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Dear all, I am involved in the upgrade of a rubber moulding press shop/Rubber plant in South Africa for an OEM pump company. The focus area is the press shop. Can anyone recommend a good rubber moulding press shop that I can benchmark internationally? Company is willing to pay for travel...

BigInch, What you are doing sounds quite awesome and even though I work for a pump manufacturer, were I to work for a process company I would also perform field tests of published curves simply because normally it is not that difficult to do and can save a lot of time and money should a problem...

That is perfectly correct BigInch. There is no reason for any of our customers to wish to operate a pump far off its design point. Anything less than 60% QBEP or greater than 120% is considered a no go area. This served as the basis for my reasoning that I could decrease the accuracy in the...

Hi to all those who helped me during my query on this thread. My apologies with the delay on my reply. I thought I would give you a concluding synopsis of what I had to do to fit these curves. My immediate involvement in the project is now finished and it has been a learning curve for me...

Hi electricpete Sorry for the delay and thanks for speaking to your pump engineer for me. I have spoken to few people who deal with alignment and so on and they also recommend 0.5 mils per inch. One of them is coming around to our factory within the next week or so to give an opinion, which I...

As you suggested I think I better be safe rather than sorry and have a good look at modelling the super critical region. I will also take your field experience of 0.5 mils per foot into account. The drawings for the shaft dimensions and specifications were developed by the company when...

Hi electricpete The application is high speed (between 1000 and 2400 rpm). The 1st lateral critical of the rotordynamic system is below 1000 rpm and the second critical is above 2200 rpm. So you are correct in that I must take into account dynamic bending. In this case the first mode shape of...

Thank you for the advice Tmoose. I am currently developing a runout specification for our shafts based on the G6.3 specification. To do this I will select three points on the shaft and a datum value. I need to figure out at each point what the maximum allowable runout can be in order to give the...

Hi all, Does anyone have information on manufacturing methods and specifications for rotating shafts operating in a process industry in order to minimize shaft run-out and vibration problems? The industry allowable vibration grade is G6.3 I believe. What I am interested in is the experience...

Just a quick afterthought; I have data for multiple curves for the same pump as each curve as given in Curve 1 represents data at a particular speed setting and typically I have between 4 and 7 speed settings per pump. Thus I could convert all my equations to a non dimensional form and that...

Hi again, I have been monitoring the conversation between electricpete and UmeshMathur. It is interesting to note the outcome of trying to fit integer polynomial order fits to data versus spline fitting. I have also been evaluating the data I have been given and comparing the results of the...

I definitely agree with you UmeshMathur. There is a lot of valuable information for me contained within your post. I am trying to persuade my company to take into greater account error when testing pumps, developing pump databases and publishing pump curves (something that they currently do not...

Thanks for giving me the link to www.systat.com. I am currently reviewing the software at the moment. In many ways it encompasses an automated version of the routine written out to me by electricpete. I agree with him in that the solver tool in excel is fairly powerful when utilised correctly...

Thank you all for your suggestions. I am planning to test one of our newer pumps this week and get as much data as possible (running the pump up and down the selected test curves) and then use that to tell me what type of curve fit seems appropriate. Hopefully with sufficient test data I should...

Dear all Can anyone tell me which curve fit is the best fit to use when working with head versus flow rate data and head versus efficiency data on centrifugal slurry pumps with a low specific speed (100-700 or so)? I am a Mechanical Engineer fresh out of university and am currently working...