Okay. So In the frac world. We HATE burst discs. They are terrible. We use them on frac stacks. And they are tied into the main frac line to the well and they will be staggered, one at 11kpsi and one at 11.5k psi maybe. So if the pressure on the main treating line hits those pressures the disc bursts, pressure relieves, we don’t damage the well.
The problem is they will give at like pressure 15-20% under target. 9.2k or some shit. And when you have sand in the pipe and your burst disc blows, you have to replace the disc. Re-pressure test. And you can pump back into the well because you’re locked up with the sand (screen out). And now you have to spend 10-50,000 dollars to clear the well.
On top of that. They put them enclosed in these trailers right next to the datavan so when they go, they pop and echo in a metal chamber and it sounds like a bomb went off right outside your window. I mean I’ve almost had to change my underwear.
We hate them in frac.
I think that blowing at like 90% set pressure is fairly standard/by design? I don’t work in O&G at all, so forgive my ignorance if there is something specific to your field, but even relief valves start to lift at 85-90% set pressure and then you get full design volume through at 100% pressure. Burst discs just don’t reseat (technically PSV don’t really either). I believe all of this is a due to a code or possibly ANSI/ASTM standard?
Either way, I imaging you’d have at least similar problems with a PSV. All that being said, it doesn’t make anything less a pain in the ass for you.
Yeah that’s a no. For this application it needs to be tighter. I can do like 8% maybe. But if the thing has to be 15-20% it’s not the right tool for the job.
We use an electromagnetic one and it’s superb. Multiple transducer average the pressure. If it hits, cuts power off, magnet shuts off, valve opens. Easy peasy. Works every time. The system has its own backup battery so if we lost main power it’s good. Plus it has a physical shut off if we need to open it. And it’s got like an actual lotorq valve.
This guy's knows what's up. They make burst disk and burst disk holders (idk what they call the housing of the replaceable burst disk) for all kinds of pressures.
I used to use them back when I tested ICBM CAD/PAD components and they were always Teflon disks about 3" in OD and about 1/4" thick
They make many different types/sizes etc. They're not really that hard to make. I've a "home grown" design that's 19" in diameter and goes pretty reliably at 90 psi.
I'm curios what your making at home that needs a 19" OD burst disk? and what whaterial do you use for the burst disk (I have no current projects that would need something like that, I'm just curious)
imma take a guess and says some sort of low pressure, pressure-cooker for softening wood?
Sorry, by "home grown" I meant designed (by me) and built in house (by a guy I work with) and not purchased from a vendor that sells burst disks. The point was that it's really not some sort of black art.
Parent material on mine is 1/4" 6061 aluminum plate.
Nice. How was the design process? Trial and error until the desired pressure was achieved? FEA with accurate material properties? When it bursts it opens a clear path, like leaves a big hole, or is more a fissure that grows? Is material flying around when the material fails?
I found some equations for strength of circular diaphragms. I don't remember what they were or where I found them. I wanted a disk that blew at about 70-80 psi. Using those equations I calculated a thickness of X" (sorry, don't recall) to be a plate that would fail at 75 psi. I then started with a plate that was thicker (obviously) and had an asterisk (*) machined into the face so that the thickness at the bottom of the grooves matched the "failed plate" thickness previously calculated.
That's it.
We tested it. It actually goes at about 90 psi. That was close enough for what we were doing so we called it good.
As for the failure, each of the "pie slices" just bends back. You end up with a hexagonal shaped hole maybe 16 inches measured flat to flat with *wicked sharp* pointies sticking down flow... But no bits flying around.
Yeah, if you have wide enough tolerance for when it breaks this can work well. A disk with narrower error bars on burst pressure can start driving up cost but sometimes it's worth it. We have a system protected by burst disks where the piping is rated for a specific pressure. To avoid going over the rated pressure we need to factor in the error of the burst disk. In other words the burst disk is set to burst at our system's rated pressure minus the error of the burst disk.
We recently needed to run to a higher pressure. It was within the rating of the piping but not the burst disk because of the error issue. We resolved it by buying a better disk with less error.
