 2916 UNIVERSAL
Post-compression thickness
7
Temperature: 20°C
6
Cord dimensions: 14 x 5 mm
Cord thickness (mm)
20 x 7
Surface pressure: 30 MPa
5
Effective thickness: 0.9 mm
17 x 6
4
14 x 5
12 x 4
3
10 x 3
2
7 x 2,5
5x2
3 x 1,5
1
0
0
1
10
100
Surface pressure (MPa)
Effective cord width (bD mm)
Surface pressure in relation to force per unit length of cord
45 MPa
50
48
46
44
42
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
50 MPa
55 MPa
40 MPa
20 x 7
60 MPa
35 MPa
65 MPa
30 MPa
17 x 6
25 MPa
20 MPa
14 x 5
15 MPa
70 MPa
75 MPa
80 MPa
10 MPa
12 x 4
5 MPa
10 x 3
7 x 2,5
Temperature: 20°C
Cord dimensions: 14 x 5 mm
bolt force
Linear force ( total
length of cord ): 700 N/mm
5x2
Effective corde width (bD): 24 mm
3 x 1,5
Resulting surface pressure: approx. 30 MPa
0
500
1000
1500
2000
2500
Force per unit length of cord (N/mm)
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PTFE SEALING CORD
FJ 2917A MULTITEX
Choice of cord dimensions
Flange type is crucial in determining correct cord dimensions. The
more stress sensitive the flange
is, the wider and thicker the cord
should be. Se the diagram on the
right, where steel flanges are considered to have low stress sensitivity while enamelled flanges are
considered to have high stress
sensitivity.
Steel flanges (yellow area)
We recommend that sealing cord
width be a size smaller than sealing surface width.
Width
mm
10
15
20
25
30
35
40
45
50
55
60
65
2 mm
10 / 25 / 50
10 / 25 / 50
10 / 25 / 50
10 / 15 / 25
10 / 15 / 25
5 / 10 / 15 / 25
5 / 10 / 15
5 / 10 / 15
Thickness mm / Spool-length m
3 mm
6 mm
9 mm
10 / 25 / 50
10 / 25 / 50
10 / 25 / 50
10 / 15 / 25
10 / 15 / 25
10 / 15 / 25
10 / 15 / 25
10 / 15 / 25
5 / 10 / 15 / 25
5 / 10 / 15 / 25 5 / 10 / 15 / 25 5 / 10 / 15 / 25
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10 / 15
5 / 10
5 / 10
Steel flange
Enamelled flanges (green area)
Enamelled flange
The colours illustrate increasing stress sensitivity for steel
and enamelled flanges respectively.
Sealing cord width should equal
maximum sealing surface width.
Surface pressure
Post-compression thickness
3.0 mm sealing cord
Max. 150 MPa
100
To DIN 28090/DIN 28091-T3.
Tests and approvals
• BAM Tgb. no. II-431/2000
• Tested for use in flanged joints
of steel, copper or copper
alloys for gaseous oxygen up
to 40 bar and 160°C and for
liquid oxygen with no pressure
limitation.
• Meets requirements for >10-4
hPa x l/cs x m of TA air
(VDI 2440, Nov. 2000).
8
90
Post-compression thickness (%)
Typical sealing values:
σVU/ Q 01 = 20 MPa
σBU/ Q 01 = 5 MPa
80
70
60
50
20 °C
40
40 °C
60 °C
30
80 °C
20
150 °C
200 °C
10
0
0
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5
10
15
20
25
30
Sealing pressure (MPa)
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35
40
PTFE SEALING CORD
FITTING INSTRUCTIONS
1. Clean dirt and any remains of
the previous gasket from the
sealing surfaces and check
the surfaces for damage.
Figure a
g
Cuttin
Flange
Sealing
surface
Bolt hole
Overlap = approx. 3 x cord width
Figure b
5
2
7
3
FJ 2916 Universal
Cut the ends of the sealing
cord to allow them to overlap
one another by about 1 cm
(figure c).
4. Tighten the bolts evenly in
several steps (e.g. 20%, 70%
and 100% of recommended
torque). Tighten the bolts in
accordance with the pattern
shown in figure b.
20% addition
MultiTex sealing cord
2. As dirt on the adhesive strip
may cause the gasket to slide,
remove the covering tape
gradually as the cord is fitted.
Position the cord at the centre
of the clean, grease-free sealing surface, starting beside a
bolt hole.
3. FJ 2917A MultiTex
Cut the ends of the sealing
cord obliquely using a sharp
knife to form a closed ring
(figure a).
Approx. 2 x cord width
4
8
1
6
Figure c
5. Tighten the bolts in several
steps (e.g. 20%, 70% and
100% of recommended
surface pressure). We recommend that the bolts be
continuously checked and
retightened until normal operating temperature has been
achieved.
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Betech Seals
– Improving your products
Betech Seals was founded in 1922 and is today one of the market’s leading suppliers
of gaskets, seals, mouldings, bellows, vibration dampers, and sheet and plate work.
At our factory in Bramming, we produce customer-specific solutions within machine
and hand-made seals. We also perform sheet and plate work on state-of-the-art
machinery.
In addition, we work closely with some of the world’s most renowned manufacturers,
including Hallite, Flexitallic, Reinz, and Barry Controls, all of which meet our stringent
quality requirements.
Dialogue with a highly qualified partner
At Betech Seals, some of the best and most experienced specialists in the trade are
available to provide customers with unique, solution-oriented consultancy services.
The dialogue begins as early as at the design stage and continues in close collaboration with our customers’ development departments. This partnership results in durable,
high-quality solutions which, at the end of the day, provide customers with considerable savings and better products.
Added value for customers
Improving your products – our company slogan. It expresses the essence of our mission.
Optimising our customers’ products is a challenging goal. It commits us. To keeping
our promise of adding value over and above the product itself. The result is efficient
production and better, more competitive products.
201 GB 01-2007
Betech Seals A/S
Betech Seals A/S
• Vesterlundvej 4 • DK-2730 Herlev • Tel. +45 4485 8100
• Industrivej 29 • DK-6740 Bramming • Tel. +45 7656 2600
info@betechseals.dk • www.betechseals.dk
•
•
Fax +45 4492 7800
Fax +45 7510 1558