1、Manual on Installation of RefineryInstruments and Control SystemsiPartl-Process Instrumentation and Con入Section 1-FlowRECOMMENDED PRACTICE 550ENTRO OE INFORMAGFOURTH EDITION,MARCH 1986American Petroleum Institute1220 L Street,NorthwestWashington,D.C.20005API RP 550-PART I卡wHd.THISSTAMPED ON UPSTREAM
2、LINESIDE OF THE PLATESIZEINLET”6 mm)DIA HOLEPLATE BEFOREORIFICE HOLEIS MADESHARPSQUARE EDGESd0000530045DRECTIONOF FLOWCHAMFER ORDOWNSTREAMWHEN tTOPTIONA3nHOLNSECTIONZONTAL LINESS O0POF LINEOR L IQUIDCONTAININGVAPOR ORNONCONDENSABL ESOrifice Plate Outside Diameters to Fit ANSI Service Rated Flange Un
3、ionsCLASSNominalTABPipe Size人30060090015002500Lw3名43%4%5%55%53/4a3%43地5%6%67/e7%47%75%8%8%49%a6A6%9%10211%11/%12h61。12%12%14%13%154144153%17%17%18%612165/%1819%20h215%6119%19%20h22%61621422%225%254623h24%25%27/%60州%25%267%27229%42%30h31%3335hNOTES:1.All measurements in inchescommercially:any plale d
4、eparting from flatness along any diameter more2.The outside diameter(OD)of the orifice plate is that required to fit in-than 0.010 perinch(.25 millimeters)of dam height.(D-d)/2.shall be unacside the bolts of standard ANSI flanges.The outside diameter is equal toceptable.Surface roughness shall not e
5、xceed 50 microinches in a band atthe diameter of bolt circle minus thenominal diameter of bolt.within aleast 0.25 diameter wide around the oritice bore.manufacturing tolerance of+0 inches,-%2 inch(+0 millimeters,-.85.All seating surfaces for spiral-wound gaskets should be clean and freeof rust,burrs
6、.nicks,and so forth.Any surface not meeting the following3.For orifice plate outside diameters in flange sizes and ratings not listedolerances should be relapped:above,refer to gasket OD dimensions given under Figure 3.Table 1,Ap.(a)Roughness:Should not exceed 80 root mean square with 63 root meanpe
7、ndix Ein ANSIB16.591.Sreel Pipe Flanges and Flanged Fiisquare or better as optimum.vailable from the American Society of Mechanicl Engineers.345 East(b)Flatness:Out-of-plane tolerancesmust not exceed 0.0025 inch(0.0647th Street.New York,New York 10017.millimeter).The cumulative out-of-flatness for two mating surfaces shall4.The upstream face of the orifice plate shall be as flat as can beobtainednot exceed 0.0040 inch(0.I millimeter).Figure 1-1-Concentric Orifice Plate