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Bit of guidance? design project

Hi guys I have a design and build project currently where I must build a cooling system, simply put its two boxes which contain water (tanks) connected to a pump which pumps water between the two boxes. I have basically got the system build and connected up with pipes/tubes to the pump between boxes etc. got the drainage system sorted out. Framework built. Electrical sensors currently in progress to measure water level and flow rate.
The big thing here is that I need to be able to control the flowrate and water level INDEPENDANTLY , and i cannot for the life of me work out how to do this. The flow rate control was easy just put in a tap/valve on the outflow and inflow of the pump which can be adjusted. However now i need to work out how to control the level of water in a tank. I did some thinking and thought of having like some sort of hollow plastic ball which would float in the tank normally, and attach JUST enough weight for it to sink to the bottom onto it. Then have a string on the top of the ball which goes through the lid and comes to the outside of the tank. Here we can add some counterweights which would make the ball rise up out the water and thus decreasing the water level. and the amount of weights on the string on the outside of the box would dictate how high oir low in the tank the ball is and therefore the water level in the tank.

however we have been told we need to be able to control the water level between 25-75 percent therefore the ball would need to be 50 percent the size of the tank am i correct? Im not asking you guys to do my work for me Im just really stuck at the moment and was wondering if I am heading on the right track or should I scrap this idea? I was wondering if this ball being moved in the tank would affect the flow rate out of the tank?

Reply 1

420haze

This is a drawing of the model so far, green indicates the taps/valves which can be easily turned to control the flow rate. Pink = all piping. In red is the pump, and tank 2 is higher up than tank 1 and just opposite it.

In reality we also have electrical sensors displaying the flow rate from the pump and water level in the top tank. Also we have a third tank that connects to both which is lower than both tanks , however this is just for drainage and during operation of the rig, the taps going to this drainage box will be off so I have omitted it from the diagram.

Now if it helps you understand the problem a little more, we will be told to set to X florwate whatever rate that may be, then told to adjust to water level in the tank without changing the flow rate (ie the flow rate must stay the same only the water level must change). So we cant just use the taps to make more water go in and less water leave if they were to ask ur to raise the water level for example. We need to be able to control between 25-75%. Any thoughts on my idea above? was told we would need a physical mechanism in the tanks to do this hence why i thought of the plastic ball + weights to displace the water?