Fault protection system for a respiratory conduit heater element
First Claim
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1. A fault protection system for a respiratory conduit heater element comprising:
- detecting means which include means to detect a rapid change of current in said heater element, current interruptor means in series with said heater element, and timer means adapted to control the action of said interrupter means and thereby in use determining the duration of current interruption, said timer means being triggered by said detecting means.
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Abstract
A fault protection circuit for a respiratory conduit heater element in a respirator humidification system is disclosed. The circuit includes a spark detector as well as overcurrent detector. Several variations are included for the spark detector including a two winding transformer, a centre tapped two winding transformer), and a high pass filtered inductor. A semiconductor switching configuration is also disclosed. Once the protection circuit detects a change in current over a certain level, or the average level raises above a threshold, then the current in the heater element is interrupted for a preset period.
31 Citations
18 Claims
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1. A fault protection system for a respiratory conduit heater element comprising:
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detecting means which include means to detect a rapid change of current in said heater element, current interruptor means in series with said heater element, and timer means adapted to control the action of said interrupter means and thereby in use determining the duration of current interruption, said timer means being triggered by said detecting means. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A semiconductor switching circuit for rapidly controlling the AC supply current through a load from a power supply comprising:
two same channel MOSFETs connected in series with their source and gate electrodes respectively tied together, said circuit adapted to receive a switching voltage between the commoned gate and source electrodes, their drain electrodes adapted to be connected to a load and a power supply respectively.
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9. A semiconductor switching circuit for rapidly controlling the AC supply current through a load form a power supply comprising:
two same channel MOSFETs connected in series with their drain and gate electrodes respectively tied together, said circuit adapted to receive a switching voltage between the commoned gate and drain electrodes, their source electrodes adapted to be connected to a load and a power supply respectively.
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10. A fault protection system for a respiratory conduit heater element comprising:
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detecting means which includes a peak current detector for detecting current in the heater element current interruptor means in series with said heater element, and timer means adapted to control the action of said interruptor means and thereby in use determining the duration of current interruption, said timer means being triggered by said detecting means, when a predetermined threshold current is exceeded.
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11. In a respiratory humidification system wherein a conduit connects a patient to a humidifier, said conduit being heated by a respiratory conduit heater element controlled by said humidifier, the improvement comprising that said humidifier includes a fault protection system for said heater element comprising:
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detecting means which include means to detect a rapid change of current in said heater element, current interruptor means in series with said heater element, and timer means adapted to control the action of said interruptor means and thereby in use determining the duration of current interruption, said timer means being triggered by said detecting means. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. In a respiratory humidification system wherein a conduit connects a patient to a humidifier, said conduit being heated by a respiratory conduit heater element controlled by said humidifier, the improvement comprising that said humidifier includes a fault protection system for said heater element comprising:
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detecting means which includes a peak current detector for detecting current in the heater element current interruptor means in series with said heater element, and timer means adapted to control the action of said interruptor means and thereby in use determining the duration of current interruption, said timer means being triggered by said detecting means, when a predetermined threshold current is exceeded.
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Specification