4 replies to this topic

[Pingue2008]

Dear all,

 

This question might seem trivial for some, but for me it is a bit troublesome. My understanding is that a vacuum producing equipment is needed when the vessel on which it is subjected needs to operate below atmospheric pressure. if my understanding is correct, then, how does one establish that a vessel need to operate under vacuum (under atmospheric pressure). I have been studying the workbook that Mr. Art Montemayor posted (producing and maintaining vacuum) and it is incredible. I have been told that such and such vessel should have a vacuum producing equipment on them, Now I want to be able to establish that on my own. please kindly advise your point of view.

 

Thank you,

Edited by Pingue2008, 11 July 2013 - 07:20 AM.

[Mabhiza]

Pingue2008

 

I think what you should understand is that vacuum is sub atmospheric pressure. This means that you have a negative or sucking pressure. 

A typical example of  vacuum creation is when someone is drinking a cool drink using a straw. When you draw the contents of a can, you actually creating vacuum and the liquid inside the can will flow against gravity and come to your mouth.

 

Vacuum is created either by a vacuum pump or a thermo compressor (Steam jet ejector) but not limited.

 

Certain factors in your design determine whether to use vacuum or not. you don't decide overnight to use vacuum. I once worked for an oil refinery and we use both vacuum pump and the thermo compressor to create vacuum. The reason was that we wanted to remove all the vapours in the system and to prevent our oil from burning because the temperatures we used where quite high.

 

I hope this helps.

 

Rds

 

Mabhiza

[Pingue2008]

Mabhiza, on 11 Jul 2013 - 09:01 AM, said:

Pingue2008

 

I think what you should understand is that vacuum is sub atmospheric pressure. This means that you have a negative or sucking pressure. 

A typical example of  vacuum creation is when someone is drinking a cool drink using a straw. When you draw the contents of a can, you actually creating vacuum and the liquid inside the can will flow against gravity and come to your mouth.

 

Vacuum is created either by a vacuum pump or a thermo compressor (Steam jet ejector) but not limited.

 

Certain factors in your design determine whether to use vacuum or not. you don't decide overnight to use vacuum. I once worked for an oil refinery and we use both vacuum pump and the thermo compressor to create vacuum. The reason was that we wanted to remove all the vapours in the system and to prevent our oil from burning because the temperatures we used where quite high.

 

I hope this helps.

 

Rds

 

Mabhiza

Mabhiza,

Thank you for your comments. Could you please identify those factors that dictate the use of vacuum in design?

[Mabhiza]

Pingue 2008

 

You  use vacuum if there is vapour that you want to take out in your system. For example, in evaporators it's where you would normally use vacuum because you want to suck out the vapours.

Or you can use vacuum if your process requires large amounts of energy to heat it up, remember for the relationship between Pressure and temperature.

 

So basically, the vacuum is mostly used to pump vapours.

 

Hope this help

 

Kind Rgds

 

Mabhiza

[Pingue2008]

Mabhiza,

 

Thank you.