turndown ratio metering pump

[fe2655847]

Hi experts,

Sorry for a rookie question.
Turndown ratio specified in the data sheet of 0.6. Pump manufacturer has specified 10:1. Is this acceptable? My understanding is that turndown ratio is pump manufacturer's capability, as long as the rated capacity of the pump is 110% more than maximum capacity. In this case, no minimum and max operating conditions specified in the datasheet only rated conditions. I think this is acceptable because the rated condition would be within the the guaranteed flow of manufacturer, ie between 10-100% setting. Thanks

 

[TD2K]

What do you mean by a turndown ratio of 0.6?

A turndown ratio of 10:1 for a metering pump is pretty common, it means the pump will cover a range from 1 unit/time to 10 units/time. As long as your requirements fall within the pump's minimum and maximum capacity limits it will do what you want it to do (assuming it will also develop the pressure you need, handle the viscosity, meet NPSHA, etc).

 

[fe2655847]

A turndown ratio of 0.6 is specified under the rated operating condition in the datasheet. That's confusing to me

 

[bimr]

Most metering pumps have a turndown ratio of 10:1,which simply means that the pump is within its accuracy rating anywhere between 10% and 100% of capacity.

The turndown ratio of 0.6 probably refers to a turndown of 60% of maximum capacity. Check with the specifier.

 

[JJPellin]

API specifies a standard down-turn of 10:1 for these pumps. That is the basis that most manufacturers use. However, some pump designs can pump accurately to a much lower value. If the adjustment includes stroke length and stroke rate, the combination can often go much lower. But, if the expected flow range falls with the standard 10:1, then you should have no problems whatsoever.

Johnny Pellin