WKF series caseless fan is designed from the perspective of economy, high efficiency and saving working space. It does not have ordinary centrifugal fan volute. It is mainly used on the air processor composed of enclosed space areas or buildings to provide pressurized air for the whole environment, so as to allow the air duct to be connected to the air processor from any direction. This design saves space because there is no fan volute, transfer section and diffusion section in the air processor. The specific features of the product are described as follows:

一、Product structure and description

二、Product structure and description

1. WKF series caseless fan is mainly composed of motor, air inlet side plate, support plate, air inlet, impeller, impeller hub, base and other parts. The air inlet side plate, support plate, air inlet and impeller are made of high-quality steel plate. The base is welded by angle steel or channel steel, and the surface is sprayed with plastic or paint, with strong anti rust and anti-corrosion ability.

2. The impeller blade is backward inclined wing shape, which has the advantages of high efficiency, high pressure head and low noise.

3. Before leaving the factory, the fan is tested at the working speed, and the impeller balance accuracy grade is G6 3。

三、 Before selecting the fan, the user shall consider the inlet loss of the supply air duct. The correction coefficients of different types of air duct inlets and positions are also different, which can be corrected according to the following table.

　　It can be seen from the above table that the air duct with diffusion section can effectively reduce the inlet loss of the air duct. In addition, the loss of radial air supply is smaller than that of axial air supply inlet. For fans with multiple openings, the opening with the maximum loss is selected as the calculation basis of pressure loss. For example, the system requires air volume of 26000m3 / h, static pressure of 1100pa, standard air density, air duct diameter of 0.6m, radial air supply with diffusion section, and determine the static pressure of the selected fan: air duct area = π × (0.6 ÷ 2) 2 = 0.2826m2 duct velocity = 26000 ÷ 3600 ÷ 0.2826 = 25.5m/s duct dynamic pressure = 25.52 × 1.2 ÷ 2 = 390pa (standard working condition) inlet loss correction coefficient = 1.1 × Dynamic pressure in the air duct = 429pa, so the static pressure of the selected fan = 1100 + 429 = 1529p

四、Product installation instructions

　　When the shell less fan supplies air to the outside through an enclosed space, in order to ensure free suction and free exhaust, the optimal space size shall comply with the following provisions:

Space radius at air inlet a ≥ 0 5 D

Axial dimension L ≥ D in axial air supply, and l is not required in radial air supply

Radial dimension B ≥ 0 5 D

五、Description of technical parameters

1. The data listed in the sample are measured under standard conditions, i.e. atmospheric pressure = 101 3 2 5 K p a, gas density = 1 2 k g / m3, gas temperature = 20 ° C. 2 .  The fan noise shall be measured on the axis of the air inlet and one meter away from the air inlet according to the national standard.

3. The motors equipped include variable frequency motor and Y series motor. When selecting variable frequency motor, the frequency can be adjusted arbitrarily without exceeding the current and the maximum speed of the fan.

4. When the variable frequency motor is selected, the flow and static pressure given in the technical parameter table are not one-to-one corresponding relationship. It represents the flow range and static pressure range between multiple speeds. The specific relationship between flow, static pressure and speed should be found from the performance curve.