减压孔板快速计算书.doc

减压孔板在室内给排水工程中，减压孔板可用于消除给水龙头和消火栓前的剩余水头，以保证水系统均衡供水，达到节水、节能的目的。（1） 减压孔板孔径的计算：水流通过孔板式的水头损失，按式中计算： 1式 式中 H水流通过孔板的水头损失值（104Pa）； 孔板的局部阻力系数； 水流通过孔板后的流速（m/s）； g重力加速度（m/s）。 值可从下列式中求得： =1.75D2d21.1-d2D21.175-d2D2-12 2式 式中 D给水管道直径（mm）； d孔板孔径（mm）。 为简化计算，将各种不同管径及孔板孔径代入公式1式、2式，求得相应的H值，所得计算结果列于表1.使用时，只要已知剩余水头H1及给水立管直径D，九可从表中查的所需孔板孔径d。表1： 减压孔板的水头损失D（mm）d(mm)34567891011121315202532405081.03262.3024.5481.03201.779.4932.1681.03222.214.2514.9138.13105.59262.302.097.6819.9856.00140.021.104.2511.3132.1681.03201.770.592.486.7919.6149.84124.800.331.514.2512.5332.1681.030.180.942.758.3021.5654.700.090.591.835.6714.9138.13 0.040.381.243.9610.5827.30D（mm）d(mm)1415161718192021222324202532405070801000.240.862.837.6819.9881.03140.820.150.592.055.6714.9160.98105.590.090.421.514.5211.3146.6981.03201.770.050.291.123.238.7136.3063.13157.610.030.200.842.486.7928.5949.84124.800.010.140.631.925.3422.7839.83100.020.090.471.514.2518.3532.1681.030.060.361.183.4114.9126.2266.280.040.270.942.7512.2221.5654.70 0.020.200.752.2410.1017.8745.500.010.150.591.838.4014.9138.13D（mm）d(mm)25262728293031323332405070801001251500.110.471.517.0312.5332.1681.04170.850.080.381.245.9110.5827.3068.99145.600.060.301.035.008.9923.2959.07124.800.040.240.854.257.6019.9850.74107.540.020.190.713.636.5817.2343.8993.130.010.150.593.115.6714.9138.1481.030.120.502.674.9012.9733.2870.800.090.422.314.2511.3129.1062.110.070.351.993.709.9125.5954.70 D（mm）d(mm)343536373839404142405070801001251500.050.291.733.238.7122.5948.340.040.241.512.837.6820.0042.870.030.201.312.486.7917.7238.130.020.171.152.186.0115.7934.020.010.141.001.925.3414.1030.430.010.881.704.7612.6027.300.090.771.514.2511.3124.540.080.681.333.8010.1822.120.060.591.183.419.1619.90 D（mm）d(mm)4344454647484950515070801001251500.050.521.053.068.2818.090.040.460.942.757.4916.410.030.400.842.486.7814.910.020.360.752.246.1513.580.010.310.672.025.5912.380.010.280.581.835.1011.310.240.531.664.6610.350.210.471.514.259.490.190.421.373.908.71 D（mm）d(mm)52535455565758596070801001251500.160.381.243.568.000.140.341.133.277.360.120.301.033.006.790.110.270.942.766.260.090.240.862.535.780.080.220.782.345.340.070.190.712.154.950.060.170.651.984.580.050.150.591.834.25 D（mm）d(mm)61626364656667686970801001251500.040.140.541.693.950.030.120.501.563.670.030.110.451.453.410.020.090.421.343.170.020.080.381.242.950.010.070.351.152.750.010.060.321.072.570.050.290.992.400.050.270.922.24D（mm）d(mm)707172737475767778801001251500.040.240.852.090.030.220.791.960.030.200.741.830.020.180.691.710.020.170.641.610.010.150.591.510.010.140.551.410.010.130.511.320.110.481.24D（mm）d(mm)7980818283848586871001251500.100.451.170.090.411.100.080.391.030.080.360.970.070.330.910.060.310.860.050.290.800.050.270.760.040.250.71D（mm）d(mm)8889909192939495961001251500.040.230.670.030.220.630.030.200.590.020.190.560.020.170.530.010.160.500.010.150.470.010.140.440.010.130.42D（mm）d(mm)9798991001011021031041051251500.120.390.110.370.100.350.090.330.090.310.080.290.070.270.070.260.060.24D（mm）d(mm)1061071081091101111121131141251500.050.230.050.210.040.200.040.190.040.180.030.170.030.160.020.150.020.14D（mm）d(mm)1151161171181191201211221231251500.020.130.010.120.010.110.010.110.010.100.010.090.090.08注：表中给水管计算管径均采用公称直径表1中数据是假定水流通过孔板后的流速为1m/s时计算得出的，如实际流速与此不符，则应按式3进行修正，并安修正后的剩余水头查表。 H1=H2*1 (104Pa) 3式式中 H1修正后的剩余水头 （104Pa）； 水流通过孔板后的实际流速（m/s）； H设计剩余水头（104Pa）。