basic pressure relief valve design
basic pressure relief valve design
(OP)
I am new to valves, and am trying to design a simple pressure relief system (for air). It should be low cost (valves under 0.25 each.. plastic is fine....)
The inlet would be at 100-150psi and the target system is to be filled anywhere from 20-40psi. This 20-40 psi is to be controlled (+/- 2 psi). The input cannot be controlled and could vary.
So my issue is that I need to be able to limit the differential between the input (chamber) and the output by the amount of psi required. The middle chamber would be open to the outside and would have a spring. The spring deflection would simply be the differential (my target pressure).
this is a linear design (cylindrical shape). Input must come in directly form the back and directly through the other end. There is no side inlet.
1. I know the size of the cylindar containing the chambers to be about 1/2 inch.
2. The sealed chambers are separated by o-ringed disks that can freely move. they need to handle 150 psi.
The issue is I need to prevent the differential (middle chamber) from going above the desired amount (e.g. 40 psi).
The air input to the first chamber would be a one way valve. Another one-way valve would go from the first chamber (down a sealed "tube") to the third. The seals would slide along this central column (inner o-rings).
The third chamber would have a two way valve to the target.
What kinds of valves are used for...
1. one way needle valves (I guess like the kind you use to pump up a basketball.
2. two way valves (to allow back pressure from the target into the third chamber to create the differential).
3. Most important... to allow the spring deflection (at a certain amount) to release the overflow (into the second chamber and out).
Obviously I need to hammer out the design, but it is hard without a beter understanding of 1 & 2 way valves. I do have experience with simple piston valve designs, but it is a side loaded pressurized chamber without pressure relief.
I am trying to understand how a central spring loaded chamber can cause the third chamber to bleed out (it can bleed into the middle chamber which is open to the outside).
Are there ball valves, etc or something that can open when it is contacted? Like if the middle chamber gets small enough from the spring deflection? The size of the deflection determines when relief occurs. The size of this second chamber can be controlled by making the entire second chamber enlargeable via screw threads.
Again this is all brainstorming without better valve understanding.
thanks for any help. blue3715@yahoo.com
The inlet would be at 100-150psi and the target system is to be filled anywhere from 20-40psi. This 20-40 psi is to be controlled (+/- 2 psi). The input cannot be controlled and could vary.
So my issue is that I need to be able to limit the differential between the input (chamber) and the output by the amount of psi required. The middle chamber would be open to the outside and would have a spring. The spring deflection would simply be the differential (my target pressure).
this is a linear design (cylindrical shape). Input must come in directly form the back and directly through the other end. There is no side inlet.
1. I know the size of the cylindar containing the chambers to be about 1/2 inch.
2. The sealed chambers are separated by o-ringed disks that can freely move. they need to handle 150 psi.
The issue is I need to prevent the differential (middle chamber) from going above the desired amount (e.g. 40 psi).
The air input to the first chamber would be a one way valve. Another one-way valve would go from the first chamber (down a sealed "tube") to the third. The seals would slide along this central column (inner o-rings).
The third chamber would have a two way valve to the target.
What kinds of valves are used for...
1. one way needle valves (I guess like the kind you use to pump up a basketball.
2. two way valves (to allow back pressure from the target into the third chamber to create the differential).
3. Most important... to allow the spring deflection (at a certain amount) to release the overflow (into the second chamber and out).
Obviously I need to hammer out the design, but it is hard without a beter understanding of 1 & 2 way valves. I do have experience with simple piston valve designs, but it is a side loaded pressurized chamber without pressure relief.
I am trying to understand how a central spring loaded chamber can cause the third chamber to bleed out (it can bleed into the middle chamber which is open to the outside).
Are there ball valves, etc or something that can open when it is contacted? Like if the middle chamber gets small enough from the spring deflection? The size of the deflection determines when relief occurs. The size of this second chamber can be controlled by making the entire second chamber enlargeable via screw threads.
Again this is all brainstorming without better valve understanding.
thanks for any help. blue3715@yahoo.com
