This article's table of contents introduction:
- The Materials & Types
- The Model Numbers (4-73, 5-48, 6-51, 9-19)
- The Blades (Crucial for Tunnel Applications)
- Common Configurations for Tunnel Ventilation
- Are you looking for:
It appears you are listing key specifications for Centrifugal Fans (specifically Induced Draft - ID and Forced Draft - FD fans) used in industrial applications such as tunnels, power plants, or cement plants.
Here is a breakdown of what these terms mean and how they relate to tunnel ventilation or heavy industrial air movement.
The Materials & Types
- Carbon Steel: This is the standard material for the fan housing and blades. It offers high strength and durability for handling large volumes of air or gas at moderate temperatures (typically up to 400°C / 750°F). For tunnel applications, carbon steel is common unless corrosive gases or very high temperatures are present.
- ID Fan (Induced Draft): Pulls air through a system (e.g., drawing exhaust out of a tunnel or furnace). The fan operates under negative pressure.
- FD Fan (Forced Draft): Pushes air into a system (e.g., supplying fresh air to a tunnel or combustion air to a boiler). The fan operates under positive pressure.
The Model Numbers (4-73, 5-48, 6-51, 9-19)
These model numbers refer to Chinese / Industrial Standards (JB/T or similar) for centrifugal fan design parameters. They describe the blade type and pressure characteristics.
-
First Digit (Type / Pressure Coefficient):
- 4-73 & 9-19: High Pressure fans. 9-19 is a very high pressure fan typically used for small flow, high resistance systems (e.g., pneumatic conveying or high-resistance tunnel booster fans). 4-73 is a medium-high pressure fan.
- 5-48 & 6-51: Medium Pressure fans. These are the most common types for general tunnel ventilation (both supply and exhaust).
-
Second Digits (Specific Speed): The number indicates the specific speed of the impeller. Higher numbers generally mean higher flow and lower pressure.
- 73 & 51: High flow, relatively lower pressure (very common for tunnel longitudinal ventilation).
- 48: Medium flow, medium pressure.
- 19: Very low flow, very high pressure.
The Blades (Crucial for Tunnel Applications)
The "Blades" in this context are typically Backward-Curved (or Backward-Inclined).
- Why this matters for Tunnels:
- Non-Overloading Power: Unlike forward-curved blades, backward-curved blades ensure the motor won't burn out if the duct system is partially blocked (a common safety risk in tunnels during construction).
- High Efficiency: They are more efficient for the high flow rates required in tunnel ventilation (moving large volumes of air).
- Self-Cleaning: The blade shape allows dust and debris to pass through more easily than other designs.
Common Configurations for Tunnel Ventilation
Based on your list, the most logical application is a set of fans for a highway, railway, or mining tunnel:
| Fan Type | Model | Role in Tunnel | Characteristic |
|---|---|---|---|
| FD Fan | 4-73 or 6-51 | Supply Air (Push fresh air in or drive longitudinal flow) | High flow, medium pressure. Efficient for moving large volumes. |
| ID Fan | 5-48 or 9-19 | Exhaust Air (Pull out smoke/dust during construction or emergency) | 5-48 for normal exhaust. 9-19 for Jet Fan type high pressure booster units. |
Are you looking for:
- Replacement Blades / Impellers: For an existing fan in a tunnel system?
- A complete Fan Unit: For a new tunnel ventilation project?
- Spare Parts: Specifically backwards-curved carbon steel blades (single or double arc)?
To provide a more accurate answer, please clarify:
- Purpose: Is this for a mining tunnel, a road/rail tunnel, or a construction tunnel?
- Requirement: Do you need a complete fan assembly, or just the impeller (wheel with blades) as a spare part?
- Specifics: Do you know the size (e.g., No. 10, No. 16, No. 20) of the fan? (e.g., 4-73 No. 16D).
