We are just beginning a new project to design a training system on controlling the flood up in a dive chamber. The actual system has a hand control valves to control the rate of flooding in a chamber. To simulate this system we have decided to have tank (more like a pipe with end caps) that gets filled and has our flow monitoring devices. This tank will be connected to a sight glass where the user will view and control the level of flow in the tank. The flow will need to be controlled quite precisely, and the maximum flow rate will be about 4 gpm. Due to the nature of the original system, our trainer will use a series of dummy valve controls that are rotary encoded back to a computer. The computer will then analyze the position of the various dummy valves and output values to the control system for the control of the flow. My question is in regard to the overall system. With these level of flow rates what is the best method to accurately control the flow into and out of the tank. Would it be best to use a constant speed pump with a computer regulated control valve, or would it be better to use a variable speed pump? I have had good results in two past projects where precise flow control was necessary, using a variable speed pump, but I have never used electronically controlled valves. Can you get very precise control using control valves? What are the types of valves that are available for flow control of this type, and what manufacturers are recommended?
Thanks, Mike D.