The current shortages of gas and oil and the high cost of such fuels has stimulated a demand for boilers and furnaces capable of burning comparatively low cost solid fuels such as wood, whereby such boilers and furnaces can be utilized as booster sources of heat in domestic heating systems and, in some cases, may be used as primary heating units.
The present invention seeks to satisfy the above need through the provision of a simplified compact and efficient boiler particularly adapted for use in domestic hot water heating systems and also capable of more general utility. The boiler is rectangular in the interest of space conservation and maximized heating capacity. It possesses an upper horizontal slide-in, slide-out power module to facilitate cleaning and maintenance and this module is a rectangular unit consisting of rows of fire tubes assembled in sealed relationship with a water chamber which surrounds the fire tubes in heat exchange relationship therewith. The water chamber connects directly at the rear of the boiler to cold water return and hot water supply lines. An electrical heating element or elements may also be included on the power module to impart to the boiler a secondary method of heating.
Other important features of the invention are embodied in a unique fire box having simplified and sturdy means to support a cast iron grate and upwardly diverging refractory side walls formed of replaceable fire bricks. An ash removal drawer is arranged below the grate and a horizontal draft tube extending in the back-to-front direction is provided immediately below the grate. A large front access door for the fire box including a draft check makes the feeding of wood into the fire box an easy operation and a separate ash clean-out door with a manual draft device is also provided on the front of the boiler.
Other important features of the invention will become apparent during the course of the following detailed description.
The following U.S. Pat. Nos. are made of record herein under 37 C.F.R. 1.56, but these patents do not possess the above-enumerated features of the present invention coacting in a manner to be described herein for obtaining the operational results of this invention: 1,967,883, 2,553,302, 3,527,260.