API 686 requirements for pump shim
API 686 requirements for pump shim
(OP)
Dear All,
Is it acceptable the pump to be shimmed during alignment? The situation is that during our final alignment, we have noticed that the motor needs to be lower more, to have the alignment tolerance. However, the motor has no shim already and that we need to shim the pump in order to have minimum 3 mm at the motor as per api 686? hoping for your field experiences.,...
Is it acceptable the pump to be shimmed during alignment? The situation is that during our final alignment, we have noticed that the motor needs to be lower more, to have the alignment tolerance. However, the motor has no shim already and that we need to shim the pump in order to have minimum 3 mm at the motor as per api 686? hoping for your field experiences.,...





RE: API 686 requirements for pump shim
If, on the other hand, the motor truly has no shim at all, then you have a couple of choices. You can shim to raise the pump as you suggest, or you can machine down the motor base to allow for shims to be added. Obviously, it is much more expensive and time consuming to field machine the motor base. We had to make this same decision today on a pump. We decided to add shims under the pump. This is not the ideal solution, but it can be acceptable under some circumstances. In our case, the motor and pump were quite small and we had a time constraint that needed to be met. We decided that the addition of a single, ground spacer plate under the pump feet was the best option.
Johnny Pellin
RE: API 686 requirements for pump shim
Thanks for sharing your field experience. Our current situation is that i am on a client side for an ethylene cracker plant construction. However during the alignment of these overhung pumps, our contractor noticed that it cannot meet the API 686 requirement of providing the motor feet with a 3 mm shims and some installation even have 0 shims after the final alignment. What is a better solution to have a reliable pump/motor installation? To shim the pump or and in-place machining of the motor mounting pad. We are dealing with this problem about more than 50 pump/motor units...thanks...
RE: API 686 requirements for pump shim
I work in a maintenance organization and tend to default to thinking in terms of maintenance repairs of existing equipment. For a new construction, the vendor or contractor should meet the requirements of the contract including the technical specifications and standards for the machinery.
Johnny Pellin
RE: API 686 requirements for pump shim
requirement was not met in the first place.
If you can achieve the final alignment at site with less than 3 mm or 0 shim under motor foot, that will be acceptable. You don't need to put 3 mm shim at the pump and motor just to meet the 3 mm shim under motor footing.
Have you consider any hot alignment requirement?
RE: API 686 requirements for pump shim
Could you please comment on the paragraph below?
Shimming of pump is not acceptable.
Paragraph 6.3.4 of API 610 states that “Shims shall not be used under the pump. All pads for drive train components shall be machined to allow for the installation of shims at least 3 mm thick under each component.” (See attached file)
thanks,
RE: API 686 requirements for pump shim
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.)
RE: API 686 requirements for pump shim
To start with, look at a complete pump package and try to figure out the procedures in installation, piping and final alignment of the drive train.Then you will understand the reasons behind the statement.
RE: API 686 requirements for pump shim
RE: API 686 requirements for pump shim
The motor will only have the flexible power cable connected to it.Very often you will find the pump foot is doweled onto the baseplate support.
RE: API 686 requirements for pump shim
If we will put shims to the pump,
1. API 610 will be violated "shims is not acceptable at the pump".
2. As the pump/motor assembly including the skid/baseplate is under vendor warranty, it is still their responsibility to comply on the contract requirements (API 610 requirements).
3. High reliability installation providing that the motor has the only one that have shims which will provide more maintenance flexibility.
RE: API 686 requirements for pump shim
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.)
RE: API 686 requirements for pump shim
Yes this is provided / given to the vendor though it was not on spec but it was not given on their exception and deviation during the technical clarification meetings. Then it is their full responsibility to comply on the API610 standard...
RE: API 686 requirements for pump shim
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.)
RE: API 686 requirements for pump shim
RE: API 686 requirements for pump shim
During Pump to motor alignment, we achieved the alignment with just 0.5 mm shims under motor base but Client inspector insist to provide minimum 3 mm shims as per API-686 and Project specs requirement.
Can you advise me the reason behind minimum 3 mm shimming is must even if we achieved the alignment with 0.5 mm ?
RE: API 686 requirements for pump shim
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.)
RE: API 686 requirements for pump shim
Thanks for the information for the posting new question.
Your response for my same post in new thread will be highly appreciated and helpful to me.