NRS Cast Iron Gate Valve Metal Seated
Description
TECHNICAL DATA SHEET
NON-RISING STEM (NRS) CAST IRON GATE VALVE
Metal Seated · Bolted Bonnet · Solid Wedge
Typical Size Range: DN40 – DN600
Typical Pressure Class: PN10 / PN16
End Connection: Flanged to EN 1092-1
1. GENERAL DESCRIPTION
Non‑rising stem, bolted bonnet gate valve with metal-to-metal seating surfaces. The cast iron body and bonnet provide a cost‑effective solution for general industrial applications. The NRS design keeps the stem threads inside the pressure envelope, resulting in a compact assembly that requires less headroom than a rising stem valve. The metal seated wedge ensures reliable shut-off in services where soft seals would degrade, such as higher temperatures or media carrying suspended solids. Minimal allowable seat leakage per API 598 Rate C/D is inherent to metal seated construction; this valve is not intended for bubble‑tight zero‑leakage service unless a resilient‑seated version is selected.
Typical services include:
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Hot and cold water
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Steam (low‑pressure, saturated)
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Non‑corrosive oils and hydrocarbons
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Neutral gases and compressed air
2. APPLICABLE STANDARDS
| Parameter | Standard |
|---|---|
| Design & Basic Dimensions | BS 5150 / EN 1171 (Cast iron gate valves) |
| Face‑to‑Face Dimensions | EN 558‑1 Series 8 (short) – Series 15 (long) optional |
| Flange Dimensions & Drilling | EN 1092‑1 PN10 or PN16 |
| Pressure‑Temperature Ratings | EN 1092‑1 (material group cast iron) |
| Testing & Inspection | API 598 / ISO 5208 |
| Marking | EN 19 |
3. TECHNICAL SPECIFICATIONS
| Parameter | Value / Description |
|---|---|
| Valve Type | NRS, bolted bonnet, solid wedge, metal seated gate valve |
| Nominal Size Range | DN40 to DN600 (1½″ – 24″) – larger sizes upon request |
| Nominal Pressure | PN10 or PN16 (specify when ordering) |
| Body & Bonnet Material | Cast Iron ASTM A126 Class B / EN‑GJL‑250 (GG25) |
| Wedge (Disc) Material | Cast Iron ASTM A126 Class B / EN‑GJL‑250 |
| Seating Surface Type | Metal seated – integral cast iron seats or renewable seat rings (bronze / SS) |
| Stem Material | Stainless Steel (AISI 410/420) or Brass (C46400) |
| Stem Thread | Inside body – isolated from packing by thrust collar |
| Bonnet Gasket | Compressed synthetic fibre or graphite with binder |
| Packing | PTFE‑impregnated graphite / Flexible graphite / Aramide fibre |
| Gland & Gland Flange | Cast Iron or Ductile Iron |
| Bolting (Bonnet) | Steel, zinc plated (option: stainless steel) |
| Operation | Handwheel up to DN150; gear operator standard from DN200 |
| Leakage Class (Metal Seated) | Rate C or D per API 598 (maximum allowed leakage for metal‑seated valves) |
4. MATERIALS OF CONSTRUCTION (Typical)
| Part No. | Component | Material Standard / Grade |
|---|---|---|
| 1 | Body | Cast Iron ASTM A126 Cl. B / EN‑GJL‑250 |
| 2 | Bonnet | Cast Iron ASTM A126 Cl. B / EN‑GJL‑250 |
| 3 | Wedge (Disc) | Cast Iron ASTM A126 Cl. B / EN‑GJL‑250 |
| 4 | Body Seat Ring* | Bronze C83600 / CuSn5Zn5Pb5 – or Integral Cast Iron |
| 5 | Wedge Seat Ring* | Bronze C83600 / CuSn5Zn5Pb5 – or Integral Cast Iron |
| 6 | Stem | AISI 420 (13Cr) stainless steel / Brass C46400 |
| 7 | Stem Nut (Internal) | Brass / Bronze (high strength) |
| 8 | Packing | PTFE + graphite / Pure flexible graphite |
| 9 | Bonnet Gasket | Compressed fibre (non‑asbestos) or graphite |
| 10 | Gland | Cast Iron |
| 11 | Handwheel | Cast Iron / Ductile Iron / Pressed Steel |
| 12 | Bolting | Steel Gr. 8.8, zinc plated (option: SS304/316) |
Standard metal seated construction utilises integral cast iron seats machined directly into the body and wedge. Bronze or stainless steel seat rings can be supplied as an option for improved wear resistance and anti‑galling properties.
