Stopcock is a plug with a through hole as the opening and closing pieces, through the plug body and stem rotation to achieve the valve opening and closing action. Plug valve structure is simple, quick opening and closing, fluid resistance. This article made some improvements and calculations of the strength of plug valves used in drilling. Plug the opening and closing member is a perforated cylinder, around the axis of rotation perpendicular to the channel, so as to achieve the purpose of opening and closing channels. Plug valves are mainly used to open and close the pipeline and equipment media purposes. Plug the main advantages are: For regular operation, opening and closing fast, lightweight. Small fluid resistance. Simple structure, relative size, light weight, easy maintenance. Sealing performance is not limited by the installation direction, the flow of media can be arbitrary. No vibration, low noise. However, the plug valves used in drilling often appear after closing the problem is not easy to open, this paper conducted a series of discussions and improvements. Plug valve structure improvements: The lower part of the valve opening the way to make the pressure on both sides of the basic balance, the valve is very easy to open and close, to solve the problems of the original plug valve. Improve the plug valve strength is calculated as follows: 1 shell reference stress calculation A, ball valve hole center section 3-3a, tensile stress concentration analysis A, ball valve section 3-3 a, stretching 2 .. "Chemical Equipment Design Manual "Chapter 5 Pressure Vessel Design, the maximum stress of a cylindrical shell hole is found at the point where the tangential direction of the radial hole edge is parallel to the circumferential direction. The stress concentration factor is 2.5, that is, the stress concentration factor Take 2.5. Yield near the stress concentration point to occur. But less than 2, so stability. b, to reverse the stress analysis of the openings in the pressure vessel design of Chapter 5 of "Chemical Equipment Design Manual", it can be seen that the thin-walled cylindrical shell with the pinholes subjected to the torsion action has the maximum tensile stress appearing on the cross-section of the hole edge and the shaft On the hole by the role of the cylindrical shell of its stress concentration factor of 4. Will not yield. c, the internal pressure p = 105MPa role of the "stress concentration factor manual" found that the wall thickness of the cylinder wall with small holes to withstand internal pressure, available stress concentration factor A = 3.03 to yield in the stress concentration point, but stable. B, snap ring section 2-2 at a, stretching from the "Stress Concentration" book found in the nomogram A = 2. 8 in the stress concentration point (at the intersection of the fillet and the inner wall) yield to occur. But stable. b, reversed by the "stress concentration" book Nimu plans to find A = 1. 8 will not yield. c, the internal pressure p = 105M Pa role According to "chemical container", the wall thickness of the cylinder at the junction of the local stress calculation method, the maximum stress in the thin wall (for the longitudinal stress) C, cone valve hole section 4-4 a , Stretching by the "Chemical Equipment Design Manual" Chapter 5 pressure vessel design, found that the maximum stress of cylindrical shell openings occurred in the radial cross-section, the stress concentration factor A = 2.5 stress concentration alone when stretched The coefficient is taken as 2.5. Yield near the stress concentration point to occur. However, Andingfang b, reversing the stress analysis near the openings in the pressure vessel design in Chapter 5 of "Chemical Equipment Design Manual" shows that the stress concentration of the thin-walled cylindrical shell with small holes and the maximum tensile stress At a 45 ° cross-section to the shaft, the stress-concentration factor of the cylindrical shell with small holes is taken to be four. Will not yield. Section 1 - 1 a, Stretching The design of the pressure vessel in Chapter 5 of the Chemical Equipment Design Manual, the maximum stress of the cylindrical shell hole is found at the point where the tangential direction of the radial hole edge is parallel to the circumferential direction. The stress concentration The coefficient A = 2.5, that is, the stress concentration factor when stretched alone is 2.5. Yield near the stress concentration point to occur. stable. b, to reverse the stress analysis of the openings in the pressure vessel design of Chapter 5 of "Chemical Equipment Design Manual", it can be seen that the thin-walled cylindrical shell with the pinholes subjected to the torsion action has the maximum tensile stress appearing on the cross-section of the hole edge and the shaft On the hole by the role of the cylindrical shell of its stress concentration factor of 4. Will not yield. 3,1 internal pressure 105MPa role from the "stress concentration factor manual" to find the cylinder wall open small holes with thick-walled cylinder withstand internal pressure, available stress concentration factor A = 3. 03 4 conclusion will not yield. From the above stress analysis, the following conclusions can be drawn: 4.1 Under the three given loads, the stress under the tensile load is the highest with the least safety factor. Therefore, the tensile strength under stress conditions is the main contradiction. 4.2 Stretch to the common plug valve material 40CrMnMo calculation, the safety factor of 1.71> 1.5, to meet the strength requirements. 4.3 Tensile load at the knob orifice at a large concentration of stress in the stress concentration point have reached the yield limit of the material, in accordance with the new strength criteria, the maximum stress concentration point 935.75MPa 4.4 Tension in the groove The benchmark stress and stress are also large, but can meet the strength requirements. In the design should pay attention to reduce the stress concentration here. 4.5 Given the torsional and internal pressure loads, the safety factor for each of the critical cross sections is large, regardless of their strength.
Vinyl Pool Light,Underwater Led Pool Light,Vinyl Liner Pool Light,Resin Filled Vinyl Led Light
Guangzhou Qshine Pool Lights Manufacture Co., Ltd , https://www.gdqshinepoollight.com