Valve to vent entire volume upon reaching a set pressure

  • #1
nlis12
32
3
Greetings,

I have an experiment that pressurizes a small volume at variable rates. 1, 2, and 3 psi/sec. I am trying to think of a way to reproducibly drop the pressure of the container by a known amount while it is being pressurized. Are there valves for this type of experiment? What are other ways I can achieve a controlled pressure drop?

Any help or insights are welcome.
Thank you.
 

Answers and Replies

  • #2
ChemAir
Gold Member
172
178
Can you clarify the expression "drop the pressure of the container by a known amount while it is being pressurized?" Some numbers here to get a handle on the pressures being discussed would be helpful.
 
  • #3
nlis12
32
3
Let's say the container is being pressurized at 2psi a second. I want to decrease the pressure of the system by 2psi at any point in time in a reproducible way.

Does this make sense?
 
  • #4
JBA
Science Advisor
Gold Member
1,542
461
The problem is that the pressurization rate will change as the receiving vessel's pressure rises so there is no one vent valve flow rate and time to shutoff combination that will work. The only possible solution I can envision right now might be a possibly vent valve controlled by a computer module with a receiving vessel mounted pressure sensor that is programmed with a time vs. sensing pressure opening time curve contoured to the system supply rate vs the vent valve flow rates that when triggered will open the vent valve for a time proportional to the supply vs vent valve flow rates at any given vessel pressure.
 
  • #5
anorlunda
Staff Emeritus
Insights Author
11,017
8,367
You don't say how accurate and how repeatable it has to be. For maximum precision, I agree with @JBA , a feedback loop and a computer is the most direct approach. But if you don't need precision, then a solenoid valve that opens for a fixed duration of time may be good enough.
 

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