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Fan Encyclopedia

2021-07-16 200
Fan Encyclopedia

Ventilator selection method and ordering requirements

The use environment should be considered before selection:
Where is the fan installed? (Is it indoor or outdoor, is it adjacent to an office, commercial or residential building, installed on the ground or hoisted on the floor?)
If it is installed outdoors, what are the surrounding environmental conditions?
What are the restrictions on existing venues? Is there enough space for future maintenance and removal of parts?
Are there restrictions on the weight, power capacity, noise or vibration of the facility?
In order to achieve the effect, what is the type of fan installation?
What are the requirements for power costs and auxiliary functions?

Principles of fan selection:
The application environment and purpose of the fan must be considered before the model selection, and the model selection of the product can be made after the establishment.
When ordering the fan products of our company, the user should clearly specify the name, model, power, speed, rotation direction and quantity of the fan to be ordered.
When ordering a centrifugal fan, it is necessary to indicate the transmission mode, rotation direction, outlet angle, and whether it is equipped with a shock absorber
and a shock-absorbing frame (generally A, C, and D types should be included);
If the two machine numbers can meet the requirements in the same fan type, please select the smaller machine number.
When the machine number is greater than or equal to 7.5kw, a step-down starting device must be installed during power distribution.
After the fan is connected to the pipeline, the noise is reduced by about 5-10db.
When choosing ventilation, try to avoid the use of ventilators in series or parallel operation. When it is unavoidable, ventilators of the same model and performance should be
selected to work together; when series connection is used, the first-stage ventilator to the second-stage ventilation There must be a certain distance pipeline connection between the machines.
The company has been committed to product improvement and optimization. Product specifications and parameter sizes in the sample are subject to change without notice.

The angle position diagram of the air outlet of the A type fan:

Angle position diagram of air outlet of C-type fan:

Statement: The product manufacturing standards are implemented in accordance with the performance parameters, installation dimensions, and structure types of the latest samples. If you have other requirements, please specify when ordering

Fan instructions:

(1) Special precautions
The grounding of the fan shell or motor shell must be reliable, and it is forbidden to run with over-rated current and run without phase.

(2) Receiving inspection and preparation for fan installation
1、Before unpacking the fan, check whether the package is intact, whether the fan nameplate parameters meet the requirements, and whether the accompanying accessories are complete and complete.
2、Carefully check whether the fan is deformed or damaged during transportation, whether the fasteners are loose or fall off, whether the impeller is rubbed, and check all parts of the fan. If an abnormal phenomenon is found, it should be used after repair.
3、Prepare all kinds of materials, tools and sites required for fan installation.

(3) Fan installation
Before installation:check all parts of the fan thoroughly, whether the machine is complete, whether the rotation direction of the impeller and the casing is the same, whether the connection of each part is tight, whether the main components such as the impeller, main shaft, bearing, and casing are damaged, and whether the transmission group is flexible Wait.
When installing:pay attention to check the case, there should be no tools or sundries that have fallen in or left behind. In order to prevent rust and reduce the difficulty of disassembly, some joint surfaces should be coated with a layer of grease or mechanical oil. When connecting the fan to the foundation joint surface and the air inlet and outlet pipes, they should be adjusted so that they are naturally consistent. Do not connect forcibly. Do not add the weight of the pipe to the fan. Pay attention to ensuring the horizontal position of the fan.

Fan operating instructions:

In order to prevent the motor from being burnt due to overload, when the fan is started, it must be carried out without load (close the valve on the inlet side and open the valve on the outlet side slightly). If the condition is good, open the valves one by one until the specified working conditions. The current should be strictly controlled during operation. Must not exceed the rated value.

1、The following preparations should be made before starting the fan: A close the inlet valve and open the outlet valve slightly; B check the gap size of each part of the fan, whether the rotating part and the fixed part collide.
2、After the fan is started, when it reaches the normal speed, check whether the bearing temperature is normal during operation. When the bearing temperature has no special requirements, the temperature rise of the bearing shall not exceed the ambient temperature of 40℃; the root mean square vibration of the bearing part The speed value should not be greater than 4.6mm/s. If the fan is found to have violent vibration, impact, or the bearing temperature rises rapidly, it should be stopped urgently.
3、In use, excessive or insufficient flow often occurs. There are many reasons for this phenomenon. If such a scene occurs during use, it is mainly caused by the large or small resistance in the main pipe network, or the fan working in the non-moving area. If it is in use, it gradually decreases after a long time, or suddenly decreases in a short time, mainly due to the blockage of the pipe network.

