The labyrinth compressor elastic coupling bolt fracture analysis of the causes

The labyrinth compressor 2020 - elastic coupling bolt fracture reason analysis 06 - 19 shi-yong zhang cyl ma jin 1 Shen Deying lee smile rock 3 (2 1. Shenyang yuanda compressor co. , LTD. ; 2. Brilliance BMW automobile co. , LTD. 3. Shenyang blower group co. , LTD. ) Abstract: in order to eliminate the safety hidden trouble, improve the safety, reliability and economy of compressor equipment, in view of the two large labyrinth compressor coupling bolt fracture reason carried on the thorough careful analysis, find the cause of the accident, and the coupling cell communication, optimize the structure of coupling, replaced after coupling used in good condition at the scene, to ensure the compressor at the request of the long running under the rated conditions. Key words: labyrinth compressor; Elastic coupling; Bolt fracture 1 2 sets of large labyrinth compressor, introduction company put into operation in January, under the rated conditions run less than A week, A, B2 units successively appeared elastic coupling bolt fracture mechanical accidents, and accident phenomena are basically identical. The coupling domestic manufacturers to improve the coupling structure of form A complete set, the compressor running under the rated conditions only three days, A and B unit appeared fracture mechanical accident of coupling bolts, the serious influence the user's normal production schedule, causing great economic losses. In order to avoid the similar accidents from happening again, improve the safety, reliability and economy of compressor equipment, the company dedicated to the two labyrinth compressor matching elastic coupling bolt fracture reason is analyzed. 2 the scene of the accident bolt fracture in the form a complete set of mechanical accident coupling structure as shown in figure 1. 2 times A and B machine coupling bolt fracture, the coupling damage as shown in figure 2. 3 coupling bolt stress analysis of bolt number Z = 10, play a role for 10/2 = 5, bolt circle ф 495 mm diameter, bolt do ф = 40 mm diameter, bolt material of 35 crmo, quenched and tempered treatment, for the theory of bolt is trying to figure 3. According to the material characteristic of bolt, the mechanical properties of the bolt is as follows: according to the coupling of the compressor normal work the actual working situation, using professional software, finite element stress analysis was carried out on the coupling bolts, the results of the analysis as shown in figure 4. From figure 4, you can see that the maximum stress of the bolt also occurred in the diaphragm shear, but the maximum shear stress for 139. 39 mpa, higher than the theoretical value, this is because in finite element analysis, considering the coupling of the actual situation of work defines the connection relations between various components, given the friction coefficient and so on, more accord with the actual stress condition, coupling analysis value is greater than the theoretical value, so the result is in conformity with the theoretical analysis. Comprehensive the above results can be seen, the safety factor of coupling working time only to 1. Five or so, low safety factor. 4 the cause of the accident analysis based on the above calculation, the safety factor of coupling bolts is too low, is one reason for the bolt fracture. Through the analysis of coupling damage further carefully on the spot, this paper analyzes the reason of the bolt fracture is as follows: ( 1) Coupling bolt and the flange and bolt hole on diaphragm fit clearance is too large, and size is not uniform, as shown in figure 5, after the load nodes generate large displacement, resulting in instability buckling deformation of diaphragm, diaphragm in the process of transmission torque does not work properly. （ 2) Diaphragm positioning holes are obviously not complete set of finishing machining marks, roughness of 25 or more, as shown in figure 6. Rough set of hole, the positioning of the coupling bolt occlusal surface damage, induce bolt multi-source fatigue fracture, and bolt positioning surface anticorrosion measures. Coupling manufacturer with new bolt positioning surface has been able to clearly see the rust, as shown in figure 7. （ 3) Coupling in the middle of the section 5 of the bolt holes and positioning fit surface has obvious to the rotation of the circumference of a circle all around bite marks, suggests that positioning clamping set loose, when the normal work of the coupling, locating sleeve have obviously the phenomenon of rotation, fastening torque is not enough, as shown in figure 8. （ 4) Bolt locking of the gasket is shedding spring washers, this design is not in conformity with the API671 8. 10. Article 3 the provisions. 5 conclusion has two large labyrinth compressor due to the coupling bolt fracture, which units cannot be run in for a long period of time, affect the normal production and cause economic losses. After detailed analysis, safety coefficient is low, parts processing poor quality and unreasonable structure is the main cause of the coupling bolt fracture. Through close communication and coupling manufacturer, replaced after structure optimization, the coupling at the scene used in good condition, ensure the compressor at the request of the long running under the rated conditions. Source: the compressor technology 01, 2016