multisatage pump

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sandeep lokhande Power-User Join Date: Jul 2008 Location: India Posts: 452	multisatage pump 08/25/2008 5:45 PM
	i have two multisatge pump one pompetravini make head 12 meter and flow-4m3/hr 5-stage speed-1400 kw-4 another aoli make head 12 meter and flow -4m3/hr 8-stage speed-2900 kw-3 if we put aoli make pump in place of pompetravini, its get tripped and showing high pressure on gauge does the stages and rpm creating problem __________________ thoughts becomes things.
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#10 "Re: multistage pump" by The Prof on 08/27/2008 9:01 PM (score 2)

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#7 "Re: multistage pump" by The Prof on 08/27/2008 2:19 AM (score 1)

Anonymous Poster	#1 Re: multisatage pump 08/25/2008 6:08 PM
	Does it trip on high pressure or high motor load?
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Steve S. Guru Join Date: Aug 2007 Posts: 1790 Good Answers: 87	#2 Re: multisatage pump 08/25/2008 7:06 PM
	What is the NPSHR and for each of the pumps? And what is the NPSHA? The curves are obviously different between the two as they are running at different speeds and with different staging... What exactly is tripping the pump, and what gauge are you showing high pressure on? I think your suction pressure is too high for the faster pump... but I have not really thought it through...
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Hendrik Guru Join Date: Jan 2007 Location: Centurion, South Africa Posts: 3921 Good Answers: 97	#3 Re: multisatage pump 08/26/2008 2:00 AM
	If you run the slow pump at a higher speed it will show high pressure and overload. It may even overload at almost closed valve. __________________ Never do today what you can put of until tomorrow - Student motto
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sandeep lokhande Power-User Join Date: Jul 2008 Location: India Posts: 452	#4 In reply to #3 Re: multisatage pump 08/26/2008 6:08 AM
	its a new pump came with motor we not changed motor for high speed is it possible same flow and head pumps could give diff pressure and npshr ornpsha how can i understand tripping cause of pressure to get pressure is it possible to throttle suction valve or discharge valve please advice me __________________ thoughts becomes things.
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user-deleted-1104 Power-User Join Date: May 2007 Location: Parallel 45 Posts: 226 Good Answers: 21	#5 In reply to #4 Re: multisatage pump 08/26/2008 6:47 AM
	Hello Don'n throttle the suction valve. You will get cavitation. Assume the system has two separate suction lines for each pump, you could start in paralell both pump, start to open a little bit each discharge pump valve, try to keep the flow over the minimum continuous flow for each pump and in this way perhaps can get a balance point for parallel operation. Don't forget to observe the pressure while this test. Another way, if you have, is to get a operation point viewing the pump curve versus system curve. __________________ Look over to the next challenge
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Hendrik Guru Join Date: Jan 2007 Location: Centurion, South Africa Posts: 3921 Good Answers: 97	#6 Re: multisatage pump 08/26/2008 5:23 PM
	Hi sandeep A 3kw tripping the power where a 4kw did not - something else must be wrong. Maybe you should check everything. Electricity supply and connections. Pump curves if you can get it. Design flow and pressure. Pipe system. What are you pumping? Starting procedure? Was the system primed when you started? Is this centrifugal pumps? __________________ Never do today what you can put of until tomorrow - Student motto
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The Prof Guru Join Date: Aug 2006 Location: Western Australia Posts: 767 Good Answers: 58	#7 Re: multistage pump 08/27/2008 2:19 AM
	Sandeep, if you give me the pump model I can probably be more specific, but assuming that this is an Aoli type ALD then the pump designation will tell you what you have, and I would guess that the third number in your type is 12, which means that it is 12 m head per stage. (They do not make one with a head per stage of 1.5 meters as far as I know). I find it very hard to believe that you have a pump with 8 stages turning at 2900 rpm and only developing 12 meters head. You could probably develop that head without the impellers. If this is 12m/stage then it should not be a surprise that it shows high pressure and trips a 3 kW motor. __________________ If you can't explain it simply, you don't understand it well enough. (A.E.)
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sandeep lokhande

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#9
In reply to #7

Re: multistage pump

08/27/2008 5:50 PM

The way you suggest me i checked both the pump details in manuals. there was original motor 3kw on pumpetravini but our electrician put which is available 4kw.

the details of pump are as bellow

Details of pump

DETAILS	POMPETRAVINI	AOLI
MODEL	TBH 292/1-C/A3	25GDL4-11*8
FLUID TYPE	CAUSTIC SODA	CAUSTIC SODA
DENSITY KG/M3	1450	1450
VISCOSITY	15-40	15-40
OPRT. TEMP	30	30
FLOW	750 L/HR	2808 L/HR
HEAD	61.2 M.C.L.	96 M
NPSHR	1.5	1.4
RPM	1450	2900
KW	3	3

What is suction head coz?

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The Prof Guru Join Date: Aug 2006 Location: Western Australia Posts: 767 Good Answers: 58	#10 In reply to #9 Re: multistage pump 08/27/2008 9:01 PM
	Sandeep, the figures that you have now given are completely different from the ones in your original question. We have no insight into the system in which this pump is installed, but you need to be aware that Hydraulic Power is directly proportional to flow and by your figures the Aoli pump will require about 3.7 times as much power at the same differential head as the other pump. The pump type you give is 25GDL4-11*8. This means a vertical multi stage pump of capacity 4 m3/hr, 11m head per stage times 8 stages which is 88 m differential head across the pump. Power required is 3 kW __________________ If you can't explain it simply, you don't understand it well enough. (A.E.)
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Steve S. Guru Join Date: Aug 2007 Posts: 1790 Good Answers: 87	#11 In reply to #10 Re: multistage pump 08/27/2008 9:30 PM
	Good answer Prof..
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2ndthot Associate Join Date: Jul 2008 Posts: 29 Good Answers: 1	#8 Re: multisatage pump 08/27/2008 5:11 AM
	just a thought . . . does the two line has the same available suction head? for sure the two pump have different size and dimentions of impeller(different manufacturer different design) . . .. better check the suction head coz it has a great effect to its discharge head which is shown by the pressure gauge in the discharge.
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