6 replies to this topic

[Indu]

I am tryign to find teh K value for in line filters for nitrogen supply line.
My vendor could only provide me with a DP, which I thought would be pretty simple if I can convert to K.
The max Dp is 80psi across this filter, so I took that , got the head from Dp(144)/rho
and then calculated the K from K = 2gh/v2 where my v is 134 ft/s.
I get a K of a whopping 175...


Is this an acceptable K value?
This makes my pressure drop really high.

[latexman]

The clean condition K I use for a Y-type strainer is K = 2, and the dirty condition K I use is 10x that. A reasonable dP for a Y-type strainer is 0.1 to 10 psi, that's what most vendors provide data on.

[Indu]

This is a Capsule filter (probably about 10" in heigt) and approximately 2" in diameter.
the Dp on this is like 80 psi.
I am not sure about the strainer though.

[latexman]

The vendor can give you the max. dP the filter can take, but you must figure out and decide what the max. dP the process/system can take. For example, if the dP builts up to this 80 psi, will your process/system still funtion properly?

[Padmakar Katre]

Dear,
Addition to the posts I have seen the Oxygen line filters in EO/EG plant which are designed for max Delta P of 10 kg/cm2g e reason is to avoid a probable fire in the filter in case of sudden stoppage of the Oxygen the filetr element would experience this much of delta P (max). This is just posted as I saw very less pressure drops in the earlier posts so I just wanted to mention about the delta pressure design of the filter or filter element can be 10 Kg/cm2g.

Regards,
Padmakar Katre

[JEBradley]

Well this post follows on from me stating that the K value is surprisingly low for filter.....
MISTAKE

Actually, the pressure drop was low...which isnt the same thing.

I did a calculation using your data and a few extra assumptions and I got a K value of 138 so pretty much the same as you (although I think I used a different method).

Ill post the s/sheet tomorrow as it's on my other computer.

A strainer will have a lower K value than a filter (he said confidently lol - I prepare to be shot down)

[JEBradley]

And here's the calc I used...

Attached Files

•  Filter_K_Values.xls   40.5KB   161 downloads