How Indoor Coal Furnaces Work
SECONDARY BURN SYSTEM ( TURBO DRAFT SYSTEM ™)
The exclusive Turbo Draft System ™ was designed into our outdoor furnaces to force fresh air over the open flames. By forcing the gases down to the fire below they are reintroduced into the burning fuel thus giving a hotter combustion and a cleaner burn. This means less heat is lost by escaping into the furnace chimney network.
With our original shaker grate and ash pan design, fresh air is introduced under the fire feeding it oxygen as needed. When the damper is opened oxygen is introduced into the furnace ash pan system to feed the burning coal allowing the fuel to burn hotter and cleaner.
(Forced air and oxygen introduction in furnace is shown in blue on left image.)
ROUND DESIGN & WATER TRANSFER TUBES
The Crown Royal Stoves consists of a round firebox surrounded by a round water reservoir, also known as a water jacket. The combustion of coal heats the water in the surrounding water jacket, which is pumped via insulated underground pipes into your home or buildings.
A round firebox and water jacket design means there are less weld points which reduces the amount of stress on the steel to ensure there is less cracking. The round water jacket design allows more water to be heated efficiently due to the fact that more water is touching the heated firebox surface.
Water transfer tubes are designed into the Crown Royal Stoves, situated directly over the fire
to allow even more water to be heated. As the fire burns, water flows through the transfer tubes giving an even distribution of heat in the water jacket. This design feature eliminates hot and cold spots in the furnaces water supply.
OUTDOOR FURNACE CIRCULATION & HEAT TRANSFER
A four inch (4") gap separates the back of the firebox and the water jacket allowing the supply and return lines, located at opposite corners on the back of the furnace's water jacket, to create a strong enough circulation, forcing the water over and around the firebox to transfer as much heat as possible.
With the use of insulated underground pipes, hot water is moved from the outdoor furnace to your home or buildings, with the use of a circulating pump. The circulating pump is usually hooked to the hot water supply line, located on the bottom connection on the opposite side of the return line. This ensures that the water being used to heat your home or buildings does not have any cold spots.