orifice plate..help me

If the flanges between which this orifice plate is to be installed are RF, the flat orifice plate is fine. You can check the bolt circle and bolt diameter dimensions to make sure the 8.60 o.d. plate fits within the bolts (I'm pretty sure it will). If there is lots of clearance, measure the plate when you install it so that it is centered within the bolt circle, and align the flanges carefully. It looks like you're okay.

Tapered inlet is not required? as received inlet is circular.

I checked by installing it between flanges it is ok , i think so. After fixing the bolts it will be fine.

tell me onething Flange is 8" 150 pound then why outer diameter is 280mm is there any calculation for that

Ideally, the outer diameter of the orifice plate should be at least as large as the o.d. of the raised faces (RF) of the mating flanges, but less than (bolt circle minus bolt diameter) of these flanges. This is not really a calculation, but rather a matter of looking up the values in a dimensional table. I will try to check further.

The orifice flanges are specified and procured in accordance with ASME B16.36, and per ASME code there is no orifice flanges with Class 150, where the 1^st class is 300 as indicated in Table 1 Class 300 Orifice Flanges, Welding Neck, Slip-On and Threaded. From that table, the orifice flange with NPS 8, Class 300 has an OD of 15" (381 mm), and the flange shall be furnished with a raised face 0.06" (1.5 mm).

can you tell me when tapered inlet orifice is required and when circular inlet is required.

i mean to say....received orifice plate is a restriction orifice.

i saw most Flow orifices are having tapered inlet

pls tell me when tapered is required and why

this orifice plate is concentric square edged orifice

Hi Guest,

Abdel Halim Galala, (hope I I have your name correct Abdel!) gave you the standards you should read.

It is not necessary to have a tapered hole orifice plate, if the plate is not flat, but has a taper on the hole/s on one side, the taper goes down-stream.

BTW the hole could also be tapered and circular! Just a case of definition!

But did you mean the plate has no taper on either face?

Just a thought, but if you read the code sent in by Abdel you will find all this out anyway. Good luck.

yes it is a concentric square edged orifice flate. it doesnt have any tapered in downstream side.

I asked you as, if there is no tapered then at downstream side turbulence will be more and this may cause damage in pipes wall day by day.

But our orifice is restriction orifice. Not measuring the flow but limiting the flow so that less flow goes to downstream.

if you know pls tell me, when tapered are required. in what condition tapered hole is required or it is related to construction features like concentric, ecentric and segmental.

thanks for your help Mr Abdel

Hi Guest,

You can check out the codes and design factor by checking the Code standard set for this type of equipment as listed by Abdel on a previous post.

Whatever the reason for the restriction plate, there is no need for any tapered hole/s downstream. If the pipes are designed to allow the orifice place then they will be able to take any 'extra turbulence as you described.

There should be less overall pressure on the downstream section of pipe after the plate is fitted. Or perhaps I should say, after the plate is fitted the downstream pipe will be dealing with less flow so, the overall flow pressure should be less.

If you have a plate which is flat on both faces then that is fine and it does not matter which way round it goes. If there was tapered venturi then the tapered side must be downstream, OK?

Sometimes if not always, when using a tapered venturi plate there is an arrow near the edge to point to the downstream, but as your plate is flat this does not apply in your case.

Good luck.