NRS RESILIENT SEATED GATE VALVE ECONOMY PATTERN
Description
TECHNICAL DATA SHEET
ECONOMY PATTERN NRS RESILIENT SEATED GATE VALVE
Ductile Iron Body · Fully Vulcanized EPDM Wedge · Non‑Rising Stem
Typical Size Range: DN40 – DN600 (1½″ – 24″)
Pressure Class: PN10 / PN16
End Connection: Flanged to EN 1092‑1 / ASME B16.1 (Class 125 compatible)
1. GENERAL DESCRIPTION
This is an economy‑pattern, non‑rising stem (NRS) gate valve designed for cost‑effective isolation of water, wastewater, and neutral fluids. The body, bonnet and wedge core are made of ductile iron (DI), combining high strength with good ductility. The wedge is fully encapsulated with vulcanized EPDM rubber, providing a resilient seating surface that ensures bubble‑tight, zero‑leakage shut‑off in both flow directions without the need for a wedge‑pocket seat insert. The NRS design keeps the stem threads inside the pressure boundary, resulting in a compact assembly ideal for buried service, pumping stations, and plant isolation where headroom is limited. Standard exterior coating is a fusion‑bonded epoxy (minimum 250 µm) for excellent corrosion protection.
2. APPLICABLE STANDARDS
| Parameter | Standard |
|---|---|
| Design & Manufacturing | EN 1171 / BS 5163 (Resilient‑seated gate valves) |
| Face‑to‑Face Dimensions | EN 558‑1 Series 14 (basic series 14) |
| Flange Dimensions & Drilling | EN 1092‑1 PN10 / PN16 (or ASME B16.1 Class 125) |
| Pressure‑Temperature Ratings | EN 1092‑1 (DI material) / ASME B16.42 |
| Testing & Inspection | EN 12266‑1 (ISO 5208) / API 598 |
| Coating | EN 14901 (fusion‑bonded epoxy) – internal & external |
3. TECHNICAL SPECIFICATIONS
| Parameter | Value / Description |
|---|---|
| Valve Type | NRS, resilient‑seated, full‑bore, parallel‑sided (or wedge) gate valve |
| Nominal Diameter | DN40 – DN600 (1½″ – 24″) – consult factory for larger sizes |
| Nominal Pressure | PN10 or PN16 (specify) |
| End Connection | Flanged EN 1092‑1 PN10/PN16 – ASME Class 125 optional |
| Body & Bonnet Material | Ductile Iron EN‑GJS‑500‑7 (GGG50) / ASTM A536 Gr. 65‑45‑12 |
| Wedge Core Material | Ductile Iron EN‑GJS‑500‑7 |
| Wedge Encapsulation | Fully vulcanized EPDM rubber, seamless coating over entire wedge |
| Stem Material | Stainless Steel AISI 410 / 420 (or 304/316 on request), ground & polished |
| Stem Nut (Internal) | High‑strength Brass (C46400) / Bronze, integrated thrust collar |
| Bonnet Gasket | EPDM O‑ring (captured), providing maintenance‑free sealing |
| Bonnet Bolting | Zinc‑plated carbon steel, 8.8 grade (option: SS304) |
| Packing | Triple O‑ring seal (EPDM / NBR) – maintenance‑free, no gland adjustment required |
| Operation | Handwheel up to DN200; bevel gear operator standard for DN250 and above |
| Seat Leakage | Rate A – Zero leakage, bubble‑tight per EN 12266‑1 / API 598 |
| Coating | Epoxy powder coating, RAL 5015 blue (standard), min. 250 µm DFT internal & external |
| Service Media | Water, raw water, sewage, neutral liquids (EPDM not suitable for oils/hydrocarbons) |
4. MATERIALS OF CONSTRUCTION (Typical Economy Pattern)
| Part No. | Component | Material |
|---|---|---|
| 1 | Body | Ductile Iron EN‑GJS‑500‑7 (GGG50) |
| 2 | Bonnet | Ductile Iron EN‑GJS‑500‑7 |
| 3 | Wedge (Core) | Ductile Iron EN‑GJS‑500‑7 |
| 4 | Wedge Encapsulation | EPDM rubber (per EN 681‑1), fully vulcanized |
| 5 | Stem | Stainless Steel AISI 420 (1.4021) – rolled trapezoidal thread |
| 6 | Stem Nut | Brass CuZn39Pb3 (CW614N) or Bronze CuSn5Zn5Pb5 |
| 7 | Bonnet O‑ring | EPDM 70 Shore A |
| 8 | Stem Sealing System | Triple EPDM O‑rings with PTFE bearing bush |
| 9 | Bonnet Bolting | Carbon Steel Gr.8.8, zinc‑plated + clear passivation |
| 10 | Handwheel | Ductile Iron / Malleable Iron (smooth rim) |
| 11 | Gear Operator (opt.) | Enclosed bevel gear, ductile iron housing, grease‑filled |
Materials of wetted parts are WRAS / ACS / KTW compliant for potable water by request. EPDM is standard; NBR seat available for wastewater applications.
