Air pressure and water height vs valve operation time

In summary, the conversation discusses the speaker's plan to build a small water tank with two tubes for outtake and air intake, and their goal to control the amount of water expelled from the tank using a timed valve. The speaker also mentions their knowledge of the ideal gas law and their doubts about the complexity of their plan. They suggest using a positive displacement piston pump or a syringe for a more accurate and calibrated method.
  • #1
MrCedgy
3
0
Ok, so I am trying to build myself a small water tank (about 1 L) with 2 tubes coming from the top. The first one goes all the way down to the bottom (thus in the water) and acts as the outtake. The second one is an air intake where the air pressure is regulated, say 5 psi. Now, I want to be able to time the valve regulating the air intake so as to control the amount of water expelled from the tank (for example, I could want to expel 300 mL).

I know from my classes (I am a future mechanical engineer who freshly started his degree) that the air pressure to maintain a water column of height 'z' to be P=z*rho*g, which would also be equal to (n*R*T/V) by the ideal gas law.

Now, my hunch is that in order to time the valve, I need the number of moles of air that goes from my compressed air to the water tank every second, which could be evaluated from the pressure difference.

The main reason I am doubting myself is because I am pretty sure there is an easier way to deal with this, especially since my air pressure is normalized.

If you need any clarification, I would be happy to oblige!

Have a nice day!
 
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  • #2
Allowing air in the tank makes it unnecessarily difficult.

Water is incompressible. If the tank contains only water, it is much easier. To expell 300 ml of water, inject 300 ml of water.

The best way to do that in a calibrated fashion is with a positive displacement piston pump. In your case, I recommend a syringe.
 

1. How does air pressure affect the height of water in a container?

Air pressure directly affects the height of water in a container by exerting force on the surface of the water. As air pressure increases, the force on the surface of the water increases, causing the water to rise. Conversely, as air pressure decreases, the force on the surface of the water decreases, causing the water to lower.

2. What is the relationship between water height and valve operation time?

The relationship between water height and valve operation time is dependent on the type of valve and the water pressure. In general, as the water height increases, the time it takes for the valve to open or close also increases. However, this relationship may vary based on specific factors such as valve design, water pressure, and flow rate.

3. How does air pressure affect the operation time of a valve?

Air pressure affects the operation time of a valve by influencing the force needed to open or close the valve. As air pressure increases, the force required to operate the valve also increases, resulting in longer operation time. On the other hand, lower air pressure will require less force, resulting in shorter operation time.

4. What is the significance of understanding air pressure and water height vs valve operation time?

Understanding the relationship between air pressure, water height, and valve operation time is crucial for many industries and applications. For example, in water distribution systems, it is essential to maintain proper air pressure to ensure consistent water height and valve operation time. Additionally, this knowledge can help in predicting and preventing potential malfunctions in valves, which can save time and resources.

5. How can air pressure and water height be controlled to optimize valve operation time?

To optimize valve operation time, air pressure and water height can be controlled by adjusting the air pressure in the system. By maintaining consistent air pressure, the force on the water surface will remain constant, resulting in consistent water height and valve operation time. Additionally, regular maintenance and proper valve design can also help to optimize valve operation time.

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