unilion spring-energised engineered plastic seals · unilion® spring-energised engineered plastic...

Unilion® spring-energised engineered plastic seals

High Performance Sealing Technology

Issue 1

• Spring-energised for high capability sealing

• Low friction for smooth operation

• Static, rotary & reciprocating applications

• Excellent performance at high & low pressures

• Wide temperature range

Unilion® spring-energised seals

To order or get further details, call your local contact shown on rear cover or listed at www.jameswalker.biz2

With the Unilion® range, James Walker provides industry worldwide with the high-performance answer to fluid sealing problems where conventional products fail to give the integrity or reliability required.

Spring-energised seals are far from new – we have been manufacturing them since the 1940s. But we now offer a full range of Unilion precision-engineered products that meet the following parameters:

• Used successfully on applications at up to 103MPa/15,000psi.

• Cryogenic duties down to -260°C.

• Temperature excursions up to +300°C.

• Resistance to corrosive media.

• Efficient dynamic operation following long stationary periods.

Based on these operational benefits, we recommend Unilionfor applications that preclude the use of more conventionalelastomeric/polymeric seals on arduous duties in areas suchas:

• Oil and petrochemical.

• Cryogenic plant.

• Aerospace.

• Food and pharmaceutical processing.

• Automotive and general industry.

Moreover, Unilion seals have no storage period limitation. They can safely be held in stock on-site to meet OEM and maintenance requirements.

As a single Unilion can often perform three sealing duties – static, reciprocating and rotary – this can also reduce your stockholding requirements and simplify inventory control.

Contents Page

Unilion introduction 3

Seal jacket materials 4-5

Seal spring materials 6

Unilion seal diameter details 6

Seal technical details 7

Unilion types J01 to J10 standard profiles 8

Unilion types J20 to J29 standard profiles 9

Unilion types J30 & J31 standard profiles 10

How to order/specify your Unilion® seals 10

Unilion back-up rings 11

Hardware design − Rod sealing 12

Hardware design − Piston sealing 13

Hardware design − Rod or shaft sealing with flange 14

Hardware design – Axial sealing 15

Appendix 1: Unilion Fitting Guide 16-17

Appendix 2: Engineering in Fluolion® PTFE 18-19

Unilion enquiry form 20-21

Technical guides 22

General information 23

James Walker worldwide support & distribution 24


Unilion® introduction

To order or get further details, call your local contact shown on rear cover or listed at www.jameswalker.biz 3

Background to successJames Walker has vast experience of working with PTFE and engineering polymers to exacting specifications.

We have been solving industry’s fluid sealing problems by the design, development and manufacture of products in these materials since 1948, when PTFE was classed as a strategic material and available only on a special licence from the USA.

Since then, our research and development teams have identified prime roles for fluoropolymers and other engineering polymers in high integrity seals for static and dynamic mechanisms that need to operate in the harshest of environments.

Our chemists and engineers regularly push back the boundaries of materials technology to develop new techniques for making, forming and machining polymers.

.

The expertise for this exacting work is vested in our sites near Greenock, Scotland and Antwerp, Belgium. At these locations, we have technologists, skilled workforces and specialised plant all dedicated to PTFE and engineering plastics.

Our manufacturing capabilities range from prototype development to large scale production − using fully automated CNC machinery required for achieving the precision needed for Unilion® production.

How the Unilion® seal worksUnilion® seals are based on the ‘U’ ring principle. The lips of each seal are initially energised by corrosion resistant metal springs of helicoil, ‘U’ spring, or ‘U’ finger spring design, according to the seal type.

Helicoil spring

‘U’ finger spring

Full contact spring

The spring energises the Unilion seal by providing resilience to the PTFE lips. This radial stress keeps the sealing lips in contact with the shaft/piston and cylinder before system pressure is applied. It also compensates for any slight eccentricity cause by misalignment in the equipment, manufacturing tolerances, bedding-in wear or thermal movement.

When applied, the system pressure enhances the spring action and increases fluid sealing efficiency. Thus radial stress always exceeds the pressure to be sealed. The flat heel of the seal sits firmly in the machined housing groove to keep the lips set at the correct angle for efficient operation.

Unilion® spring energised

Spring & pressure energised

The result is a long-life, low-friction seal with negligible leakage – even under physically demanding operating conditions involving highly corrosive fluid media.

Unilion® seal jacket materials


Material nameand description

Jacketmaterial

codeColour Applications

Temperature range –

continuous use(°C)

Fluolion® 01Virgin PTFE

01 WhiteExcellent for light dynamic and static service. Low gas permeability. Good cryogenic properties. Conforms to FDA 21 CFR 177.1550.

