Keeping Propane Tanks Warm
One of the biggest drawbacks to using most propane tanks is that they were never designed for the type of heavy flow that fire artists put them through.
Tanks were designed for safety in mind. When the Department of Transportation came up with the requirement that all propane tanks must have an OPD (Overflow Protection Device)
What happens is that as you use a propane tank in a high volume application, you get a nifty demonstration of the venturi effect. As the gas passes through a narrow orifice, it tends to cool. The consequence is that the tank starts to cool dramatically and begins to frost up. Depending on how quickly you drain the tank, it can start to ice up as well. The problem is that as the tank cools down, the propane becomes less efficient at off-gassing, which means you get less pressure out of the tank.
So if you plan on using a high volume of propane for your artwork, you are going to want to think of a way to warm the tank up.
The easiest way to do this is to place the propane tank in a bucket of water big enough to fit the tank in the water. A plastic container that is around 16" wide and no taller than 16" is preferable. A 30 gallon trash can will work great, but it requires a lot of effort to lift a 100# propane tank into a high-walled container like a trash can. a 6-10 gallon beverage cooler/ice bucket is pretty good.
Water will slow down the icing of the tank, but depending on your volume, water alone will not be enough. After a while, the tank will still develop ice around the exterior. If you have enough volume, you can end up with a tank that will freeze nearly all frozen in the bucket of water.
You may have to find ways to warm the water.
Warming the Water
A propane tank in a bath of warm water is the best way to keep up your tank working in an efficient manner. You do not want the water too hot or you could run into problems with the tank venting. The problem is, how do you heat water? Here are a few suggestions of popular ways to heat the water.
Coffee Cup Warmer
This little device has a solid wire loop that connects to a two-wire electric cord. Drop it in a cup of water and in about 1-3 minutes, the water is hot enough for coffee. Attaching one to the side of a bucket should keep the water very warm.
However, this device has some drawbacks. One, it has no temperature control so you have to monitor it because it can get the water hot enough to boil. If it makes contact with the side of a plastic bucket, it will melt a hole in the side. It also consumes 1-2,000 watts of electricity, which means you need the output of a small generator just to run it.
The cost is under $20.00, so it's cheap, but the low price might not outweigh the drawbacks.
Electric Tea Kettle
I have found that an electric tea kettle is a really great way of heating up water quickly and easily. It will heat a quart of water to a boil in 1-3 minutes. Most have a built-in temperature sensor so that they turn off once they boil and you can set them for a lower temperature.
The drawback is that they do use around 1000 watts of electricity. However, the fact that they do turn themselves off and have some safety features makes them a great way to heat water.
Coleman Portable Hot Water Heater
This heater will heat cold water to over 100�F in 5 seconds with 30,000 BTUs, and features hot water temperatures up to 160�F. This is the perfect device if you are running a trough of propane tanks you need to keep warm.
The unit is very well contained, reliable and can be adapted easily to run off larger propane tanks which is cheaper in the long run than using 16 oz bottles. It has a built-in faucet and can be used for heating water for warming propane tanks, use for a shower or in a camp kitchen. It comes with an AC and a car adapter or will run with a 6 volt rechargeable battery. It will heat up to 40 gallons of water using one 6 volt battery and a 16 oz propane bottle.
The drawback is that at $190.00, the price is a bit steep, but only slightly more expensive than the Zodi and more useful.
Zodi Hot Tap Traveler Shower
As a hot water shower, this device is wonderful. It will produce hot water in no time and give you a nice hot shower. I tried to adapt it to working as a propane water heater for warming tanks and it will do the job fairly well. This unit comes with a carrying case to pack up the accessories. You can adapt it with a propane tree to run off of a larger propane tank which helps because the single 16 oz bottle unit is a bit top heavy.
This unit has a few drawbacks. With a It requires 4 D cell batteries and they could easily drain in an hour. The unit is top heavy and works far better mounted on a 20# propane tank with a propane tree. It also has some issues with blowing out in even slightly windy conditions and the hoses come off easily, which is a problem since you really do not want hoses coming off at a bad time.
An electric blanket is an easy way to keep tanks warm. They are UL rated, washable and produce an even amount of heat. Wrapping blankets allows you to skip the water bath altogether, so there is less hassle. You can strap a propane tank to a dolly and wrap a blanket around both objects. Another plus is that they fold up and store easily and can be used for multile tasks, for instance warming up crew.
Every blanket I found was made out of acrylic. I would recommend a cotton sheet or a towel to wrap around the tank so that if any ice forms, it does not make contact with the blanket. Otherwise the ice will really latch onto the fabric and be hard to remove from the tank when you are breaking things down later.
To Be Continued