Better Dosing

[rmayer]

Hello,

I have been using a dosmatic fluid driven doser to add 2.5% of additive to a 1 gpm stream. It sufficed for the initial proof stage but now we need to spec something a little more permanent, reliable, and if possible feedback fault detectable by PLC. What methods would anyone recommend to dose in the concentrate and why.

BTW, our current fault detection on the dosmatic includes a vacuum pressure transducer on the pickup counting suction pulses and a down stream conductivity sensor measuring net EC.

 

[eadwine]

Have you thought of using an eductor (jet pump)utilising the energy of flow from the motive fluid to entrain the additive. We use these all the time to inject and dose fluid streams. They come in all sizes for dosing applications utilizing a suction side orifice to regulate additive quantity. As for manufacturer's try Penberthy. There is a company that produces small ones specfically for low volume dosing, but the name escapes me at present.

As for monitoring, any required instrumentation can be installed.

Advantages: no moving parts or metering pumps that have to be constantly adjusted and fussed with.

 

[jmw]

I'd suggest that in final you would measure the flow stream and measure the additive.
Data log for QA.
Additive can be metered using coriolis or US meters which specifically target the dosing world.
(Yes, Micromotion for coriolis or TDI for US).
Instead of dosing the additive as a shot every so often you can add as a continuous flow stream.
Some very low flow rate gear pumps with variable speed control which can be controlled using a PID controller that uses the main fluid flow as the master stream measurement.



JMW

http://www.ViscoAnalyser.com