I need help automating a process we have done by hand over the past few years. We need to "spray" tap water into a material mix at different rates. The typical volume of water applied ranges from 25 ml to 1000 ml. The typical flow rate should be approximately 100 ml per minute. The accuracy does not need to be that great, probably less than 5%.
We have done this in the past using an approximately 15 psi pressurized clear plastic column filled with water having a scale affixed. We would turn the valve on and off manually after monitoring the volume change on the scale.
I need to automate this process with user defined volumes of water applied. I have very little experience with control systems and am looking for as close to "off the shelf" as possible.
I had thought of using a flow meter and a timer hooked to a solenoid. If I knew the flow rate I could calculate the time to achieve the desired volume and set the timer to activate the solenoid when the calculated volume has passed. But I would need to add a regulator to verify the psi applied to the system is always the same.
I also have thought of using a micro totalizer to do the same job but I don't have any experience with these devices.
But I basically need a technician to enter the volume in ml and hit start. Any ideas on how I can accomplish this task economically?