Sanat Prozheh Toos Company has done several researches in the field of silencers performance. The diagrams below show two examples of sound measurement results, before and after the silencer is installed.
In the above diagram, the amount of sound at different frequencies is plotted at the TBS pressure reducing stations before and after the silencer is installed. As can be seen, the volume of TBS sound level appears mostly in the frequencies of 1000 to 4000 Hz; That is the critical frequencies at the pressure reducing stations are in this range.
The line with circular markers corresponds to the station without silencer, which is at a higher level. As shown in the figure, with the installation of the silencer, the amount of sound is reduced to lower levels (line with square indicator). According to the diagram, it is clear that the silencer performed well in the critical frequency range and was able to cut the peak of the diagram. In this silencer sample, which was tested in Mashhad, the amount of sound was reduced by 21 decibels.
The next point in the silencer's performance is related to the flow rate changes and the amount of silencer noise reduction. In this experiment, the amount of sound at different flow rates before and after the silencer is installed is plotted, which can be seen in the diagram opposite. According to this diagram, it can be seen that with increasing flow, the silencer performance has not changed and still has an effective noise reduction.