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Glossary (continued)

f. Proof Pressure or Test Pressure

 

– The maximum internal pressure 

which a hose can be subjected to without either deforming the 

corrugations, or exceeding 50 percent of the burst pressure. 

When a hose assembly is tested above 50 percent of its burst 

pressure, there often is a permanent change in the overall 

length of the assembly, which may be undesirable for certain 

applications.

g. PSIA

 –  Pounds per square inch absolute.

h. PSIG

 – Pounds per square inch gauge.

i.  Pulsating Pressure

 – A rapid change in pressure above and below 

the normal base pressure, usually associated with reciprocating 

type pumps. This pulsating pressure can cause excessive wear 

between the braid and the tops of the hose corrugations.

j. Shock Pressure

 

– A sudden increase of pressure in hydraulic or 

pneumatic system, which produces a shock wave. This shock 

can cause severe permanent deformation of the corrugations 

in a hose as well as rapid failure of the assembly due to metal 

fatigue.

k. Static Pressure

 – A non-changing constant pressure.

l. Working Pressure

- The pressure, usually internal, but sometimes 

external, imposed on a hose during operating conditions.

Profile:

 Used in reference to the contour rolled into strip during 

the process of manufacturing stripwound hose, or the finished 

shape of a corrugation; formed from a tube by either the “bump-

out”, “sink” or roll forming processes, used in making  

corrugated hose.

Random Motion:

 The non-cyclic uncontrolled motion of a  

metal hose, such as occurs in manual handling.

Reusable Fitting:

 (See Mechanical Fitting)

Safety Factor:

 The relationship of working pressure to  

burst pressure.

Scale:

 Generally refers to the oxide in a hose assembly  

brought about by surface conditions or welding. An oxide.

Seamless:

 Used in reference to a corrugated metal hose made 

from a base tube that does not have a longitudinal seam as in the 

case of a butt welded or lap welded tube.

Squirm:

 A form of failure in which the hose is deformed into an 

“S” or “U” bend as the result of excessive internal pressure being 

applied or unbraided corrugated hose which has been axially 

compressed, loosening the braid, while the hose is pressurized. 

This is particularly true with long lengths of braided hose 

subjected to manual or mechanical handling.

Strand(s):

 Individual groups of wires in a braid. Each group is 

supplies from a separate carrier in the braiding machine. 

Stress Corrosion: 

A form of corrosion in stainless steel normally 

associated with chlorides.

Tig Weld: 

The tungsten insert gas welding process sometimes 

referred to as shielded arc. The common trade name is heliarc.

Traveling Loop:

 A general classification of bending, whereinthe 

hose is installed to a U-shaped configuration.
 

1.  Class A Loop

 – An application wherein the radius 

remains constant and one end of the hose moves 

parallel to the other end of the hose.

 

2. Class B Loop

 – A condition wherein a hose is installed 

in a U-shaped configuration and the ends move 

perpendicular to each other so as to enlarge or 

decrease the width of the loop.

Torque (Torsion):

 A force that produces, or tends to produce, 

rotation of or torsion through one end of a hose assembly while 

the other end is fixed.

 

Velocity: 

The speed at which the medium flows through the hose, 

usually specified in feet per second.

Velocity Resonance:

 The sympathetic vibration of convolutions 

due to buffeting of high velocity gas or air flow. 

Vibration:

 Low amplitude motion occurring at high frequency.

Welding: 

The process of localized join of two or more metallic 

components by means of heating their surfaces to a state of 

fusion, or by fusion with the use of additional filler materials. 

FOR MORE INFORMATION, VISIT

  

WWW.PENFLEX.COM

Notes: