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调节阀计算口径与Cv值
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调节阀计算口径与Cv值

决定调节阀口径应根据已知的流体条件,计算出必要的Cv值,然后再根据调节阀的额定Cv值,选取合适的调节阀口径。

YI、 CvZHIJISUANGONGSHI

Cv值是用来表示调节阀贵州快3的英制单位流量系数.其定义是:阀处于全开状态,两端压差为1磅/英寸2(7KPa)的条件下,60℃F(+15.6℃)的清水,每分钟通过阀的美加仑数。

调节阀计算_1

SHIZHONG

贵州快3Q=ZUIDALIULIANG gpm(MEIJIALUN/FEN) Q=ZUIDALIULIANG m3/h

贵州快3G=BIZHONG(SHUI=1) G=BIZHONG(SHUI=1)

P1=JINKOUYALI Psia(ZUIDALIULIANGSHI) P1=JINKOUYALI kgf/cm2(ZUIDALIULIANGSHI)

P2=CHUKOUYALI Psia(ZUIDALIULIANGSHI) P2=CHUKOUYALI kgf/cm2(ZUIDALIULIANGSHI)

P=P1-P2

ZHU:SHANGSHUGONGSHIZHISHIYONGYULIUTILIUDONGCHENGWENLIUZHUANGTAI,HUOLEINUOSHUDADECHANGHE,LIUTIJIEJINCENGLIUHUOLEINUOSHUJIAOXIAODECHANGHE,SHANGSHUGONGSHIBIXUJINXINGZHANDUXIUZHENG。ZHANDUXIUZHENGYAOANZHANDUXIUZHENGQUXIAN(LEINUOSHURDESHICEXISHUZHI)JINXINGXIUZHENG。

ER、BIAOSHIDIAOJIEFALIULIANGXISHUDEQITAFUHAOJIDINGYI

C——工程单位制(MKS制)的流量系数,在我国长期使用。其定义为温度5-40℃的水,在1kgf/cm2(0.1MPa)压降下,一小时流过调节阀的立方米数.

Kv——GUOJIDANWEIZHI(SIZHI)DELIULIANGXISHU,QIDINGYIWEI:WENDU5-40℃DESHUI,ZAI105PaYAJIANGXIA,MEIXIAOSHILIUGUODIAOJIEFADELIFANGMISHU。

ZHU:1.C、Cv、KvZHIJIANDEGUANXIWEI:

Cv=1.17C

Kv=1.01C

2.我国调节阀流量系数将由C系数变为Kv系数。

贵州快33.IECTUIJIANGONGSHIZHONGDEFUHAOCSHIZUOWEIGEZHONGYUNSUANDANWEIDELIULIANGXISHUDETONGYONGFUHAO,BUTONGYUNSUANDANWEIJISUANCHUDELIULIANGXISHU,YONGGONGSHIZHONGDESHUZICHANGSHUNiLAIQUBIE。YINCI,WUYUWOGUOZHANGQISHIYONGDECZHIHUNXIAO。

SAN、ZHANDUXIUZHENG

贵州快3YETIZHANDUDAYU100SSU(SAIBOTEMIAO),HUOZHEDAYU20CST(LISI),JISUANSUOYAOQIUDECvZHIYINGANXIALIECIXUJINXINGZHANDUXIUZHENG。

1.BUKAOLVZHANDUYINGXIANG,YONGGONGSHI(1)HUO(1')QIUCHUCv。

贵州快32.YONGGONGSHI(A)HE(B)HUOZHEYONGGONGSHI(A')HE(B'),QIUCHUXISHUR。

3.CONGZHANDUXIUZHENGQUXIANSHANG,QIUCHUXISHURXIANGDUIYINGDECvDEXIUZHENGXISHU。

4.YONGZHEIGEXIUZHENGXISHUCHENGYIDIYIBUQIUCHUDECv。

5.RANHOU,CONGCvZHIYILANBIAOSHANG,XUANQUHESHIDEDIAOJIEFAKOUJING。

SI、XISHURDEJISUANGONGSHI

调节阀计算_2

SHIZHONG

贵州快3Q=ZUIDALIULIANG gpm Q=ZUIDALIULIANG m3/h

Mcs=JINKOUWENDUXIAYETIYUNDONGZHANDUXISHUcst

Cv=WUXIUZHENGGUODECv

Mssu=JINKOUWENDUXIAYETIZHANDUSSU(SAIBOTEMIAO)

