ERIKS - Technical Manual - O-Ring Gland Design Information

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SEALINGELEMENTS12. O-ring Gland DesignThe following pages contain basicO-ring gland design information.Please contact the local ERIKS representative if an application does notclearly fall into these design parameters.Static ApplicationsThere are five types of static O-ringapplications: Flange seal Radial seal Dovetail seal Boss seal Crush sealFlange Seal (Axial Seal)In flange seal glands, the two flangesare assembled with metal to metalcontact. So in fact there is noremarkable gap and no risk forextrusion of the O-ring as long as theconstruction does not deform undersystem pressure.(fig. 1-26).When system pressure is from the outside, the groove inside diameter is ofprimary importance and the groovewidth then determines the outsidediameter. When system pressure isfrom the inside the reverse is true.Radial SealBecause the metal parts are pressedor screwed together there is always aclearance gap with risk for extrusion.(fig. 1-27).Dovetail sealAlso here there is a metal to metal contact as long as the construction will notdeform under system pressure.(fig. 1-30).Boss sealThe groove dimensions are incorporatedin the standard dimensions.102PressureoutsidePressureinsideFig. 1-26x surface finish in µ RaFig. 1-30Surface Finish Static GroovesStraight-sided grooves are best to prevent extrusion or nibbling. Five degreesloping sides are easier to machineand are suitable for lower pressures.Surface finishes up to 64 to 125 RMSwith no burrs, nicks, or scratches arerecommended.The method used to produce the finishis important. If the finish is producedby machining the part on a lathe, or bysome other method that producesscratches and ridges that follow thedirection of the machinehead, a veryrough surface will still seal effectively.Other methods, however, such as endmilling, will produce scratches that cutacross the O-ring. Even these mayhave a rather high roughness value ifthe profile across them shows roundedscratches that the rubber can readilyflow into.Fig. 1-27

TECHNICALDOCUMENTATIONO-RINGS12. O-ring Gland DesignDynamic ApplicationsThere are three types of dynamic applications: Reciprocating Seal Oscillating Seal Rotating SealApplication in reciprocating andoscillating motionsGroove dimensions for reciprocatingand oscillating applications are thesame.Dynamic applications, due to themotion against the O-ring, are morecomplicated than static applications.Fluid compatibility must be more carefully scrutinized because a volumeswell of more than 20% may lead todifficulties with high friction problemsand only a minimum of shrinkage, atmost 4%, can be tolerated to avoidleakage problems.Because of the movement between thegland parts there always is a clearancegap with a potential risk for extrusion ofthe O-ring.O-ring seals are best in dynamic applications when used on short stroke,relatively small diameter applications.Long stroke, large diameter seals aremore susceptible to spiral failure.Fig. 1-33Application of O-rings in rotarymotionsIn a rotating application a shaft continuously rotates in the inside diameter ofthe O-ring, causing friction and heat.Because rubber is a poor conductor ofheat, the O-ring can loose its properties. To minimize or reduce wear, thefollowing could be done; howeverconsult the local ERIKS representative: confirm amount of squeeze. use the smallest possible crosssection. select an O-ring with internal lubrication or use low friction minerals. do not exceed a temperature of212 F (100 C). do not use a shaft which is largerthan the inside diameter of the Oring. provide lubrication. do not let the O-ring rotate in thegroove, only relative to the shaft. rough sealing surfaces of the groovewill prevent rotation. check surface finish(may be too rough)Installing the O-ringMating metal surfaces are generally ofdifferent metals, with one metal beingsofter than the other. The O-ringgroove should be put in the softer ofthe metals. In the event that the metalswear on each other the harder metalwill be less damaged, thus insuring agood sealing surface.Surface Finish for Dynamic GroovesStraight-sided grooves are best to prevent extrusion or nibbling. Five degreesloping sides are easier to machineand are suitable for pressures up to1500 psi. (100 bar). The rubbing surfaces should be 8 to 16 RMS withoutlongitudinal or circumferential scratches.Best surfaces are honed, burnished, orhard chrome plated. Finishes ofdynamic contacting surfaces have a lotto do with the life of the O-ring seals.Appropriate surface finishes are important. Limits of maximum roughness forglands are given. Rougher finishes willcause excessive wear. Finer finishesreduce lubrication to the O-ring andmay result in stick slipping and irregular wear. Surface roughness valuesless than 5 micro inches (0,15µmRa)are not recommended for dynamic Oring seals. The surface must be roughenough to hold small amounts of oil.Finishes below 5 RMS wipe too cleanfor good moving seal life.Steel or cast iron cylinder bores arepreferred. They should be thickenough not to expand or breathe withpressure, otherwise the radial clearance gap may expand and contractwith pressure fluctuations-causingnibbling of the O-ring.103

