So there will be different BEPs for different impeller/casing configurations?
Also, in regards to 1gibson's statement:
"Here is how this works: start with fluid conditions (including one design point, one head one flow), select pump, review the preliminary curve, buy pump, test pump with water, factor water test data to actual fluid conditions and see if it is within testing tolerances, ship pump, install pump."
When you say: "test pumpt with water" why would you retest the pump? Hasn't the manufacturer already done extensive testing? Why would you buy the pump before seeing if the factored fluid conditions are within testing tolerances?
Different case / impeller different performance maybe a different efficiency. Remember efficiency is only a number so it is possible for any number of pumps have the same efficiency.
Think you will find that most if not all pump manufactures will only guarantee pump efficiency on water under strict test conditions. Other liquors will be estimated only based on experience / tables etc. - the pump manufacturer has absolutely no control over application / installation / liquor properties. This becomes the responsibility of the end user.
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.)
J, I was trying to give a brief overview of the process of purchasing a pump, I skipped some details that I thought were common knowledge.
User - specify fluid conditions
Pump vendor - make preliminary pump selections (based on the actual fluid conditions) and quote to user
User - evaluate selections, pick one, purchase
Pump vendor - manufacture the pump, test with water, correct to actual fluid conditions, confirm it meets testing tolerances (confirm it passes test)
User - install and operate
Everything is on paper (or a computer) until the test results are in. Paragraph you quoted has nothing about a retest, the test is a test and that is why it is performed. It checks actual measured hydraulic performance vs the preliminary "on paper/software" information. It also confirms that vibration (and bearing temperatures when applicable) are acceptable.
Ok thank you 1gibson. It seems that a lot of the work done to match system specifications is work done my the pump manufacturer, not the person trying to buy the pump. The user simply sepcifies system conditions and works with the vendor to ensure that they get what they are looking for.
