Thanks Neil,
This confirms my thoughts on the subject. I like your analogy of the
heating pad and match. It gets the point across!!
Tom, Redding CA - #216 D/GCC
Albaugh, Neil wrote:
> Tom;
>
> At Bonneville, you could probably even use a small thermosiphon solar panel
> to heat the oil or water!
>
> There are two types of heaters that are used on dry sump oil tanks, a pad
> type and a cartridge type. The cartridge type is small and convenient; it
> even screws into a fitting in the wall of the tank and it's immersed in the
> oil. Unfortunately, its small size is a big limitation on its ability to
> heat the oil. If a high-wattage cartridge heater is used to heat the oil, it
> overheats the oil that is in direct contact with it. Oil doesn't have very
> good thermal conductivity, so the oil in contact with the heater gets too
> hot and burns while oil further away doesn't absorb much heat. Eventually,
> there will be a convection flow established and the whole tank will be
> heated but the cartridge heater is still too hot.
>
> The basic problem is the heating element's high "watt-density". A cartridge
> heater has such a small surface area, it can't transfer its heat to the oil
> efficiently, so it gets very hot for a given amount of electrical power. A
> pad type heater is usually a silicone rubber pad with an electrical heating
> wire providing heat that is distributed over its entire surface.
> This type of heater is usually bonded to the outside of the aluminum oil
> tank. The tank wall helps to spread the heat over an even wider surface
> area. For the same wattage, the pad heater warms the oil to the same
> eventual temperature as a cartridge heater but the oil in contact with the
> tank wall next to the heating pad is not overheated.
>
> It's a matter of heat density. Similar to the choice of sitting on a heating
> pad or having a match lit under your backside.
>
> Regards, Neil Tucson, AZ
/// unsubscribe/change address requests to majordomo@autox.team.net or try
/// http://www.team.net/mailman/listinfo
/// Archives at http://www.team.net/archive/land-speed
/// what is needed. It isn't that difficult, folks.
|