Basics
for installing the device in a pipe
HON 5020 gas pressure regulator with HON 630 pilot
30
4.3
Meter run characteristics
The following recommendations are based on the measuring line connection conditions set
forth in standards (DIN)
EN
334 and (DIN)
EN
14382. The company operating the system is
the sole party responsible for the meter run working properly.
A pipe area with a steady flow pattern must be selected for the sensing point. There
must not be any components that disturb the flow directly upstream and downstream
of the sensing point, e.g., orifice plates, expanders, bends, junctions, shut-off devices,
etc.
The flow rate at the sensing point should not exceed approx.
25
m/s, depending on the
system conditions.
In the case of specific system circuits (such as
gas regulating lines for gas engines) and in
the case of gas burners, flow rates higher than 25
m/s may be allowed following con-
sultation with the manufacturer.
Within a low-pressure range of up to approx.
250
mbar, a maximum flow rate
of
approx.
15
to
20
m/s is recommended at the sensing point. On a case-by-case basis,
and following consultation with the manufacturer, even lower flow rates may be al-
lowed.
Depending on the specific system design, the L
uR
lengths of the undisturbed pipes upstream
of the sensing point must be (2.5
to
5)
x
DN of the pipe, with the specifics depending on the
gas pressure regulator model and whether or not there is a pipe expander downstream:
If …
and...
then...
A gas pressure regulator with an
expander that is part of the
device is used
The nominal size of the pipe is
equal to the outlet-side nominal
size of the gas pressure regulator
L
uR
min.
2.5
x
DN
The nominal size of the pipe is
the next larger standard nominal
size
L
uR
min.
3
x
DN
The nominal size of the pipe is
two standard nominal size
increments larger
L
uR
min.
4
x
DN
The nominal size of the pipe is
more than two standard nomi-
nal size increments larger
L
uR
min.
5
x
DN
A gas pressure regulator with
the same outlet nominal size as
the inlet nominal size is used
The nominal size of the pipe is
the next larger standard nominal
size
L
uR
min.
4
x
DN
The nominal size of the pipe is
two standard nominal size
increments larger
L
uR
min.
5
x
DN
Standards used as a basis
Conditions for the meter
run
Upstream of the sensing
point
