Merkel PTFE U-rings. for high level applications

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1 Merkel PTFE U-rings for high level applications Product information Merkel PTFE U-rings

2 Simrit, Your Global Technology Specialist for Seals and Vibration Control Simrit, Your Global Technology Specialist for Seals and Vibration Control offers you a complete service package. A unique range of products and services guarantees you numerous advantages over the competition. Simrit acts as a partner to general industry. Its position as a market leader is achieved through continuous research, development and manufacture. We have the world s widest range of seals and vibration control products, and can offer you solutions based on the demands of state-of-the-art-technology, solutions which set standards. This way we secure competitive advantages for you based on experience all around the world: Simrit has a presence throughout Europe, America and Asia, either directly or through its affiliated companies NOK (Japan) or Freudenberg-NOK (USA). The transfer of knowledge between these markets is incorporated directly into the Simrit service package. With our many Simrit Service Centres and Simrit distribution Partners, we serve and supply more than 100,000 customers worldwide. Our Simrit Partners ensure rapid availability from stock. This means spare parts quickly arrive when and where they are needed. There is a Simrit Partner near you as well. Make the most of Simrit s service package and give yourself a real competitive edge: Constant innovations Uniquely wide range of products Strong product brands Unique materials expertise A wide range of value added services Simrit offers a complete package of products and services, including leading brands such as Simmerring, Merkel, Integral Accumulator, Lederer and ISC O-Ring. Vibration Control Special Sealing Products: Bellows, Diaphragms, Elastomer Composite Parts and Precision Mouldings Lederer Liquid Silicone Products ISC O-Ring Integral Accumulator Merkel Hydraulics / Pneumatics Simmerring 2

3 Merkel PTFE U-rings, practical in a wide range of applications PTFE U-rings are designed to be pressurised from one side. A metal spring acts as a pre-load component of the sealing lips and prevents the loss of contact pressure due to thermal expansion. In operation the pre-load of the metal spring is overridden by the system pressure. Benefits of Merkel PTFE U-rings Smaller housing space Variants available for high pressures and vacuum; optimised versions for lifting, rotary and pivoting motion and for static applications Universal chemical resistance due to PTFE basic materials and springs made of non-rust CrNi steel Wide temperature range Good dry-running characteristics possible thanks to application specific selection of most suitable PTFE compounds Spring variants with different spring characteristic curves influence the friction force at the sealing lip. No occurrence of stick-slip Resistance to ageing High functional reliability due to the permanent elasticity of the metal spring Examples of use Valve engineering General chemicals Mechanical engineering Food processing industry Pharmaceuticals Petrochemicals e.g.: ball valves, flanges/lids, screwed connections, rotary joints and distributors, hot water and steam valves, valve spigots, control shafts, reciprocating pumps, mounts Delivery forms PTFE U-rings are supplied with three different types of spring: V-spring Bridges gap and tolerances with relatively large spring displacement Soft spring characteristic curves for minimum friction forces Dimensions permit usage in O-Ring housings (without NRVD-9489) Can be used in U-rings for dynamic and static applications U-ring versions for radial/axial direction of action, also available as rotary seals Special version with protected spring Spring force Round spring High spring force with relatively low spring displacement A special U-ring design distributes the force over several sealing lips Can be used in U-rings for dynamic and static applications U-ring versions for radial/axial direction of action U-spring Bridges sizeable gaps and bearing play with increased spring rate in conjunction with relatively large spring displacement Can be used in U-rings for dynamic and static applications Version with protected spring (NRVR-9499) Maximum resistance to media and sterile spring version provides for sole usage between axial sealing surfaces (flanges, lids, rotary joints) Types of spring and their characteristic curves (diagram) Spring displacement 3

4 Delivery forms If universal resistance to media is not a priority, O-Rings made of elastomer materials can be used in place of metal springs. Use with high pressures and/or a large gap behind the seal at the same time makes it necessary to use back-up rings with a special geometry for the application. The version with a metal locking ring is often chosen to produce housings with relatively little effort. When using the U-ring version for rotation, the locking ring is the most reliable way of preventing twisting. The correct sealing type as a function of the installation situation Version Pressure direction axial Pressure direction radial V-spring Round U-spring V-spring Round U-spring spring spring Dynamic sealing NRVI-9492 NRVD-9489 lip inside (rod) NRRI-9442 Dynamic sealing NRVA-9490 NRRA-9474 lip outside (piston) Seal open inwards NRVR-9494 NRRR-9459 NRVR-9486 (pressure mode) NRVR-9499 Seal open outwards NRVR-9493 NRRR-9485 NRVR-9487 (vacuum) The correct sealing type as a function of the installation situation Version Covers/ Rotating Rotating Journals flanges and swiveling joints and spindles movements NRVA-9490 NRVR-9494 V-spring NRVR-9493 NRVD-9489 NRVI-9492 NRRA-9474 NRRR-9459 Round spring NRRR-9485 NRRI-9442 NRVR-9487 U-spring NRVR-9486 NRVR-9499 = very well suited = well suited 4

