| 摘要 |
Disclosed is a ventilation-type PTC heater. An arc-shaped upper electrode plate and an arc-shaped lower electrode plate are respectively bonded to an upper end surface and a lower end surface of a PTC ceramic via a silica gel binder, forming a PTC ceramic composition, and an insulating and heat-conducting device is arranged between the PTC ceramic composition and a metal tube, so that the PTC ceramic composition is isolated and fixed within the metal tube. The present invention has small power ageing, MgO sand is used for filling, or an MgO ceramic tube is isolated between the arc-shaped electrode plates and the metal tube, the metal tube and the arc-shaped electrode plates are spatially isolated, and wear and tear of insulating paper by impurities does not occur, permanently preventing loss of insulation strength, and significantly improving insulation reliability. Since the MgO sand or the MgO ceramic tube is tightly wrapped around the PTC ceramic, breakdown caused by air discharge of upper and lower electrodes of the PTC ceramic at high pressure is prevented. The two ends of the metal tube use silica gel plugs and the silica gel is double sealed, to achieve an IP68 waterproof rating. |
