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NAF Duball DL Ball Valves NFENIM4163-00-A4 05/17
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Incorrect installation
Correct installation
Figure 1: Schematic lifting of a valve with mounted actuator. Note that
the final lifting of the valve into a vertical pipe requires different lifting
points.
2 Lifting
All lifting must be carried out on the valve itself and not on the
actuator. The mounting connection between the valve and the actuator
is designed principally for carrying the operating torque and the
deadweight of the actuator and is not designed to support the weight
of the valve. See Figure 1.
3 Receiving Inspection
All valves leaving our facility are inspected and tested in accordance
with the relevant requirements or in accordance with the special
provisions specified by the purchaser. Valves equipped with actuators
are subjected to functional testing and are adjusted in such a manner
that every unit is ready for direct installation in the pipework. However,
NAF always recommend that a receiving inspection is to be carried out.
We suggest the following inspection procedure:
• Check that the valve delivered is correct in terms of type, size,
equipment, etc.
• Examine the valve, actuator and valve positioner for possible damage
that may have occurred during transport.
4 Installation
Before installing the valve, please ensure that:
• The pipework is free from impurities
• The pipe end connectors between which the valve is to be installed are
parallel and are correctly aligned
• The distance between the pipe ends correspond to the valve length,
including gaskets.
The valve must not be used for pulling together or aligning incorrectly run
pipes as this will cause improper loads on the valve and pipe which could
lead to severe problems during operation. See Figure 2.
Figure 2: Ensure that the pipe ends align and have the correct gap
A typical application for the NAF Duball DL Pocket Valve is when it’s installed
in the reject pipe of a sand separator. See Figure 3. Make sure that the valve
is mounted in the correct flow direction as indicated by the flow arrow on
the valve body.
NAF strongly recommend that a Duball DL valve is installed upstream of
the Pocket Valve. This valve is to be open in normal operation and only shut
when the Pocket Valve is to be inspected/serviced.
If not supplied by NAF, two on/off valves should be installed on each of
the flush connections (1 & 2 as shown in Fig. 3) in close proximity to the
Pocket Valve. The Pocket Valve and the on/off valves should be operated as
described in Section 5, “Operating sequence”.
The pipes should be supported on each side of the valve
in order to
relieve the valve of unnecessary loads and avoid vibrations.
The actuator used on the Pocket Valve should be supported
in order
not to introduce unnecessary loads and to minimize any potential
influence from vibration.
Locate the valve so it will be easily accessible
for inspection and
service.
