OPERATING MANUAL
07-2022
9/14
When installing eccentric butterfly valves downstream of the control valves (e.g. Product Number
6800)
and shut-off valves (e.g. needle, ball or poppet valves), a minimum distance of 10xDN of the valve must be
kept between them.
Due to the non-uniformity of the speed and pressure fields near piping elbows and tees, it is recommended
to maintain a straight piping run at least 3×DN long between the valve outer flange face and the piping bend
or tee (see picture below). The manufacturer allows for a distance less than 3xDN, but this may result in
noisy operation and faster wear of the butterfly valve.
Fig. 8. Recommended distances from the piping bends
The general rule is not to install the valve near any bend or tee or any piping bends (elbows / tees), especially with
the valve on the high-pressure side of the piping (in the pump to valve to piping curve system)
The normal flow deflection over a piping bend will be aggravated by the low-pressure area of the valve (where a
risk of flow interruption exists). Installation directly behind pumps, behind elbows or tees is not permitted due to
the possibility of cavitation on the flap surface, vibration or disc oscillation and faster wear of bearings and sealing
elements. The dimensions of the valve must also be taken into account in the technical design so that the valve can
be operated freely.
The butterfly valve can be installed in any orientation and in either direction of flow, provided that the butterfly
valve closure pivot shafts are aligned horizontally. Correct installation of the valve on vertical and horizontal
pipelines is given below -
Fig. 9.
The permissible deviation from the horizontal location of the shafts in relation
to the horizontal axis of the pipeline is from 2 to 5 degrees.
Fig. 9. Orientation of the valve closure pivot shaft relative to the piping plane shown for
Product Number
4493 DN500
a)
Vertical piping
b)
Horizontal pipeline