SEALINGELEMENTS12. O-ring Gland DesignFrictionIn normal applications harder materialsprovide less friction than softer materials. However, the higher the hardnessof the O-ring, above 70 Shore A, thegreater the friction. This is because thecompressive force at the samesqueeze, is greater than with softermaterials.Compound swell decreases the hardness and may increase friction. Thelower the operating temperature theharder the seal becomes which canalso increase friction. However, thermal contraction of the seal materialwhich reduces effective squeeze mayoffset any increased friction caused byan increase of hardness.Breakout friction is the force necessaryto start relative motion. This is dependent upon the length of the timebetween cycles. It also depends on thesurface finish of the metal, the rubberhardness, squeeze, and other frictionaffecting factors. After standing 10days, the breakout friction will be 2 to5 times the friction of a seal under lightload. Breakout friction can be reducedby utlizing softer O-ring or speciallymodified compounds.Running friction depends on two factors: the force exerted on the ring'srubbing surface by the compressionforce of the squeeze and the force ofthe system's pressure against andtending to distort the O-ring into a "D"shape. The former depends on thehardness of the O-ring, its percentagesqueeze and the length of the rubbingsurface.The surface over which the O-ring willslide also becomes very important. Itmust be hard and wear resistant, itmust be sufficiently smooth that it willnot abrade the rubber, and yet theremust be minute pockets to hold lubricant.104Soft metals like aluminum, brass,bronze, monel, and some stainlesssteels should be avoided.Metallic moving surfaces sealed by anO-ring preferably should never touch,but if they must, then the one containingthe O-ring groove should be a softbearing material.If excessive clearance is created,extrusion will result. If adequatesqueeze has not been applied, leakagewill result.If friction is excessive a variety ofpossible solutions exist: Select a different O-ring hardness. Select a different O-ring material withimproved coefficient of friction. Increase the groove depth. Consider the use of an alternatedesign of seal. Viton has much lower friction thanNBR or EPDM or Silicone. Check to ensure squeeze is withinthe recommended range. Do not reduce the squeeze belowrecommended levels in an attempt toreduce friction. The reduction insqueeze will cause the application toleak.Seal extrusionIf the radial clearance gap betweenthe sealing surface and the groovecorners (clearance gap) is too largeand the pressure exceeds the deformation limit of the O-ring, extrusion ofthe O-ring material will occur.When this happens, the extrudedmaterial wears or frays with cyclingand the seal starts to leak.For extrusion and direction of pressureinformation for static seals seefig. 1-26. In a reciprocating applicationthe tendency for extrusion willincrease if friction and system pressure act on the O-ring in the samedirection. Groove design can reducethe tendency for extrusion.See figures 1-32 a & b.If the friction of the moving metal surface across the O-ring is in the samedirection as the direction of the pressure, the O-ring will be dragged intothe clearance gap more readily andthus extrude at about 35% of thepressure normally necessary to causeextrusion. By placing the groove in theopposite metal part, the friction willwork against pressure.One of the best ways to reduce extrusion is to use the back-up ring (seepage 117).P MediaP ig. 1-32 aClearancegapFig. 1-32 b

