Shims under baseplate for lube oil centrifugal pump

[svkd]

Guys,

For new installation we faced issue The contractor has put shim under pump base plate so Is it acceptable to use shims under base plate. I have checked in API 610 & 686 but no information available whether shims under base plate is allowed OR not.
Guys , If please share if know any standard says about this and also I don't mind any opinions also.

 

[jayrod12]

How was the baseplate designed? if it was designed to span between shims, or levelling nuts, then I would say it should be ok.

If it was designed for uniform bearing, then it would not be ok and they would need to be grouted into place.

 

[LittleInch]

There are many options available in API 610 which determine whether a base plate is designed to sit on concrete or some other supports.

E.g. 7.3.8

7.3.18 requires bolt leveling screws which are no different to shims

Normally you level with shims located at the anchor bolts, bolt down, then grout under the baseplate structural members with non shrink grout

Find out what the design of the pump / base plate is then you've got your answer.

Your attachments don't open. you can't just paste into the post unfortunately.....

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Also: If you get a response it's polite to respond to it.

 

[Tmoose]

I'd be looking carefully at the pump manufacturer's installation instructions too.

 

[svkd]

Guys , see attachment ,the drawing showing shim location at base plate.

 

[LittleInch]

Looks a bit odd as it seems there are longitudinal supports along the edge of the skid supplying a constant support along the base plate edge.

However if the base plate has been designed to allow it then it's OK. (7.3.13 of API 610)

you need to see what the pump data sheets says and what the vendor installation instructions say for that particular pump.

e.g. 7.3.3 states "If driver and pump size permit, baseplates shall have standardized dimensions as given in Annex D and shall be designed for grouting."

Have they used standard baseplates?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[svkd]

They have put shims under base plate for shaft alignment of pump & motor , earlier they put these shims under pump but when we intervene they removed the shims from pump and installed them under base plate.

vendor has mentioned nothing about leveling the base plate with shims.
I don't know whether it is standard baseplate OR How I canm check whether it is standard OR Non standard baseplate?

 

[LittleInch]

svkd,

What you just stated makes no sense I'm afraid.

If the shims are for alignment of motor and pump, both of which are bolted to the baseplate, then you adjust the motor or pump by means of shims to change the relative orientation of each. Why did you tell them to remove them??

If they've put it under the whole base plate, then this will not affect the alignment of pump and motor unless they've managed to flex the baseplate because you've stopped them doing something which is perfectly normal and acceptable.

You need to TALK to the vendor to understand what is and is not acceptable for his baseplate, but I would suggest base don the info available that you remove the shims under the baseplate, let it sit fully supported on what appear to be beams under each side and then allow the contractor to align the pump and motor by adjusting the relative position of each of them using shims under the bolt hole location of each. Just be careful if you have a cast iron pump body that the shims are both sides of the bolt hole otherwise you risk cracking the pump casing due to excessive bending force ( been there - done that).

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[svkd]

LittleInch,

They have put 15mm shim under pump feet for alignment.Is shim stack of 15mm(total no of shims 8) is acceptable under pump feet? As per my exp and engg standards it should not be more than 5 no. of shims and shim stack should not be more than 12mm.That why I told them to remove these shims and when I went there the next day they removed the shims from pump feet and put them under base plate.

 

[LittleInch]

15mm is fairly steep alright, but it still doesn't make clear how that works. Shims under the pump affects the alignment between pump and motor. Shims under the baseplate affects entire unit.

I think you need to find out what they're doing and call the pump vendor to get his view. Not sure if api limits max shim height, but vendor instructions normally limit it.

Is the contractor experienced in pump installation? Might be better to pay the money now and get the vendor to send out an installation technician.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Ron]

Improper bearing will cause vibration to not be uniformly transmitted to the base, thus likely reducing the life of the pump or its bearings. Shims are also likely to vibrate out and cause the problem to worsen.

 

[LittleInch]

See API 610 - 7.3.6, limits max no of shims to 5 and 13mm thick.

It does seem to allow solid blocks up to 5mm thick to be used in addition to shims, where there is a need for this.

Something still doesn't sound right on this pump though

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[svkd]

LittleInch,

Any standard you know ,which says not to shim the base plate of this kind?

 

[LittleInch]

svkd,

I don't know what type of baseplate it is.

To repeat myself - most baseplates will be designed to be adjusted to make sure the baseplate fits onto its foundations / supports without becoming stressed and distorted. Most baseplates are then grouted under the baseplate supports to provide continuous support.

Some baseplates are designed to be e.g. mounted on structural members or feet.

You need to really be talking to the pump vendor I think.

A picture would help...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[maxdistortion]

It seems to me that they shimmed to get level but as LittleInch mentioned, it does not quite sound right that they got the same result from shimming a corner of the base to shimming the motor feet. At 15mm I'm sure they didn't need a machinist level to tell them that. My concern would be that the base of the pump will have air gap and it will vibrate excessively.

If this were my problem, I would look at the following:

- Who set and grouted the base, and check survey records for it.
- Does the pump base and pedestals meet tolerance? the base may be warped or pedestals nor properly machined
- Is it an API or an ANSI pump? your tolerances higher in ANSI and those pumps tend to be more forgiving.
- Who will be paying for the fix? it is obvious that there is a problem here. If the client is paying for it, they may want to save costs and try to live with a compromise. If the contractor is at fault because they set and grouted the base off level, then you should push to have them provide you with a solution that does not involve 1/2" shim packs. If the pump base or pedestals are out of tolerance, warped, then the vendor should include this fix into their warranty, or fix the base for you.

It would be helpful to know pedestal to pedestal level readings, soft foot and coupling alignment reading.

And is the other pump experiencing problems? There are so many possible problems and solutions here, and they really depend on circumstance and pump measurements. Its impossible to make assumptions that will work for you, except that what the contractor gave you is hokey. They might not know what they are doing.

BTW lube oil pipe and pumps tend to give us the most grief.