Flanged water meters / flow meters, DN40-400-
IP65/68
-CE – Operating Manual
Page 13 of 19
8.2 Install stop valves upstream and downstream of the irrigation flow meter connections to enable isolation
from the water for removal of the irrigation flow meter or its measuring insert for inspection or repairs.
8.3 The piping route geometry at the installation location must prevent air blocks from forming within the
installation length of the irrigation flow meter. The irrigation flow meter must remain completely filled with
water, so there must not be a drop in the downstream direction of the pipework (see Fig. 2).
Fig. 2. Flow meter installation
8.4 For protection against the negative effects of water flow turbulence due to bends, valves, and other
system components, the upstream side can have a straight section with a length of L=5DN (the DN of the
flow meter). If the flow meter is to be installed downstream of a double bend, a check valve, or a pump,
double the specified upstream straight piping section length as follows: 2L; if the turbulence-generating
component is a piston pump, triple the length: 3L. To avoid an upstream straight piping section this long, a
flow vane can be installed upstream of the irrigation flow meter. The downstream straight piping section
length for the irrigation flow meter must be: L
1
= 3DN.
8.5 All connections with the installed irrigation flow meter must be in accordance with good practice. Install
all seals concentric to the piping bore centreline. It is not permitted to install the irrigation flow meter offset
(eccentrically) from the pipe centreline, and especially to have the pipe-to-flow meter seals offset and
obstructing the pipe bore, as this may cause turbulent flow.
8.6 The water flow through the irrigation flow meter must be in the direction shown by the flow arrow affixed
to both sides of the guard. The stop gate valves, if installed upstream and downstream of the irrigation flow
meter, must be fully open while the water is flowing.
8.7 When commissioning a new water supply system or repairing pipework before installation of an irrigation
flow meter, the pipework to be connected to the meter must be thoroughly flushed to remove all debris and
contamination which could damage the flow meter.
8.8 The irrigation flow meters must be secured to the pipework with bolts and washers in a size compatible
with the flange bolt holes.
Irrigation flow meter
