Pressure vessels are used in many industrial fields, for instance refineries, chemical, petro-chemical, biotechnological and cryogenic industries. The safety of vessel exploitation demands qualification tests which are, at present, hydraulic tests. Every pressure vessel has to undergo these qualification tests both at the final acceptance stage before its first usage and on a periodic basis during its life span. The advantage of the regulatory hydraulic proof test is that it verifies whether the pressure vessel is capable of withstanding the maximum service pressure. However it is costly and still gives little information about the integrity of the structure. In particular, it cannot detect the presence of evolving defects. In certain cases there is a risk, firstly of causing defects which will evolve without being detected and, secondly, of affecting the performance of the vessel with ice formation and corrosion as a result of the moisture that remains. Pneumatic tests of vessels is a way to overcome these difficulties, but could be widely used and specified in regulations only when the safety of such tests can be guarantied. The aim of the project is to develop and validate a real time surveillance method to ensure the safety of pneumatic tests on pressure vessels, using Acoustic Emission measurements (A.E.). This surveillance method will enable a decision to be made as to whether vessel pressurization should continue or be stopped when changes affecting a defect of a dangerous nature are detected and located. The real time decision of the detection of an evolving defect and the eventual stopping of the vessel pressurization will be supported by a system based on a neural network. The method will answer to industrial specifications for pressurisation tests (security requirements, cost requirements, admissibility with certification organizations and insurance companies, link with standardization). it will cover the settlement of a European database prototype, the development of a validated monitoring system and the definition of a test procedure which will be developed and validated in situ conditions.
Funding SchemeCRS - Cooperative research contracts
3730 Vale De Cambra
4465-591 Sao Mamede De Infesta