Design method for back pressure-bearing flat cover

Abstract

The invention discloses a design method for a back pressure-bearing flat cover, belongs to the technical field of flat cover strength design of a pressure container, and aims to solve the problem of astrength check and design method for an existing structure adopting the back pressure seal flat cover. The method comprises the steps of 1: calculating a center circle diameter Dg of a gasket under the action of a tight pressing force; 2: calculating a total thickness B value of the flat cover; 3: calculating out a total action force W of the back surface of the flat cover under an action generated by a calculated pressure Pc, and according to a force balance condition, enabling a numerical value of the total action force to be equal to a force F acting on the seal gasket; and 4: checking thestrength of the most dangerous work section of the flat cover. Through the design method for the back pressure-bearing flat cover, the problem of low stability of the tight pressing force of the backpressure flat cover due to existing design of the structure adopting the back pressure flat cover can be solved, so that the mounting and repair cycle of the back pressure flat cover of the pressurecontainer is effectively controlled and the repair cost is reduced.

Description

technical field [0001] The invention relates to a method for designing the strength of a back pressure-bearing flat cover, belonging to the technical field of strength design for a flat cover of a pressure vessel. Background technique [0002] Flat caps subjected to back pressure, the structure of which is shown in figure 1 , the gasket and the pressure-bearing surface are on different surfaces of the flat cover, also known as self-tightening flat cover. The pressure-bearing characteristic is that when the pressure increases, if there is no limit mechanism at the gasket structure, the gasket compression force will increase with increasing pressure. This situation is more in line with the principle of sealing, so it is called a self-tightening flat cover. [0003] Positive pressure flat cover such as figure 2 , the gasket and the pressure-bearing surface are on the same side of the flat cover, and the gasket compression force is realized by the bolt tightening force. The ...

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Problems solved by technology

[0004] The back pressure flat cover has the advantages of compact structure, and the same condition requires less metal than the positive pressure flat cover, that is, the economy is better; in addition, it is easier to achieve sealing, but the disadvantage is that the maintenance is not as convenient as the positive pressure flat cover. Because the back pressure flat cover is installed inside the equipment, the operator must enter the inside of the equipment to observe the positive pressure flat cover, and then carry out maintenance work

[0005] At present, there is no rule design method given in the pressure vessel design standard specification (GB150) for the strength check and design of flat cover components subject to back pressure, and there is no similar case support. Therefore, when carrying out this type of structure, the designer adopts The calibration methods are different, and the use of these different design methods will easily lead to insufficient structural strength of the back pressure flat cover, which will lead to the pressure vessel designed with the back pressure flat cover unable to guarantee the sealing reliability. Therefore, it is urgent to propose a standardized pressure vessel The strength design and checking method of the back pressure-bearing flat cover to ensure the safety and sealing reliability of such pressure-bearing components

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