Combustion grate for a pellet stove

An apparatus comprising a primary combustion chamber including a primary grate and an exhaust grate, (i) the primary combustion chamber having a top opening, a bottom opening at least partly obstructed by the primary grate, and a rear opening at least partly obstructed by the exhaust grate, (ii) the primary combustion chamber being structured and arranged so as to enable fuel pellets to fall downward through the top opening into the primary combustion chamber onto the primary grate, intake air to flow upward into the primary combustion chamber through the bottom opening and the primary grate, and exhaust gas to flow rearward out of the primary combustion chamber through the exhaust grate and the rear opening, (iii) the primary grate being structured and arranged so as to support the fuel pellets before partial combustion thereof and to permit partially combusted fuel pellets to fall through the primary grate, (iv) the primary grate defining a primary grate surface with multiple generally vertical primary grate passages through the primary grate, each primary grate passage being smaller in at least one transverse passage dimension than a vertical depth thereof, (v) the exhaust grate defining an exhaust grate surface with multiple rearward exhaust grate passages therethrough, each exhaust grate passage being smaller in at least one transverse passage dimension than a rearward length thereof.