Water Tank Overflow Air Piston concept/question

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Discussion Overview

The discussion revolves around determining the minimum piston weight or force required to push air from an air tank into a supply tank, which would then purge water through a discharge pipe. The context includes considerations of gravity-fed systems, pneumatic principles, and the mechanics of fluid dynamics, with a focus on theoretical calculations and practical applications.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant seeks to calculate the minimum piston weight needed to push air into a supply tank to purge water, assuming no friction loss.
  • Another participant questions the application and initial thoughts on calculations, prompting further clarification on the system's design.
  • Several participants discuss the feasibility of using direct piston weight versus air pressure to achieve the desired water movement.
  • There are calculations proposed regarding gravitational potential energy (GPE) and the work done by the piston, with suggestions to consider the energy changes involved.
  • Participants explore the relationship between piston weight, air pressure, and the resulting force needed to lift water through a discharge pipe.
  • One participant raises concerns about the efficiency of compressing air and the implications of heat generated during compression.
  • Discussions include the pressure calculations based on piston area and force, with questions about how pressure is transmitted through the system.
  • Participants engage in calculations regarding the pressure needed to overcome the weight of the water column in the discharge pipe.

Areas of Agreement / Disagreement

Participants express differing views on the efficiency and mechanics of using air pressure versus direct piston weight to achieve the water purge. There is no consensus on the optimal approach or the calculations involved, as various models and assumptions are discussed.

Contextual Notes

Limitations include assumptions about frictionless systems, the dependence on specific definitions of pressure and force, and the unresolved nature of certain calculations regarding energy changes and flow rates.

Who May Find This Useful

Individuals interested in fluid dynamics, pneumatic systems, engineering design, and those exploring gravity-fed mechanisms may find this discussion relevant.

  • #31
Hi Russ sorry for the delay. It can, but not by any major scale, so we are stuck.

But, could you confirm my calcs below IF we were to pump air from a compressor into the supply tank to force the water up the pipe:

Assume we need min 20 psi min
Tank volume is 279 cu ft
Air is incompressible

Compressor specs (values taken from commercial comp online)
PSI40
CFM @ 40psi15.4
Volts230
AMPS25
Time to fill Supply Tank (mins)6
Power (watts/hour)5750
KWh used0.61

So it would take the above compressor 6 minutes at 40 psi to fill the supply tank and purge the water up thru the outlet line ?

I know there will be issues with some water not being able to purged, but the overall volume should be using these values correct ?l
 
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  • #32
And I get the min 20 PSI from the weight of the water in the column/the column area (279 lb/12.2 sq in), and used a 40 psi compressor value to account for compression of air etc
 

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