BEIZHU:YETIZHANDU≥200SSU,SHIYONGGONGSHI(B)HUO(B')JISUAN,ZHANDUXIAOYU200SSU,QINGBASSUZHANDUDANWEIHUANSUANCHENGcstZHANDUDANWEI,ZAIYONGGONGSHI(A)HUO(A')JISUAN。

WU、SHANZHENGXIUZHENG

热力学认为:当饱和温度的热水或者接近饱和温度的热水,流经调节阀节流口压力会降低,调节阀贵州快3出口处流出的水中可能会有水蒸气。在这流动条件下,液体流动的基本定律就不再是正确的。所以,计算调节阀口径的传统方法也就不适用。

贵州快3ZAIZHEIZHONGQINGKUANGXIA,YAOQIUCHUSUOYAOQIUDECvZHI,YINGANXIALIEBUZHOUJINXING。

贵州快3(1)△T<2.8 ℃(5°F) △Pc=0.06 ×P1......(C)

△T>2.8 ℃(5°F) △Pc=0.9(P1-Ps)......(D)

SHIZHONG:

△T=ZAIJINKOUYALIXIADEYETIBAOHEWENDUYUJINKOUWENDUZHICHA

△Pc=JISUANLIULIANGYONGDEYUNXUYACHA (kgf/cm2)

P1=JINKOUJUEDUIYALI(kgf/cm2 abs)

Ps=JINKOUWENDUXIAYETIDEJUEDUIBAOHEYALI (kgf/cm2 abs)

贵州快3(2)ZHIYOUDANGGONGSHI(C)HUO(D)JISUANCHUDE△PcXIAOYUDIAOJIEFASHANGDESHIJIYACHA△PSHI,GONGSHI(1)HUO(1')BIXUYONG△Pc,ERBUZHUNYONG△P。

调节阀计算_3

贵州快3LIU、CHUSHUIYIWAIDEQITAYETI

DUIYUSHUIYIWAIDEQITAYETI,SUIRANYEKEXIANGSHUIYIYANGCAIYONG,“LINJIEYACHAFA”HUO“YETIQITIHUNHEBIZHONGFA”DENG,DANZHEILIANGZHONGFANGFABIXUYIZHIYETIDEBAOHEYALIHUOLINJIEYALISHUJU。MUQIAN,JINJUXIANYUYIZHIBAOHEYALIHUOLINJIEYALIDEJIZHONGYETICAICAIYONGZHEILIANGZHONGFANGFAJISUAN,QITAYETIYIBANBUYONGZHEILIANGZHONGFANGFA。YIBANDEJISUANFANGFASHIQIUCHUSHANZHENGDEBILV。RANHOUFENBIEJISUANCHUYETIHEQITIDECvZHI,TAMENDEZHIHEZUOWEIJISUANJIEGUO。SHANZHENGDEBILV:

调节阀计算_4

贵州快3SHIZHONG:i1—JINKOU(T1)XIADEHAN(Kcal/kg)

i2—CHUKOUYALIP2DEBAOHEWENDU(T2)XIADEHAN(Kca1/kg)

贵州快3r2—CHUKOUYALIP2DEBAOHESHIDU(T2)XIADEQIANRE(Kca1/kg)

Cp—调节阀计算_5的液体比热,(Kca1/kg)

