Model 4-68 Centrifugal Blower

I. Application of the Fan:
4-68 Type Centrifugal Blower (hereinafter referred to as the blower) can be used for general ventilation and air exchange. The operating conditions are as follows:
1. Application: Suitable for indoor ventilation and air exchange in general factories and large buildings, it can be used for both intake and exhaust of gases.
2. Types of gases conveyed: air and other non-flammable, non-toxic to humans, and non-corrosive to steel materials.
3. Impurities in the Gas: No sticky substances are allowed in the gas, and the dust and hard particle content should not exceed 150 milligrams per cubic meter.
4. Gas temperature: No more than 80 degrees.
Section II: Type of Fan
1. This fan is designed for single吸入, featuring models such as №2.8, 3.15, 3.55, 4, 4.5, 5, 6.3, 8, 10, 12.5, 16, and 20, totaling twelve models.
2. Each type of fan can be manufactured in either right-rotating or left-rotating models. When viewed from the positive end of the motor, the impeller rotates clockwise, referred to as a right-rotating fan, indicated by "right." Rotating counterclockwise is called a left-rotating fan, indicated by "left."
3. The exhaust position of the fan is indicated by the outlet angle of the housing. Both "left" and "right" can be made in 0°, 45°, such as 135°, 180°, 225°, a total of six angles.
4. Fan drive methods: There are four types, A, B, C, and D. No. 2.8-5 uses type A, directly connected to the motor for transmission. The fan blades and housing are directly mounted on the motor shaft and flange (motor type D2/T2). No. 6.3-12.5 employs a cantilever support device, which is further divided into two transmission methods: type C (belt drive pulley on the outer side of the bearing) and type D (connected by a coupling). No. 16 and 20 use type B cantilever support, with belt drive, the pulley located in the center of the bearing.

Section 3: Structural Characteristics of Main Components
The No. 2.8-5 4-68 type fan is mainly composed of a impeller, housing, and inlet, etc., paired with a direct-connected electric motor. The No. 6.3-20, in addition to the aforementioned parts, also includes a transmission section.
1. Impeller: Consists of 12 backward-tilted blade-type blades welded between a conical wheel cover and a flat wheel disk. Made of steel plates and balanced statically and dynamically, it offers excellent air performance, high efficiency, and smooth operation.
2. Shell: The shell is a helical body made of ordinary steel plate welding. It is available in two different types: the #2.8-12.5 shell is made as a single unit, non-detachable. The #16 and #20 shells are designed as three-piece, with the upper half further divided along the vertical centerline, in addition to being split into two along the horizontal center plane, and are bolted together.
3. Inlet: Formed into a streamlined overall structure with a converging shape, securely fastened with bolts to the fan's inlet side.
4. Transmission Group: Comprising the main shaft, bearing housing, rolling bearings, pulley or coupling, etc. The main shaft is made of steel. For models No. 6.3-12.5 fans, the bearing housing has an integral structure, equipped with a thermometer and oil level indicator on the bearings. Models No. 16 and 20 fans use two parallel bearing supports, with a thermometer mounted on the supports and lubricated with bearing grease.