-250 to +260

Fluolion® 02PTFE/inorganic filler

02 BlueSimilar properties to Fluolion® 01, but with improved wear resistance. -260 to +260

Fluolion® 03PTFE/carbon/graphite

03 BlackExcellent material for heat and wear resistance. Recommended for dry and poorly lubricated applications. Suitable for duties in water and steam.

-250 to +260

Fluolion® 05PTFE/carbon/graphite

05 Black

Similar to Fluolion® 03, but offers superior wear resistance. Excellent in steam and water under severe conditions. Very good extrusion resistance at high temperature. Excellent for back-up rings.

-250 to +260

Fluolion® 06PTFE/carbon/MoS2

06 Black

Excellent for extreme dynamic conditions, with combinations of high temperature, pressure, speed, and dry running. Excellent in water and water-based solutions. Abrasive when running against soft metal counterfaces.

-250 to +260

Fluolion® 07PTFE/bronze

07 BrownExcellent in reciprocating hydraulic applications: not recommended for rotary use. Good for high pressure applications. Good abrasion resistance.

-150 to +260

Fluolion® 08PTFE/polymer

08 Light brownSpecial grade for high temperature applications. Recommended for low to medium speed applications running against soft metals.

-240 to +260

Fluolion® 09PTFE/aromatic

polyester09 Brown

Special grade with superior heat and wear resistant characteristics. Non-abrasive; recommended for low to high speed applications running against soft metals. Not recommended for use in water.

-250 to +260

UHMWPE 10 WhiteExcellent low-wearing material, being highly abrasive resistant. This sturdy material offers limited heat and chemical resistance.

-250 to +80

Fluolion® 11PTFE/glass/MoS2

11 GreyIdeal for improved sealing at lower pressures. Can be abrasive when running against soft metal counterfaces. -250 to +260

Fluolion® 12PTFE/graphite

12 Black

General purpose grade with good heat and wear resistance. Good in water and non-lubricating fluids; compatible with all common hydraulic fluids and most chemicals.

-250 to +260

Unilion® seal jacket materials


Material nameand description

Jacketmaterial

codeColour Applications

Temperature range –

continuous use(°C)

PEEK 13 Light brownA high modulus material with excellent high temperature resistance. Used for anti-extrusion and other support rings.

-70 to +260

Fluolion® 15PTFE/inorganic filler

15 WhiteFood-compatible filled PTFE. Typically used for bearing/support ring duties. -250 to +260

Fluolion® 18PTFE/glass filler 18 Off-white

Higher modulus material ideal for anti-extrusion support rings. Can be abrasive when running against soft metal counterfaces.

-250 to +260

Fluolion® 22Modified PTFE

22 White Excellent for static and intermittent dynamic applications. Particularly good at cryogenic applications. Conforms to FDA requirements.

-260 to +260

Fluolion® 22CModified PTFE/25%

carbon22C Black

Similar to Fluolion® 22, but offers increased wear resistance. Excellent for extreme dynamic applications with combinations of high temperature, pressure, speed, and dry running.

-260 to +260

PCTFE 28 ColourlessHigh mechanical strength, chemical resistance and low shrinkage rate at low temperatures makes this material ideal for cryogenic applications.

-250 to +160

POM 30 WhiteThe combination of high strength and low coefficient of friction results in POM being perfectly suited as a material for bearings, bushes and guide bands.

-50 to +100

Other material compounds are available on request to meet specific applications, for example Norsok M-710 approved grades.

Unilion® seal spring materials


Unilion® spring-energised seals are available with a selectionof spring designs and materials. The materials are compatiblewith most media. Other spring materials are available, butminimum production quantities may be required. If necessary,please contact James Walker for advice regarding yourspecific applications – [email protected].

Springmaterial

code

Materialdescription Unilion®

TypesJ01 to J10

TypesJ20 to J29

TypesJ30 & J31

01 301 stainless steel Optional Standard

02 Corrosion resistant cobalt alloy

Standard Standard

Full specifications for these materials are available on request. Alternative alloys are available on request to meet specific applications, for example NACE approved grades.

Unilion® seal diameter details

Unilion® TypesJ01 to J08

Unilion® Types J09, J10 + J28, J29

Unilion® TypesJ20 to J27

Unilion® TypesJ30, J31

CrossSectionCode

Minimumrod

diameter

Minimumbore

diameter

CrossSectionCode

MinimumID

MinimumOD

CrossSectionCode

Minimumrod

diameter

Minimumbore

diameter

CrossSectionCode

MinimumID

MinimumOD

1 2 5 1 6 10 1 5 8 3 20 26

2 4 9 2 12 15 2 10 15 4 40 45

3 7 13 3 20 28 3 12 18 5 85 95

4 15 25 4 45 50 4 16 25 6 100 120

5 60 72 5 85 96 5 65 77 7 120 150

6 85 105 6 100 110 6 100 120 - - -

All dimensions in mmFor diameters outside the ranges quoted, please contact the James Walker Technical Support Team – [email protected].

Unilion® seal technical details


Unilion® is a spring-actuated and pressure-assisted sealing device comprising a thermoplastic jacket and a corrosion-resistant metal spring. When the Unilion is seated in a gland, the spring will be in compression forcing the jacket against the hardware. The spring compensates for jacket wear and eccentricity. The system pressure assists the spring pressure.

The spring load can be tailored to meet special low friction requirements in dynamic applications, and loading can be increased for cryogenic sealing duties where thermal contraction of the seal may be an issue.

Temperature, pressure and extrusion gap

Material

L0 width

Pure PTFE 0.10 0.07 0.05 -

Filled PTFE 0.15 0.10 0.07 -

L1 width

Pure PTFE 0.15 0.10 0.07 -

Filled PTFE 0.20 0.15 0.10 0.07

L2 width

Filled back-up 0.20 0.15 0.10 0.07

PEEK back-up 0.20 0.15 0.10 0.07

L2 width

Filled back-up 0.25 0.20 0.15 0.10

PEEK back-up 0.35 0.25 0.20 0.15

All dimensions in mmIf application conditions fall outside the specified range, please contact the James Walker Technical Support Team – [email protected].

Maximum recommended diametral extrusion gap

When sealing at high pressure and/or high temperature, the clearance between the hardware ‘extrusion gap’ becomes highly significant. In these conditions, the jacket material can extrude into the gap causing premature sealing failure. The extrusion gap should be held to the minimum practical and ideally should not exceed the values shown above. For these reasons the anti-extrusion rings are manufactured of a harder material than the seal jackets.

Fluid beingsealed

Surface finishDynamic surface Static surface

Cryogenics 0.05 to 0.2 Ra 0.1 to 0.2 Ra

Helium gasHydrogen gas

0.05 to 0.2 Ra 0.15 to 0.3 Ra

AirNitrogen gasArgon gasNatural gasPetrol

0.15 to 0.4 Ra 0.3 to 0.8 Ra

WaterHydraulic fluidCrude oilGreases

0.2 to 0.4 Ra 0.4 to 1.6 Ra

All dimensions in µm

Surface finishes and hardness

Dynamic sealingThe quality of the surface finish influences the relative wear of the jacket material. The transfer of a thin film of PTFE from the seal jacket to the mating dynamic surface will improve seal life. Relatively rough finishes wear the jacket material too rapidly, whereas smooth surfaces can result in insufficient material transfer to form the thin film. As a general rule, the higher the sealing surface hardness the better the seal performance. Greater hardness reduces wear and increases seal life. A 40 HRC or higher value is recommended for slow to moderate movements. Ensure that the seal’s counterfaces are free from scores and spiral machining marks.

Static sealingEnsure that the seal’s counterfaces are free from scores andspiral machining marks.

Graph for guidance only

70 / 700

60 / 600

50 / 500

40 / 400

30 / 300

20 / 200

10 / 100

0-100 -50 0 50 100 150 200 250

MPa / bar

Temperature °C

Unilion® types J01 to J10


Standard profiles

Radial seals

Type Features Type

Unilion®

J01

Radial seal for static and dynamic duties; suitable as rod or piston seal.Medium to high spring load for positive sealing, but with some friction.Suitable for service with medium to high system pressure.Type J01: Standard profileType J02: As J01, but with extended heel for higher pressure service.

Unilion®

J02

Unilion®

J03

As Type J01, but for reciprocating action only.Contains scraper lip on inside diameter.Type J03: Standard profile.Type J04: As J03, but with extended heel for higher pressure service.

Unilion®

J04

Unilion®

J05

As Type J01, but for reciprocating action only.Contains scraper lip on outside diameter.Type J05: Standard profile.Type J06: As J05, but with extended heel for higher pressure service.

Unilion®

J06

Radial flange seals

Unilion®

J07

As Type J01, but has flange that is clamped to prevent undesirable movement of the seal.Rotation can occur with standard designs, due to thermal expansion.

