Or can all fluids (gas and liquid) pass through equally small openings? Lets say we are talking about water as the liquid.
… And I’m sure more complicated answers will follow.
It’s not as simple as the size of the hole. It also depends upon the pressure.
I own three gas wells. Gas will push through porous rock. Water will too if the pressure is great enough. One well produces lots of gas with high pressure and no water. The other two are producing from the same formation and 33+ barrels of water are also pushing through that porous rock. So less gas and pressure are available. At some point the pressure will not be great enough to produce any gas as that pressure will not be enough to push the water. The wells will be “watered in.”
PS. And I have 33 barrels of contaminated water to dispose of daily.
Al Bundy makes an excellent point, one that the manufacturers of Gore-Tex prefer to ignore. The permeation of a membrane depends on both pore size and pressure; I have owned Gore-Tex motorcycle rainsuits that completely failed in the rain – a few times because speed forced water through the fabric, but most often because the pressure of sitting on it (in the puddle of water formed by my crotch and the saddle) forced the water through. Once that pathway is formed, water’s natural cohesiveness sent lots more water through.
Cohesiveness is one of the physical properties resulting from water’s strong polarity and its ability to form hydrogen bonds, and it makes water perform strangely with respect to pores. As long as no water has entered the pores, a membrane like Gore-Tex will resist penetration, in large part because water is more cohesive than adhesive – it tends to stay in drops or droplets, whether you call it surface tension or whatever, and water droplets don’t easily deform or break apart enough to pass through the pores. Once that happens, though, water is equally likely to stick to the water in the pores, or the water around it, and flow results. Other liquids may pass through more easily, though anything that stays liquid at room temperature has enough cohesion to resist flow through a membrane – that’s why it’s a liquid and not a gas.
Goretex, IMHO, is useless for doing real work in real rain – you need real waterproof gear, like the rubberized fabric “foul weather gear” used by fishermen and sailors. I eventually started wearing vinyl rainsuits, which was cheap and worked great, except for the fact that cheap vinyl is thin and tears.
An injection mold is filled with air when the clamp of the press closes it. If the air is not vented from the mold, the air will heat and “diesel” when the plastic is injected in, actually burning the steel over time.
I grind vent channels in the mold to allow the air to escape, but not the liquid plastic.
Liquid nylon is the most fluid of the plastics we process. The vents are .0005-0008" deep.
PP and PS can have vents one thousands deep, and polycarbinate molecules are big enough to not flash a vent .0015" deep.
The way I was taught to think about it is " It doesn’t matter if a door is 15 feet tall if it is not wide enough to fit through".
Injection pressures are usually greater than 10,000 psi
[QUOTE
Goretex, IMHO, is useless for doing real work in real rain – you need real waterproof gear, like the rubberized fabric “foul weather gear” used by fishermen and sailors. I eventually started wearing vinyl rainsuits, which was cheap and worked great, except for the fact that cheap vinyl is thin and tears.[/QUOTE]
Amen to that. Gore-Tex feels great when you put it on or test it under a running faucet. When I try to run in the rain with it, my sweat is enough to start the water wicking through the fabric as if it were porous. I’m better off with water proof nylon. Vinyl or rubber works best for biking as I don’t get as hot.