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.

　　衰减与吸收系数有关，吸收系数与管道截面尺寸有关，研究发现，山东通风管道的衬砌与Sivian的理论公式更接近，而不是其他任何已经提出的公式。该测量还通过连接到系统的5000cfm容量风扇的噪声进行。人们发现噪音是由摩擦产生的。

　　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.

　　在高达每分钟1500英尺的速度下，无论是有内衬还是没有内衬的空气，与管道内壁的空气相比都是微不足道的，噪音是由风扇叶片产生的。在流动系统中引入了一种特殊的挡板结构来测量静度和空气阻力的影响。吸收剂衬里管的摩擦阻力与未衬里管的摩擦阻力测量方法相同。

　　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.

　　当通风道与外风道并列时，可采用轮式换热器。轮子的一半在一根管子里，一半在另一根管子里。

　　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.

　　当山东风管轮转动时，加热炉管中的车轮部分对穿孔车轮结构进行加热。位于冷却管中的车轮部分从穿孔的车轮结构中去除热量。轮子也可以用干燥剂处理，这样水也可以从一条小溪转移到另一条小溪。

　　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.
 

　　车轮没有完全密封，车轮本身的体积从一个管道泄漏到另一个。因此，需要在流之间零转移(交叉污染)的应用程序不能使用轮子。车轮需要并排和同样大小的管道，限制了许多应用程序所需的包装自由度。但并非更不重要的是，轮子是带有马达、传动带、滑轮、轴承等的主动移动机器，需要高技能的维修人员来保持轮子转动。

　　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.