Coaxial flue extension systems are constructed from a series of interconnected pipes

Coaxial flue extension systems are constructed from a series of interconnected pipes. The inner pipe 14 is part of the coaxial pipe assembly 10 and is connected to the outer flue pipe 16. The coaxial pipe assembly 10 includes three brackets 18 and the male connector 36. The inner flue pipe 14 is made from 28-gauge galvanized steel. It is fabricated by cutting the material, punching features, and bending the sheet into a hollow tube. It is then sealed using an ACME lock seam 19.

The inner pipe 14 preferably has an embossed seam to form a tight seal. The male connector 36 extends radially inward to define an inner diameter smaller than the outer flue pipe 16. The male connector 41 and female connector 42 have the same dimensions, but the female connectors can be different.

Currently, the male and female coaxial flue pipe assemblies are used for direct vent fireplaces. They form a competitive system. Conventional coaxial pipe assemblies are complex and require double handling during minute adjustment. Additionally, they typically require numerous screws to secure one assembly to the other and must be caulked to prevent leakage. These processes are time-consuming, messy, and inefficient. The present invention is intended to provide a fast, easy, and clean method of connecting multiple coaxial pipe assemblies.

The coaxial flue extension system is used for direct vent gas fireplaces and stoves. The coaxial pipe extends to the outside and vents to the outside through a wall or roof. It is also commonly used in wood-burning fireplaces. Although this system is prior art for fireplaces, it is not yet widely used in gas-burning direct-vent fireplaces.