DUKER 451, Operating Instructions Manual, Page: 7 / 19

Issue 04 Düker GmbH
– www.dueker.de
page 7
5.2 Operational steps

Transport the valve to the point of installation in its protective packaging.

Remove all packaging materials from the valve.

Check valve for transportation damage. Damaged valves must not be installed.

Check coating for damages. The coating may be mended with a repair kit.

Ensure that only valves whose nominal pressure and connection dimensions correspond to the
use conditions are installed. See markings on the valve.

Before installing, the valve and the pipe must be cleaned to remove dirt and hard bodies.

Perform a functional test before installation: The valve must open and close correctly.

The mating flange of the pipe must be concentric and plane-parallel.

Butterfly valves can be installed irrespective of the direction of flow.

The preferred installed position is in a horizontal pipe with vertical stem and hand wheel facing
upwards.

The valve should have an adequate ground support.

The connection screws must be uniformly tightened crosswise.

To ensure the function and compliance with the drinking water hygiene standards, only original
Düker original spare parts may be installed.

When pushing the valve and the seals into an installed pipe, the distance between the pipe ends
must be that all connection faces and seals remain undamaged. The gap should not be larger
than necessary, to ensure no additional stresses in the pipe during installation.

The valve must be installed stress-free.
6 Functional description
The butterfly valve is a valve for controlling the flow of a fluid in a pipeline. The valve is installed in the pipe
with flange connections. The Düker butterfly valves have a flow optimized, double-eccentrically mounted
disc. The profile seal can easily be readjusted and easily replaced.
The disc is connected to the drive shaft and guided out of the housing. The bearing shafts run in mainte-
nance-free bearings. Through internal and external O-rings, the shafts are sealed.
The butterfly valve can be operated either with hand wheel, Düker installation kit, electric actuator and hy-
draulic or pneumatic rotary actuators. The stop of the slider-crank mechanism is adjustable for the end posi-
tion "CLOSED".
The use of extensions to increase the operating torque during hand wheel operation is not permitted as this
will damage the valve. The valve is closed clockwise and opened in the opposite direction.