DUKER 304 User manual

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Operating instructions
Underground fire hydrants
Type 304/305
- based on EN 1074-6, EN 14339
- completely enamelled inside and outside
- one-piece body, made of ductile cast iron
- DVGW registrated
Type 304 with single obturator
Type 305 with double obturator
Item No. of the operating instructions : 765355_01, Issue 04.2017, 14 pages
Subject to change without notice

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1. Intended use
2. Safety precautions
2.1. General safety instructions
2.2. User safety instructions
2.3. Special risks
3. Transport and storage
4. Installation into the pipeline
5. Description
5.1. Protection against pressurised water
5.2. Technical characteristics
5.3. Flow values
5.4. Performances
5.5. Operation
6. Dimensions
7. Drawing and parts list
8. Dismantling of the obturator linkage
9. Assembling of the obturator linkage
10. Maintenance and trouble shooting

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1. Intended Use
After the installation into a pipe system, shut-off valves are only intended for stopping or
allowing media to
pass within the range of the permitted operating conditions (temperature and pressure limit
"PN" labeling on
the valve, unless stated otherwise).
These valves are preferably intended for liquid media, such as drinking water, process water, raw and
waste water. Any deviating operating conditions or areas of application are subject to manufacturer
approval.
We will not assume any responsibility for consequential damage caused by
 unauthorized modification of the valve and the accessories supplied
 improper operating or operating conditions
 acts of God
Continuous operation of the valve in an intermediate position will lead to increased wear of the valve
or the subsequent pipe system up to total destruction and should therefore be avoided.
Cavitation can be identified among other things by:
 Increased noise level
 Crackling noise
 Severe vibrations
Cavitation can be avoided by operating the valve only in fully OPENED or fully CLOSED position.
2. Safety Precautions
2.1. General safety instructions
The same safety regulations apply for valves as for the pipe system in which they are installed. The
following instructions only include additional safety instructions to be observed for valves.
2.2. User safety instructions
The operator of the valve must ensure that the valve is only used in accordance with the intended use.
This is not the responsibility of the manufacturer. The valve may only be operated by properly qualified
and trained staff. The operating manual and the corresponding safety instructions must be read
and understood.
It is prohibited to use any valves with a nominal pressure ("PN") and maximum admissible operating
temperature insufficient for the operating conditions.
The approved range is indicated on the valve.
Warning: Temperatures below 10°C and above 40°C during work on the pipeline parts involve the risk of
injury. Protective measures must be taken accordingly.
Operating media must correspond to the specification of the valve. The manufacturer does not

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assume any liability for damage resulting from corrosion caused by aggressive media. Neglect of these
regulations may result in imminent danger to life and health, and may cause damage to the pipeline.
 The valve must be professionally installed into the pipeline.
 Following EN 1074-1, the maximum flow velocity may not surpass 4 m/s in continuous
operation.
 Operating conditions such as vibrations, water impact, erosion, cavitation and major
proportions of solid matter in the medium - especially of an abrasive nature – must be
clarified with the manufacturer prior to commissioning.
2.3. Special risks
Be sure to free the pipeline from any pressure and risk prior to disassembly, maintenance and repair of
the valve. During disassembly the medium may leak, therefore the pipeline and the valve must be
completely emptied.
The energy supply must be switched off.
For valves that are used as end valves, the free connection must be shut off or the valve locked securely
in the position "shut". Danger of Crushing!
3. Transport and storage
All valves must be carefully transported and stored.
The valves are fully enamelled or powder-coated. The coatings are shock-sensitive and must be
protected against impact stress.
The gaskets are sensitive to light: Unpackaged valves may only be exposed to bright daylight
or ultraviolet light for a very short time. This is why the openings are sealed with protective caps. Valves
must be stored in darkened rooms, in their original packaging with the protective caps.
In the event of storage over an extended period of time, the storage location should be frost-protected,
cool, dry, dark and free of dust. Alternatively, the valves may also be packed in order to fulfill these
conditions.
The valve should be stored on a pallet or similar support and only transported with suitable
tools such as wide straps to its designated point of installation. Do not use chains!