TECHNICALDOCUMENTATIONO-RINGS12. O-ring Gland DesignGroove depth and clearance gapThe right groove depth in O-ring applications is very important because itstrongly influences the squeeze of theO-ring cross section. In the tables thegroove depth always includes themachined groove depth and theclearance gap. The clearance gapinfluences the rate of extrusion.Because it is very difficult to measurethe groove depth it is better to makethe calculation with the bore, plug andgroove diameter as stated below.clearance gappressureMechanical Squeeze for the gland isdetermined by the bore diameter andthe groove diameter in a plug or maletype seal (fig. 23). The formula fordetermining the groove diameter(B)when the bore diameter(A) and glanddepth(E) are known is:Seal DesignSeals are divided into three primarycategories: Static Face or Flange,Static Radial type, and Dynamic Radialtype.Face or Flange type seals have noclearance gap, but consist of a groovecut into one flange with a flat matingflange bolted together to give a surfaceto surface contact.Static Radial Seals and Dynamic RadialSeals require the presence of a diametrical clearance gap for installation.B min. A min. minus 2 x E max.B max. A max. minus 2 x E min.Squeeze is measured from the bottomof the groove to the mating surfaceand includes the clearance gap. Thefollowing formula is used to determinethe actual gland depth with tolerances:There are two types of radial designs:1. Male or Plug - the O-ring groove islocated on a plug which is inserted intothe housing or cylinder (fig. 1-23)2. Female or Tube - the O-ring grooveis located in the housing or cylinderand a tube is installed through theO-ring l.D. (fig. 1-24).Max. Gland Depth max. bore minusmin. groove diameter, divided by 2.Min. Gland Depth min. bore minusmax. groove diameter, divided by 2.Fig. 1-19Male or Plug Seal design is based onthe following factors (refer to fig. 1-23).Bore Diameter (A)Plug Diameter (H)Groove Diameter (B)Groove Width (F) as shown in thedimension tables.Gland Depth (E) as shown in thedimension tables.Break corners app. R .005 (0,15)AHFig. 1-23BEx surface finish µ Ragroove depth is incl. gapAHDFig. 1-24F105

SEALING12. O-ring Gland DesignTotal Diametrical Clearance is the difference between the bore diameter (A)and the plug diameter (H) dimensions.Tolerances of the bore and plugdiameters determine the maximum andminimum diametrical clearance gap.These values divided by two will givethe radial maximum and minimumclearance gaps.Female or Tube seals (fig 24) arebased upon the following:Bore Diameter (A)Plug Diameter (H)Groove Diameter (D)Groove Width (F) as shown in thedimension tables.Gland Depth (E) as shown in thedimension tables.Mechanical Squeeze for this type ofseal is determined by the groovediameter (D) and the plug diameter (H).The formula for determining the groovediameter (D) when the plug diameter(H) and the groove depth (E) areknown is:D max. H max. Plus 2 E max.D min. H min. plus 2 E min.Squeeze is measured from the bottomof the groove to the mating surfaceand includes the clearance gap. Usethe following formula for determiningthe actual gland depth with tolerance:Total Diametrical Clearance is the difference between the bore diameter (A)and the plug diameter (H). Tolerancesof the bore diameter and the plugdiameter determine the maximum andminimum total diametrical clearancegap. The size of the clearance gap isalso influenced by the degree of"breathing" of the metal parts. Whenusing the values from the tables,include in the diametrical clearanceany breathing or expansion of themating metal parts that may beanticipated due to pressure.In some constructions the clearancegap is equal on the whole circumference of the O-ring. This is total clearance with maximum concentricity. Ifconcentricity between piston andcylinder is rigidly maintained, radialclearance is diametrical clearance.In practice in most constructions, dueto side loading and misalignment, onone spot of the O-ring circumferencethe clearance gap is minimum or evenzero and on the opposite spot it will bemaximum. This is total clearance withmaximum eccentricity. (fig.20) Please contact the local ERIKSrepresentative for additional information on wear bands and bearing forimproving concentricity.SboreMax. Gland Depth Max. groove diameter minus min. plugdiameter, divided by 2.Min. Gland Depth Min. groove diameter minus max. plugdiameter, divided by 2.rodtotal clearancewith max. eccentricitytotal clearancewith max. concentricityFig. 1-20106SELEMENTS