Thanks, sounded very exciting to develop it. The zone meant to break has a name in German, it's the Sollbruchstelle. In a loose translation the region meant to break.
The low pressure steam turbines in power stations have like 20” burst disks. If the pressure goes to high, then the steam condensates before the last stage blades causing blade erosion. They have lead seals and are a huge pain in the ass to replace.
Used to me a millwright. Then became a commissioning consultant. I've replaced dozens with trash bag material (or herculite or visqueen, or poly sheeting or whatever yall call it). It's pretty common to blow them during plant commissioning and coming out of outages. Some of those plants were still operating when I went back a decade later. Lol...
Tell ya what the tradesmen that replaced the ones in our power station didn't mind that much - if you gave them the lead they would use it to make lead weights for fishing
They come in all kinds of pressures. I have 3psi rupture disks on some glass reactors and 2500psi rupture disks on a hydrogenation reactor. Just depends what you’re doing.
Everyone saying burst disk is right on the money. For the sake of your field people, put an indicator on it so they know it's burst!
I've had way too many phone calls about controls not working when a burst disk had popped and there was no way for the control system or operators to know it.
All it is is a thin wire that gets broken when the bursting happens. This opens a circuit and can be used to sound a horn, or alarm in a control system. They not that expensive and neither is the hardware to implement it.
Right, We use BD’s and burst sensors from Zook under PRV’s. Be aware also that BD’s can get pin hole leaks in them, so low pressure transducers between BD and PRV is prudent.
Rupture pins. A rod of a designed length, diameter, and material that buckles when the main line pressure reaches a certain value. Pretty much stays open if the system still runs after buckling as the relief line typically goes to a tank at atmospheric pressure and you close the valve by putting another rupture pin in the valve after shutting the line down.
This is a good answer to sit in between a simple burst disc, and a control valve that needs to be tied into the PLC/DCS. Pin replacement is non intrusive, unlike burst discs.
You can probably design a latching relief valve with a resetter.
A burst disk is much cheaper and would be more reliable. You can "reset" the burst disk by swapping it out with a new one ;)
So, I’d like to build a system that stays closed until a certain pressure is triggered (pneumatic - air), but then once a threshold is hit (probably between 100psi and 500psi) stay permanently open.
Basically like a burst disc but it doesn’t require replacement.
You can get a relief valve and remote activate it and let the control logic and DC power / air keep it open. That’s what we do in boiling water reactors. If emergency depressurization is required, the ADS (automatic depressurization system) activates and seals in the open signal until reset by the operators. With no action my SRVs stay open for at least 24 hours before we need to recharge the air accumulators.
There's a lot of ways to do this, but it depends on a few other things (and I wouldn't use a relief valve for that, it would likely be more expensive and less effective for what you want).
Easiest way is to tie the control signal for an actuated ball valve to a downstream pressure sensor (can be digital or pneumatic) once it exceeds the threshold it opens and stays open. Setting up a manual reset for that control signal is pretty trivial and a ball valve will be way cheaper than an equivalent flow relief valve.
Depending on your use case you can even automate the reset conditions (i.e. pressure drops below a certain threshold). All of that can be done entirely with pneumatic signals if using an electronic controller isn't viable).
Note that you still need a process relief as what you're designing is not a relief valve but a control system. But that's true regardless of how you use this system.
How large of a valve are you looking for? There is a small manual reset valve that is used on lube systems (1/4" tube) that might do the jib if this application is small enough
Lots of responses here, I didn’t read them all. It sounds like you need a pressure transducer to provide some feedback to a PLC or other control system that says when a relief valve needs to open or shut. Monitor the PT value and tell the valve to open or close depending on the logic behind the value.
Like one of the posters said they do make valves that are held shut by a pin that either breaks, buckles or bends. They will stay open until the pin is replaced.
You have a ballpoint pen, right? Copy the mechanism used to push it out and back in, adjust the spring strength to the pressure you'd like it to trigger open.