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4. Installation into the pipeline
For installation and operation of the hydrants consider the DVGW Leaflet W 331!
When installing the hydrant with the factory-provided flange gasket, the flange bolts should be tightening
with a max. torque of 70 Nm.
5. Description
5.1. Protection against pressurised water
Düker hydrants series 304/305 are equipped with the proven, automatic working protection against
pressurised water.
When opening the hydrant (main obturator), the pressurised water will flow into the hydrant only after the
draining outlet of the hydrant is safely closed.
When closing the hydrant, the drainage outlet will only be re-opened after the main obturator is safely
closed.
This construction avoids the flow of pressurised water through the drainage outlet, and residual water
remaining in the hydrant can be drained without problems into the surrounding soil. In order to ensure a
permanently safe and unhindered drainage, we recommend the use of drainage packages.
5.2. Technical characteristics
The underground fire hydrants Type 304 / 305 are designed to supply a minimum flow of 110 m³ per hour,
at an internal pressure loss of 1 bar.
The maximum allowable water flow velocity is 4 m/ s.
The residual rest water is lower than 80 cm3.
Connecting flange: DN 80 according to EN 1092-2
Soil covers: 0.80 m – 1.00 m – 1.25 m – 1.50 m
Factory test pressure: 24 bar
If the hydrant Type 305 (with double obturator) is used for supplying water in the pipeline, the maximum
flow velocity should not surpass 0.5 m/s (150 l/min.)
5.3. Flow values

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5.4. Performances
 Robust, one-piece obturator, completely covered with high grade Polyurethane elastomer.
 Obturator designed in flow-optimized shape.
 Automatic draining and protection against pressurised water safely guaranteed by inside enamelling
 Stem bearing maintenance-free by use of 2 O-Rings.
 Stem thread produced by rolling process, therefore highest protection against wear and tear.
 Protection during replacement of the obturator linkage by integral linkage locking device.
5.5. Operation
The hydrant will be closed by turning the stem in clockwise direction, actuation anti-clockwise opens the
hydrant. To open the hydrant fully, approx. 9 turns are necessary. Due to the fact that the obturator acts
radially, absolutely tight sealing can be achieved with low effort.
When open or closing the hydrant, always turn the stem to the perceptible contact of the
mechanical end stops. The maximum operation torque MOT up to 105 Nm is valid for both
directions of rotation. If the max. torques are reached without satisfying closing or opening,
the application of higher torques will not achieve a better tightness of the obturator and can
lead to a destruction of the coating of the end stops or the stem drive.
=> Throttling or intermediate positions of the obturator during water flow are not allowed!
To avoid to high pressure in the upper column, the hydrant should not be closed as long the valves of the
standpipe are closed.
Automatical draining:
The outlet of the automatical draining is opened, when the hydrant is closed. The complete draining of the
hydrant will be carried out within a drainage time of 2 – 3 minutes, depending on the column length (soil
cover) and the water absorbing capacity of the surrounding soil. (EN 1074-6: max. 10 minutes)
Protection against pressurised water:
When opening the hydrant (approx. 2 turns), at first the drainage outlet will be closed against the
pressurised water, due to the design of the obturator.
Further opening (approx. 1 turn) will open the water flow.

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6. Dimensions
Surface
box
DIN 4055

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7. Drawings and part list
7.1. Drawing

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7.2. Part list
Pos.
Part
Material
1
Obturator linkage, consisting of:
1.1
Obturator
DCI / PUR
1.2
Guide piece
Brass
1.3
Bar
Stainless steel
2
Bay
onet claw, consisting of:
2.1
Ba
y
onet claw
DCI
2.2
Ring
Brass
3
Body
DCI
4
Bonnet
DCI
5
Stem cap
DCI
6
Stem unit, consisting of:
6.1
Stem
Stainless steel
6.2
Bonnet nut
Brass
6.3
Sliding ring
Brass
6.4
Screening ring
Neoprene
6.5
O
-
Ring
NBR
6.6
O
-
Ring
NBR
6.7
O
-
Ring
NBR
7
Outlet cap
with chain
DCI
8
Hexagon screw M16x40
Stainless steel
9
Washer 16
Stainless steel
10
Closing plug
PE
-
LD
11
Stone protector
Steel /
EPDM
12
O
-
Ring
NBR
13
O
-
Ring
NBR
14
Safety ring
POM
15
Ball
(Double obturator)
Steel / EPDM
16
Marking
ring
Plastic
17
Cylindrical pin
Steel
18
Type label
Adhesive foil
19
Flange gasket
Stainl.
Steel / EPDM

