贵州快3

 
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气动薄膜执行机构输出力不足的分析
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0QIANYAN

贵州快3MUQIANJINXITIANRANQIHUAGONGYOUXIANZERENGONGSINIAOSUZHUANGZHICAIYONGYIDALISINAMUANQITIGONGYILIUCHENG,ANQITITADECHULIAOYEKONGZHISHITONGGUO1TAIDIAOJIEFA(LV-09202)SHIXIANDE。LV-09202XUANYONGMasoneilanGONGSICHANPIN,ZHIXINGJIGOUWEIQIDONGBOMOFANZUOYONG38XING,FATIWEI70500XILIEJIAOFA,DIAOJIEFAWEIQIKAIFA。KONGZHIJIEZHISHINIAOSURONGYE,YIJIEJING,QIANGFUSHIXING,GONGYICAOZUOYALI14.4MPa,CAOZUOWENDU207 ℃ 。

LV-09202YU2008NIAN6YUECHUXIANKONGZHISHIDCSDIAOJIEHUILUSHUCHUWEI0,ZHIXINGJIGOUMOTOUWUSHURUQIYASHI,XIANCHANGSHIJIFAWEIKAIDUWEI25%。CHAKANGONGYICAOZUOZHIBIAO,FAQIANYALIBIANSONGQIXIANSHIWEI14.68Mpa,FAHOUYALIBIANSONGQIXIANSHIWEI1.72Mpa,FAQIANHOUCHAYA12.96Mpa。

贵州快3DANGNIAOSUZHUANGZHITINGCHE,GAOYAXITONGFENGTABAOYA,FAQIANYALIXIANSHI13.62MPa,FAHOUYALIYOUYULV-09202HOUDIANDONGFAGUANBIERZENGDA,ZHEISHIFAQIANHOUCHAYAJIANGDI。DIAOJIEHUILUSHUCHU0SHI,LV-09202FAWEIZAIDANHUANGDEFUWEIZUOYONGXIAGUANBI。

贵州快3CONGDIAOJIEFACHUXIANDEGUZHANGXIANXIANG,HUAIYIZHIXINGJIGOUSHUCHULIBUGOU,WUFAKEFUQITITANEIDEGAOYAJIEZHIZUOYONGLI,FAGUANBUDAOWEI,XIELOULIANGDA,ZAOCHENGGONGYICAOZUODANXINGJIANGDI,ZAIDIFUHEXIAWUFACAOZUO。

1 执行机构输出力不足的分析

贵州快3ZHIXINGJIGOUDESHUCHULIJIUSHIYONGYIKEFUJIEZHIFUHEDEYOUXIAOLI,ERFUHEBAOKUOBUPINGHENGLI、MIFENGJINYALI、MOCALI、ZHONGLIANGDENG,DUIYUDANZUOYONGQIDONGBOMOZHIXINGJIGOU,QILIPINGHENGGONGSHIWEI:

F=Ft+Fo+Ff+Fw贵州快3            (1)

SHIZHONG:

F——ZHIXINGJIGOUSHUCHULI;

Ft——阀芯所受的不平衡力;

Fo——调节阀全闭时,阀芯对阀座密封所需附加的紧压力。一般取相当于5kPa乘以薄膜有效面积(m2)的力;

Ff——阀杆所受摩擦力;

Fw——阀芯等活动部件重量。

正常情况下Ff很小,各种活动件重量Fw也不大,所以(1)式可简化为:

F=Ft+Fo贵州快3               (2)

从式(2)可以看出,执行机构的输出力主要是克服调节阀的不平衡力。而对于直行程的调节阀,如单座调节阀、角型阀等,当流体通过调节阀时,阀芯受到介质静压和动压的作用,会产生使阀芯上下移动的轴向力。这种轴向力影响执行机构信号与位移的关系,因此,将阀芯所受到的轴向合力称之为不平衡力,以Ft表示。