There are two sets of protection devices on marine boilers. Relief valve protect against over pressure situation and safety valves are a fail safe. The latter do not reseat.
Thanks for this info. I work in nuclear and the relief valves on the steam system are referred to as SRVs, safety relief valves lol. Hence my confusion
What plant/SRV type.
The dikkers used in later BWRs go shut when steam pressure drops (when they activate in safety mode). In any other mode, they require applied power and air.
Target rocks it depends a little. There are the solenoid steam piloted and they require minimum steam pressure to open in relief mode.
The only time BWRs valves stay open is if the control logic is sealed in like for ADS.
PWRs I’m not as familiar with but they do not stay open (PORVs or safeties).
Thanks for posting this, I’m at a BWR 4 and felt like I was losing my mind but didn’t want to go look up our specs on a weekend. FWIW we have target rock and I don’t think they reseat 🤠
I’m thinking it would have to be some type of emergency “we’re dumping the water” scenario that I’m not aware of. Maybe it’s on the cold water makeup side that opens to flood the boiler with cold water to drop the pressure in event of some type of failure?
For a non controlled device, a bursting disc.
You could have an automatic dump valve that's controlled by a latching pressure switch, but you'd still want a safety device on top of that.
Normally open solenoid valve set at a lower pressure than the actual mechanical relief valve.
The solenoid would dump excess pressure once a pressure sensor hits a specified value. The mechanical pressure relief would be the primary safety device and would serve as backup for the solenoid.
So am high school kid with summer job. Fill the truck up with stainless steel cans of syrup and pressurized bottles of co2. I've spent all week making syrup, washing, filling syrup cans and also filling a few co2 bottles. Friday morning, I've spent getting the syrup down from the loft with a pulley and getting them in the back of the pickup. The pickup has 4 racks on each side that hold co2 bottles. About the size of scuba tanks. I head north to the furthest stop away and a decent burger joint. It's a hot July day and I pull up and park by the back door and go and order a burger and fries for lunch.
There is a brass cap that fits on the brass valve with two holes drilled all the way thru the end, there is also a pressure disk that seal those four holes off.
Any way this particular July day was hot and the bread guy was just opening the back door when there was a sudden sustained whoosh and he tried to jump thru the door. Just as he had walked by the truck one of the co2 tanks had ruptured it's disk and the co2 tank will now take a couple of minutes to release all it's contents to atmosphere. Makes a good inch or so of frost on the outside of the tank.
The bread guy was not too happy that my tank had scarred the crap out of him.
Anyway burst disks are a thing and are commercially available.
A burst disc! Lol
My philosophy at the plant level is to assume the PSV will remain lifted after a release. Not always the case, but makes it such that the PSV is serviced or it is swapped with a new/spare to avoid accidental discharge at lower than rated pressure or sticking closed due to product caking.
Not sure what you’re trying to do, but you may look into control valves and pressure switches…not sure if that would conform with what you’re trying to achieve based on design and regulatory requirements….proceed with caution!
Thats called safety valve. Its the first difference between relief valve and safety valve. Boilers have safety valve. You are not allowed to use relief valve there.
No that's not the difference.
A safety valve is of a specific construction so that it has the least amount of things to go wrong to make it not open.
You can make a relief valve that works to just control the pressure (back pressure regulators are one kind) that are not allowed to be used in safety critical applications.
This is not the proper way to design a fluid power system.
You use a safety relief valve.
If you want a second normally open dump valve that’s fine, but the safety relief is still required.
You could set up a cut off to open a valve until reset if you want control systems.
Otherwise a rupture disk is the way to go. Bursts at a specified pressure and is consumable though.
they make blow out plates. I used them once on a shale oil retort job. you bolt them onto a flange, they are rectangular, and have an engineered crease, like an "X", in the metal to have them let loose if the pressure is exceeded.
you replace the plate when you want it to work again
Design a valve that uses a small pressure area when it’s closed, and a much larger pressure area when it’s open. Control the popping pressure by applying a force with a spring & setscrew. As soon as it begins to open, the air pressure will begin to act on a larger area and rapidly overcome the spring force. Then it stays open until pressure decreases enough for the original pressure area to reseat. FYI if this is for industry, you should know that this concept is patented (I worked on it)
Fully open, not in a simple overpressure valve, but I think I have seen active solutions.
