3 replies to this topic

[ikyikhram]

Hello Guyz,

 

i have a question here , 

                                        1) what is Opening time for ESDV

                                        2) what is Closing time for ESDV ( - one second for each inch of valve size  considered as a  valve closing time. <-- correct me if im wrong )

                                        3) is there any standard for both (opening & closing time) 

 

thank you,

ikyikhram

Edited by ikyikhram, 22 July 2013 - 03:49 AM.

[fallah]

Hi,

 

My answers as red highlighted in below:

 

 

 

i have a question here , 

                                        1) what is Opening time for ESDV

 

Not so important as closing time,it could be higher than closing time such that actuator size wouldn't be so large...

                                        2) what is Closing time for ESDV ( - one second for each inch of valve size  considered as a  valve closing time. <-- correct me if im wrong )

Yes,one second per one inch of valve nominal bore size is a good engineeing practice

                                        3) is there any standard for both (opening & closing time) 

As far as i know, there is no special standard and it should be specified based on process and piping conditions. For example in one practice is mentioned that in order to avoid the surge effects the time in seconds to close a valve must be greater than twice the length of the upstream pipe. Also for more rigid pipe the closing time should be slower due to lack of adequate pipe elasticity...

 

 

Hope it helps you out...

[ikyikhram]

Mr Fallah,

 

thank you so much for your response , yeah it helps me a lot,

 

FYI, my ESDV is 6" ..the problem is my customer want the closing time is less than 6 seconds, make sense (mine is 3sec) , but they want the Opening to be 12 sec (mine is 27 sec) now im trying to put the Booster ... let see what is the result

[fallah]

Hi,

 

As i mentioned, it depends on the process and piping conditions, and at a glance appears the opening time (12 sec) for such 6" valve will lead to no major problem but about the wanted closing time equal to 6 sec it might lead to non standard pneumatic accessories and high volume of air along with the possibility of surge risk due to the fast closing of the valve...