Flexibility and minimum bending radius are important factors in the production and choice of hoses, especially if the hose is subject to considerable flexing during its use.
It is important to make sure that the minor bending radius planned for the use of the hose is more ample than its minimum bending radius. If the bending radius reached during its use is smaller than its minimum bending radius, the hose can be smashed, its diametrical section deformed or narrowed, or even crush and close. Or it can be excessively stressed to damage the fabric layers and therefore reduce its resistance and/or its life, or even to cause its breaking.
The minimum bending radius is normally indicated for every hose. During its use the hose can be flexed to this radius without damage or excessive reduction of its life. Each manufacturer defines his own bending radius. Some of them take as reference the medium diameter of the hose, while others the external wall. Take it into account in case of comparisons.
Formula to determine the minimum length of a section of hose that indicates the bending radius and the necessary bending radius for the use:
There are: α = bending angle r = hose bending radius φ = hose external diameter L = hose minimum length
For example: For a 90° bending of a hose with an outer diameter of 90 mm, the hose minimum length with a bending radius of 400 mm, is calculated as follows:
In this case the bending must extend along the hose length for at least 700 mm.