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rogelling

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Posts posted by rogelling


  1. With the demand for RV sites for oilfield workers it's gonna be tough to keep out the monthly pay customers that are willing to pay daily rates. You can try to impose a max number of days but it will be easy to pull out and come back for another say 15 days. I would suggest making it Class A only, something that may have crossed your mind already since you are on this forum.


  2. OK, I'll be the first to admit that "best" is a lot opinion rather than fact-based.

    Background:

    Lived in Juneau AK for 2 years.

    Have driven the Alcan 3 times.

    Have cruised (inside passage, etc) 8 times beginning in 1975 for our honeymoon.

    There is NOTHING that will beat the scenery of cruising (by water) to Alaska. Bald eagles, whales, sea lions, sea otters, bears, etc and snow covered mountains until mid summer. Temperature on the water does not vary that much early to late season. The Japanese current pretty well keeps temperatures constant (and cool).

    However, if your plans are to spend an extended period in Alaska, I would sure take the RV. This is particularly true if you are a fisherman and want to do some great fishing.

    ++1


  3. Larry, there is no "best way". It just depends on what you want to do and see. We are driving up in June of 2014 also which will be a new experience for us. My wife is from Alaska and we have traveled up by cruise ferry or our own boat several times but never by road. I would not take the ferry unless I was short on time or wanted extra time in Alaska or was planning to move up there. On the Alaska ferry you do not "cruise", you go from Bellingham to Haines in 3 days! Then you still have to drive to Haines Junction and up to Tok. If you have the time, take the road!


  4. Propane heaters should never be used inside a motorhome due to carbon monoxide emissions. People die from CO poisoning every year due to this practice. The smaller the space and the less it exchanges air with the outside as in a tightly enclosed MH, the greater the danger. At the very least you should have a CO monitor and ventilate the spce which nmakes it harder to heat and negates the need for a heater.LP furnaces are exhaust vented to the outside for a reason.


  5. Not being an engineer or a physicist ( I'm just a country doctor), I was flat wrong about the relative humidity of compressed air. In reviewing my medical physics and some technical websites I have come to realize that the dew point of water vapor is what matters when compressing air. The partial pressure of water vapor is going to increase proportional to the change in pressure of the compressed air, so that the dew point will also increase. Assuming the temp stays fairly constant, the air in your 120 psi tank is going to become saturated at room temp and because the dew point temp will increase to about 70F it is likely that some of the water will condense in the tank, so now the compressed gas is saturated (relative humidity is 100%) but the actual water content is less because of condensation in the tank.

    When it comes to tank air or oxygen, because the pressures are so high, 2500-3000 psi, the dew point would be much higher than room temp and moisture would form inside the tank causing corrosion, so theses gases are dried before being compressed into the tank. I suppose this is the real advantage of nitrogen (tank gas compressed to 3000psi with zero water vapor) vs compressed air to 120psi.

    "4. Why is knowledge of dew point in

    compressed air important?

    The importance of dew point temperature in compressed

    air depends on the intended use of the air. In many

    cases dew point is not critical (portable compressors for

    pneumatic tools, gas station tire filling systems, etc.).

    In some cases, dew point is important only because

    the pipes that carry the air are exposed to freezing

    temperatures, where a high dew point could result in

    freezing and blockage of the pipes. . In many modern factories, compressed air is used to operate a variety

    of equipment, some of which may malfunction if

    condensation forms on internal parts. Certain water

    sensitive processes (e.g. paint spraying) that require

    compressed air may have specific dryness specifications.

    Finally, medical and pharmaceutical processes may treat

    water vapor and other gases as contaminants, requiring a

    very high level of purity.

    http://www.vaisala.com/Vaisala%20Documents/Application%20notes/Dew-point-compressed-air-Application-note-B210991EN-A-LoRes.pdf


  6. Water vapor is a gas, and as such it exerts a pressure. Under STP conditions, the partial pressure of water at sea level is equal to the atm pressure times the relative humidity. If you now take room air at say relative humidity of 60% and compress it under isothermic conditions, water will condense on the bottom of your pressurized container. Thus the amount of water vapor in the compressed gas will be significantly less than what you started with at sea level pressure. This is why you have to periodically drain the water from the bottom of your compressed air tank. The higher the pressure in the tank, the drier the air will be. Going from 1 atm (14.6 psi) to say about 120 psi removes most of the water vapor from the air, roughly from 60% to 6% relative humidity. If you increase pressure to say several 1000 psi as in a cylinder air tank or oxygen tank, the gas in the cylinder is virtually bone dry, close to zero water vapor pressure. That is why when you use oxygen it is bubbled through a water container to increase the water content of inspired gas.

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