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History In 1679 Denis Papin developed a pressure cooker using pressurized steam. While demonstrating it the first time to the Royal Society this pressure cooker exploded. Only after Papin invented the first safety valve his pressure cooker operated safely and in 1681 he achieved a patent on this design. Denis Papin 1647-1712 is an Inventor of Ludwig Becker 1867 up to 1977 Denis Papin steam digester (1679) ARI- since 1978 Series 900 TÜV approved 1982 2
Information needed to select Operating Data Type of fluid Liquid Vapour Gas Inflammable High Viscosity Toxic Risk to the environment Operating pressure of fluid Set pressure of safety valve Operating Temperature of fluid Capacity [kg/h]; [m3/h] or [Nm3/h] Back pressure Type of Safety Valve Type of connection Type of material Type of operation (if available) Calculation myvalve 3
Selection criteria for safety valves Type of Fluid Safety valve execution Liquid Toxic, inflammable Saturated Steam Neutral Gas Heat Transfer Oil, Fluid with solids, crystallising fluids, chemicals Closed bonnet, closed lifting device or gastight cap Closed bonnet, gastight cap or closed lifting device + stainless steel bellow Open bonnet, open lifting device or Closed Bonnet, open lifting device Open bonnet, open lifting device or Closed Bonnet, open or closed lifting device Closed bonnet, closed lifting device or Closed bonnet, gastight cap could be fitted with: stainless steel bellow, maybe heating jacket and/or rupture disc upstream of the safety valve Always check suitability of marterial and design for the application! 4
Type of Safety Valve Safety valves Direct loaded Safety valves Pilot operated Safety valves European-Standard SAFE ASME-Standard REYCO 5
Type of Safety Valve European-Standard ASME-Standard SAFE SAFE-TC SAFE-P SAFE-TCP ARI-REYCO R-Series ARI-REYCO RL40/41-Series ARI-REYCO RL14 Series DIN EN 4126-1, PED97/23EC, AD 2000-A2, TRD421/721, EN12828 ASME Sec. VIII, API526 6
Opening characteristic Direct loaded Opening characteristic Full lift safety valve rapid opening Standard safety valve almost opening steadily, but not absolute linear Set pressure definition: Initial audible discharge 18. January 2016, Andreas Stall ARI - SAFE 7
ARI - are direct loaded F S =Spring force F D =A x P Force underneath the disc A direct loaded safety valve is a valve, in which the opening force underneath the valve disc is opposed by a closing force such as a spring. If the disc force F D is higher than the spring force F S, the Safety relief valve will properly relieve. A=Seat area P=System pressure Force = Seat area x System pressure Set Pressure occurs when F D = F S 18. January 2016, Andreas Stall ARI - SAFE 8
Opening characteristic Full lift safety valve A full lift safety valve is a valve which, after commencement of lift, opens rapidly within a 5% pressure rise up to the full lift as limited by the design. The amount of lift up to the rapid opening (proportional range) shall not be more than 20% of the total lift. Standard safety valve A standard safety valve is a valve which gradually opens until it reaches the degree of lift necessary for the mass flow to be discharged within a pressure rise of not more than 10%. No further requirements are made for the opening characteristics. 9
Characteristic: Full lift safety valve Type approved acc. EN ISO 4126-1 and TRD 421, TRD 721 / AD2000-A2 c = Overpressure: Acc. DIN/TRD max. 5% 1 s = Blow down Steam and gas: Max. 10% 1 or 0,3bar (whichever is greater) 1) Acc. EN 4126-1 only 10% overpressure and max. 15% blow down for steam and gas 10
Characteristic: Standard safety valve Type approved acc. EN ISO 4126-1 and TRD 421, TRD 721 / AD2000-A2 c = Overpressure: Acc. DIN/TRD max. 10% 1 or 0,1bar (whichever is greater) s = Blow down Steam and gas: Max. 10% 1 or 0,3bar (whichever is greater) Liquid : Max.20% or 0,6bar (whichever is greater) 1) Acc. EN 4126-1 only 10% overpressure and max. 15% blow down for steam and gas 11
Characteristic: EN- Type approved acc. EN ISO 4126-1, TRD 421, TRD 721 and AD2000-A2 Capacity AGFW 505 Pressure 12
Selection criteria for safety valves Large capacity Rapid pressure rise Series 901 912 Feature: DN outlet = DN inlet +2 x DN e.g. DN inlet =25, DN outlet =40 Small capacity Slow pressure rise Series 921 924 Feature: DN outlet = DN inlett z.b. DN outlet =25, DN inlet =25 18. January 2016, Andreas Stall ARI - SAFE 13
Capacity comparison 3000 Example: Air, 10 bar, DN 25 2500 2400 Capacity (Nm3/h) 2000 1500 1000 Full Lift BR 900 Standard BR 920 1560 Full Lift BR 940 Standard BR 950 Standard BR 960 500 491 240 277 0 Series 900 920 940 950 960 14
Closed lifting device Closed bonnet Gastight cap Closed bonnet Open lifting device Open bonnet Open lifting device Closed bonnet PED, Fluid group 1 with stainless steel bellow PED, Fluid group 1 PED, Fluid group 2 PED, Fluid group 2 15
SAFE, Series 900 Fig. 903 -Open lifting device -Closed bonnet Fig. 904 -Open lifting device -Closed bonnet Fig. 901 -Closed lifting device -Closed bonnet Fig. 911 -Gastight cap -Closed bonnet Fig. 902 -Open lifting device -Open bonnet Fig. 912 -Open lifting device -Closed bonnet -Heating systems -EPDM-Bellow -EPDM-Disc -Low pressure steam -Heating systems -EPDM-Bellow 16
SAFE, Series 940 Fig. 945 -Open lifting device -Closed bonnet Fig. 946 -Open lifting device -Closed bonnet Fig. 941 -Closed lifting device -Closed bonnet Fig. 943 -Gastight cap -Closed bonnet Fig. 942 -Open lifting device -Closed bonnet -Heating systems -EPDM-Bellow -EPDM-Disc -Low pressure steam -Heating systems -EPDM-Bellow 17
Stainless steel bellow Must always be vented. If the vent bore is closed with a plug or pressure gauge, then the valve is not balanced. Benefit: Compensate superimposed and built up back pressure (e.g. long outlet piping) More safe, because additionally with balanced piston Avoid spring and guide corrosion (chemicals) For toxic and inflammable media Without bellow <10% 18
30 Working pressure difference 10% up to 15% 25 Differential pressure % 20 15 10 5 1 2 3 4 5 6 7 8 9 10 20 30 40 Set pressure P bar(ü) Recommended working pressure difference: 10% up to 15% Sample: 10bar System, 10/0,85=11,8bar Set pressure Pressure reducing station (PREDU) Working pressure difference 20% up to 25% Sample: 10bar down stream, 10/0,75 = 13,3bar 18. January 2016, Andreas Stall ARI - SAFE 19
Information needed to select Operating Data Type of fluid Liquid Vapour > Saturated Steam Gas Inflammable High Viscosity Toxic Risk to the environment Operating pressure of fluid > 10 barg Set pressure of safety valve >11.5 barg Operating Temperature of fluid > 184.1 C Capacity [kg/h]; [m3/h] or [Nm3/h] > 1000 kg/h Back pressure > no Type of Safety Valve Type of connection > Flange Type of material > EN-JS1049 (nodular iron) Type of operation (if available) > Steam Boiler Nominal Pressure (PN) > PN16 or higher Calculation myvalve 20
Calculation ARI-myValve 21
Calculation ARI-myValve 22
Calculation ARI-myValve 23
Calculation ARI-myValve 24
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