#### Asisraja D

##### Mechanical

Hi professionals

We have planned to install flow meter for our RO water header lines but we are facing the flow range issue while selecting the flow meter.

Our pump capacity is 30 m3/hr (or) 30000 Liters per hour and pump head is 30 meters. we need to install this for 1 1/2" (40NB) line and 2 1/2" (65NB) line.

we have selected the metal tube rota meter for our application in this but the problem is for 40NB line they provide only 500 - 5000 LPH flow range and for 65NB line it is 1600 - 16000 LPH. why this much of variation in flow range for both sizes ? we need to measure the maximum flow rate of the pump as 30 m3/hr ?

is this possible in these two pipe sizes (40NB,65NB) ? As per vendors suggestion we could not achieve this much of flow rate in these sizes.

i will upload the vendors quotation here. can anyone please tell me why can't we achieve this flow rate ? As per Q=AXV when the pipe area reduces the velocity will increase so if we reduce the pipe area absolutely velocity will increase and same we calculated the head loss and it is very minimum range in 65NB pipe but huge head loss in 40NB line ? My doubt is due to huge head loss how can i calculate the flow rate in the 40NB line ? because then only i can select the flow range for flow meters. The pipe MOC is SS-304 ASTM grade A312.

i attached my pressure drop calculation here and vendor quotation please review when you have a free time.

Thank you all.

We have planned to install flow meter for our RO water header lines but we are facing the flow range issue while selecting the flow meter.

Our pump capacity is 30 m3/hr (or) 30000 Liters per hour and pump head is 30 meters. we need to install this for 1 1/2" (40NB) line and 2 1/2" (65NB) line.

we have selected the metal tube rota meter for our application in this but the problem is for 40NB line they provide only 500 - 5000 LPH flow range and for 65NB line it is 1600 - 16000 LPH. why this much of variation in flow range for both sizes ? we need to measure the maximum flow rate of the pump as 30 m3/hr ?

is this possible in these two pipe sizes (40NB,65NB) ? As per vendors suggestion we could not achieve this much of flow rate in these sizes.

i will upload the vendors quotation here. can anyone please tell me why can't we achieve this flow rate ? As per Q=AXV when the pipe area reduces the velocity will increase so if we reduce the pipe area absolutely velocity will increase and same we calculated the head loss and it is very minimum range in 65NB pipe but huge head loss in 40NB line ? My doubt is due to huge head loss how can i calculate the flow rate in the 40NB line ? because then only i can select the flow range for flow meters. The pipe MOC is SS-304 ASTM grade A312.

i attached my pressure drop calculation here and vendor quotation please review when you have a free time.

Thank you all.