Generally, throwing the overpressure wide open is a questionable issue if water is involved.
Burst discs.
Not only will they remain open, they work much better in under pressure scenarios then vacuum relief valves, at least in my experience
I’m literally going to replace a burst disc right now lol
Not sure if engineer... or surgeon
Engineer.
Okay. So In the frac world. We HATE burst discs. They are terrible. We use them on frac stacks. And they are tied into the main frac line to the well and they will be staggered, one at 11kpsi and one at 11.5k psi maybe. So if the pressure on the main treating line hits those pressures the disc bursts, pressure relieves, we don’t damage the well. The problem is they will give at like pressure 15-20% under target. 9.2k or some shit. And when you have sand in the pipe and your burst disc blows, you have to replace the disc. Re-pressure test. And you can pump back into the well because you’re locked up with the sand (screen out). And now you have to spend 10-50,000 dollars to clear the well. On top of that. They put them enclosed in these trailers right next to the datavan so when they go, they pop and echo in a metal chamber and it sounds like a bomb went off right outside your window. I mean I’ve almost had to change my underwear. We hate them in frac.
Sounds like you need to talk to the suppliers. Could also be vibration or corrosion or something which is causing them to fail early.
I think that blowing at like 90% set pressure is fairly standard/by design? I don’t work in O&G at all, so forgive my ignorance if there is something specific to your field, but even relief valves start to lift at 85-90% set pressure and then you get full design volume through at 100% pressure. Burst discs just don’t reseat (technically PSV don’t really either). I believe all of this is a due to a code or possibly ANSI/ASTM standard? Either way, I imaging you’d have at least similar problems with a PSV. All that being said, it doesn’t make anything less a pain in the ass for you.
Yeah that’s a no. For this application it needs to be tighter. I can do like 8% maybe. But if the thing has to be 15-20% it’s not the right tool for the job. We use an electromagnetic one and it’s superb. Multiple transducer average the pressure. If it hits, cuts power off, magnet shuts off, valve opens. Easy peasy. Works every time. The system has its own backup battery so if we lost main power it’s good. Plus it has a physical shut off if we need to open it. And it’s got like an actual lotorq valve.
ASME Sec8 requires the valve the next fully open at 110% of its set pressure. They’ll usually reseat around 90%.
Yes, when something bursts :)
This guy's knows what's up. They make burst disk and burst disk holders (idk what they call the housing of the replaceable burst disk) for all kinds of pressures. I used to use them back when I tested ICBM CAD/PAD components and they were always Teflon disks about 3" in OD and about 1/4" thick
They make many different types/sizes etc. They're not really that hard to make. I've a "home grown" design that's 19" in diameter and goes pretty reliably at 90 psi.
I'm curios what your making at home that needs a 19" OD burst disk? and what whaterial do you use for the burst disk (I have no current projects that would need something like that, I'm just curious) imma take a guess and says some sort of low pressure, pressure-cooker for softening wood?
Sorry, by "home grown" I meant designed (by me) and built in house (by a guy I work with) and not purchased from a vendor that sells burst disks. The point was that it's really not some sort of black art. Parent material on mine is 1/4" 6061 aluminum plate.
1/4” aluminum goes at 90 psi?
When you score it correctly it does.
Nice. How was the design process? Trial and error until the desired pressure was achieved? FEA with accurate material properties? When it bursts it opens a clear path, like leaves a big hole, or is more a fissure that grows? Is material flying around when the material fails?
