Oil in water

[matbli]

I am pumping water that sometimes contains small amounts of oil, measured in ppm. Today I rely on my pump to not only pump but also emulsify the oil which I am analysing. But I would like to use a different kind of pump that is not mixing, therefore I wonder if this could be solved with some kind of static mixer. My flow is about 5 litres/. Any suggestions highly appreciated.

 

[ash9144]

I'm not sure I understand what you are trying to solve.
There are low shear pumps which would not mix the fluids as much, such as diaphragm.
There are in line static mixers which provide mixing. Usually some type of insert in the piping which cuts down on your open area for flow to increase velocity and vanes to redirect flow to provide mixing.
What exactly do you want to have when done? Sounds like you have a pump which is meeting your needs, so why would you change?

 

[matbli]

I am handling water with some times from limited down to very small, ppm, amount of oil in it. And I need this oil to be emulsified in order to detect it in a measuring cell of ours. In the present product we have a pump that solves this. But I am now working on a new product where I for different reasons want to use a diaphragm pump. I now the the mixing problem could be solved with a static mixer and I am looking for some suggestions about such products available.

 

[ash9144]

Best bet would be to contact some of your vendors for piping or valves. They would have in line mixers or know who would. Although I would be suspect of using one with a diaphragm pump since the dead time of the pump would allow some stratification of the oil. Not to mention the other problems created by a diaphragm pump.

 

[bimr]

One of the problems that you will encounter is that oil tends to stick and coat surfaces. Because of this, your oil-in -water measurements will err.

Suggest that you keep the piping distances as low as possible.

As to mixing, you will probably have to experiment a bit to find the best set-up since there are no tried and true method to accomplish what you are trying to do.

 

[GL431]

In some water-oil mixing processes a throttling valve is used to create a given pressure drop. The valve induces sufficient turbulence and shear forces to break up the water and oil phases into droplets small enough to allow intimate contact between the phases. I do not know whether this arrangment would work with a positive displacement pump. Perhaps a kind of variable orifice device which you can keep at a constant opening and which does not move around as the pressure fluctuations from the PD pump come through? A normal static mixer with the vanes redirecting the flow does not seem to be suitable for your purpose. I do not think that it would create sufficient turbulence and the shear forces needed to produce an emulsion.

 

[europipe]

Can't you put an oil separator in the suction of your pump?
Just a suggestion.