| 摘要 |
PURPOSE:To enhance the heat emission efficiency of a heating device. CONSTITUTION:A heat radiation part is formed in combination of two PTC elements 1 having a positive temperature resistance coefficient and heat radiating blocks 2 having a passage for the air. The total opening area of the passages in the blocks 2 arranged between the two PTC elements 1 is set larger than the total opening area of outer block 2 situated outside of the PTC elements 1. This generates a condition that the rate-of-flow distribution of the air in the passage is generally dense in the central part and coarse as approaching the end. Therefore, the air is admitted to pass through the passage in the block with a rate-of-flow characteristic in compliance with the previous rate-of-flow distribution by setting large the total opening area of the passage in the block 2 arranged between the two PTC elements 1. Accordingly more air passes through the inside block 2 to eliminate risk of stagnation of the heat of PTC element 1, which leads to enhancement of its heat emitting efficiency. |