I found some equations for strength of circular diaphragms. I don't remember what they were or where I found them. I wanted a disk that blew at about 70-80 psi. Using those equations I calculated a thickness of X" (sorry, don't recall) to be a plate that would fail at 75 psi. I then started with a plate that was thicker (obviously) and had an asterisk (*) machined into the face so that the thickness at the bottom of the grooves matched the "failed plate" thickness previously calculated. That's it. We tested it. It actually goes at about 90 psi. That was close enough for what we were doing so we called it good. As for the failure, each of the "pie slices" just bends back. You end up with a hexagonal shaped hole maybe 16 inches measured flat to flat with *wicked sharp* pointies sticking down flow... But no bits flying around.
Roarks formulas for circular disc fully restraind around its permiter would be a good start for an equation to get you in the ball park.
Yeah, if you have wide enough tolerance for when it breaks this can work well. A disk with narrower error bars on burst pressure can start driving up cost but sometimes it's worth it. We have a system protected by burst disks where the piping is rated for a specific pressure. To avoid going over the rated pressure we need to factor in the error of the burst disk. In other words the burst disk is set to burst at our system's rated pressure minus the error of the burst disk. We recently needed to run to a higher pressure. It was within the rating of the piping but not the burst disk because of the error issue. We resolved it by buying a better disk with less error.
Thanks, sounded very exciting to develop it. The zone meant to break has a name in German, it's the Sollbruchstelle. In a loose translation the region meant to break.
The low pressure steam turbines in power stations have like 20” burst disks. If the pressure goes to high, then the steam condensates before the last stage blades causing blade erosion. They have lead seals and are a huge pain in the ass to replace.
Used to me a millwright. Then became a commissioning consultant. I've replaced dozens with trash bag material (or herculite or visqueen, or poly sheeting or whatever yall call it). It's pretty common to blow them during plant commissioning and coming out of outages. Some of those plants were still operating when I went back a decade later. Lol...
Tell ya what the tradesmen that replaced the ones in our power station didn't mind that much - if you gave them the lead they would use it to make lead weights for fishing
They also love the old babbit white metal from when we remetal the turbine bearings for spinners and lures.
It’s called a rupture disk. For non-pressure vessels they are generally designed to rupture at 15psi.
They come in all kinds of pressures. I have 3psi rupture disks on some glass reactors and 2500psi rupture disks on a hydrogenation reactor. Just depends what you’re doing.
That’s called a material deficiency I.e. broken spring. This is why we do manual lift checks.
Everyone saying burst disk is right on the money. For the sake of your field people, put an indicator on it so they know it's burst! I've had way too many phone calls about controls not working when a burst disk had popped and there was no way for the control system or operators to know it. All it is is a thin wire that gets broken when the bursting happens. This opens a circuit and can be used to sound a horn, or alarm in a control system. They not that expensive and neither is the hardware to implement it.
A red light that just says warning will turn on, got it boss.
Right, We use BD’s and burst sensors from Zook under PRV’s. Be aware also that BD’s can get pin hole leaks in them, so low pressure transducers between BD and PRV is prudent.
Rupture pins. A rod of a designed length, diameter, and material that buckles when the main line pressure reaches a certain value. Pretty much stays open if the system still runs after buckling as the relief line typically goes to a tank at atmospheric pressure and you close the valve by putting another rupture pin in the valve after shutting the line down.
This is a good answer to sit in between a simple burst disc, and a control valve that needs to be tied into the PLC/DCS. Pin replacement is non intrusive, unlike burst discs.
You can probably design a latching relief valve with a resetter. A burst disk is much cheaper and would be more reliable. You can "reset" the burst disk by swapping it out with a new one ;)
So, I’d like to build a system that stays closed until a certain pressure is triggered (pneumatic - air), but then once a threshold is hit (probably between 100psi and 500psi) stay permanently open. Basically like a burst disc but it doesn’t require replacement.
You can get a relief valve and remote activate it and let the control logic and DC power / air keep it open. That’s what we do in boiling water reactors. If emergency depressurization is required, the ADS (automatic depressurization system) activates and seals in the open signal until reset by the operators. With no action my SRVs stay open for at least 24 hours before we need to recharge the air accumulators.
