The German standard DIN EN 593 PN16 and PN25 triple offset metal hard seal flanged butterfly valve is an industrial isolation valve engineered for European-standard pipeline systems where reliable metal-to-metal shut-off, elevated temperature capability and DIN EN 593 compliance are required on critical process lines. Manufactured by Trekre Valve at our Wuxi production facility, this double-flanged butterfly valve conforms to German DIN flange dimensions and incorporates triple-eccentric disc geometry with metal hard seat sealing for dependable performance in steam distribution, hydrocarbon transfer, chemical process branches and general utility headers across European EPC projects and export installations referencing German valve standards.
Compared with resilient-seated wafer designs, the double-flange body provides a stable pipeline connection on both sides, supports higher pipe loads on large nominal sizes and simplifies installation of spectacle blinds, spacers and maintenance spools without disturbing the opposite flange joint. The triple-offset disc path lifts the sealing surface away from the seat during the opening stroke, reducing friction, minimizing wear on high-cycle lines and extending service life under differential pressure when the valve remains closed for extended periods. German standard butterfly valves in this series are widely specified in petroleum, chemical and industrial environmental water treatment, high-rise building supply and drainage pipelines where DIN-rated flanged connections govern the piping specification.
Construction and sealing design
Connection type: double flange (flanged ends both sides) per DIN EN 1092-1 PN16 and PN25 raised face; PN40 pressure stage available when project specifications require higher rating on selected nominal sizes.
Structure: triple eccentric (triple offset) disc geometry with oblique cone seat; one-piece stem with blowout-proof lower bearing and adjustable upper gland packing; disc rotation 90° for full open or closed position. The main structural features of the German standard series include both wafer-type and flange-type configurations within the broader product family, with this model supplied as a full double-flange end type for stable pipeline anchoring.
Sealing form: metal hard seal with a multi-layer sealing structure. Confirm the actual sealing materials, pressure-temperature limits and required shutoff performance for the selected assembly. The valve seat sealing ring adopts a laminated metal architecture that maintains shut-off integrity on steam, thermal oil and abrasive slurry media where elastomer liners cannot maintain long-term sealing performance. When the valve opens, the butterfly plate does not contact the sealing seat, eliminating uneven load on the sealing seat, extending service life and ensuring repeatable closure performance on isolation duties.
Operation: worm gear manual operator as standard on sizes from DN150 upward; hand lever on smaller bores; pneumatic double-acting or spring-return actuator and electric multi-turn or quarter-turn actuator available for remote or automated operation on request.
Body material: carbon steel GP240GH (1.0619), low-temperature carbon steel, alloy steel for high-temperature service, or austenitic stainless steel 1.4408 (316) and 1.4308 (304) castings for corrosive process fluids.
Disc and stem: stainless steel 304/316 disc with optional Stellite hardfacing on the sealing edge; stem in SS416, SS304 or SS316 with surface treatment for wear resistance against metal seats and blowout-proof retention in the body.
Nominal size and pressure rating
Nominal diameter range: DN50 through DN1200 depending on pressure class, seat design and actuator torque envelope. Primary pressure ratings are PN16 and PN25 per DIN EN 593; PN40 configurations are available on selected sizes when differential pressure, steam temperature or project piping tables require a higher pressure stage. Face-to-face length follows DIN EN 558 Series 13/14 tables and is confirmed against project isometric drawings before shipment.
For saturated and superheated steam service above 200 °C, metal-seated configurations with extended gland packing, heat dissipation fins on the stem seal area and graphite-based packing materials are recommended to protect stem seals from thermal degradation. The PN16 and PN25 ratings indicate suitability for general process fluids, compressed air, cooling water and steam within the temperature and pressure envelope defined by DIN valve standards and confirmed by hydrostatic and seat closure testing at the factory.
When selecting between metal hard seal and resilient seat variants on adjacent pipeline sections, consider the minimum operating temperature, required leakage class per EN 12266 or ISO 5208, and whether the valve will operate in modulating throttling positions where cavitation or velocity erosion may occur at partial openings. Triple-offset geometry is particularly advantageous for metal-seated German standard applications because the disc lifts off the seat immediately at the start of the stroke, reducing friction and galling on frequently cycled isolation points.
Triple offset geometry and DIN EN 593 compliance
Conventional concentric or double-eccentric butterfly valves rely on elastomer liners or PTFE seats that degrade under steam temperatures, oxidizing process gases and abrasive particulates in slurry service. The triple offset path creates a conical closure line where disc and seat contact occurs only in the final degrees of stroke, producing a camming action that wipes the sealing surface clean while avoiding the continuous sliding wear typical of lined discs. This design delivers high temperature resistance, wear resistance and corrosion resistance across demanding industrial media.
Trekre manufactures this German standard double flange butterfly valve family in accordance with DIN EN 593 design practice for flanged end types, DIN EN 558 face-to-face dimensions and DIN EN 1092-1 flange connections. Shell hydrostatic test, seat closure test and operational torque verification are performed before shipment. Material certificates for body castings, seat ring hardfacing records and pressure test reports are available for project turnover packages and third-party inspection on EPC contracts.
