Whether the manufacturer of negative pressure fan has legal business qualification approved by the state, such as business license, tax registration certificate, organization code certificate, production and business license, etc.

Second, look at the brand awareness and user reputation of negative pressure fans:

1. The brand awareness and user reputation of general negative pressure fans can only be created by combining the high-quality product quality of manufacturers with long-term and perfect advertising. It needs a certain market accumulation and user experience, not overnight. The product quality of a negative pressure fan with high brand awareness and good user reputation is definitely more reliable than that without a brand.

2. The brand awareness can be inquired by the national intellectual property management department, and the brand can be understood from TV, newspapers, quality and technical supervision departments, networks, media and industry associations. The word-of-mouth of users can be understood through their customer cases and used friends.

Third, look at product quality certification:

Judging the quality by looking at the quality certification of negative pressure fans, negative pressure fan products must have "CCC" logo and energy efficiency logo, and can also be identified by looking at quality management certification, environmental protection and energy-saving factory inspection certificate, product instruction manual and warranty card, especially negative pressure fan products without this "CCC" certification logo are not allowed to be sold in the market.

Fourth, look at the manufacturing process and materials of negative pressure fan:

1, manufacturing process: By looking at the manufacturing process details of the negative pressure fan, such as the tightness of the joints of the outer frame, the smoothness of the blades, the anti-slip degree of the fastening screws, etc. These details can reflect the manufacturing technology level and attitude of negative pressure fan manufacturers.

2. Look at the motor: the core component of the negative pressure fan is the motor. The quality of motor directly determines the ventilation and cooling effect, service life and circuit safety of negative pressure fan. High-quality motors will indicate the manufacturer's name, power, motor grade, power, current, voltage, speed, protection grade, energy efficiency label and other important parameters on the motor nameplate.

3. Look at the frame. The outer frame of high-quality negative pressure fan is thick and smooth, and it is not easy to deform. We can knock with our hands when we buy it. Press the outer frame of the negative pressure fan to see if the surface is uneven and deformed.

Extended data:

Use environment of negative pressure fan

1, the use environment should always be kept clean, the surface of the fan should be kept clean, and there should be no sundries in the air inlet and outlet. Regularly remove dust and other sundries from fans and pipes.

2. Only when the fan is completely normal can it be operated. At the same time, it is necessary to keep the power supply facilities with sufficient capacity and stable voltage, and it is strictly forbidden to run without phase. Power supply lines must be dedicated lines, and temporary lines shall not be used for power supply for a long time.

3. During the operation, it is found that the fan has abnormal sound, the motor has serious fever, the shell is charged, the switch trips, and it cannot be started. Stop the machine immediately for inspection. In order to ensure safety, maintenance is not allowed in the operation of the fan. After maintenance, it should be put into trial operation for about five minutes, and then it should be turned on after it is confirmed that there is no abnormal phenomenon.

4. According to the service environment, the bearing grease shall be replenished or replaced from time to time (it is not necessary to replace the grease for the motor closed bearing during the service life). In order to ensure good lubrication when the fan is running, the oiling frequency should be no less than 1000 hours/time, and ZL-3 lithium-based grease should be filled in two-thirds of the inner and outer rings of closed bearings and motor bearings. Oil-free operation is prohibited.

5, the fan should be stored in a dry environment, to avoid the motor be affected with damp. When the fan is stored in the open air, rainproof measures should be taken. During storage and handling, the fan should be prevented from being hit, so as not to damage the fan.

Baidu encyclopedia-negative pressure fan