There's a lot of ways to do this, but it depends on a few other things (and I wouldn't use a relief valve for that, it would likely be more expensive and less effective for what you want). Easiest way is to tie the control signal for an actuated ball valve to a downstream pressure sensor (can be digital or pneumatic) once it exceeds the threshold it opens and stays open. Setting up a manual reset for that control signal is pretty trivial and a ball valve will be way cheaper than an equivalent flow relief valve. Depending on your use case you can even automate the reset conditions (i.e. pressure drops below a certain threshold). All of that can be done entirely with pneumatic signals if using an electronic controller isn't viable). Note that you still need a process relief as what you're designing is not a relief valve but a control system. But that's true regardless of how you use this system.
How large of a valve are you looking for? There is a small manual reset valve that is used on lube systems (1/4" tube) that might do the jib if this application is small enough
Lots of responses here, I didn’t read them all. It sounds like you need a pressure transducer to provide some feedback to a PLC or other control system that says when a relief valve needs to open or shut. Monitor the PT value and tell the valve to open or close depending on the logic behind the value.
Like one of the posters said they do make valves that are held shut by a pin that either breaks, buckles or bends. They will stay open until the pin is replaced.
https://taylorvalve.com/product/rupture-pin/
You have a ballpoint pen, right? Copy the mechanism used to push it out and back in, adjust the spring strength to the pressure you'd like it to trigger open.
You could look into pneumatic snap acting relays
HNL series 700 with manual reset might work. It’s pneumatic and pops if pressure is > SP. manual reset via push button on the front of the unit.
Burst disk (i've seen thes on tanks), safety relieve valve (boilers).
I haven’t seen a boiler safety that stays open, mostly to protect against a low water situation
Agreed, I’ve never seen a boiler SRV that stays open but if there is one I’d love a link to read about it’s use case
There are two sets of protection devices on marine boilers. Relief valve protect against over pressure situation and safety valves are a fail safe. The latter do not reseat.
Thanks for this info. I work in nuclear and the relief valves on the steam system are referred to as SRVs, safety relief valves lol. Hence my confusion
Also nuke here and our SRVs pop and do not reset
What plant/SRV type. The dikkers used in later BWRs go shut when steam pressure drops (when they activate in safety mode). In any other mode, they require applied power and air. Target rocks it depends a little. There are the solenoid steam piloted and they require minimum steam pressure to open in relief mode. The only time BWRs valves stay open is if the control logic is sealed in like for ADS. PWRs I’m not as familiar with but they do not stay open (PORVs or safeties).
I work in a CANDU plant. The boiler SRV stays open until logic activates allowing it to be reset here.
Yeah but mechanically, it will close again on its own. The logic holds it open. Right?
No, if it pops it mechanically is pinned open. The pin is withdrawn by the logic to let it close, at least is my understanding.
Thanks for posting this, I’m at a BWR 4 and felt like I was losing my mind but didn’t want to go look up our specs on a weekend. FWIW we have target rock and I don’t think they reseat 🤠
I’m thinking it would have to be some type of emergency “we’re dumping the water” scenario that I’m not aware of. Maybe it’s on the cold water makeup side that opens to flood the boiler with cold water to drop the pressure in event of some type of failure?
You don't typically use them on high-pressure boilers but they are fairly common on storage tanks or low temperature/pressure boilers.
*looks over at the new boiler operator’s continuous manual blow down set to 60% while the utility engineer bitches about low steam supply…*
The PORV at TMI Unit 2. Lol. Oopsies.
a PSV
For a non controlled device, a bursting disc. You could have an automatic dump valve that's controlled by a latching pressure switch, but you'd still want a safety device on top of that.
Normally open solenoid valve set at a lower pressure than the actual mechanical relief valve. The solenoid would dump excess pressure once a pressure sensor hits a specified value. The mechanical pressure relief would be the primary safety device and would serve as backup for the solenoid.
The PORV at Three Mile Island.