TECHNICALDOCUMENTATIONO-RINGS12. O-ring Gland DesignThe most effective and reliable sealingis generally provided with the diametrical clearance as shown in Table 3.B1a. The maximum allowable gaps areindicated for 70 hardness O-ringswith different cross sections withoutback-ups for reciprocating and staticseals. These values correspond to apressure of ca. 1200 PSI (80 bar)(8 Mpa) at 70 F (21 C). When greaterclearances occur, fig. 1-21 indicatesconditions where O-ring seals may beused - depending on the fluid pressureand O-ring hardness.[See Table 3.B-1a]Table 3.B-1a Gland clearance in relation to hardness and O-ring cross sectioninch.070.103.139.210 .275Cross sectionmm1,0-2,02,0-3,03,0-4,04,0-6,0 6,0Max. clearance 70 Shore Ainchmm.002 - .0040,05 - 0,1.002 - .0050,05 - 0,13.002 - .0060,05 - 0,15.003 - .0070,07 - 0,18.004 - .0100,1 - 0,2510.500 (700)9.000 (600)Note: for silicone and fluorosiliconeO-rings reduce all the clearancesshown by 50%.Pressure psi (bar)The diagram (fig. 1-21) gives a guideto the relation between hardness,pressure, clearance, and extrusion.This figure is based on NBR O-ringswith a cross section of .139 inch (3,53mm) without back up rings. Whenthere is risk for extrusion use contoured hard rubber or plastic back-uprings. The results are based on tests attemperatures up to 70 C.4.500 (300)3.000 (200)2.000 (140)1.500 (100)extrusion1.000 (70)825 (55)600 (40)90 Sh.A450 (30)300 (20)225 (15)70 Sh.Anoextrusion150 (10)inchmm.0100,25.0200,5.0300,7.0401,0Total Diametral Clearance GapFig. 1-21107

SEALINGELEMENTS12. O-ring Gland Design12 A. Gland Design Static AxialApplicationGland Design for Static Application forO-rings with Axial SqueezePressureoutsidePressureinsideFig. 1-26Surface Finish Xgroove top and bottom :for liquidsX 32 micro inches (0.8 µm Ra)Break corners app. R .005 (0,15)for vacuum and gasesX 16 micro inches (0.4 µm Ra)groove sides:X 63 micro inches (1.6 µm Ra)x surface finish µ Ragroove depth is incl. gapFig. 1-27 aTable AS C1 - Gland Dimensions (inches) Industrial Face or Flange TypeO-ringCross 101/4.275Gland DepthAxial Static tatic Squeezefor Face SealsActual ove 7.270/.290.342/.362These dimensions are intended primarily for face type seals and normal temperature applications.108Vacuum & Groove 35

TECHNICALDOCUMENTATIONO-RINGS12. O-ring Gland DesignGland Design for Static Applicationfor O-rings with Axial SqueezeFace Seal Glands (METRIC)O-rings which are compressed axiallyin a static application are also calledflange seals. (see fig. 26 and 27).Surface Finish Xgroove top and bottom :for liquidsX 32 micro inches (0.8 µm Ra)for vacuum and gasesX 16 micro inches (0.4 µm Ra)groove sides:X 63 micro inches (1.6 µm Ra)* dimensions in mm *US/BS standardAS.568APressureoutsidePressureinsideFig. 1-26Break corners app. R .005 (0,15)x surface finish µ Ragroove depth is incl. gapFig. 1-27 aTable 3.C-1 Gland Dimensions Static Application-Face Seal Glands-MetricWO-ring cross sectionDiam.Tol. /mmDIN.37710,900,081,0 - 1,020,081,200,081,25 - 1,270,081,420,081,500,081,60 - 1,630,081,78* - 1,800,081,900,082,00,08EGland DepthFRGroove WidthGroove RadiusLiquidsVacuum/Tol. -0/ 41,431,51Tol. -0/ 0,020,020,020,020,020,020,030,030,030,042,20 - 0 - 054,104,600,50,50,50,50,54,504,704,805,05,33* - 0,8023,101,01,01,01,51,51,51,51,51,5109

