8 replies to this topic

[ankit.kala2007@gmail.com]

Hello everyone,

 

Please help me out in understanding whether we can have a permanent pump whose pressure can be adjusted (varied) so that i can dechoke my instrument tubings & small LPD's  which are susceptible to choking.

As the hand pump's we use to dechoke are based on back pressure of fouling(choking) inside the tubing and when a small path is made in between the choking the back pressure cannot be attained hence dechoking of line fully cannot be achieved.

 

1. If possible which type of pump should be preferred.

2. How can I come to know that the tubing is fully dechoked.

 

 

 

Regards

Ankit

 

 

 

 

[Art Montemayor]

Ankit:

 

Please educate me on your use of the term "dechoking".

The word choke means strangle (in other words, you are throttling flow).  The usual use of this term is in reference to sonic flow of gaseous or vapor flow.  Sonic flow of a compressible fluid is called "Choked Flow" (not chocked flow, as a lot of engineers call it in the internet).

 

I don't think you are saying that you have sonic flow inside your instrument tubing.  Could you clear up my conception of what you are describing?

[Aranga]

Hai Ankit,

 

   For instruments tubings case, we used to have minimal, continuous stream of nitrogen flow with a rota meter inside the HP and LP legs. So that it wont be pluggedup. You can use the same to build up pressure to purge it (eventhough if it is Plugged).

 

  For LPDs I have seen a mechanical device in Refineries, Outside it has a screw type handle. inside it has a flexible rod(metal wire like). So you have to disconnect the LPD downstream flange, then connect this device, screw the wire in,... Once the choke is removed, you can see Pressure in the gauge attached with it. This is the safe methode to remove wax like choke in process lines.

[ankit.kala2007@gmail.com]

Art Montemayor: Sir, choking means obstruction in tubings such as Vaccum Residue PT's and LT's. As some times due to process upset Vacuum residue may coke up in lines of instrument tubings. and restrict the flow resulting in wrong pressure and level readings...

Edited by ankit.kala2007@gmail.com, 17 March 2013 - 01:15 PM.

[ankit.kala2007@gmail.com]

Aranga: Sir the arrangement you are talking about is based on back pressure due to chocking. As a small passage is made through chocking there is not much back pressure. For that i want a permanent pump which can deliver pressure which can remove chocking as well as may not damage tubing or LPD's....

 

Also please tell can we have small pumps whose pressure can be varied,.....

Edited by ankit.kala2007@gmail.com, 17 March 2013 - 01:16 PM.

[Aranga]

"Also please tell can we have small pumps whose pressure can be varied,....."

 

 

Sorry Ankit,

 

I have no Idea regarding This...

 

 

 

[jr31]

Hello,

 

See attached literature which shows typical schemes which could be considered.

[ankit.kala2007@gmail.com]

jr31: cannot find the attachment...... pls attach again

[ankit.kala2007@gmail.com]

Can any one please help me to develop a scheme for a reciprocating pump with variable discharge pressure.......