parker hannifin seals o rings kits rotary seal hydraulic pneumatic seal manufacturers and dealers in india veer enterprise vardhman bearings
parker hannifin seals o rings kits rotary seal hydraulic pneumatic seal manufacturers and dealers in india veer enterprise vardhman bearings
O-Ring Kits Part Number Description Plastic Std. Kit E0515 Compound E0515-80 EPR 80 durometer O-rings per NAS 1613 rev. 2 in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit N0552 Compound N0552-90 NBR 90 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit N0674 Compound N0674-70 NBR 70 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit V0747 Compound V0747-75 FKM 75 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit V0884 Compound V0884-75 FKM (brown) 75 durometer O-rings in 37 popular AS568 sizes / 513 O-rings N1470 AS568 Kit #1 Compound N1470-70 NBR 70 durometer in 30 popular sizes / 382 O-rings N1470 Metric Kit #1 Compound N1470-70 NBR 70 durometer in 32 popular metric sizes / 372 O-rings N1490 Boss Kit Compound N1490-90 NBR 90 durometer in 20 standard tube fitting sizes Note: Boxes and plugs are available as separate items
3.1.6 Accessories 3.1.6.1 Extraction Tools These unique double-ended tools make life easier for those who have to frequently install or remove O-rings from hydraulic or pneumatic cylinders and equipment. They are available in brass or plastic with or without a convenient carrying case. 3.1.6.2 O-Ring Sizing Cone A unique measuring cone and circumference “Pi” tape provide quick and easy o-ring sizing information to determine the nearest standard Parker o-ring size. Please note: the cone and tape do not measure actual dimensions of a part and cannot be used for pass/fail inspections. See table 3-3 for part number information. 3.1.6.3 O-Ring Kits When part numbers are missing, seal dimensions are unknown, and the parts themselves are unavailable from the equipment OEM, these o-ring kits can save the day, not to mention hours of downtime. More than eight different standard kits give you a choice of compounds and o-ring sizes for a wide range of sealing applications. The end result? Multiple sealing solutions for the same cost as a single OEM replacement part. We’ll even build custom kits using any of our 200-plus compounds. Please see table 3-4 through table 3-7 for detailed kit information. O-Ring Extraction Tools and Cone Part Numbers Part Number Description Brass Extraction Kit Brass extraction pick and spat in plastic pouch Plastic O-ring Pick Plastic extraction pick Plastic Sizing Cone O-ring sizing kit Notes: Private labeling is available. Table 3-3: Extraction Tools and Cone Part Numbers O-Ring Kits Part Number Description Plastic Std. Kit E0515 Compound E0515-80 EPR 80 durometer O-rings per NAS 1613 rev. 2 in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit N0552 Compound N0552-90 NBR 90 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit N0674 Compound N0674-70 NBR 70 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit V0747 Compound V0747-75 FKM 75 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit V0884 Compound V0884-75 FKM (brown) 75 durometer O-rings in 37 popular AS568 sizes / 513 O-rings N1470 AS568 Kit #1 Compound N1470-70 NBR 70 durometer in 30 popular sizes / 382 O-rings N1470 Metric Kit #1 Compound N1470-70 NBR 70 durometer in 32 popular metric sizes / 372 O-rings N1490 Boss Kit Compound N1490-90 NBR 90 durometer in 20 standard tube fitting sizes Note: Boxes and plugs are available as separate items. Table 3-4: O-Ring Kits AS568 Kit #1 Sizes Size Dimensions Quantity 2-006 0.114 x .070 20 2-007 0.145 x .070 20 2-008 0.176 x .070 20 2-009 0.208 x .070 20 2-010 0.239 x .070 20 2-011 0.239 x .070 20 2-012 0.364 x .070 20 2-110 0.362 x .103 13 2-111 0.424 x .103 13 2-112 0.487 x .103 13 2-113 0.549 x .103 13 2-114 0.612 x .103 13 2-115 0.674 x .103 13 2-116 0.737 x .103 13 2-210 0.734 x .139 10 2-211 0.796 x .139 10 2-212 0.859 x .139 10 2-213 0.921 x .139 10 2-214 0.984 x .139 10 2-215 1.046 x .139 10 2-216 1.109 x .139 10 2-217 1.171 x .139 10 2-218 1.234 x .139 10 2-219 1.296 x .139 10 2-220 1.359 x .139 10 2-221 1.421 x .139 10 2-222 1.484 x .139 10 2-225 1.475 x .210 7 2-226 1.600 x .210 7 2-227 1.725 x .210 7 Table 3-5: AS568 Kit #1 Sizes Parker Metric Kit #1 Sizes Dimensions Quantity Dimensions Quantity 3.00 x 2.00 20 22.00 x 2.50 14 5.00 x 2.00 20 22.00 x 3.50 10 6.00 x 2.00 18 23.00 x 3.50 10 8.00 x 2.00 18 25.00 x 3.50 10 10.00 x 2.00 18 27.00 x 3.50 10 10.00 x 2.50 14 28.00 x 3.50 10 12.00 x 2.50 14 30.00 x 3.50 10 13.00 x 2.00 18 31.00 x 3.50 10 14.00 x 2.50 14 32.00 x 3.50 10 15.00 x 2.50 14 34.00 x 3.50 10 16.00 x 2.50 14 36.00 x 3.50 10 18.00 x 2.50 14 38.00 x 3.50 10 18.00 x 3.50 10 41.00 x 3.50 10 20.00 x 2.50 14 44.00 x 3.50 10 20.00 x 3.50 10 46.00 x 3.50 10 21.00 x 2.50 14 50.00 x 3.50 10 Table 3-6: Parker Metric Kit #1 Sizes 3-7O-Ring Applications Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com Parker O-Ring Handbook Effects of Cross Section Larger Section Smaller Section Dynamic Reciprocating Seals More stable Less stable More friction Less friction All Seals Requires larger supporting structure Requires less space — reduces weight Better compression set(1) Poorer compression set(1) Less volume swell in fluid More volume swell in fluid Less resistant to explosive decompression More resistant to explosive decompression Allows use of larger tolerances while still controlling squeeze adequately Requires closer tolerances to control squeeze. More likely to leak due to dirt, lint, scratches, etc. Less sensitive to dirt, lint, scratches, etc. Better physical properties(2) Poorer physical properties(2) Cost and availability are other factors to consider, and these would need to be determined for the particular sizes being considered. (1) Particularly true for nitrile and fluorocarbon elastomers. Doubtful for ethylene propylenes and silicones. (2) Applies to tensile and elongation of nitriles, elongation of fluorocarbons. Table 3-8: Effects of Cross Section 3.2 Cleanliness Cleanliness is vitally important to assure proper sealing action and long O-ring life. Every precaution must be taken to insure that all component parts are clean at time of assembly. Foreign particles — dust, dirt, metal chips, grit, etc.— in the gland may cause leakage and can damage the O-ring, reducing its life. It is equally important to maintain clean hydraulic fluids during the normal operation of dynamic seal systems. Costly shut downs necessitated by excessive seal wear and requiring early seal replacement may be prevented by the use of effective filters in the fluid power system as well as installing wiper rings on actuating rods exposed to external dust, dirt and other contaminants. 3.3 Assembly Assembly must be done with great care so that the O-ring is properly placed in the groove and is not damaged as the gland assembly is closed. Some of the more important design features to insure this are: 1. The I.D. stretch, as installed in the groove, should not be more than 5%. Excessive stretch will shorten the life of most O-ring materials. Also, see Figure 3-3 for data on the flattening effect produced by installation stretch. 2. The I.D. expansion needed to reach the groove during assembly ordinarily does not exceed 25-50% and should not exceed 50% of the ultimate elongation of the chosen compound. However, for small diameter O-rings, it may be necessary to exceed this rule of thumb. If so, sufficient time should be allowed for the O-ring to return to its normal diameter before closing the gland assembly. 