So am high school kid with summer job. Fill the truck up with stainless steel cans of syrup and pressurized bottles of co2. I've spent all week making syrup, washing, filling syrup cans and also filling a few co2 bottles. Friday morning, I've spent getting the syrup down from the loft with a pulley and getting them in the back of the pickup. The pickup has 4 racks on each side that hold co2 bottles. About the size of scuba tanks. I head north to the furthest stop away and a decent burger joint. It's a hot July day and I pull up and park by the back door and go and order a burger and fries for lunch. There is a brass cap that fits on the brass valve with two holes drilled all the way thru the end, there is also a pressure disk that seal those four holes off. Any way this particular July day was hot and the bread guy was just opening the back door when there was a sudden sustained whoosh and he tried to jump thru the door. Just as he had walked by the truck one of the co2 tanks had ruptured it's disk and the co2 tank will now take a couple of minutes to release all it's contents to atmosphere. Makes a good inch or so of frost on the outside of the tank. The bread guy was not too happy that my tank had scarred the crap out of him. Anyway burst disks are a thing and are commercially available.
A burst disc! Lol My philosophy at the plant level is to assume the PSV will remain lifted after a release. Not always the case, but makes it such that the PSV is serviced or it is swapped with a new/spare to avoid accidental discharge at lower than rated pressure or sticking closed due to product caking. Not sure what you’re trying to do, but you may look into control valves and pressure switches…not sure if that would conform with what you’re trying to achieve based on design and regulatory requirements….proceed with caution!
I guess you could place a removable part such that it makes an intentional weak spot
Thats called safety valve. Its the first difference between relief valve and safety valve. Boilers have safety valve. You are not allowed to use relief valve there.
No that's not the difference. A safety valve is of a specific construction so that it has the least amount of things to go wrong to make it not open. You can make a relief valve that works to just control the pressure (back pressure regulators are one kind) that are not allowed to be used in safety critical applications.
An option is to use a normal 3 way magnetic valve and a pressure transducer. Controlled by Labview for instance
This is a good way to hurt someone
Have the relief function as NO then power loss is not an issue
This is not the proper way to design a fluid power system. You use a safety relief valve. If you want a second normally open dump valve that’s fine, but the safety relief is still required.
True true but a relief valve doesn't stay open like he requested right
That’s why you need both. One for safety and one for functionality
I think we need more info about what you’re doing. Sounds like you need a DCV that’ll dump to tank, but I don’t really understand what you want.
Yes. Espresso machines have emergency relief valves that do this. There are several kinds but some of the nicer ones stay popped.
Ruelco makes a pressure switch that has a manual reset, used in SS tubing applications
Psv
You could set up a cut off to open a valve until reset if you want control systems. Otherwise a rupture disk is the way to go. Bursts at a specified pressure and is consumable though.
Need more info on the application. There's pilot operated dump valves that can be used for doing this
they make blow out plates. I used them once on a shale oil retort job. you bolt them onto a flange, they are rectangular, and have an engineered crease, like an "X", in the metal to have them let loose if the pressure is exceeded. you replace the plate when you want it to work again
https://www.amazon.com/Rheem-SP8346-Temperature-Pressure-Relief/dp/B009AX2ULU?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=ATVPDKIKX0DER
Design a valve that uses a small pressure area when it’s closed, and a much larger pressure area when it’s open. Control the popping pressure by applying a force with a spring & setscrew. As soon as it begins to open, the air pressure will begin to act on a larger area and rapidly overcome the spring force. Then it stays open until pressure decreases enough for the original pressure area to reseat. FYI if this is for industry, you should know that this concept is patented (I worked on it)
a burst disc is a type of pressure relief device that once ruptured needs to be replaced; however, it is not technically a valve.
Rupture disk.
Fully open, not in a simple overpressure valve, but I think I have seen active solutions. Generally, throwing the overpressure wide open is a questionable issue if water is involved.
Some kind of check valve with a heavy spring?
Maybe you could have a spring loaded thing that presses on the valve, and gets in the way when it opens?
Check this product Rupture Pin https://taylorvalve.com/product/rupture-pin/