Laval Nozzel VS Control valve for air flow control

Posted in: , on 28. Feb. 2006 - 08:00

For Dense phase conveying air control part,

Some company supply laval nozzel some use only control valve.

What is the difference in between?

I guess laval nozzel is better.

it controls flow with a lower and constant pressure drop, which control valve can not do, isn't it?

Thank you all

Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]

Gas Supply Systems For Dense Phase Conveying

Posted on 28. Feb. 2006 - 06:28

There are many types of gas supply systems for dense phase pneumatic conveying. These typically include:

Single Laval Nozzle

Single Laval Nozzle with an upsteam pressure regulator

Multiple Laval Nozzles

Multiple Laval Nozzles with a common or individual pressure regulators

A single flow control valve without pressure control

A single flow control valve with pressure control

Flow control valves with automatic leakage has compensation and pressure control.

All of the above with or without a bypass line for dilute phase conveying to purge the conveying line.

Selection of a gas supply system depends upon the design requirements of the dense phase conveying system. However, a basic requirement is maintain operation of the conveying system in the stable regime.

You may contact me if you need any assistance on your application.

Regards,

Amrit Agarwal

Consulting Engineer

Pneumatic Conveying Consulting

Emailolypcc@aol.com

Ph and Fax: 304 346 5125

Re: Gas Supply Systems For Dense Phase Conveying

Posted on 2. Mar. 2006 - 07:11

Among all your listed systems I think the most important point is to control and stablize the air flow. The difference is cost only.

Control valve can control flow but meantime it ifluences system pressure drop. So the control result may be not satisfied.

Is there any literature commenting on those different systems?

mmmmmmmmmmmmmmmmmmmany thaaaaaaaaaaaaaaaaaanks

Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]

Gas Supply Systems For Dense Phase Conveying

Posted on 2. Mar. 2006 - 04:19

Dear Shenjie,

I have not seen any publication that describes all of these options. To fill this gap I am planning to write an article on this subject.

Selection naturally depends upon the application, and also on costs. For example, conveying only one product at a fixed rate and over a constant distance is a lot simpler than conveying a variety of products at different conveying rates and also over different destinations. I fully agree that stability of the conveying system is a prime consideration for the gas supply selection.

Regards,

Amrit Agarwal

Consulting Engineer

Pneumatic Conveying Consulting

Email: polypcc@aol.com

Ph and Fax: 304 346 5125

Re: Laval Nozzel Vs Control Valve For Air Flow Control

Posted on 3. Mar. 2006 - 07:44

Dear Amrit,

Waiting for your article. Show some diagram in it to distinguish those systems.

Thanks

Shenjie Tel:+86(0)20 83553890,83550361 Fax: +86(0)20 83542314 [email]sj@chinabulk.com[/email] [url=http://www.chinabulk.com]Sino-Auto Technology[/url]

Re: Laval Nozzel Vs Control Valve For Air Flow Control

Posted on 8. Oct. 2006 - 07:04

For better controlling flow, main pressure regulator, pilot regulator and laval nozzle are used.

As we know, when pressure in conveying system is changed, the leakage will also be changed, thus we need to adjust gas flow to keep constant conveying. How to accomplish this? By pilot regulator and main pressure regulator, the inlet pressure of laval nozzle can be adjusted, then the gas flow through laval nozzle is adjustable, the key point here is to select sensitivity factor of pilot regulator.