27 replies to this topic

[fallah]

dear fallah,
Thank U so much. This is a big help for a fresh engineer like me.
Another question: in the all normal cases, I can calculate and seek out the corresponding Cv of control valve. The vendor of control valve can confirm its final size according to these Cv. For case of control valve failure, when calculate relieving flow of PSV, we should use the Cv of fully open control valve. But some time, this value is too great and accordingly, the relieving flow is too great. For this problem, I find some one use the double Cv of the normal case as the the Cv of fully open control valve to calculate the relieving rate. Is this method right? whether this method is related to the selective principle of the Cv value?
Jia Tong

Jia Tong,

Do you certain using double Cv of the normal case of control valve instead the Cv of fully open would result in a lower releiving rate?

Anyway, IMO this isn't a logical method and i don't recommend to use.

Fallah

Edited by fallah, 22 November 2011 - 03:51 AM.

[Yogesh Bhatt]

Dear Venktesh,

There is a standard chart in EIL engineering guidlines with respect to control valve, block valve & bypass valve size is defined. This is thumb rule no need to go for any calculation.

Generally for the lower size of control valve around 3 " bypass valve size shall be same as control valve size & above that one size lower. Please follow standard table.

Regards,

Jatin

Hi Jatin

 

Can you provide the EIL guidelines for my reference.

 

Thanks

[jrtailor09]

Dear Venktesh,

There is a standard chart in EIL engineering guidlines with respect to control valve, block valve & bypass valve size is defined. This is thumb rule no need to go for any calculation.

Generally for the lower size of control valve around 3 " bypass valve size shall be same as control valve size & above that one size lower. Please follow standard table.

Regards,

Jatin

Hi Jatin

 

Can you provide the EIL guidelines for my reference.

 

Thanks

 

 

Dear Yogesh,

 

It is basically prepared from API 550 only.

Please ind attached file for your reference.

Regards,

 

Jatin Tailor

Attached Files

•  CV.pdf   21.94KB   135 downloads