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Post by the light works on Sept 29, 2014 2:29:10 GMT
Oh, and by the way, the air of a fuel station isn't "dry" at all. It contains lots of water and some oil. Not really healthy to breath. Also you never know where the compressor draws its air from. It could contain gasoline fumes or exhaust fumes from vehicles waiting near the air intake of the compressor with a running engine. Lots of divers have died from carbon monoxide poisoning because their tanks were filled with polluted air, either from a diesel powered compressor itself or a nearby generator or vehicle. yep. I forget how frequently the maintenance division has to recalibrate the CO sniffers on our SCBA stations. |
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Post by silverdragon on Sept 29, 2014 6:46:03 GMT
I have the reason... they finally lost patience when a van turned up and the owner starts pumping up his family collection of pool toys. People miss-used the "Free Air", I have heard rumours that some people even tried filling scuba tanks.... well, THAT ain't gonna work. I forget the pressure SCUBA tanks "inflate" to, but our SCBA tanks go into low air alarm at about 250PSI. I have no idea how they are filled.... but if thats the case, why would anyone want to fill a tank of air.... Unless its some form of Spray gun like a home fence sprayer?.... "It looked like a scuba tank"?.... |
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Post by GTCGreg on Sept 29, 2014 14:01:22 GMT
When I use to do SCUBA diving years ago, the old style steel tanks we used were filled to about 2500 psi. Then they came out with the new aluminum tanks that were filled to 3000 psi. Not something you are going to fill from a normal service station air compressor which usually has a shut-off pressure of 120 to 150 psi.
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Post by the light works on Sept 29, 2014 14:05:19 GMT
We use a standard air compressor to recharge water type fire extinguishers. however, most home users don't have that kind of extinguisher. it might have also been a portable air tank, like some off road drivers carry.
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Post by silverdragon on Oct 1, 2014 7:53:38 GMT
So it wasnt a Scuba tank being filled, I guess whoever "Saw" that was looking at the wrong thing.
I had questioned that myself, but, having only ever scuba dived way back when, I cant remember what the pressure was, it wasnt important then, only that if it got into the red, come up quickly, and I had half-hour max, then its time to come up.
We didnt do any deep diving......
So if a garage air compressor shuts off at 150 psi, its not that much.
Why would anyone want a tank of that kind of pressure?....
Unless its some form of spray.
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Post by c64 on Oct 1, 2014 13:16:56 GMT
So it wasnt a Scuba tank being filled, I guess whoever "Saw" that was looking at the wrong thing. I had questioned that myself, but, having only ever scuba dived way back when, I cant remember what the pressure was, it wasnt important then, only that if it got into the red, come up quickly, and I had half-hour max, then its time to come up. We didnt do any deep diving...... So if a garage air compressor shuts off at 150 psi, its not that much. Why would anyone want a tank of that kind of pressure?.... Unless its some form of spray. It's simple: 14.7 PSI (1 Bar) is the "standard atmospheric pressure". This is the pressure the air around in most areas in the world which are not too high above sea level. Pneumatic pressure is measured as "over pressure", the pressure difference between the inside and the outside of the system because this is what makes pneumatic systems work. Any common pressure rating in PSI or Bar is a relative pressure, relative to the environment. The absolute pressure is irrelevant for pneumatic systems, this is what is measured by barometers and usually in Pascal. When the pressure gauge reads zero, you still have absolute pressure but no relative pressure so the trapped pressure does nothing since it is equal to the environment pressure. In theory, when you increase the pressure, the amount of air (mass) increases while the volume inside a tank stays the same. At 14.7 PSI or 1 Bar (slightly above sea level), you have twice the air mass in a tank. If you open the valve, air of the volume of the tank will come out. A scuba tank isn't large, at 14.7 PSI, you won't get much more than a lung full of air out of it. That's why you need a very immense pressure, to multiply the mass of air the tank carries so you get much more volume out of the tank. A work compressor is used to transfer energy by pressurized air. Paint spray guns and pneumatic motors need volume rather than pressure. The power delivered by a work compressor is pressure multiplied by flow. There is no reason to have much pressure, just a decent flow. Pneumatic tools usually run on 6 Bar, spray guns need less than 4 Bar. For air storage, pressure is most important. So a work compressor and a scuba dive compressor are very different. Kind of like the voltage on a common outlet and high tension lines. |
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Post by the light works on Oct 1, 2014 13:39:25 GMT
So it wasnt a Scuba tank being filled, I guess whoever "Saw" that was looking at the wrong thing. I had questioned that myself, but, having only ever scuba dived way back when, I cant remember what the pressure was, it wasnt important then, only that if it got into the red, come up quickly, and I had half-hour max, then its time to come up. We didnt do any deep diving...... So if a garage air compressor shuts off at 150 psi, its not that much. Why would anyone want a tank of that kind of pressure?.... Unless its some form of spray. most likely just a portable compressed air tank - like I said, some off road drivers carry one instead of a portable compressor. |
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Post by GTCGreg on Oct 1, 2014 13:59:25 GMT
For most applications, those portable air tanks are pretty useless. You may be able to fill a small tire or top off a larger one. Where they come in handy is if you need to operate something like a pneumatic nailer of stapler for a short time and have no power to run a compressor.
