孔板文檔資料

煤層瓦斯壓力參數(shù)測(cè)定-PAGE6-孔板流量計(jì)抽放管路中的瓦斯流量測(cè)定與計(jì)算瓦斯量是一種氣體，用來(lái)測(cè)定氣體流量的儀表形式和種類(lèi)較多，但在礦井抽放瓦斯管路中大都使用孔板流量計(jì)，其結(jié)構(gòu)如圖19。圖19孔板流量計(jì)10.1參數(shù)測(cè)定(1)測(cè)定孔板上風(fēng)端的絕對(duì)壓力(Pl),可用真空表(負(fù)壓表)或U型汞柱計(jì)直接測(cè)定，并按下式計(jì)算：Pl＝Pa－P(10―1)式中：Pl＝――孔板上風(fēng)端的絕對(duì)壓力，(mmHg)Pa――大氣壓力，(mmHg)P――表壓力或水銀柱高差，(mmHg)。(2)測(cè)定管內(nèi)氣體溫度(ｔo)，可近視取測(cè)量地點(diǎn)溫度。(3)測(cè)定孔板前后端壓差(Δh)，用U型水柱計(jì)測(cè)量。(4)測(cè)定管內(nèi)瓦斯?jié)舛?x)，氣樣可用高負(fù)壓抽氣筒采集，見(jiàn)圖20。采用時(shí)，抽氣筒的進(jìn)氣口和平衡壓力口分別通過(guò)膠管與孔板前后的氣咀相連通，起著平衡負(fù)壓和保證抽氣筒前方壓力大于后方壓力的作用，因而避免了經(jīng)活塞漏入空氣。在打氣時(shí)，瓦斯經(jīng)氣門(mén)芯排到高濃度瓦斯檢定器中。圖 20FW-1型高負(fù)壓瓦斯采樣器10.2流量計(jì)算Q＝Kb(10－2)式中：Q流――用標(biāo)準(zhǔn)孔板觀測(cè)時(shí)混合瓦斯流量，m3/min；K――孔板實(shí)際流量系數(shù)，K＝189.76aomD2(10－3)ao――標(biāo)準(zhǔn)孔板流量系數(shù)；m――截面比；m＝D――管道直徑，m；Δh――在孔板前后端所測(cè)之壓差，mmH2O。δT――溫度校正系數(shù)；δP――壓力校正系數(shù)；δT＝(10－4)δP＝(10－5)實(shí)際孔板流量特征系數(shù)K值表表10－4管徑D(mm)ma0K0.050.100.150.200.250.300.350.400.450.500.550.600.650.7015a00.61550.61920.62570.63350.64260.65320.66540.68150.69920.71920.74060.76730.79610.8223K0.00130.00260.00400.00540.00690.00700.00990.01180.01340.01540.01740.01970.02210.024620a00.61510.61880.62520.63300.64230.65280.66470.68080.69840.71840.73980.76640.79530.8218K0.00230.00470.00710.00960.01220.01250.01770.02070.02390.02730.03090.03490.03930.043725a00.61370.61840.62470.63250.64170.65240.66400.68010.69760.71760.73900.76550.79450.8215K0.00370.00730.01110.01500.01900.02320.02750.03220.03710.04250.04810.05440.06120.068138a00.61370.61730.62340.63130.64020.65120.66240.67830.69540.71540.73710.76330.78230.8208K0.00840.01690.02560.02360.03290.04250.05250.06340.07480.08700.10010.11450.13010.146450a00.61280.61620.62210.62930.63870.64920.66070.67640.69340.71340.73500.76100.79000.8200K0.01450.02920.03330.04870.06330.07990.09720.11590.13550.15670.17930.20410.23110.259875a00.61090.61400.61960.62610.63570.64600.65740.67270.68920.70920.73100.75650.78580.8185K0.03060.06550.09920.13370.16960.20620.24560.28720.33100.37850.42920.48450.54520.6116100a00.60900.61170.61700.6238063270.64280.65410.66900.68500.70500.72700.75200.78150.8170K0.05780.11610.17550.23660.30010.35470.42310.49650.57360.65760.74610.84360.95131.0726125a00.60780.61050.61600.62230.63100.64110.65240.66750.68350.70320.72520.75000.77940.8145K0.09010.18100.27400.36900.46770.57030.67700.79170.91201.04251.18261.33431.50211.6905150a00.60670.60930.61500.62090.62940.63940.65060.66600.68200.70150.72350.74800.77730.8120K0.12930.26020.39390.53020.67180.81900.97221.13741.31031.49761.69901.91622.15722.4268175a00.60550.60810.61340.61950.62770.63770.64880.66450.68050.69980.72180.74600.77510.8095K0.17600.35340.53470.72000.91201.11181.31971.54471.78002.03342.30712.60122.92793.2756200a00.60430.60690.61190.61800.62600.63600.64700.66300.67900.69800.72000.74400.77300.8070K0.22940.46070.69790.93821.18791.44831.71892.01302.31932.64913.00583.38843.81384.2651225a00.60350.60590.61090.61720.62550.63550.64650.66220.67820.69720.71900.74300.77190.8057K0.28990.58120.88041.18581.50231.83152.17382.54462.93183.34893.79904.28264.81885.3892250a00.60270.60500.61000.61650.62500.63500.64600.66150.67750.69650.71800.74200.77050.8045K0.35750.71751.08521.46231.85312.25932.68163.13823.61594.13034.68385.28015.93986.6434275a00.60180.60400.60900.61570.62450.63450.64550.66080.67680.69580.71700.74100.76930.8033K0.43180.86391.31091.77102.24062.73163.24223.79324.37064.99265.66636.38037.17608.0264300a00.60100.60300.60800.61500.62400.6340