Reliability Study Of Pneumatic Diaphragm Control Valve Based On Failure Mode Effect And Diagnostic Analysis

Regulating valve or control valve, as important equipment in petrochemical industry, is widely used in flow control in process control system. As power-operated flow control equipment, the reliability and availability of control valve, especially, pneumatic diaphragm control valve (PDCV), is critical to fluid machinery. The operation of valve is of critical importance for the long-term safe and efficient operation of process unit.In this paper, the reliability of PDCV was studied based on FMEDA method. The work contents and main achievements are listed as follows:(1)The characteristic of PDCV was analyzed based on failure modes effects and diagnostic analysis (FMEDA) in this paper. A risk matrix of PDCV was then put forwarded based on the FMEDA analysis, together with the reliability data of the control valve. The analysis method and reliability data obtained in this paper is benefit for SIL assessment of petrochemical installations.(2)A model was put forwarded in this paper for life prediction of a PDCV valve. Data supports the model was obtained from the field by failure investigation and statistics theory and probability figure method in Weibull 7 + + software were applied in the analysis.(3)Taking advantage of Monte Carlo sampling and life prediction model obtained in this paper, the time related failure characteristics of PDCV valve under break down maintenance and preventive maintenance conditions was also studied in this paper.Treating PDCV as a complex system and combining experience from the field, the reliability model which developed with theoretically analyzed is reasonable. At same time, the FMEDA method is introduced into reliability study of equipment for acquiring more data, and at same time standardizing the reliability research of valve.