7 replies to this topic

[shahidulislam48]

Hi,

 

I had been working with control valve data sheet. It had been provided by me to manufacturer but there was no mention of flow characteristics in the data sheet. When the manufacturer had provided us the data sheet according to their products specifications I had found that there was "Equal Percentage" as flow characteristics.

 

Is there any criteria or procedure so that we can verify the flow characteristics that is provided by the manufacturer is appropriate according to our process?

 

Thanks in advance.

 

Shahidul Islam

[latexman]

Valve manufacturers always provide the wide open Cv or Kv, and usually provide a table with 5-10 data points of valve % open vs. Cv or Kv.

[shahidulislam48]

Valve manufacturers always provide the wide open Cv or Kv, and usually provide a table with 5-10 data points of valve % open vs. Cv or Kv.

But how could I justify their recommended flow characteristic is suitable for my process?

[ankur2061]

Hi,

 

Download the excel spreadsheet from my post (#5) in the attached link to know description and application of linear and equal percentage control valves:

 

https://www.cheresou...gas-and-liquid/

 

Also refer these other links to understand about linear and equal percentage control valves:

 

https://www.cheresou...haracteristics/

 

https://www.cheresou...considerations/

 

Regards,

Ankur.

[shahidulislam48]

Thank you Sir.

[breizh]

Hi ,

Some training materials you may found of interest to support your work .

 

Hope this is helping you .

Good luck

Breizh

[fallah]

 

Is there any criteria or procedure so that we can verify the flow characteristics that is provided by the manufacturer is appropriate according to our process?

 

 

Shahidul Islam,

 

Hereunder you can find some guidelines to make decision which type of flow characteristics is appropriate for the specified process conditions:

 

*Equal Percentage:

 

Is normally applied for temperature and pressure control loops and where minor portion of the control system's pressure drop is through the control valve

 

*Linear

 

Is normally applied for level and flow control services and where the major portion of the control system's pressure drop is through the control valve along with required fairly constant pressure drop across the valve

 

*Quick Opening

 

Is normally applied for frequent on/off services e.g. for batch processes or where an instantly large flow is required such as deluge systems
 

[shahidulislam48]

Thanks Sir fallah and breizh for your support.