SEALINGELEMENTS12. O-ring Gland Design12 B. Gland Design Static RadialApplicationGland Design for Static Applicationfor O-rings with Radial SqueezeIndustrial Radial Glands INCHESFig. 1-28Surface Finish Xgroove top and bottom :for liquidsX 32 micro inches (0.8 µm Ra)Break corners app. R .005 (0,15)for vacuum and gasesX 16 micro inches (0.4 µm Ra)groove sides:X 63 micro inches (1.6 µm Ra)x surface finish µ Ragroove depth is incl. gapFig. 1-27 aTable AS.C2 Gland Dimensions Static Seals - Industrial Radial Applications (Inches)O-ringCross sectionWNominal Actual1/163/321/83/161/4.070.103.139.210.275Gland Depth.Radial 29StaticSqueeze forRadial Standard*.002 min.*.002 min.*.003 min.*.003 min.*.004 035.020/.0351. Total Indicator Reading between groove and adjacent bearing surface.2. These groove dimensions are for compounds that free swell less than 15%. Suitable allowances should be made for higher swell compounds.* For max. allowable cleareance, refer to fig. 22 to determine value based upon pressure requirement and compound hardness.* Maximum clearance should be reduced by 1/2 for compounds exhibiting poor strength such as silicone and fluorosilicone.Male plug dimensions and female throat (bore) dimensions must be calculated based upon maximum and minimum clearance gaps.110

TECHNICALDOCUMENTATIONO-RINGS12. O-ring Gland Design12 B. Gland Design Static RadialApplicationGland Design for Static Applicationfor O-rings with Radial SqueezeIndustrial Radial Glands INCHESSurface Finish Xgroove top and bottom :for liquidsX 32 micro inches (0.8 µm Ra)for vacuum and gasesX 16 micro inches (0.4 µm Ra)groove sides:X 63 micro inches (1.6 µm Ra)Fig. 1-28Break corners app. R .005 (0,15)x surface finish µ Ragroove depth is incl. gapFig. 1-27 aTable 3.C-2 Gland dimensions Static Application-Industrial Radial Seals, METRICWO-ring cross sectionDiam.Tol. /mmDIN.3771EGland DepthS Diametr. F GrooveClearanceWidthTol.Tol. -0/ R GrooveMax.Radius EccentricityTol. -0/ 0,130,901,0 - 1,021,201,25 - 1,271,421,501,60 - 1,631,78* - 50,050,050,050,050,052,20 - ,050,050,053,03,153,50 - ,704,805,05,33* - ,130,130,130,130,130,130,130,13111

SEALINGELEMENTS12. O-ring Gland Design12 C. Gland Design Dovetail GroovesGland Design for a StaticApplication; for O-rings in DovetailGrooves, INCHESDovetail grooves are used to hold theO-ring in place during installation ormaintenance. This groove design isrelatively uncommon as it is expensiveto machine and should not be usedunless absolutely required.The dovetail groove construction isonly recommended for O-rings withcross sections of .139 inch(3,53 mm) and larger.Surface Finish Xgroove top and bottom :for liquidsX 32 micro inches (0.8 µm Ra)for vacuum and gasesX 16 micro inches (0.4 µm Ra)groove sides:X 63 micro inches (1.6 µm Ra)112x surface finish in µ RaFig. 1-30Table AS.C3 Gland Dimensions Dovetail Grooves, INCHESO-ringCross 375Gland Depth. 318.231/.23416.315/.31916Groove Widthto Sharp 235.315/.319Groove .090Radius "R2" is critical. Insufficient radius will cause damage to the seal during installation,while excessive radius may contribute to extrusion. R2 is size radius, R1 is machining radius.

