Purpose

The 4-72 centrifugal fan is mainly used for indoor ventilation and air exchange in general factories and large buildings, or for conveying air and other non-combustible, non-explosive, non-volatile gases that are harmless to the human body and non-corrosive to steel. The B4-72 centrifugal fan can exhaust flammable and volatile gases; the F4-72 centrifugal fan is mainly used for conveying corrosive gases. However, the gases conveyed by the 4-72, B4-72, and F4-72 centrifugal fans must not contain any viscous substances, and the content of dust and hard particles must not exceed 150mg/m³ ³ , and the gas temperature must not exceed 80℃.

The performance, optional parts, and base dimensions of the B4-72 fan are consistent with those of the 4-72 model, and can be selected according to its sample. The basic structure of this fan is the same as that of the 4-72 model. For 2.8A~6A, a B35 motor with flange and base is used; for N6~12C, D motors, the YB series corresponding to the Y series in the table is selected, and the installation type is B3.

The F4-72 centrifugal fan is made of stainless steel, fiberglass, or other corrosion-resistant materials, and its performance and base dimensions are the same as those of the 4-72 centrifugal fan.

Product Overview

The 4-72A centrifugal fan can convey air and other non-combustible gases that are harmless to the human body and non-corrosive to steel. The gas must not contain any viscous substances, and the content of dust and hard particles must not exceed 150mg/m³, and the gas temperature must not exceed 80℃. This fan is widely used in environmental protection and dust removal, industrial and mining enterprises, large buildings, hotels, restaurants, etc., for indoor ventilation, air exchange, and smoke exhaust.

Product Overview

The 4-72C centrifugal fan uses belt transmission, and the impeller is mounted on the transmission shaft, which can withstand high temperatures. Ordinary iron plates of type C can withstand 150℃, manganese plates can withstand 180℃, and 304 stainless steel can withstand high temperatures of 200-250℃.

It can convey air and other non-combustible gases that are harmless to the human body and non-corrosive to steel. This fan is widely used in high-temperature environments and large-scale occasions such as environmental protection and dust removal.

Performance Overview

1. The 4-72 centrifugal fan has good exhaust effect and is very suitable for pipeline exhaust or air supply.

2. Strong applicability. The 4-72 centrifugal fan is commonly used in pipeline air transportation, and can be used in places without corrosive, flammable, or explosive gases.

3. The 4-72 centrifugal fan adopts a reasonable impeller angle design based on air fluid mechanics. During operation, there is no mechanical friction, and the reasonable blade profile minimizes noise; the noise generated by the 4-72 centrifugal fan is high-frequency noise, and sound insulation can be achieved with obstacles.

4. Stable operation. The optimized impeller design minimizes axial force, and the high-efficiency impeller is corrected by static and dynamic balance, making the operation of the whole machine stable, and the bearing amplitude is relatively small without any vibration damping device.

5. Low maintenance. Because its impeller adopts a backward-curved design, it is not easy to adhere to dust and other media, and the motor uses imported bearings.

6. Convenient maintenance. Some models can be equipped with cleaning doors, and maintenance and cleaning can be performed without disassembling the machine, saving time and effort.

Purpose

The main purpose of the 4-72 centrifugal fan is for indoor ventilation and air exchange in general factories and large buildings, or for conveying air and other non-combustible, non-explosive, non-volatile gases that are harmless to the human body and non-corrosive to steel; the B4-72 centrifugal fan can exhaust flammable and volatile gases; the F4-72 centrifugal fan is mainly used for conveying corrosive gases. However, the gases conveyed by the 4-72, B4-72, and F4-72 centrifugal fans must not contain any viscous substances, and the content of dust and hard particles must not exceed 150mg/m³, and the gas temperature must not exceed 80℃.

The performance, optional parts, and base dimensions of the B4-72 fan are consistent with those of the 4-72 model, and can be selected according to its sample. The basic structure of this fan is the same as that of the 4-72 model. For №2.8A~6A, a B35 motor with flange and base is used; for N6~12C, D motors, the YB series corresponding to the Y series in the table is selected, and the installation type is B.

The F4-72 centrifugal fan is made of stainless steel, fiberglass, or other corrosion-resistant materials, and its performance and base dimensions are the same as those of the 4-72 centrifugal fan.

Type

Viewed from the motor end, impellers rotating clockwise are called "right-rotating fans", indicated by "right", and vice versa are called "left-rotating fans", indicated by "left".

