Instructions for Use
– SCHMIDT
®
Flow Sensor SS 23.400 ATEX 3
Page 10
almost zero while reaching its maximum w
N
in the pipe center (the opti-
mum measuring point)
.
This measuring value can be converted to an av-
erage speed
N
w
which is constant over the pipe cross-section by using a
correction factor, the so-called profile factor PF. This profile factor de-
pends on the pipe diameter
8
(details see flow calculator).
Thus, it is possible to calculate the standard volumetric flow of the medium
using the measured standard flow velocity in a pipe with known inner di-
ameter:
SCHMIDT Technology
provides a convenient calculation tool to compute
flow velocity or volume flow in pipes (circular or rectangle) for all its sensor
types and measuring ranges on its homepage:
Wall mounting
The wall mounting flange (520181) is designed for the installation of the
flow sensor
SS 23.400 ATEX 3
as an immersion sensor through a (locally
even) wall (e.g. wall of a flow box). In general, the flange differs from the
through-bolt joint only by the type of fastening on the wall. The threaded
bush included in the delivery has a broadened base provided with a plane
contact surface and two holes that allow a fast and easy installation by
means of two screws.
Apart from that all advantages, requirements and installation instructions
for the through-bolt joint regarding the stepless sensor installation apply
(see subchapter:
“Pipe-related flow”).
8
Both inner air friction as well as obstruction caused by the sensor is responsible.
D
Inner diameter of pipe [m]
A
Cross section area of pipe [m
2
]
N
w
Peak flow velocity in the middle of pipe [m/s]
N
w
Average flow velocity in the pipe [m/s]
PF
Profile factor (for pipes with circular cross-section)
EF
Measuring unit factor (conversion to non-SI units)
N
V
Standard volumetric flow [m³/s]
EF
A
w
V
w
PF
w
D
A
N
N
N
N
2
4
