Reverse Circulation piping installation query

[knapee]

Dear Sir

There is two canned pump which is operated in a slurry fluid. I doubt why there is a rule for this canned pump as following :
1. Do not connect the reverse circulation line to another pump's reverse circulation line. The reverse circulation line
of each pump must be piped separately to the vapor zone of the suction tank, even when the other pump is used as a stand by pump.
2. These two reverse circulation lines have to be connect to the vapor suction line cause the column can't be open a hole for a nozzle.
So these two reverse circulation line is proper to put in front of the check valve or after the check valve ?

Please give me any comment and I will very appreciated.
Thank you very much.

 

[BigInch]

It could be because of overheating concerns that they say the recirculation line must go back to the tank. The connection should probably be between the pump and the check valve. Not sure because it would be easier to see the configuration if you posted a diagram instead of the xls.

Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso

 

[Pumpsonly]

Please check your pump again. Canned motor pump with reverse circulation is not suitable for slurry fluid.
Canned motor pump with reverse circulation line is used for high vapour pressure ( volatile) liquid and is vertically mounted with the motor end at top. This is to prevent the hot liquid from going back to the pump suction after picking the heat from the motor.
The R/C line is connected at the top of the motor and should goes back to the vapour zone of the suction tank to prevent vapour lock in the line. This line also double up as a vent line for pump priming.

 

[knapee]

Dear Sir

Thank you for your reply. Base on API 685,
Canned motor pumps are one-piece,statically-sealled,
primarily volute-type, environmentally sensitive, and
other hard to handle fluid. But it didn't mentioned
that it can't handle slurry. Could you please
share your reference from?

Really appreciated your help, and thank you very much.

 

[Pumpsonly]

Standard configuration Canned motor pump use the pumped fluid to lubricate the bearings inside the motor.Therefore they need clean liquid.

For slurry application a different construction type is used.

http://www.teikokupump.de/English/Products/products.html

http://www.nikkiso.com/products/pump/canned/variation.html