RESEARCH OF A CONTROL VALVE CHARACTERISTICS TEST

Transcription

1 Journa of Thortica and Appid Information Tchnoogy 10 th May Vo. 51 No JATIT & LLS. A rights rsrvd. RESEARCH OF A CONTROL VALVE CHARACTERISTICS TEST 1 YUDONG XIE, 2 YANJUN LIU, 3 YONG WANG 1,2,3 Ky Laboratory of High-fficincy and Can Mchanica Manufactur at Schoo of Mchanica Enginring, Shandong Univrsity, Ministry of Education, Jinan, Shandong, China E-mai: 1 yudong_2177@163.com, 2 corrsponding author yj111@sdu.du.cn, 3 mywang@sdu.du.cn ABSTRACT Contro vavs ar commony found in modrn procss pants. Th contro vav riabiity is critica to th contro quaity and safty of a pant. Whthr a contro vav mts th chang of th contro rquirmnt dpnds on its rspons charactristics. To obtain th charactristics of th contro vav, an xprimnt tst systm is dvopd to assss th prformancs of th contro vav, th graphica dscription for th prformancs of th contro vav is proposd, and th tst mthod is prsntd. Kywords: Tst Tchnoogy, Contro Vav, Procss Contro, Rspons Charactristics 1. INTRODUCTION Th markt dmands for highr quaity products hav incrasd th nd for rducd procss variation [1]-[3]. On factor in th quaity of th fina nd product is th improvmnt of th contro oop prformanc. A critica componnt in th oop is th contro vav [4]-[5]. Whthr th contro vav mts th chang of th contro rquirmnt dpnds on its rspons prformancs [6]-[7]. Th static prformanc indxs of th contro vav mainy incud intrinsic rror, rpatabiity rror, rproducibiity rror, ratd trav dviation, dad band, start rror, stop rror, tc. Th dynamic prformanc indxs usuay contain stprspons ris tim, stp-rspons pak tim, stprspons rguating tim, stp-rspons ovrshoots, tc. In ordr to gt th static and dynamic charactristics of th contro vav, w nd to buid a tst systm and stabish th tst mthod. In this papr, sction 2 prsnts th dsign of th tst systm which is usd to obtain th prformancs of th contro vav. Sction 3 proposs th graphica dscription and th tst mthod for th prformancs of th contro vav. Sction 4 givs concusions to th who papr. 2. DESIGN OF THE TEST SYSTEM Th schmatic diagram of th prformanc tst systm of th contro vav is shown in Fig. 1. Th contror is a computr contror. Th signa of prssur or fow masurd using th prssur or fow mtr is compard with th signa of th dsird prssur or fow by th contror. Th contror output accordingy adjusts th opning/cosing actuator of th contro vav in ordr to maintain th actua prssur or fow cos to th dsird prssur or fow. Th communication btwn th PC and th priphras is raizd by th PCI-6238 data acquisition card which is producd by th Nationa Instrumnts Company of th Unitd Stats. Th main tchnica paramtrs of PCI-6238 ar as foows: (1) 60V Isoatd (Anaog Currnt: 8 Anaog Inputs, 2 Anaog Outputs, Digita 30V: 6 Inputs, 4 Sourcing Outputs). (2) For th anaog input, th samping rats is 250 ks/s, th rsoution is 16 bits, th maximum input currnt is in th rang of -20mA ~ + 20mA, prcision scop is 18.8 μa, and th rang of snsitivity is 0.24μA. (3) For th anaog output, th updat rat is 500 ks/s, th rsoution is 16 bits, th maximum currnt rang is in th rang of 0-20mA, and th prcision scop is 52.3μA. (4) For th digita channs, th input votag is in th rang of 0-30 V, th output votag is in th rang of 0-30 V. Th oprationa intrfac of th softwar contro systm is shown in Fig

2 Journa of Thortica and Appid Information Tchnoogy 10 th May Vo. 51 No JATIT & LLS. A rights rsrvd. contro vav thrott rguator pip fow snsor pip prssur snsor pip fang fang pip prssur snsor fuid position transducr actuator wiring card computr contro systm data acquisition card PCI-6238 PC contror Fig. 1 Schmatic Diagram Of Th Prformanc Tst Systm Fig. 2 Oprationa Intrfac Of Th Softwar Contro Systm 81

