BS EN 14359:2006 pdf download – Gas-loaded accumulators for fluid power applications
5 Basic design and calculation criteria 5.1 General The requirements of Clause 5 shall apply when the materials and welds are not subject to localised corrosion in the presence of either products which the gas-loaded accumulator is to contain, or the environment in which it is located.
5.2 Corrosion A corrosion allowance is not normally required for accumulators covered by this European Standard. Where there is a risk of corrosion, a protection method and/or corrosion allowance shall be applied to the affected surfaces of the accumulator.
5.3 Qualification by similarity Accumulators are often serially produced and it is possible to qualify a range of accumulators based upon the design, calculation and testing of one model within the range provided that other accumulators are similar. Two accumulators are similar provided that:
they are made of the same material of the same form and origin;
they are identical with the exception of length;
the internal length of the cylindrical portion is not less than three times its external diameter. If the length of the cylindrical portion is less than three times its external diameter, then a detailed stress analysis shall be undertaken.
5.4 Design methods
5.4.1 General This European Standard specifies methods for the design by equations of accumulators or accumulator components. Satisfactory application of such equations alone shall be sufficient to demonstrate conformity to this European Standard provided the accumulator will be subjected to less than 500 pressure cycles between P 2 and P 1 during its lifetime. Where the accumulator will be subjected to more than 500 pressure cycles between P 2 and P 1 , the manufacturer shall make an assessment for the effects of fatigue, either by analysis or test. This assessment shall form part of the Technical Documentation File. Clauses 17 and 18 of EN 13445-3:2002 shall be used as the basis for a fatigue analysis and 7.6 of this European Standard shall be used as the method for conducting a fatigue cycling test. Figure 5.1 shows the design process to be adopted.
5.5 Design and calculation methods common to all accumulator types
5.5.1 General
All applicable equations shall be used in order to demonstrate conformity with this European Standard.
The maximum allowable pressure PS can be replaced by the test pressure PT when calculating for test conditions.
5.5.2 Specific definitions
right circular cylinder
Torispherical end
dished end, made up of a spherical cap, a toroidal knuckle and a cylindrical shell, the three components having common tangents where they meet
torispherical end for which R/D e = 1,0 and r/D e = 0,1
torispherical end for which R/D e = 0,8 and r/D e = 0,154