We did run at BEP for a time in 2013 and still had the problem. The average vibration was lower but the peak still happened in the temperature band. Lots of great suggestion and more to investigate. You are wise and experienced. I appreciate all you have contributed. We will keep in touch...
Thanks good suggestion. The units are metric m3/hr,m. Yes corret at about 107%. Time for bed now. Get up at 4:30. Talk more later I hope. We have work to do and gather more data.
Thanks,
Thanks. My feeling is the pumping system design should deliver what the process demands at the greatest efficiency not the other way. The tail should not wag the dog. Little confuse how do you change the specific speed without change the impeller?
What I am saying is our reactor turn around is every 30 hours and we move through this temperature band fairly quickly. If we shift the problem to the 280 degree C area it would be a larger problem because that is where we normally operate at for the thirty hours. 280 to 300.
Understood. We have a great vibration technician/engineer. We can collect all the peak view data. I will pass this on to him. I was a little concerned about changing the vanes as a solution. Could it just shift the problem to a different temperature band, frequency and see the same problem...
I feel the ODS would be a good next step. I will look into the bearing bracket. Sounds like you really work with some awesome pumping systems. Specific suction speed is 12000. Really appreciate your input.
Thanks everyone. The impeller redesign was discussed with the vendor early on and is still on our possible root cause list. It is one of the more difficult items to act upon. The impeller would have to be designed, a casting made and machined. The pump would have to be sent back for API 610...
Thanks can you give more detail on the fluid pumped and type of pump? Sounds very similar to our situation except we are single stage double suction. And your vibration went away once above the slot temperature too?
Thanks much for sharing. This has been quit an enlightening experience the last couple years. I am feeling more confident that we moved down the logical path and now just need to get to the end.
Three different pumps with all the same results and the vibration pretty much in the same temperature band within a few degrees C. We are very vigilant about our measurements and document them. I believe different heat transfer fluid would be last for expense and envirnmental reasons. Found a...
This pretty much puts us on the same page. We did make a modification to the volute lips cutting them back to the 168 deg angle with some improvement on the peak vibration seen. 20 mm/s before vs 9 mm/s now but not sure if it was this modification or increasing the piping suction diameters...
Root cause we have worked on or eliminated.
1. NPSHa too low. Calculation work fine and the vibration improves even as the temperature and vapor temperatuer increases.
2. Impeller six vanes and cut water splitter. Have modifiec the cutwater splitter profile and reduced impeller size to 410mm...
I have a very unusual pumping system. It is a closed loop hot oil system, (Syltherm 800) being pumped by a Gould's 3620 API 610 between the bearing pump at 2975 rpm, 2250 m3/hr. The pump starts from ambient and is heated to 300 deg C. The flow is maintained constant. Is part of a...