3 Journa of Thortica and Appid Information Tchnoogy 10 th May Vo. 51 No JATIT & LLS. A rights rsrvd. ratd trav maxima positiv dviation cut-off curv start-point positiv dviation start-point minus dviation intrinsic-rror uppr imit hystrsis rror spcifid charactristic curv maxima minus dviation owr imit uppr imit vau input/(%) Fig. 3 Graphic Dscription For Th Static Prformanc trmina positiv dviation ratd trav dviation trmina minus dviation intrinsic-rror owr imit opning curv ovr uppr imit vau 3. TEST METHOD According to th rvant tst standard, th contro vav is in no-oad condition for th static prformanc tst. In th tst, w shoud input th sowy changing signa succssivy in th positiv dirction and th ngativ dirction, so as to mak th actuator of th contro vav oprat continuousy and smoothy in th who trav. Whn tst th trav, w shoud rgard th position whr th cor of th contro vav is totay cos as th tst rfrnc. Fig.3 shows th graphic dscription for th static prformanc of th contro vav [8]. Aftr th tst, w can gt th static prformanc indxs of th contro vav according to th foowing mthod. (1) intrinsic rror In th spcifid rfrnc conditions, th cacuation formua of th intrinsic rror can b writtn as t s in (1) whr t dnots th tst trav vau of th tst point, s xprsss th spcifid trav vau of th tst point, and is th ratd trav of th contro vav. (2) rpatabiity rror Th cacuation formua of rpatabiity rror can b dscribd by i j r (2 ) whr i is th maximum trav masurmnt of th tst point, and j dnots th minimum trav masurmnt of th tst point (in th condition of tst input signas in th sam dirction for many tims). (3) rproducibiity rror Th rproducibiity rror can b xprssd as m n rc (3) whr m is th maximum trav masurmnt of th tst point with vav opn signas, and n xprsss th minimum trav masurmnt of th tst point with vav cos signas. (4) start rror stop rror Th start rror and th stop rror can b writtn, rspctivy, as d sa (4) g so (5) 82

4 Journa of Thortica and Appid Information Tchnoogy 10 th May Vo. 51 No JATIT & LLS. A rights rsrvd. Fig. 4 Stp Rspons whr sa xprsss th start rror, so is th stop rror, d is th trav masurmnt whn th input signa is in th owr imit, and g is th trav masurmnt whi th input signa is in th uppr imit. (5) ratd trav rror Th ratd trav rror can b dscribd by a ra (6) whr a is th trav masurmnt whn th input signa is in th ovr uppr imit. (6) hystrsis rror Th hystrsis rror can b writtn as b c hy (7) whr b dnots th trav masurmnt of th tst point with th vav opn signa, and c is th trav masurmnt of th tst point with vav cos signa. As shown in Fig. 4, w can obtain th dynamic charactristics through stp rspons tst. 4. CONCLUSIONS Contro vavs ar gnray prsnt whnvr fuid fow rguation is rquird. Th contro vav charactristics ar critica to th contro quaity and safty of a pant. By mans of th tst tchniqu, th charactristics of th contro vav can b obtaind. In this papr, an xprimnt tst systm is dvopd to assss th prformancs of th contro vav and th tst mthod is prsntd. ACKNOWLEDGEMENTS This work was supportd by Spcia Funds for Postdoctora Innovativ Projcts of Shandong Provinc (No ), Indpndnt Innovation Foundation of Shandong Univrsity (IIFSDU No. 2011GN045), and Ky Laboratory of Highfficincy and Can Mchanica Manufactur at Shandong Univrsity of Education Ministry. REFRENCES: [1] K. Yonzawa, R. Ogawa and K. Ogi, Fowinducd Vibration of a Stam Contro Vav, Journa of Fuids and Structurs, Vo. 35, 2012, pp [2] M.A. Mohammad and B. Huang, Compnsation of Contro Vav Stiction Through Contror Tuning, Journa of Procss Contro, Vo. 22, No. 9, 2012, pp [3] M. Pottr and M. Bacic, Dsign and Contro of Hardwar-in-th-oop Simuations for Tsting Non-rturn-vav Vibrations in Air Systms, IEEE Transactions on Contro Systms Tchnoogy, Vo. 20, No. 1, 2012, pp [4] YS. Tvrskoi, N.A. Agafonova and E.D. Marshaov, Diagnosing th Charactristics of Contro Vavs usd in Powr Unit Contro Systms, Thrma Enginring, Vo. 59, No. 2, 2012, pp [5] Y.D Xi, Y.J. Liu and Y. Wang, Prdiction Mod of Contro Vav Charactristics, 83

5 Journa of Thortica and Appid Information Tchnoogy 10 th May Vo. 51 No JATIT & LLS. A rights rsrvd. Advancd Matrias Rsarch, Vo , 2013, pp [6] D. Bottazzi, F. Franzoni and M. Miani, Mtring Charactristics of a Cosd Cntr Load-Snsing Proportiona Contro Vav, SAE Intrnationa Journa of Commrcia Vhics, Vo. 2, No. 2, 2010, pp [7] J. Ruan, R. Burton and P. Ukraintz, An Invstigation into th Charactristics of a 2D Fow Contro Vav, Amrican Socity of Mchanica Enginrs, Th Fuid Powr and Systms Tchnoogy Division, Vo. 7, 2000, pp [8] Y.Q. H, X.Z. Qiu and J. Yang: Dsign and Appication of Contro Vav, Chmica Industry Prss, Bijing of China