The fan is the power device of the kitchen exhaust ventilation system. When selecting a fan, it is necessary to master the general technology of the fan and the special technology of the kitchen fan. Among the equipment of the smoke exhaust ventilation system, the ventilator is one of the more complex technical structures and involves professional gateways and equipment. Due to the limitation of the structural space of the kitchen, the path direction and cross-sectional area of various pipes are mostly room. The selection of the fan becomes the key to determine the performance and work efficiency of the system. To this end, the fan selection method must be clearly defined.
(1) Determine the design conditions: Determine the design conditions such as the location space that can be used for the design according to the environment and design requirements, and determine the calculation basis for the air volume according to the actual needs. First of all, it is necessary to determine the preliminary planning such as the size, location, and pipeline direction of the exhaust hood, so as to provide a calculation basis for the calculation of the discharge volume. To supply fresh air, it is necessary to determine the basis for calculating the volume of fresh air in the space. To supply fresh air between the main kitchen and non-staple food processing rooms, the exhaust air volume should be determined first, and then the air supply volume should be calculated. To calculate the ventilation air volume, it is necessary to determine the volume size of the ventilation space.
(2) Calculate the required air volume: The system must be carefully analyzed, and the required air volume should be calculated by theoretical methods. The size of the air volume is one of the important parameters for fan selection.
(3) Pipeline connection design: Determine the cross-sectional area and direction of the exhaust pipe according to the calculated required air volume, design the pipeline connection on the drawing, determine the length of the pipe and the connection of components, and determine the calculation conditions for the pressure loss calculation.
(4) Calculate system resistance: Calculate the pressure loss of each main and auxiliary pipeline according to the pipeline connection diagram, and obtain the system pressure loss. Fan pressure is another important parameter for fan selection.
(5) Select the type of fan: determine the type of fan selected according to the calculated air volume and pressure. There are many types of fans, but the most commonly used fans in public kitchens are mainly centrifugal fans and axial fans. For systems that exhaust smoke or require high pressure, centrifugal fans or centrifugal air cabinets should be used.
(6) Select the fan model: the fan that meets the rated air volume and rated pressure requirements may have multiple models and machine numbers. It is necessary to combine the conditions required by the fan’s purpose, process requirements, use occasions, environmental protection requirements, structural materials, etc., select the model firstand then select the machine number. If the air volume and pressure are close to the process requirements, and the fan models and machine numbers that meet other requirements, should be analyzed and compared with reference to the technical data.
(7) Determine the installation form: the installation of the fan includes floor installation, side wall installation, roof hoisting and other forms. Centrifugal fans, centrifugal air cabinets, and air inlet positions, air outlet positions, size and weight are different. requirements, the selected models and machine numbers are also different. When choosing a fan, it is necessary to consider the construction process, actually investigate the site, master the details of the installation environment, and determine the installation form of the fan. This is the difference between the design of the kitchen exhaust ventilation system and other engineering designs. The structural environment of the kitchen has an impact on the details of the fan transportation channel, hoisting environment, installation space, the direction of the fan inlet and outlet, the load of the installation position, the pollution and noise interference to the surrounding environment, etc. Take evasive measures when choosing a fan.
(8) Complete the connection design: According to the size of the air inlet and outlet of the selected fan, the connection design and specific installation design with the ventilation duct are carried out.