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Flashcards in Fluid Conductors Deck (38)
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What does the term “fluid conductors” mean in relation to a hydraulic system?

The tubing or piping and fittings used to connect the various hydraulic system units.


What is the most important characteristic of “fluid Conductors”?

Efficiency is the most important characteristic of fluid conductors.


For maximum efficiency, “fluid conductors” should have what two characteristics?

In order to assure maximum efficiency, the fluid conductors should be clean, leak-proof, and have streamlined flow.


Name four factors that may cause turbulent flow in “fluid conductors”.

These include the velocity of the hydraulic system, friction, internal obstructions, and sharp turns in the fluid line.


Name three negative results of turbulent flow.

Excessive Pressure Drop
Increased Power Consumption
Increased Oil Temperature


What is the preferred “fluid conductor” material?

The most preferred material for lubricant conductors is SAE 1010 stainless steel tubing.


Where are flexible lines necessary?

It is needed where units must be free to move relative to each other.


What is flexible hose normally made of?

Stainless steel wire over reinforced synthetic rubber tube and covered by synthetic rubber.


Name the three grades of flexible hose.

The three flexible hose grades are : low pressure, medium pressure, and high pressure.


Name five precautions to follow when using flexible hose.

1. Do not twist or place the hose in axial torsion.
2. Bend the hose in one plane only.
3. Use the proper fittings and adapters to relieve excessive strain.
4. Provide sufficient slack to compensate for changes in length and working conditions.
5. Avoid any sharp and/or excessive bends.
Page 57


Name four types of fittings used in industrial hydraulic systems.

1. Flared tube fitting
2. Flareless tube fitting
3. Socket welded fitting
4. Screwed fitting


How much straight length of tube must be allowed from the end of the tube to the start of the bend when installing hydraulic tubing?

twice the length of the fitting nut


Name four possible problems that can be avoided by the use of tube bending equipment.

kinks, flattened bends, wrinkles, and breakage


Why is it important to use as few fittings as possible?

I saves money, reduces installation time, reduces hydraulic shock load, while minimizing the possible leak sites.


What can be done to reduce the possibility of tubing fatigue?

Tubing fatigue can be reduced:
1. Support long tubing runs with brackets or clips
2. Bolt down all parts installed on tube lines, (i.e. heavy fittings, valves, etc.)


Name five methods of cleaning pipes, tubes and fittings prior to assembly of a hydraulic system.

1. Use boiler tube wire brush
2. Use commercial pipe cleaning apparatus
3. Ream inside edges of tubing & pipe after cutting to remove burrs
4. Sandblast short pieces of pipe and fittings
5. Pickle long pieces of pipe, or pipe with complex bends


When filling a hydraulic system with hydraulic fluid, what mesh screen is recommended?

120 mesh screen (120 squares per inch)


How can air in hydraulic lines be eliminated?

Cycle the system while it is not under load. Bleed air until no bubbles are apparent. Keep system properly vented. Gradually bring the system up to temperature to slowly release dissolved air. Check for sources of air ingression. Eliminate contaminants that may affect air release.


What type of chemical is used in pickling?

An inhibited acid solution


What must be done to stop the pickling process?

Rinse the parts in cold running water and neutralize the pickling acid


When the pickling process is completed, what is the next step?

Protect the pickled parts from rust.


Why does the burst pressure of a Schedule 40 pipe decrease as the ID increases?

OD (outside diameter) stays constant
Wall thickness decreases


What are three primary advantages of tubing over piping?

Less connections and leaks Lower pressure loss
High Pressure Lower cost
Neater Installations
Can bend tubing
Page 56


What three ways are there for conveying hydraulic fluid?
List three types of fluid conductors.

1. piping
2. tubing
3. hose
Page 56


A properly designed piping system will have feed lines operating at _______ to _______ FPS, return lines at ______ to ______ FPS, and suction lines to the pump at ______ to ______ FPS.

feed lines 5 to 7 FPS
return lines 1to 3 FPS
pump lines 3 to 5 FPS


Piping selection is based on ___________, which is measured in FPS.

Flow velocity


Piping must be large enough to prevent ________ in the pump suction lines.



Would you increase or decrease the velocity of a hydraulic fluid to reduce turbulent flow?

In order to decrease turbulence, decrease the velocity of the fluid.


How can the number of fittings be reduced?

By utilizing bends in tubing where practical.


When measuring pipe, regardless of schedule number, what dimension of the pipe is consistent?

The OD (outer diameter)