Need some help on air pressure through a manifold and optimal leak/pressure rate

[pityocamptes]

I have a small pump system for an aquarium, and have decided to build a small manifold. The total volume of the manifold and the tubing is 2.9828 cu inches. Here is my pump specs:

Inflation time < 8s (from 0-200 mmHg in a 100cc tank)
Air flow > 70mL/min
Max pressure > 360mmHg
Leakage max 36mmHg/15sec from 300mmHg at 70cc tank
Pump time - 7sec on / 7sec off


From the pump is a 3/16" x 12" tube (volume = .3311 cubic inches) which attaches to a small cylindrical manifold (1"x3" - volume = 2.3571 cubic inches) that has two air rails (each air rail (1/4" x 3" -volume = .2946 cubic inches). Total volume should be 2.9828 cubic inches.

I was hoping to see if someone could figure out how big of an orifice I would need on each rail for maximum pressure, within the 7 seconds on, 7 seconds off (basically optimal orifice pressure and size where manifold drops stays at a constant positive pressure at the end of the 7 second off phase wherein the 7 seconds on phase starts to pump and build pressure. Any help on this would be appreciated. Thanks.

 

[pityocamptes]

Anyone? Bump...

 

[pityocamptes]

No one? Thats odd. I guess than, I will just have to experiment with different orifice sizes to get the best result, was trying to avoid this and wanted to see if a mathematical solution existed for this problem.

 

[jakestenson]

Here's some information about orifice calculations. Hope this helps.

 

[PJC01]

Based on the information provided, it seems that the main concern is achieving optimal pressure and minimizing leaks in the system. To determine the optimal orifice size for the air rails on the manifold, a few factors need to be considered.

First, the maximum pressure that the pump can achieve is 360mmHg, and the leakage rate is 36mmHg/15sec. This means that the maximum pressure that can be maintained in the system is 360mmHg - 36mmHg = 324mmHg. Therefore, the orifice size should be small enough to maintain a pressure of 324mmHg during the 7 seconds off phase.

Second, the total volume of the manifold and tubing is 2.9828 cu inches. This means that during the 7 seconds on phase, the pump needs to be able to fill this volume with air. Since the pump has an air flow of 70mL/min, it can fill 2.9828 cu inches in (2.9828 cu inches * 16.387 mL/cu inch) / (70 mL/min) = 0.68 minutes, or 41 seconds. However, the pump only runs for 7 seconds on, so the orifice size should be large enough to fill the manifold in 7 seconds.

Based on these considerations, the optimal orifice size would be one that can maintain a pressure of 324mmHg during the 7 seconds off phase and can fill the manifold in 7 seconds during the on phase. This will likely require some trial and error, as the optimal orifice size will depend on the specific characteristics of the pump and the manifold.

Additionally, to minimize leaks, it may be helpful to use high-quality tubing and ensure that all connections are secure and airtight. Regular maintenance and checking for any leaks can also help to maintain optimal pressure in the system.