2 replies to this topic

[siddiquiee]

Dears,

I would like to know, for sizing of level control valve we assume min and max flow and inlet pressure and pressure drop but my concern is how in level control valve operates in min/max flow. only level transmitter manipulates the control valve through 4-20mA.

We are considering ie 500 BPD 10% opening of valve and 5000 BPD 85% of level control valve but we are controlling through the level transmitter, how control valve opening and closing based on flow rate.

Please advise me I am totally confuse.

[S.AHMAD]

1. The level is controlled by regulating flowrate. For example, liquid level in a process vessel is controlled by regulating the liquid flowrate at the bottom of the vessel.
2. If the level higher than the set-point, the control valve will open more so that flowrate will increase and the level will drop accordingly to the set-point.
3. Similarly, when the liquid level drop, the valve opening will be reduced such that flowrate will also be reduced and r esult in liquid accumulation in the vessel
4. We need to know the min/max flowrate this is to ensure that the control valve selected operates within the right ranges and the valve opening at normal flowrate should be around 70~80 %.
5. What would happen if, let say the incoming liquid is 10,000 kh/h but the control valve is sized for maximum rate of 9,000 kg/h?