Noise and quietness in stainless steel ventilation pipe will affect the inner lining of sound absorption pipe. The decibel of attenuation is the measurement of various shapes and sizes of lined and unlined rectangular pipes per foot of pipe length, as well as various frequencies of ventilation pipes in jinan Province.
The attenuation is related to the absorption coefficient, which is related to the pipe section size. It is found that the lining of Shandong ventilation pipe is closest to sivian's theoretical formula, rather than any other formula that has been put forward. The measurement is also carried out by noise from a 5000 CFM capacity fan connected to the system. It is found that noise is caused by friction.
At speeds of up to 1500 feet per minute, air with or without lining is negligible compared to the air inside the pipe, and the noise is generated by the fan blades. A special baffle structure is introduced into the flow system to measure the influence of static and air resistance. The friction resistance of the absorber lined pipe is the same as that of the unlined pipe.
When the ventilation channel is parallel with the external air channel, the wheel type heat exchanger can be used. Half of the wheel is in one pipe, half in the other.
When the Shandong air duct wheel rotates, the wheel part of the heating furnace pipe heats the perforated wheel structure. The part of the wheel in the cooling pipe removes heat from the perforated wheel structure. Wheels can also be treated with desiccant so that water can also be transferred from one stream to another.
The wheels are not completely sealed and the volume of the wheels themselves leaks from one pipe to another. Therefore, applications that require zero transfer (cross contamination) between flows cannot use wheels. Wheels need to be side-by-side and the same size of pipe, limiting the freedom of packaging required by many applications. Last but not least, the wheel is an active moving machine with motor, drive belt, pulley, bearing, etc. it requires highly skilled maintenance personnel to keep the wheel rotating.