Resilient Seated Non-Rising Stem Gate Valve – Müller

Mô tả

A non-rising stem gate valve is a gate valve design where the valve stem remains stationary and does not rise or fall during operation.
During operation, the stem remains inside the valve body. The operator only sees the handwheel or operating cap rotating in place, while the moving parts are inside the valve.
Construction:
– Valve body: Made of ductile iron (GGG40/50), featuring a smooth internal bore design without grooves at the bottom. This helps prevent the accumulation of debris and sand at the valve sealing point.
– Valve disc: This is the most critical component, made of ductile iron and fully encapsulated with high - quality EPDM rubber. This "resilient seated" design ensures a tight shut - off even when small impurities are present in the flow.
– Non - rising stem: When the handwheel is operated, the valve stem only rotates to raise or lower the valve disc without moving upward or downward outside the valve body.
– Valve stem: made of stainless steel (SS304/420) with high mechanical strength and excellent corrosion resistance.
– Stem sealing gasket: A multi - layer O - ring sealing system prevents water leakage to the outside and can be replaced even while the valve is under pressure (depending on the model).
Technical specifications:
– Sizes: DN50–DN600 (most commonly DN50–DN300)
– Working pressure: PN10 / PN16 / PN25 (depending on manufacturer)
– Material:
+ Valve body: Ductile iron GGG50
+ Valve bonnet: Ductile iron
+ Valve disc: Ductile iron with EPDM rubber coating for resilient seating
+ Valve stem: Stainless steel (SS304 / SS316)
+ Sealing gasket: EPDM / NBR
+ Bolts: Galvanized steel or stainless steel (depending on manufacturer)
– Coating:
+ Epoxy coating inside and outside ≥ 250 µm
+ Corrosion resistant, compliant with potable water standards
– Working temperature: -10 to 80°C
– Application media: Potable water, light wastewater, fire-fighting water, technical/industrial water
Key Characteristics:
– During operation, the stem does not rise, saving space and making it suitable for underground installation, valve chambers, cabinets, and confined piping systems.
– High tightness with zero leakage, compliant with EN 12266-1 and DIN 3230 standards
– High mechanical strength, with better pressure and impact resistance compared to gray cast iron.
– Enhances durability when operating in submerged conditions, preventing stem jamming and corrosion.
– Provides corrosion protection and extends service life.
– For DN200 and above, a gear operator is commonly integrated to facilitate easier operation.
Applicable standards:
– Design and manufacturing: DIN 3352
– Face-to-face dimension: DIN 3202 F4 / F5
– Flange standard: BS EN 1092-2:1997
– Epoxy coating: DIN 30677 / ISO 12944
Benefits:
– Excellent tight sealing performance: Thanks to the resilient rubber - coated valve disc, the valve provides 100% tight shut - off (zero leakage), making it suitable for potable water standards.
– Space - saving design: The non - rising stem design allows the valve to maintain a fixed height, making it especially useful for installation in confined valve chambers beneath sidewalks or roadways.
– Low operating torque: The rubber-coated valve disc reduces friction during opening and closing, allowing for smoother and easier operation.
– Full bore design: When fully opened, the gate is completely lifted out of the flow capacity with virtually no pressure loss.
Disadvantages: 
– Difficult to identify valve position: Since the stem does not rise, operators cannot visually determine whether the valve is open or closed (an additional position indicator is usually required if needed)
– Temperature limitation: Due to the rubber-coated disc design, it is not suitable for steam service or high - temperature media above 100°C.
Applications 
– Urban clean water supply network system
– Water supply and wastewater treatment pumping station
– Fire protection system
–High-tech irrigation and agricultural systems
– Drainage and wastewater treatment system