Application Engineering Training-液压软管接头选型与失效分析

1、Workshop components for fluid handling system.Specma Hydraulic, Shanghai20012-09-03Agenda: Identifying different ports in valves, engine etc. Identifying different sealing systems on hose and pipe Assembly instructions and recommendations. Different hose constructions Parameters that effect the life

2、 length of the hose. Parameters to think about during hose installation. Checkpoints at service on machine in field. Identifying different ports in valves, engine etc.Bounded sealCopper sealingCutting edgeO-ringED sealing (soft sealing)O-ring with retaining ringDifferent type of sealing systemsBound

3、ed sealBounded seal is used between the adapter and the portCopper sealingCopper ring is used between the adapter and the portCutting edgeA sharp edge on the adapter is cutting into the surface of the port to reach the sealing.O-ringStandard O-ring is used to create the sealing. A chamber in the por

4、t is creating the necessary stability.ED sealing (soft sealing)A profiled soft sealing is adapted in a groove on the adapter.O-ring with retaining ringThe retaining ring is used as a support ring to make the same effect as the chamber and ED-sealing. A standard O-ring is used.Conical sealing, BSPT/

5、NPTFThe sealing is made by tighten the adapter until the leakage is stopping. This solution should not be used on new installations.Bounded sealCopper sealingCutting edgeO-ringED sealing (soft sealing)O-ring with retaining ringDifferent type of sealing systemsG (BSP thread) 60 sealing cone (BS)Metri

6、c thread 24 sealing cone (DIN)UNF thread JIC 37 sealing cone (SAE,ISO) UNF thread ORFS 90sealing cone (SAE,ISO)Flange 3000 and 6000 psi Code 61 and 62 (SAE)Sealing systems for hose and pipe G (BSP thread) 60 sealing cone (BS). The sealing cone exist with both ball formed cone and straight 60 cone, t

7、o be assembled with pipe you need to use a welded or brazed cone. Metric thread 24 sealing cone (DIN), can be used with cutting ring both on pipe and hose fitting. Metric thread 24 sealing cone (DIN), For a safer application a cone with O-ring can be used, together with a formed cone on the pipe you

8、 get a very secure installation. UNF thread JIC 37 sealing cone (SAE,ISO). Metallic sealing zone. Very common used world wide, easy handling with flaring of pipe. UNF thread ORFS 90sealing cone (SAE,ISO). Soft sealing zone, very common used world wide, higher demand on flaring equipment.Flange 3000

9、and 6000 psi. Code 61 and 62 (SAE).G (BSP thread) 60 sealing cone (BS)Metric thread 24 sealing cone (DIN)UNF thread JIC 37 sealing cone (SAE,ISO) UNF thread ORFS 90sealing cone (SAE,ISO)Flange 3000 and 6000 psi Code 61 and 62 (SAE)Sealing systems for hose and pipeExampels of various hose fittingsUNF

10、/JICStraight femaleDifferent dropheightsThread3/16 ” ” ” ”5/16 ”3/8 ”3/8 ”3/8 ” ” ”5/8 ”5/8 ”3/4 ”3/4 ”3/4 ”1 ”1 1/4 ”1 ”2 ”7/16 -20-209/16-18-167/8-1411/16-1215/16-1215/8-1217/8-1221/2-12Angel 90 femaleStraight maleAngel 45 femaleDifferent typeof nutsHoseIDDifferent hose insertdepending onpressureA

11、ssembly instructions and recommendations.Parameters that effect the choice of hoseSizeMedia ApplicationTemperatureWorking pressureDifferent hose constructionInner tubeReinforcementCoverDifferent hose constructionReinforcementTextile + helix spiralBraidedSpiralDifferent hose constructionBraided reinf

12、orcementFlexibleLight weight / easy to assembleSpiral reinforcementHigh resistance against pressurePressure peaksSpiral- or braided reinforcementDifferent hose construction Parameters that effect the life length of the hose. TwistingExperience shows that life length is reduced with up to 90% if the

