Flow inconsistence

[Thuba]

l have a pump rated at 4m3/h and 35m head. lt pumps edible oil through an economizer and the to dearator with some nozzles. From the dearator there is another pump feeding a vessel (rated 9m3/h and 40m head) and there is a flowmeter reading 1800L/h (1.8m3/h). Some how the dearator gets empty or starved with oil. My question is how so as the dearator pump is just pumping 1.8 m3/h from the dearator, while the one feeding it is feeding at a rate of 4m3/h. see attached schematics

 

[HTURKAK]

how so as the dearator pump is just pumping 1.8 m3/h from the dearator, while the one feeding it is feeding at a rate of 4m3/h.

IMO ,the answer is simple . The capacity of pump 101 could be 4 m3/hr but still the flow is less than 1.8 m3/hr or the flow is more than 1.8 m3/hr.
I will suggest you two alternatives,
-provide frequency converter for pump 102 modulated with the oil level at the deaerator.
- check if possible to lift the deaerator above the vessel and delete pump 102
You may also consider to provide more details to get better responds

 

[EdStainless]

I take that all of your flows and heads have been corrected for SG and viscosity.
I agree with HT, you are either not getting 1.8 out of 101 or the measured flow is wrong.

 

[LittleInch]

This is why you don't double post. There are some similar replies in the chemical forum.

This was mine

What type of pumps are these?

PD type pumps will generally pump at a fixed flow, +/- 10%.

Centrifugal pumps generally provide a fixed differential head +/- 15% from your duty point.
T
The duty point flow is only one point on a curve. What flow you actually get is dependant on your downstream frictional and head losses.