Marble Saw Blade,Marble Cutting Disc,Marble Grinder Blade,Marble Cutting Blade Hubei Chengze Diamod Products Co., Ltd. , https://www.ryomaltools.com
Valves can be classified in various ways based on their function, structure, driving mechanism, pressure rating, temperature range, and material. This classification follows international and national standards to ensure consistency and clarity in valve selection and application.
**1. General Classification**
Valves are categorized according to their function, design, and operating principles. Common types include gate valves, globe valves, throttle valves, instrument valves, plunger valves, diaphragm valves, plug valves, ball valves, butterfly valves, check valves, pressure-reducing valves, safety valves, steam traps, control valves, bottom valves, filtration equipment, and sewage valves.
**2. Classification by Driving Mode**
- **Automatic Valves**: These operate without external power, relying on the process medium to actuate them. Examples include safety valves, pressure relief valves, and steam traps.
- **Power-Driven Valves**: These use external energy sources such as electricity, compressed air, or hydraulic pressure. Electric valves, pneumatic valves, and hydraulic valves are common examples. Some combine multiple drive types, like gas-electric actuators.
- **Manual Valves**: Operated by hand using a wheel, handle, lever, or gear. For high-torque applications, gearboxes or worm gears may be used. Long-distance operation is possible with universal joints and transmission shafts.
**3. Classification by Function**
- **Shut-off Valves**: Used to open or close the flow of media. Examples: gate valves, globe valves, ball valves, butterfly valves, diaphragm valves, and plug valves.
- **Check Valves**: Prevent backflow in pipelines. Examples: swing check valves, lift check valves, and bottom valves.
- **Control Valves**: Regulate pressure, flow, or temperature. Examples: pressure-reducing valves, throttling valves, and control valves.
- **Safety Valves**: Protect systems from overpressure by releasing excess media. Examples: safety valves, relief valves, and emergency shut-off valves.
- **Special Purpose Valves**: Include steam traps, vent valves, drain valves, and others designed for specific functions.
**4. Classification by Nominal Pressure**
- **Vacuum Valves**: Operate at pressures below atmospheric.
- **Low-Pressure Valves**: PN ≤ 1.6 MPa.
- **Medium-Pressure Valves**: PN = 2.5–6.4 MPa.
- **High-Pressure Valves**: PN = 10–80 MPa.
- **Ultra-High-Pressure Valves**: PN ≥ 100 MPa.
**5. Classification by Operating Temperature**
- **Normal Temperature Valves**: T = 40°C to 120°C.
- **Medium-Temperature Valves**: T = 120°C to 450°C.
- **High-Temperature Valves**: T > 450°C.
- **Cryogenic Valves**: T = -100°C to 40°C.
- **Ultra-Cryogenic Valves**: T < -100°C.
**6. Classification by Nominal Diameter**
- **Small-Diameter Valves**: DN ≤ 40 mm.
- **Medium-Diameter Valves**: DN = 50–300 mm.
- **Large-Diameter Valves**: DN = 350–1200 mm.
- **Extra-Large-Diameter Valves**: DN ≥ 1400 mm.
**7. Classification by Structural Type**
- **Gate Valve**: The disc moves linearly along the seat axis.
- **Globe Valve**: The disc moves vertically to control flow.
- **Plug Valve**: The plug rotates around its centerline.
- **Ball Valve**: A spherical element rotates to open or close the flow.
- **Butterfly Valve**: The disc rotates around a central axis.
- **Sliding Valve**: The disc slides perpendicular to the flow direction.
**8. Classification by Connection Type**
- **Threaded Valves**: Connected via internal or external threads.
- **Flanged Valves**: Connected using flanges.
- **Welded Valves**: Joined by welding to the pipeline.
- **Clamp-Connected Valves**: Secured with clamps.
- **Sleeve-Type Valves**: Fastened with bolts that clamp the pipe ends to the valve.
**9. Classification by Body Material**
- **Metallic Valves**: Made from materials like cast iron, carbon steel, stainless steel, copper alloys, aluminum, titanium, and Monel.
- **Non-Metallic Valves**: Constructed from plastics, ceramics, glass, or enameled materials.
- **Lined Valves**: Metal bodies with internal linings (e.g., rubber or plastic) for corrosion resistance.
This comprehensive classification helps engineers and technicians select the most suitable valve for specific applications, ensuring safe, efficient, and reliable system performance.