annu777
Mechanical
- Apr 2, 2013
- 5
Hi to all,
I would like to ask about the parallel pumps how work it out,
we have chilled water pump rated at 2400 gpm at 150 feet head, eff.=84%, RPM 1785, Power Motor 150 Hp (380/3/60), centrifugal hor. split case type.
If the parallel Chilled water pump run at 72% each then the the output registered flow-meter reading at 139.42 Lps (2211 gpm).
Question;
1. The reading of the flow-meter near the actual possible reading? The flow-meter not calibrated since the plant installed a ten years ago.
2. I always argued with my boss about this matter he said that the total flow of the pump as the fluid flow Qin = Qout, 72% of 2400 gpm = 1728 gpm each pump but he said the total flow is equal the sum of two sum directly its is correct? or in actual its will decreased because of the compressing of the fluid,
i read some article that they said;
Pumps in Parallel - Flow Rate Added
When two or more pumps are arranged in parallel their resulting performance curve is obtained by adding their flowrates at the same head as indicated in the figure below.
Centrifugal pumps in parallel are used to overcome larger volume flows than one pump can handle alone.
for two identical pumps in parallel, and the head is kept constant, the flowrate doubles as indicated with point 2 compared to a single pump
Note! In practice the combined head and volume flow moves along the system curve as indicated from 1 to 3.
point 3 is where the system operates with both pumps running
point 1 is where the system operates with one pump running
In practice, if one of the pumps in parallel or series stops, the operation point moves along the system resistance curve from point 3 to point 1 - the head and flow rate are decreased. see attached image.
I would like to ask about the parallel pumps how work it out,
we have chilled water pump rated at 2400 gpm at 150 feet head, eff.=84%, RPM 1785, Power Motor 150 Hp (380/3/60), centrifugal hor. split case type.
If the parallel Chilled water pump run at 72% each then the the output registered flow-meter reading at 139.42 Lps (2211 gpm).
Question;
1. The reading of the flow-meter near the actual possible reading? The flow-meter not calibrated since the plant installed a ten years ago.
2. I always argued with my boss about this matter he said that the total flow of the pump as the fluid flow Qin = Qout, 72% of 2400 gpm = 1728 gpm each pump but he said the total flow is equal the sum of two sum directly its is correct? or in actual its will decreased because of the compressing of the fluid,
i read some article that they said;
Pumps in Parallel - Flow Rate Added
When two or more pumps are arranged in parallel their resulting performance curve is obtained by adding their flowrates at the same head as indicated in the figure below.
Centrifugal pumps in parallel are used to overcome larger volume flows than one pump can handle alone.
for two identical pumps in parallel, and the head is kept constant, the flowrate doubles as indicated with point 2 compared to a single pump
Note! In practice the combined head and volume flow moves along the system curve as indicated from 1 to 3.
point 3 is where the system operates with both pumps running
point 1 is where the system operates with one pump running
In practice, if one of the pumps in parallel or series stops, the operation point moves along the system resistance curve from point 3 to point 1 - the head and flow rate are decreased. see attached image.
