PRSDM645-010K0-100/15-71B1 伺服电机应用于传输过程控制 ABB
e、 认识到，在不太复杂的空间，如商店或设备室，预计会出现一些声音和振动，并且在
更别，因此HVAC设计师必须首先了解起源，
然后是可接受的性能水平，后是机制
控制声音和振动，以达到可接受的服务水平。
“声音”是传输到
耳或等效声传感装置。当声音冒犯时
这叫做“噪音”声功率级以瓦特为单位测量，并且
10 12 W为听力阈值，定义为0分贝
（dB）。声音通常在每个倍频带内测量，
其中，每个连续倍频带的频率是
前一个。31.5赫兹或每秒周期的振动频率
（Hz）定义一倍频程带的中点。中间C在
五倍频程的中间，频率为504Hz。
声音或噪音是由运动中的物体产生的
空气振动。声音从原点“辐射”到
检测点。露天环境中的声功率级随着
距离的平方，但在较小的受限空间中，具有
声功率级可以在距离上相对恒定。声音可以通过吸收或限制来控制。稠密的
纤维垫和声学管道衬里是吸收材料的例子。砖石或混凝土结构，以及噪音周围的铅织物
发电机是限制（安全壳）的例子。组合
暖通空调工程基础：1部分
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暖通空调工程基础：1部分11
限制和吸收通常用于控制或消除
系统产生声音。
当周期运动的影响
一件设备的一部分被带入并穿过结构
根据定义，感觉到刺激或冒犯的点。
任何稍微失去平衡的旋转设备都可以设置
增加振动。振动通常在结构中传递到远处
要点。坐在书桌旁的人可以感觉到地板或书桌
振动。实验室工作台上的一盘液体可能会呈现波形
表面上的结构振动。即使暴风雨也能
导致建筑物震动，空气在管道中流动或
管道中流动的流体会引起振动和噪音。
好通过平衡和隔离来控制振动。平衡
移动部件消除了其原点的振动。对于大型元件，如风扇、压缩机和发动机，采用弹簧隔离
或弹性垫是常见的做法。较低频率的振动需要更多的初始弹簧偏转才能有效。必须消除振动元件与其环境的任何硬物理连接。因此，所有管道和导管或管道连接必须灵活
有联系的。这也有助于确保设备：
不承受连接管道的重量。
关于这一问题的进一步讨论，见20章和参考文献7。
1.10节能
定期的国际活动提醒我们能源在
发达国家的经济福祉。共同的能力
工业国家的人民比国王过着更富裕的生活
而过去的女王与能源仆人直接相关。
运输公司
SDM645-010K0-100/15-71B1 伺服电机应用于传输过程控制 ABB
SDM645-010K0-100/15-71B1 伺服电机应用于传输过程控制 ABB
e. Recognize that in less sophisticated spaces like shops or equipment rooms, some sound and vibration is expected and tolerated at
higher levels, so the HVAC designer must understand first the origins,
then the level of acceptable performance, and finally the mechanisms
of control of sound and vibration to achieve an acceptable level of service.
‘‘Sound’’ is a generic term for airborne vibrations transmitted to the
ear or equivalent acoustic sensing device. When sound offends, it is
called ‘‘noise.’’ Sound power levels are measured in watts, and with
1012 W being a threshold of hearing, this is defined as being 0 decibels
(dB). Sound is usually measured within and for each octave band,
where the frequency of each successive octave band is twice that of
the previous. A vibration frequency of 31.5 hertz or cycles per second
(Hz) defines the midpoint of the first octave band. Middle C is in the
middle of the fifth octave band at 504 Hz.
Sound or noise is generated by something in motion which sets up
airborne vibration. The sound ‘‘radiates’’ from the point of origin to
the point of detection. Sound power levels in open air diminish with
the square of the distance, but in a smaller confined space, with high
reflectance, the sound power level may be relatively constant over distance. Sound may be controlled by absorption or confinement. Dense
fibrous mats and accoustical duct liner are examples of absorptive materials. Masonry or concrete structure, and lead fabrics around a noise
generator are examples of confinement (containment). Combinations
HVAC Engineering Fundamentals: Part 1
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HVAC Engineering Fundamentals: Part 1 11
of confinement and absorption are often used to control or eliminate
system-generated sound.
Vibration becomes a problem when the effects of the cyclical motion
of a piece of equipment are carried into and through the structure to
a point where it is sensed, by definition, as an irritation or offense.
Any rotating piece of equipment that is slightly out of balance can set
up a vibration. Vibrations are often carried in structures to remote
points. A person sitting at a desk may sense the floor or the desk
vibrating. A pan of liquid on a laboratory table may exhibit waveforms
on the surface from structural vibrations. Even as windstorms can
cause buildings to shake and tremble, so can air moving in ducts or
fluid moving in pipes give rise to vibrations and noise.
Vibration is best controlled by balance and isolation. Balance of
moving components eliminates vibration at its origin. For large elements such as fans, compressors, and engines, isolation with springs
or resilient pads is common practice. Lower-frequency vibrations require more initial spring deflection to be effective. The vibrating element must be relieved of any hard physical connection to its environment. Hence all pipe and conduit or duct connections must be flexibly
connected. This is also helpful in making sure that the equipment does
not carry the weight of the attached piping.
See Chap. 20 and Ref. 7 for further discussion of this issue.
1.10 Energy Conservation
Periodic international events remind us of the vital role of energy in
the economic well-being of developed countries. The ability of common
folk in the industrial nations to live more opulent lives than the kings
and queens of yesteryear is directly related to the energy servant.
Transportation, co
SDM645-010K0-100/15-71B1 伺服电机应用于传输过程控制 ABB