3. The O-ring should not be twisted. Twisting during installation will most readily occur with O-rings having a large ratio of I.D. to cross-section diameter. Parker Boss Kit Sizes Size Dimensions Tube OD Quantity 3-901 0.185 x .056 3 ⁄32 10 3-902 0.239 x .064 1 ⁄8 10 3-903 0.301 x .064 3 ⁄16 10 3-904 0.351 x .072 ¼ 10 3-905 0.414 x .072 5 ⁄16 12 3-906 0.468 x .078 3 ⁄8 12 3-907 0.530 x .082 7 ⁄16 12 3-908 0.644 x .087 ½ 12 3-909 0.706 x .097 9 ⁄16 12 3-910 0.755 x .097 5 ⁄8 12 3-911 0.863 x .116 11⁄16 10 3-912 0.924 x .116 ¾ 10 3-913 0.986 x .116 13⁄16 10 3-914 1.047 x .116 7 ⁄8 10 3-916 1.171 x .116 1 10 3-918 1.355 x .116 11 ⁄8 10 3-920 1.475 x .118 1¼ 10 3-924 1.720 x .118 1½ 10 3-928 2.090 x .118 1¾ 10 3-932 2.337 x .118 2 10 Table 3-7: Parker Boss Kit Sizes 4. O-rings should never be forced over unprotected sharp corners, threads, keyways, slots, splines, ports, or other sharp edges. If impossible to avoid by proper design, then thimbles, supports, or other shielding arrangements must be used during assembly to prevent damage to the seal. See Figure 3-4. 5. Closure of the gland assembly must not pinch the O-ring at the groove corners. 6. Gland closure should be accomplished by straight longitudinal movement. Rotary or oscillatory motion is undesirable since it may cause bunching, misalignment and pinching or cutting of the seal. 3.4 Selecting the Best Cross-Section In designing an O-ring seal, there are usually several standard cross-section diameters available. There are a number of factors to consider in deciding which one to use, and some of these factors are somewhat contradictory. In a dynamic, reciprocating application, the choice is automatically narrowed because the design charts and tables do not include all the standard O-ring sizes. For any given piston or rod diameter, O-rings with smaller cross-section diameters are inherently less stable than larger cross-sections, tending to twist in the groove when reciprocating motion occurs. This leads to early O-ring spiral failure and leakage. The smaller cross-sections for each O-ring I.D. dimension are therefore omitted in the reciprocating seal design tables. Nevertheless, for many dynamic applications, there is still some choice as to cross-section, and the larger cross-sections will prove to be the more stable. Counterweighing this factor, is the reduced breakaway and running friction obtainable with a smaller cross-section O-ring. These and other factors to be considered are tabulated on Table 3-8. 3-8 Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com O-Ring Applications Parker O-Ring Handbook 3.5 Stretch When an O-ring is stretched, its cross-section is reduced and flattened. When the centerline diameter is stretched more than two or three percent, the gland depth must be reduced to retain the necessary squeeze on the reduced and flattened cross-section. The “observed” curve shown in Figure 3-3 indicates how much the compression diameter is reduced. The necessary percentage of squeeze should be applied to this corrected compression diameter, reducing the gland depth below the recommended dimensions shown in the standard design charts. Note: Figure 3-3 is valid for approximation purposes and even the majority of O-ring applications. However, more recent research has been done for the low stretch cases (i.e., 0 – 5%) where the observed values conform to a more complex hyperbolic function. For more information, refer to inPHorm seal design and material selection software. Extra stretch may be necessary when a non-standard bore or rod diameter is encountered. In male gland (piston type) assemblies of large diameter, the recommended stretch is so slight that the O-ring may simply sag out of the groove. There is then the danger of pinching if the O-ring enters the bore “blind,” i.e. in a location where the seal cannot be watched and manually guided into the bore. For large diameter assemblies of this kind, it is well to use an O-ring one size smaller than indicated, but then the gland depth must be reduced as indicated above because the stretch may approach five percent. Figure 3-4: Proper Designs for Installation of O-rings Proper Designs for Installation of O-rings Chamfer Hole Junction View A Enlarged or Undercut Bore (Preferred) Cylinder Bore 10° to 20° 10° to 20° Piston Rod (X Greater ThanY) Free O-ring Chamfer Angle 10° to 20° Chamfer to Serve as Shoe Horn X Y Direction of Installation Bore Cross Drilled Port Pinched O-ring See View "A" to Eliminate Sharp Edge Figure 3-3: Loss of Compression Diameter (W) Due to Stretch Free Diameter Free O-ring Compression Diameter Stretched O-ring Percent Reduction in Cross Section Diameter (Flattening) Percent of Diametral Stretch on O-ring Inside Diameter at Time of Assembly Loss of Compression Diameter (W) Due to Stretch 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 4 6 8 10 12 14 16 18 20 22 24 26 Observed Calculated The “observed” curve is reproduced by courtesy of the Research Laboratories of General Motors Corporation at the General Motors Technical Center in Warren, Michigan. This curve is based on a statistical analysis of a much larger volume of experimental data than has been available previously. In the stretched condition, an O-ring cross section is no longer circular. It is often necessary to compensate for the loss in squeeze resulting from the reduced “compression diameter.” Dimensional changes in the “free diameter” do not affect the seal. Empirical formulas for observed curve: 0 to 3% Inside Dia. Stretch: Y = -0.005 + 1.19X - 0.19X2 - 0.001X3 + 0.008X4 3 to 25% Inside Dia. Stretch: Y = .56 + .59X - .0046X2 Where X = percent stretch on inside diameter (i.e. for 5% stretch, X = 5) Y = percent reduction in cross section diameter. The calculated curve is based on the assumption that the O-ring section remains round and the volume does not change after stretching. Formula: Y = 100 1 - 10 100 + X ( ( 3-9O-Ring Applications Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com Parker O-Ring Handbook An assembled stretch greater than five percent is not recommended because the internal stress on the O-ring causes more rapid aging. Over five percent stretch may sometimes be used, however, if a shorter useful life is acceptable. Of the commonly used O-ring seal elastomers, the reduction in useful life is probably greatest with nitrile materials. Therefore, where high stretch is necessary, it is best to use ethylene propylene, fluorocarbon, polyurethane or neoprene, whichever material has the necessary resistance to the temperatures and fluids involved. 3.6 Squeeze The tendency of an O-ring to attempt to return to its original uncompressed shape when the cross-section is deflected is the basic reason why O-rings make such excellent seals. Obviously then, squeeze is a major consideration in O-ring seal design. In dynamic applications, the maximum recommended squeeze is approximately 16%, due to friction and wear considerations, though smaller cross-sections may be squeezed as much as 25%. When used as a static seal, the maximum recommended squeeze for most elastomers is 30%, though this amount may cause assembly problems in a radial squeeze seal design. In a face seal situation, however, a 30% squeeze is often beneficial because recovery is more complete in this range, and the seal may function at a somewhat lower temperature. There is a danger in squeezing much more than 30% since the extra stress induced may contribute to early seal deterioration. Somewhat higher squeeze may be used if the seal will not be exposed to high temperatures nor to fluids that tend to attack the elastomer and cause additional swell. The minimum squeeze for all seals, regardless of cross-section should be about .2 mm (.007 inches). The reason is that with a very light squeeze almost all elastomers quickly take 100% compression set. Figure 3-5 illustrates this lack of recovery when the squeeze is less than .1 mm (.005 inch). The three curves, representing three nitrile compounds, show very clearly that a good compression set resistant compound can be distinguished from a poor one only when the applied squeeze exceeds .1 mm (.005 inches). Most seal applications cannot tolerate a “no” or zero squeeze condition. Exceptions include low-pressure air valves, for which the floating pneumatic piston ring design is commonly used, and some rotary O-ring seal applications. See the Dynamic ORing Sealing, Section V, and Tables A6-6 and A6-7 for more information on pneumatic and rotary O-ring seal design. 