Centrifugal Pump Assembly and Performance Parameters

From the Engineering ToolBox:

• ANSI/API 610-1995 - Centrifugal Pumps for General Refinery Service - Covers the minimum requirements for centrifugal pumps, including pumps running in reverse as hydraulic power recovery turbines, for use in petroleum, heavy duty chemicals, and gas industry services. The pump types covered by this standard can be broadly classified as overhung, between bearings, and vertically suspended.
• DIN EN ISO 5199 - Technical specifications for centrifugal pumps
• ASME B73.1-2001 - Specification for Horizontal End Suction Centrifugal Pumps for Chemical Process - This standard covers centrifugal pumps of horizontal, end suction single stage, centerline discharge design. This Standard includes dimensional interchangeability requirements and certain design features to facilitate installation and maintenance. It is the intent of this Standard that pumps of the same standard dimension designation from all sources of supply shall be interchangeable with respect to mounting dimensions, size and location of suction and discharge nozzles, input shafts, baseplates, and foundation bolt holes
• ASME B73.2-2003 - Specifications for Vertical In-Line Centrifugal Pumps for Chemical Process
• BS 5257:1975 - Specification for horizontal end-suction centrifugal pumps (16 bar) - Principal dimensions and nominal duty point. Dimensions for seal cavities and base plate installations.

You are asking which points to be ensured (or checked) to make nice pump in performance during assembly. Am I right?

Answer will be different based on who you are. Are you a member of pump company or are you an inspector?

One shall remember that pump's best performance is already fixed and determined when you finally decide to which model of pump to buy (or to assembly). This means that you shall do any and every effort to make the predicted performance manifested.

1. You a good engineer in pump company.

You to check the wear rings gap (or any clearance such as impeller backside and casing cover...) which will occur internal recirculation.

To reduce the bearing loss, check whether bearing is properly positioned and well tightened. Do not forget to give the good lubrication oil during performance test

To reduce mechanical seal loss, there is nothing much you can do. No leakage is just fine.

2. You are an Inspector.

I do not believe that inspector is able to freely acess any place, any pump in some specific pump factory unless contractually required. They can be invited just before performance test. Once the predicted performace is achieved within the tolerances, there is no more point to be checked. So, You may not have much of points to discuss with.

When the predicted performace curve is not achieved, then check the pump based on my answer para.1.

The specs quoted by lynlinch are all valid, but are specifically for the specification of new pumps. You can glean some very valuable information from the API610 on wear ring clearances and these are important to reduce internal recirculation and hence maintain performance. (as mentioned by poster 2). Balance grades of various components are also given.

API682 on shaft sealing will give you some good information on allowable shaft run-outs and seal chamber squareness etc. Bearing catalogues will give you all you need to know about bearing fits to shaft and bearing housing. Coupling fits etc can be gleaned from good engineering practice in books such as machinery's handbook.

Do not neglect simple things like pump body and impeller roughness, this can have a surprisingly large effect on efficiency.

And last but not least - follow the OEM's maintenance manual.

to get best out of ur pump u have to check the clearance between wear plate and impeller's back side & (2) clearance between impeller and wear ring in casing.

any minor change in them will reduce ur pump efficiency by 20-50%