BS EN 14359:2017 pdf download.Gas-loaded accumulators for fluid power applications.
BS EN 14359specifies the requirements for materials, design, manufacture, testing inspection, safety equipment configuration and documentation (including instructions for first operation), for commonly-used types of gas-loaded accumulators and pressure vessels used to provide additional gas capacity for fluid power applications (see 1.2).
1.2 This European Standard applies to the following types of components, defined as the pressure-
containing envelope of gas-loaded accumulators:
— bladder type;
— diaphragm type;
— piston type;
— transfer type;
— pressure vessels used to provide additional gas capacity.
They consist of one or several parts joined together by a variety of mechanical means and by welding.
1.3 This European Standard applies to gas-loaded accumulators which operate with the
following conditions:
— subject to an internal gauge pressure greater than 0,5 bar;
— working temperature not lower than —50 °C and not higher than +200 °C;
— containing all liquids and gases as defined in the Pressure Equipment Directive 2014/68/EU, see Note.
NOTE When the accumulator contains Group 1 liquids or gases, consideration relating to risks other than those required by Pressure Equipment Directive 2014/68/EU are not covered by this European Standard and will be assessed separately.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
3 Terms, definitions, symbols and units
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1 gas-loaded accumulator
hydraulic accumulator with separator between liquid and gas where the liquid is pressurized using the compressibility of an inert gas (for example nitrogen)
Note ito entry: The separator can be a bladder, a diaphragm or a piston.
Note 2 to entry: Gas-loaded accumulators have shells, which can consist of cylinders, dished ends and flat plates. Openings are always isolated, located on the axis centre line and positioned at both ends of the accumulator. It is assumed that such vessels are axis-symmetrical.
3.1.2 bladder accumulator
gas-loaded accumulator consisting of pressure-retaining shell, either spun-forged from seamless tube, hammer-forged from hollow bar or of welded construction, in which the liquid and gas are separated by a flexible bag or bladder normally retained at one end of the shell
3.1.3 diaphragm accumulator
gas-loaded accumulator consisting of pressure-retaining shell assembly, in which the construction can either be screwed or welded, with integral ports in which the liquid and gas are separated by a flexible membrane normally retained at its largest diameter to the shell
3.1.4 piston accumulator
gas-loaded accumulator consisting of cylinder body and end cap assemblies in which the liquid and gas are separated by a rigid sliding piston
3.1.5 transfer type accumulator
gas-loaded accumulator with a port for connecting additional gas capacity from one or more pressure vessels (e.g. gas bottle)
4 Materials
4.1 Requirements for metallic materials
The pressure containing envelope of gas-loaded accumulators shall be constructed of either:
— harmonized materials used for the manufacture of unfired pressure vessels and meeting the requirements of EN 13445-2;
— materials other than those specified in EN 13445-2 provided that they have been accepted by a particular niaterial appraisal;
— materials covered by European approval for materials in accordance with Article 15 of Pressure Equipment Directive 2014/68/EU.
4.2 Material certificates for components of the pressure containing envelope
Components used in the manufacture of the pressure containing envelope of gas-loaded accumulators to category II, Ill and IV according to Annex II of the Pressure Equipment Directive 2014/68/EU shall be accompanied by an inspection document in accordance with EN 10204 type ii (see Annex Ill of the Pressure Equipment Directive 2014/68/EU). Such components shall include, but not be limited to, those determined by the application of the calculation formulae within this standard.
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
Where there is a risk of corrosion, a protection method and/or corrosion allowance shall be applied to the affected surfaces of the accumulator.
Consideration must be given to the potential for corrosion due, both to the internal fluid and external environment. This should be countered by methods including, but not limited to, choice of corrosion- resistant materials or the use of linings or coatings.
Only completely impervious, sufficiently thick and chemically stable layers with an average life, not less than that of the pressure vessel, shall be considered to be reliable protection against corrosion. When in doubt, corrosion tests shall be undertaken.
If there is no contact between the corrosive agent and the vessel base material, then it is not necessary to provide a corrosion allowance for wastage of the base material.
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.BS EN 14359 pdf free download.