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Post by the light works on Oct 1, 2014 14:34:07 GMT
For most applications, those portable air tanks are pretty useless. You may be able to fill a small tire or top off a larger one. Where they come in handy is if you need to operate something like a pneumatic nailer of stapler for a short time and have no power to run a compressor. and when I think about it, I think I've heard of people converting old SCUBA tanks to portable compressed air tanks. - the volume is pretty low, but when you don't need all that much, you can get away with it. |
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Post by c64 on Oct 1, 2014 15:20:45 GMT
For most applications, those portable air tanks are pretty useless. You may be able to fill a small tire or top off a larger one. Where they come in handy is if you need to operate something like a pneumatic nailer of stapler for a short time and have no power to run a compressor. …or you don't like to carry one. ;-) When climbing on a roof, a long hose down has a pretty intense pull. Also you can trip over the hose. Nowadays you can buy very light box shaped plastic tanks. A major brand offers two "briefcases" which look almost identical. One is the compressor and the other one the backpack. Refilling from the compressor takes only a few seconds. |
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Post by the light works on Oct 1, 2014 15:24:55 GMT
and how often do you have to climb back down the ladder to refill the "backpack?" here, they just use a small compressor and secure it on the roof, or tie off their hose to the top of their ladder.
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Post by GTCGreg on Oct 1, 2014 16:11:11 GMT
and how often do you have to climb back down the ladder to refill the "backpack?" here, they just use a small compressor and secure it on the roof, or tie off their hose to the top of their ladder. When they replaced the roof on our house a few years ago, the roofing company had a gasoline engine driven compressor on the ground and a connection manifold mounted on the top of the "elevator" ladder that they used to lift the shingle bundles up with. They then had three nail guns tied to the manifold and one air line from the manifold to the compressor. |
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Post by the light works on Oct 1, 2014 16:15:44 GMT
and how often do you have to climb back down the ladder to refill the "backpack?" here, they just use a small compressor and secure it on the roof, or tie off their hose to the top of their ladder. When they replaced the roof on our house a few years ago, the roofing company had a gasoline engine driven compressor on the ground and a connection manifold mounted on the top of the "elevator" ladder that they used to lift the shingle bundles up with. They then had three nail guns tied to the manifold and one air line from the manifold to the compressor. they're a pretty big company if they have their own shingle lift - here, the culture is that the lumberyard delivers the material onto the roof with THEIR truck before the install starts (usually while they are stripping the old roofing) |
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Post by GTCGreg on Oct 1, 2014 18:19:15 GMT
When they replaced the roof on our house a few years ago, the roofing company had a gasoline engine driven compressor on the ground and a connection manifold mounted on the top of the "elevator" ladder that they used to lift the shingle bundles up with. They then had three nail guns tied to the manifold and one air line from the manifold to the compressor. they're a pretty big company if they have their own shingle lift - here, the culture is that the lumberyard delivers the material onto the roof with THEIR truck before the install starts (usually while they are stripping the old roofing) Probably varies depending on the roofing company. The lift these people had was a pretty simple device that just attached to a regular extension ladder. As simple as it was, it worked surprisingly well. |
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Post by the light works on Oct 2, 2014 0:08:14 GMT
they're a pretty big company if they have their own shingle lift - here, the culture is that the lumberyard delivers the material onto the roof with THEIR truck before the install starts (usually while they are stripping the old roofing) Probably varies depending on the roofing company. The lift these people had was a pretty simple device that just attached to a regular extension ladder. As simple as it was, it worked surprisingly well. ah, here, the truck has a 30 foot conveyor boom that they load the material onto the roof with. I was thinking the roofing companies had one of those. |
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Post by wvengineer on Oct 2, 2014 3:02:56 GMT
I have used those vacuums at car washes before, but they always seem to have incredibly poor suction. I prefer to use a Shopvac to clean out my car. Works WAY better.
Around here, for some reason, no one will put shingles on the roof. They will delivery them on a pallet and drop it on the ground of the construction site. Either you have to rent a fork lift from someone else, Or you get to carry them all up yourself. I wonder if there is some weird WV law preventing roof top delivery. I have done shingles in several parts of the state and none will put them up there.
One neat gizmo I saw at the hard ware store a while back was a portable air pack that used a version of a paint ball gun air tank that attached to a regulator worn on a belt clip. This fed an air hose to the tool. No idea how well it worked though.