The outlet position of the fan is indicated by the outlet angle of the casing. The 4-72 fan N2.8~6 is made into one type at the factory, and the user can install it to the required position according to the requirements. No need to specify when ordering. Among them: the outlet position adjustment range of N2.8 is 0°~225°, with an interval of 45°; the outlet adjustment range of N3.2~6 is 0°~225°, with an interval of 22.5°; the outlet adjustment range of N8~12 is 0°~225°, with an interval of 45°; the outlet angles of M16, 20 are fixed at three types: 0°, 90°, 180°, which cannot be adjusted, and need to be specified when ordering.

The fan has four types of transmission methods: A, B, C, and D. In the 4-72 fan, N2.8~5 uses A-type transmission, N6

has both A-type and C-type transmissions, N8~12 uses C and D type transmissions, and N16~20 uses B-type transmission. If the above model numbers, transmission methods, and outlet angles do not meet your production needs, our factory has the ability to modify or design them until you are satisfied.

Structure

The 4-72 centrifugal fan N2.8A~6A is mainly composed of impeller, casing, inlet, and motor. N6C and N8~20 have the above structure, as well as transmission parts.

Impeller - Composed of 10 backward-curved airfoil blades, a curved wheel cover, and a flat rear plate, made of steel plate (cast aluminum alloy for B4-72), corrected by static and dynamic balance and subjected to overspeed operation test, with high efficiency, stable and reliable operation, and good air performance.
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Housing - Made in two different styles: N2.8~12 housings are made as a whole and cannot be disassembled. N16~20 housings are made in three-piece style. In addition to being horizontally divided into two halves, the upper half is vertically divided into two halves along the center line and connected with bolts for easy installation and maintenance when inserting or removing the impeller.

Inlet - Made as an integral structure, installed on one side of the fan, with a curved cross-section parallel to the axis. Its function is to allow the airflow to smoothly enter the impeller with minimal loss.

Transmission - Consists of a main shaft, bearing box, rolling bearings, pulley or coupling.

Installation and Use

Before installation, conduct a comprehensive inspection of all parts of the fan, paying particular attention to the impeller, housing, main shaft, and bearings. If any damage is found, it should be repaired, and then the inside of the bearing box should be cleaned with kerosene.

The following three points must be noted during the installation process:

1. To prevent rust and reduce disassembly difficulties, apply a layer of lubricating oil or machine oil to some mating surfaces.

2. When tightening the bolts on the mating surfaces, if there are locating pins, install the pins first, then tighten the bolts.

3. Check the inside of the housing and other casings to ensure that no tools or debris have fallen or been left behind.

Installation Requirements:

1. When installing the fan, the weight of the air duct should not be placed on the housing. Correct the axial and radial clearances between the inlet and the impeller according to the drawings, and maintain the horizontal position of the shaft.

2. When installing the inlet pipe, the bolts on the inlet itself can be directly used for connection. In this case, the inlet is fixed by three countersunk screws.

3. When the outlet is installed at a certain angle, rotate the rear plate appropriately so that the nameplate is in a horizontal position. For N8~12, the angle steel flange surface should remain horizontal.

4. When installing the N8~12D fan, use a dial indicator and feeler gauge to measure the coaxiality of the fan main shaft and motor shaft, and the parallelism of both ends of the coupling. The coaxiality tolerance of the two shafts is 0.05m, and the parallelism tolerance of the coupling end faces is 0.1mm.

5. After the fan is installed, manually rotate the rotor to check for any tightness or scraping. Check if the wiring is correct, if other safety facilities are complete, and if personnel have left the rotating parts or inlet/outlet direction. Only after ensuring safety can the trial run be conducted.

6. After the motor is installed, install the pulley or coupling guard. If the air inlet is not connected to a pipe, a protective net or other safety device (provided by the user) must also be added. Other components should be installed according to the drawings.

Maintenance

1. Regularly remove dust, dirt, water, and other impurities from the fan and air ducts, and prevent rust.

2. When repairing the fan, the power must be cut off and the machine stopped. It is absolutely forbidden to perform repairs while the machine is running. The switch should be monitored by a designated person to prevent power from being accidentally supplied.

3. Regularly check the sensitivity of the thermometer and oil level gauge.

4. In addition to changing the lubricating oil after each disassembly and repair, the lubricating oil should also be changed regularly.

5. Before and after each maintenance, carefully record and count the number of tools and raw materials to prevent them from being forgotten inside the fan and pipes.

6. No one is allowed to stand within ten meters of the inlet and outlet during the fan test run.

7. Unauthorized personnel are strictly prohibited from being present during installation, maintenance, and testing.