P & P Technology Ltd

Transcription

1 P & P Technology Ltd General Information Produced effectively from a single continuous filament, knitted wire meshes produce very high levels of EMI shielding performance when evenly compressed between two metallic contact surfaces. KP meshes are offered in five basic wire types, each with its own specific characteristics, namely Monel, Aluminium, TCS (Tinned Copper-clad Steel), Brass and Stainless Steel. TCS is generally regarded as the most suitable for EMP shielding. Application - Where All knitted wire meshes will eventually take a compression-set as they are not as resilient as elastomer cored meshes (see section KE). For this reason they are generally used where the panel mating surfaces are permanent or fixed. Knitted meshes provide only limited environmental sealing and are normally used for applications that are not exposed to the elements unless protected by a further external elastomeric seal (see section KC). KP meshes have a long service life and a high temperature tolerance. Application - How Knitted mesh gaskets should be compressed by 20-25% of their relaxed height for optimum shielding effectiveness, unless surface irregularities prevent this, in which case an elastomer cored mesh (type KE), will generally be more suitable.

2 Gaskets may be retained in a groove or channel by friction-fit or they may be fixed by adhesive (the wire contact points can penetrate a thin film), welding and soldering. To facilitate clamping or riveting, `round-with-tail' or `double-round-with-tail' sections are available. Alternative fixing methods for knitted mesh gaskets utilize tandem or `Twinstrip' environmental seals (see KC series) and round-with-tail mesh factory fitted into aluminum mounting frames (series KM), which may be pre-drilled for ease of fitment. Specifications Monel BS3075 NA13 (0.11 mm diameter) Aluminum 5056 AMS 4182 (0.13 mm diameter) T.C.S ASTM B520 (0.11 mm diameter) Stainless Steel Alloy 304 (0.13 mm diameter)

3 Tolerances General - +/- 0.8 mm on all dimensions. How to Order Standard sizes may be specified from the table which follows.

4

5 General Information Elastomer-cored knitted wire meshes offer the shielding effectiveness of the all-mesh types by the utilising two layers of knitted wire over a low-closing-force rubber or elastomer core. In some cases a single mesh layer may suffice and in extreme cases such as EMP seven layers are generally employed (TCS mesh). Cored knitted mesh may be combined with an environmental seal in tandem to provide IP ratings of IP65 or higher, according to the materials used and the suitability of the mating surfaces (see the KC series). Core materials are usually sponges (EPDM or PU) although for many applications a silicone or neoprene tube is specified. Application - Where The elastomer core provides are high degree of recovery particularly in comparison with the `solid' mesh types and is therefore more suitable for doors and covers which are regularly opened and closed. The closing pressure is far lower and a good EMI shield can be formed even where minor surface irregularities exist. KE gasketing will provide limited environmental sealing particularly against dust. Flurosilicone or other special formulations are available to order, where hazardous conditions exist. Standard wire types are as the KP series.

6 Application - How Knitted mesh gaskets with elastomer core are fitted in a similar manner to the all-mesh KP type and may be retained in a groove or channel by friction-fit or they may be fixed by adhesive (the wire contact points can penetrate a thin film). To facilitate clamping or riveting, `round-with-tail' or double-round-with-tail' sections are available. Many KE series cross-sections are available with a PSA (pressure sensitive adhesive) backing, applied part-way across one face. Alternative fixing methods for cored mesh gaskets utilize tandem or `Twinstrip' environmental seals (see KC series) and round-with-tail mesh factory fitted into aluminum mounting frames (series KM), which may be pre-drilled for ease of fitment. Specifications Monel BS3075 NA13 (0.11 mm diameter) Aluminum 5056 AMS 4182 (0.13 mm diameter) T.C.S ASTM B520 (0.11 mm diameter) Stainless Steel Alloy 304 (0.13 mm diameter) Silicone Sponge AMS Silicone Solid ZZ-R Neoprene Sponge Mil-R Neoprene Solid Mil-R Performance Shielding effectiveness in db, typical values in accordance with MIL-STD-285 are shown in the KP series section. Tolerances General - +/- 0.8 mm on all dimensions.

7 How to Order Standard sizes may be specified from the table which follows. Alternatively, specify Group - Wire Code - Style - Size/Dimensions Group Elastomer Wire Code Style Size KE SS- Silicone Sponge M- Monel 60 Round xxxxxxxx - ST- Silicone Tube A- Aluminum 70 Rectangular (mm) - NS- Neopropene Sponge T - TCS 80 Round with tail - - NT- Neopropene Tube S Stainless Steel 90 Double round with tail - - Solid Silicone B - Brass NX Solid Neopropene Suffix #1 (n) number of layers. Suffix #2 S/A = Self adhesive - - Examples : KE MST (1) tube) ( 2.4 mm diameter round 1 x Monel layers over silicone KE ANS S/A (3.2 x 9.5 mm rectangular neoprene sponge with 2 x Aluminum mesh layers and PSA backing.

