The service life of products depends not only on product quality, but also on proper use and maintenance. Improper use may largely affect the quality and service life of products with fine quality, and may even cause severe accidents and property loss that should have been avoided.

 

The types, structures and working conditions of rubber hoses are rather complicated, therefore in order to ensure normal operation of the hydraulic system, please follow requirements given below:

 

I. Sealing tightness is a critical factor for hydraulic hoses and in actual application, water and air tightness must be ensured.

 

II. During the production process of hoses and hose assemblies, rubber scraps produced by cutting operation may affect the cleanness at internal walls of the hose. Please clean the hoses by using pressurized water and have air exhausted from the hoses as required, so that the hoses can work properly.

 

III. Rubber hoses may only be used for delivery of designated or recommended materials, otherwise the hose service life and safety will be compromised. Special media, such as drugs, acid, alkali, oil and paint, etc. may result in quick hardening, expansion or even failure of hoses, so use of rubber hoses above the upper limit should be avoided.

 

IV. In normal conditions, temperature of media delivered by rubber hoses should be between -40°C and +120°C.

 

V. Generally, rubber hose has strict requirements on temperature (temperature of media delivered and ambient temperature), therefore the temperatures, constant or instant, should in no case exceed the allowed temperature range. Hose sleeves are recommended for systems that operate in very high or low ambient temperature conditions. Thermal insulation layer should be used if ambient temperature is above 70°C.

 

VI. Hose assembly should not be used in conditions where the maximum allowed working pressure of such hose is exceeded (including surge pressure).

1. Working pressure of rubber hose is the maximum pressure measured in continuous operation, and in normal cases should not be lower than the maximum system pressure. In case the hose is not in frequent use, additional 20% working pressure is allowed, but if the hose is frequently used or bent, such working pressure should be reduced by 40%. If surge pressure produced by hydraulic system is higher than working pressure of the rubber hose, it may not only reduce hose service life, but also cause personal injury.

2.When the rubber hose is in use, the system pressure should be adjusted steadily and slowly, to avoid that excess surge and sudden increaseofpressuredamage the hose structure. Sudden pressure change or peak pressure value higher than maximum allowed pressure may significantly reduce hose service life.

 

VII. Rubber hose should not be used in twisted, stretched or squeezed conditions or when the bending radius is smaller than required value.

 

VIII. Please protect rubber hoses from contactingwith corrosive matters, such as acid (alkali), oil or other organic solvents and from contactingwith any hot surface.

 

IX. When in use, rubber hose should be protected from impact, squeezing, rolling by cars or heavy objects and abnormal vibration.

 

X. Neither international standards nor Chinese national standards make requirements on service life of rubber hoses, and users can determine a reasonable service life on basis of his actual situation and hose impulse performance. Hoses and hose assembly that have expired such service life or shelf life must be tested before they are used, to avoid extended use.

I-type wire-braid rubber hose should stand 150000 surge impacts without leakage or abnormal phenomena.

II-type wire-braid rubber hose should stand 200000 surge impacts without leakage or abnormal phenomena.

4SP and 4SH type spiral wire reinforced rubber hose should stand 400000 surge impacts without leakage or abnormal phenomena.

R12, R13 and R15 type rubber hose should stand 500000 surge impacts without leakage or abnormal phenomena.