Unilion®

J08

As Types J01 and J07, but for reciprocating action only.Contains scraper lip on inside diameter.

Axial seals

Unilion®

J09Axial seal for static applications as in Type J01.Used as an internal face seal.

Unilion®

J10Axial seal for static applications as in Type J01.Used as an external face seal.


Unilion® types J20 to J29

Standard profiles

Radial seals

Type Features Type

Unilion®

J20

Radial seal for dynamic duties as rod or piston seal.Low spring load and high deflection provides low friction sealing and compensates for minor eccentricity or misalignment.Suitable for service with low to medium system pressure and/or speed. Type J20: Standard profile.Type J21: As J20, but with extended heel for higher pressure service.

Unilion®

J21

Unilion®

J22

As Type J20, but for reciprocating action only.Contains scraper lip on inside diameter.Type J22: Standard profile.Type J23: As J22, but with extended heel for higher pressure service.

Unilion®

J23

Unilion®

J24

As Type J20, but for reciprocating action only.Contains scraper lip on outside diameter.Type J24: Standard profile.Type J25: As J24, but with extended heel for higher pressure service.

Unilion®

J25

Radial flange seals

Unilion®

J26

As Type J20, but has flange that is clamped to prevent the seal rotating with the shaft.Rotation can occur with standard designs, due to thermal expansion and other effects with dynamic applications.

Unilion®

J27

As Types J20 and J26, but for reciprocating action only.Contains scraper lip on inside diameter.

Axial seals

Unilion®

J28Axial seal for static or dynamic applications as in Type J20.Used as an internal face seal.

Unilion®

J29Axial seal for static or dynamic applications as in Type J20.Used as an external face seal.

To order or get further details, call your local contact shown on rear cover or listed at www.jameswalker.biz10 To order or get further details, call your local contact shown on rear cover or listed at www.jameswalker.biz10

Unilion® types J30 & J31

Standard profiles

Our axial face seals Unilion® Type J30 and J31 contain a heavy duty, higher load spring.We recommend these seals for extreme static sealing conditions.

How to order/specify your Unilion® sealPlease follow the Order example as shown below, and quote your equivalent of the seal designation:J02 3 1 -01250- 03 02

Note that maximum temperature, pressure and speed ratings may not be applied simultaneously. Please consult the James Walker Technical Support Team ([email protected].)for recommendations, particularly where applications are close to the recommended performance limits.

Axial seal for internal pressure: Unilion® J30 Axial seal for external pressure: Unilion® J31

C r osssection

Nr

C0.15

ENOM

F0.05

H T1 T2 J0.15

KMi n

L+0.3-0.0

L1+0.3-0.0

L2+0.3-0.0

L3Mi n

1 3.4 0.10 0.40 1.42/1.47 0.05 0.13 0.8 3.5 2.4 3.8 5.3 2.42 4.3 0.13 0.58 2.26/2.31 0.05 0.13 0.9 4.5 3.6 4.6 6.2 3.63 5.5 0.15 0.70 3.07/3.12 0.05 0.15 1.3 6.0 4.8 6.0 7.7 4.84 8.5 0.18 0.80 4.72/4.78 0.06 0.15 1.8 7.5 7.1 8.5 10.8 7.15 11.5 0.20 1.20 6.05/6.12 0.07 0.20 2.3 8.5 9.5 12.1 14.7 9.56 15.5 0.24 1.6 9.35/9.40 0.08 0.25 3.3 10.0 13.5 15.0 18.0 13.5

Order example

Product type

Cross section code

Hardware indicator 0 = Axial seal 1 = Radial shaft seal 2 = Radial piston seal

Hardware diameter (eg, 125.0 mm)

Seal jacket material

Spring material

20°

L0L1L2

L0L1L2

Har dware Design

L 1

J

25°

B + 2C

C

BRod+0.0-T 1

B Rod+0.0 -T 1

A

(B+ 2H) - 0.0 +T1

20°

20°

K MIN

E/ 2

20

K MIN

B(A - 2H ) +0.0 -T 1

H

APiston +T

-0.0

H

R od or shaft seal with �ange R od seal Pi ston seal

L3

A dia +T 2-0.0

L3

B dia +0.0- T 2

H

Axial seal inside face A xial seal outside face

7

J02 3 1 01250 03 02

F

- -

Note: please specify OD for J30, and ID for J31.

Unilion® back-up rings


Solid back-up rings

Back-up rings are used in combination with axial and radial seals when the extrusion gap is too large for the required pressure and temperature.Please refer to page 7 for information on the use of these back-up rings (L2 width).

