General Pump Overhaul Specifications

[sandriver]

I have an assignment from the power plant manager to put together a general pump overhaul specification which will be used in conjuction with a generated PO to have the plant's spare pumps overhauled at the vendor's shop. I is planned to reference this overhaul specification as pumps are sent out for routine overhauls, as such I would like to look at various examples to formulate this specification. We have vertical mixed flow and horizontal centrifugal pumps of all types Any help would be highly appreciated. THANKS!!

 

[Zapster]

Have you asked your overhaul vendors if they have any overhaul specifications that you may review?

 

[Artisi]

I think my specification would read something along these lines;
"Please dismantle, inspect and report on all components together with suggestions for refurbishment / replacement to as new tolerances."

It should be your decision what to repair / replace / accept as servicable in conjunction with your own inspection of the dismantled unit, review of the report and discussion with the pump vendor, if it is not the vendor or an experienced repair shop it will be entirely your decision.

Remember, it's your pump, it's your money and you know that the application is and what your own company policies are regarding refurbishment and what is acceptable.

Naresuan University
Phitsanulok
Thailand

 

[JJPellin]

I prefer to see a specific set of specifications for the most common measurements. This provides a nice guideline so that any repair can be done with good quality without having to have an engineer review each measurement to determine whether it is acceptable or not. The value of this approach depends on the number of pumps and the number of repairs that you do. It also depends on the quality of the outside repair shops that you send pumps too. Any shops that I deal with have their own set of repair specifications, but I send them my specifications and require that they notify me if any measurements are outside of my numbers. I have pasted in a part of our specification summary sheet. I am not sure if it will come out in a readable condition. All of the units are in inches and this is intended for single-stage,overhung, API centrifual pumps 300 horsepower and smaller.

Item Specification Renew/Correct

Coupling Hub to Shaft
up to 2" Shaft 0.000" to 0.0005" T >0.0015" L
>2" and Larger Shaft 0.000" to 0.0010" T >0.002" L

Impeller to Shaft (Overhung) 0.001" to 0.002" L >0.003" L
Center Hung Pumps - Refer to OEM Manual or Seek Engineering Support

Bearing to Housing ISO H6 >Table +0.0005", <Table
Bearing to Shaft ISO k5 <Table -0.0005", >Table

Wear Rings
Clearance As per Table As per Table
Fit (Maximum 0.004" T) 0.0005" / inch dia T 0.0005" / inch dia T
Out of Round --- >0.005"

 

[stanier]

Make sure you specify that the motor's insulation be tested. Impedance between the phases should be within 1%. Do a thermal image test to see if there are any hot spots in the insulation. Check that starting current matches the manufacturers specification.

Geoffrey D Stone FIMechE C.Eng;FIEust CP Eng

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