Recent content by SurajS

Thank you for information!

I understand your concern, but in my case it is about emergency stop valve. So action of valve is very fast (20-30 millisec). Let me rephrase the question as: Charpy impact test data (notch (2mm * 45 degree) specimen with 10*10*55 mm size) shows energy absorbed= 45 Joules , and energy available...

If I have impact test data showing energy absorbed by notched specimen, how do I utilize this data while designing. In my case, i am trying to design the valve which closes by striking on valve seat, how do i use the impact test results for this design?

Yes , this is stop valve, so pressure difference has to be there across valve disc. I told null pressure difference just at the time of closure. I want to design for the worst case where to test the trip system, valve will be tested in absence of any steam. In presence of steam, impact will be...

Like you pointed out about the space, rather than bottom, I want to put the spring on top of stem. Stem diameter is about 16mm (0.63in). I want to know: will the valve force of impact be directly transferred to resetting lever through valve stem which needs to be absorbed by spring? Do i need...

Thanks for the suggestions. And yes boundary conditions are bit of a challenge but force is critical issue. One more thing, to absorb the valve shock, can we put disc spring on top of valve stem? Let me know about your view. Thank you for support.

Oh ok , understood. Can such high value of force be practical, because against this value valve stem has to designed for buckling. Whereas with F=dP/dt , value is much less.

Thank you sir, you are really helping me by all means. About the calculation you have provided, Just one glitch. with constant acceleration problem v= u+ at , a= acceleration, u= initial velocity, v= velocity at time t. You have considered 0.5*a*t. Nonetheless, force value is pretty much...

Hello sir, please let me know. Thank you.

Hello, I can understand the unit convenience. You can do the calculation in lb in system. I can convert comfortably. I am using SI units as here in India it is predominantly used. I was thinking can my valve be treated as ball falling from the height mentioned (Especially for impact time) I am...

Thanks for your help. I already estimated valve closure timing by writing differential equation of lever system which is second order DE. From that I had estimated time to close about 40 ms. This is not duration of collision. That is why i had assumed time of impact as 0.001 sec and yes mass...

Thanks a lot for detailed analysis. Here, please note, steam is present on above and below the valve disc in running condition. Valve needs to be closed against the effective unbalanced area (which is area of stem) on which steam force is acting in upward direction and spring closes against this...

Thanks for the insights. It is not a pressure relief valve. It is emergency valve of steam turbine which will required to be close the valve as soon as there is application of actuation force as shown in figure 1. And steam is trying to open the valve. So only force which is closing the valve is...

I am trying to design a cross section of valve stem and check its safety against buckling load. This is schematic representation of emergency trip linkage from US patent:US4379544.