When designing porous diffusion muffler, it is necessary to consider that the installation of muffler will not affect the emission of airflow, but also meet the requirements of reducing noise. The design method is to find out the diffusion cross-sectional area ratio satisfying the noise reduction value given in Figure 2 from the stagnation pressure (or gas tank pressure) of the port A of the pipeline, and then find out the model of powder copper cylinder or wire mesh satisfying this cross-sectional area ratio from the attached table, and multiply the cross-sectional area of the port A of the pipeline by this diffusion ratio to obtain the total cross-sectional area of the outlet surface of the porous diffusion muffler. According to this area, the muffler can be made into the shape shown in figure 1, b or any other shape that is beneficial to the strength, processing and practicability of the muffler. The above is the ideal situation. In fact, the noise generated by small holes may not be completely ignored, and some practical factors are not taken into account, so the noise reduction value is often lower than that in Figure 2. However, it is easy to reduce the noise of 30 ~ 50 decibels with a porous diffusion muffler.
In order to ensure the exhaust rate, the exhaust surface area of the actual porous diffusion muffler is slightly larger than the calculated value; Mufflers should be cleaned regularly in use to prevent dust particles from accumulating and blocking the airflow channel.