The product adopts a three-dimensional eccentric oblique cone valve seat, and the butterfly plate seal uses a precision metal sheet inlay matched to the seat cone angle. When the valve closes, the disc rotates and compresses the seal with increasing contact pressure near the final stroke; when opening, the seal separates completely from the seat, ensuring the sealing surfaces do not slide against each other under full differential pressure. This design reduces operating torque compared with double-eccentric metal-seated valves and supports predictable worm gear and actuator sizing across the full bore range.
Drive methods and actuation
Worm gear manual operation is the conventional drive method for German standard PN16 and PN25 double flange butterfly valves in sizes from DN150 upward, reducing handwheel input torque and providing a positive position hold under pipeline differential pressure. The gear unit includes a mechanical position indicator and adjustable stop limits at 0° and 90° disc rotation. For frequently cycled or remotely operated lines, pneumatic actuators deliver fast on/off response and are widely used in petrochemical and power plant utility systems. Electric actuators support 4–20 mA modulating control, open/close limit feedback and bus communication for integration with DCS or PLC platforms.
Actuator sizing must account for valve break torque at maximum differential pressure, safety factor and local ambient temperature limits. The worm gear housing is typically cast iron or aluminum with grease-lubricated worm and wheel gears; gear ratio is selected to keep handwheel rim force within ergonomic limits for the nominated valve size and pressure class. Bare stem ISO 5211 high-platform configurations accept direct-mount electric and pneumatic operators without modifying flange dimensions specified in contract drawings.
Applicable working conditions and industries
This German standard DIN EN 593 PN16 PN25 triple offset metal hard seal flanged butterfly valve is specified for steam headers, condensate return lines, hydrocarbon transfer, chemical process isolation, pulp and paper white liquor systems, district heating branch connections, cooling water circuits and environmental water treatment plants where DIN-rated flanged valves are the governing connection standard. Metal hard seated versions handle superheated steam, thermal fluids and abrasive slurries at temperatures typically up to 425 °C depending on body and trim materials.
Typical industries include thermal power plants, combined heat and power facilities, refineries and chemical complexes with European OEM equipment packages, LNG and gas processing utility skids, food and beverage steam circuits (stainless steel body variants), municipal energy stations and high-rise building HVAC and fire protection systems referencing German valve standards. The double-flange format supports stable connection on both pipeline sides, integration with spectacle blinds and maintenance spools, and removal for shop repair when adequate flange gap is provided during piping design.
For mixed-standard projects referencing both DIN and ANSI connections, Trekre can supply companion adapter spools and confirm face-to-face dimensions against DIN EN 558 and EN 593 tables to simplify multi-vendor piping coordination on EPC contracts. When bidirectional flow is required, specify triple-offset disc geometry with symmetrical seat loading so the valve maintains rated shut-off performance regardless of flow direction.
Product parameters
- Valve type: German standard DIN EN 593 PN16 PN25 triple offset metal hard seal flanged butterfly valve
- Model reference: D343H-PN16 / D343H-PN25 (project-specific)
- Size range: DN50–DN1200
- Pressure rating: PN16 / PN25 / PN40 (selected sizes)
- Body: GP240GH, LCB, WC6, 1.4408, 1.4308
- Disc: stainless steel with metal seat or Stellite hardfacing
- Stem: stainless steel 416/304/316, blowout-proof, adjustable packing
- Operation: worm gear / hand lever / pneumatic / electric actuator
- Design standard: DIN EN 593, DIN EN 558, DIN EN 1092-1
- End flange: DIN EN 1092-1 PN16/PN25 RF
- Test standard: EN 12266, ISO 5208
- Leakage class: metal seat EN 12266 permissible rate; fire-safe option on request
Selection and installation notes
Confirm DIN EN 1092-1 PN16 or PN25 flange facing (raised face), bolt circle, gasket type and pipeline stress loads before ordering. For steam applications, install with the stem horizontal or at a downward inclination to prevent condensate accumulation in the packing chamber. Allow clearance above the worm gear or actuator for maintenance access and handwheel rotation. When mating to non-DIN flanges, provide adapter spools rather than forcing bolt alignment, which can distort the body and compromise seat sealing.
Trekre Valve application engineers can review your medium analysis, design temperature and cycle frequency to recommend metal seat trim, fire-safe configuration and the appropriate actuator sizing data for your project documentation package. Each German standard DIN EN 593 triple offset flanged butterfly valve undergoes shell hydrostatic test, seat closure test and operational torque verification before shipment from our Wuxi factory. Material certificates, dimensional inspection reports and torque tables are available for distributor stocking, OEM integration and project procurement.
Frequently Asked Questions
How should I specify PN16 or PN25 for this valve?
Use the designation required by the approved piping specification and provide the actual operating conditions. Confirm the selected valve rating and companion flange arrangement rather than assuming the options are interchangeable.
Which face-to-face dimension should I use for a DIN replacement?
Send the required dimensional series or existing measured installation dimensions and request the selected drawing. A general DIN or EN designation alone does not establish the exact replacement length.
Can the metal seat be selected from temperature alone?
Also provide the medium, pressure, differential pressure and required shutoff duty. Request confirmation of the complete body, seat and trim arrangement and its documented limits for the order.