3.7 Gland Fill The percentage of gland volume that an O-ring cross-section displaces in its confining gland is called “gland fill”. Most O-ring seal applications call for a gland fill of between 60% to 85% of the available volume with the optimum fill being 75% (or 25% void). The reason for the 60% to 85% range is because of potential tolerance stacking, O-ring volume swell and possible thermal expansion of the seal. It is essential to allow at least a 10% void in any elastomer sealing gland. 3.8 O-Ring Compression Force The force required to compress each linear inch of an O-ring seal depends principally on the shore hardness of the O-ring, its cross-section, and the amount of compression desired. Even if all these factors are the same, the compressive force per linear inch for two rings will still vary if the rings are made from different compounds or if their inside diameters are different. The anticipated load for a given installation is not fixed, but is a range of values. The values obtained from a large number of tests are expressed in the bar charts of Figures 2-4 through 2-8 in Section II. If the hardness of the compound is known quite accurately, the table for O-ring compression force, Table 2-3 may be used to determine which portion of the bar is most likely to apply. Increased service temperatures generally tend to soften elastomeric materials (at least at first). Yet the compression force decreases very little except for the hardest compounds. For instance, the compression force for O-rings in compound N0674-70 decreased only 10% as the temperature was increased from 24°C (75°F) to 126°C (258°F). In compound N0552-90 the compression force decrease was 22% through the same temperature range. Refer to Figure 3-6 for the following information: The dotted line indicates the approximate linear change in the cross section (W) of an O-ring when the gland prevents any change in the I.D. with shrinkage, or the O.D., with swell. Hence this curve indicates the change in the effective squeeze on an O-ring due to shrinkage or swell. Note that volumetric change may not be such a disadvantage as it appears at first glance. A volumetric shrinkage of six percent results in only three percent Figure 3-5: Compression Recovery of Three O-ring Compounds When Light Squeeze is Applied Compression Recovery of Three O-Ring Compounds When Light Squeeze is Applied Compression In. mm 0.1 0.005 100 75 50 25 0 0 0 0.3 0.010 0.4 0.015 Recovery After Compression of 70 Hours at 100°C (212°F) Recovery is Essentially Independent of Sample Thickness 0.5 0.020 Recovery Percent of Original Delection 3-10 Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com O-Ring Applications Parker O-Ring Handbook 3.9 Specific Applications 3.9.1 Automotive The types of elastomer compound required by this industry are numerous and the variety of applications quite extensive. The following examples can be viewed as a brief analysis of the problems found in the automotive industry. The demands made on an elastomer at high and low temperatures are even greater than normal while compatibility with new chemical additives which improve the physical properties of automotive fuels and oils, require continuous improvement in elastomeric compounds for automotive service. The selection of the proper O-ring compound depends on the temperature at the sealing interface and of the contact medium. Each group of elastomers have a working range of temperatures. The low temperature requirements for many automotive applications are often below the brittleness point for elastomers like FKM, ACM and NBR. However, static applications, leakage at low temperatures may not occur because of O-ring deformation and the high viscosity of the sealed medium. The critical temperature often is bridged when the seal warms quickly in service. 3.9.2 Engine See Table 3-9. General requirements: Temperature: -40°C to 125°C (-40°F to 250°F) (sometimes higher) Medium: Engine oil, cooling water, fuel, hot air and mixtures of these media Engine Applications Application Medium Temperature Range °C (°F) Compounds ASTM D1418 Parker Motor oil Oil filter SAEOils -35°C to 110°C (-31°F to 230°F) NBR N0674-70 -30°C to 120°C (-22°F to 248°F) NBR N0951-75 -25°C to 200°C (-13°F to 392°F) FKM V1164-75 -25°C to 150°C (-13°F to 392 °F) ACM AA150-70 Wet cylinders (Diesel) Water/ Oil -30°C to 100°C (-22°F to 212°F) NBR N0951-75 -25°C to 120°C (-13°F to 248°F) FKM V1164-70 Air-filter Air/Fuel -35°C to 90°C (-31°F to 194°F) NBR N0674-70 -60°C to 210°C (-76°F to 410°F) VMQ S1224-70 Table 3-9: Engine Applications 3.9.3 Brake System General requirements: Temperature: -40°C to 150°C (-40°F to 302°F) Medium: Synthetic brake fluid (Dot3, Dot4, Dot5) with glycol or glycol-ether base to Department of Transportion and SAE recommendations Compound: E0667-70, E1022-70 3.9.4 Fuel System Gasoline and diesel fuels are used in normal commercial vehicles. Fuels are more aggressive than mineral oils and cause higher swelling of the elastomer which increases with temperature. Swelling of an elastomer in fuel is, however, generally reversible when the absorbed fuel vaporizes completely. When parts of a compound are dissolved or leached out of the elastomer however, shrinkage takes place which is permanent. If a nitrile-based compound is required, a compound must be selected which contains minimum amounts of plasticisers, anti-aging or anti-ozone additives. By careful selection of the seal compound, the tendency to shrinkage or cold brittleness is avoided. Figure 3-6: O-ring Linear vs. Volume Change Relationship O-Ring Linear vs. Volume Change Relationship Linear Shrinkage Percent Volume Shrinkage Percent Linear Expansion — Percent Volume Swell — Percent 15 10 100 90 80 70 60 50 40 30 20 10 10 20 5 5 10 15 20 25 30 35 40 Fixed I.D. Free O-Ring Fixed O.D. linear shrinkage when the O-ring is confined in a gland. This represents a reduction of only .003" of squeeze on an O-ring having a .103" cross-section (W) dimension. The solid lines indicate linear change in both I.D. and cross-section for a free-state (unconfined) O-ring. 3-11O-Ring Applications Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com Parker O-Ring Handbook Volume Swell of Compounds Compound No. 47-071(2) N0497-70 N0674-70(2) V0747-75(2) V0834-70 TR-10 in air -40°F -23°F -15°F +5°F +5°F FUEL Unleaded gasoline 12% 14% 36% 1% 1% Unleaded +10% ethanol(3) 26% 24% 53% 5% 2% Unleaded +20% ethanol 24% 24% 56% 4% 5% Unleaded +10% methanol 35% 33% 66% 14% 16% Unleaded +20% methanol 32% 30% 67% 26% 36% (1) Volume swell of 2-214 O-ring immersed in the fuel for 70 hours at room temperature. (2) Stock