United Conveyor Corporation

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Vacuum-Pressure Transfer System

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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)

Wet-To-Dry Conversion Brochure

Fly Ash Brochure

Fly Ash Brochure A4

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.