8

9 General Information Series KC or Twinstrip is a combination of a knitted mesh or cored mesh gasket in tandem with a non-conductive environmental seal. The wire mesh types are Monel, Aluminium, TCS and Stainless Steel and the permutations of wire and elastomer combinations are almost endless thus providing a large selection of environmental, water, dust and pressure seals. KC materials may be supplied as gaskets, in strip form or as pre-cut kits, ready bagged and labeled to suit specific enclosures. Limit stops and collars may be fitted to prevent over-compression or the distortion of mating surfaces. Application - Where For enclosure doors and covers it is used where an environmental or high IP rated seal is required alongside an EMI gasket, KC materials provide the shielding levels of knitted meshes plus the environmental protection of sponge, tubular or solid rubbers. Flurosilicone and other chemical resistant elastomers may be employed for use in hazardous applications such as the presence of hydrocarbon contamination.

10 Application - How Most Twinstrips have a PSA backing with peel-off covering enabling gaskets to be immediately bonded into position. The adhesive also helps unmounted gaskets to retain their shape during production and storage. Having a `carrier' to hold mesh gasketing in position enables the gasket to be mounted onto any flat surface without the need for a groove or channel to retain it. For many applications, particularly where the gasket is fitted inside a rack or enclosure, pre-cut and mitred adhesive-backed lengths of Twinstrip offer a fast and effective solution with considerable cost, packaging and space savings. Specifications Monel - BS3075 NA13 (0.11 mm diameter) Aluminum 5066 AMS 4182 (0.13 mm diameter) T. C. 5 ASTM B520 (0.11 mm diameter) Stainless Steel Alloy 304 ( 0.11 mm diameter) Silicone Sponge AMS 3195 Silicone Solid ZZ- R- 765 Neoprene Sponge Mil-R-6130 Neoprene Solid Mil-R-6855 Performance Shielding effectiveness in db, typical values in accordance with MIL-STD-285 are shown in the KP series section Tolerances Wire meshes, generally +/- 0.8 mm on diameter, width and height. Linear measurements on gaskets up to 300 mm +/- 0.8 mm, up to 1000 mm +/- 1.5 mm. Sponge Elastomers +/- 0.8 mm above 4.5 mm diameter, +/- 0.4 mm below this size. Solid Elastomers +/- 0.8 mm above 4.5 mm diameter, +/- 0.4 mm below this size.

11 How to Order Standard sizes may be specified from the table which follows. Alternatively specify; Group - Mesh portion - Elastomer - Size/Dimensions Group Mesh portion Elastomer Size of rubber KC As KP/KE series SS Silicone Sponge xxxx-xxxx - - NS Neopropene Sponge NX Neopropene Solid SX Silicone Solid - - ES EPDM Sponge - Suffix #1 ( after mesh portion) = Number of layer of mesh Suffix #2 (after final dimensions) = S/A if self-adhesive (default is, no S/A). Examples : KC MST (1) ( NS S/A) = Monel mesh ( 1 layer ) over 3.2 diameter Silicone tube bonded to Neoprene sponge of 3.2 x 12.7 mm rectangular section (self adhesive). For gaskets or strips material not showing, please send a drawing or specification and we will allocate a part number when we provide our quotation. Tolerances Wire meshes, generally +/- 0.8 mm on diameter, width and height. Linear measurements on gaskets up to 300 mm +/- 0.8 mm, up to 1000 mm +/- 1.5 mm. Sponge Elastomers +/- 0.8 mm above 4.5 mm diameter, +/- 0.4 mm below this size. Solid Elastomers +/- 0.8 mm above 4.5 mm diameter, +/- 0.4 mm below this size. How to Order Standard sizes may be specified from the table which follows. Alternatively specify; Group - Mesh portion - Elastomer - Size/Dimensions