standard compounds. Generally available off-the-shelf. (3) The “gasohol” mixture most commonly used in the United States consists of unleaded gasoline plus 10% ethanol (ethyl alcohol). Table 3-10: Volume Swell of Compounds 3.9.5 Fuels for Automobile Engines There are several automotive fuels on the market; gasoline (which can contain 10-20% ethanol), ethanol/E85, diesel and biodeisel are the most common. Parker is at the forefront in testing elastomer materials for use in traditional and alternative fuels. For the latest information and test data regarding this rapidly changing industry, please contact Parker’s O-Ring Division. The best rubber compound to use depends not only on the fuel itself, but also on the temperature range anticipated and the type of usage; i.e. whether in a static or a dynamic application. In automotive fuel applications, extremely high temperatures are not anticipated, but in northern climates, temperatures as low as -40°C (-40°F) or even -54°C (-65°F) are sometimes encountered. Most of the compounds recommended for use in fuel have rather poor low temperature capability in air, but in a fluid that swells them the low temperature capability improves. In studying the effects of volume swell on low temperature, it was found that for each percent of volume swell in a fuel, the low temperature capability (TR-10) was improved between 0.5°C and 1°C (1°F and 2°F). The TR-10 value is a good indicator of the low temperature limit of a dynamic seal or a static seal exposed to pulsating pressure. In a static steady pressure application, an O-ring will generally function to a temperature approximately 8°C (15°F) lower than the TR-10 temperature. The volume swell chart that follows, therefore, can be used to approximate the low temperature capability of a given compound in a given automotive fuel. The results will not be precise because the effect of volume swell on the TR-10 value is not precise, and also because the composition of the fuels themselves is not uniform. In static applications, even in most extreme volume cases, swell can sometimes be tolerated. An O-ring can swell only until it completely fills the cavity. Further increase in volume is not possible, regardless of how much volume swell is observed in a full immersion test. If the free state swell exceeds 50 percent, however, a radial squeeze assembly may be almost impossible to take apart because of the osmotic forces generated. In dynamic applications, volume swell up to 15 or 20 percent is usually acceptable, but higher values are likely to increase friction and reduce toughness and abrasion resistance to the point that use of the particular compound is no longer feasible. With these factors in mind, the data in Table 3-10 can be helpful in finding a suitable compound to use in a given automotive fuel application. 3.9.6 Transmission General requirements: Temperature: 90°C (158°F) (short periods up to 150°C) (302°F) Medium: Gear oil (reference oil SAE 90) For automatic transmission: Medium: ATF oil (Automatic Transmission Fluid) Compound: N0674-70, N0552-90, AA150-70, AE152-70 (Vamac), V1164-75, V0884-75 (brown) 3.9.7 Cooling and Heating Systems General requirements: Temperature: -40°C to 100°C (-40°F to 212°F) (short periods up to 120°C (257°F)) Medium: a) Water-glycol mixture 1:1 (with 1 to 2% corrosion retarding additives) Medium: b) Water-ethylene glycol mixture 1:1 (Prestone® antifreeze) Compound: E0803-70 Prestone® is a registered trademark of Prestone Products Corporation. 3-12 Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com O-Ring Applications Parker O-Ring Handbook Compound Recommendation for Refrigerants Fluorinated Hydrocarbons Refrigerant (R) ASTM D1418 Parker 11 NBR N0674-70 12 CR C0873-70 12 and ASTM oil no. 2 (mixed 50:50) FKM V1164-75 12 and Suniso 4G (mixed 50:50) FKM V1164-75 13 CR C0873-70 13 B1 CR C0873-70 14 CR C0873-70 21 CR C0873-70 22 CR C0873-70 22 and ASTM oil no. 2 (mixed 50:50) CR C0873-70 31 CR C0873-70 32 CR C0873-70 112 FKM V1164-75 113 CR C0873-70 114 CR C0873-70 114 B2 CR C0873-70 115 CR C0873-70 502 CR C0873-70 134a CR C0873-70 BF (R112) FKM V1164-75 C318 CR C0873-70 K-152a CR C0873-70 K-142b CR C0873-70 MF (R11) NBR N0674-70 PCA (R113) CR C0873-70 TF (R113) CR C0873-70 Table 3-11: Compound Recommendation for Refrigerants 3.9.8 Air Conditioning Automotive A/C units are almost exclusively charged with refrigerant R134a, whereas existing units are generally filled with the older (and now banned in US) R12 Freon refrigerant. Special oils are added to the refrigerant in order to lubricate the compressor: R134a systems use mostly polyalkylene glycol oils, whereas R12 systems employ mostly mineral oils. General requirements: Temperature: -40°C to 80°C (-40°F to 175°F) Medium: refrigerant R134a refrigerant R12 polyalkylene glycol oil mineral oil Compound: C0873-70, N1173-70 3.9.9 Power Steering Systems General requirements: Temperature: Up to 120°C (-40°F to 257°F) (short periods up to 150°C (302°F)) Medium: Power steering fluid Compound: N0674-70, N0552-90, AA150-70, AE152-70 (Vamac), V1164-75, V0884-75 (brown) Oils are preferred which tend to have a constant viscosity over a wide temperature range. These highly developed oils can be very aggressive. FKM or ACM based materials are often are preferred when high operating temperatures are involved. 3.9.10 Refrigeration and Air Conditioning Seals used in cooling systems should be fully compatible with the refrigerant. Refrigerants often are coded “R” and consist of fluids based on fluorinated and chlorinated hydrocarbons. Trade names, e.g. Freon, Frigen®, Kaltron® are used together with the type number. Examples: • R13 corresponds to Freon 13 and Kaltron 13 • R13 B1 corresponds to Freon 13 B1, Frigen 13 B1 and Kaltron 13 B1 Fire extinguishers are propelled with Halon R1301 corresponding to Freon 13 B1. Several of these refrigerants also are used as propellants in aerosol containers. Further information on compounds can be found in the Fluid Compatibility Tables in Section VII. See Table 3-11. 3.9.11 Food, Beverage and Potable Water The Food and Drug Administration (FDA) has established a list of rubber compounding ingredients which tests have indicated are neither toxic nor carcinogenic (cancer producing). Rubber compounds produced entirely from these ingredients and which also pass the FDA extraction tests are said to “meet the FDA requirements” per 21 CFR177.2600. The FDA does not approve rubber compounds. It is the responsibility of the manufacturer to compound food grade materials from the FDA list of ingredients and establish whether they pass the necessary extraction requirements. 3-A Sanitary Standards have been formulated by the United States Public Health Service, the International Association of Milk Food and Environmental Standards, and the Dairy and Food Industries Supply Association. A similar document, E-3A Sanitary Standards, was later formulated by this same group plus the United States Department of Agriculture and the Institute of American Poultry Industries. The 3-A standards are intended for elastomers to be used as product contact surfaces in dairy equipment, while the E-3A standards are intended for elastomers used as product contact surfaces in egg processing equipment. The requirements of the two specifications are essentially identical, the intent in each case being to determine whether rubber materials are capable of being cleaned and receiving an effective bactericidal treatment while still maintaining their physical properties after repeated applications of the cleaning process chemicals.