调节阀计算_6

QI、QITIJISUANGONGSHI

贵州快3QITIJISUANGONGSHISHIBAYETIJISUANGONGSHIDEBIZHONG,JINGGUOHUANSUANHOUDECHUDE。ZHEIGEBIZHONGSHIQUJINKOUYICEZHUANGTAIXIADEBIZHONGNI,HAISHIQUCHUKOUYICEZHUANGTAIXIADEBIZHONGNI,HAISHIQUQILIANGZHEPINGJUNZHINISHIYANZHENGMING。QUPINGJUNZHIDEJISUANJIEGUOBIJIAOJIEJINSHIYANSHUZHI。SUOYIZUIJINPUTONGCAIYONGBIZHONGPINGJUNZHILAIJISUANCvZHI。

贵州快3LINGWAI,QITIZAI△P≥P1/2ZHUANGTAISHI,QITIDELIUSUDADAOYINSU,LIULIANGHUIDADAOBAOHEZHUANGTAI。YACHAZAIZENGDA,LIULIANGYEBUHUIZENGJIALE。YINCIYINGFEN△P<P1/2HE△P≥P2/2LIANGZHONGQINGKUANGJIAYITAOLUN。

1.△P<P1/2 2.△P≥P1/2SHI

Cv=调节阀计算_7 Cv=调节阀计算_8

贵州快3Q:ZUIDALIULIANG(ZAI760mmHgabs,15.6℃TIAOJIANXIA)

G:BIZHONG(KONGQI=1)

T:LIUTIWENDU(℃ )

P1:JINKOUJUEDUIYALI(kgf/cm2abs)

贵州快3P2:CHUKOUJUEDUIYALI(kgf/cm2abs)

△P=P1-P2(kgf/cm2abs)

贵州快31.△P<P1/2 2.△P≥P1/2SHI

Cv=调节阀计算_9 Cv=调节阀计算_10

贵州快3SHIZHONG:Q:ZUIDALIULIANG(ft3/h)(ZAI14.7psi abs, 60FTIAOJIANXIA)

G: BIZHONG(KONGQI=1)

T:LIUTIWENDU(°F )

P1:JINKOUJUEDUIYALI(1bs/in2abs)

P2:CHUKOUJUEDUIYALI(1bs/in2abs)

△P=P1-P2

(ZHU:P1HEP2WEIZUIDALIULIANGSHIDEYALI)

BA、SHUIZHENGQIJISUANGONGSHI

贵州快3TAYUQITIYIYANG,YEYINGFENLIANGZHONGQINGKUANGJIAYITAOLUN。

1.△P<P1/2 Cv=调节阀计算_11 Cv=调节阀计算_12

2.△P≥P1/2 Cv≥调节阀计算_13 Cv≥调节阀计算_14

贵州快3SHIZHONG:W:ZUIDALIULIANG(1bs/hr) W:ZUIDALIULIANG(kg/hr)

P1*: JINKOUJUEDUIYALI(1bs/in2abs) P1*:JINKOUJUEDUIYALI(kgf/cm2abs)

P2*: JINKOUJUEDUIYALI(1bs/in2abs) P2*::CHUKOUJUEDUIYALI(kgf/cm2abs)

贵州快3K: 1+(0.0007×GUOREWENDU°F) K::1+(0.0013×GUOREWENDU℃)

△P=P1-P2(1bs/in2) △P=P1-P2(kgf/cm2)

(ZHU:P1HEP2WEIZUIDALIULIANGSHIDEYALI)

JIU、QITAZHENGQIJISUANGONGSHI

QITAZHENGQIDEJISUANGONGSHI,TONGSHUIZHENGQIDEJISUAN,KEDEDAO

Cv=调节阀计算_15 Cv=调节阀计算_16

贵州快3ZHU:DANGP2<P1/2SHIYINGYONGP1/2DAITI△P,V2YINGYONGP1/2XIANGDUIYINGDEZHI。

贵州快3SHIZHONG:W:ZUIDALIULIANG(1bs/hr) W:ZUIDALIULIANG(kg/hr)

