The very critical detail of conveying distance is required before a start can be made here. Number of bends is also required and some idea of the approximate value of vacuum available at the plant location. Then the source of the ash is required, whether from electrostatic precipitator or economiser hoppers. ■

Dear Sir,

In my opinion a Vacuum system is not suitable for fly-ash pneumatic conveying. I can recommend you the system based on a "Flow Feeder" to convey fly-ash. The system has been developed by our company and it is based on positive air pressure. To make a basic calculation I need additional data about your system, like the pipeline description (distance, transport height, number of knees and their angle, material bulk density etc.). If you interest in our conveying system I will send you the pneumatic conveying questionary and some leaflets by E-mail.

With best regards

Petr Rayman

Technical Director

RAYMAN Ltd. Kladno

Czech Republic

E-mail: petr.rayman@rayman.cz ■

In addition to the information provided by the other members, you also need to be aware that vacuum systems are often limited by the amount of actual vacuum available.

If your conveying distance is large, you may want to consider a combination system where the collection from a bag house or ESP is done economically by a vacuum system and then a pressure transport system transfers the material longer distances to a storage silo.

Regards ■

Invincible is now part of Gardner Denver and has combined with Lamson and Hoffman. Please forward your question to Charles Howden (Charles.Howden@gardnerdenver.com) at Gardner Denver United Kingdom and he will connect you with an engineer covering Bangladesh. ■

Dear Mr Fahim

For a system calculation, it is necessary to know the system layout.

If you can provide the following information, I can make a preliminary system design and –calculation.

product : (fly-ash) , particle density , bulk density , particle size ditribution.

Pipe line : (A full description of the various pipesections with their length and angles)

or

horizontal length , vertical length , number of bends

pick-up of fly-ash : suction nozzle , from a fluidized hopper or –floor , from a feeder

separation of fly-ash : in a filter receiver vessel , rotary lock

Any additional information that you feel useful.

After the first calculations, the design can be improved

Awaiting your reaction ■

G'Day Fahim,

Vacuum conveying of flyash which is an abrasive material over long distances requires quite a bit of vacuum which standard roots blowers are not able to provide. These machines typically work upto 15" Hg.

However on systems such as this we use a specially designed high vacuum roots blower which is cappable of upto 28" Hg without any requirement of cooling fluid or water thereby making it ideal for such applications.

We can propose a pneumatic vacuum conveying system for you based on this set-up.

However we would require additional information such as:

* total conveying distance

* no of bends

Also is the fly ash at ambient or elevated temperature.

Please reply to the following e-mail address and we will get back to you at the earliest

harish@nucon.com.sg

Regards

Harish ■

Terence

Teus is one of the most knowledgable individuals today with respect to the pneumatic unoading of maritime vessels.

His conveying system designs and suggestions from a technical perspective must be incorporated into a complete system design considering all of the other parameters regarding the unloading, storage and reclamation of the product.

I have worked with Teus in the past and if you are in need of services to incorporate Teus's technical recommendations into a complete engineered system, our firm is willing to discuss this with you.

All the Best ■