YINGXIANGDIAOJIEFABUPINGHENGLIDEYINSUHENDUO,LIRU,FADEJIEGOUXINGSHI、KOUJING、LIUTIWULIZHUANGTAI。RUGUOGONGYIJIEZHIJIDIAOJIEFADOUYIQUEDING,BUPINGHENGLIZHUYAOYUFAQIANYALIHEFAQIANHOUYACHAYOUGUAN,YEYULIUTIYUFAXINDEXIANGDUILIUXIANGYOUGUAN。

DANGLIUTILIUXIANGBUTONGSHI,FAXINSUOSHOUDEBUPINGHENGLIBINGBUXIANGTONG。DUIYUZHITONGDANZUOFA、JIAOXINGFA,CHUYULIUKAIZHUANGTAISHI,QIBUPINGHENGLIJISUANGONGSHI:

Ft=π/4*(dn2ΔP+ds2P2贵州快3)         (3)

SHIZHONG:

Ft——不平衡力,N;

dN——阀芯直径,m;

dS——阀杆直径,m;

ΔP——阀前后差压,ΔP=P1-P2,Pa;

P1——阀前压力,Pa;

P2——阀后压力,Pa。

从式(3)看出,Ft始终为正值,阀杆处于受压状态。dN、ΔP和P2越大,则不平衡力Ft越大。对于高压差、高静压,大口径的单座阀不平衡力Ft也就较大。而且,阀芯在全关位置时,不平衡力Ft最大,随着阀芯开启而逐渐变小,由于中间位置动压难以用公式表示,在计算调节阀不平衡力时,主要根据全关时来确定。

因此,调节阀在生产应用中,当执行机构输出力F小于调节阀的不平衡力Ft时,造成调节阀关不上,泄漏量大。

2 DIAOJIEFABUPINGHENGLIDEJISUAN

ZONGSHANGSUOSHU,YIJULV-09202DESHEJIGONGYITIAOJIAN、JISHUCANSHU,DUIZHIXINGJIGOUDANHUANGJINXINGCESHI,BINGHESUANLV-09202DEBUPINGHENGLIJIQIZHIXINGJIGOUDESHUCHULI。

2.1 LV-09202DEGONGYITIAOJIANJIQIJISHUCANSHU

DIAOJIEFADEGONGYITIAOJIAN:ZUIXIAOLIULIANGSHIRUKOUYALI14.90MPa,ZUIXIAOLIULIANGSHIYACHA13.34MPa;ZUIDALIULIANGSHIRUKOUYALI14.51MPa,ZUIDALIULIANGSHIYACHA12.55MPa,ZUIDAQIEDUANYACHA16.2MPa,FATIJIEZHILIUXIANGWEILIUKAI,ZHIXINGJIGOUWEIFANZUOYONG,DIAOJIEFAWEIQIKAIFA。

调节阀的技术参数:公称通径DN=152.4mm,阀芯直径dN=50.5mm,阀杆直径ds=44.5mm,执行机构型号38型,规格457.2mm,薄膜有效面积Ae=1290cm2,行程L=38.1mm,执行机构弹簧范围225~345kPa,气源压力400kPa。

DANHUANGSHUJU:WAIDANHUANGYOUXIAOQUANSHU6.5QUAN,ZONGQUANSHU8QUAN,GANGSIZHIJING32mm,ZIYOUGAODU510mm。NEIDANHUANGYOUXIAOQUANSHU11QUAN,ZONGQUANSHU12.5QUAN,GANGSIZHIJING22mm,ZIYOUGAODU520mm。

2.2 LV09202ZHIXINGJIGOUDANHUANGCESHIBAOGAO

DIAOJIEFAZHIXINGJIGOUDESHUCHULIYUQIDANHUANGDEFANZUOYONGLIXIANGDENG,TONGGUOZHIXINGJIGOUSHUCHULIJISUANGONGSHI(4)JIKEQIUDEDANHUANGLIDEFANWEI。

贵州快3F=Pr*Ae                (4)

SHIZHONG:

PrZHIXINGJIGOUDANHUANGFANWEI,Pa;

Ae膜片的有效面积,m2

JIANGZHIXINGJIGOUDEDANHUANGFANWEI0.225~0.345MPa,DAIRUSHI(4)FENBIEQIUDEDANHUANGDEYUJINLI29025N;QUANKAISHIDEDANHUANGLI44505N。

