Acceleration head loss of flexible hose

[Wkcoo]

Hi all, regarding diaphragm pump suction acceleration head loss, the estimated formula is Ha=LVNC/gK. Does this formula apply to flexible hose as well? A vendor is supplying a temporary pump skid for chemical injection, and suction piping is made of 10m long 1" dia. steel braided flexible hose to run 5000 litre per hour. I am concerned because if evaluated using formula above, we would need a 2" hose to avoid cavitation. I read somewhere online that installing flexible hose on suction will help reduce the acceleration head term but can't find any quantitative info. If flexible hose helps, how effective and how much acceleration head does it reduce (10%?50%?90%)?

 

[1503-44]

Never heard of that and can't see a reason as to why it would work. There might be some advantage if the flex was very significant, where it would tend to constrict with the pulsations with some delay action, blood vessels tend to do the same, but you would not catch me relying on that. I wouldn't think there would be much help if any. I think blood vessels do that because bio-braded steel would have been a difficult evolutionary step to accomplish.

Give the supplier a call. Tell him that you have proof that 10m of 1" is not sufficient and he must supply 2", or calculations that 1" will be OK and full cost repair and replacement, if it fails within the pump's warranty period.

 

[bimr]

Don't know where you read that. Acceleration head loss would also be termed resistance to flow which is exactly what you don't want when you are pumping.

Hoses have horrible fluid characteristics if you are trying to pump. Since there is no standard hose size, the fluid flow properties have to be determined empirically by the manufacturer. You will have to obtain that information from the particular hose manufacturer.

Pulsation dampeners were invented to fix the pumping problems associated with positive displacement pumps.