楊福斗英語翻譯2

1、 LESSON 18Section 3 Mechanical Ventilation楊福斗 譯Mine Ventilation The application of fans to induce airflow is common in the mining industry. The majority of modern mine fans are the axial-flow type. However, many centrifugal fans still are in use and may be preferred for some applications. 用扇風機來產(chǎn)生風流在

2、采礦業(yè)是普遍的。大多數(shù)現(xiàn)代的礦井扇風機是軸流式的，不過許多離心式扇風機仍然在使用，可以作為某些應用領域的首選。 The general fan laws are the same for either axial-flow or centrifugal fans， The only differences are in the individual characteristics of power, pressure and air volumes【vljums】.不論是軸流式扇風機還是離心式扇風機不論是軸流式扇風機還是離心式扇風機，其一般規(guī)律都是相同的，唯一的區(qū)別，其一般規(guī)律都是相同的，唯一

3、的區(qū)別是在于功率是在于功率 ，壓力和風量的個體特征。，壓力和風量的個體特征。1.Air quantity varies directly as 1.Air quantity varies directly as fan speed. Quantity is independent of fan speed. Quantity is independent of air density(twice the volume requires air density(twice the volume requires twice the speed)twice the speed)。 扇風機的風量與轉(zhuǎn)

4、速成正比。風量與空氣密度無關（兩倍的風量需要兩倍的轉(zhuǎn)速）。 Fan Laws-These are as follows:Fan Laws-These are as follows: 2. Pressures induced vary directly as fan speed squared, and directly as density(twice the volume develops four times the pressure).產(chǎn)生的壓力與轉(zhuǎn)速平方成正比，與密度成正產(chǎn)生的壓力與轉(zhuǎn)速平方成正比，與密度成正比（兩倍的風量可以產(chǎn)生四倍的壓力）。比（兩倍的風量可以產(chǎn)生四倍的壓力）。3.T

5、he fan power-input varies directly as 3.The fan power-input varies directly as the fan speed cubed. and directly as the the fan speed cubed. and directly as the air density (twice the volume requires air density (twice the volume requires eight times the power)eight times the power) 扇風機的輸入功率與扇風機轉(zhuǎn)速的立

6、方成正比，與空氣密度成正比(兩倍的風量需要八倍的功率) 4 .The mechanical efficiency 4 .The mechanical efficiency of the fan is independent of of the fan is independent of fan speed and air density.fan speed and air density. 風機的機械效率，與風扇轉(zhuǎn)速和空氣密度無關。 Selection of FansThe performance of a Selection of FansThe performance of a fan i

7、n a ventilating system is determined fan in a ventilating system is determined by its characteristic curve and the mine by its characteristic curve and the mine resistance if acting alone an the system, resistance if acting alone an the system, and by its characteristic curve, and by its characteris

8、tic curve, characteristics of other pressure sources, characteristics of other pressure sources, and and the resistance of individual zones the resistance of individual zones of of influence if acting in combination with influence if acting in combination with other pressure sources.other pressure s

9、ources. 扇風機的選擇如果是單一形式的通風系統(tǒng)，在一個通風系統(tǒng)中的風機工況取決于它的特性曲線和礦井阻力，如果是與其它壓力源相配合的，取決于扇風機的特性曲線、其他壓力源的特性和局部阻力的影響。Fan characteristics are a matter Fan characteristics are a matter of design,which is controlled by of design,which is controlled by the manufacturer.The resistance of the manufacturer.The resistance of

10、the mine is a matter of layout and the mine is a matter of layout and maintenance of the ventilating maintenance of the ventilating network, and is controlled by the network, and is controlled by the mine operator.mine operator. 扇風機特性取決于設計的問題，是由制造商控制的。礦井阻力取決于通風網(wǎng)絡的布局和維護的問題，是由礦井施工者控制的。 The amount of a

11、irflow induced in a The amount of airflow induced in a mine will depend on fan characteristic mine will depend on fan characteristic and mine resistance.The pressure( H) and mine resistance.The pressure( H) required to pass a quantity(Q) through a required to pass a quantity(Q) through a mine or seg

12、ment of a mine is expressed mine or segment of a mine is expressed by the common formulaby the common formula H=RQ H=RQ2 2，where Rwhere R，the the resistance factor, may be calculated resistance factor, may be calculated from known pressure losses or from the from known pressure losses or from the Co

13、mmon formula.Common formula. 在礦井中產(chǎn)生的風流量取決于扇風機的特性和礦井阻力。通過礦井或礦井區(qū)段的風量Q所需的風壓H是通用公式H=RQ2 來表示的，式中R，是通風阻力系數(shù)，可以利用已知的壓力損失或通用的公式計算得出。 Mine fans are available to suit Mine fans are available to suit most conditions of mine resistance most conditions of mine resistance and desired volume relationships.and desir

14、ed volume relationships. 礦井扇風機在滿足礦井阻力和所需風量關系的大多數(shù)狀況下是可以利用的。Modern axial-flow fans are built Modern axial-flow fans are built with variable-pitch blades that with variable-pitch blades that permit a wide range of application permit a wide range of application for the single fanfor the single fan，The v

15、arious The various blade settings permit the same fan blade settings permit the same fan to operate through a wide range of to operate through a wide range of mine-resistance relationships.mine-resistance relationships. 新式的軸流式風機具有可變螺距葉片，允許同一臺扇風機有各式各樣的應用，不同的葉片安裝形式允許同一臺扇風機在各式各樣的礦井通風阻力關系下運行。All fan-per

16、formance data are based All fan-performance data are based u p o n a s t a n d a r d d e n s i t y o f u p o n a s t a n d a r d d e n s i t y o f 0.0750.075pcfpcf.At altitudes where the air .At altitudes where the air density is substantially less than density is substantially less than standard, corrections m