| 摘要 |
<p>Screened coaxial cables of the type used for underfloor heating systems have an inner conductor surrounded by magnesium oxide, in turn surrounded by a copper sheath covered with plastic isolating material. The inner conductor (1) of a screened cable (5) is connected to the input (13) of an amplifier (8). The input (11) of a second amplifier (7) is connected to the cable screen (3) while the amplifier common terminal (9) is connected to the inner conductor (1). The amplifiers are connected to two signalling and alarm relays (14, 15) which operated visual or audible warning devices (16, 17). The amplifiers are independently adjusted to signal the alarms when predetermined fault conditions exist and can be used as part of a permanent warning system.</p> |
