For certain applications, UCC recommends a “combination” vacuum / pressure transfer system. These systems combine the simplicity and lower headroom requirements of a vacuum system under the hoppers with the high capacity and long distance conveying capability of a positive pressure system.
In a combination system, a short vacuum system conveys ash from the hoppers to a transfer bin. A longer pressure system conveys ash from the transfer bin to a remote storage bin for disposal.
Possible Combination NUVEYOR Vacuum System and NUVA FEEDER Pressure System:
NUVEYOR Vacuum System:
- Ability to stop and restart due to low ash-to-air ratios
- Low headroom requirements below the fly ash collection hoppers
- Capable of handling a wide range of ash types
- Full load/no load control allow system to achieve rated capacity more efficiently
- Wear sections follow each change in pipeline direction
- Low maintenance at precipitator and economizer areas
- Single pneumatic valve under each hopper
- Single air intake per row
- One I/O per hopper valve
- No plugging
- Proven temperature tolerant design for large particle economizer ash
Performance Specs:
| Max Distance: | 1,500 ft (4,500 m) |
| Maximum Capacity: | 80 TPH |
| Mass Ratio ash : air: | 5-22 |
| Air Velocity: | 3,000 – 5,200 ft/min (16-27 m/sec) |
| Maximum Conveyor Line Pressure: | 20 in Hg (530 mm Hg) |
| Maximum Prime Over Pressure: | 22 in Hg (560 mm Hg) |
NUVA FEEDER Dilute Phase Pressure System:
- Dilute to medium phase conveying
- Long distance conveying without the need for a transfer vessel
- Capable of high capacity conveying
- Control system keeps the conveying line filled for longer periods, resulting in high conveying efficiency and lower operating costs
- Low sensitivity to ash characteristics; capable of conveying larger and more dense particles
- Proven ability to handle economizer ash
- Ability to stop and restart system operation without plugging due to moderate ash-to-air ratios
- Full load control prevents line plugging
- The use of a bin vent filter reduces maintenance on silo roof
- Highly stable condition with no pressure surges
- Ideal for high altitude applications where vacuum systems are not effective
Performance Specs: | Max Distance: | 8,000 ft (2,400 m) |
| Maximum Capacity: | 175 TPH |
| Mass Ratio ash : air: | 5-22 |
| Air Velocity: | 2,400 – 4,800 ft/min (12-25 m/sec) |
| Maximum Conveyor Line Pressure: | 40 psi (275 kPa) |
| Maximum Prime Over Pressure: | 45 psi (300 kPa) |
Why would a vacuum/pressure transfer system be used over either a vacuum or pressure system?[+]
A vacuum/pressure transfer system would be recommended where there is a need for long conveying distance and high capacity is needed along with keeping headroom low.
Pipes and Fittings - Nuvaloy, Dur-rok, Ceramic, Expansion Joints, Connections
.jpg)
Gates/Valves – Fly Ash Diffusers, Fly Ash Intakes, Swing Disc, 40D, Butterfly, TERS, Hopper & Bin Isolation Gates, Sheardisk, Vent and pressurizing valves
Tanks/Vessels – Silo level probes, storage bins
Separating Equipment – Bags, Cages