| Quick-opening door pressure vessels are widely used as an important production equipments in building industries, materials, chemicals textile, pharmaceutical and health. According to statistics, quick-opening door pressure vessel explosion accidents accounted for about one-third of the total proportion of the pressure vessel accidents in China. The safe operations of the pressure vessels are related to the life and property safety of the people. As a typical kind of quick-opening door pressure vessels, researching on the safety interlock of autoclaves have an important application value. In this paper, safety interlock device failure analysis and improvement measures of the autoclave are carried out. The studies and research mainly includes in the following aspects:(1) The four typical cases of safety interlock failures in the quick-opening door pressure vessels-autoclaves are analyzed, improper interlocking mechanism design and management are mainly responsible for the failures, such as the presence of unauthorized alteration chain, engagement is not in right place, etc.(2) The stress analysis and strength calculations in the safety interlock structure of autoclaves are carried out. The tank cover flange-section whose calculated stress is closest to the allowable stress in the design criteria. This section is most stress concentrated sectional portion (the most prone to failure part). The minimum limit length of engagement about the cylinder flange with tank cover flange was studied. If the safety interlock structure engaging surface can not reach the minimum, and can lead to the safety interlock device failures.(3) The current national standard has not been established for the performance of safety interlock device based on the analysis of the failure basis of safety interlock device and the current autoclave technical conditions, the relevant standards of safety interlock device are discussed considering the scope and requirements of injury risk factors. Direction and specific method of interlock device standards are proposed from the design, manufacture, installation, maintenance, renovation and other activities segments.(4) Based on theoretical and practical analysis, the improved measures of safety interlocks device are proposed. The measure to improve the position switch was put forward and researched by the author, eddy current proximity switches is used to replace the original limit switches, which can effectively prevent from failures in the safety interlock devices due to poor working conditions, other improved measures in the enterprises have also been put forward, such as the using of modular safety interlocks, increasing tooth interlock device, increasing the power-off delay device, using function testing equipments of safety interlock in the quick-opening door vessels, strengthening the safety interlock device management, and improved detection methods, etc. |