5. PRESSURE – TEMPERATURE RATING (Cast Iron Body, PN16)
| Temperature (°C) | Max. Working Pressure (bar) |
|---|---|
| -10 to 120 | 16.0 |
| 150 | 13.5 |
| 200 | 11.0 |
| 250 | 9.0 (special packing and seat consultation required) |
Cast iron is not recommended for continuous service above 200 °C. For temperatures below -10 °C, use ductile iron or steel valves. Ratings are based on EN 1092-1 non‑shock conditions.
6. DIMENSIONS & WEIGHTS (EN 558‑1 Series 8, PN16 Flanged)
| Nominal Size DN | Face‑to‑Face L (mm) | Height (Closed) H (mm) | Handwheel Dia. (mm) | Approx. Weight (kg) |
|---|---|---|---|---|
| 50 | 178 | 290 | 200 | 17 |
| 80 | 203 | 360 | 250 | 29 |
| 100 | 229 | 430 | 300 | 42 |
| 150 | 267 | 570 | 355 | 75 |
| 200 | 292 | 700 | 400 (gear) | 135 |
| 250 | 330 | 830 | 500 (gear) | 220 |
| 300 | 356 | 980 | 500 (gear) | 320 |
Handwheel operation is standard up to and including DN150. Bevel gear operator is recommended for DN200 and above to reduce operating torque. Dimensions may vary between manufacturers; refer to certified outline drawing for final values.
7. TESTING & INSPECTION
| Test Type | Test Medium | Test Pressure | Acceptance / Remarks |
|---|---|---|---|
| Shell Strength (Body) | Water | 1.5 × PN (e.g., 24 bar) | No visible leakage or deformation |
| Seat Closure (High Pressure) | Water | 1.1 × PN (e.g., 17.6 bar) | Per API 598 Rate C/D (metal seated) |
| Seat Closure (Low Pressure) | Air / N₂ | 6 ± 0.5 bar | Per API 598 (if specified by client) |
| Backseat Test (if applicable) | Water | 1.1 × PN | No leakage past stem |
Standard commercial test certificates are provided. EN 10204 3.1 material certificates, PMI, and NDE are available as optional extras.
8. AVAILABLE OPTIONS & ACCESSORIES
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Seat Ring Material: Bronze (standard replaceable), AISI 316 stainless steel, or weld‑overlay Stellite® for abrasive/corrosive media.
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Stem Upgrade: AISI 316 stainless steel, Monel®, or duplex stainless steel.
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By‑Pass Arrangement: Built‑in bypass on the valve body for high differential pressure opening.
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Position Indicator: Rising indicator rod attached to the stem for visual position verification.
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Locking Device: Lockable handwheel in fully open or closed position.
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Actuation: ISO 5210 mounting pad for electric or pneumatic actuators (with NRS stem adaptor).
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Coating: Standard epoxy painting (min. 250 µm DFT); optional two‑part epoxy or special coatings for buried service.
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Certifications: EN 10204 3.1, WRAS / ACS for potable water, PED 2014/68/EU, ATEX (with actuator).
9. ORDERING INFORMATION
When requesting a quotation, please specify the following:
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Valve type: NRS Cast Iron Gate Valve, Metal Seated
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Nominal size: DN _____
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Pressure class: PN10 / PN16
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Body material: Cast Iron (ASTM A126 B / EN‑GJL‑250)
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Seat material: Integral cast iron / Bronze / Stainless steel (select)
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Stem material: Stainless steel 420 / Brass / 316 (select)
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Medium, operating pressure and temperature
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Connection: Flanged EN 1092‑1
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Gear operator required? (Yes / No)
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Additional requirements: (bypass, locking device, special coating, certificates, etc.)
This data sheet represents general industrial practice for cast iron NRS metal seated gate valves. The manufacturer should be consulted for detailed engineering drawings and guaranteed performance data for your specific service conditions.