For further information, please contact the James Walker Technical Support Team – [email protected].

Bespoke productsIf a bespoke sealing solution is required, please contact the James Walker Technical Support Team – [email protected].

Hardware design — Rod sealing


Unilion® TypesJ01, J02, J03, J04, J05, J06 + J20, J21, J22, J23, J24, J25

Cross SectionCode

H ØA (B + 2H)

T1 K Min L0+0.30 -0.00

L1+0.30-0.00

L2+0.30 -0.00

1 1.42 B + 2.84 0.05 3.50 2.40 3.80 5.30

2 2.26 B + 4.52 0.05 4.50 3.60 4.60 6.20

3 3.07 B + 6.14 0.05 6.00 4.80 6.00 7.70

4 4.72 B + 9.44 0.06 7.50 7.10 8.50 10.80

5 6.05 B + 12.10 0.07 8.50 9.50 12.10 14.70

6 9.35 B + 18.70 0.08 10.00 13.50 15.00 18.00

All dimensions in mm

L0L1L2

ØA(B+2H)+T1/-0.0 ØB

Rod+0.0/-T1

Hardware design — Piston sealing


Unilion® TypesJ01, J02, J03, J04, J05, J06 + J20, J21, J22, J23, J24, J25

Cross SectionCode

H ØA (A - 2H)

T1 K Min L0+0.30 -0.00

L1+0.30-0.00

L2+0.30 -0.00

1 1.42 A - 2.84 0.05 3.50 2.40 3.80 5.30

2 2.26 A - 4.52 0.05 4.50 3.60 4.60 6.20

3 3.07 A - 6.14 0.05 6.00 4.80 6.00 7.70

4 4.72 A - 9.44 0.06 7.50 7.10 8.50 10.80

5 6.05 A - 12.10 0.07 8.50 9.50 12.10 14.70

6 9.35 A - 18.70 0.08 10.00 13.50 15.00 18.00


L0L1L2

ØB (A-2H)

+0.0/-T1

ØACylinder+T1/-0.0


Hardware design — Rod or shaft sealing with flange

Unilion® TypesJ07, J08 + J26, J27

Cross SectionCode

C(±0.15)

H ØA (B + 2H)

T1 J(±0.15)

K Min L1+0.30 -0.00

1 3.40 1.42 B + 2.84 0.05 0.80 3.50 3.80

2 4.30 2.26 B + 4.52 0.05 0.90 4.50 4.60

3 5.50 3.07 B + 6.14 0.05 1.30 6.00 6.00

4 8.50 4.72 B + 9.44 0.06 1.80 7.50 8.50

5 11.50 6.05 B + 12.10 0.07 2.30 8.50 12.10

6 15.50 9.35 B + 18.70 0.08 3.30 10.00 15.00


L1

ØB Rod

+0.0/-T1

ØA (B+2H)+T1/-0.0


Hardware design — Axial sealing

Unilion® TypesJ09, J10 + J28, J29

Cross SectionCode

H T1 T2 L3 +0.30 -0.00

1 1.42 0.05 0.13 2.40

2 2.26 0.05 0.13 3.60

3 3.07 0.05 0.15 4.80

4 4.72 0.06 0.15 7.10

5 6.05 0.07 0.20 9.50

6 9.35 0.08 0.20 13.50


Unilion® TypesJ30, J31

Cross SectionCode

H T1 T2 L3 +0.30 -0.00

3 3.07 0.05 0.15 4.80

4 4.72 0.06 0.15 7.10

5 6.05 0.07 0.20 9.50

6 9.35 0.08 0.25 13.50

7 12.40 0.08 0.30 16.50


A DIA +T2/-0.0 B DIA +0.0/-T2

H+T1/-0.0

Appendix 1: Unilion® Fitting Guide


Unilion® — spring-energised PTFE/plastic lip seals.

Fitting techniques should be considered at the design stage of any equipment using spring-energised PTFE lip seals. They cannot be stretched or squeezed into position as easily as elastomeric seals.

Please read these instructions before starting to fit the seal

Check the seal and seal housing. Ensure that the seal is suitable for the operating parameters of the equipment, and that the seal and housing are the correct sizes.

For Health & Safety reasons, shut down the fluid handling system before installing your new seal. Please wear all required PPE to ensure a safe working environment.

Remove old seal, and thoroughly clean the seal housing and lead-on/lead-in surfaces where seal must pass during installation.

Always install a Unilion® with its open face towards the pressure media to be retained

Split-type housingsFor high-integrity sealing and cryogenic applications, we always recommend the use of a split housing, as it virtually eliminates the need to distort the Unilion during installation.

