3 replies to this topic

[Frederick34]

Hi everyone!

 

I'm process engineer in an oil refinery. A couple of months ago, we observed backflow in a caustic line due to the failure of a check valve.

 

The check valve was a ball type without spring (you can observe the diagram of this valve below)

 

I didn´t find any special requirements for check valves in caustic services (beside material or tracing requirements). So I suppose that ball types are suitable for caustic solution.

 

Is it possible have a failure (backflow) in an ball type check valve without spring as show in the table below?

 

Thanks!

 

 

 

 

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[Bobby Strain]

Seems like you provided the answer in your query.

 

Bobby

[breizh]

Hi,

I had similar issue with a water network  contaminated with caustic due to check valve failure . The objective was to dilute caustic with industrial water but because of the issue we changed  the process , adding a tank to prepare the mixture .

Difficult to rely on a check valve when there is a risk of contamination , sometimes people use 2 check valves .

 

Note : caustic soda is very viscous and tends to crystallize . It's not a good candidate for check valve.

Just my experience .

Breizh 

[fallah]

 

Is it possible have a failure (backflow) in an ball type check valve without spring as show in the table below?

 

 

Hi,

 

Yes, it's possible...the ball could be stuck at the top during normal flow then cannot prevent backflow in case of reverse flow...