Water pressure in multiple tanks

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Discussion Overview

The discussion revolves around the behavior of water draining from multiple stacked tanks connected to a single downpipe with one-way flow valves. Participants explore which tank will drain first when a tap at ground level is opened, considering factors such as pressure and valve operation.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions whether all tanks should drain at the same rate.
  • Another participant raises a query about why water does not flow from higher tanks to lower tanks when the tap is closed, suggesting a siphon effect.
  • A suggestion is made to use an illustration to clarify the connections between the tanks.
  • One participant asserts that the top tank will drain first, as the tanks below would refill from the tank above if their levels decrease.
  • After additional context is provided, it is noted that all tanks are full and connected to a single downpipe with one-way flow valves, which prevents water from flowing between tanks.
  • Another participant proposes that the pressure from the highest tank would cause it to drain first, suggesting that the check valves may be unnecessary.
  • It is explained that the one-way valves will not open until the pressure outside the valve is lower than inside, indicating that the top tank drains first, followed by the water in the pipe above the second tank, and then the second tank itself.

Areas of Agreement / Disagreement

Participants express differing views on the mechanics of the draining process, particularly regarding the role of pressure and the function of the one-way valves. No consensus is reached on which tank will drain first under the described conditions.

Contextual Notes

The discussion is limited by assumptions about the behavior of the one-way valves and the specific configuration of the tanks and downpipe. The impact of pressure dynamics and valve operation remains a point of contention.

eocbusy
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hi - i am new so forgive any errors.
question is this. if a number of water tanks are stacked one on top of the other. and each share the same downpipe with a tap at ground level. When the tap is opened which tank will drain first and why?

many thanks.
 
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shouldn't they be drained at the same rate?
 
In the initial state with the tap closed, why isn't water flowing from the higher tanks into the lower tanks like normal siphon process?
 
i think u should use an illustration to show how are the tanks connected
 
The top tank will drain first, since the tanks below it would be refilled from the tank above, were their levels to go down.
 
thanks for replies so far. but clearly i have not given enough info.
the tanks are all full. they are each connected to a single downpipe. Each connector has a one way flow valve. so water cannot flow from one tank into another. in that scenario when the tap at ground level is opened all the tanks will compete to discharge their volume. i would just like some guidance on which would empty first. and of course why. t

thanks again.
 
I think the pressure from (on?) the highest tank would cause it to drain first as that pressure would keep all your lower check-valves closed. In fact I would hazard to go further out on the limb and say that the check-valves are superflous.
 
The one way valves will not open until pressure outside the valve is lower than pressure inside the valve, so until all water above any current tank's water level is drained, the valve for that tank will not open. The top tank drains first, then the water in the pipe above the 2nd tank drains next, then the 2nd tank and water in the pipe just below level of water in 2nd tank drains, ...
 

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