24
Designs, materials, weights and performance ratings are approximate and subject to change without notice. Visit
armstrong
international.com for up-to-date information.
Installation Overview – continued
Installing Flow Meters with a Compression Connection*
Use the following formula to determine insertion length for flow meters (NPT and flanged) with a compression process
connection. The installation procedure is given on the next page.
Where:
I = Insertion length.
S = Stem length – the distance from the center of the sensor head to the base of the enclosure adapter (S = 29.47
inches for standard probes; S = 13.1 inches for compact; S = 41.47 inches for 12-inch extended).
F = Distance from the raised face of the flange or top of NPT stem housing to the outside of the pipe wall.
R = Pipe inside diameter, divide by 2 for pipes ten inches and smaller.
R = Five inches for pipe diameters larger than ten inches.
t = Thickness of the pipe wall. (Measure the disk cut-out from the tapping procedure or check a piping handbook
for thickness.)
Example:
To install an AVI meter with a standard probe (S = 29.47 inches) into a 14 inch schedule 40 pipe, the
following measurements are taken:
F
=
3
inches
R
=
5
inches
t
=
0.438
inches
The insertion length for this example is 21.03 inches. Insert the stem through the fitting until an insertion
length of 21.03 inches is measured with a ruler.
*All dimensions are in inches
Figure 2-6. Insertion Calculation (Compression Type)
Insertion Length Formula
I = S – F – R – t
S
S
I
I
F
F
R
R
t
t
