Theory bites are a collection of basic hydraulic theory and will touch upon pump design and other areas of pump industry knowledge.
The allowable operating range, or AOR, is the portion of a pump curve determined by the pump manufacturer where the pump can be operated continuously without significantly affecting the performance or life of the pump.
The Allowable Operating Range is determined by the pump manufacturer through engineering analysis, testing, and experience. It is the range of operating conditions that the manufacturer considers to be acceptable. While a pump may be operated intermittently for short periods of time outside of the AOR, the large majority of operation should be maintained within the AOR.
The AOR, in contrast to the POR, is defined by the pump manufacturer and not by a standard specification such as the Hydraulic Institute or API610
Source: EKWESTREL CORP by Randal Ferman and Introduction to Centrifugal Pump Fundamentals.
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Thank you Maria for your enlightening series of Theory Bites. It is a wonderful idea and helps present facets of a broad subject in easily digestible bites.
A remark or two regarding pump Allowable Operating Range (AOR): Over the years I have seen more than a few pump installations. AOR is, perhaps, given the greatest attention during the plant engineering and equipment selection phases. After that, you have all the heavy realities of operating and maintaining the plant. And at that stage, equipment operation to keep the plant and process up and online is the priority. With that in mind, a pump will be called upon to operate wherever the needs of the plant demand that it operates. Reliability focused engineers battle to operate the equipment within design parameters and properly maintain them. But the exigencies of plant operation will always govern.