Pump Suction and Discharge Nozzle (Leveling) 1

[Tilas]

Hi,

I am currently installing my API 610 pumps as a pre requisite for grouting . I had the motor removed and have the motor mounting pedestals leveled to at least 0.25mm/m (API 686 requirement).I have leveled the pump mounting pedestal also within the same tolerance (without removing the pump as there is still spare there to do the level readings). I have done this by adjusting the vertical leveling screws which is available near anchor bolt places on the pump.

My question would be , do I still need to level the pump suction and discharge nozzle even though I have already leveled both pump and motor pedestal? I have searched API 686 but there is no clause there to the leveling on the pump nozzles.

Pump Date :
End/Top OH2 Pump
Suction Nozzle : 3"RF 300 lbs
Discharge Nozzle : 2" RF 300 lbs

Thanks,
Tilas

 

[JJPellin]

No. Leveling the pump flanges would require shimming between the pump and the base, which is not desirable. If the pump and base are well made, the flanges will be close to level with the pedestals level.

Johnny Pellin

 

[Tilas]

Hi JJPellin,

Thanks for your response.

But what if the I can make the motor/pump pedestals within API 686 acceptable limits like within 0.25 mm/m (API 686) , but the pump flange the best that I can get is like 0.40mm/m. In this case I cannot do anything on the pump flange level as you have pointed out that shimming in the pump side is not a desirable.

I understand that as long as I have my piping flange properly aligned/parallel with the pump nozzle and the gap is within acceptable limits of API 686 then the 0.40mm/m level of the pump flange would not matter much. Of course we would also monitor the movement of the shaft while torqueing the pump flanges to see that the movement does not go beyond 0.05mm after both suction and discharge nozzles has been torqued to 100%. Besides , API 686 does not mention anywhere that I need to level my pump flanges, it only mentions pump/motor pedestal leveling.

I hope I'm doing it correctly. Let me have your thoughts.

Thanks,
Tilas

 

[Artisi]

To solve your problem, mount the pump onto to baseplate and then install the baseplate/ pump paying attention to correct positioning of the pump flanges- shim the underside of the baseplate for flange positioning.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Tilas]

Thanks Artisi,

That will solve my flange level problem. But it will give me off reading's on my motor/pump pedestals level.

So flange level is more important than the pedestal/baseplate leveling?

My baseplate could be twisted or something that's why I can both to be within level limits.

Thanks,
Tilas

 

[Artisi]

I know nothing about API standard but would think the pump / motor alignment is more important and would over rule any standard of baseplate mounting (outside of good engineering practice)

Is the pump baseplate a separate component to the motor baseplate?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Tilas]

Hi Artisi,

The pump and motor is in one common baseplate , within the baseplate they sit on two separate pedestals - one for the pump and one for the motor (machined mounting surface welded to the baseplates).

Yes , either way we are going to align the pump properly before and after grouting.

Thanks,
Tilas

 

[Artisi]

OK, I would mount the pump and motor onto the baseplate, pump bolted into position, motor temporarily held down-- position the flanges vertical / horizontal etc by shims / packers/levelling screws ensuring the baseplate isn't twisted / bowed or hogged etc. Fix the baseplate into position and fully grout it, once grouting is cured you can then align the motor to the pump and recheck everything.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Tilas]

Hi Artisi,

Thanks for your response. I'll consider doing that.

Thanks again.
Tilas

 

[JJPellin]

For API pumps, I would still recommend that you level the base plate in order to have level mounting surfaces for both the pump and motor. I would level the pedestals and let the flanges will be where they are. I would not level based on the flanges. You can deal with the piping alignment and pipe strain later. Once that base is grouted down to the foundation, it more difficult to do anything about it later.

Johnny Pellin

 

[chicopee]

Wouldn't a flex connection solve the problem?

 

[Tilas]

Thanks JJPellin,

For 2 of my pumps, I have no other choice but to do as you said because I already have grouted it. But I made sure that the mounting pedestals were leveled to at least 0.25 mm/m for those. As you said, pipe strains I will take care with the allowable parallelism, flange gap and controlled torqueing on the pump flanges of course with respect to monitoring the shaft movement while torqueing.

For the rest of the pumps not yet grouted, I would ask the owner which among the 2 method do they wish me to do and then take it from there.

Thank you all for your valuable inputs.

 

[JJPellin]

That specification for flange parallelism seems too strict. We don't even measure that anymore. Pipe-fitters fabricated that pipe using using a steel tape with a scale in 1/16 inch increments and you are expected to verify the flange gap using a feeler gauge in 0.001 inch increments. If the pump is an API design on a well designed base with well designed piping, it is not necessary to be so picky.

Johnny Pellin