Then control based on the number of strokes, or time which ever is easier for you.   The diaphragm pump is not going to give you what you want.  Maybe you could fill an intermediate tank from the tote and then pump the whole intermediate tank into the reactor but that is more operator intensive.The air operated DD pump can work okay, if you use it to fill a charging cylinder from the tote, and then drain or pump the contents into the reactor.If your reactor dosage is small enough, you could use an air operated single stroke dispenser, e.g., air cylinder coupled to hydraulic cylinder, coupla check valves, etc.On some pumps like your average centrifugal, total head at the discharge of the pump is the pumps discharge head plus suction head. But on an average PD gear pump the suction pressure just lowers the hp required to do the job. When sizing an AOD pump the suction pressure is a positive. But AOD pumps do not like a pressurized suction. The diaphragms and there drive assembly parts are not designed for the higher pressure to be on the product side. Bent shafts and short diaphragm life is the result of high inlet pressure. You do not have high inlet pressure. I have AOD pumps that roughly meter chemicals into batch reactors. Some are directly equipped with solenoids and others with stroke counters that tie into a solenoid and allow you electronically control the number of strokes or the output of the pump. Most Reducing Valves large AOD pump manufactures have an option for batching electronics. To improve accuracy and assure that the check valves are seated properly you will need a back pressure valve on the pump discharge. This will also stop the siphon flow. If you want to try and use your flow meter you would want a surge suppressor between the pump and the back pressure valve. Your flow meter will not display accurately but it will be some what repeatable if the surges are suppressed. To regulate the pump through its air supply you can put a valve ahead of the pump to control the air volume which will control the pump speed. If the supply air can exceed the pumps maximum inlet pressure you would want a pressure regulator between the supply and the volume control valve. All of the advice given above is very good.  I just want to mention a few more variables.-- Diaphragm material affects the flow rate.  Teflon (+Neoprene backing) is more rigid, hence slower (and a lot more expensive) than Hypalon. Only use Teflon if your chemicals require it.-- Exhaust air muffler.

MORE NEWS