After the fan is installed, the flow rate is too low or insufficient during the formal operation. The main reasons are as follows:

1、The actual value of pipe network resistance differs too much from the calculated value. From the general pipe network characteristic equation: P=KQ2, it can be seen that if the actual value is less than the calculated value, the flow will increase; if the actual value is greater than the calculated value, the flow will decrease.
2、When the selection does not consider the influence of the total pressure deviation AP of the fan itself, the flow will increase: when the deviation is negative, the flow will decrease.

Precautions for fan maintenance work:

1、The fan must be used by a dedicated person, repaired by a dedicated person, and not allowed to run with illness.
2、Please check whether the installation foundation is good, whether the motor wiring is correct, whether the electrical system meets the specifications, and ensure the normal operation of the fan;
3、If the fan equipment is started after inspection, you must pay attention to whether the components of the fan are normal;
4、Regularly remove the dust inside the fan, especially the dust, dirt and other impurities on the impeller to prevent rust and unbalance.
5、In order to ensure personal safety, the maintenance of the fan must be carried out during shutdown;
6、The power supply must be cut off before maintenance or disassembly of the fan to avoid accidents. When the fan has a serious failure (brush vibration/spindle and blade deformation/bearing burnt out), non-professionals are not allowed to disassemble the fan to avoid danger.


Precautions during normal operation of the fan:


1、During the start, stop or operation of the fan, if an abnormal condition is found, it should be checked immediately. If it is a minor fault, the cause should be found out in time and try to eliminate it. If a major fault is found, the maintenance should be stopped immediately.
2、In addition to replacing the lubricant after each overhaul, the lubricant should also be replaced according to the actual situation under normal circumstances.

Precautions for fan maintenance work:

1. The bearing box vibrates severely
① The fan shaft is not concentric with the motor shaft, and the coupling is installed crookedly
② Friction between the casing or the air inlet and the impeller
③ The rigidity of the foundation is not firm
④ The impeller rivet is loose or the impeller is deformed
⑤ The impeller shaft and the shaft are loose, or the coupling bolts are loose
⑥ The connecting bolts of the casing and the bracket, the bearing box and the bracket, the bearing box cover and the seat are loose
⑦ Poor installation of fan inlet and outlet pipes
⑧ The rotor is unbalanced and the induced draft fan blades are wornan examination.

2. The bearing temperature rise is too high
① The bearing box vibrates violently
② The quality of lubricating grease is not bright, deteriorated, contains too much dust, sticky sand, dirt and other impurities
③ The tightening force of the connecting bolts of the bearing box cover and seat is too large or too small
④ The installation of the shaft and the rolling bearing is skewed, and the front and rear bearings are not concentric
⑤ The rolling bearing is damaged Third, the electrode current is too large or the temperature rise is too high
3. Electrode current is too large or temperature rise is too high
① The intake pipe gate or throttle valve is not closed tightly when driving
② The flow exceeds the specified value
③ The density of the air conveyed by the fan is too high or there are viscous substances
④ The input voltage of the motor is too low or the single-phase power is cut off
⑤ The coupling is not connected properly, the apron is too tight or the gap is uneven
⑥ Affected by severe vibration of the bearing housing


Daily maintenance and maintenance of the fan:


1. The fan blades should be cleaned regularly to extend the service life of the fan;
2. The elasticity of the belt should be adjusted regularly;
3. The air inlet of the fan should be kept unobstructed;
4. The air outlet must ensure that the shutter opening is greater than 70%;
5. The continuous use time can run for a long time;
6. It is best to use a magnetic control button switch for the fan switch to prevent the motor from being burnt due to poor contact;
7. The fan motor should be waterproof and kept clean.