VF, VFT, and VFH butterfly valves are designed for regulation and control of gas flow and air flow in combustion processes. Valves can be operated manually using a lever (to setup the high-fire rate of the burner) or automatically using a servomotor (modulating or staged control) or a solenoid actuator (two-stage control).
Feature
- Valves are made of aluminum (VF/VFT types) or cast-iron (VFH type), with wide range of threaded connections and for installation between EN 1092 flanges.
- Possibility to have one-size or two-size reductions of the nominal diameter for VF/VFT types.
- Suitable for use with air and non-aggressive gases according to EN 437 (VF/VFT types); heated air and flue gas (VFH type).
- Low leakage when valve is in closed position (VFH type provided with butterfly disc stop).
- The VFH type is provided with a double-eccentricity disc and a spring to reduce the backlash. This results in a high precision adjustment and avoids valve floating.
- Operated by manual lever, servomotor or by solenoid actuator.
- All components are designed to withstand any mechanical, chemical, thermal condition occurring during typical service. Effective impregnation and surface treatments have been used to improve mechanical sturdiness, sealing, and resistance to corrosion of the components.
Specification
| VF, VFT | VFH | |
|---|---|---|
| Connections | Threaded from Rp3/4 to Rp2 according to ISO 7-1 From DN40 up to DN150 for fitting between two flanges according to EN 1092 PN16 | From DN40 up to DN200 for fitting between two flanges according to EN 1092 PN16 |
| Rotation angle | 0 / 90° adjustable | 0 / 90° adjustable |
| Ambient temperature | -15°C ... +60°C | -15°C ... +60°C |
| Media type | Air and non-aggressive gases according EN 437 | Heated air and flue gas |
| Max. media temperature | +60°C +200°C for use with air only (special version on request) | +250°C +450°C with dissipators (optional kit) |
| Max. Operating pressure | 500 mbar (50 kPa) | 150 mbar (15 kPa) |
| Max. Pressure loss @Vmax | 150 mbar (15 kPa) | 45 mbar (4,5 kPa) |
| Flow rate | See Datasheet | See Datasheet |
| Materials in contact with fluid | Aluminium alloy Copper alloy Stainless steel Nitrile rubber (NBR) Fluoro elastomer (FPM) Polytetrafluoroethylene (PTFE) | Cast iron Stainless steel Polytetrafluoroethylene (PTFE) |
| Driving systems and actuators | - square shaft 8 - round shaft Ø10 - manual lever - solenoid SR/SL/ST - servomotor MZ - servomotor MZ with lever | - manual lever - solenoid SR/SL/ST - servomotor MZ |