13、hose is twisted with 7 degrees during installation. Parameters that effect the life length of the hose. Temperature Parameters that effect the life length of the hose. Different rubber compound is used to create hoses that are suitable for different temperature ranges. The numbers above are to be se

14、en as guidelines.Temperature5093100110Life length factor1,00,60,450,25Working pressure Parameters that effect the life length of the hose. Working pressure% of stated working pressure100133150175Life length factor1,00,40,250,1Bending radius Parameters that effect the life length of the hose. % of st

15、ated bending radius100806040Life length factor1,00,80,60,3Change in lengthWhen a hose is under pressure, the length ofthe hose can change between -2% up too+6%. Ex. A hose that is 2 meters (6,5 feet) atinstallation can be between 4 cm (1,57 inch)shorter up to 12 cm (4,72 inch) longer. Parameters tha

16、t effect the life length of the hose. Straight hose out of the fitting As a principle we shall always try to have thefirst part of the hose straight after the ferrule.The length of this part should be 4 times theinner diameter of the hose. Experience shows that if you decrease thislength by 50% the

17、life length will be up to 20%shorter. Hoses that is bended directly after theferrule has up to 40% shorter life length. Parameters that effect the life length of the hose. Cleanliness Parameters that effect the life length of the hose. The cleanliness level inside the hose effect the life length of

18、the hole system.Parameters to think about during hose installation.On most of Specma Hydraulics hoses you can use the marking line on the hose to check that you have avoided to built in any twisting in the application.To avoid the twisting is, as you know, very important for the life length of the h

19、ose assembly.RightWrongParameters to think about during hose installation.Twisting will give room between the wires in thereinforcement. This will result in leakage.Parameters to think about during hose installation.Avoid to short hose length! Correct adapted hose length give you an better installat

20、ion that is easier to install and gives a longer life length.RightWrongParameters to think about during hose installation.Install the hose with a minimum of curves. The example above shows how you can reduce the numbers of curves from 3 to 1 and 2 to1 by using 90 fittings instead of straight fitting

21、s. This also gives the effect that you get a better bending radius on the curve that are remaining.RightWrongParameters to think about during hose installation.RightWrongUse correct type of fitting to avoid unnecessary curves on the hose.This will result in less abrasion and cleaner installation.Rig

22、htWrongParameters to think about during hose installation.Experience from Specma Hydraulics test facilitiesCheckpoints at service on machine in field.Cracks on hose cover Twisted hoseVolumetric change of inner tubeBubble on outer coverCrushed hoseCorrosion on hose fittingFerrule crimping errorsAbras

23、ionBurst on hoseBurst close to fittingLeakage in sealing areaLeakage between hose and ferruleFitting separated from hoseCheckpoints at service on machine in field.AbrasionContinuesly abrasion Checkpoints at service on machine in field.Burst on hosePressure peaksTight curvesExhaustion during flexing.

24、Over bendingCrushingTwistingCheckpoints at service on machine in field.Burst close to fittingTo short hose lengthExhaustion during flexing.Incorrect crimping of ferruleWrong ferruleCheckpoints at service on machine in field.Leakage in sealing areaWrong O-ringCracked O-ringDamaged thread or sealing s

25、urfaceWrong fittingWrong torqueWrong adapterCheckpoints at service on machine in field.Leakage between hose and ferruleIncorrect crimping of ferruleVibrationsTo short hoseDuring flexingTemperatureCheckpoints at service on machine in field.Fitting separated from hoseIncorrect crimping of ferruleWrong

26、 hose insertTemperaturePressurePressure peaksTo short hose lengthCheckpoints at service on machine in field.Cracks on hose coverHeat radiationOzoneTo high temperature on mediaFlexing with very low temperatures. (-55 deg C)Checkpoints at service on machine in field.Twisted hoseCheckpoints at service on machine in field.Experience shows that life length is reduced with up to 90% if the ho