The manufacturer of small power frequency centrifugal fan introduces the precautions for fan use

With the development of the times, the process of industrialization is moving towards a more far-reaching place. With the upgrading of the industrial sector, the mode of production has also been constantly evolving. Industrial machinery is one of them. Fans play an important role in it. Next, the manufacturer of small power frequency centrifugal fans will introduce the precautions for fan use.
Shutdown procedure
1. Emergency shutdown: in case of one of the following conditions during unit commissioning, emergency shutdown shall be carried out immediately. The operation of emergency stop is to press the main motor stop button, and then carry out the aftercare after the shutdown.
A. The centrifugal fan suddenly vibrates strongly and has exceeded the trip value.
B. There is scratch or abnormal friction sound inside the body.
C. There is smoke at any bearing or seal, or the temperature of a bearing rises sharply to the alarm value.
D. When the oil pressure is lower than the alarm value and cannot return to normal.
E. The liquid level of the oil tank is low and there is suction.
F. The shaft displacement value increases continuously and reaches the alarm value.
2. Normal shutdown: the normal shutdown of the unit shall be operated according to the following procedures.
A. Gradually open the vent valve (or outlet bypass valve) and gradually close the vent valve.
B. Gradually close the air inlet throttle valve to 20~25 °.
C. Press the stop button and pay attention to whether there is any abnormality during the shutdown.
D. The oil supply can be stopped after the unit stops for 5 to 10 minutes, or when the bearing temperature drops below 45 ℃. For the unit with floating ring seal, the seal oil pump must continue to supply oil until the body temperature is lower than 80 ℃.
After the unit is stopped, rotate the rotor 180 ° regularly within 2-4 hours.
Installation matters
1. The installation of the integral unit of the centrifugal fan shall be directly placed on the foundation and leveled with a pair of inclined sizing blocks.
2. For centrifugal fans assembled on site, the cutting surface on the base shall be properly protected from rust or operation. When the base is placed on the foundation, it shall be leveled with a pair of inclined sizing blocks.
3. The bearing seat and the base shall be closely connected, and the longitudinal non-levelness shall not exceed 0.2/1000. The horizontal non-levelness shall not exceed 0.3/1000 on the main shaft with a level gauge, and the horizontal non-levelness shall not exceed 0.3/1000. The level gauge shall be used to measure on the horizontal split of the bearing seat.
4. Before grinding and scraping the bearing bush, the rotor shaft centerline and the casing shaft centerline shall be corrected, and the clearance between the impeller and the air inlet and the clearance between the main shaft and the shaft hole on the rear side of the casing shall be adjusted to make it conform to the provisions of the technical documents of the equipment.
5. When the main shaft and bearing bush are assembled, they shall be inspected according to the provisions of the technical documents of the equipment. The interference between the bearing cover and the bearing shell shall be 0.03~0.04 mm (measure the outer diameter of the bearing shell and the inner diameter of the bearing seat).
6. When assembling the fan casing, the position of the casing shall be aligned with the rotor axis as the reference, and the axial and radial clearance between the impeller air inlet and the casing air inlet shall be high-speed to the range specified in the technical documents of the equipment, and the anchor bolts shall be checked for tightness. If the clearance value is not specified in the technical documents of the equipment, the general axial clearance should be 1/100 of the outer diameter of the impeller, and the radial clearance should be evenly distributed, and its value should be 1.5/1000~3/1000 of the outer diameter of the impeller (the larger one is the smaller one). When adjusting, try to make the clearance smaller to improve the fan efficiency.
7. When aligning the fan, the different axial degrees of the fan shaft and the motor shaft: the radial positioning displacement shall not exceed 0.05 mm, and the inclination shall not exceed 0.2/1000.
8. For the centrifugal fan equipped with rolling bearing, the different axial degrees of bearing holes on the two bearing frames can be subject to flexible rotation after the rotor is installed.
Commissioning method
Centrifugal fan is a complex equipment, mainly composed of air inlet, air valve, impeller, motor and air outlet. The effect of centrifugal fan is different under different conditions. Therefore, the operation conditions of different parts are not uniform, and the effect of centrifugal fans will be affected. Commissioning the centrifugal fan to the best state can be started from many aspects.
1. The centrifugal fan is allowed to be started at full voltage or reduced voltage, but it should be noted that the current at full voltage starting is about 5-7 times the rated current, and the reduced voltage starting torque is proportional to the square of the voltage. When the grid capacity is insufficient, the reduced voltage starting should be used.
2. When commissioning the centrifugal fan, carefully read the product manual and check whether the wiring method is consistent with the wiring diagram; Carefully check whether the working voltage of the power supply to the fan meets the requirements, whether the power supply is out of phase or in phase, and whether the capacity of the equipped electrical components meets the requirements.
3. During the test run, the number of people shall not be less than two. One person shall control the power supply, and the other person shall observe the operation of the fan. In case of any abnormality, stop the machine immediately for inspection; First, check whether the rotation direction is correct; After the centrifugal fan starts to operate, immediately check whether the operating current of each phase is balanced and whether the current exceeds the rated current; If there is any abnormal phenomenon, stop the machine for inspection. After five minutes of operation, stop the machine to check whether there is any abnormality in the fan, and start the machine again after confirming that there is no abnormality.
4. During the test run of the two-speed centrifugal fan, start the low speed first and check whether the rotation direction is correct; When starting at high speed, the fan must be stopped before starting to prevent the switch from tripping and motor damage due to reverse rotation at high speed.
5. When the centrifugal fan reaches the normal speed, measure whether the input current of the fan is normal. The operating current of the centrifugal fan cannot exceed its rated current. If the operating current exceeds its rated current, check whether the supplied voltage is normal.
6. The motor power required by centrifugal fan refers to the larger power required for centrifugal fan and fan case when the air inlet is fully open under certain conditions. If the air inlet is fully opened for operation, the motor may be damaged. It is better to close the valve on the inlet or outlet pipe of the fan during the fan commissioning, and gradually open the valve after operation until the required working condition is reached, and pay attention to whether the operating current of the fan exceeds the rated current.
The efficiency of the centrifugal fan can reach more than 98% by strictly following the above commissioning methods.
To sum up, after we understand the precautions for the use of fans, we can make more detailed selection of fans with more sufficient base gas. On the premise of meeting the basic needs of industrial production, the fans produced by small power frequency centrifugal fan manufacturers are also constantly developing new technologies and products in line with the trend of the times. The future development prospects are very good.