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enter image description hereMy target is to create a valve with multiple inlet capillaries. And my output is a pipe of a larger diameter. I do not want to use any electrical systems, and at the same time, I want to maintain enough negative pressure inside the valve to influence the flow of fluid to be from capillaries to the pipe and not the other way round. The pipe-capillary system is evacuated and the fluid inside is at a higher than atmospheric pressure (we can assume 4-5 atm). I also wish the flow to remain laminar and avoid turbulence.

I looked into kinds of pumps which, in principle, achieve this... But I could not find any self-controlling system which does not require external power to maintain the pressure force required. Pneumatic systems like the flow valve looked promising but I could not figure out a way to achieve the requirement I am aiming for. I was thinking of inserting a high pressured section inside the valve which would push a diaphragm with constant force. And that force can be used to maintain the negative pressure that I want. Another idea with having a vacuum instead of a high-pressure fluid to achieve the same (effectively the inverse mechanism). But from a design perspective, I could not figure out a way to avoid leakage of the high pressure over time. My idea was inspired by the action of a syringe. I tried to design a CAD model for the same to simulate it... But could not figure out how to implement all that I read on this topic.

Does a valve or pneumatic system exist that achieves this (am I missing some information that I should know)? And if not, how can I make such a valve? I need to manufacture this as well, so simplicity/availability of resources is important. But any theoretically sound solution will also be greatly appreciated :)

Thanks in advance

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  • $\begingroup$ So what have you calculated so far? What have you looked for and found? Do you think this is a free design service? $\endgroup$ – Solar Mike Jun 18 '18 at 10:07
  • $\begingroup$ I have updated the question with some of the research I did before posting the question. I am not an active member of this community but that does not mean that I disrespect it by taking it for granted. Did not intend to come off as a freeloader, I just didn't know how much to share. Will be mindful of this in the future. $\endgroup$ – Shivam Kaushik Jun 18 '18 at 11:09
  • $\begingroup$ I'm not sure i undersand your requirement. Can you draw a sketch with where you want to have which pressure? $\endgroup$ – mart Jun 18 '18 at 13:04
  • $\begingroup$ Sorry for the unintended large image, I couldn't get it to upload at a smaller size. From the image, what I want to achieve is to create a suction of fluid from the capillaries. Since capillaries will have a tendency to pull the fluid due to surface tension, I want to nullify that and moreover force the fluid to flow to the outlet pipe. The pressure inside the capillaries and the pipe need to be the same. So I need to achieve the forced flow without altering the fluid pressure. $\endgroup$ – Shivam Kaushik Jun 18 '18 at 13:24
  • $\begingroup$ Does the valve close & open, and you want to maintain negative pressure when it's closed? Or do you simply mean xou want negative pressure in the large pipe? $\endgroup$ – mart Jun 18 '18 at 14:24
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Sounds like you're looking for some sort of regulator, not a valve. You did not give any indication to the size or scale of this device, so a link to a specific PN would likely not be useful.

In general, regulators are pressure-reducing devices; most of which operate passively, without electromechanical components. I think that this video, which describes the basic principle of a reg, will help you. Single Stage Regulator: Working Principle

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