4 replies to this topic

[a1986]

Dear Sirs,

 

i have received a process data sheet for a canned motor pump.. 

 

in this document should i find the indication of containment/control system and the indication of cooling system for bearings??

 

i think yes, but i'm very doubtful...

 

thanks

[ankur2061]

a1986,

 

The datasheet for your Canned Motor Pump (CMP) could preferably be in line with the datasheet template provided in API STD 685: "Sealless Centrifugal Pumps for Petroleum, Heavy Duty Chemical, and Gas Industry Services". This datasheet is titled as "Sealless Centrifugal Datasheet" and covers sections for both "Mag-Drive" and "Canned Motor" type sealless pumps.

 

Some idea about the information that needs to be furnished for a CMP can be looked up at the following link:

 

http://nrb.etenders....000DAE02801.pdf

 

Hope this helps.

 

Regards,

Ankur

[Atttyub194]

Dear a1986

 

Good day !

 

Your intent is not clear .However, following may be noted  based on what I have understood

1. Reference is made to API 685 para 6.10.9, which states " Lubrication/cooling of the bearings shall be by the pumped liquid or by a clean liquid from an external source. The use of an external system requires purchaser’s approval (see Appendix D).

In view of above you will not find " cooling water " for bearing cooling unless specified by the purchaser

 

As per referred standard,  pumpage from the pump casing enters the recirculation circuit to provide cooling and lubrication to the product
lubricated bearings and cooling to the primary containment shell. Heat is added to the pumpage as it  passes through the recirculation circuit. If sufficient pressure is not provided in the circuit, flashing of the pumpage will occur, and bearing failure could result. Flashing at the containment shell could result in excessive temperature rise of the shell and subsequent cavitation or vapor lock in the recirculation circuit. To avoid these occurrences, the pressure temperature profile for the proposed pump unit is to be analyzed by the manufacturer for the rated conditions and pumpage to assure that an adequate pressure margin

 

The confinement of the pumped liquid within a secondary pressure casing in the event of failure of the primary containment shell or stator liner is  some times required.

 

However, as per standard, The purchaser have to specify which of the following control/containment options the pump shall have:

1. Secondary control design (3.65). " The minimization of release of pumped liquid in the event of failure of the containment shell or stator liner is required or not".
2. Secondary control with leakage monitoring device(s) , (Secondary control system 3.66). " The combination of  devices (including a secondary pressure casing) that, in the event of leakage from the containment shell or stator liner, minimizes and safely directs the release of pumped liquid. It includes provision(s) to indicate a failure of the containment shell or liner is required or not"
3. Secondary containment design (3.63). " The confinement of the pumped liquid within a secondary pressure casing in the event of failure of the primary containment shell or stator liner is required or not "
4. Secondary containment with leakage monitoring device(s)  (Secondary containment system 3.64). "A combination
   of devices that, in the event of leakage from the primary containment shell or stator liner, confines the pumped liquid within a secondary pressure casing that includes provisions to indicate a failure of the primary containment shell or stator liner. is required or not"

 Additionally, as per 6.8.2 The secondary control system shall have a stand-by life of at least 25,000 hours in a pump operating mode

 

Reference is made to 9.1.2.2 , " To minimize leakage around the external shaft in the event of a primary containment failure, the secondary

control system shall include a replaceable, non-sparking restriction device. Lip seals are not acceptable. "

 

You will find all the above information to be filled in API-685 data sheet . Please do ask your engineering team to provide data sheet filled on API-685 format. Probably, then your all queries will be resolved

 

API-685 data sheet clearly specifies what should be filled by manufacturer and what should be specified by the purchaser. The ambiguity only arises when we try to develop our own formats for pump specifications

 

Hope I have given the appropriate clarification. If some thing is missing please do attach the data sheet so that I  can review and give you some comments as per my knowledge and experience

 

Best regards and God Bless You

 

Ahmed Attyub

[prengr]

Dear a1986,

 

In my opionion, the indication of containment/control system and the indication of cooling system for bearings should be shown on data sheet case by case.

If your pumping fluid may make some mechanical problem, you should indicate pumping fluid property and characteristic(e.g solid concentration and hardness etc) to be correct the containment/control system design by the pump manufacturer. Actually, because there are many canned pump manufacturers and there are many different containment/control system, the correct impormation from purchaser is important.

And cooling system for bearings for canned pump is usually considered by pumping liquid recirculation. In case that the temperature of pumping liquid temperature is too high, the pump manufacturer needs external cooling by cooling medium(water, chilled water etc). For this case, your data sheet shall show the information of cooling medium. For your reference, in my case, if the fluid temperature is over 120~130 degC, the manufacturer requested external cooling system.

 

If you visit the canned pump manufacturer's web site, you can find valuable information.

(Main canned pump manufacturer - Hermetic, Teikoku, Nikkiso etc)

 

Thanks.

[a1986]

Dear Sirs

 

i would like to thank you, for your willingness.

i was looking for a confirmation, since i had read API 685. unfortunately has created a strange situation about data sheet, and i think that when i will engineerized a process data sheet, i had to ask to purchaser about these info's.

 

i think these infos are necessary on a proper data sheet for canned motor pump.

 

thank