API - Leser

Type 526Type 526Determination of coefficent of dischargein case of lift restriction or back pressureDiagram for evaluation of ratio of lift / flow diameter (h/d 0 )in reference to the coefficient of discharge (K dr /α w )h = Lift [mm]d 0 = Flow diameter [mm] of selected safetyvalve, refer to table article numbersh/d 0 = Ratio of lift / flow diameterp a0 = Back pressure [bar a ]p 0 = Set pressure [bar a ]p a0/p 0 = Ratio of back pressure / set pressureK dr = Coefficient of dischargeacc. to DIN EN ISO 4126-1α w = Coefficient of dischargeacc. to AD 2000-Merkblatt A2K b = Back pressure correction factoracc. to API 520 topic 3.3Steam and GasesLiquids0,90K dr = α w = f (h/d 0 )0,70K dr = α w = f (h/d 0 )0,800,70Orifice E-K "S/G"0,60Orifice E-K "L"0,600,50Coefficient of discharge K dr / αw0,50Orifice L-T "S/G"Orifice D "S/G"0,400,300,200,100,000,00 0,05 0,10 0,15 0,20 0,25 0,30 0,350,1070,28 0,32Ratio of lift / flow diameter h / d 0Coefficient of discharge K dr / αw0,40Orifice L-T "L"Orifice D "L"0,300,200,100,000,00 0,05 0,10 0,15 0,20 0,25 0,30 0,350,1070,28 0,32Ratio of lift / flow diameter h / d 0Diagram for evaluation of coefficient of discharge (K dr /α w ) or K bin reference to the ratio of back pressure / set pressure (p a0 /p 0 )Orifice DOrifice E-T0,50K dr = α w = f (p a0 /p 0 ) and K b = f (p a0 /p 0 )dr 00,90K dr = α w = f (p a0 /p 0 ) and K b = f (p a0 /p 0 )dr 0Coefficient of discharge K dr / αwOrifice D "S/G"0,400,300,200,100,000,20 0,30 0,40 0,50 0,60Ratio of back pressure / set pressure p a0 / p 00,701,000,900,800,700,600,500,400,300,200,100,000,800,777Back pressure correction factor K bCoefficient of discharge K dr / αw0,800,70Orifice E-T "S/G"1,000,900,800,600,500,400,700,600,500,300,400,300,200,200,100,100,000,000,20 0,30 0,40 0,50 0,60 0,70 0,800,777Ratio of back pressure / set pressure p a0 / p 0Back pressure correction factor K bHow to use please refer to page 00/0801/92 LWN 480.01-E