Installation &Maintenance
327
Service Life Factors
Hose and hose assemblies have a finite life. There are a number of factors that will reduce hose life. Consideration should be given to the following factors.
1.
Operating Pressure – The maximum operating pressure within
the hose should not exceed the recommended working pressure
as specified by Continental ContiTech as shown in the catalog
specifications. Hose selection must be made so that the recommended
maximum operating pressure is equal to or greater than the system
pressure. Burst pressure, which is four times the working pressure,
should not be used as the operating pressure of the hose. Exposing the
hose to pressures higher than the working pressure is dangerous and
will shorten hose life.
2.
Exposing the hose to a surge pressure, above the working pressure of
the hose, will shorten hose life. If surges are severe, select a hose with a
higher recommended working pressure.
3.
Burst Pressure – The burst pressure should never be considered in a
hydraulic system design. The burst pressure is for test purposes only.
Burst pressure is detrimental to the hose.
4.
Operating Temperatures – High heat conditions may have an adverse
affect on hose due to the degradation of the rubber and the affect on
fitting retention. Continuous use at or above the maximum operating
temperature of the hose will cause deterioration of the tube, cover and
reinforcement, reducing the hose life. Care should be taken to ensure
that fluid and ambient temperatures, both static and transient, do not
exceed the limitations of the hose. It is important to operate a hose
assembly within the specified temperature range of the specific hose.
5.
Bend Radius – Flexing the hose to less than its recommended
minimum bend radius will decrease hose life. Optimize routing to
minimize inherent problems.
6.
Excessive external forces such as flexing, twisting or kinking will reduce
hose life. Use the correct fitting or adapter to prevent any unnecessary
external force.
7.
Chemical Resistance – Consider the chemical resistance of the
tube, cover and the fitting, including the O-ring, to maximize hose
performance and life. Hose selection must assure compatibility of the
hose, tube, cover and fittings with the fluid used.
8.
The size of the hose assembly components must be adequate to keep
pressure losses to a minimum and avoid damage to the hose due to
heat generation or excessive turbulence.
9.
Extend hose assembly life by making sure hose and fittings are
compatible with the environment or sufficiently protected from the
elements, such as ultraviolet light, ozone, salt water or chemicals that
can cause degradation of assembly components and shorten hose life.
10.
A hose is designed with a certain level of abrasion resistance, but care
should be taken to avoid excessive abrasion, which can damage the
hose cover, accelerating hose failure.
11.
Use the proper end fittings and crimp or install to the proper crimp
specification to ensure a safe and proper hose assembly. Make sure
that hose fittings are compatible with the hose.
Appendix
Installation & Maintenance
Assemblies
Equipment & Accessories
Fittings
Hoses