November 6, 2018 at 8:00 am #886573heavydpjParticipant
I’ve recently discovered that placing ice on the metal top of the IP to bring the pressure down without using the vent (rapid NPR). It’s similar to putting a pressure cooker in the sink.
Has anyone else thought about / tried this?November 6, 2018 at 11:47 pm #886577GregParticipant
It strikes me as a dangerous practice for several reasons.
1. You are placing water on an electrical appliance where it is not intended to be. Yes I know it is in the form of ice, but ice has this nasty habit of melting when placed in contact with hot objects.
2. You are placing extra heat stress on the IP. This could lead to microscopic cracks developing – metal/plastic fatigue. This in turn could lead to catastrophic failure (read bomb!) at an indeterminate time in the future.November 7, 2018 at 7:53 am #886581heavydpjParticipant
I see your points.
However, the channel around the lid is already designed to collect water from the lid (which happens fairly frequently), and channel it to the collection point at the rear of the unit.
As for the pressure / thermal stress issue. I would note that the max pressure for the IP is about 40kPa, which is about a fifth the pressure of a can of soda at room temperature (240 kPa), encased in a .097mm thick aluminum can. The IP, on the other hand is encased in 1.25mm thick stainless steel, so there isn’t a lot of worry about a “bomb” going off in the kitchen.
Additionally, I would note that the max working temp of the IP is 244f, with the lid (according to my measurements) reaching a max of about 205f. The introduction of a several 32f ice cubes is not enough to introduce the thermal stress to the point that thermal crazing will occur. I would also note that cooling manual pressure cookers under cold running water or ice baths is a common practice (which is where I got the idea from).
The plastic molding is simply decorative, and does not provide any pressure holding function, so that aspect is also something that I’m not overly concerned about.November 7, 2018 at 4:07 pm #886584GregParticipant
“I would also note that cooling manual pressure cookers under cold running water or ice baths is a common practice (which is where I got the idea from).”
And is now advised against because of potential problems.
Soda cans are not normally subject to repeated bouts of > boiling on one side and freezing on the other.
I don’t own an IP and was unaware that they have a channel to collect moisture running down the outside of the lid. I know they are based on rice cookers which have a channel designed to collect moisture running down the inside. At least that’s how mine works. I assumed they work they same way.
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