I. Main Types of Cast Iron Valves
- Gate Valve
- Features: Full open/full close, low fluid resistance, suitable for medium cutoff.
- Structure: Rising stem (e.g., Z45X-16Q), non-rising stem.
- Applications: Water supply, drainage, sewage treatment.
- Globe Valve
- Features: Flow regulation, good sealing, but higher flow resistance.
- Structure: Straight-through, angle-type (e.g., J41H-16C).
- Applications: Chemical, petroleum pipelines.
- Butterfly Valve
- Features: Compact size, flexible operation, suitable for large-diameter pipelines.
- Structure: Centerline type, double eccentric (e.g., D71X-16Q).
- Applications: Fire protection systems, HVAC.
- Check Valve
- Features: Automatically prevents backflow.
- Types: Swing type, lift type (e.g., H44X-10Q).
- Applications: Pump outlets, water supply systems.
- Ball Valve
- Features: 90° rotation for rapid on/off control.
- Material: Floating ball, fixed ball (e.g., Q41F-16C).
- Applications: Chemical, food processing industries.
II. Cast Iron Material Classifications
- Gray Cast Iron (HT200/HT250)
- Characteristics: Low cost, wear-resistant, but brittle.
- Applications: Low-pressure, ambient-temperature environments (e.g., water supply).
- Ductile Iron (QT450-10)
- Characteristics: High strength, good toughness, can replace steel valves.
- Applications: Medium-high pressure, high-temperature environments (e.g., chemical, fire protection).
III. Technical Parameters
- Pressure Ratings
- ISO: PN6/PN10/PN16/PN25 (equivalent to Class 150/300, etc.).
- ANSI: Class 150/300/600.
- Nominal Diameter (DN)
- DN50–DN600 (large diameters common in municipal projects).
- Temperature Range
- Gray cast iron: -10°C to 120°C; Ductile iron: -30°C to 200°C.
- Connection Types
- Flange (most common), threaded, wafer, welded.
IV. Typical Applications
- Water Supply & Drainage
- Gate valves, butterfly valves for water plants and pump stations.
- HVAC Systems
- Butterfly valves, check valves for chilled water loops.
- Chemical/Petroleum
- Globe valves, ball valves for corrosive media transport.
- Fire Protection
- Butterfly valves, signal butterfly valves for pipeline control.
V. Valve Selection Guidelines
- Medium Properties
- Corrosive media: Ductile iron with epoxy coating; particulate media: wear-resistant gate valves.
- Pressure & Temperature
- High-pressure/high-temperature environments: Prefer ductile iron to avoid brittleness of gray cast iron.
- Installation Space
- Large-diameter pipelines: Butterfly valves; space-constrained areas: Globe valves.
- Environmental Factors
- Humid environments: Consider anti-corrosion (e.g., galvanized coating).
- Humid environments: Consider anti-corrosion (e.g., galvanized coating).
