Design of the Downstream End Structure of Spray Nozzle
The downstream end structure of spray nozzle is an important part of the design of spray nozzle and is divided into two categories of flow passage structure and anchoring structure.
1 Flow Passage Structure
The flow passage structure of the spray nozzle mainly includes the periphery of the spray outlet, and the inner and outer flow channels, core components and Air intake baffle and so on.
1.1 Peripheral Sandwich Structure of Spray Outlet
The nozzle holes of the spray nozzle can be drilled with 0.5mm to 5mm, and the flow structures of the nozzle holes are mainly cylindrical, conical and parallel fan-shaped structures. The sandwich structure of the nozzle hole has the advantages of large flow rate and large nozzle angle, and can spray smaller particles. The sandwich structure of the nozzle hole also has its own limitations, due to the limited space for the nozzle hole and its small size, the nozzle structure is difficult to design and the materials used are limited.
1.2 Internal and External Channels
The internal and external channels are the main parts of the flow passage structure of the spray nozzle. They form the space where the liquid flows from the nozzle entrance to the nozzle exit, and then spray outward. The internal channel is mainly composed of head parts, flow plates, central rods, and divergent nozzles. The internal diameter of the internal channel is 0.5mm to 1mm, and its length is generally 2mm to 20mm.
Both the internal and external channels need to be carefully designed in order to reduce the pressure drop in the fluid flow path. Generally speaking, the diameter of the external channel should be larger than that of the internal channel, so as to ensure that the flow has a larger cross-sectional area and a larger flow rate.
1.3 Core Components and Air Intake Baffle
The core components of the spray nozzle mainly include nozzle support structure, atomized liquid supply components, rotating structure and swash plate. The nozzle support structure is used to provide a firm and stable support for the nozzle outlet, so that the liquid will not be distorted during the spray process. The atomized liquid supply components need to provide enough pressure to make the liquid atomized. The rotating structure is used to evenly spray the liquid.
The air inlet baffle is composed of curved plates and fine hole air intake plates. After the dust enters the spray nozzle, it is bound by the centrifugal force generated by the liquid flow, and eventually enters the dust removal filter at the lower part of the spray nozzle.
2 Anchorage Structure
The anchor structure is used to fix the spray nozzle to the system, and is usually composed of screws, bushes and holders. The main purpose of the anchoring structure is to ensure the position accuracy of the spray nozzle to the system, and to prevent the spray nozzle from rotating and separating from the system during the spray process.
The structure of the anchoring screws varies with the size and shape of the spray nozzle. Generally, the common structure of the anchoring screws for the spray device is flat head or countersunk head as shown in Figure 1.
The anchor bushes also need to be designed in consideration of the anchor structure and dynamic force during the spray process. The most common bushing structures used in spray nozzle are round bushes and hexagonal bushes.
Finally, the holder is used to fix the anchoring screws and the anode block together. The holder can be made of materials such as brass, steel, aluminum and stainless steel, depending on the application.
To sum up, the design of the downstream end structure of the spray nozzle includes flow passage structure and anchorage structure. Flow passage structure includes nozzle hole peripheral structure and internal and external channels, as well as core components and air intake baffle. The anchoring structure is composed of anchors, bushes and holders. The design of the downstream end structure of the spray nozzle should be based on the actual conditions and requirements of the system, such as size and material, so as to ensure the safe and reliable operation of the spray nozzle.