Expose the seal housing cavity by removing the gland follower or retaining plate. Insert the seal fully into the exposed cavity, with the seal's open face towards the system pressure.

Ensure the seal is evenly seated around the entire circumference. Replace the gland follower or retaining plate, and carefully reassemble the equipment.

A 20° to 30° lead-on/lead-in chamfer is required to ensure that the seal is not damaged when passing the cylinder/bore entrance, or piston head/shaft end.

Take care not to damage or permanently distort the PTFE/plastic element during installation.


Unilion® — spring-energised PTFE/plastic lip seals.

Fitting techniques should be considered at the design stage of any equipment using spring-energised PTFE lip seals. They cannot be stretched or squeezed into position as easily as elastomeric seals.

Please read these instructions before starting to fit the seal

Check the seal and seal housing. Ensure that the seal is suitable for the operating parameters of the equipment, and that the seal and housing are the correct sizes.

For Health & Safety reasons, shut down the fluid handling system before installing your new seal. Please wear all required PPE to ensure a safe working environment.

Remove old seal, and thoroughly clean the seal housing and lead-on/lead-in surfaces where seal must pass during installation.

Always install a Unilion® with its open face towards the pressure media to be retained

Split-type housingsFor high-integrity sealing and cryogenic applications, we always recommend the use of a split housing, as it virtually eliminates the need to distort the Unilion during installation.

Expose the seal housing cavity by removing the gland follower or retaining plate. Insert the seal fully into the exposed cavity, with the seal's open face towards the system pressure.

Ensure the seal is evenly seated around the entire circumference. Replace the gland follower or retaining plate, and carefully reassemble the equipment.

A 20° to 30° lead-on/lead-in chamfer is required to ensure that the seal is not damaged when passing the cylinder/bore entrance, or piston head/shaft end.

Take care not to damage or permanently distort the PTFE/plastic element during installation.

Piston with partially enclosed housing

A

15°

Use this method only when the inside diameter of the seal is at least 25 times its nominal radial section.

If you require advice on fitting a Unilion® seal in this housing configuration, please contact the James WalkerTechnical Support Team – [email protected].

This operation requires a 15° lead-on chamfer to the housing groove from the pressure side of the system. A locking lip of A/4 is needed to ensure the seal seats securely (where A is the nominal radial section of the seal).

To install the seal, gently feed it up the chamfer, with the seal's open face towards the system pressure. Then swiftly press it over the locking lip and into the housing groove, thus minimising any distortion.

A A/4

15°

Partially enclosed cylinder housingUse this method only when the inside diameter of the seal is at least 10 times its nominal radial section.

If you require advice on fitting a Unilion® seal in this housing configuration, please contact the James WalkerTechnical Support Team – [email protected].

This operation requires a 15° lead-in chamfer to the housing groove from the pressure side of the system. A locking lip of A/4 is needed to ensure the seal seats securely (where A is the nominal radial section of the seal).

To install the seal, distort it slightly into an ellipse and insert it into the bore, with the seal's open face towards the system pressure. When the back of one quadrant of the seal is located firmly in the housing, feed the remainder of the seal down the 15° lead-in and into the housing.

Safety Data Sheets (SDS) are available on request

Jaeger Seals NV, Kanaalstraat 200, B3971 Heppen, BelgiumTel: +32 (0)11 393154. Fax: +32 (0)11 393155. Email: [email protected]

Health warning: If PTFE products are heated to elevated temperatures, fumes will be produced which may give unpleasant effects, if inhaled. Whilst some fumes are emitted below 300°C from PTFE, the effect at these temperatures is negligible. Care should be taken to avoid contaminating tobacco with particles of PTFE or PTFE dispersion, which may remain on hands or clothing.

Information in this publication and otherwise supplied to users is based on our general experience and is given in good faith, but because of factors which are outside our knowledge and control and affect the use of products, no warranty is given or is to be implied with respect to such information. Unless governed by type approval or contract, specifications are subject to change without notice. Statements of operating limits quoted in this publication are not an indication that these values can be applied simultaneously.

To ensure you are working with the very latest product specifications, please consult the relevant section of the James Walker website: www.jameswalker.bizCPC: UniSeal Level 19 AM10 GB07 26112014

Unilion® — spring-energised PTFE/plastic seals.

A/4


Appendix 2: Engineering in Fluolion® PTFE

Polytetrafluoroethylene (PTFE) is a remarkable engineering material that was discovered in 1938 by DuPont (USA) and given the trade name Teflon®. Fluolion® is the registered trade name for PTFE compounds and material products manufactured to exacting standards by James Walker.

