Datasheet Pressure Reducing Valves V78/V8/V8 Advantages - No auxiliary energy is required to operate the valve - Small standard tolerances due to the large control surface and the spiral spring - Can also be adjusted under working pressure - Largely maintenance-free and installable in any position - All parts which come into contact with the medium made of highly resistant plastics - Streamlined Housingshape enables high flow rates - V8 / V8 standard version with manometer Dimensions Type V8: d5dn0-d0dn00, 3/8" - " Type V8: d6dn0-d50dn0, 3/8" - /" Type V78: d6dn0-d50dn0, 3/8" - /" Materials Valve Body Type V8: PP, EPDM Type V8: PP, EPDM Type V78: PP, EPDM Connectors Solvent cement spigot DIN/ISO Fusion spigot DIN/ISO Springs Type V8: Belleville spring Type V8: Spiral spring Type V78: Spiral spring Sealing Materials Type V8: EPDM, EPDM-PTFE-coated Type V8: EPDM, FPM Type V78: EPDM, EPDM-PTFE-coated Nominal pressure PN in bar Type V8 DN0-DN50: 0.5-0, DN65 - DN80: 0.5-6, DN 00: 0.5- Type V8: 0.5-0 Type V78: 0.5-0 Approvals Function and design On the valve outlet, the pressure (P) acts on the piston (shown in red) which is linked to the spring (orange). The spring preload is adjustable by a screw. Thus it is possible to reach equilibrium of forces (adjusted outlet pressure). If the outlet pressure exceeds the preset value, the piston is lifted against the spring force. Due to this the valve closes and the outlet pressure decreases. If the outlet pressure is decreasing below the preset value the piston is forced downwards by the spring. Due to this the pressure reducing valve opens until equilibrium state is reached again. This prevents to exceed the set outlet pressure. This means regardless a decreasing or increasing inlet pressure the outlet pressure stays at a constant level - the outlet pressure (working pressure) is not linked to the inlet pressure. The higher the pressure on the outlet side, the more the valve closes. The more the pressure on the outlet side decreases below the preset value the more the valve opens.
V78 V8 0 7 3 6 9 3 8 8 5. Valve body 0. Locknut. Upper valve body. Adjusting screw 3. Diaphragm. Hexagonal socket-head bolt. Piston. Cap 5. Compressor 5. Hexagonal socket-head bolt with nut and covering cup 6. Spring plate 6. Valve bottom with O-ring 9. Compression spring 7. Ring seal. Valve body. Adjusting screw. Upper valve body. Hexagonal socket-head bolt 3. Diaphragm 3. Washer. Piston. Cap 7. Pressure plate (top) 5. Hexagonal socket-head bolt 8. Pressure plate (bottom) 6. Valve bottom with O-ring 9. compression spring 8. O-Ring 0. Locknut 0 6 9 8 8 6 V8 < 0 5. Valve body. Adjusting screw. Upper valve body. Cap. Piston 5. Hexagonal socket-head bolt 6. Spring plate 6. Valve bottom with O-ring 9. compression spring 8. O-Ring 0. Locknut 0. Piston base P / T-Diagram P (bar) PP-H, PVDF 6 5 3 0 9 8 7 6 5 3 0 T ( F) -58-8 3 6 9 5 8 7 30 PVDF PP Types V8, V8, V78, V86, V86, V786, P0, V9, V95, V5, Z700, Z70, V85, V85 PVC-U -50-0 -30-0 -0 0 0 0 30 0 50 60 70 80 90 00 0 0 30 0 50 T ( C) PP PVDF 0 00 80 60 0 0 00 80 60 0 0 0 P (psi) P0630309 P: Permissible pressure in bar, psi / T: Temperature in C, F The pressure temperature diagram is based on a lifetime of 5 years and the medium water or similar media.
Type V78 Type V8 3
Type 8
Dimensions V78 d DN Zoll L L I H h D PVC-U cement PP/PVDF fusion PVDF-HP / PP buttfusion BCF / IR mm mm Inch mm mm mm mm mm mm 6 0 3/8" 3-0 38 8 83 0 5 /" 3 7 0 38 8 83 5 0 3/" 5 90 0 05 65 3 5 " 5 90 0 05 65 0 3 /" 6 6 8 95 65 50 0 /" 6 6 8 95 65 V8 d DN Zoll D h H L L L L PVC-U cement PVDF-HP / PP buttfusion BCF / IR PP/ PVDF PP/PVDF fusion PP/ PVDF mm mm Inch mm mm mm mm mm mm mm 6 0 3/8" 70 00 30 3-5 0 0 5 /" 70 00 30 3 50 5 0 5 0 3/" 00 3 80 7 90 85 80 3 5 " 00 3 80 7 90 85 80 0 3 /" 30 75 30 0 8 30 50 0 /" 30 75 30 0 5 30 63 50 " 50 0 85 60 80 50 75 65 /" 00 50 350 300 300-306 90 80 3" 50 305 5 360 360-370 0 00 " 300 35 95 0 0-30 5
V8 d DN Zoll D h H L L L L PVC-U cement PVDF-HP/PP buttfusion PP / PVDF PP / PVDF PP/ PVDF fusion BCF / IR mm mm Inch mm mm mm mm mm mm mm 6 0 3/8" 70 00 30 3-5 0 0 5 /" 70 00 30 3 50 5 0 5 0 3/" 00 3 80 7 90 85 80 3 5 " 00 3 80 7 90 85 80 0 3 /" 30 75 30 0 8 30 50 0 /" 30 75 30 0 5 30 Specifications Pressure ranges for all pressure regulating valves shall be the following: DN 0 50 from 0 up to max. 0 bar DN 65 80 from 0 up to max. 6 bar DN 00 from 0 up to max. bar Following types and sizes shall be available: compact Pressure Reducing Valve with an integrated manometer, sizes DN 0-00 mm (V8) compact Pressure Reducing Valve offering easy adjustment and real time visual control of the actual pressure reduction on the integrated manometer, sizes DN 0-0 mm (V8) compact Pressure Reducing Valve, offering an easy adjustment, excellent flow rate and very low hysteresis, sizes DN 0-0 mm (V78) Planning Fundamentals The following link will lead you to the Georg Fischer Planning Fundamentals. These detailed documents will support you by choosing the right valve for your application. http://www.gfps.com/content/gfps/com/en/support_and_services/planning_assistance/planning_fundamentals.html?lang=en 6