Flow Orifices


Thread Starter

Bruce Axtell

I have been searching for a source of orifices in standard pipe sizes. I have looked in Thomas Register, etc., but haven't found anyone who manufactures a simple, inexpensive orifice like I need.

So far, I have been manufacturing them myself.

These are simple 1" NPT pipe nipples 4" long. I cut them in half, and then weld them back together with a metal disk inserted between the two halves.

The disk has a .07" pilot hole in it, which I use for the lowest flow. I then bore it out to the proper diameter for higher flows.

On both sides (and adjacent to) of the disk, I drill a hole for a 1/8" SS tube about 3" long, which is welded in.

The two holes are offset by about 20 degrees, so I can put tubing fittings on them without them hitting each other, because they are right next to the disk, and separated only by the thickness of the disk.

This gives me a nice orifice which I can pipe into an airline and measure the differential flow across the orifice.

The material must be stainless steel, though brass would also be acceptable.

It is used only for air at relatively low pressures (about 7-10PSI drop across the orifice, maximum, at a pressure of up to 100 PSI in some applications, though most are about 10"w.c.).

I can email a sketch or drawing to anyone who can supply these at a reasonable cost. Current annual usage is relatively low volume...maybe 50 or so.

Does anyone know where such an orifice can be commercially purchased? I can provide further specs, as required.

Thanks in advance.

Bruce Axtell
Engineered Control Systems, Inc.
763-712-5477 fax
[email protected]

Richard King

Hi Bruce,
I am not sure of the cost, but have a look at the Fisher-Rosemount "Integral Orifice - Model 1195". It is designed for small flows / Pipe Dia. (Other vendors will have something similar and maybe cheaper)

Richard King.

Alesa Alusuisse Engineering Australia Pty Limited.
Phone: +61 7 3218 3555
Fax : +61 7 3236 0155
Email: [email protected]
Web : http://www.alesa.com.au

Vitor Finkel


I recall to have purchased "Integral orifices" as they were named, a long time ago from Foxboro, Foxboro, Massachussets.

Vitor Finkel [email protected]
P.O. Box 16061 tel (+55) 21 285-5641
22222.970 Rio de Janeiro Brazil fax (+55) 21 205-3339