There is a reason for the backronym for BLEVE “Blast Levels Everything Very Efficiently”
Imagine a pressure cooker 12 inches in diameter. At 15 psig, the force trying to remove the lid is about 1662 pounds. Not only does the lid need to be strong, but the retention mechanism as well. Plus the bottom of the pot, which experiences the same total force, needs to remain relatively flat. bump up the gauge pressure sixfold, and you need some very thick material to ensure that the bottom remains flat and the lid stays on.
Given the safety concerns with respect to a potential BLEVE, a cooking vessel rated for 90 psi would be very heavy and very expensive, and will include a surcharge to provide the manufacturer with a hefty liability insurance policy against the inevitable fatal cooking accident that will occur when a user does something wrong or the cooker suffers a mechanical failure (sell 100,000 units, and someone somewhere somehow will have a problem).
No kidding, I was shocked then saddened to see David Simmons post to this thread.
Why would someone do such a thing?
Another anecdote. My mother used to can using a pressure cooker. One time she did something wrong, I don’t know what, but the safety cap blew and left a dent in the ceiling.
If that could happen with a standard kitchen pressure cooker, what kind of damage could have happened with a malfunctioning/user error high pressure cooker?
He didn’t know how pressure cookers work, or that you’re supposed to depressurise them before opening.
I would think it has to do more with what was capable back when the recipes were invented (cost to make for the general population to purchase) and that the FDA found that cooking at 220 235 250 degrees F. for specific times killed specific bacterias found in foods making them safer for human consumption. Safety laws involving pressurized vessels came into effect after pressure cooking / canning was put into general practice so any laws were probably made to exclude pressure cookers and canners.
Those stamps are for **Unfired **Pressure Vessels. The pressure cooker is a fired vessel.
I have unsuccessfully attempted to find a pressure cooker that can be operated at more than 15 psi, perhaps 30 psi. Obviously it would cook faster, but they don’t seem to be available. 30 psi is not especially high; I have an air compressor that goes up to 125 psi and it does not require any special permits. Pressurized water nuclear reactors operate at around 1,500 psi.
Charles Darwin, the scientist who wrote about evolution, discovered the need for pressure cookers when he was on an expedition at high altitude. Potatoes remained hard even after being boiled for 24 hours. In the early days of pressure cookers, pressures greater than 100 psi were tried. I don’t want anything that high, but it would be nice if I could cook brown rice at 30 psi because that would make it cook faster.
It is unclear why we cannot buy pressure cookers that operate at greater than 15 psi.
Really? Have you read this thread?
While the chef is trying to get thanks, and would be utterly amazed at applause and would die if there was a standing ovation, he is really not interested in *bringing the roof down *.
A higher temperature than we had four years ago, clearly.
The BLEVE link explains “When a liquid boils it turns into a gas. The resulting gas takes up far more space than the liquid did.”
For superheated water flashing to steam at atmospheric pressure, that ratio is about 7000:1
That is, 1 cubic foot of superheated water will flash to 7,000 cubic feet of steam. Not fun to be standing next to that reaction.
My, but you’re an impatient one. My Panasonic rice cooker on quick-mode can ready a batch of brown rice in about 30 minutes. I don’t know how much faster rice could be cooked at 274F (the temp corresponding to 30 psig boiling). Pressure cookers are good for taking hours-long cook times and reducing them to just an hour or two; a pressure cooker that reduces my cook time from 30 minutes to 20 minutes doesn’t add a lot of value.
I wonder what would happen to your cooked rice when you bled off all the pressure at the end of the cook cycle:
Heavy (= difficult to use), expensive to make/transport, expensive to insure the manufacturer against product liability suits, and low demand.
TL,DR: not profitable.
The air compressor is an unfired pressure vessel, while the pressure cooker is fired, it may be that that’s the difference. Vessels with a design temperature less than 210 degrees Fahrenheit are exempt.
ASME code Section VIII specifically exempts vessels having an internal or external pressure not exceeding 15 psi (100 kPa). I don’t know why 15 psi was selected rather than 16 or 20, it’s about one atmosphere of pressure, and that may be it.
OK, fess up! Who hacked Jinx’s account?
That would be one way to steam-clean things.
Might not be in usable condition afterward, but hey–nothing’s perfect.
I laughed.
My mother refused to use a pressure cooker because a friend had been badly hurt by an explosion.
I guess my parents were made for each other because my dad wouldn’t screw in a light bulb without making sure the switch was off. A friend of his had a new light bulb blow up in his face. Had that guy not been wearing glasses, he could have been blinded.
So I won’t use a pressure cooker and I won’t replace light bulbs (I still have fluorescents for outdoor and basement use) without making sure the switch is off.
I think that’s how religions start.
I don’t understand what is meant by “pressure stored,” even though experientially that is as good a way as any to describe it. But it seems kind of just-so-ish.
Before I go off to Wiki “compression,”–which is where I think I should go–after which I’ll probably come back anyway, can someone put “storing pressure” into some more discrete terms?
Also, I’m guessing here, as well the thermodynamic aspects under discussion here, does the term “continuum mechanics” apply to the area of physics I think I’m getting at?
- off to check what c.m. means while he’s there… *