Knowledge! The difference between negative pressure fan and axial flow fan

The cylindrical axial flow fan is the type of fan that we often see installed on the wall, has a cylindrical shape, and makes relatively loud noise when rotating. Both can be used in factory ventilation. What is the difference between negative pressure fans and cylindrical shaft fans?

Negative pressure fans are mainly used for strong ventilation, exhausting smoke, odors, and dust to solve the problem of poor ventilation. There are currently two types of negative pressure fans on the market, one is a belt-type negative pressure fan, and the other is a direct-drive negative pressure fan. Pressure blower, in order to reduce the trouble of maintenance and replacement of belts during use, a direct-drive negative pressure blower was developed and manufactured. Most of the common FRP anti-corrosion negative pressure blowers are direct-drive negative pressure blowers, which are generally widely used. In places with corrosive gases such as electroplating, chemical industry, etching, etc., it is mainly used to solve the problems of poor ventilation such as high temperature and heat, smoke and odor, dust and dust in these harsh environments. The belt is not corrosion-resistant, so the use environment is fully taken into consideration during R&D and design. The particularity is that anti-corrosion fiberglass materials are used in the material selection. The fan frame and fan blades are all made of fiberglass. The shutters are made of PVC. The motor uses high-quality pure copper wire direct-drive energy-saving motors. The protective net is anti-corrosion sprayed. Belt-type negative pressure fans are mainly based on cost savings and cost considerations. Generally, economical and affordable ordinary negative pressure fans are belt-type. For example, the square negative-pressure fans we often see made of galvanized sheets are belt-type. There is a big difference between the motor quality of the direct-drive negative pressure fan and the motor quality of the belt-type negative pressure fan. For negative pressure fans with the same specifications and air volume, the cost of the direct-drive negative pressure fan motor is higher than that of the belt-type negative pressure fan motor. It is much more expensive. In appearance, the direct-drive negative pressure fan motor is much larger than the belt-type negative pressure fan motor. Generally, the direct-drive negative pressure fan motor will use level 10 or above, while the belt-type negative pressure fan motor will be level 4. This is because the motor of the direct-drive negative pressure fan starts to directly drive the fan blades to start drawing air. The torque required is very large. The 4-level motor of the belt-type negative pressure fan cannot reach this torque at all. The motor of the belt-type negative pressure fan is a 4-level high-speed motor. The motor must be equipped with a small pulley to reduce the speed of the fan blade driven by the motor, otherwise it cannot meet the large air volume load of the fan blade.

The air volume of the belt-type negative pressure fan is generally smaller than that of the direct-drive negative pressure fan. During use, due to the thermal expansion, contraction and wear of the belt, the natural air volume of the belt-type negative pressure fan will weaken. Because the direct-drive negative pressure fan has no belt, the air volume is almost constant during use. The difference between the direct-drive negative pressure fan and the belt-type negative pressure fan is also the issue of use and maintenance costs. During use, the direct-drive negative pressure fan requires almost no maintenance cost except for the labor cost of cleaning stains and dust, while the belt-type negative pressure fan requires almost no maintenance costs. Negative pressure fans need to frequently replace the belt during use. If the belt-type negative pressure fan is installed too high or on the roof, the maintenance cost of replacing the belt will be relatively high. Generally, the service life of belt-type negative pressure fans is shorter than that of direct-drive negative-pressure fans. If you have a certain economic affordability, it is recommended to choose direct-drive negative-pressure fans. For more details about negative pressure fan selection, please contact ZIBO DECENT MACHINERY CO.,LTD. directly.

Negative pressure fans are mainly used for ventilation and cooling, powerful exhaust and ventilation. At the same time, they can take away smoke, odor, dust and dust in the air during ventilation. They do not need to be connected to pipes and can be installed on the wall or window for direct use. , the exhaust volume is very large, reaching tens of thousands or hundreds of thousands of cubic meters per hour, and it is very energy-saving. A negative pressure fan with an exhaust volume of hundreds of thousands only consumes only 2-3 kilowatt hours of electricity per hour. Negative pressure fans usually They are all equipped with dust-proof and rain-proof blinds, which can effectively prevent dust and rain when they stop working. The negative pressure fan is suitable for overall ventilation and cooling of large-area workshops. Cylindrical axial flow fans are mainly used for local duct ventilation to exhaust smoke and odors. The air volume of axial flow fans is not very large. Generally, the air volume is in the range of several thousand. The volume is relatively small and the shape is cylindrical, making it easy to take over the duct. , has a certain wind pressure, suitable for local fixed-point duct exhaust in small areas, relatively high power, not particularly environmentally friendly and energy-saving, and does not have blinds. Generally, negative pressure fans are used for overall ventilation and cooling of the factory. If it is a local duct to extract smoke and odor , just use an axial flow fan.