MONITORING AND SHUTDOWN APPARATUS

• US 3,735,377 A
• Filed: 03/19/1971
• Issued: 05/22/1973
• Est. Priority Date: 03/19/1971
• Status: Expired due to Term

• Current Assignee: Carl Christopher Kaufman
• Original Assignee: Carl Christopher Kaufman
• Inventors: Kaufman, Carl Christopher
• Primary Examiner(s): Trafton, David L.
• Application Number:
  US05/126,045
• Time in Patent Office: 795 Days
• Field of Search: 340/248P,253P,223 324/161,181 317/33R,33SC,36TD 328/129
• US Class Current: 361/170
• CPC Class Codes: F04C 2270/12 Vibration
• CPC Class Codes: F04C 28/28 Safety arrangements; Monitoring
• CPC Class Codes: H02H 1/04 Arrangements for preventing response to transient abnormal conditions, e.g. to lightning or to short duration over voltage or oscillations; Damping the influence of dc component by short circuits in ac networks
• CPC Class Codes: H02H 5/00 Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection using simulators of the apparatus being protected H02H6/00; specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems H02H7/00

Abstract

A shutdown and/or alarm system is actuated by a monitor. The system includes an AND circuit which comprises a switch and two multivibrators. The multivibrators have different reset times. A signal from the monitor closes the switch for a given time interval, and triggers and initiates resetting of the multivibrators at the end of this interval. Signals from the multivibrators are passed through the switch to energize a shutdown device and/or an alarm.

Claims

1. Control apparatus adapted to be used in monitoring systems in which a monitor establishes a first signal whenever a measured variable exceeds a preselected limit, said apparatus comprising:

first means having three inputs and an output to establish a first output control signal when three input signals representative of preselected conditions are applied to said respective three inputs, said first means including a siliconcontrolled rectifier;

second means responsive to said first signal to apply a signal representative of one of said conditions to the first of said three inputs for a first time interval each time a first signal is established by the monitor, said second means includes a switch connected to the control electrode of said rectifier;

third means responsive to said first signal to apply a signal representative of a second of said conditions to the second of said three inputs for a second time interval following each first time interval; and

fourth means responsive to said first signal to apply a signal representative of the third of said conditions to the third of said three inputs for a third time interval following each first time interval, said third time interval being longer than said second time interval, said third and fourth means establishing potentials which are applied through said switch to said control electrode when said switch is closed.

2. The apparatus of claim 1 whereIn said third and fourth means include first and second one-shot multivibrators, respectively, having different time constants.

3. Control apparatus adapted to be used in monitoring systems in which a monitor establishes a first signal whenever a measured variable exceeds a preselected limit, said apparatus comprising:

a first switch adapted to be closed by said first signal;

a first relay coil to open said first switch when energized;

a second relay coil;

first circuit means to energize said second relay coil when said first switch is closed;

second circuit means responsive to said second relay coil being energized to energize said first relay coil;

third circuit means to establish an output control signal when energized, said third circuit means having a control element therein which energizes said third circuit means when a potential of preselected magnitude is applied to said control element;

first and second one-shot multivibrators having different reset time constants, the reset time of the second being longer than the reset time of the first;

fourth circuit means connected to said first multivibrator to establish a potential of preselected magnitude when said first multivibrator is in a reset condition;

fifth circuit means connected to said second multivibrator to establish a potential of preselected magnitude when said second multivibrator has been triggered but before being reset;

sixth circuit means responsive to said second relay coil being energized to trigger and thereafter initiate the resetting of said first and second multivibrators; and

means responsive to said second relay coil being energized to apply the potentials established by said fourth and fifth circuit means to said control element for a time interval which is of shorter duration than the reset time of the first multivibrator.

4. The apparatus of claim 3 wherein said fourth circuit means comprises a first rectifier connected between a source of reference potential and said first multivibrator so that said first rectifier is non-conductive when said first multivibrator is in a reset state and is conductive when said first multivibrator is triggered, and said fifth circuit means comprises a second rectifier connected between said source of reference potential and said second multivibrator so that said second rectifier is conductive when said second multivibrator is in a reset state and is non-conductive when said second multivibrator is triggered.

5. The apparatus of claim 3 wherein each of said multivibrators has a capacitor and a rectifier connected to the input thereof so that the respective capacitors are discharged when said second relay is energized and are charged when said second relay is deenergized, whereby triggering pulses are applied from said capacitors through the respective rectifiers when the capacitors are charged.

6. The apparatus of claim 3 wherein said third circuit means includes a silicon-controlled rectifier having a control electrode which comprises said control element.