Full Set Fertilizer Granulation Equipment – 6-7 Tons/Hour Production Line

Full Set Fertilizer Granulation Equipment – 6-7 Tons/Hour Production Line

Induced Draft Fan

Instruction Manual

Qingdao BLS Engineering & Machinery Co., Ltd

I. Application

4-72 type induced draft fan is used for indoor ventilation and air exchange in factories and large buildings. It is suitable for delivering air and non-self-igniting, non-toxic, and non-corrosive gases. The gas should not contain sticky substances, and dust/hard particles must not exceed 150mg/m³. Maximum gas temperature: 80°C.

II. Type

Based on the motor side view:

• Clockwise rotation → Right rotating I.D. Fan
• Counterclockwise rotation → Left rotating I.D. Fan

Outlet position: adjustable from 0° to 225°, at 45° intervals (for NO. 8~12 fans).
Transmission modes: A, B, C, and D.

• NO. 2.8~6: A-type
• NO. 8~12: C or D-type
• NO. 16~20: B-type

III. Structure

1. Impeller: 10 backward curved blades; balanced; made of steel or cast aluminum.
2. Machine Shell:
   • NO. 2.8~12: One-piece, non-detachable.
   • NO. 16~20: Three-piece type (horizontal and vertical split).
3. Air Inlet: Integrated with a curved axial section to reduce loss.
4. Transmission Parts: Include shaft, bearing box, rolling bearing, belt pulley, and coupling.

IV. Flow Adjustment

Adjust flow by:

1. Using a throttling device.
2. Changing fan speed (only if belt-driven).
3. Replacing the fan with a different pressure rating.
4. Modifying pipe network resistance.

Note: Direct or coupling-connected fans cannot change speed. Belt-driven fans can by changing pulley diameter. Never exceed max rated speed. Always control flow with throttling or pipeline resistance adjustments for efficiency and safety.

V. Installation and Operation

Before installation:

• Prepare tools and materials.
• Check impeller, bearings, spindle; clean bearing box with kerosene if needed.

Installation Requirements

1. Do not let ventilation pipe weight affect the fan shell. Keep shaft level.
2. Use bolts for air inlet connection; tighten with three-head screws.
3. Adjust outlet angle by rotating rear disk; ensure level flange (NO. 8~12).
4. For NO. 8~12D: Use dial gauge and feeler for coaxiality (tolerance: 0.05mm axial, 0.1mm face).
5. Ensure no friction or tightness before starting; rotate rotor by hand.
6. Install pulley or sprocket guard after motor. Use protective net if no inlet pipe is attached.

Startup Caution

Motor power is based on a specific load. If running without resistance, there’s a risk of burnout. Always:

• Start with valves closed
• Gradually open after operation begins
• Monitor current to avoid overload

VI. Maintenance

1. Fan Maintenance System

• Only operate when in normal condition.
• Verify all parts after maintenance.
• Clean dust and prevent rust regularly.
• Do not service during operation.

2. Operation Checks

• Adjust flow via throttling if needed.
• Check thermometer and oil mark regularly.
• Investigate any unusual behavior immediately.
• Fix small faults promptly; stop operation for major issues.
• Change lubricant after each overhaul and on schedule.

3. Common Faults and Causes

1) Bearing Box Vibration

• Misalignment of shafts or coupling
• Rubbing of impeller with shell
• Weak or loose foundation
• Loose impeller or deformed wheel disc
• Loose bolts or connections
• Unbalanced rotor or narrow pipes with high speed

2) Bearing Overheating

• Vibration
• Impure or old lubricating oil
• Incorrect bearing tension
• Misaligned bearings
• Damaged bearing

3) High Motor Current or Temperature

• Valve not closed at startup
• Excess flow or air leakage
• High air density increases pressure
• Low voltage or phase loss
• Poor coupling or over-tight belt

4) Belt Issues

• Belt slides down: pulleys misaligned
• Belt moves up/down: pulleys too close or belt too long

VII. Image Reference

Shell of I.D. Fan + Triangle Belt + Belt Pulley for Motor + Slideway for Motor