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O-Ring Kits Part Number Description Plastic Std. Kit E0515 Compound E0515-80 EPR 80 durometer O-rings per NAS 1613 rev. 2 in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit N0552 Compound N0552-90 NBR 90 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit N0674 Compound N0674-70 NBR 70 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit V0747 Compound V0747-75 FKM 75 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit V0884 Compound V0884-75 FKM (brown) 75 durometer O-rings in 37 popular AS568 sizes / 513 O-rings N1470 AS568 Kit #1 Compound N1470-70 NBR 70 durometer in 30 popular sizes / 382 O-rings N1470 Metric Kit #1 Compound N1470-70 NBR 70 durometer in 32 popular metric sizes / 372 O-rings N1490 Boss Kit Compound N1490-90 NBR 90 durometer in 20 standard tube fitting sizes Note: Boxes and plugs are available as separate items
3.1.6 Accessories 3.1.6.1 Extraction Tools These unique double-ended tools make life easier for those who have to frequently install or remove O-rings from hydraulic or pneumatic cylinders and equipment. They are available in brass or plastic with or without a convenient carrying case. 3.1.6.2 O-Ring Sizing Cone A unique measuring cone and circumference “Pi” tape provide quick and easy o-ring sizing information to determine the nearest standard Parker o-ring size. Please note: the cone and tape do not measure actual dimensions of a part and cannot be used for pass/fail inspections. See table 3-3 for part number information. 3.1.6.3 O-Ring Kits When part numbers are missing, seal dimensions are unknown, and the parts themselves are unavailable from the equipment OEM, these o-ring kits can save the day, not to mention hours of downtime. More than eight different standard kits give you a choice of compounds and o-ring sizes for a wide range of sealing applications. The end result? Multiple sealing solutions for the same cost as a single OEM replacement part. We’ll even build custom kits using any of our 200-plus compounds. Please see table 3-4 through table 3-7 for detailed kit information. O-Ring Extraction Tools and Cone Part Numbers Part Number Description Brass Extraction Kit Brass extraction pick and spat in plastic pouch Plastic O-ring Pick Plastic extraction pick Plastic Sizing Cone O-ring sizing kit Notes: Private labeling is available. Table 3-3: Extraction Tools and Cone Part Numbers O-Ring Kits Part Number Description Plastic Std. Kit E0515 Compound E0515-80 EPR 80 durometer O-rings per NAS 1613 rev. 2 in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit N0552 Compound N0552-90 NBR 90 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit N0674 Compound N0674-70 NBR 70 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit V0747 Compound V0747-75 FKM 75 durometer O-rings in 37 popular AS568 sizes / 513 O-rings Plastic Std. Kit V0884 Compound V0884-75 FKM (brown) 75 durometer O-rings in 37 popular AS568 sizes / 513 O-rings N1470 AS568 Kit #1 Compound N1470-70 NBR 70 durometer in 30 popular sizes / 382 O-rings N1470 Metric Kit #1 Compound N1470-70 NBR 70 durometer in 32 popular metric sizes / 372 O-rings N1490 Boss Kit Compound N1490-90 NBR 90 durometer in 20 standard tube fitting sizes Note: Boxes and plugs are available as separate items. Table 3-4: O-Ring Kits AS568 Kit #1 Sizes Size Dimensions Quantity 2-006 0.114 x .070 20 2-007 0.145 x .070 20 2-008 0.176 x .070 20 2-009 0.208 x .070 20 2-010 0.239 x .070 20 2-011 0.239 x .070 20 2-012 0.364 x .070 20 2-110 0.362 x .103 13 2-111 0.424 x .103 13 2-112 0.487 x .103 13 2-113 0.549 x .103 13 2-114 0.612 x .103 13 2-115 0.674 x .103 13 2-116 0.737 x .103 13 2-210 0.734 x .139 10 2-211 0.796 x .139 10 2-212 0.859 x .139 10 2-213 0.921 x .139 10 2-214 0.984 x .139 10 2-215 1.046 x .139 10 2-216 1.109 x .139 10 2-217 1.171 x .139 10 2-218 1.234 x .139 10 2-219 1.296 x .139 10 2-220 1.359 x .139 10 2-221 1.421 x .139 10 2-222 1.484 x .139 10 2-225 1.475 x .210 7 2-226 1.600 x .210 7 2-227 1.725 x .210 7 Table 3-5: AS568 Kit #1 Sizes Parker Metric Kit #1 Sizes Dimensions Quantity Dimensions Quantity 3.00 x 2.00 20 22.00 x 2.50 14 5.00 x 2.00 20 22.00 x 3.50 10 6.00 x 2.00 18 23.00 x 3.50 10 8.00 x 2.00 18 25.00 x 3.50 10 10.00 x 2.00 18 27.00 x 3.50 10 10.00 x 2.50 14 28.00 x 3.50 10 12.00 x 2.50 14 30.00 x 3.50 10 13.00 x 2.00 18 31.00 x 3.50 10 14.00 x 2.50 14 32.00 x 3.50 10 15.00 x 2.50 14 34.00 x 3.50 10 16.00 x 2.50 14 36.00 x 3.50 10 18.00 x 2.50 14 38.00 x 3.50 10 18.00 x 3.50 10 41.00 x 3.50 10 20.00 x 2.50 14 44.00 x 3.50 10 20.00 x 3.50 10 46.00 x 3.50 10 21.00 x 2.50 14 50.00 x 3.50 10 Table 3-6: Parker Metric Kit #1 Sizes 3-7O-Ring Applications Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com Parker O-Ring Handbook Effects of Cross Section Larger Section Smaller Section Dynamic Reciprocating Seals More stable Less stable More friction Less friction All Seals Requires larger supporting structure Requires less space — reduces weight Better compression set(1) Poorer compression set(1) Less volume swell in fluid More volume swell in fluid Less resistant to explosive decompression More resistant to explosive decompression Allows use of larger tolerances while still controlling squeeze adequately Requires closer tolerances to control squeeze. More likely to leak due to dirt, lint, scratches, etc. Less sensitive to dirt, lint, scratches, etc. Better physical properties(2) Poorer physical properties(2) Cost and availability are other factors to consider, and these would need to be determined for the particular sizes being considered. (1) Particularly true for nitrile and fluorocarbon elastomers. Doubtful for ethylene propylenes and silicones. (2) Applies to tensile and elongation of nitriles, elongation of fluorocarbons. Table 3-8: Effects of Cross Section 3.2 Cleanliness Cleanliness is vitally important to assure proper sealing action and long O-ring life. Every precaution must be taken to insure that all component parts are clean at time of assembly. Foreign particles — dust, dirt, metal chips, grit, etc.— in the gland may cause leakage and can damage the O-ring, reducing its life. It is equally important to maintain clean hydraulic fluids during the normal operation of dynamic seal systems. Costly shut downs necessitated by excessive seal wear and requiring early seal replacement may be prevented by the use of effective filters in the fluid power system as well as installing wiper rings on actuating rods exposed to external dust, dirt and other contaminants. 3.3 Assembly Assembly must be done with great care so that the O-ring is properly placed in the groove and is not damaged as the gland assembly is closed. Some of the more important design features to insure this are: 1. The I.D. stretch, as installed in the groove, should not be more than 5%. Excessive stretch will shorten the life of most O-ring materials. Also, see Figure 3-3 for data on the flattening effect produced by installation stretch. 2. The I.D. expansion needed to reach the groove during assembly ordinarily does not exceed 25-50% and should not exceed 50% of the ultimate elongation of the chosen compound. However, for small diameter O-rings, it may be necessary to exceed this rule of thumb. If so, sufficient time should be allowed for the O-ring to return to its normal diameter before closing the gland assembly. 