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4

# Split Range Control

4 replies to this topic
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### #1 sdibyendu

sdibyendu

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Posted 03 February 2019 - 08:32 AM

I'm currently working on a project when in one control application two sets of control valve in parallel has been provided to cater wide range of flow. Can anyone suggest any thumb rule to decide on % split of controller output among those two valve. For reference smaller size valve is designed to cater a flow 0.025 ~ 0.13 mmscmd gas flow whereas bigger one is to manage 0.13 ~ 0.55 mmscmd

### #2 breizh

breizh

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Posted 03 February 2019 - 09:54 PM

Hi ,

you may find pointers using the link attached .

https://www.instrume...control-in.html

hope this is helping you.

Breizh

### #3 latexman

latexman

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Posted 04 February 2019 - 07:32 AM

Traditionally, the 4-20 mA output controller is split 4-12 mA (0-100% open) and 12-20 mA (0-100% open).

On flow rates may I suggest:

0.55/0.025 = 22

(22)1/2 = 4.7

0.025 * 4.7 = 0.12

0.55 / 4.7 = 0.12

So, 0.025-0.12 and 0.12-0.55

### #4 Bodhisatya

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Posted 26 April 2019 - 10:30 AM

nivedita12:

Please create a thread of your own, don't hijack other's post.  Surely our esteemed members will assist you once you post your query in an accurate manner.

Bodhisatya.

### #5 Bodhisatya

Bodhisatya

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Posted 26 April 2019 - 10:40 AM

I'm currently working on a project when in one control application two sets of control valve in parallel has been provided to cater wide range of flow. Can anyone suggest any thumb rule to decide on % split of controller output among those two valve. For reference smaller size valve is designed to cater a flow 0.025 ~ 0.13 mmscmd gas flow whereas bigger one is to manage 0.13 ~ 0.55 mmscmd

Hello

Size the smaller valve for turn down flow rate (Typically for 50 or 60 % of rated capacity),i.e the small valve to cater the turn-down case flow rate.It is normally tightly sized ,i.e Calculated Cv and selected Cv are comparable.This valve operates withing the 0-50 % FIC output window.

Size the bigger valve for Normal/Design Case and Max Case ,will operate within the FIC output window of 51-100 %.The current split (4-20 mA) should be as pointed out by Latexman.

Regards

Bodhisatya.