Reliability Analysis Of Pneumatic Diaphragm Control Valve Based On Ahp/Hor Model

As important equipment in petrochemical industry, control valve is widely used in process control industries. Also as power-operated flow control equipment in fluid machinery, the control valve, especially, pneumatic diaphragm control valve (PDCV), as the most common control valve, is critical to petrochemical industry. The reliability and availability of PDCV is of critical importance for the long-term safe and efficient operation of control loops.Failure mode effects and criticality analysis (FMECA) is a well known assessment tool used to identify the components most likely to cause failures and to enhance system reliability. Unfortunately, it has been largely questioned for a few limits. The paper proposes a completely new approach, robust, structured and useful in practice, for reliability analysis. Than dealing with the criticality analysis of PDCV is presented. Moreover, using and corresponding stochastic Petri net (SPN) models for PDCV are constructed. That provides a new approach in terms of the reliability research of PDCV, which possess certain practical engineering value. The work contents and main achievements are listed as follows:1. This paper presents an advanced version of the FMECA, named AHP/HoR model, whose capabilities are enhanced; in that the criticality assessment takes into account possible interactions among the principal failure modes. This is obtained by integrating FMECA, Analytic Hierarchy Process (AHP) and House of Reliability (HoR). The methodology, within an integrated approach, overcomes some of the largely known limits of standard FMECA: it takes into account multiple criteria, differently weighted, it analyses the product considering not only the direct consequence of a failure, but also the reaction chain originated by a starting failure.2. For the high reliability demand of the PDCV, use AHP/HoR to analyze the potential failure modes and get critical rankings. The application of the proposed approach allows users to identify and control the design and manufacture requisites affecting reliability and finally enhances the reliability. 3. The building and analysis procedure of SPN model for the reliability of a system is proposed in detail. Considering the building and analysis procedure of SPN model, corresponding SPN models for PDCV and its work process are constructed, and several important reliability metrics are derived.