Fluolion PTFE has many outstanding physical, chemical and electrical properties that make it invaluable to industry today:

• Resistance to virtually every known chemical and solvent. Only molten alkali metals, fluorine and some fluorine compounds at elevated temperature will attack it.

• Lowest coefficient of friction for a solid engineering material.• Extremely high electrical resistance.• High dielectric strength.• Low dielectric constant over a wide frequency range.• Extremely wide temperature tolerance: -250°C to over

+300°C depending on application circumstances.• Ease of machining.• Does not support combustion or spread of flame.• Excellent weatherability: does not degrade under UV radiation.• No chemical swell when subjected to moisture or fluids.• Moderate cost.

Operational properties

Although the properties of pure PTFE are generally excellent, they can be improved or modified to meet specific operating conditions by the addition of fillers at the raw material stage.By this means PTFE can be given:

• Improved creep resistance.• Increased surface hardness.• Reduced frictional wear.• Increased rigidity.• Increased thermal conductivity.• Increased thermal dimensional stability.• Increased electrical conductivity.

Fillers include the following in varying percentages by weight:

• Glass fibre• Bronze• Graphite and/or carbon• Molybdenum disulphide (MoS2)• Ceramics and mineral oxides• Other additives to meet specific requirements.

Filler content is typically between 5% and 40% by weight. Below 5% the effect of the filler is usually insignificant. Above 40% the physical properties of the base material are likely to be impaired, except with very high density fillers.

Manufacturing techniques

Fluolion products are manufactured from prime grades of raw materials obtained from major international suppliers.

In its unprocessed state PTFE is a granular fine powder. Fillers are added and combined intimately with the powder when particular properties need modification. This is usually carried out on the raw materials by suppliers.

MouldingTo manufacture solid PTFE, a precisely metered quantity of the pure or filled powder is compressed to the desired shape and preformed using a technique similar to that for shaping powdered metals.

During this procedure the powder compacts to between one-half and one-fifth of its original volume.

As PTFE has no liquid state – it passes from crystalline solid to amorphous gel at 327°C – it cannot be injection moulded like most polymers. It must therefore be moulded within the bounds of powder technology where no fluid pressure transfer characteristics exist.

After preforming, the compacted dry powder resembles a stick of chalk: brittle and with little cohesion or strength.

The moulded powder material is then sintered in an oven atbetween 360°C and 380°C – well into its amorphous state – where the granules coalesce. The material is cooled slowly toa hard, tough stress-relieved crystalline solid.

The shapes can be:

• Finished mouldings.

• Blanks for machining.

• Stock bar, tube or sheet.

Outstanding properties

F

C


Machining

Solid PTFE is an excellent material to process further. It is safe and easy to machine using common metal-cutting techniques such as:

• Turning• Milling• Shaping• Stamping, etc.

Temperature control is critical when working with PTFE with extreme accuracy. Like many polymers, PTFE has a high coefficient of thermal expansion. But, in addition, this material experiences a step in its thermal expansion at 19°C when the molecular fluorocarbon chain straightens slightly in its helical form. This typically increases volume by about 1.3%.

This expansion phenomenon makes it necessary to machine PTFE at 23°C or above. Allowances must therefore be made for dimensional differences between machining temperature and final operating temperature of the Unilion® seal.

We maintain strict temperature control during machining and subsequent inspection to ensure the dimensional integrity of our Fluolion® components.

Other polymeric materials

Our experience is not confined to PTFE. We also work with: FEP (fluorinated ethylene-propylene), PFA (perfluoroalkoxy alkanes), PCTFE (polychlorotrifluoroethylene), PVFDF/PVF (polyvinylidene fluoride), UHMWPE (ultra high molecular weight polyethylene), PEEK (polyetheretherketone), PES (polyether-sulphone), polyacetals, polyamides (nylons), and polyimides.

1. Mould filled PTFE polymer in one shot

4. Compacted crystalline PTFE powder (preform) removed from mould

6. Programme-cooled to ambient temperature. Now 2-3% smaller than preform

7. To machine shop as fully stress-relieved billet for precision manufacture of Unilion® seal jackets

5. Programme-sintered in an oven at 360°C in free state. Now an amorphous gel (approximately 23% larger when cold)

2. Pressure applied, between 15-75 MN/m2 depending on polymer type

3. Additional compaction from both ends

PTFE moulding


Unilion® enquiry form

Customer name

Contact

Contact email Contact phone

Project

Application/Hardware

Motion

❑ Static ❑ Reciprocating ❑ Rotary ❑ Oscillating

❑ Internal pressure ❑ External pressure ❑ Back pressure – is BP ring required?