5. PRESSURE – TEMPERATURE RATING (DI Body, EPDM Wedge)
| Temperature (°C) | Max. Working Pressure (bar) – PN16 |
|---|---|
| –10 to +50 | 16.0 |
| +60 | 15.0 |
| +70 | 14.0 |
| +80 | 13.0 |
| +100* | 11.0 |
For continuous operation above 80 °C, the service life of EPDM may be reduced. Maximum intermittent temperature 100 °C. For hot water >80 °C, consult factory for alternative seat materials. These ratings are non‑shock and based on standard EN 1092‑1 for DI material group.
6. DIMENSIONS & WEIGHTS (Flanged PN16, EN 558‑1 Series 14)
| Nominal Size DN | Face‑to‑Face L (mm) | Height (Closed) H (mm) | Handwheel / Gear (mm) | Approx. Weight (kg) |
|---|---|---|---|---|
| 50 | 178 | 285 | 200 (handwheel) | 12.0 |
| 80 | 203 | 355 | 250 (handwheel) | 20.0 |
| 100 | 229 | 425 | 300 (handwheel) | 30.0 |
| 150 | 267 | 585 | 355 (handwheel) | 55.0 |
| 200 | 292 | 720 | 400 (handwheel/gear*) | 95.0 |
| 250 | 330 | 860 | 500 (gear) | 165.0 |
| 300 | 356 | 1010 | 500 (gear) | 240.0 |
Handwheel operation is standard up to DN200. Gear operator is recommended for DN200 and standard for DN250 and above. For exact dimensions, refer to the certified outline drawing.
7. TESTING & INSPECTION
| Test Type | Test Medium | Test Pressure | Acceptance Criteria |
|---|---|---|---|
| Shell Strength | Water | 1.5 × PN (e.g., 24 bar) | No visible leakage, no permanent deformation |
| Seat Closure – High Pressure | Water | 1.1 × PN (e.g., 17.6 bar) | Zero leakage (Rate A) – no visible drop for duration |
| Seat Closure – Low Pressure | Air / N₂ | 6 ± 0.5 bar (0.6 MPa) | Bubble‑tight, no leakage |
| Seat – Reverse Flow Direction | Water | 1.1 × PN | Zero leakage – valve bi‑directional |
| Coating Inspection | Visual | – | Uniform coverage, min. 250 µm, no pinholes |
All valves undergo 100 % shell and seat testing. Standard commercial test certificates are provided. EN 10204‑3.1 material certificates and additional testing are available as an option.
8. AVAILABLE OPTIONS & ACCESSORIES
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Pressure Class: PN10 (lighter flanges) or PN25 (limited sizes).
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Seat Material: NBR (nitrile) for wastewater and oily water (improved hydrocarbon resistance).
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Stem Upgrade: AISI 316 stainless steel for corrosive environments.
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Coating: Custom colours, WRAS‑approved epoxy for potable water, additional primer and topcoat.
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Operator: Bevel gear for all sizes (if torque reduction needed), chain wheel for overhead operation.
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Indication: Visual position indicator (rising flag) attached to the stem nut.
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Locking Device: Lockable handwheel in fully open or closed position.
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Extension Spindle: For buried service, with indicator plate and street cap.
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Certifications: WRAS / ACS / KTW for drinking water, PED 2014/68/EU (Cat. I), DNV / LR type approval on request.
9. ORDERING INFORMATION
To receive an offer, please provide the following information:
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Valve type: Economy Pattern NRS Resilient Seated Gate Valve
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Nominal size: DN _____
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Pressure class: PN10 / PN16
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Body & wedge material: Ductile Iron with EPDM wedge (or alternative seat)
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End connection: Flanged EN 1092‑1 (specify PN10 or PN16 drilling)
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Medium & operating temperature
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Operator: Handwheel / Gear / Chain wheel
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Special coating or certificates (e.g., WRAS, EN 10204 3.1)
This data sheet describes a standard economy‑pattern resilient‑seated gate valve suitable for general water and wastewater isolation. For special service conditions or project‑specific requirements, the manufacturer should be consulted for an engineered solution.