12

13 Knitted Mesh with Carrier KM Series General Information Series KM gasket strip and frame materials comprise a slotted aluminium extrusion carrier into which a solid or elastomer cored knitted mesh gasket section is clamped. Ready-to-fit, these semi-rigid gasketing profiles help to avoid the problems often encountered when fitting adhesive-backed or plain mesh gaskets. KM series mesh sections with aluminium carrier may be supplied with dual gaskets, one on either side of the carrier, where one gasket is of mesh construction and the other is an environmental seal. The aluminium extrusion acts as a limit stop, thus controlling the even compression of the gaskets. Application-Where Covers, door frames and other apertures where the surrounding metalwork is either insufficiently rigid or of a heavy duty requiring a robust and well anchored gasket that is less affected by the stresses and shearing action imposed on conventional twinstrip gasketing. KM Series Application - How KM mesh with aluminium carrier is generally supplied as straight lengths (up to 4 metres), as welded/jointed frames to suit specific apertures, or as mitre-cut sections ready to mount around cabinets, doors or hatches. In most cases the aluminium carrier is drilled and countersunk to accept screws or rivets and may, under less stringent conditions, be fixed utilising a highbond PSA tape backing. This method is more suitable for frames rather than strips. Welding is possible but not recommended as damage to the mesh or elastomer gasketing is then very difficult to repair. Specifications Wire mesh and elastomer specifications are as shown in the KP, KE and KC sections. The extruded aluminium carrier is to BS with Alocrom 1200 surface treatment. Performance Shielding effectiveness in db, typical values in accordance with MIL-STD-285 are shown in the KP series section. Tolerances Wire meshes, generally +/- 0.8 mm on diameter, width and height. Linear measurements on gaskets up to 300 mm +/- 0.8 mm, up to 1000 mm +/- 1.5 mm. Sponge Elastomers +/- 0.8 mm above 4.5 mm diameter, +/- 0.4 mm below this size. Solid Elastomers +/- 0.8 mm above 4.5 mm diameter, +/- 0.4 mm below this size.

14 How to Order Standard sizes may be specified from the table which follows. Alternatively specify; Group - Carrier - Mesh portion - Elastomer portion (where applicable) - Elastomer Size Group Carrier Mesh portion Elastomer Size of rubber KM CS2 As KP/KE series SS Silicone Sponge xxxx-xxxx NS Neoprene Sponge NT Neoprene Tube* SX Silicone Tube* * with lag for twin slot carries - If second gasket/seal material on CS7, 8 and 9 is not specified it defaults to being the same as the first material. If a suffix in brackets is shown after the mesh part number this indicates the number of mesh layers. The default is two (2) layers and does not need to be specified. Example KM-CS8-M ST indicates a base material comprising carrier section CS8 with 6.4 mm diameter Monel mesh fixed to one side and a silicone rubber tube of 6.4 mm o.d. and 4.8 mm i.d. on the opposing side. Example KM-CS1-ASS indicates a base carrier section CS1 with an aluminium mesh covered silicone sponge gasket section on one side only. For gaskets or strip material not shown, or specific shapes, made-up frames and fixing hole positions, please send a drawing or specification and we will allocate a part number when we provide our quotation. SERIES KM CARRIER SIZES

15 Knitted Mesh - KW Series General Information Knitshield KW mesh bandage is a tubular form knitted stocking supplied in flat tape form. KW tapes are offered in the five basic wire types, namely Monel, Aluminum, TCS (Tinned Copper-clad Steel), Brass and Stainless Steel. Application - Where KW tapes are generally used to wrap cableforms, wiring systems or conduit to provide a high integrity 4-layer screen which can greatly reduce radiated interference if adequately grounded. Application - How The tape is a nominal 0.4 mm thick and should be spirally overlapped 50% to provide full screening effectiveness. Termination at each end should be by soldering or clamping, avoiding twisting into a pigtail which could effectively become an antenna. Specifications Wire specifications as standard are shown in section KP on page P1 together with shielding effectiveness data.

16 How to Order Specify Series KW, wire type and part number from the table which follows. Group Wire Code Style Size KW M Monel 55 ( flat tape) 0127 (12.7mm ) - A Aluminum (25.4mm ) - T TCS ( 50.8mm ) - S Stainless Steel B - Brass - - Knitted Mesh - KR Series General Information Knitshield KR compressed mesh washers, gaskets and seals utilize knitted mesh formed under pressure into resilient high density profiles. Application - Where

17 KR compressed mesh profiles are used as gland rings, grounding buttons, EMP gaskets, magnetron seals and numerous other applications where a higher mesh density is necessary. Application - How Each application is individual and related to the specific shielding and mechanical properties of the gasket. Please discuss your requirements with our engineers. Specifications Wire specifications as standard are shown in section KP together with shielding effectiveness data. How to Order Specify series KR, wire type and describe your component by its outside and inside diameters plus thickness (if an o -ring) or by means of a drawing if a formed gasket or profile section. Examples KR-B is a brass washer 25.4 x 15.9 x 3.2mm KR-M-99-Drg: AZ1234 is a gasket form in Monel to Drg: AZ1234 * For further details of how to specify please contact our Sales Office. P & P Technology Ltd Finch Drive Springwood, Braintree Essex CM7 2SF Telephone:+44 (0) Fax:+44 (0) info@p-p-t.co.uk Enquiries:technical@p-p-t.co.uk Link: