利索-全球专利检索

  1. 登录
  2. 注册

搜索结果

75 条记录 (耗时 0.013 秒)

    Temperature control circuits
    30.
    发明授权
    Temperature control circuits 失效
    温度控制电路

    公开(公告)号：US3745308A

    公开(公告)日：1973-07-10

    申请号：US3745308D

    申请日：1971-07-01

    申请人： HEINEMANN ELECTRIC CO

    发明人： LEFFERTS P

    IPC分类号： G05D23/24 ,  H05B1/02

    CPC分类号： G05D23/2401

    摘要： A system for applying electrical power to a heater element in response to a manual command, periodically monitoring changes in the temperature of the heater element by sensing its resistance during the heating process, and automatically disconnecting power from the heater when it reaches a preselected temperature. The system includes control circuits comprising an electrical bridge, including the heater element itself as one arm thereof, a comparator circuit for periodically sensing the output of the bridge at a time when the bridge is fully energized. The comparator generates a comparator signal each positive half cycle of the power source dependent upon the temperature of the heater element. A relay controls power to the bridge in response to a control signal generated by a bistable circuit. The bistable circuit is initially switched ''''on'''' in response to a manual command which results in power being applied to the bridge. Subsequently, the bistable circuit is switched ''''off'''' by each positive half cycle of power applied to the bridge circuit and ''''on'''' by the comparator signal at the end of each positive half cycle of power to the bridge circuit, so long as the temperature of the heater is below the preselected value. Each time the bistable circuit is switched ''''on,'''' a half wave of power is applied to the relay to maintain it in an energized condition. When the temperature of the heater reaches the predetermined value, the comparator signal ceases to switch the bistable circuit ''''on'''' and power is disconnected from the bridge and the heater.