Water bridge priority problem

[Sturm58]

Hi guys.. can someone explain to me what am I doing wrong?

Should polluted water not always take priority on this bridge? 

This is making me crazy!

 

[Nogard78]

Well yes but actually no. Since water sievie takes 5kg/sec, 5 kg of normal water stay at the end of the bridge and are refilled by the bridge, and since you have flow of less then 5kg of polluted water it will always result in this situation. I think that connecting this bridge AFTER water sieve would be better.

Something like that:

 

[blakemw]

The reason this does not work is because bridges will merge packets at the output, so unless the water packet is completely removed it keeps getting refilled by the bridge and so a polluted water packet can never enter that pipe.

So in short bridge priority does not work if you are dealing with two different kinds of liquid. As Nogard said, you should use the bridge priority into the clean water output, so you aren't mixing liquid types.

The best solution for this case has already been giving, but it's worth noting that most outputs do not merge packets, the packet merging behavior is specific to Bridges and ordinary (non-meter) Valves. Shutoffs, Meters and pretty much any other building with an output do not merge packets at the output and actually require an empty pipe in order to deposit a packet into, and so for those buildings the priority scheme actually would work, it just doesn't work for Bridges and Valves. In cases where it's important to avoid output merging a Shutoff or Meter can be a good solution, for instance say you want to fill a loop with 1000 g/s of liquid to avoid phase change in pipes, a Valve can't (trivially) do this because it'll merge packets, resulting in 2000 g packets (then bigger). But a Meter Valve can trivially do this because it never merges packets so the loop will be perfectly filled with 1000 g packets.

 

[psusi]

Why are you trying to feed fresh water to the sieve when there isn't any polluted water?