Standard materials of Merkel U-rings PTFE, pure PTFE-pure, modified PTFE/glass fibre PTFE/carbon PTFE/carbon fibre PTFE/glass/molybdenum PTFE/Ekonol PTFE/aramide UHMW PE (polyethylene) PEEK Spring

5 Standard materials of Merkel U-rings PTFE, pure PTFE-pure, modified PTFE/glass fibre PTFE/carbon PTFE/carbon fibre PTFE/glass/molybdenum PTFE/Ekonol PTFE/aramide UHMW PE (polyethylene) PEEK Spring materials (AISI 301) (Elgiloy) For our PTFE products only uncut materials are used as semi finished products. This means that the mechanical loading capacity is not impaired by the addition of PTFE ground material that has already been sintered. Virtually all compounds are also available on the basis of modified PTFE. Benefits can be seen in an improved incorporation of fillers and thus also further improvement in the mechanical loading capacity as well as the reduced diffusion of media along the filler surfaces. Duty Limits Pressure Temperature Sliding speed Dynamic Static Oscillating Rotating < 45 MPa < 120 MPa -200 to 260 C < 10 m/s < 2.5 m/s Surface Quality Roughness depth R a Sealing surfaces, dynamic/static see diagram Lead-in bevels* < 1.6 µm Groove edge* < 2.5 µm * Rounded edges burr-free For dynamic sealing the aim is surfaces with a high percentage contact area (tpi 50-90% with 50% cutting depth Rz/2). From 25 MPa (depending on the gap width, temperature, pressure, material) or also with gaps caused by the expansion of components it may be necessary to use back-up rings. When considering the operating parameters listed, please bear in mind that they stand in relation to each other and represent maximum values. Please agree the type of seal and permissible maximum values with us in relation to your application. Average roughness height Ra of the sealing surface Ra max Hydrogen Steam Air motor oils SAE Water Grease Bitumen Dust Granules static dynamic gaseous liquid solid State of aggregation of the medium Achievable surface quality as a function of production process, see DIN

Contact area hardness HRC 20-65 The hardness of the contact area is a key factor for the functionality of the seal.

A minimum hardness penetration depth, (see installation data) of 300 µm should be observed.

6 Contact area hardness HRC The hardness of the contact area is a key factor for the functionality of the seal. For many applications standard constructional, tempering and hardened steel also offer a sufficient level of surface hardness. A minimum hardness penetration depth, (see installation data) of 300 µm should be observed. Otherwise a relatively soft shaft material may give way under the hardening layer, something which may quickly destroy a seal. In principle, the hardest material that is practical in technical terms should be used. Housing tolerances See article lists Fitting instructions Installation preferably in axially accessible grooves. If clipping or snapping in position is necessary, e.g. in half-enclosed housings, please consult our application engineers. Please remember rods and housings should be installed at an angle. Please avoid sharp edges. Lightly oil components before fitting. Housings must be clean and free of foreign bodies. The dependence on the following items should also be borne in mind: type of movement running speed media (lubricating, abrasive, dry running) sealing material (hard, soft) temperature pressure 6

7 U-rings with V-shaped spring Dimensional recommendation U-ring NRVI-9492 Standard material PTFE-carbon Spring material (AISI 301). Sealing lip inside, dimensions can be replaced by O-Rings as per AS 568A, installation identical to MIL-5514 Range of dimensions d available S H L C from to > >1.0 > >1.2 > >1.5 > >2.0 The following dimensional recommendations are in addition to our article lists. They are used when the article lists do not contain suitable sizes. 7

8 Article list U-ring NRVI-9492 Article No. d D S H L PTFE-carbon/

Dimensional recommendation U-ring NRVA-9490 Standard material PTFE-carbon Spring material 1.4310 (AISI 301).

