Cone Bottom Inductor Tanks
By Rick Da Tech
Cone Bottom tanks are popular among some biodiesel enthusiasts. This is mostly due to the fact that so many commercially sold biodiesel processors have been made from them. Fuelmeister was the company that popularized this style of processor made using two inductor or cone bottom tanks. Fuelmeister and other companies used them because they were so inexpensive. When purchased in bulk they cost a tenth of the price of metal tanks.
They come in two varieties. The standard inductor tank with a bulkhead adapter bolted in the bottom, and the full draining type with female pipe threads cast into the bottom of the tank. The bulkhead adapter is used to convert a hole in the flat part of the bottom of the tank into pipe threads. This type will retain a cup or two of liquid between the adapter and the tank. The full draining type has a smooth transition from tank to drain pipe that lets all the liquid drain out.
Most cone bottom tanks are made from MDPE or medium density polyethylene. A few are made out of the much stronger and more chemical resisstant HDPE or high density polyethylene. The gold standard for chemical processing tanks is Cross linked High Density Polyethylene (XPLE or PEX). You may have heard of PEX, it is a plastic pipe used for household plumbing. The maximum sustained temperature for MDPE and HDPE is about 65C or 150F. That’s the temperature that the tank will start to soften and change shape. Cross linked polyethylene is much tougher and rated for a slightly higher temperature, usually about 10F higher than HDPE.
Polyethylene will break down when in direct sunlight. The UV is what kills them. Be sure to get only tanks with UV inhibitors added. Even if the tanks have UV inhibitors added, be sure to keep these tanks out of direct sunlight or they will break down over time.
All plastic tanks and drums will melt in a fire. If the drums contain fuel (biodiesel or oil) they will make the fire harder to put out. There are a few pictures of half melted cone bottom tanks on the Internet that show what happens to these tanks when they get hot.
There are some great advantages of cone bottom tanks. In the larger sizes, they are a lot cheaper than steel. You can see inside them. They drain cleanly, if you have the right kind. They have been adapted for use as processor tanks, methoxide mixing tanks, settling tanks, and wash tanks. They are chemically inert and do not promote auto-oxidation. Oil does not form a chicken skin on the inside of the tank like it does with bare steel. And finally they don’t rust.
Cone bottom tanks are available on the internet and locally in most major cities. Shipping can be a major component of the price, so look for a local source before buying them on the Internet.
Inductor Tanks - Cone Bottom Tanks at Amazon.com