V1:ZAIJINKOUYALIP1XIAZHENGQIBIRONG(ft3/1bs at P1) V1:ZAIJINKOUYALIP1XIAZHENGQIBIRONG(cm3/gr at P1)

V2:ZAICHUKOUYALIP2XIAZHENGQIBIRONG(ft3/1bs at P2) V2:ZAICHUKOUYALIP2XIAZHENGQIBIRONG(cm3/gr at P2)

P1*:JINKOUJUEDUIYALI(1bs/in2abs) P1*:JINKOUJUEDUIYALI(Kgf/cm2 abs)

P2*:JINKOUJUEDUIYALI(1bs/in2abs) P2*:CHUKOUJUEDUIYALI(kgf/cm2 abs)

贵州快3△P=P1-P2(1bs/in2) △P=P1-P2(kgf/cm2)

(ZHU:P1HEP2WEIZUIDALIULIANGSHIDEYALI)

SHI、GONGCHENGTONGJINGDEXUANZE

调节阀贵州快3公称通径选择,是由最大Cv值、可调范围,以及调节阀有足够的调节余量,这几个因素来决定的。 最大Cv值和最小Cv值是分别在最大流量和最小流量条件计算出的二个数值。

1.ZUIDACvZHI

鉴于额定Cv值有±20%、-10%的调节误差,建议等百分比阀在90-95%开度内的值作为最大Cv值,线性调节阀在80~90%开度内的值作为最大Cv值。

2.CHANGYONGCvZHI

贵州快3CHANGZAIDIKAIDUXIAGONGZUO,FAXINYIYUMOSUN,ZAICONGKONGZHIXINGNENGSHANGKAOLV,XIWANGFAZAI50~80%KAIDUFANWEIGONGZUO。

3.ZUIXIAOCvZHI

贵州快3FADEZUIXIAOCvZHIYINGZAIGUYOUDEKEDIAOFANWEIZHINEI,SHIJISHANGDADUOSHUDIAOJIEFAKONGZHILIUTISHI,KAIDUBIANHUA、FASHANGYACHAYEXIANGYINGBIANHUA。KAIDUYULIULIANGZHIJIANDEGUDINGLIULIANGTEXING,BIANCHENGLESHIJIDELIULIANGTEXING,KEDIAOFANWEIYEBIANXIAOLE。FADADAOZUIXIAOCvZHISHI,XIWANGFAZAI10~20%KAIDUSHANGGONGZUO,RUGUOYAOSHIFAZAIGENGXIAODEKAIDUFANWEINEIGONGZUO,YINGXUANZEKEDIAOFANWEIJIAOXIAODEDIAOJIEFA,HUOZHEGAIYONGYITAIDA,YITAIXIAODEQIEHUANFA,YONGZHEIERTAIFAFENCHENGKONGZHILIULIANG。

SHIYI、SUOXIAOFAKONG

单座阀、双座阀及角阀等调节阀,同一个公称通径,设计了几组不同的缩小阀孔,它的流量系数比原来的额定值小一档或小二档,笼式阀只要更换套筒就可以做到这一点,蝶阀、三通阀、隔膜阀等没有缩小阀孔的规格。

缩小阀孔的调节阀用于下列场合:

(1)CONGJIXIEQIANGDUSHANGKAOLV,(GUANDAOYINGYONGYINQI)BIXUXUANYONGDACHICUNDEFATI。

(2)FADELIULIANGXISHUJINHOUYOUKENENGJIADA。

贵州快3(3)JIANGDIDAYACHACHANSHENGDEZAOYIN,HUOZHEZENGJIAFATIGEBUFENDEQIANGDU。

(4)JIANSUOGUANCHENGBENTAIGAO

(5)FATISHOUSHANZHENGLIUTIHEGAOYACHALIUTI、QISHIPOHUAISHI,ZENGDAXIALIUCELIUCHUJIEMIANJI,KEJIANQINGQISHIPOHUAI。

调节阀计算_17


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