This article's table of contents introduction:
- Interpretation of Your Specification
- Suitable Fan Type
- Explosion-Proof Requirements
- Technical Specifications (Typical for your query)
- How to Select the Correct Fan
- Potential Manufacturers / Model Numbers (for reference)
- Critical Warning: Explosion Proof Certification
Based on the keywords you’ve provided, it appears you are looking for a High-Temperature, Explosion-Proof Induced Draft Fan (Boiler Fan) designed for a roaster application, specifically requiring a pressure of 2960 Pa.
Here is a breakdown of what that specification means, the likely application, and key selection criteria for purchasing such a fan.
Interpretation of Your Specification
- Roaster: The fan is likely used in industrial food processing (coffee, nuts, cocoa), mineral processing, or chemical roasters.
- High Temperature: The gas medium being moved is hot (typically 150°C to 350°C or higher).
- Blast (or Induced Draft): "Blast" often refers to Forced Draft (pushing air into the furnace), but in roasters, it can also mean Induced Draft (sucking hot flue gas out). With 2960 Pa, this is a medium pressure fan.
- 2960 Pa: This is the total pressure requirement (approx. 300 mmAq or 11.8 inches WC). This is a standard specification for a Roaster ID fan.
- Explosion Proof: The motor and possibly the fan housing are designed to contain sparks or prevent ignition in an explosive atmosphere (e.g., grain dust, coal dust, combustible gases).
Suitable Fan Type
Given the high temperature and explosion-proof requirement, the most common configuration is:
- Type: Centrifugal (Radial) Fan
- Blade Design: Radial Blades (Paddle wheel) or Backward Inclined.
- Why: Radial blades are self-cleaning and handle particulate matter better. They are very robust for high temperature.
- Arrangement: Overhung (impeller overhung from the bearing housing) or Pedestal Mount (often necessary for temperatures >200°C to isolate bearings from heat).
Explosion-Proof Requirements
To confirm the fan is truly "Explosion Proof," it must meet specific standards. You must check for:
- Motor: Must be rated Ex d (Flameproof) or Ex e (Increased Safety) per ATEX (Europe) or Class I / Class II Div. 1 (USA). The motor fan cover must be non-sparking.
- Spark Arresting: The fan housing must be made of non-ferrous material (aluminum or stainless steel) OR the impeller must be made of a non-sparking material (aluminum bronze, stainless steel) and the housing lined.
- Shaft Seal: Must prevent hot gas leakage into the bearing housing or atmosphere.
- Grounding: The fan base must have a grounding point to dissipate static electricity.
Technical Specifications (Typical for your query)
Here is a likely technical data sheet for a fan matching your description:
| Parameter | Specification |
|---|---|
| Fan Type | Centrifugal, High-Temperature (W9-26 or similar series) |
| Air Volume (Capacity) | 2,000 – 15,000 m³/h (Select based on roaster size) |
| Total Pressure | 2960 Pa |
| Inlet Temperature | 150°C – 350°C (Max) |
| Medium | Hot air / Flue gas / Combustion gas |
| Explosion Proof Class | Ex d IIBT4 (Gas) or Ex tD A21 IP65 (Dust) |
| Material (Impeller) | 16MnR (carbon steel for <250°C) or Q345R / 304 Stainless Steel |
| Material (Housing) | Carbon steel (Q235) with refractory lining or Stainless Steel |
| Motor | Explosion-proof, IP55, F-grade insulation |
| Drive | Direct drive (D coupling) or Belt drive (C/pulley) |
| Cooling | Air cooling shaft or water-cooled bearing (for >200°C) |
How to Select the Correct Fan
Since "2960 Pa" is a specific pressure point, ensure the fan is not selected at the end of its performance curve.
Step 1: Calculate the actual system resistance. Is 2960 Pa the required static pressure or total pressure? If it’s total pressure, you need a fan that can deliver the required air volume at exactly that point.
Step 2: Check the temperature.
- Standard Fan: Air density at 20°C.
- High Temp Fan: Correct for air density at operating temperature.
- Example: Air at 200°C has a density roughly 60% lower than at 20°C.
- Rule: The fan motor for a 300°C application must be significantly larger than the motor for a 20°C application to move the same mass of air.
Step 3: Choose the right construction.
- For Roasters (Coffee/Nuts): Use Stainless Steel (304L) for hygiene and corrosion resistance due to acidic fumes.
- For Industrial/Boilers: Use Carbon Steel with a wear lining.
Potential Manufacturers / Model Numbers (for reference)
- China Model (Most common for this spec): Y9-35 or W8-29 series (High-temp, explosion-proof design).
- International Standards: Howden (D-series), Twin City (HP series), Chicago Blower (PF series).
Critical Warning: Explosion Proof Certification
Do not buy a "High Temperature" fan and assume it is Explosion Proof. You must request the ATEX Certificate (for Europe) or UL/CSA Listing (for North America) specifically stating the fan meets the gas group or dust group classification of your roaster environment.
- If you are roasting coffee/grains: The main risk is dust explosion (St class). You need a fan certified for Zone 20/21 (Dust).
- If you are roasting using natural gas/propane: The risk is gas leak explosion. You need a fan certified for Zone 1/2 (Gas).
Summary: You need a Centrifugal, High-Temperature (min 200°C), Explosion-Proof (Ex d or Ex tD), 2960 Pa Induced Draft Fan. Confirm the impeller material is non-sparking (aluminum or SS), and the motor has proper ATEX certification.
