Publication Date: 2004-Aug-13
The IP.com Prior Art Database
David Cochrane: ATTORNEY [+4]
A stronger and improved coating for solid fuel elements. According to a first aspect of the invention there is provided a coating for a solid fuel element, the coating including a wax and a copolymer resin.
BACKGROUND OF THE INVENTION
This invention relates to solid fuel elements.
United States Patent No. 4,822,380 discloses a carbonaceous fuel, such as coal, charcoal or charcoal briquettes, which incorporates a flammable liquid and which is covered with a coating of a wax material. A drawback with the use of the wax material disclosed in this document is that the wax material does not have great strength. As a result a latex coating is used, in preference to a wax coating, for coal.
It is an object of this invention to provide a stronger and improved coating for solid fuel elements.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a coating for a solid fuel element, the coating including a wax and a copolymer resin.
The coating may comprise 85%-95% by weight wax and 5%-15% by weight copolymer resin, preferably 92% by weight wax and 8% by weight copolymer resin.
The coating preferably has a congealing point of at least 65°C.
A preferred wax coating of the invention has a needle penetration at 25ºC (1/10mm) of more than 10, typically 13 and a kinematic viscosity at 100ºC (cst) of more than 15, typically 18.
The wax is typically a synthetic paraffin wax, such as a Fischer-Tropsch derived wax.
The copolymer resin is typically an ethylene vinyl acetate resin.
According to a second aspect of the invention there is provided a solid fuel element which is coated with the coating described above.
The solid fuel element may be a carbonaceous product and is preferably a briquette made of a compressed combustible material, typically compressed charcoal or coal dust.
The solid fuel element may be impregnated with a liquid fuel or accelerants, such as liquid paraffin.
According to a third aspect of the invention there is provided a method of making a solid fuel element, the method including the steps of:
1. at least partially immersing a fuel element made from combustible material in a liquid fuel or accelerant so that some of the liquid fuel or accelerant is absorbed by the fuel element to produce a liquid fuel-containing fuel element; and
2. coating or sealing the liquid fuel-containing fuel element with a wax coating.
Step 2 preferably includes a first coating stage wherein the liquid-containing fuel element is coated with a primary coating comprising a mixture of liquid fuel or accelerant and coating wax and a second coating stage where the primary coated liquid-containing fuel element is coated with coating wax.
The coating wax preferably includes a wax and a copolymer resin.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawing is a cross-sectional view of a fuel element covered with a coating according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
With reference to the drawing, the numeral 10 indicates generally a coated fuel element of the invention. The fuel element 10 comprises a body 12 which, in this embodiment of the invention, is a briquette made from compressed charcoal and charcoal dust. ...