9 Dimensional recommendation U-ring NRVA-9490 Standard material PTFE-carbon Spring material (AISI 301). Sealing lip outside Dimensions can be replaced by O-Rings as per AS 568A, installation identical to MIL-5514 Range of dimensions D available S H L C from to > > > >

10 Article list U-ring NRVA-9490 Artcle No. D d S H L PTFE-carbon/

11 Dimensional recommendation U-ring NRVR-9494 Range of dimensions d available B L S from to Dimensional recommendation U-ring NRVR-9493 Range of dimensions d available B L S from to

12 Dimensional recommendation U-ring NRVD-9489 Range of dimensions d available S H D 4 L 2 L 3-0,1 C from to d > d > d

13 U-rings with U-spring Dimensional recommendation U-ring 9487 Available dimensional range Range of dimensions d available B L* S from to from to B B B B+1.0 * medium heights should be preferably used Dimensional recommendation U-ring NRVR9486 and U-ring NRVR-9499 Range of dimensions D available B L* S from to from to B B B B+1.0 * medium heights should be preferably used 13

14 U-rings with round spring Dimensional recommendation U-ring NRRI-9442 Standard material PTFE-carbon and PTFE/glass/MoS2 Spring material (AISI 301). Sealing lip inside, dimensions suitable for housings as per DIN ISO 5597 (rod seal) Range of dimensions d available S H L C from to * > * > * > > > > > > >6 * with a profile dimension > 5 mm one sealing edge The following dimensional recommendations are in addition to our article lists. They are used when the article lists do not contain suitable sizes. 14

15 Article list U-ring NRRI-9442 Article No. d D S H L PTFE/glass/ PTFE-carbon/ MoS2/

16 Dimensional recommendation U-ring NRRA-9474 Range of dimensions D available S H L C from to * > * > * > > > > > > >6 * with a profile dimension > 5 mm one sealing edge Article list U-ring NRRA-9474 Article No. d D S H L PTFE-glass/ PTFE-carbon MoS2/

17 Dimensional recommendation U-ring NRRR-9459 Standard material PTFE-carbon and PTFE/glass/MoS2 Spring material (AISI 301). Sealing lip outside, dimensions suitable for housings as per DIN ISO 5597 (piston seal) Range of dimensions D available B L S from to Dimensional recommendation U-ring NRRR-9485 Range of dimensions d available B L S from to

From a standard design to an individual solution The standard models described above cover the requirements made on seals in the case of most applications.

18 From a standard design to an individual solution The standard models described above cover the requirements made on seals in the case of most applications. However, there are other applications which call for a customised solution. This may involve a requirement for increased performance in terms of dynamic properties and functional reliability with frequently recurring thermal loads with high temperature gradients. Product optimisation and the simplification of components may be necessary with one or more operating parameters. Examples of requirements requirement for simplified design of housings no additional measures involving prevention of twisting or fixing constant heat influence in temperature range from C special requirements on PTFE turned part in cooling phase and during downtimes Solution involving integrated functional elements Consideration of the functional elements of a rotary shaft seal and combination with the functional elements of a U-ring offer the following solution in line with the requirements: PTFE U-ring with optimised sealing lip geometry for rotation Metal spring for constant contact pressure of the sealing lip on the surface of the shaft, in particular to compensate for expansion caused by heat. Fixing, prevention of twisting and sealing from the housing by use of clamping ring technology. Benefits resulting from the development of seals in line with these requirements high functional reliability universal chemical resistance cost benefit regarding design of housing simplified storage due to standardisation of range Whether tried and tested standard versions or individual sealing solutions optimised according to the application; we have the right solution for every application. 18

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Product information Merkel PTFE U-rings Simrit, Your Global Technology Specialist for Seals and Vibration Control Simrit Services Your Benefits Constant innovations Technological edge Uniquely wide

20 Product information Merkel PTFE U-rings Simrit, Your Global Technology Specialist for Seals and Vibration Control Simrit Services Your Benefits Constant innovations Technological edge Uniquely wide range of products All from one source Strong product brands Specialised technological expertise Unique materials expertise Longer unit service life A wide range of value added services Competitive advantages, efficiency and lower costs e.g. Merkel PTFE U-rings for high level applications Your Benefits Smaller housing space Wide temperature range No stick-slip Vibration Control Special Sealing Products: Bellows, Diaphragms, Elastomer Composite Parts and Precision Mouldings Lederer Liquid Silicone Products ISC O-Ring Integral Accumulator Merkel Hydraulics / Pneumatics Simmerring Headquarters Europe: Freudenberg Simrit KG Weinheim, Germany Phone +49 (0) Simrit Phone +49 (0) Fax +49 (0) info@simrit.de 20 GB D&S. ABT

Merkel PRW 1 Double Wiper with Integrated Pressure Relieve. Product Information Merkel Hydraulics

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