Deutsch
EnglishUnderground Hydrant 304 and 305
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Underground hydrants of the 304 and 305 series correspond to the requirements and tests of DIN 3221, DIN 3321 and EN 14339, as well as the DVGW testing standard VP 325 and possess a DVGW type approval test.
All materials used correspond to the KTW recommendations of the Federal Environmental Agency and the DVGW worksheet W270.
Furthermore, the requirements of the standard are even exceeded in many areas, such as the amount of residual water of 10 cm3 for example (standard requirements: ≤ 80 cm3) or the flow rate at 132 m3/h (standard requirement: ≥ 110 m3/h).
Upon request, the hydrants may be serially equipped with a self-locking, epoxy coated stainless steel outlet cover.
The most important elements
- inside and outside enamelled one-piece body
- cast-on and fully enamelled drainage outlet
- factory-mounted EPDM flange gasket with a steel core
- dual shut-off with an EPDM coated steel ball (305)
- obturator with full polyurethane elastomer coating
- solid stainless steel obturator linkage
- brass guide piece
- well-established and proven stem bearing
- self-acting EPDM stone protector
- DIN outlet coupling with brass ring and cast protective cover with stainless steel chain
Materials and technical properties
The one-piece body of the underground hydrant type 304 or 305 is made of ductile cast iron and is fully enamelled. The sturdy obturator is also made of cast iron. Its shape allows ideal flow-through conditions and it is further fully coated with premium hydrolysis resistant polyurethane.
The design of this underground hydrant supports water pressure protection according to DIN 3321. Once the hydrant is opened, the pressurized water will not enter the pillar from the main pipe before the drainage outlet of the pillar is locked.
Following that same pattern, the drainage outlet will not open during the shut-off procedure until the main valve is securely locked. This prevents the leaking of pressurized water and allows the remaining residual water to discharge.
Type 304 comes with a single shut-off and type 305 comes with a dual shut-off device. An additional sealing ball ensures sealing when the linkage is replaced under pressure. There is no need for the pipe to be without pressure due to the dual shut-off device and no additional gate valve is required.
Maintenance-free stem bearing as a result of using two O-rings. The rolled stem thread ensures high wear resistance. If repair is needed, the marking on the top of hydrant indicates information about the pipe covering in order to find the appropriate linkage length. The standard linkage safeguarding arrangement ensures additional safety during linkage
exchange.
Installation and operation to be carried out in accordance with the guidelines of the DVGW
worksheet W 331.