按照F1、F2对组合簧进行变形量的测试:按F1测出组合簧的变形高度410mm,按F2测出组合簧的变形高度350mm,组合簧的变形量60mm。由实测的组合簧变形量,对照执行机构的行程,可以看出组合簧与行程的偏差有21.9mm,这说明LV-09202执行机构弹簧发生了变化,导致这种变化的原因一种可能是弹簧本身所产生的疲劳失效,另一种可能是弹簧在设计时的计算偏差。

2.3 LV-09202BUPINGHENGLIJIQIZHIXINGJIGOUSHUCHULIDEJISUAN

1)ZHIXINGJIGOUDEZUIDASHUCHULIDEJISUAN:

FMax贵州快3=Pr*Ae=29025N

2)DIAOJIEFABUPINGHENGLIHEFAZUODEYAJINLIDEJISUAN:FAQIANYALI14.9MPa;FAHOUYALI0.0156MPa;QIUCHU:

Ft=π/4*(dn2*ΔPMax+dg2*P2)=29146N

阀座的压紧力,硬密封阀座为645N;Ft与F0的和为29791N。从上述结果可知满足执行机构输出的条件:

FMax=F输出力≥Ft+Fo

LV-09202的执行机构的输出力FMax=F输出力≥Ft+F0贵州快3,可知未能满足执行机构输出的条件,所以LV-09202关不死,泄漏量大。

3 JIEJUEFANGAN

贵州快3CONGZHIXINGJIGOUSHUCHULIGONGSHI(4)KEZHI,TONGGUOJIADADANHUANGDEYUJINLI,KEYIZENGJIAZHIXINGJIGOUDESHUCHULI。TONGCHANGZENGDADANHUANGYUJINLIKECONGLIANGGEFANGMIANKAOLV:DIAOZHENGZHIXINGJIGOUDEDANHUANGYUJINLILUOMU;ZENGZHANGFAGANZHANGDU。YOUYULV-09202XUANYONGDAIDINGZHUANGSHOULUNDEZHIXINGJIGOU,XIANZHILEZHIXINGJIGOUDANHUANGYUJINLIDEDAFANWEIDIAOZHENG,ZHEIJIZENGJIAZHIXINGJIGOUSHUCHULIDAILAILEYIDINGDENANDU。

因此,针对LV-09202的情况,采用更换弹簧以增大执行机构的输出力。弹簧选用计算办法就是将不平衡力Ft乘一个系数,系数取1.1,以确保执行机构的输出力。在大压差的情况下,一般要计算阀芯所受的不平衡力和执行机构的输出力,使其满足:

F输出力≥1.1(Ft+Fo)

JISUANLV-09202DESHUCHULIYINGWEI:

F输出力=1.1(Ft+Fo)=32770N

贵州快3HUANSUANXIANGYINGDEZHIXINGJIGOUQIDONGYALIWEI:0.254MPa。RUOQIYUANQIDONGFENGYAQU0.254MPaPIANDA,JIANGYINGXIANGBOMOMOPIANDESHIYONGSHOUMING,GUJIANGXISHUQUWEI1.05。

F输出力=1.05(Ft+Fo)=31000N

DIAOJIEFAQIDONGFENGYAGAIWEI0.24MPa。

2008NIAN8YUEDINGZUOXINDANHUANG,BINGGENJUZHIXINGJIGOUJIEGOUJINXINGLEZAIXIANGENGHUANDANHUANG,YONGBIAOZHUNYIQIDIAOZHENGZHIXINGJIGOUDEQIDONGFENGYAWEI0.24MPa。

GENGHUANDANHUANGHOU,LV-09202DEZHIXINGJIGOUCHANSHENGLEZUGOUDESHUCHULI,NENGGOUKEFUQISUOSHOUDEBUPINGHENGLI,BAOZHENGLEDIAOJIEFADEMIFENGHEKAIDU,MANZULEGONGYISHENGCHANDEXUQIU,ZAIYIDINGCHENGDUSHANGTIGAOLESHENGCHANLIANG。







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