Oriface Flowmeters relation to Pipe Class. 2

[Ulon]

Hi guys,

Flowmetering is new to me. I come acroos my company standard document, and it stated that for an oriface plate, is shall be ANSI 300 as minimum.

According to that, if the pipeline is using ANSI 150 pounds, but the oriface plate still need to be ANSI 300. Any technical reason for that?

all that i'm aware is that the bore will be according to the pipe diameter.

Really appriciate your help.

Thanks guys,

 

[JLSeagull]

Flange taps are drilled in orifice flanges. Thus the flanges require thicker material than exists in Class 150 flanges. See B16.36 for orifice flanges. For more details, also consider the thickness of orifice plate and gaskets along with the flow measurement standards, etc.

 

[roydm]

Once the line size gets up to about 10" you can use "Pipe Taps" with 150# flanges/
Less than that the Pipe Taps would be too close to the flanges.
Roy

 

[Joesteam]

I am not sure that the ID/OD for a wafer style 300# plate will fit the 150# flanges....

Joe Lambert

http://www.control-associates.com/

 

[roydm]

Joesteam,
No it won't, you need to specify the correct connection.
Good catch.
Roy

 

[JLSeagull]

The outside diameter of the orifice plate fits inside the flange bolt holes. See ASME B16.5 for flange bolt holes. ASME MFC 3M, API MPMS 14.3.2 and ISO 5167 part 2 reflect the inside dimensions for paddle type orifices.

API MPMS 14.3.1 reflects the flange taps as a pair of tap holes positioned with the upstream tap center located 1 inch (25.4 millimeters) upstream of the nearest plate face and the downstream tap center located 1 inch (25.4 millimeters) downstream of the nearest plate face.