Operation And Maintenance Instructions For General Centrifugal Fan

1、 Purpose

The general purpose centrifugal fan is suitable for conveying non flammable, explosive and non corrosive gases. The gas temperature is not more than 80 ℃, and the dust and hard particles contained in the gas are not more than 150mg/m3. It is widely used for general ventilation or local air supply and exhaust in industrial and mining enterprises, warehouses and other places; It is also used to smoke lampblack in the kitchens of hotels, guesthouses, canteens and restaurants; It can also be used as purification equipment, kitchenware equipment, HVAC units and other professional equipment.

2、 Installation

1. Before installation, carefully check whether the fan is damaged or deformed due to packaging and transportation. If yes, repair it properly before installation.

2. During installation, pay attention to check whether all connecting parts are loose. The clearance between rotating parts and adjacent parts shall be uniform without friction and collision, such as between impeller and air inlet and casing; Between belt pulley and belt cover.

3. No matter which installation method is adopted, the installation foundation shall have sufficient strength and stability. The fan must be firmly installed to avoid safety accidents caused by insecure installation.

4. The fan shall be generally installed on a suitable concrete foundation, and the fan foundation or base shall be firmly connected with the foundation with anchor bolts. For fans with small machine number and small motor power, they can also be fixed directly with flange screws.

5. When the fan is hoisted to the ceiling (under the floor), appropriate suspenders or hangers shall be used for installation. It should be noted that large fans cannot be hoisted.

6. It is better to use flexible flexible pipe to connect the fan and the pipe, and the weight of the pipe cannot be borne by the fan, which should be additionally supported appropriately.

7. Within the length range of twice the fan blade diameter at the inlet and outlet of the fan, sudden changes in elbows or other pipe sections should be avoided as far as possible, which will cause a sharp increase in pipe resistance and lead to abnormal fan performance.

8. During the electrical installation of the fan, the correct power supply must be connected according to the voltage, frequency and other information marked on the fan nameplate. The voltage fluctuation value shall not exceed ± 5% of the rated voltage.

9. The electrical wiring must be operated by professionals and correctly wired in strict accordance with the wiring diagram attached to the junction box to ensure safety.

10. For fans with motor power greater than 11KW, it is recommended to equip with speed reduction starting device.

3、 Use and maintenance

1. Before starting the fan, check whether there are any objects in the fan and pipe that hinder the rotation; Whether there are unsafe factors near the air inlet and outlet (such as objects that are easy to be inhaled or blown off), if any, they should be removed before starting.

2. Before officially using the fan, it is necessary to test the fan and confirm the following items: A. The wiring is correct. B. The fan has no abnormal sound. C. The power shall not be overloaded. D. The rotation direction and airflow direction of the fan are consistent.

3. If the rotation direction of the fan blade is inconsistent with that of the fan, the three-phase power supply needs to exchange the positions of the two-phase power lines of the motor at will before re commissioning. For single-phase power supply, it is required to change the wiring mode before re commissioning.

4. Most fans (such as 9-19, CF-11, 11-62, DF, etc.) are forbidden to run for a long time in the fully open state, that is, without connecting any inlet and outlet pipes. Otherwise, the motor will burn out due to overload operation of the motor. The short-term overload test should not exceed 3 minutes each time.

5. The machine can only be used formally after the test run is normal.

6. Do not start and stop the fan too frequently, otherwise the motor may be burnt out.

7. In case of abnormal noise or increased vibration during the operation of the fan, the fan shall be stopped for inspection immediately, and can be put into use again after the fault is eliminated. Abnormal noise and vibration are generally caused by the destruction of the dynamic balance of the fan blade, and the dynamic balance needs to be re calibrated.

8. In order to avoid damage to the fan caused by increased vibration due to damage to the dynamic balance of the impeller, the impeller shall be inspected at least once a month, and the dust and oil stains attached to the impeller shall be removed in time.

9. For the fan with oil drain hole on the fan housing, the oil accumulation and other liquids stored in the fan shall be removed regularly.

10. Check all parts of the fan regularly to ensure that the fan can be started at any time and operate normally.

11. When the fan is reused after being unused for a long time, check whether the connecting parts are firm and can be used normally only after the test run is normal.

12. When the fan is running, it is strictly forbidden to touch the impeller, main shaft, belt, pulley and other rotating parts to avoid personal injury.

13. Before regular inspection and maintenance, the fan must be shut down and the power must be cut off.

For belt driven fans (Type C, Type E), in addition to the use and maintenance according to the above, the following matters should also be noted:

1. After using the belt drive system for a period of time, the belt will become soft, and users need to tension the belt regularly.

2. The belt is a vulnerable part, and its wear degree should be checked regularly. If it is seriously worn, it should be replaced immediately. Generally, it is recommended to replace it once a year or so. It should be noted that the brand and specification of the new belt must be suitable, and the new and old belts cannot be mixed.

3. The belt shall not be stained with oil, or it may slip during operation.

4. Regularly check the belt pulley to ensure that it is firmly installed. If cracks or serious wear are found, replace it in time.

5. The bearing pedestal should be replenished with lubricating grease regularly, lithium based grease is generally recommended, and high-temperature grease is recommended when the temperature is high. In general environment, it is required to add grease every half a year. When the service environment is relatively harsh, the refueling cycle should be shortened. When using lampblack, it is recommended to refuel at least once a week. The filling amount of lubricating grease should be about 1/3 of the internal space volume of the bearing, and should not be too much or too little.

6. The bearing pedestal of the fan has been filled with enough lubricating grease when it leaves the factory, so it is unnecessary to add it before the fan is used for the first time.

4、 Common faults and cause analysis

Insufficient air volume:

1. The system pipe network has large leakage or foreign matter blockage.

2. The air inlet and outlet of the fan have large resistance or blockage.

3. The wind turbine rotates in the wrong direction. Or the impeller is unbalanced and vibrates.

4. The gas density is too high.

5. Motor speed fault, or belt slipping (if belt type) causes speed reduction.

Fan vibration:

1. Impeller is unbalanced

2. Friction of rotating parts

3. Pipe resonance

4. The foundation is not firm or the anchor bolt is loose

5. The spindle is bent, deformed or worn

6. The bearing is poorly installed or damaged

Motor overload:

1. The system resistance is small and the air volume is too large

2. The belt is too tight (such as belt type)

3. The motor power is too small

4. Excessive gas density

5. Poor insulation and motor fault

Abnormal noise of fan:

1. The bearing is damaged or impurities are mixed into the bearing

2. The spindle is bent, deformed or worn

3. Impeller collides with air inlet or casing

4. Poor design of pipeline system and excessive wind speed

5. Insufficient bearing lubrication

6. Shaft movement

7. Loose or damaged rotating parts of fan

8. The fan sucks foreign matters

Abnormal bearing temperature rise:

1. Too much or too little lubricating grease

2. Improper selection of lubricating grease or poor grease

3. The bearing is too tight

4. Bearing failure or fatigue wear