Hoses and Couplers Session 11

Three materials that are used to make hydraulic lines zHoses -- flexible zPipes -- thicker than tubing, can be threaded zTubing -- thinner can be bent easy

State five advantages of flexible hoses zFlexibility zEasier to route zAbsorb vibration zWithstand Pressure surges zLess noisy

Identify the parts of flexible hoses zOuter cover-- protects the reinforcement and inner layer. Temperature resistant and UV light zReinforcement Layers-- reinforces hose, cloth, wire and nylon zInner Tube-- resistant to heat and corrosion flexible

Hose rating or selection based on ASE Standards zInside Diameter zOutside Diameter zMaximum Operating Pressure zMinimum burst pressure zTemperature limits

Describe how to select hoses zKnow the GPM of the system to determine the size of the hose zKnow pressure expectations zKnow temperature expectations for the system zCompatibility of hose to fluid zCost is less on smaller diameter hoses zIf you want more pressure in a big hose have to be reinforced better

List the four major types of hoses zFabric braid zSingle wire braid zDouble wire braid zSpiral Braid

Hose Rating by Size zWhich will withstand more pressure? y ___ 3/8 inch double wire braid or y ___ 1 inch double wire braid Why ?

Causes of hose failure zCracks and splits--old age--sunlight zpinhole leaks zincorrect hose length zimproper installation zwrong type of hose zwrong fitting--leaks zrubbing zheat ztwisting ztoo light Note: You may need to find more details about each of these in the text.

Describe how to properly install hoses zTaut hose-- allow some slack. Hoses that are stretched will fail sooner than correctly installed hoses zLoops-- used angled couplers to prevent long loops. The correct coupler make installation neater and reduces the length of hose required

zTwists -- Twist cause couplers to loosen and hoses to weaken as twisted hoses flex during operation zRubbing -- Use clamps or brackets to hold hoses away from sharp edges and moving parts. Hose guards of wire spring or flat armor may be necessary zHeat -- Route hydraulic hoses away from hot spots, such as exhaust pipes and exhaust manifolds. If a hose cannot be moved away from heat, insulate the hose with shielding ….install hoses

zSharp bend-- the minimum bend radius depends on the hose construction diameter and the pressure. At low pressure, the diameter can be smaller than the same hose and or higher pressure. Reroute the hose or use angle fittings rather than make sharp bends. Allow slack for freedom of movements, but do not allow kinks and loops ….install hoses

What are the six standard sealing methods? zText page 11-11

What are the flareless fittings? zPage of the text

What are the five basis types fo quick couples? zPage of your text

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