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Post by GTCGreg on Oct 2, 2014 4:17:08 GMT
I have used those vacuums at car washes before, but they always seem to have incredibly poor suction. I prefer to use a Shopvac to clean out my car. Works WAY better. Around here, for some reason, no one will put shingles on the roof. They will delivery them on a pallet and drop it on the ground of the construction site. Either you have to rent a fork lift from someone else, Or you get to carry them all up yourself. I wonder if there is some weird WV law preventing roof top delivery. I have done shingles in several parts of the state and none will put them up there. One neat gizmo I saw at the hard ware store a while back was a portable air pack that used a version of a paint ball gun air tank that attached to a regulator worn on a belt clip. This fed an air hose to the tool. No idea how well it worked though. That was probably CO 2 powered and not air. You can store a lot more energy in a smaller tank using CO 2 because it liquifies at a relatively low pressure of around 850 PSI. That's why you need a regulator to reduce the 850 to a working pressure of around 90 psi for most air tools. The tank will hold a constant pressure until all the liquid is converted to gas. The disadvantage is that the tank will get very cold if you draw the gas off too fast due to the evaporation of the liquid CO 2 in the tank. |
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Post by c64 on Oct 2, 2014 12:10:41 GMT
and how often do you have to climb back down the ladder to refill the "backpack?" here, they just use a small compressor and secure it on the roof, or tie off their hose to the top of their ladder. Well, it worked pretty long. I think I understand your confusion, over here, shingles are not nailed in place, we use roof tiles which keep them self in place by gravity. The air tool is only used for the "steam barrier" and the insulation. The tacker doesn't need all that much air. The nails for the beams are usually hammered in place, air tools are not good at this size of nails. I think they worked a quarter hour or so until the guy carrying more material bought a fresh backpack along. Here's a Video. In this case, the "steam barrier" is glued together and they use a nail gun for the top layer of rafters. They do it a bit different from what I am used to, they made two layers of rafters, I am only familiar with nailing a single layer of horizontal rafters by hand using thick nails. |
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Post by the light works on Oct 2, 2014 13:48:53 GMT
I have used those vacuums at car washes before, but they always seem to have incredibly poor suction. I prefer to use a Shopvac to clean out my car. Works WAY better. Around here, for some reason, no one will put shingles on the roof. They will delivery them on a pallet and drop it on the ground of the construction site. Either you have to rent a fork lift from someone else, Or you get to carry them all up yourself. I wonder if there is some weird WV law preventing roof top delivery. I have done shingles in several parts of the state and none will put them up there. One neat gizmo I saw at the hard ware store a while back was a portable air pack that used a version of a paint ball gun air tank that attached to a regulator worn on a belt clip. This fed an air hose to the tool. No idea how well it worked though. That was probably CO 2 powered and not air. You can store a lot more energy in a smaller tank using CO 2 because it liquifies at a relatively low pressure of around 850 PSI. That's why you need a regulator to reduce the 850 to a working pressure of around 90 psi for most air tools. The tank will hold a constant pressure until all the liquid is converted to gas. The disadvantage is that the tank will get very cold if you draw the gas off too fast due to the evaporation of the liquid CO 2 in the tank. our vacuums are dual motor vacuums, and as long as both motors are running, and nobody has clogged the hose, they will collect anything that gets in the way. - they run on 25A circuits. as for rooftop delivery, it is probably a cultural thing - but insurance companies may be involved. and as for the tanke - our SCBA tanks will do that, too - it's a phenomenon that leads to people getting the nicknme "Ice Cube" - because I've actually seen people freeze ice onto the valve before. |
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Post by the light works on Oct 2, 2014 13:53:04 GMT
and how often do you have to climb back down the ladder to refill the "backpack?" here, they just use a small compressor and secure it on the roof, or tie off their hose to the top of their ladder. Well, it worked pretty long. I think I understand your confusion, over here, shingles are not nailed in place, we use roof tiles which keep them self in place by gravity. The air tool is only used for the "steam barrier" and the insulation. The tacker doesn't need all that much air. The nails for the beams are usually hammered in place, air tools are not good at this size of nails. I think they worked a quarter hour or so until the guy carrying more material bought a fresh backpack along. Here's a Video. In this case, the "steam barrier" is glued together and they use a nail gun for the top layer of rafters. They do it a bit different from what I am used to, they made two layers of rafters, I am only familiar with nailing a single layer of horizontal rafters by hand using thick nails. here, they power nail the roof sheathing on, then hand staple any moisture barriers on with "hammer tackers" and then apply whatever roofing - usually asphalt shingles, which are air nailed, cedar shakes might get applied either way, any form of tile would get hand nailed - though any backing would get power nailed, and sheet metal roofing gets screwed in place. |
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