Pucp
Materials
- Aug 6, 2001
- 32
Hi, I will like more about water pumps, because now I have to deal with them, I have read a lot but francly I have a lot of doubts. So I will appreciate a lot if you answer some of my questions:
1)How can I measure the NPSH - R in a new pump? Does I have to introduce friction losses and wait until the onset of cavitation and then measure the head at this point at the suction...the NPSH - R will be the difference between this head and the vapor pressure of the water?
2)How can I change the NPSH - A? can I introduce friction losses closing valves?
4)What happen if I put a valve before the suction of the water and after I start the pump with the valve complete open, I start to close it. Does it makes the friction losses increase? Does the flow changes?
3)What happen with both the NPSH - A and the NPSH - R if I increase the flow rate? Does the NPSH - A go down because of the friction losses increase? and does the NPSH - R goes up because of the same reason?
3)How can I change the head with the same flow rate? Can I introduce losses without changing the flow rate?
4)In what part of the system can I change the flow rate, at the final? with a valve?
5)Can you recommend me a book where I can find how to calculate the hydraulic forces in the impeller?
Again, I will appreciate your reply, I know that some of them will be so easy to you but for me are all the way around. Thanks in advance. Best Regards
1)How can I measure the NPSH - R in a new pump? Does I have to introduce friction losses and wait until the onset of cavitation and then measure the head at this point at the suction...the NPSH - R will be the difference between this head and the vapor pressure of the water?
2)How can I change the NPSH - A? can I introduce friction losses closing valves?
4)What happen if I put a valve before the suction of the water and after I start the pump with the valve complete open, I start to close it. Does it makes the friction losses increase? Does the flow changes?
3)What happen with both the NPSH - A and the NPSH - R if I increase the flow rate? Does the NPSH - A go down because of the friction losses increase? and does the NPSH - R goes up because of the same reason?
3)How can I change the head with the same flow rate? Can I introduce losses without changing the flow rate?
4)In what part of the system can I change the flow rate, at the final? with a valve?
5)Can you recommend me a book where I can find how to calculate the hydraulic forces in the impeller?
Again, I will appreciate your reply, I know that some of them will be so easy to you but for me are all the way around. Thanks in advance. Best Regards