I. Valve Overview
Product Definition and Application
The non-rising stem resilient seated gate valve operates by rotating the stem inside the valve body to drive the gate up and down, enabling opening and closing. It is suitable for fluid pipelines in water supply and drainage, wastewater treatment, construction, petrochemical, food and pharmaceutical, and energy systems. It is primarily used to start or stop the flow of media and is not recommended for throttling control.
• Sealing Principle: The gate is fully encapsulated with high-performance rubber (such as EPDM or NBR). When closed, it forms an elastic seal with the flat-bottom seat, compensating for minor deformation and ensuring zero leakage.
• Advantages of Non-Rising Stem Design: The stem is concealed within the valve body, saving installation space—especially suitable for underground or space-constrained environments. It also prevents stem exposure and corrosion, extending service life.
Model Code Interpretation
Example: Z45X
• Z: Gate valve type
• 4: Connection method (flanged)
• 5: Structure type (non-rising stem, resilient seated)
• X: Sealing surface material (rubber seal)
II. Main Technical Parameters
Pressure Ratings
• Nominal Pressure: PN10 (1.0 MPa), PN16 (1.6 MPa), PN25 (2.5 MPa)
• Strength Test Pressure: 1.5×PN (e.g., PN16 = 2.4 MPa)
• Sealing Test Pressure: 1.1×PN (e.g., PN16 = 1.76 MPa)
Operating Conditions
• Operating Temperature: 0℃ ~ 80℃ (up to 100℃ for hot water configurations)
• Applicable Media: Water, oil, steam, coal gas, natural gas, and other non-aggressive fluids
• Body / Bonnet Material: Ductile iron (QT450-10), pressure-resistant and corrosion-resistant
• Stem Material: Stainless steel (2Cr13 / 304), corrosion-resistant and wear-resistant
• Gate: Ductile iron frame fully encapsulated with EPDM / NBR rubber, integrally vulcanized
Main Dimensions
• Nominal Diameter: DN50~DN600
• Flange dimensions (e.g., bolt hole count, outer diameter) and face-to-face length (L) comply with GB/T 17241.6 (cast iron pipe flanges) and GB/T 12221 (valve structural length)
III. Structural Features and Operating Principle
Structure
• Fully Encapsulated Gate: Rubber layer thickness ≥2 mm, completely isolates metal from media, corrosion-resistant with excellent elastic memory
• Flat-Bottom Flow Path: No groove design at the seat bottom, reduces debris accumulation, lowers flow resistance, and facilitates cleaning and maintenance
• Triple O-Ring Seal: Stem is sealed axially with three NBR O-rings, self-sealing under water pressure, eliminating the need for packing maintenance. A dust cover is installed at the top to prevent external contamination
• Brass Stem Nut: Integrated with the gate for smooth transmission and reduced operating torque
Operating Mechanism
The valve is operated by rotating the handwheel (or electric/pneumatic actuator), which turns the stem. The stem thread engages with the internal nut of the gate, converting rotational motion into vertical movement:
• Clockwise rotation: Gate descends → valve closes • Counterclockwise rotation: Gate ascends → valve opens
• Full Open Indicator: When the stem reaches its upper limit (fully open), it is recommended to reverse by half to one full turn to prevent thermal expansion lock-up
Corrosion Resistance and Hygiene
• The internal and external surfaces of the body and bonnet are coated with non-toxic epoxy resin (compliant with GB/T 17219 hygiene standards), suitable for drinking water and food/pharmaceutical applications
• Rubber sealing materials are certified for hygiene and do not contaminate the media
IV. Main Standards
• Structural Standards: GB/T 12234 (Wedge Gate Valves) CJT 262 (Resilient Seated Gate Valves)
• Test Standards: GB/T 13927 (General Valve Pressure Test) JB/T 9092 (Soft Sealed Gate Valve Reliability)
• Hygiene Standards: GB/T 17219 (Safety of Drinking Water Distribution Equipment)
• Connection Standards: GB/T 9113 (Flanges) GB/T 17241.6 (Cast Iron Pipe Flanges)
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