IPT Section 3 - hydraulics Flashcards
What type of pipe finish is preferred for hydraulic systems?
- pickled and oiled
- pickled only
At what size does NPS refer to outside diameter of the pipe?
- above 12”
True or false
As the wall thickness of the pipe changes, the inside diameter changes.
- true
True or false
The wall thickness of 10” schedule 40 pipe is identical to 10” standard pipe.
- true
True or false
The wall thickness of 10” schedule 80 pipe is identical to 10” extra heavy pipe
- false
- identical up to 8”
What is the corresponding schedule number for double extra heavy pipe?
- there is no corresponding schedule number
What is the recommended maximum pressure for screw thread pipe joints?
- 2500 PSI
List 3 situations where welded pipe joints would be preferred over threaded joints
- high pressures
- vibration present
- oil leaks not tolerated
- large pipe diameter
What are the three pressure designations for forged steel fittings?
- class 2000
- class 3000
- class 6000
True or false
The American National Standards Taper Pipe Thread (NPT) has a 1 in 16 (3/4” per foot) taper on the diameter and a 60° thread form
- true
True or false
All pipe threads have the same number of threads per inch.
- false
How does NPTF thread differ from the NPT thread?
- same form and dimensions as NPT thread
- the truncation of the crests and roots is changed to ensure spiral clearance between the threads is eliminated
Why should a thread sealant be used with the NPTF thread?
- anti-galling purposes (lubrication) between male and female threads
Which type of reamer should be used in a power vise to remove internal burrs after cutting a pipe off to length?
- straight fluted reamer
True or false
The spiral reamer can be used to remove external burrs
- false
- must be filed or ground
Over-tightening pipe threads in a housing
- may split or crack the housing
Tubing is sized according to which diameter?
- outside diameter
True or false
The wall thickness of tubing is specified by a schedule number similar to iron pipe.
- false
True or false
Tubing sized as -12 would be 1-1/2” tubing
- false
True or false
Carbon steel is the only material available for tubing
- false
True or false
When using flareless type fittings it is important that the tubing is soft relative to the fitting material
- true
True or false
NPT threads are used when the tubing is to be threaded
- false
When using flared fittings: when is a double flare used?
- when using thing wall tubing
True or false
The 37° flare is the standard angle used for hydraulic tubing
- true
List three advantages that flexible hydraulic hose has over rigid connectors:
- simple to route and set in place
- can withstand vibration
- no problems with thermal expansion or contration
- dampens hydraulic shock
List the three main components of flexible hose
- inner tube
- reinforcement
- outer protective cover
For a given size, what determines the pressure rating of hydraulic hose?
- the reinforcement (+diameter)
True or false
The swaged on type of hydraulic hose end is not reusable
- true
True or false
The dash number used to size hydraulic flexible hose refers to the inside diameter of the hose for most hose types
- true
A -5 flexible hydraulic hose is what size in inches?
- 5/16”
A 1-1/4” hydraulic hose is what dash size?
- -20
True or false
For a specific reinforcement, the working pressure of hydraulic hose becomes less as the size increases
- true
As a hose is pressurized its length will:
- become shorter and longer
