3
FLUID Temp.
Max. Pressure
Liquid
Air
(
o
F)
(
o
C)
PSIG
kPa PSIG
kPa
PVC
70
21
200
1379 100
690
100
38
100
690 50
345
125
52
75
517 35
241
150
65
50
345 25
172
POLYSULPHONE
230
110
250
1724 125
862
(Minimum temperature: -20
o
F.)
SELECTION TABLE
Each of the models carries scales for all media
shown
Maximum Flow Rates
Model
Water
Air
No.
90 PSI
FL-505
5 gpm
50 scfm
20 lpm
1400 slpm
FL-510
10 gpm
90 scfm
38 lpm
2500 slpm
FL-515
15 gpm
135 scfm
55 lpm
3900 slpm
FL-530
30 gpm
300 scfm
110 lpm
8000 slpm
FL-540
40 gpm
400 scfm
150 lpm
11000 slpm
FL-550
50 gpm
500 scfm
200 lpm
14000 slpm
HOW IT WORKS
Fluid enters at end marked “IN” and
forces the piston to move with it,
against spring pressure, enough to
pass given flow around piston
periphery. The knife edge of the
piston is visible through the
transparent housing; its position
under the printed scale gives the
flow rate.
Flow tube is PVC or polysulphone plastic
Installation
Inlet and outlet ends are marked on the flow meter body,
and an arrow on the printed scale indicates flow direction.
Insite flow meters can be mounted in any convenient
orientation (vertical, horizontal or anything in-between)
without affecting performance. The end fittings are con-
nected to the plastic body with O-ring sealed straight
threads and don't need to be highly torqued to prevent
leakage. These fittings accept pipe with tapered threads
(NPT). Teflon tape should be used on the pipe threads and
standard torques applied, to make leak-free connections.
Put your wrench only on the end fitting when piping on.
Do not apply wrenches on the plastic body alone when
connecting to pipe.
Many users find that a disconnect fitting, installed upstream
of the flow meter, makes for easier removal of the flow
meter, for cleaning internals. Control valves should be
installed downstream of the flow meters.
Two scales are provided. One for liquid and one for air/
nitrogen gasses. Air/nitrogen gas meters are calibrated in
SCFM. The air/nitrogen scale is calibrated at 90 PSI
pressure and 70
o
F temperature. If the flow meter is used
with air at pressures and/or temperatures that differ from the
above, correction factors can be applied to a 90-psi air scale
readings to get correct SCFM values. See Tables.
High pressure air vented to atmosphere through the Insite
flow meter may result in erratic readings. When used to
measure high pressure air, it is recommended that a vent
valve be installed downstream of the flow meter.
Maintenance
Normally, the only servicing required is a periodic cleaning
of the tube and three internal parts. Use wrenches on the
end fittings to remove the flow meter from the line. Do not
apply wrenches to the plastic body alone when
breaking pipe connections.
With the flow meter out of the line, completely remove the
end fitting from the outlet end of the tube. Use a bent wire
of other hook to grab the plastic shaft, piston and spring
and remove from tube. Inspect all parts for damage. The
interior of the tube can be swabbed out, and the parts
wiped off, with a soft dry cloth. If dirt or residue cannot be
removed with a dry cloth, use water and a mild non-
abrasive soap. DO NOT USE SOLVENT OF ANY KIND.
Replace any worn or damaged parts.
When reassembling the flow meter, be sure the piston is
installed as shown in the drawing. Don’t put in upside
down. Inspect O-rings for damage and replace if
necessary.
Correction factors when monitoring air flow at other
than 90 PSI at 70°F
TABLE 1 PRESSURE
PSIG 10 20 30 40 50 60 70 80 90 100
Factor .49 .58 .65 .72 .79 .84 .90 .95 1.00 1.05
TABLE 2 TEMPERATURE
Temp°F 30 50 70 90 120 150
Factor 1.04 1.02 1.00 0.98 0.96 0.93
When operating at a pressure other than 90 PSIG multiply
the applicable factor to the SCFM reading on the tube for
corrected SCFM reading.
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INLET
OUTLET
®
ENGINEERING, INC.
P. O. Box 4047, Stamford, CT 06907
FL-500 Series In-Line Flowmeters
and Switch Kits
