| 摘要 |
<p>The equipment comprises a trapezoidal-section pedestal (1) with a rectangular top surface (3) on which a heater comprising three concentric shells (13-15) is supported by sets of spacers (30-35). The innermost shell (15) surrounds a stack of dissipative plates (48a,48b) and screening plates (42a,42b) spaced apart under the heating element (19) and a grid (16) of radially interconnected circular or helical wires. The innermost shell is open at the level of the preferably spiral element. The taller central and outer shells are open at the higher level (P) of the grid. The dissipative plates have holes for the spacers and/or electrical connections to the element.</p> |
