What are common control strategies for dosing pumps?

Question

Dosing pumps means pumps that dose a specific amount with a high accuracy. In many process control scenarios, level gauges or flow meters are used (with low accuracy, at least in some cases), what other strategies are widely used? Sources/Examples would be appreciated.

Edit 2012-07-19
My questions are, what measurements are taken (if any), how are the diverse inexactitudes accounted for and where along the drive train do you control the pump (FI-controlled motors vs. just turning off after Volume X is pumped, for example) I can imagine a lot of ways to do this, but I don't know why one way may be superior to another in a given situation.

Answer 1

There are thousands of ways and products to mix fluids and gases , titration pumps, pulse pumps digitally controlled, radial pumps, bubble control pumps for gases & medical, consumer, industrial, military, aerospace for many industries.

Basic designs include;

1. Rotary pumps => Consumer: Aquarium version shown here

2. Reciprocating Style Metering Pumps =>

   • displacing a fixed volume through the reciprocating motion using;
   • a piston, a diaphragm, or a bellows

3. Liquid Diaphragm Pumps ( like those used in fuel pumps )

4. Diaphragm Liquid Metering Pumps ( discontinuous pulsed operation, including those with magnetic drive)

5. Electronically Controlled Diaphragm Metering Pump ( more precise with flow sensing )

6. Pulsed syringe mixer with rate and cc. pulse control

Can you articulate your requirements in more detail? Got Specs?

Answer 2

I don't believe many medical infusion pumps use any volume or flow feedback. They are built to very tight specs, have very precise instructions for use, and are calibrated. I know this to be the case for the one or two I've had opened up in my hands. I don't know about syringe pumps but I wouldn't be surprised if they had position encoder feedback.

Answer 3

Try search for chemical dosing pump. They are widely used by PCB manufacturers.