3. The O-ring should not be twisted. Twisting during installation will most readily occur with O-rings having a large ratio of I.D. to cross-section diameter. Parker Boss Kit Sizes Size Dimensions Tube OD Quantity 3-901 0.185 x .056 3 ⁄32 10 3-902 0.239 x .064 1 ⁄8 10 3-903 0.301 x .064 3 ⁄16 10 3-904 0.351 x .072 ¼ 10 3-905 0.414 x .072 5 ⁄16 12 3-906 0.468 x .078 3 ⁄8 12 3-907 0.530 x .082 7 ⁄16 12 3-908 0.644 x .087 ½ 12 3-909 0.706 x .097 9 ⁄16 12 3-910 0.755 x .097 5 ⁄8 12 3-911 0.863 x .116 11⁄16 10 3-912 0.924 x .116 ¾ 10 3-913 0.986 x .116 13⁄16 10 3-914 1.047 x .116 7 ⁄8 10 3-916 1.171 x .116 1 10 3-918 1.355 x .116 11 ⁄8 10 3-920 1.475 x .118 1¼ 10 3-924 1.720 x .118 1½ 10 3-928 2.090 x .118 1¾ 10 3-932 2.337 x .118 2 10 Table 3-7: Parker Boss Kit Sizes 4. O-rings should never be forced over unprotected sharp corners, threads, keyways, slots, splines, ports, or other sharp edges. If impossible to avoid by proper design, then thimbles, supports, or other shielding arrangements must be used during assembly to prevent damage to the seal. See Figure 3-4. 5. Closure of the gland assembly must not pinch the O-ring at the groove corners. 6. Gland closure should be accomplished by straight longitudinal movement. Rotary or oscillatory motion is undesirable since it may cause bunching, misalignment and pinching or cutting of the seal. 3.4 Selecting the Best Cross-Section In designing an O-ring seal, there are usually several standard cross-section diameters available. There are a number of factors to consider in deciding which one to use, and some of these factors are somewhat contradictory. In a dynamic, reciprocating application, the choice is automatically narrowed because the design charts and tables do not include all the standard O-ring sizes. For any given piston or rod diameter, O-rings with smaller cross-section diameters are inherently less stable than larger cross-sections, tending to twist in the groove when reciprocating motion occurs. This leads to early O-ring spiral failure and leakage. The smaller cross-sections for each O-ring I.D. dimension are therefore omitted in the reciprocating seal design tables. Nevertheless, for many dynamic applications, there is still some choice as to cross-section, and the larger cross-sections will prove to be the more stable. Counterweighing this factor, is the reduced breakaway and running friction obtainable with a smaller cross-section O-ring. These and other factors to be considered are tabulated on Table 3-8. 3-8 Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com O-Ring Applications Parker O-Ring Handbook 3.5 Stretch When an O-ring is stretched, its cross-section is reduced and flattened. When the centerline diameter is stretched more than two or three percent, the gland depth must be reduced to retain the necessary squeeze on the reduced and flattened cross-section. The “observed” curve shown in Figure 3-3 indicates how much the compression diameter is reduced. The necessary percentage of squeeze should be applied to this corrected compression diameter, reducing the gland depth below the recommended dimensions shown in the standard design charts. Note: Figure 3-3 is valid for approximation purposes and even the majority of O-ring applications. However, more recent research has been done for the low stretch cases (i.e., 0 – 5%) where the observed values conform to a more complex hyperbolic function. For more information, refer to inPHorm seal design and material selection software. Extra stretch may be necessary when a non-standard bore or rod diameter is encountered. In male gland (piston type) assemblies of large diameter, the recommended stretch is so slight that the O-ring may simply sag out of the groove. There is then the danger of pinching if the O-ring enters the bore “blind,” i.e. in a location where the seal cannot be watched and manually guided into the bore. For large diameter assemblies of this kind, it is well to use an O-ring one size smaller than indicated, but then the gland depth must be reduced as indicated above because the stretch may approach five percent. Figure 3-4: Proper Designs for Installation of O-rings Proper Designs for Installation of O-rings Chamfer Hole Junction View A Enlarged or Undercut Bore (Preferred) Cylinder Bore 10° to 20° 10° to 20° Piston Rod (X Greater ThanY) Free O-ring Chamfer Angle 10° to 20° Chamfer to Serve as Shoe Horn X Y Direction of Installation Bore Cross Drilled Port Pinched O-ring See View "A" to Eliminate Sharp Edge Figure 3-3: Loss of Compression Diameter (W) Due to Stretch Free Diameter Free O-ring Compression Diameter Stretched O-ring Percent Reduction in Cross Section Diameter (Flattening) Percent of Diametral Stretch on O-ring Inside Diameter at Time of Assembly Loss of Compression Diameter (W) Due to Stretch 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 4 6 8 10 12 14 16 18 20 22 24 26 Observed Calculated The “observed” curve is reproduced by courtesy of the Research Laboratories of General Motors Corporation at the General Motors Technical Center in Warren, Michigan. This curve is based on a statistical analysis of a much larger volume of experimental data than has been available previously. In the stretched condition, an O-ring cross section is no longer circular. It is often necessary to compensate for the loss in squeeze resulting from the reduced “compression diameter.” Dimensional changes in the “free diameter” do not affect the seal. Empirical formulas for observed curve: 0 to 3% Inside Dia. Stretch: Y = -0.005 + 1.19X - 0.19X2 - 0.001X3 + 0.008X4 3 to 25% Inside Dia. Stretch: Y = .56 + .59X - .0046X2 Where X = percent stretch on inside diameter (i.e. for 5% stretch, X = 5) Y = percent reduction in cross section diameter. The calculated curve is based on the assumption that the O-ring section remains round and the volume does not change after stretching. Formula: Y = 100 1 - 10 100 + X ( ( 3-9O-Ring Applications Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com Parker O-Ring Handbook An assembled stretch greater than five percent is not recommended because the internal stress on the O-ring causes more rapid aging. Over five percent stretch may sometimes be used, however, if a shorter useful life is acceptable. Of the commonly used O-ring seal elastomers, the reduction in useful life is probably greatest with nitrile materials. Therefore, where high stretch is necessary, it is best to use ethylene propylene, fluorocarbon, polyurethane or neoprene, whichever material has the necessary resistance to the temperatures and fluids involved. 3.6 Squeeze The tendency of an O-ring to attempt to return to its original uncompressed shape when the cross-section is deflected is the basic reason why O-rings make such excellent seals. Obviously then, squeeze is a major consideration in O-ring seal design. In dynamic applications, the maximum recommended squeeze is approximately 16%, due to friction and wear considerations, though smaller cross-sections may be squeezed as much as 25%. When used as a static seal, the maximum recommended squeeze for most elastomers is 30%, though this amount may cause assembly problems in a radial squeeze seal design. In a face seal situation, however, a 30% squeeze is often beneficial because recovery is more complete in this range, and the seal may function at a somewhat lower temperature. There is a danger in squeezing much more than 30% since the extra stress induced may contribute to early seal deterioration. Somewhat higher squeeze may be used if the seal will not be exposed to high temperatures nor to fluids that tend to attack the elastomer and cause additional swell. The minimum squeeze for all seals, regardless of cross-section should be about .2 mm (.007 inches). The reason is that with a very light squeeze almost all elastomers quickly take 100% compression set. Figure 3-5 illustrates this lack of recovery when the squeeze is less than .1 mm (.005 inch). The three curves, representing three nitrile compounds, show very clearly that a good compression set resistant compound can be distinguished from a poor one only when the applied squeeze exceeds .1 mm (.005 inches). Most seal applications cannot tolerate a “no” or zero squeeze condition. Exceptions include low-pressure air valves, for which the floating pneumatic piston ring design is commonly used, and some rotary O-ring seal applications. See the Dynamic ORing Sealing, Section V, and Tables A6-6 and A6-7 for more information on pneumatic and rotary O-ring seal design. 