TECHNICALDOCUMENTATIONO-RINGS12. O-ring Gland Design12 C. Gland Design Dovetail GroovesGland Design for a StaticApplication for O-rings in DovetailGrooves, METRICDovetail grooves are used to hold theO-ring in place during installation ormaintenance. This groove design isrelatively uncommon as it is expensiveto machine and should not be usedunless absolutely required.The dovetail groove construction isonly recommended for O-rings withbigger cross sections, .139 inch(3,53 mm) and bigger.Table 3.C-3 Gland Dimensions Dovetail Grooves, METRICWCross sectionmm3,03,5 - 3,53*EGroove DepthE 0/-0,052,402,80FGroove WidthF2 /-0,05F1 50,80,80,80,80,250,250,40,46,06,56,99* - 40,40,47,56,405,606,001,50,4for vacuum and gasesX 16 micro inches (0.4 µm 51,51,50,50,50,5groove sides:X 63 micro inches (1.6 µm ,707,407,951,50,5Surface Finish Xgroove top and bottom :for liquidsX 32 micro inches (0.8 µm Ra)Dimensions in mm *US/BS standard AS 568ARadius "R2" is critical. Insufficient radius will cause damage to the seal during installation,while excessive radius may contribute to extrusion.R2 is size radius. R1 is machining radius.F1 is groove width to sharp corner. F2 is groove width to round cornerx surface finish in µ RaFig. 1-30113

SEALINGELEMENTS12. O-ring Gland Design12 D. Gland Design for Static Boss SealsQCHAMFER RELIEF TOO-ring boss Gaskets for StraightThread Tube FittingsHEX FLATS SHOULDDIAMETERTO THIS POINTCENTRIC WITH THREAD P.D.WITHIN45 5 15 5 ANGLE AND EBE WITHIN THEJTHREAD.005 F.I.R.MIN. BOSS.010.005HEIGHTDIA LIMITATIONSThe 900-series of dash numbers identify the size of boss seals. The digitsafter the 9 identify the nominal tubesize in 16ths of an inch. The tube sizeis the outside diameter (OD). For example, size 903 is intended for use with3/16-inch OD tube.D SHOULD BE CON-FULL THREADSU DIA.F45 5 RAD100DETAILEO Y ‘A’DETAILSQUARENESS BETWEENTHREAD AND FACE OF HEXSHOULD NOT EXCEEDHWHEN MEASURED AT DIAMETER.015 RAD FORMIN.KTHREAD RUNOUTSPOT-THD.THIS DIM. APPLIESFACEPONLY WHEN TAP.031.016D DIA.DIAMETERRAD‘A’ZDRILL CAN NOT PASSETHRU ENTIRE BOSSBoss DimensionsAS 568O-ringSize Nr.CrosssectionI.D.TubeOutsideØThreadDmin.U .005-.000K .015-.000Ymin.Pmin.Z 1 0min.5/16-24 UNF-2B3/8-24 UNF-2B7/16-20 UNF-2B1/2-20 UNF-2B9/16-20 UNF-2B3/4-16 UNF-2B7/8-14 UNF-2B1 1/16-12 24-932.064 .003.064 .003.072 .003.072 .003.078 .003.087 .003.097 .003.116 .004.116 .004.116 .004.116 .004.118 .004.118 .004.118 .004.239 .005.301 .005.351 .005.414 .005.468 .005.644 .009.755 .009.924 .009.986 .0101.047 .0101.171 .0101.475 .0141.720 .0142.337 .0181/83/161/45/163/81/25/83/413/167/811 1/41 47.609.688.781.90612 12 12 12 12 15 15 15 .438.500.563.625.688.8751.0001.2501 3/16-12 UN-2B1 5/16-12 UN-2B1 5/8-12 UN-2B1 7/8-12 UN-2B2 1/2-12 9102.2702.5603.480.906.906.906.906.90615 15 15 15 15 1.3751.5001.8752.1252.750Fitting End Dimensions (MS33656)O-ringSize 4 .003.064 .003.072 .003.072 .003.078 .003.087 .003.097 .003.116 .004.116 .004.116 .004.118 .004.118 .004.118 .004.239 .005.301 .005.351 .005.414 .005.468 .005.644 .009.755 .009.924 .0091.047 .0101.171 .0101.475 .0141.720 .0142.337 1 1/41 1/22Thread5/16-24 UNF-2B3/8-24 UNF-2B7/16-20 UNF-2B1/2-20 UNF-2B9/16-18 UNF-2B3/4-16 UNF-2B7/8-14 UNF-2B1 1/16-12 UN-2B1 3/16-12 UN-2B1 5/16-12 UN-2B1 5/8-12 UN-2B1 7/8-12 UN-2B2 1/2-12 UN-2BF .002- 71.7562.381Dmax.U 1.8492.0952.718K .015- 25.125