Operating parameters

Media to be sealed

Units Minimum Maximum Operating Test

Temperature

Pressure

Stroke length (reciprocating)

Cycle rate

Degree of arc (oscillating)

Velocity

Vacuum


❑ Rod

❑ Other rod

❑ Face seal

❑ Piston

❑ Other piston

Units Minimum Maximum

A Diameter

B Diameter

C Diameter

D Groove width / depth

E Extrusion gap

F Step height

Surface finish (Ra)

Technical guides


Gaskets & Jointings Guide


Issue 8

• Sheet jointings & soft cut gaskets

• Spiral wound gaskets

• Kammprofile gaskets

• API/ASME ring joints

• Machined metal gaskets

• Complementary products

Gasket & jointings

High Performance Sealing for all Marine Applications


Global supply of: • Gaskets & jointings• Packings & tank lid seals• Expansion joints & bellows• Rotary & hydraulic seals• Pipe supports & much more…

Issue 34

Marine industry

Designed &

produced by designbrand ltd Tel: 0845 0559216 ww

w.designbrand.co.uk

POWER GENERATION

OIL & GAS

CHEMICAL PROCESSING

TRANSPORT

assuring bolted joint integrity

RotaBolt® tension control

Improving valve sealing performance & emissions control


Issue 3

Valve sealing guide

Elastomer Engineering Guide

Elastomer engineering

Compression Packings Guide


The comprehensive guide to compression packings for• Pumps• Valves • Hatch lids• Crucible lids• Furnace doors• Gland sealing duties

Issue 9

Compression packings

‘O’ Ring Guide


The comprehensive guide to ‘O’ ringsealing systems including• ‘O’ ring selection• General & high performance materials• Housing design & tolerances• Cords, kits & lubricants

Issue 7

‘O’ Rings

Sealing Guide for the Iron & Steel Industry


Global supply of ● Best-value fluid seals & gaskets● Standard & custom-designed products● Bolting technology● Vibration damping & control

Issue 3

Iron & steel industry guide

Sealing Guide for Conventional Thermal Power Generation


Issue 3

Global supply of

• Best-value fluid seals & gaskets• Standard & custom-designed products• Expansion joints & bellows• Bolting technology• Vibration damping & control

Conventional power generation

Hydraulic Sealing Guide


• Rod/glandseals• Pistonseals• Wipers&scrapers• Bearingstrips• ‘O’rings

Issue 28.5

Hydraulic seals

Expansion joints & bellows

Sealing in the Nuclear Power sector


Issue 1.3

• World class materials & sealing products

• Custom designed & manufactured

• Fully researched, developed & tested

• With nuclear standards & certifications

• Global support to OEMs, contractors & utilities

Nuclear power generation

These guides give detailed information on many of the sealing products and services supplied by James Walker. Please ask for your copies, or visit our website www.jameswalker.biz where many of them can be downloaded in pdf format.


General Information

Health warning: If PTFE products are heated to elevated temperatures, fumes will be produced which may give unpleasant effects, if inhaled. Whilst some fumes are emitted below 300°C from PTFE, the effect at these temperatures is negligible. Care should be taken to avoid contaminating tobacco with particles of PTFE or with PTFE dispersion, which may remain on hands or clothing. Safety Data Sheets (SDS) are available on request.

Information in this publication and otherwise supplied to users is based on our general experience and is given in good faith, but because of factors which are outside our knowledge and control and affect the use of products, no warranty is given or is to be implied with respect to such information. Unless governed by type approval or contract, specifications are subject to change without notice. Statements of operating limits quoted in this publication are not an indication that these values can be applied simultaneously.

To ensure you are working with the very latest product specifications, please consult the relevant section of the James Walker website: www.jameswalker.biz.

Environmental statement: This document is manufactured using advanced environmentally friendly technologies and follows the strict environmental standard BS EN ISO 14001. Made from chlorine-free pulp (ECF) with post-consumer recycled fibre obtained from sustainable wood forests, and printed using vegetable based inks, by Binfield Printers Ltd. For those who wish to reduce further their impact on the environment, this publication is also available as a PDF from: www.jameswalker.biz.

James Walker Sealing Products & Services LtdRegistered Office: Lion House, Oriental Road, Woking, Surrey GU22 8AP, United Kingdom. Reg no: 00264191 England

© James Walker 2016

BP4659 1016/1mPIIL2927319

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