3.7 Gland Fill The percentage of gland volume that an O-ring cross-section displaces in its confining gland is called “gland fill”. Most O-ring seal applications call for a gland fill of between 60% to 85% of the available volume with the optimum fill being 75% (or 25% void). The reason for the 60% to 85% range is because of potential tolerance stacking, O-ring volume swell and possible thermal expansion of the seal. It is essential to allow at least a 10% void in any elastomer sealing gland. 3.8 O-Ring Compression Force The force required to compress each linear inch of an O-ring seal depends principally on the shore hardness of the O-ring, its cross-section, and the amount of compression desired. Even if all these factors are the same, the compressive force per linear inch for two rings will still vary if the rings are made from different compounds or if their inside diameters are different. The anticipated load for a given installation is not fixed, but is a range of values. The values obtained from a large number of tests are expressed in the bar charts of Figures 2-4 through 2-8 in Section II. If the hardness of the compound is known quite accurately, the table for O-ring compression force, Table 2-3 may be used to determine which portion of the bar is most likely to apply. Increased service temperatures generally tend to soften elastomeric materials (at least at first). Yet the compression force decreases very little except for the hardest compounds. For instance, the compression force for O-rings in compound N0674-70 decreased only 10% as the temperature was increased from 24°C (75°F) to 126°C (258°F). In compound N0552-90 the compression force decrease was 22% through the same temperature range. Refer to Figure 3-6 for the following information: The dotted line indicates the approximate linear change in the cross section (W) of an O-ring when the gland prevents any change in the I.D. with shrinkage, or the O.D., with swell. Hence this curve indicates the change in the effective squeeze on an O-ring due to shrinkage or swell. Note that volumetric change may not be such a disadvantage as it appears at first glance. A volumetric shrinkage of six percent results in only three percent Figure 3-5: Compression Recovery of Three O-ring Compounds When Light Squeeze is Applied Compression Recovery of Three O-Ring Compounds When Light Squeeze is Applied Compression In. mm 0.1 0.005 100 75 50 25 0 0 0 0.3 0.010 0.4 0.015 Recovery After Compression of 70 Hours at 100°C (212°F) Recovery is Essentially Independent of Sample Thickness 0.5 0.020 Recovery Percent of Original Delection 3-10 Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com O-Ring Applications Parker O-Ring Handbook 3.9 Specific Applications 3.9.1 Automotive The types of elastomer compound required by this industry are numerous and the variety of applications quite extensive. The following examples can be viewed as a brief analysis of the problems found in the automotive industry. The demands made on an elastomer at high and low temperatures are even greater than normal while compatibility with new chemical additives which improve the physical properties of automotive fuels and oils, require continuous improvement in elastomeric compounds for automotive service. The selection of the proper O-ring compound depends on the temperature at the sealing interface and of the contact medium. Each group of elastomers have a working range of temperatures. The low temperature requirements for many automotive applications are often below the brittleness point for elastomers like FKM, ACM and NBR. However, static applications, leakage at low temperatures may not occur because of O-ring deformation and the high viscosity of the sealed medium. The critical temperature often is bridged when the seal warms quickly in service. 3.9.2 Engine See Table 3-9. General requirements: Temperature: -40°C to 125°C (-40°F to 250°F) (sometimes higher) Medium: Engine oil, cooling water, fuel, hot air and mixtures of these media Engine Applications Application Medium Temperature Range °C (°F) Compounds ASTM D1418 Parker Motor oil Oil filter SAEOils -35°C to 110°C (-31°F to 230°F) NBR N0674-70 -30°C to 120°C (-22°F to 248°F) NBR N0951-75 -25°C to 200°C (-13°F to 392°F) FKM V1164-75 -25°C to 150°C (-13°F to 392 °F) ACM AA150-70 Wet cylinders (Diesel) Water/ Oil -30°C to 100°C (-22°F to 212°F) NBR N0951-75 -25°C to 120°C (-13°F to 248°F) FKM V1164-70 Air-filter Air/Fuel -35°C to 90°C (-31°F to 194°F) NBR N0674-70 -60°C to 210°C (-76°F to 410°F) VMQ S1224-70 Table 3-9: Engine Applications 3.9.3 Brake System General requirements: Temperature: -40°C to 150°C (-40°F to 302°F) Medium: Synthetic brake fluid (Dot3, Dot4, Dot5) with glycol or glycol-ether base to Department of Transportion and SAE recommendations Compound: E0667-70, E1022-70 3.9.4 Fuel System Gasoline and diesel fuels are used in normal commercial vehicles. Fuels are more aggressive than mineral oils and cause higher swelling of the elastomer which increases with temperature. Swelling of an elastomer in fuel is, however, generally reversible when the absorbed fuel vaporizes completely. When parts of a compound are dissolved or leached out of the elastomer however, shrinkage takes place which is permanent. If a nitrile-based compound is required, a compound must be selected which contains minimum amounts of plasticisers, anti-aging or anti-ozone additives. By careful selection of the seal compound, the tendency to shrinkage or cold brittleness is avoided. Figure 3-6: O-ring Linear vs. Volume Change Relationship O-Ring Linear vs. Volume Change Relationship Linear Shrinkage Percent Volume Shrinkage Percent Linear Expansion — Percent Volume Swell — Percent 15 10 100 90 80 70 60 50 40 30 20 10 10 20 5 5 10 15 20 25 30 35 40 Fixed I.D. Free O-Ring Fixed O.D. linear shrinkage when the O-ring is confined in a gland. This represents a reduction of only .003" of squeeze on an O-ring having a .103" cross-section (W) dimension. The solid lines indicate linear change in both I.D. and cross-section for a free-state (unconfined) O-ring. 3-11O-Ring Applications Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com Parker O-Ring Handbook Volume Swell of Compounds Compound No. 47-071(2) N0497-70 N0674-70(2) V0747-75(2) V0834-70 TR-10 in air -40°F -23°F -15°F +5°F +5°F FUEL Unleaded gasoline 12% 14% 36% 1% 1% Unleaded +10% ethanol(3) 26% 24% 53% 5% 2% Unleaded +20% ethanol 24% 24% 56% 4% 5% Unleaded +10% methanol 35% 33% 66% 14% 16% Unleaded +20% methanol 32% 30% 67% 26% 36% (1) Volume swell of 2-214 O-ring immersed in the fuel for 70 hours at room temperature. (2) Stock standard compounds. Generally available off-the-shelf. (3) The “gasohol” mixture most commonly used in the United States consists of unleaded gasoline plus 10% ethanol (ethyl alcohol). Table 3-10: Volume Swell of Compounds 3.9.5 Fuels for Automobile Engines There are several automotive fuels on the market; gasoline (which can contain 10-20% ethanol), ethanol/E85, diesel and biodeisel are the most common. Parker is at the forefront in testing elastomer materials for use in traditional and alternative fuels. For the latest information and test data regarding this rapidly changing industry, please contact Parker’s O-Ring Division. The best rubber compound to use depends not only on the fuel itself, but also on the temperature range anticipated and the type of usage; i.e. whether in a static or a dynamic application. In automotive fuel applications, extremely high temperatures are not anticipated, but in northern climates, temperatures as low as -40°C (-40°F) or even -54°C (-65°F) are sometimes encountered. Most of the compounds recommended for use in fuel have rather poor low temperature capability in air, but in a fluid that swells them the low temperature capability improves. In studying the effects of volume swell on low temperature, it was found that for each percent of volume swell in a fuel, the low temperature capability (TR-10) was improved between 0.5°C and 1°C (1°F and 2°F). The TR-10 value is a good indicator of the low temperature limit of a dynamic seal or a static seal exposed to pulsating pressure. In a static steady pressure application, an O-ring will generally function to a temperature approximately 8°C (15°F) lower than the TR-10 temperature. The volume swell chart that follows, therefore, can be used to approximate the low temperature capability of a given compound in a given automotive fuel. The results will not be precise because the effect of volume swell on the TR-10 value is not precise, and also because the composition of the fuels themselves is not uniform. In static applications, even in most extreme volume cases, swell can sometimes be tolerated. An O-ring can swell only until it completely fills the cavity. Further increase in volume is not possible, regardless of how much volume swell is observed in a full immersion test. If the free state swell exceeds 50 percent, however, a radial squeeze assembly may be almost impossible to take apart because of the osmotic forces generated. In dynamic applications, volume swell up to 15 or 20 percent is usually acceptable, but higher values are likely to increase friction and reduce toughness and abrasion resistance to the point that use of the particular compound is no longer feasible. With these factors in mind, the data in Table 3-10 can be helpful in finding a suitable compound to use in a given automotive fuel application. 3.9.6 Transmission General requirements: Temperature: 90°C (158°F) (short periods up to 150°C) (302°F) Medium: Gear oil (reference oil SAE 90) For automatic transmission: Medium: ATF oil (Automatic Transmission Fluid) Compound: N0674-70, N0552-90, AA150-70, AE152-70 (Vamac), V1164-75, V0884-75 (brown) 3.9.7 Cooling and Heating Systems General requirements: Temperature: -40°C to 100°C (-40°F to 212°F) (short periods up to 120°C (257°F)) Medium: a) Water-glycol mixture 1:1 (with 1 to 2% corrosion retarding additives) Medium: b) Water-ethylene glycol mixture 1:1 (Prestone® antifreeze) Compound: E0803-70 Prestone® is a registered trademark of Prestone Products Corporation. 3-12 Parker Hannifin Corporation • O-Ring Division 2360 Palumbo Drive, Lexington, KY 40509 Phone: (859) 269-2351 • Fax: (859) 335-5128 www.parkerorings.com O-Ring Applications Parker O-Ring Handbook Compound Recommendation for Refrigerants Fluorinated Hydrocarbons Refrigerant (R) ASTM D1418 Parker 11 NBR N0674-70 12 CR C0873-70 12 and ASTM oil no. 2 (mixed 50:50) FKM V1164-75 12 and Suniso 4G (mixed 50:50) FKM V1164-75 13 CR C0873-70 13 B1 CR C0873-70 14 CR C0873-70 21 CR C0873-70 22 CR C0873-70 22 and ASTM oil no. 2 (mixed 50:50) CR C0873-70 31 CR C0873-70 32 CR C0873-70 112 FKM V1164-75 113 CR C0873-70 114 CR C0873-70 114 B2 CR C0873-70 115 CR C0873-70 502 CR C0873-70 134a CR C0873-70 BF (R112) FKM V1164-75 C318 CR C0873-70 K-152a CR C0873-70 K-142b CR C0873-70 MF (R11) NBR N0674-70 PCA (R113) CR C0873-70 TF (R113) CR C0873-70 Table 3-11: Compound Recommendation for Refrigerants 3.9.8 Air Conditioning Automotive A/C units are almost exclusively charged with refrigerant R134a, whereas existing units are generally filled with the older (and now banned in US) R12 Freon refrigerant. Special oils are added to the refrigerant in order to lubricate the compressor: R134a systems use mostly polyalkylene glycol oils, whereas R12 systems employ mostly mineral oils. General requirements: Temperature: -40°C to 80°C (-40°F to 175°F) Medium: refrigerant R134a refrigerant R12 polyalkylene glycol oil mineral oil Compound: C0873-70, N1173-70 3.9.9 Power Steering Systems General requirements: Temperature: Up to 120°C (-40°F to 257°F) (short periods up to 150°C (302°F)) Medium: Power steering fluid Compound: N0674-70, N0552-90, AA150-70, AE152-70 (Vamac), V1164-75, V0884-75 (brown) Oils are preferred which tend to have a constant viscosity over a wide temperature range. These highly developed oils can be very aggressive. FKM or ACM based materials are often are preferred when high operating temperatures are involved. 3.9.10 Refrigeration and Air Conditioning Seals used in cooling systems should be fully compatible with the refrigerant. Refrigerants often are coded “R” and consist of fluids based on fluorinated and chlorinated hydrocarbons. Trade names, e.g. Freon, Frigen®, Kaltron® are used together with the type number. Examples: • R13 corresponds to Freon 13 and Kaltron 13 • R13 B1 corresponds to Freon 13 B1, Frigen 13 B1 and Kaltron 13 B1 Fire extinguishers are propelled with Halon R1301 corresponding to Freon 13 B1. Several of these refrigerants also are used as propellants in aerosol containers. Further information on compounds can be found in the Fluid Compatibility Tables in Section VII. See Table 3-11. 3.9.11 Food, Beverage and Potable Water The Food and Drug Administration (FDA) has established a list of rubber compounding ingredients which tests have indicated are neither toxic nor carcinogenic (cancer producing). Rubber compounds produced entirely from these ingredients and which also pass the FDA extraction tests are said to “meet the FDA requirements” per 21 CFR177.2600. The FDA does not approve rubber compounds. It is the responsibility of the manufacturer to compound food grade materials from the FDA list of ingredients and establish whether they pass the necessary extraction requirements. 3-A Sanitary Standards have been formulated by the United States Public Health Service, the International Association of Milk Food and Environmental Standards, and the Dairy and Food Industries Supply Association. A similar document, E-3A Sanitary Standards, was later formulated by this same group plus the United States Department of Agriculture and the Institute of American Poultry Industries. The 3-A standards are intended for elastomers to be used as product contact surfaces in dairy equipment, while the E-3A standards are intended for elastomers used as product contact surfaces in egg processing equipment. The requirements of the two specifications are essentially identical, the intent in each case being to determine whether rubber materials are capable of being cleaned and receiving an effective bactericidal treatment while still maintaining their physical properties after repeated applications of the cleaning process chemicals.
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