TECHNICALDOCUMENTATIONO-RINGS12. O-ring Gland Design12 E. Gland Design Dynamic HydraulicBreak corners app. R .005 (0,15)Gland Design for DynamicApplication HydraulicINCHESThe following table indicates groovedimensions for reciprocating and oscillating applications when sealinghydraulic fluids and other viscousliquids.x surface finish µ Ragroove depth is incl. gapSurface Finish Xgroove top and bottom :X 16 micro inches (0.4 µm Ra)Fig. 1-33/34Fig. 1-27groove sides:X 32 micro inches (0.8 µm Ra)Table AS.D1 Gland Dimensions Dynamic Seals - Industrial Reciprocating Applications, InchesO-ringCross sectionWNominal Actual1/163/321/83/161/4.070.103.139.210.275Gland Depth.Radial 240DynamicSqueeze forRadial andard*.002 min.*.002 min.*.003 min.*.003 min.*.004 ooveWidth 0/.035.002.002.003.004.0051. Total Indicator Reading between groove and adjacent bearing surface.2. These groove widths are for compounds that free swell less than 15%. Suitable allowances should be made for higher swell compounds.** Groove width is based on rubber backups. For groove width with pdfe spiral wound backups see table 3.D-2.* For max. allowable cleareance, refer to table 13.A to determine value based upon pressure requirement and compound durometer.* The piston dimension for male glands must be calculated by using the max. gap derived from the extrusion table 13.A and the min. gap listed above.* The bore diameter for female glands must be calculated by using the max. gap derived from the extrusion table 13.A and the min. gap listed above.115

SEALINGELEMENTS12. O-ring Gland Design12 E. Gland Design Dynamic HydraulicTable 3.D-1 Gland Dimensions Dynamic Application-Industrial Reciprocating Seals, METRICGland Design for DynamicApplication HydraulicMETRICThe following table indicates groovedime

12. O-ring Gland Design Friction In normal applications harder materials provide less friction than softer materi-als. However, the higher the hardness of the O-ring, above 70 Shore A, the greater the friction. This is because the compressive force at the same squeeze, is greater than with softer materials. Compound swell decreases the hard-File Size: 338KBPage Count: 31Explore furtherO-Ring Groove Design Guide & Recommendations allorings.comwww.allorings.comO-Ring Groove Design Guides Engineering Quick Referencewww.marcorubber.comMetric O-Ring Groove Design Reference Guidewww.allorings.comDynamic O-Ring Design Chart Marco Rubber & Plastics .www.marcorubber.comO-ring Design, O-ring Design Guide, O-ring Seal Design .mykin.comRecommended to you b