| 摘要 |
<p>The heating element, for fan-assisted air heaters, presents a low resistance to air flow giving high efficiency. The helical resistance wires do not glow red. The resistance wire helix zig-zags between plane parallel insulating plates (6). The plane of the zigzag is at right angles to the plane of the plates and to the direction of air flow. The air flows along the surfaces of the plates. The vertical plates are held top and bottom by horizontal plates. There are at least two pairs of vertical plates each supporting a zigzagging helix.</p> |
