| 摘要 |
A space heater (1) comprises a housing (2) which defines a passageway (10) extending upwardly therethrough from an air inlet (11) to an air outlet (12), and formed by a first lower riser section (28) and a second upper riser section (30). A heat exchanger (20) is located in the second riser section (30). A pair of impellers (25) having backwardly curved vanes (45) located in a lower portion (34) of the second riser section (30) communicate with the first riser section 28 through communicating openings (35), and urge air through the passageway (10) from the air inlet (11) to the air outlet (12). The first and second riser sections (28, 30) are located relative to each other so that air passing from the first riser section (28) into the second riser section (30) through the impellers (25) is initially turned through a first angle of 90 DEG in a clockwise direction to pass horizontally through the impellers (25) and then through a further angle of 90 DEG in an anticlockwise direction into the second riser section (30). This in combination with the provision of the impellers (25) with backwardly curved vanes (45) acts to prevent circulation of air through the passageway (10) resulting from natural convection when the impellers (25) are stationary. <IMAGE> |