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8. Dismantling of the obturator linkage
Note: For hydrants Type 304 (single obturator) the pipeline has to be unpressurised
before working on the obturator linkage!
For ordering the spare linkage, the necessary soil cover length of the column can be detected by the
number of the markings.
 Close the gate valve in front of the hydrant (only for Type 304 with single obturator).
 Close the hydrant and turn the stem back for approx. ¼ turns till the stem perceptibly strainless.
 Release the bonnet (Pos. 4) by removing both hexagon screws (Pos. 8).
 Lift the bonnet (Pos. 4) approx. 40 mm from the hydrant body, by turning the stem anti-clockwise.
 Fix the bonnet (Pos. 4) in this level by using spacers (for example wooden wedges or similar).
 Turn the stem (Pos. 6.1) in clockwise direction, until the obturator linkage is pulled out of the body
seat.
 Drive out the stem-bonnet-unit from the guide piece (Pos. 1.2) by turning the stem in anti-clockwise
direction.
 Remove safety ring (Pos. 14) and O-Ring (Pos. 13).
 Turn the obturator linkage (Pos. 3) approx. 30° anti-clockwise and pull it out.

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9. Assembling of the obturator linkage
 Insert the new spare linkage (Pos. 1) in the body (Pos. 3). Watch out that the wings of the guide
piece (Pos. 1.2), with unequal thickness, fit into the corresponding notches in the body (Pos. 3).
This ensures the safe function of the drainage system.
 Turn the guide piece (Pos. 1) for approx. 30° in clockwise direction till the wings of the guide (Pos.
1.2) are positioned directly over the guide notches of the body.
 Place safety ring (Pos. 14) to close the body openings.
 Fix the O-Ring (Pos.13) with some spots of lubricant (for potable water) in the corresponding groove
of the bonnet.
 Screw the stem-bonnet-unit clockwise in the guide piece (Pos. 1.2) until the bonnet is in contact with
the guide piece. Fix this bonnet position with the help of longer screws M16x75 or similar. Be sure
that the screws are well fixed in the thread holes of the body.
 Turn stem (Pos. 6.1) anti-clockwise, to press the obturator in the body seat. Then turn the stem
clockwise till the bonnet (Pos.4) contacts either the body (Type 304) or the guide piece (Type 305).
During this work please watch out for the correct placement of the O-Ring (Pos. 13).
 Replace the longer helping screws alternately with the original screws (Pos.8). Make sure that during
the exchange one screw is always safely in place and holds the bonnet in position.
The original screws shall be tightened with 75 Nm.
 Check the proper function and flush the hydrant, to bring out potential dirt, stones or similar.

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10. Maintenance and trouble shooting
Consider this chapter always together with chapter 5.5 (Operation)
Regular maintenance intervals on hydrants are not required. We recommend to control the
function, drainage and tightness of the hydrant at the latest every 4 years.
We refer to the DVGW Leaflet W 392, Table 2, No. 2.
When flushing the hydrant, in any case the use of a standpipe with connected hose to
discharge the flushing water is necessary. Never flush the hydrant free into the surface box.
In case of flushing of the hydrant without standpipe, dirt and pollution from the surface box
can be sluiced into the hydrant and create problems with the water hygiene or plugging the
drainage outlet.
To avoid the generation of to high pressure in the upper part of the column, never close the
hydrant while the side valves of the standpipe are closed.
Furthermore please observe the procedure for the operation of underground fire hydrants,
which is given in annex “A” of the DVGW Leaflet W 331.
Turning the stemcap anti-clockwise will open, whereas turning clockwise will close the
hydrant.
To operate the hydrant the use of operation keys according to DIN 3223 is recommended.
The keys are designed to ensure that normal manual force is sufficient for operation.
The additional use of key extensions to increase the operation torque s not allowed as this
will damage the valve internally.
Hydrants are open-close valves and not designed to regulate the water flow. To avoid
excessively high flow verlocities or cavitation, the obturator should always be opened up to
the mechanical end stop "Open" even during flushing. As a rule, the side valves of the
standpipe or distributor must be used to regulate the flow rate.
=> Throttling or intermediate positions of the obturator during water flow are not
allowed!
To guarantee the proper function and the adherence to the hygienic
requirements for potable water, the use of Düker genuine spare parts is
stipulated.
The distribution and reproduction of these Operating Instructions, utilization and communication of their contents to
others is authorized exclusively for the purpose of ensuring the correct installation and operation of the Düker product
treated in the document. For all other purposes, distribution, reproduction and utilization of the contents, also in
excerpts, is prohibited. Offenders will be held liable for the payment of damages. All rights reserved in the event of
the grant of a patent, utility model or design.